WorldWideScience

Sample records for producing radiative shocks

  1. Nonthermal Particles and Radiation Produced by Cluster Merger Shocks

    Science.gov (United States)

    2003-09-10

    NONTHERMAL PARTICLES AND RADIATION PRODUCED BY CLUSTER MERGER SHOCKS Robert C. Berrington and Charles D. Dermer Naval Research Laboratory, Code 7653...of the merging cluster and is assumed to be constant as the shock propagates outward from the cluster center. In this paper , we model the cluster ...emission in the60–250 eV band for a number of clus- ters. These clusters include Virgo , Coma, Fornax, A2199, A1795, and A4059 (Lieu et al. 1996a, 1996b

  2. Double shock front formation in cylindrical radiative blast waves produced by laser irradiation of krypton gas

    Energy Technology Data Exchange (ETDEWEB)

    Kim, I.; Quevedo, H. J.; Feldman, S.; Bang, W.; Serratto, K.; McCormick, M.; Aymond, F.; Dyer, G.; Bernstein, A. C.; Ditmire, T. [Center for High Energy Density Science, Department of Physics, The University of Texas at Austin, C1510, Austin, Texas 78712 (United States)

    2013-12-15

    Radiative blast waves were created by irradiating a krypton cluster source from a supersonic jet with a high intensity femtosecond laser pulse. It was found that the radiation from the shock surface is absorbed in the optically thick upstream medium creating a radiative heat wave that travels supersonically ahead of the main shock. As the blast wave propagates into the heated medium, it slows and loses energy, and the radiative heat wave also slows down. When the radiative heat wave slows down to the transonic regime, a secondary shock in the ionization precursor is produced. This paper presents experimental data characterizing both the initial and secondary shocks and numerical simulations to analyze the double-shock dynamics.

  3. Instantaneous x-ray radiation energy from laser produced polystyrene plasmas for shock ignition conditions

    International Nuclear Information System (INIS)

    Shang, Wanli; Wei, Huiyue; Li, Zhichao; Yi, Rongqing; Zhu, Tuo; Song, Tianmin; Huang, Chengwu; Yang, Jiamin

    2013-01-01

    Laser target energy coupling mechanism is crucial in the shock ignition (SI) scheme, and x-ray radiation energy is a non-negligible portion of the laser produced plasma energy. To evaluate the x-ray radiation energy amount at conditions relevant to SI scheme, instantaneous x-ray radiation energy is investigated experimentally with continuum phase plates smoothed lasers irradiating layer polystyrene targets. Comparative laser pulses without and with shock spike are employed. With the measured x-ray angular distribution, full space x-ray radiation energy and conversion efficiency are observed. Instantaneous scaling law of x-ray conversion efficiency is obtained as a function of laser intensity and time. It should be pointed out that the scaling law is available for any laser pulse shape and intensity, with which irradiates polystyrene planar target with intensity from 2 × 10 14 to 1.8 × 10 15 W/cm 2 . Numerical analysis of the laser energy transformation is performed, and the simulation results agree with the experimental data

  4. Radiative relativistic shock adiabate

    International Nuclear Information System (INIS)

    Tsintsadze, L.N.; Nishikawa, K.

    1997-01-01

    The influences of thermal radiation on the state equation of shock waves, derived in the previous paper [L. N. Tsintsadze, Phys. Plasmas 2, 4462 (1995)], are studied and a series of relations of thermodynamic quantities that hold for shock waves are derived. It is shown that the presence of radiation can strongly change the compressibility of the plasma. It is well known that for polytropic gases the compressibility cannot change more than four times the initial value in the case of nonrelativistic temperatures. The numerical calculations show that there are no such restrictions, when the radiation energy exceeds the kinetic energy of the plasma. The ultrarelativistic temperature range is also covered in our numerical calculations. Also studied are the influences of the radiation on the PT and the TV diagrams. A significant modification due to radiation is found in every case studied. copyright 1997 American Institute of Physics

  5. Shock Producers and Shock Absorbers in the Crisis

    OpenAIRE

    Sinn, Hans-Werner

    2009-01-01

    It is not surprising that the U.S. has been by far the world’s largest shock producer in this crisis. The big shock absorbers on the other hand were Japan, Russia and Germany, whose exports shrank more than their imports.

  6. Electromagnetically driven radiative shocks and their measurements

    International Nuclear Information System (INIS)

    Kondo, K.; Watanabe, M.; Nakajima, M.; Kawamura, T.; Horioka, K.

    2005-01-01

    Experimental results on a generation of strong shocks in a compact pulse power device are reported. The characteristics of strong shocks are different from hydrodynamical shocks' because they depend on not only collisions but radiation processes. Radiative shocks are relevant to high energy density phenomena such as the explosions of supernovae. When initial pressure is lower than about 50 mtorr, an interesting structure is confirmed at the shock front, which might indicate a phenomenon proceeded by the radiative process. (author)

  7. Theory and Experiment on Radiative Shocks

    Science.gov (United States)

    Drake, R. Paul

    2005-07-01

    The current generation of high-energy-density research facilities has enabled the beginnings of experimental studies of radiation hydrodynamic systems, common in astrophysics but difficult to produce in the laboratory. Radiative shock experiments specifically have been a topic of increasing effort in recent years. Our group and collaborators [1] have emphasized the radiographic observation of structure in radiative shocks. These shocks have been produced on the Omega laser by driving a Be piston through Xenon at velocities above 100 km/s. The talk will summarize these experiments and their results. Interpreting these and other experiments is hampered by the limited range of assumptions used in published theories, and by the limitations in readily available simulation tools. This has motivated an examination of radiative shock theory [2]. The talk will summarize the key issues and present results for specific cases. [ 1 ] Gail Glendinning, Ted Perry, Bruce Remington, Jim Knauer, Tom Boehly, and other members of the NLUF Experimental Astrophysics Team. Publications: Reighard et al., Phys. Rev. Lett. submitted; Leibrandt, et al., Ap J., in press, Reighard et al., IFSA 03 Proceedings, Amer. Nucl. Soc. (2004). [2] Useful discussions with Dmitri Ryutov and Serge Bouquet. Supported by the NNSA programs via DOE Grants DE-FG52-03NA00064 and DE FG53 2005 NA26014

  8. Radiation- and pair-loaded shocks

    Science.gov (United States)

    Lyutikov, Maxim

    2018-06-01

    We consider the structure of mildly relativistic shocks in dense media, taking into account the radiation and pair loading, and diffusive radiation energy transfer within the flow. For increasing shock velocity (increasing post-shock temperature), the first important effect is the efficient energy redistribution by radiation within the shock that leads to the appearance of an isothermal jump, whereby the flow reaches the final state through a discontinuous isothermal transition. The isothermal jump, on scales much smaller than the photon diffusion length, consists of a weak shock and a quick relaxation to the isothermal conditions. Highly radiation-dominated shocks do not form isothermal jump. Pair production can mildly increase the overall shock compression ratio to ≈10 (4 for matter-dominated shocks and 7 of the radiation-dominated shocks).

  9. Nonrelativistic grey Sn-transport radiative-shock solutions

    International Nuclear Information System (INIS)

    Ferguson, J. M.; Morel, J. E.; Lowrie, R. B.

    2017-01-01

    We present semi-analytic radiative-shock solutions in which grey Sn-transport is used to model the radiation, and we include both constant cross sections and cross sections that depend on temperature and density. These new solutions solve for a variable Eddington factor (VEF) across the shock domain, which allows for interesting physics not seen before in radiative-shock solutions. Comparisons are made with the grey nonequilibrium-diffusion radiative-shock solutions of Lowrie and Edwards [1], which assumed that the Eddington factor is constant across the shock domain. It is our experience that the local Mach number is monotonic when producing nonequilibrium-diffusion solutions, but that this monotonicity may disappear while integrating the precursor region to produce Sn-transport solutions. For temperature- and density-dependent cross sections we show evidence of a spike in the VEF in the far upstream portion of the radiative-shock precursor. We show evidence of an adaptation zone in the precursor region, adjacent to the embedded hydrodynamic shock, as conjectured by Drake [2, 3], and also confirm his expectation that the precursor temperatures adjacent to the Zel’dovich spike take values that are greater than the downstream post-shock equilibrium temperature. We also show evidence that the radiation energy density can be nonmonotonic under the Zel’dovich spike, which is indicative of anti-diffusive radiation flow as predicted by McClarren and Drake [4]. We compare the angle dependence of the radiation flow for the Sn-transport and nonequilibriumdiffusion radiation solutions, and show that there are considerable differences in the radiation flow between these models across the shock structure. Lastly, we analyze the radiation flow to understand the cause of the adaptation zone, as well as the structure of the Sn-transport radiation-intensity solutions across the shock structure.

  10. Initial conditions of radiative shock experiments

    International Nuclear Information System (INIS)

    Kuranz, C. C.; Drake, R. P.; Krauland, C. M.; Marion, D. C.; Grosskopf, M. J.; Rutter, E.; Torralva, B.; Holloway, J. P.; Bingham, D.; Goh, J.; Boehly, T. R.; Sorce, A. T.

    2013-01-01

    We performed experiments at the Omega Laser Facility to characterize the initial, laser-driven state of a radiative shock experiment. These experiments aimed to measure the shock breakout time from a thin, laser-irradiated Be disk. The data are then used to inform a range of valid model parameters, such as electron flux limiter and polytropic γ, used when simulating radiative shock experiments using radiation hydrodynamics codes. The characterization experiment and the radiative shock experiment use a laser irradiance of ∼7 × 10 14 W cm −2 to launch a shock in the Be disk. A velocity interferometer and a streaked optical pyrometer were used to infer the amount of time for the shock to move through the Be disk. The experimental results were compared with simulation results from the Hyades code, which can be used to model the initial conditions of a radiative shock system using the CRASH code

  11. Monetary Shocks in Models with Inattentive Producers.

    Science.gov (United States)

    Alvarez, Fernando E; Lippi, Francesco; Paciello, Luigi

    2016-04-01

    We study models where prices respond slowly to shocks because firms are rationally inattentive. Producers must pay a cost to observe the determinants of the current profit maximizing price, and hence observe them infrequently. To generate large real effects of monetary shocks in such a model the time between observations must be long and/or highly volatile. Previous work on rational inattentiveness has allowed for observation intervals that are either constant-but-long ( e.g . Caballero, 1989 or Reis, 2006) or volatile-but-short ( e.g . Reis's, 2006 example where observation costs are negligible), but not both. In these models, the real effects of monetary policy are small for realistic values of the duration between observations. We show that non-negligible observation costs produce both of these effects: intervals between observations are infrequent and volatile. This generates large real effects of monetary policy for realistic values of the average time between observations.

  12. Radiation produced biomaterials

    International Nuclear Information System (INIS)

    Rosiak, J.M.

    1998-01-01

    radiation technique. Immobilization of biologically active species in hydrogel matrices, their use as drug delivery systems and enzyme traps as well as modification of material surfaces to improve their biocompatibility and ability to bond antigens and antibodies have been the main subject of their investigations. The rising interest in the field of application of radiation to bioengineering was also recognized by the International Atoimc Energy Agency, which has initiated the international programs relating to those studies. In these lectures some directions of investigations on the formation of hydrogels and their applications for biomedical purposes have been specified. Also, some examples of commercialized products being produced by means of radiation technique have been presented

  13. Radiative shocks with electron thermal conduction

    International Nuclear Information System (INIS)

    Borkowski, Kazimierz.

    1988-01-01

    The authors studies the influence of electron thermal conduction on radiative shock structure for both one- and two-temperature plasmas. The dimensionless ratio of the conductive length to the cooling length determines whether or not conduction is important, and shock jump conditions with conduction are established for a collisionless shock front. He obtains approximate solutions with the assumptions that the ionization state of the gas is constant and the cooling rate is a function of temperature alone. In the absence of magnetic fields, these solutions indicate that conduction noticeably influences normal-abundance interstellar shocks with velocities 50-100 km s -1 and dramatically affects metal-dominated shocks over a wide range of shock velocities. Magnetic fields inhibit conduction, but the conductive energy flux and the corresponding decrease in the post-shock electron temperature may still be appreciable. He calculates detailed steady-state radiative shock models in gas composed entirely of oxygen, with the purpose of explaining observations of fast-moving knots in Cas A and other oxygen-rich supernova remnants (SNRs). The O III ion, whose forbidden emission usually dominates the observed spectra, is present over a wide range of shock velocities, from 100 to 170 kms -1 . All models with conduction have extensive warm photoionization zones, which provides better agreement with observed optical (O I) line strengths. However, the temperatures in these zones could be lowered by (Si II) 34.8 μm and (Ne II) 12.8 μm cooling if Si and Ne are present in appreciable abundance relative to O. Such low temperatures would be inconsistent with the observed (O I) emission in oxygen-rich SNRs

  14. Radiating shocks and condensations in flares

    International Nuclear Information System (INIS)

    Fisher, G.H.

    1985-01-01

    Rapid energy release (by either ''thick target'' (beam) or ''thermal'' models of heating) in solar flare loop models usually leads to ''chromospheric evaporation,'' the process of heating cool chromospheric material to coronal temperatures, and the resulting increase in hot soft x-ray emitting plasma. The evaporated plasma flows up into the coronal portion of the loop because of the increased pressure in the evaporated region. However, the pressure increase also leads to a number of interesting phenomena in the flare chromosphere, which will be the subject of this paper. The sudden pressure increase in the evaporated plasma initiates a downward moving ''chromospheric condensation,'' an overdense region which gradually decelerates as it accretes material and propagates into the gravitationally stratified chromosphere. Solutions to an equation of motion for this condensation shows that its motion decays after about one minute of propagation into the chromosphere. When the front of this downflowing region is supersonic relative to the atmosphere ahead of it, a radiating shock will form. If the downflow is rapid enough, the shock strength should be sufficient to excite uv radiation normally associated with the transition region, and furthermore, the radiating shock will be brighter than the transition region. These results lead to a number of observationally testable relationships between the optical and ultraviolet spectra from the condensation and radiating shock

  15. Nonthermal Radiation from Supernova Remnant Shocks

    Directory of Open Access Journals (Sweden)

    Hyesung Kang

    2013-09-01

    Full Text Available Most of high energy cosmic rays (CRs are thought to be produced by diffusive shock acceleration (DSA at supernova remnants (SNRs within the Galaxy. Fortunately, nonthermal emissions from CR protons and electrons can provide direct observational evidence for such a model and place strong constraints on the complex nonlinear plasma processes in DSA theory. In this study we calculate the energy spectra of CR protons and electrons in Type Ia SNRs, using time-dependent DSA simulations that incorporate phenomenological models for some wave-particle interactions. We demonstrate that the timedependent evolution of the self-amplified magnetic fields, Alfvénic drift, and escape of the highest energy particles affect the energy spectra of accelerated protons and electrons, and so resulting nonthermal radiation spectrum. Especially, the spectral cutoffs in X-ray and γ-ray emission spectra are regulated by the evolution of the highest energy particles, which are injected at the early phase of SNRs. Thus detailed understandings of nonlinear wave-particle interactions and time-dependent DSA simulations of SNRs are crucial in testing the SNR hypothesis for the origin of Galactic cosmic rays.

  16. Effect of lateral radiative losses on radiative shock propagation

    Czech Academy of Sciences Publication Activity Database

    Busquet, M.; Audit, E.; González, M.; Stehlé, C.; Thais, F.; Acef, O.; Bauduin, D.; Barroso, P.; Rus, Bedřich; Kozlová, Michaela; Polan, Jiří; Mocek, Tomáš

    2007-01-01

    Roč. 3, - (2007), s. 8-11 ISSN 1574-1818 EU Projects: European Commission(XE) 506350 - LASERLAB-EUROPE Institutional research plan: CEZ:AV0Z10100523 Keywords : radiative shocks * laboratory astrophysics Subject RIV: BH - Optics, Masers, Lasers

  17. IRC -10414: a bow-shock-producing red supergiant star

    Science.gov (United States)

    Gvaramadze, V. V.; Menten, K. M.; Kniazev, A. Y.; Langer, N.; Mackey, J.; Kraus, A.; Meyer, D. M.-A.; Kamiński, T.

    2014-01-01

    Most runaway OB stars, like the majority of massive stars residing in their parent clusters, go through the red supergiant (RSG) phase during their lifetimes. Nonetheless, although many dozens of massive runaways were found to be associated with bow shocks, only two RSG bow-shock-producing stars, Betelgeuse and μ Cep, are known to date. In this paper, we report the discovery of an arc-like nebula around the late M-type star IRC -10414 using the SuperCOSMOS H-alpha Survey. Our spectroscopic follow-up of IRC -10414 with the Southern African Large Telescope (SALT) showed that it is a M7 supergiant, which supports previous claims on the RSG nature of this star based on observations of its maser emission. This was reinforced by our new radio- and (sub)millimetre-wavelength molecular line observations made with the Atacama Pathfinder Experiment 12-m telescope and the Effelsberg 100-m radio telescope, respectively. The SALT spectrum of the nebula indicates that its emission is the result of shock excitation. This finding along with the arc-like shape of the nebula and an estimate of the space velocity of IRC -10414 (≈70 ± 20 km s-1) imply the bow shock interpretation for the nebula. Thus, IRC -10414 represents the third case of a bow-shock-producing RSG and the first one with a bow shock visible at optical wavelengths. We discuss the smooth appearance of the bow shocks around IRC -10414 and Betelgeuse and propose that one of the necessary conditions for stability of bow shocks generated by RSGs is the ionization of the stellar wind. Possible ionization sources of the wind of IRC -10414 are proposed and discussed.

  18. Counterpropagating Radiative Shock Experiments on the Orion Laser.

    Science.gov (United States)

    Suzuki-Vidal, F; Clayson, T; Stehlé, C; Swadling, G F; Foster, J M; Skidmore, J; Graham, P; Burdiak, G C; Lebedev, S V; Chaulagain, U; Singh, R L; Gumbrell, E T; Patankar, S; Spindloe, C; Larour, J; Kozlova, M; Rodriguez, R; Gil, J M; Espinosa, G; Velarde, P; Danson, C

    2017-08-04

    We present new experiments to study the formation of radiative shocks and the interaction between two counterpropagating radiative shocks. The experiments are performed at the Orion laser facility, which is used to drive shocks in xenon inside large aspect ratio gas cells. The collision between the two shocks and their respective radiative precursors, combined with the formation of inherently three-dimensional shocks, provides a novel platform particularly suited for the benchmarking of numerical codes. The dynamics of the shocks before and after the collision are investigated using point-projection x-ray backlighting while, simultaneously, the electron density in the radiative precursor was measured via optical laser interferometry. Modeling of the experiments using the 2D radiation hydrodynamic codes nym and petra shows very good agreement with the experimental results.

  19. Radiation-mediated Shocks in Gamma-Ray Bursts: Pair Creation

    Science.gov (United States)

    Lundman, Christoffer; Beloborodov, Andrei M.; Vurm, Indrek

    2018-05-01

    Relativistic sub-photospheric shocks are a possible mechanism for producing prompt gamma-ray burst (GRB) emission. Such shocks are mediated by scattering of radiation. We introduce a time-dependent, special relativistic code which dynamically couples Monte Carlo radiative transfer to the flow hydrodynamics. The code also self-consistently follows electron–positron pair production in photon–photon collisions. We use the code to simulate shocks with properties relevant to GRBs. We focus on plane-parallel solutions, which are accurate deep below the photosphere. The shock generates a power-law photon spectrum through the first-order Fermi mechanism, extending upward from the typical upstream photon energy. Strong (high Mach number) shocks produce rising νF ν spectra. We observe that in non-relativistic shocks the spectrum extends to {E}\\max ∼ {m}e{v}2, where v is the speed difference between the upstream and downstream. In relativistic shocks the spectrum extends to energies E> 0.1 {m}e{c}2 where its slope softens due to Klein–Nishina effects. Shocks with Lorentz factors γ > 1.5 are prolific producers of electron–positron pairs, yielding hundreds of pairs per proton. The main effect of pairs is to reduce the shock width by a factor of ∼ {Z}+/- -1. Most pairs annihilate far downstream of the shock, and the radiation spectrum relaxes to a Wien distribution, reaching equilibrium with the plasma at a temperature determined by the shock jump conditions and the photon number per proton. We discuss the implications of our results for observations of radiation generated by sub-photospheric shocks.

  20. Ablative stabilization of Rayleigh-Taylor instabilities resulting from a laser-driven radiative shock

    Science.gov (United States)

    Huntington, C. M.; Shimony, A.; Trantham, M.; Kuranz, C. C.; Shvarts, D.; Di Stefano, C. A.; Doss, F. W.; Drake, R. P.; Flippo, K. A.; Kalantar, D. H.; Klein, S. R.; Kline, J. L.; MacLaren, S. A.; Malamud, G.; Miles, A. R.; Prisbrey, S. T.; Raman, K. S.; Remington, B. A.; Robey, H. F.; Wan, W. C.; Park, H.-S.

    2018-05-01

    The Rayleigh-Taylor (RT) instability is a common occurrence in nature, notably in astrophysical systems like supernovae, where it serves to mix the dense layers of the interior of an exploding star with the low-density stellar wind surrounding it, and in inertial confinement fusion experiments, where it mixes cooler materials with the central hot spot in an imploding capsule and stifles the desired nuclear reactions. In both of these examples, the radiative flux generated by strong shocks in the system may play a role in partially stabilizing RT instabilities. Here, we present experiments performed on the National Ignition Facility, designed to isolate and study the role of radiation and heat conduction from a shock front in the stabilization of hydrodynamic instabilities. By varying the laser power delivered to a shock-tube target with an embedded, unstable interface, the radiative fluxes generated at the shock front could be controlled. We observe decreased RT growth when the shock significantly heats the medium around it, in contrast to a system where the shock did not produce significant heating. Both systems are modeled with a modified set of buoyancy-drag equations accounting for ablative stabilization, and the experimental results are consistent with ablative stabilization when the shock is radiative. This result has important implications for our understanding of astrophysical radiative shocks and supernova radiative hydrodynamics [Kuranz et al., Nature Communications 9(1), 1564 (2018)].

  1. Numerical investigation on target implosions driven by radiation ablation and shock compression in dynamic hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Delong; Sun, Shunkai; Zhao, Yingkui; Ding, Ning; Wu, Jiming; Dai, Zihuan; Yin, Li; Zhang, Yang; Xue, Chuang [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China)

    2015-05-15

    In a dynamic hohlraum driven inertial confinement fusion (ICF) configuration, the target may experience two different kinds of implosions. One is driven by hohlraum radiation ablation, which is approximately symmetric at the equator and poles. The second is caused by the radiating shock produced in Z-pinch dynamic hohlraums, only taking place at the equator. To gain a symmetrical target implosion driven by radiation ablation and avoid asymmetric shock compression is a crucial issue in driving ICF using dynamic hohlraums. It is known that when the target is heated by hohlraum radiation, the ablated plasma will expand outward. The pressure in the shocked converter plasma qualitatively varies linearly with the material temperature. However, the ablation pressure in the ablated plasma varies with 3.5 power of the hohlraum radiation temperature. Therefore, as the hohlraum temperature increases, the ablation pressure will eventually exceed the shock pressure, and the expansion of the ablated plasma will obviously weaken the shock propagation and decrease its velocity after propagating into the ablator plasma. Consequently, longer time duration is provided for the symmetrical target implosion driven by radiation ablation. In this paper these processes are numerically investigated by changing drive currents or varying load parameters. The simulation results show that a critical hohlraum radiation temperature is needed to provide a high enough ablation pressure to decelerate the shock, thus providing long enough time duration for the symmetric fuel compression driven by radiation ablation.

  2. OBSERVATIONAL SIGNATURES OF SUB-PHOTOSPHERIC RADIATION-MEDIATED SHOCKS IN THE PROMPT PHASE OF GAMMA-RAY BURSTS

    International Nuclear Information System (INIS)

    Levinson, Amir

    2012-01-01

    A shock that forms below the photosphere of a gamma-ray burst (GRB) outflow is mediated by Compton scattering of radiation advected into the shock by the upstream fluid. The characteristic scale of such a shock, a few Thomson depths, is larger than any kinetic scale involved by several orders of magnitude. Hence, unlike collisionless shocks, radiation-mediated shocks cannot accelerate particles to nonthermal energies. The spectrum emitted by a shock that emerges from the photosphere of a GRB jet reflects the temperature profile downstream of the shock, with a possible contribution at the highest energies from the shock transition layer itself. We study the properties of radiation-mediated shocks that form during the prompt phase of GRBs and compute the time-integrated spectrum emitted by the shocked fluid following shock breakout. We show that the time-integrated emission from a single shock exhibits a prominent thermal peak, with the location of the peak depending on the shock velocity profile. We also point out that multiple shock emission can produce a spectrum that mimics a Band spectrum.

  3. Radiation processing of horticulture produce

    International Nuclear Information System (INIS)

    Khandal, R.K.

    2004-01-01

    The present paper deals with various aspects of radiation processing of horticultural products. The risk and success factors of the radiation processing units would be discussed, based on the experiences gained from the operation of Sac over a period of more than twenty years. Emphasis would be given to gamma radiation processing

  4. A radiating shock evaluated using Implicit Monte Carlo Diffusion

    International Nuclear Information System (INIS)

    Cleveland, M.; Gentile, N.

    2013-01-01

    Implicit Monte Carlo [1] (IMC) has been shown to be very expensive when used to evaluate a radiation field in opaque media. Implicit Monte Carlo Diffusion (IMD) [2], which evaluates a spatial discretized diffusion equation using a Monte Carlo algorithm, can be used to reduce the cost of evaluating the radiation field in opaque media [2]. This work couples IMD to the hydrodynamics equations to evaluate opaque diffusive radiating shocks. The Lowrie semi-analytic diffusive radiating shock benchmark[a] is used to verify our implementation of the coupled system of equations. (authors)

  5. Excitation of intense shock waves by soft X-radiation

    International Nuclear Information System (INIS)

    Branitskij, A.V.; Fortov, V.E.; Danilenko, K.N.; Dyabilin, K.S.; Grabovskij, E.V.; Vorobev, O. Yu.; Lebedev, M.E.; Smirnov, V.P.; Zakharov, A.E.; Persyantsev, I.V.

    1996-01-01

    Investigation of the shock waves generated by soft x radiation in Al, Sn, Fe, and Pb targets is reported. The soft x radiation was induced by the dynamic compression and heating of the cylindrical z-pinch plasma generated in the ANGARA-5-1 pulsed power machine. The temperature of the z-pinch plasma was as high as 60 - 120 eV, and the duration of the x-ray pulse reached 30 ns FWHM. Thick stepped Al/Pb, Sn/Pb, and pure Pb targets were used. The results of experiments show that uniform intense shock waves can be generated by z-pinch plasma soft x-ray radiation. The uniformity of the shock is very high. At a flux power of the order of several TW/cm 2 , a shock pressure of some hundreds of GPa was achieved. (J.U.). 3 figs., 11 refs

  6. Excitation of intense shock waves by soft X-radiation

    Energy Technology Data Exchange (ETDEWEB)

    Branitskij, A V; Fortov, V E; Danilenko, K N; Dyabilin, K S; Grabovskij, E V; Vorobev, O Yu; Lebedev, M E; Smirnov, V P; Zakharov, A E; Persyantsev, I V [Troitsk Inst. of Innovative and Fusion Research, Troitsk (Russian Federation)

    1997-12-31

    Investigation of the shock waves generated by soft x radiation in Al, Sn, Fe, and Pb targets is reported. The soft x radiation was induced by the dynamic compression and heating of the cylindrical z-pinch plasma generated in the ANGARA-5-1 pulsed power machine. The temperature of the z-pinch plasma was as high as 60 - 120 eV, and the duration of the x-ray pulse reached 30 ns FWHM. Thick stepped Al/Pb, Sn/Pb, and pure Pb targets were used. The results of experiments show that uniform intense shock waves can be generated by z-pinch plasma soft x-ray radiation. The uniformity of the shock is very high. At a flux power of the order of several TW/cm{sup 2}, a shock pressure of some hundreds of GPa was achieved. (J.U.). 3 figs., 11 refs.

  7. Hydrogen-Helium shock Radiation tests for Saturn Entry Probes

    Science.gov (United States)

    Cruden, Brett A.

    2016-01-01

    This paper describes the measurement of shock layer radiation in Hydrogen/Helium mixtures representative of that encountered by probes entering the Saturn atmosphere. Normal shock waves are measured in Hydrogen-Helium mixtures (89:11% by volume) at freestream pressures between 13-66 Pa (0.1-0.5 Torr) and velocities from 20-30 km/s. Radiance is quantified from the Vacuum Ultraviolet through Near Infrared. An induction time of several centimeters is observed where electron density and radiance remain well below equilibrium. Radiance is observed in front of the shock layer, the characteristics of which match the expected diffusion length of Hydrogen.

  8. The Radiation, Interplanetary Shocks, and Coronal Sources (RISCS) Toolset

    Science.gov (United States)

    Zank, G. P.; Spann, James F.

    2014-01-01

    The goal of this project is to serve the needs of space system designers and operators by developing an interplanetary radiation environment model within 10 AU:Radiation, Interplanetary Shocks, and Coronal Sources (RISCS) toolset: (1) The RISCS toolset will provide specific reference environments for space system designers and nowcasting and forecasting capabilities for space system operators; (2) We envision the RISCS toolset providing the spatial and temporal radiation environment external to the Earth's (and other planets') magnetosphere, as well as possessing the modularity to integrate separate applications (apps) that can map to specific magnetosphere locations and/or perform the subsequent radiation transport and dosimetry for a specific target.

  9. Astrophysical radiative shocks: From modeling to laboratory experiments

    Czech Academy of Sciences Publication Activity Database

    Gonzales, N.; Stehlé, C.; Audit, E.; Busquet, M.; Rus, Bedřich; Thais, F.; Acef, O.; Barroso, P.; Bar-Shalom, A.; Bauduin, D.; Kozlová, Michaela; Lery, T.; Madouri, A.; Mocek, Tomáš; Polan, Jiří

    2006-01-01

    Roč. 24, - (2006), s. 535-540 ISSN 0263-0346 EU Projects: European Commission(XE) 506350 - LASERLAB-EUROPE; European Commission(XE) 5592 - JETSET Grant - others:CNRS(FR) PNPS Institutional research plan: CEZ:AV0Z10100523 Keywords : laboratory astrophysics * laser plasmas * radiative shock waves * radiative transfer Subject RIV: BH - Optics, Masers, Lasers Impact factor: 3.958, year: 2006

  10. Particle Acceleration and Radiative Losses at Relativistic Shocks

    Science.gov (United States)

    Dempsey, P.; Duffy, P.

    A semi-analytic approach to the relativistic transport equation with isotropic diffusion and consistent radiative losses is presented. It is based on the eigenvalue method first introduced in Kirk & Schneider [5]and Heavens & Drury [3]. We demonstrate the pitch-angle dependence of the cut-off in relativistic shocks.

  11. Use of Z pinch radiation sources for high pressure shock wave studies

    International Nuclear Information System (INIS)

    Asay, J.R.; Konrad, C.H.; Hall, C.A.; Trott, W.M.; Chandler, G.A.; Holland, K.G.; Fleming, K.J.; Trucano, T.G.

    1998-01-01

    Recent developments in pulsed power technology demonstrate use of intense radiation sources (Z pinches) for driving planar shock waves in samples with spatial dimensions larger than possible with other radiation sources. Initial indications are that the use of Z pinch sources can be used to produce planar shock waves in samples with diameters of a few millimeters and thicknesses approaching one half millimeter. These dimensions allow increased accuracy of both shock velocity and particle velocity measurements. The Z pinch radiation source uses imploding metal plasma induced by self-magnetic fields applied to wire arrays to produce high temperature x-ray environments in vacuum hohlraum enclosures. Previous experiments have demonstrated that planar shock waves can be produced with this approach. A photograph of a wire array located inside the vacuum hohlraum is shown here. Typically, a few hundred individual wires are used to produce the Z pinch source. For the shock wave experiments being designed, arrays of 120 to 240 tungsten wires with a diameter of 40 mm and with individual diameters of about 10 microm are used. Preliminary experiments have been performed on the Z pulsed radiation source to demonstrate the ability to obtain VISAR measurements in the Z accelerator environment. Analysis of these results indicate that another effect, not initially anticipated, is an apparent change in refractive index that occurs in the various optical components used in the system. This effect results in an apparent shift in the frequency of reflected laser light, and causes an error in the measured particle velocity. Experiments are in progress to understand and minimize this effect

  12. Radiation exposure to patients during extracorporeal shock wave lithotripsy

    International Nuclear Information System (INIS)

    Van Swearingen, F.L.; McCullough, D.L.; Dyer, R.; Appel, B.

    1987-01-01

    Extracorporeal shock wave lithotripsy is rapidly becoming an accepted treatment of renal calculi. Since fluoroscopy is involved to image the stones it is important to know how much radiation the patient receives during this procedure. Surface radiation exposure to the patient was measured in more than 300 fluoroscopic and radiographic procedures using thermoluminescent dosimeters. Initial results showed an average skin exposure of 10.1 rad per procedure for each x-ray unit, comparing favorably with exposure rates for percutaneous nephrostolithotomy and other routine radiological procedures. Factors influencing exposure levels include stone characteristics (location, size and opacity), physician experience and number of shocks required. Suggestions are given that may result in a 50 per cent reduction of radiation exposure

  13. Diagnosing radiative shocks from deuterium and tritium implosions on NIF.

    Science.gov (United States)

    Pak, A; Divol, L; Weber, S; Döppner, T; Kyrala, G A; Kilne, J; Izumi, N; Glenn, S; Ma, T; Town, R P; Bradley, D K; Glenzer, S H

    2012-10-01

    During the recent ignition tuning campaign at the National Ignition Facility, layered cryogenic deuterium and tritium capsules were imploded via x-ray driven ablation. The hardened gated x-ray imager diagnostic temporally and spatially resolves the x-ray emission from the core of the capsule implosion at energies above ~8 keV. On multiple implosions, ~200-400 ps after peak compression a spherically expanding radiative shock has been observed. This paper describes the methods used to characterize the radial profile and rate of expansion of the shock induced x-ray emission.

  14. Comparisons of Air Radiation Model with Shock Tube Measurements

    Science.gov (United States)

    Bose, Deepak; McCorkle, Evan; Bogdanoff, David W.; Allen, Gary A., Jr.

    2009-01-01

    This paper presents an assessment of the predictive capability of shock layer radiation model appropriate for NASA s Orion Crew Exploration Vehicle lunar return entry. A detailed set of spectrally resolved radiation intensity comparisons are made with recently conducted tests in the Electric Arc Shock Tube (EAST) facility at NASA Ames Research Center. The spectral range spanned from vacuum ultraviolet wavelength of 115 nm to infrared wavelength of 1400 nm. The analysis is done for 9.5-10.5 km/s shock passing through room temperature synthetic air at 0.2, 0.3 and 0.7 Torr. The comparisons between model and measurements show discrepancies in the level of background continuum radiation and intensities of atomic lines. Impurities in the EAST facility in the form of carbon bearing species are also modeled to estimate the level of contaminants and their impact on the comparisons. The discrepancies, although large is some cases, exhibit order and consistency. A set of tests and analyses improvements are proposed as forward work plan in order to confirm or reject various proposed reasons for the observed discrepancies.

  15. Why does gravitational radiation produce vorticity?

    International Nuclear Information System (INIS)

    Herrera, L; Barreto, W; Carot, J; Prisco, A Di

    2007-01-01

    We calculate the vorticity of worldlines of observers at rest in a Bondi-Sachs frame, produced by gravitational radiation, in a general Sachs metric. We claim that such an effect is related to the super-Poynting vector, in a similar way as the existence of the electromagnetic Poynting vector is related to the vorticity in stationary electrovacuum spacetimes

  16. Radiation exposure to patients during extracorporeal shock wave lithotripsy

    International Nuclear Information System (INIS)

    Marti, J.M.; Robles, J.E.; Arbizu, J.; Castro, F. de; Berian, J.M.; Richter, J.A.

    1992-01-01

    We analyzed the radiological exposure to patients during Extracorporeal Shock Wave Lithotripsy (ESWL) using a second generator lithotriptor. Stone location is accomplished by fluoroscopy and 'quick pics' or snapshots. A prospective study over 55 patients showed a mean exposure of 32.2 R. The introduction of the ALARA criterion reduced it to 16.1 R in the following 145 patients. Mean radiation exposure to patient varies according to treatment difficulty. A mean increase of radiation exposure of 1.6 between low and high difficulty treatment groups was observed. This variation was about 96% when the physician who performed the treatment was considered. (author)

  17. Factors influencing radiation exposure during the extracorporeal shock wave lithotripsy

    Energy Technology Data Exchange (ETDEWEB)

    Wei Chuan Chen; Ying Huei Lee; Ming Tsun Chen; Jong Khing Huang; Luke S Chang (Division of Urology, Dept. of Surgery, National Yang-Ming Medical College and Veterans General Hospital-Taipei, Taiwan (China))

    1991-01-01

    A prospective evaluation of 89 consecutive sessions of extracorporeal shock wave lithotripsy (ESWL) was undertaken to try and find the best way of minimising the amount of exposure to radiation. Forty-two patients were randomly allocated to undergo ESWL treatment by experienced surgeons (group A), and 47 to undergo the treatment by inexperienced surgeons (group B). The mean calculated entrance radiation exposure was 3.01 rads (group A: 2.64 (0.97) rads, range 1.00-4.48, group B: 3.38 (0.86) rads, range 1.11-5.75). Among factors that influenced radiation exposure, the tissue: air ratio should be borne in mind and the level of skill in controlling movement of gantry was the most important in reducing the exposure to radiation. (au).

  18. Factors influencing radiation exposure during the extracorporeal shock wave lithotripsy

    International Nuclear Information System (INIS)

    Wei Chuan Chen; Ying Huei Lee; Ming Tsun Chen; Jong Khing Huang; Luke S Chang

    1991-01-01

    A prospective evaluation of 89 consecutive sessions of extracorporeal shock wave lithotripsy (ESWL) was undertaken to try and find the best way of minimising the amount of exposure to radiation. Forty-two patients were randomly allocated to undergo ESWL treatment by experienced surgeons (group A), and 47 to undergo the treatment by inexperienced surgeons (group B). The mean calculated entrance radiation exposure was 3.01 rads (group A: 2.64 (0.97) rads, range 1.00-4.48, group B: 3.38 (0.86) rads, range 1.11-5.75). Among factors that influenced radiation exposure, the tissue: air ratio should be borne in mind and the level of skill in controlling movement of gantry was the most important in reducing the exposure to radiation. (au)

  19. Reply on the comment of the paper "New probing techniques of radiative shocks"

    Science.gov (United States)

    Stehlé, Chantal; Kozlová, Michaela; Larour, Jean; Nejdl, Jaroslav; Suzuki-Vidal, Francisco; Cohen, Mathieu; Chaulagain, Uddhab P.; Champion, Norbert; Barroso, Patrice; Acef, Ouali; Delattre, Pierre-Alexandre; Dostál, Jan; Krus, Miroslav; Chièze, Jean-Pierre; Ibgui, Laurent

    2014-05-01

    Imaging the structure of a radiative shock is a challenging task as the high plasma densities produced need a short wavelength to penetrate the plasma, requiring highly sophisticated imaging techniques. In a recent paper (Stehlé et al., Opt. Commun. 285 (2012) 64-69 [1]) the feasibility of a novel imaging technique using an X-ray laser (XRL) at 21 nm with a pulse duration 0.15 ns was proved. The recorded image was attributed to a shock propagating with a velocity of ~60 km/s. This velocity is in agreement with measurements of the plasma self-emission using time and space resolved diode diagnostics, and also in qualitative agreement with 1D numerical simulations. However, due to the inhomogeneous reflectivity of the XUV imaging mirror and to the low number of XRL photons, the quality of the recorded image was insufficient to unambiguously identify the different shock regions. Thus, arguing an ad hoc spatial resolution of ~0.5 mm and a stepwise representation of the shock-piston system, the potential of the technique to observe a radiative precursor was contested (Busquet's comment (in press) [2]). In this reply we aim at clarifying different aspects of the experimental setup, spatial resolution and other questions raised in this comment in order to back up our findings together with their respective analysis and interpretations.

  20. Non-LTE radiating acoustic shocks and Ca II K2V bright points

    Science.gov (United States)

    Carlsson, Mats; Stein, Robert F.

    1992-01-01

    We present, for the first time, a self-consistent solution of the time-dependent 1D equations of non-LTE radiation hydrodynamics in solar chromospheric conditions. The vertical propagation of sinusoidal acoustic waves with periods of 30, 180, and 300 s is calculated. We find that departures from LTE and ionization recombination determine the temperature profiles of the shocks that develop. In LTE almost all the thermal energy goes into ionization, so the temperature rise is very small. In non-LTE, the finite transition rates delay the ionization to behind the shock front. The compression thus goes into thermal energy at the shock front leading to a high temperature amplitude. Further behind the shock front, the delayed ionization removes energy from the thermal pool, which reduces the temperature, producing a temperature spike. The 180 s waves reproduce the observed temporal changes in the calcium K line profiles quite well. The observed wing brightening pattern, the violet/red peak asymmetry and the observed line center behavior are all well reproduced. The short-period waves and the 5 minute period waves fail especially in reproducing the observed behavior of the wings.

  1. An investigation of the structure of plasma produced by reflected shock waves

    International Nuclear Information System (INIS)

    Phillips, M.G.R.; Pugatschew, A.A.

    1979-05-01

    Space and time resolved measurements of electron density and temperature have been made in the reflected-shock plasma produced by a Mach 20 incident shock wave propagating in argon at an initial pressure of 1.5 Torr. The peak electron density was found to decrease away from the reflecting wall in such a way that the plasma was fairly uniform at all times. Close to the reflecting wall (0.2 cm away) the measured peak electron density was close to (i.e. about 20% lower than) the predicted equilibrium value but further away (1.0 cm) it was lower by a factor 4. Possible reasons for this discrepancy are discussed. Calculations of reflected-shock plasma structure based on incident shock structure are only partially supported by available experimental evidence

  2. Anti-diffusive radiation flow in the cooling layer of a radiating shock

    International Nuclear Information System (INIS)

    McClarren, Ryan G.; Paul Drake, R.

    2010-01-01

    This paper shows that for systems with optically thin, hot layers, such as those that occur in radiating shocks, radiation will flow uphill: radiation will flow from low to high radiation energy density. These are systems in which the angular distribution of the radiation intensity changes rapidly in space, and in which the radiation in some region has a pancaked structure, whose effect on the mean intensity will be much larger than the effect on the scalar radiation pressure. The salient feature of the solution to the radiative transfer equation in these circumstances is that the gradient of the radiation energy density is in the same direction as the radiation flux, i.e. radiation energy is flowing uphill. Such an anti-diffusive flow of energy cannot be captured by a model where the spatial variation of the Eddington factor is not accounted for, as in flux-limited diffusion models or the P 1 equations. The qualitative difference between the two models leads to a monotonic mean intensity for the diffusion model whereas the transport mean intensity has a global maximum in the hot layer. Mathematical analysis shows that the discrepancy between the diffusion model and the transport solution is due to an approximation of exponential integrals using a simple exponential.

  3. The Impact of Commodity Price Shocks in a Major Producing Economy. The Case of Copper and Chile

    OpenAIRE

    Michael Pedersen

    2015-01-01

    The present study analyzes how copper price shocks affect macroeconomic variables in Chile, which is the largest producer in the world of this commodity. It is taken into account that shocks with different sources may have different impacts and a separation is made between supply, demand, and specific copper demand shocks. The empirical analysis is based on a structural VAR model, where shocks are identified by sign restrictions, i.e. restrictions are imposed on impulse-response functions. In...

  4. 2D RADIATION-HYDRODYNAMIC SIMULATIONS OF SUPERNOVA SHOCK BREAKOUT IN BIPOLAR EXPLOSIONS OF A BLUE SUPERGIANT PROGENITOR

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Akihiro; Maeda, Keiichi [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto, 606-8502 (Japan); Shigeyama, Toshikazu [Research Center for the Early Universe, School of Science, University of Tokyo, Bunkyo-ku, Tokyo, 113-0033 (Japan)

    2016-07-10

    A two-dimensional special relativistic radiation-hydrodynamics code is developed and applied to numerical simulations of supernova shock breakout in bipolar explosions of a blue supergiant. Our calculations successfully simulate the dynamical evolution of a blast wave in the star and its emergence from the surface. Results of the model with spherical energy deposition show a good agreement with previous simulations. Furthermore, we calculate several models with bipolar energy deposition and compare their results with the spherically symmetric model. The bolometric light curves of the shock breakout emission are calculated by a ray-tracing method. Our radiation-hydrodynamic models indicate that the early part of the shock breakout emission can be used to probe the geometry of the blast wave produced as a result of the gravitational collapse of the iron core.

  5. Some techniques and results from high-pressure shock-wave experiments utilizing the radiation from shocked transparent materials

    International Nuclear Information System (INIS)

    McQueen, R.G.; Fritz, J.N.

    1981-01-01

    It has been known for many years that some transparent materials emit radiation when shocked to high pressures. This property was used to determine the temperature of shocked fused and crystal quartz, which in turn allowed the thermal expansion of SiO 2 at high pressure and also the specific heat to be calculated. Once the radiative energy as a function of pressure is known for one material it is shown how this can be used to determine the temperature of other transparent materials. By the nature of the experiments very accurate shock velocities can be measured and hence high quality equation of state data obtained. Some techniques and results are presented on measuring sound velocities from symmetrical impact of nontransparent materials using radiation emitting transparent analyzers, and on nonsymmetrical impact experiments on transparent materials. Because of special requirements in the later experiments, techniques were developed that lead to very high-precision shock-wave data. Preliminary results, using these techniques are presented for making estimates of the melting region and the yield strength of some metals under strong shock conditions

  6. A semiquantitative theory for the 2fp radiation observed upstream from the earth's bow shock

    International Nuclear Information System (INIS)

    Cairns, I.H.

    1988-01-01

    A semiquantitative theory for the 2f p radiation observed upstream from the Earth's bow shock is presented: the radiation is produced by the process L + L → T + S, proceeding as two sequential three-wave steps L → L' + S and L + L' → T, in the foreshock where nonthermal L and S waves are observed. (Here L, S, and T denote Langmuir, ion acoustic, and transverse electromagnetic waves, respectively.) This theory is consistent with all the available wave data, including the characteristics and levels of a class of low-frequency waves identified as S wave products of the process L → L' + S, and the brightness temperature and bandwidth of the 2f p radiation. Indeed the theory could account for higher 2f p brightness temperatures if required. Predictions of the theory suitable for observational testing include (1) the existence of two 2f p sources, one to each wing of the foreshock, (2) the spatial location of the source regions, and (3) the characteristics and levels of the product L' and S waves in the source regions. The radiation should (4) have intrinsic bandwidths of the order of 1 kHz or less, (5) be less than 0.1% circularly polarized, and (6) have a limiting brightness temperature equal to the effective temperature T L of the L waves producing the radiation

  7. Dispersive shock mediated resonant radiations in defocused nonlinear medium

    Science.gov (United States)

    Bose, Surajit; Chattopadhyay, Rik; Bhadra, Shyamal Kumar

    2018-04-01

    We report the evolution of resonant radiation (RR) in a self-defocused nonlinear medium with two zero dispersion wavelengths. RR is generated from dispersive shock wave (DSW) front when the pump pulse is in non-solitonic regime close to first zero dispersion wavelength (ZDW). DSW is responsible for pulse splitting resulting in the generation of blue solitons when leading edge of the pump pulse hits the first ZDW. DSW also generates a red shifted dispersive wave (DW) in the presence of higher order dispersion coefficients. Further, DSW through cross-phase modulation with red shifted dispersive wave (DW) excites a localized radiation. The presence of zero nonlinearity point in the system restricts red-shift of RR and enhances the red shifting of DW. It also helps in the formation of DSW at shorter distance and squeezes the solitonic region beyond second zero dispersion point. Predicted results indicate that the spectral evolution depends on the product of Kerr nonlinearity and group velocity dispersion.

  8. Magnetogasdynamic spherical shock wave in a non-ideal gas under gravitational field with conductive and radiative heat fluxes

    Science.gov (United States)

    Nath, G.; Vishwakarma, J. P.

    2016-11-01

    Similarity solutions are obtained for the flow behind a spherical shock wave in a non-ideal gas under gravitational field with conductive and radiative heat fluxes, in the presence of a spatially decreasing azimuthal magnetic field. The shock wave is driven by a piston moving with time according to power law. The radiation is considered to be of the diffusion type for an optically thick grey gas model and the heat conduction is expressed in terms of Fourier's law for heat conduction. Similarity solutions exist only when the surrounding medium is of constant density. The gas is assumed to have infinite electrical conductivity and to obey a simplified van der Waals equation of state. It is shown that an increase of the gravitational parameter or the Alfven-Mach number or the parameter of the non-idealness of the gas decreases the compressibility of the gas in the flow-field behind the shock, and hence there is a decrease in the shock strength. The pressure and density vanish at the inner surface (piston) and hence a vacuum is formed at the center of symmetry. The shock waves in conducting non-ideal gas under gravitational field with conductive and radiative heat fluxes can be important for description of shocks in supernova explosions, in the study of a flare produced shock in the solar wind, central part of star burst galaxies, nuclear explosion etc. The solutions obtained can be used to interpret measurements carried out by space craft in the solar wind and in neighborhood of the Earth's magnetosphere.

  9. The pretective effects of heat shock protein 70 on radiation injury of V79 cells

    International Nuclear Information System (INIS)

    Qin Yongchun; Zhang Baoguo; Hong Chengjiao

    2008-01-01

    Westem blot was used to detect the expression of heat shock protein 70 in V79 cells after heat shock pretreatment; V79 cells were irradiated using γ-ray after heat shock pretreatment, survival rate was observed using Colony formation assay. Our study shows that 1) the overexpression of heat shock protein 70 was observed in cells recovering for 1 hour after heat shock pretreatment, with peak expression in cells recovering for 4 hours, and could last for 24 hours; 2) heat shock pretreatment was able to elevate survival rate of V79 cells after irradiation by 60 Co γ ray (when the irradiation dose was less than 6 Gy). The results indicate that heat shock protein 70 has protective effect on radiation induced cell death of V79 cells (when the irradiation dose was less than 6 Gy). (authors)

  10. Measurement of Radiative Non-Equilibrium for Air Shocks Between 7-9 Km/s

    Science.gov (United States)

    Cruden, Brett A.; Brandis, Aaron M.

    2016-01-01

    This paper describes a recent characterization of non-equilibrium radiation for shock speeds between 7 and 9 km/s in the NASA Ames Electric Arc Shock Tube (EAST) Facility. Data is spectrally resolved from 190- 1450 nm and spatially resolved behind the shock front. Comparisons are made to DPLR/NEQAIR simulations using different modeling options and recommendations for future study are made based on these comparisons.

  11. Simulations of radiative shocks and jet formation in laboratory plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Velarde, P; Gonzalez, M; GarcIa-Fernandez, C; Oliva, E [Instituto de Fusion Nuclear, Universidad Politcnica de Madrid, Madrid (Spain) (Spain); Kasperczuk, A; Pisarczyk, T [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland) (Poland); Ullschmied, J [Institute of Plasma Physics AS CR, Prague (Czech Republic) (Czech Republic); Stehle, C [LERMA, Observatoire de Paris, Meudon (France) (France); Rus, B [Institute of Physics, PALS Center, Prague (Czech Republic) (Czech Republic); GarcIa-Senz, D; Bravo, E; Relano, A [Departament de Fisica i Enginyeria Nuclear. Universitat Politecnica de Catalunya. Barcelona (Spain) (Spain)], E-mail: velarde@din.upm.es

    2008-05-01

    We present the simulations of two relevant hydrodynamical problems related to astrophysical phenomena performed by three different codes. The numerical results from these codes will be compared in order to test both the numerical method implemented inside them and the influence of the physical phenomena simulated by the codes. Under some conditions laser produced plasmas could be scaled to the typical conditions prevailing in astrophysical plasmas. Therefore, such similarity allows to use existing laser facilities and numerical codes suitable to a laser plasma regime, for studying astrophysical proccesses. The codes are the radiation fluid dynamic 2D ARWEN code and the 3D HERACLES, and, without radiation energy transport, a Smoothed-Particle Hydrodynamics (SPH) code. These codes use different numerical techniques and have overlapping range of application, from laser produced plasmas to astrophysical plasmas. We also present the first laser experiments obtaining cumulative jets with a velocity higher than 100 km/s.

  12. 1 D analysis of Radiative Shock damping by lateral radiative losses

    Science.gov (United States)

    Busquet, Michel; Audit, Edouard

    2008-11-01

    We have demonstrated the effect of the lateral radiative losses in radiative shocks propagative in layered quasi-planar atmospheres.[1,2] The damping of the precursor is sensitive to the fraction of self-emitted radiation reflected by the walls (called albedo) We have given recently an experimental determination of the wall albedo.[2] For parametric analysis of this effect, we implement lateral losses in the 1D hydro-rad code MULTI [3] and compared results with 2D simulations. [1] S.Leygnac, et al., Phys. Plasmas 13, 113301 (2006) [2] M.Busquet, et al, High Energy Density Plasmas 3, 8-11 (2007); M.Gonzalez, et al, Laser Part. Beams 24, 1-6 (2006) [3] Ramis et al, Comp. Phys. Comm., 49, 475 (1988)

  13. Radiation sources and methods for producing them

    International Nuclear Information System (INIS)

    Malson, H.A.; Moyer, S.E.; Honious, H.B.; Janzow, E.F.

    1979-01-01

    The radiation sources contain a substrate with an electrically conducting, non-radioactive metal surface, a layer of a metal isotope of the scandium group as well as a percentage of non-radioactive binding metal being coated on the surface by means of an electroplating method. Besides examples for β sources ( 147 Pm), γ sources ( 241 Am), and neutron sources ( 252 Cf) there is described an α-radiation source ( 241 Am, 244 Cu, 238 Pu) for smoke detectors. There are given extensive tables and a bibliography. (DG) [de

  14. Optical Spectroscopy Measurements of Shock Waves Driven by Intense Z-Pinch Radiation

    International Nuclear Information System (INIS)

    Asay, J.; Bernard, M.; Bailey, J.E.; Carlson, A.L.; Chandler, G.A.; Hall, C.A.; Hanson, D.; Johnston, R.; Lake, P.; Lawrence, J.

    1999-01-01

    Z-pinches created using the Z accelerator generate approximately220 TW, 1.7 MJ radiation pulses that heat large (approximately10 cm 3 ) hohlraums to 100-150 eV temperatures for times of order 10 nsec. We are performing experiments exploiting this intense radiation to drive shock waves for equation of state studies. The shock pressures are typically 1-10 Mbar with 10 nsec duration in 6-mm-diameter samples. In this paper we demonstrate the ability to perform optical spectroscopy measurements on shocked samples located in close proximity to the z-pinch. These experiments are particularly well suited to optical spectroscopy measurements because of the relatively large sample size and long duration. The optical emission is collected using fiber optics and recorded with a streaked spectrograph. Other diagnostics include VISAR and active shock breakout measurements of the shocked sample and a suite of diagnostics that characterize the radiation drive. Our near term goal is to use the spectral emission to obtain the temperature of the shocked material. Longer term objectives include the examination of deviations of the spectrum from blackbody, line emission from lower density regions, determination of kinetic processes in molecular systems, evaluation of phase transitions such as the onset of metalization in transparent materials, and characterization of the plasma formed when the shock exits the rear surface. An initial set of data illustrating both the potential and the challenge of these measurements is described

  15. Radiation produced by electrons incident on molecules

    International Nuclear Information System (INIS)

    Moehlman, G.R.

    1977-01-01

    The work described in this thesis deals with light intensity measurements of emission spectra (1850-9000 A) produced by a continuous or pulsed beam of monoenergetic electrons (0 - 2000 eV) incident on a variety of molecular gases like H 2 , D 2 , H 2 O, HCl, NH 3 and several hydrocarbons. The emission spectra are dominated by fluorescence from excited fragments produced via dissociative excitation, besides fluorescence from excited parent molecules themselves. The experimental results thus obtained are expressed in terms of emission cross sections and lifetimes

  16. Simulation of radiation in laser produced plasmas

    Science.gov (United States)

    Colombant, D. G.; Klapisch, M.; Deniz, A. V.; Weaver, J.; Schmitt, A.

    1999-11-01

    The radiation hydrodynamics code FAST1D(J.H.Gardner,A.J.Schmitt,J.P.Dahlburg,C.J.Pawley,S.E.Bodner,S.P.Obenschain,V.Serlin and Y.Aglitskiy,Phys. Plasmas,5,1935(1998)) was used directly (i.e. without postprocessor) to simulate radiation emitted from flat targets irradiated by the Nike laser, from 10^12 W/cm^2 to 10^13W/cm^2. We use enough photon groups to resolve spectral lines. Opacities are obtained from the STA code(A.Bar-Shalom,J.Oreg,M.Klapisch and T.Lehecka,Phys.Rev.E,59,3512(1999)), and non LTE effects are described with the Busquet model(M.Busquet,Phys.Fluids B,5,4191(1993)). Results are compared to transmission grating spectra in the range 100-600eV, and to time-resolved calibrated filtered diodes (spectral windows around 100, 180, 280 and 450 eV).

  17. Hybrid hydrogels produced by ionizing radiation technique

    Science.gov (United States)

    Oliveira, M. J. A.; Amato, V. S.; Lugão, A. B.; Parra, D. F.

    2012-09-01

    The interest in biocompatible hydrogels with particular properties has increased considerably in recent years due to their versatile applications in biomedicine, biotechnology, pharmacy, agriculture and controlled release of drugs. The use of hydrogels matrices for particular drug-release applications has been investigated with the synthesis of modified polymeric hydrogel of PVAl and 0.5, 1.0, 1.5% nano-clay. They were processed using gamma radiation from Cobalt-60 source at 25 kGy dose. The characterization of the hydrogels was conducted and toxicity was evaluated. The dried hydrogel was analyzed for thermogravimetry analysis (TGA), infrared spectroscopy (FTIR) and swelling in solutions of different pH. The membranes have no toxicity. The nano-clay influences directly the equilibrium swelling.

  18. Using Fast Hot Shock Wave Consolidation Technology to Produce Superconducting MgB2

    Directory of Open Access Journals (Sweden)

    T. Gegechkori

    2018-02-01

    Full Text Available The original hot shock wave assisted consolidation method combining high temperature was applied with the two-stage explosive process without any further sintering to produce superconducting materials with high density and integrity. The consolidation of MgB2 billets was performed at temperatures above the Mg melting point and up to 1000oC in partially liquid condition of Mg-2B blend powders. The influence of the type of boron (B isotope in the composition on critical temperature and superconductive properties was evaluated. An example of a hybrid Cu-MgB2–Cu superconducting tube is demonstrated and conclusions are discussed.

  19. Laboratory astrophysics with high energy and high power lasers: from radiative shocks to young star jets

    International Nuclear Information System (INIS)

    Diziere, A.

    2012-01-01

    Laboratory astrophysics are a rapidly developing domain of the High Energy Density Physics. It aims to recreate at smaller scales physical processes that astronomical telescopes have difficulties observing. We shall approach, in this thesis, three major subjects: 1) Jets ejected from young stars, characterized by an important collimation degree and ending with a bow shock; 2) Radiative shocks in which radiation emitted by the shock front itself plays a dominant role in its structure and 3) Accretion shocks in magnetic cataclysmic variables whose important cooling factor allows them to reach stationarity. From the conception to experimental realization, we shall attempt to reproduce in laboratory each of these processes by respecting the scaling laws linking both situations (experimental and astrophysical) established beforehand. The implementation of a large array of visible and X-ray diagnostics will finally allow to completely characterize them and calculate the dimensionless numbers that validate the astrophysical relevance. (author) [fr

  20. Hybrid hydrogels produced by ionizing radiation technique

    International Nuclear Information System (INIS)

    Oliveira, M.J.A.; Amato, V.S.; Lugão, A.B.; Parra, D.F.

    2012-01-01

    The interest in biocompatible hydrogels with particular properties has increased considerably in recent years due to their versatile applications in biomedicine, biotechnology, pharmacy, agriculture and controlled release of drugs. The use of hydrogels matrices for particular drug-release applications has been investigated with the synthesis of modified polymeric hydrogel of PVAl and 0.5, 1.0, 1.5% nano-clay. They were processed using gamma radiation from Cobalt-60 source at 25 kGy dose. The characterization of the hydrogels was conducted and toxicity was evaluated. The dried hydrogel was analyzed for thermogravimetry analysis (TGA), infrared spectroscopy (FTIR) and swelling in solutions of different pH. The membranes have no toxicity. The nano-clay influences directly the equilibrium swelling. - Highlights: ► Chemical interaction is observed when nanoclay is irradiated in PVAl hybrid hydrogels. ► Osmotic pressure within network promotes the rehydration capacity of the membranes. ► This effect is an important characteristic for hydrogels drug delivery systems.

  1. Effects produced by nuclear radiation in powdery milk

    International Nuclear Information System (INIS)

    Urena N, F.; Reyes G, A.

    1999-01-01

    The objective of this work is to determine the chemical effects produced by the gamma rays and beta particles radiations on the powdery milk. This work treats on the Pre-dose analysis, sampling radiating, electron spin resonance, acidity, proteins, aminoacids, lactose, fatty acids, peroxides, as well as its experimental results. (Author)

  2. CHARACTERISTICS OF THE SECONDARY BUBBLE CLUSTER PRODUCED BY AN ELECTROHYDRAULIC SHOCK WAVE LITHOTRIPTER

    Science.gov (United States)

    Zhou, Yufeng; Qin, Jun; Zhong, Pei

    2013-01-01

    This study investigated the characteristics of the secondary bubble cluster produced by an electrohydraulic lithotripter using high-speed imaging and passive cavitation detection techniques. The results showed that (i) the discrepancy of the collapse time between near a flat rigid boundary and in a free field of the secondary bubble cluster was not as significant as that by the primary one; (ii) the secondary bubble clusters were small but in a high bubble density and nonuniform in distribution, and they did not expand and aggregate significantly near a rigid boundary; and (iii) the corresponding bubble collapse was weaker with few microjet formation and bubble rebound. By applying a strong suction flow near the electrode tip, the production of the secondary shock wave (SW) and induced bubble cluster could be disturbed significantly, but without influence on the primary ones. Consequently, stone fragmentation efficiency was reduced from 41.2 ± 7.1% to 32.2 ± 3.5% after 250 shocks (p <0.05). Altogether, these observations suggest that the secondary bubble cluster produced by an electrohydraulic lithotripter may contribute to its ability for effective stone fragmentation. PMID:22390990

  3. Radiation Protection Practices of Staff during Extra-Corporeal Shock ...

    African Journals Online (AJOL)

    Methodology: Some members of staff who were present when the extra-corporeal shock wave lithotripsy (ESWL) was used in the hospital at Okada were interviewed between November 2002 and August 2003. Radiology records of the hospital were studied. Literature search involved available publication on the procedure ...

  4. What is radiation and how is it produced

    International Nuclear Information System (INIS)

    Edwards, M.

    1984-01-01

    In summary, a short answer to the question posed by the title of this chapter may be attempted in the following manner. Radiation is electromagnetic or particulate energy emitted or produced as the consequence of electron motion, radioactive decay, or atomic and nuclear interactions. Ionizing radiation is that radiation having sufficient energy to produce positive and negative charges directly or indirectly when it interacts with matter. As with many ''simple'' definitions of complex subjects, this definition contains many terms equally, if not more, complex than the one it purports to define. Like the aroma a good meal, it conveys a feeling for the subject that should stimulate, rather than satisfy, the appetite

  5. Astrophysically relevant radiatively cooled hypersonic bow shocks in nested wire arrays

    Science.gov (United States)

    Ampleford, David

    2009-11-01

    We have performed laboratory experiments which introduce obstructions into hypersonic plasma flows to study the formation of shocks. Astrophysical observations have demonstrated many examples of equivalent radiatively cooled bow shocks, for example the head of protostellar jets or supernova remnants passing through the interstellar medium or between discrete clumps in jets. Wire array z-pinches allow us to study quasi-planar radiatively cooled flows in the laboratory. The early stage of a wire array z-pinch implosion consists of a steady flow of the wire material towards the axis. Given a high rate of radiative cooling, these flows reach high sonic- Mach numbers, typically up to 5. The 2D nature of this configuration allows the insertion of obstacles into the flow, such as a concentric ``inner'' wire array, as has previously been studied for ICF research. Here we study the application of such a nested array to laboratory astrophysics where the inner wires act as obstructions perpendicular to the flow, and induce bow shocks. By varying the wire array material (W/Al), the significance of radiative cooling on these shocks can be controlled, and is shown to change the shock opening angle. As multiple obstructions are present, the experiments show the interaction of multiple bow shocks. It is also possible to introduce a magnetic field around the static object, increasing the opening angle of the shocks. Further experiments can be designed to control the flow density, magnetic field structure and obstruction locations. In collaboration with: S.V. Lebedev, M.E. Cuneo, C.A. Jennings, S.N. Bland, J.P. Chittenden, A. Ciardi, G.N. Hall, S.C. Bott, M. Sherlock, A. Frank, E. Blackman

  6. Method for producing bonded nonwoven fabrics using ionizing radiation

    International Nuclear Information System (INIS)

    Drelich, A.H.; Oney, D.G.

    1979-01-01

    A method is described for producing a resin-bonded nonwoven fabric. The preparation involves forming a fibrous web annealing it and compressing it to provide fiber to fiber contact. A polymerizable binder is applied to the fibrous web which is then treated by ionizing radiation to produce the material. 9 figures, 3 drawing

  7. SUB-PHOTOSPHERIC EMISSION FROM RELATIVISTIC RADIATION MEDIATED SHOCKS IN GRBs

    International Nuclear Information System (INIS)

    Bromberg, Omer; Mikolitzky, Ziv; Levinson, Amir

    2011-01-01

    It is proposed that the prompt emission observed in bursts that exhibit a thermal component originates from relativistic radiation mediated shocks (RRMS) that form below the photosphere of the gamma-ray burst (GRB) outflow. It is argued that such shocks are expected to form in luminous bursts via collisions of shells that propagate with moderate Lorentz factors Γ ∼< 500. Faster shells will collide above the photosphere to form collisionless shocks. We demonstrate that in events like GRB 090902B a substantial fraction of the explosion energy is dissipated below the photosphere, in a region of moderate optical depth τ ∼< 300, whereas in GRB 080916C the major fraction of the energy dissipates above the photosphere. We show that under conditions anticipated in many GRBs, such RRMS convect enough radiation upstream to render photon production in the shock transition negligible, unlike the case of shock breakout in supernovae. The resulting spectrum, as measured in the shock frame, has a relatively low thermal peak, followed by a broad, nonthermal component extending up to the Klein-Nishina limit.

  8. Theory for the radiation at the third to fifth harmonics of the plasma frequency upstream from the Earth's bow shock

    International Nuclear Information System (INIS)

    Cairns, I.H.

    1988-01-01

    A theory is presented for the radiation at the third to fifth harmonics of the plasma frequency observed upstream from the Earth's bow shock: the radiation is produced by the process L+T'→T in the foreshock, with the initial T' radiation being the frequently observed second harmonic radiation (generated by another process) and the L waves being products of the decay L'→L+S of L' waves generated by a streaming instability. (Here L, S, and T denote Langmuir, ion acoustic, and 'transverse electromagnetic waves, respectively.) The theory can account for the observed radiation when unusually large levels (electric fields in excess of 10 mV/m) of suitable L waves are present. Such levels of L waves are possible, in principle, but have not been reported before; the radiation is observed quite infrequently, thereby implying a requirement for unusual foreshock conditions. Predictions for the characteristics of the source regions (one to each wing of the foreshock) and the bandwidth of the radiation are given. Potential problems for the theory, relating to the large levels of L waves required to account for the radiation, are discussed. copyright American Geophysical Union 1988

  9. Heat Shock Protein 47: A Novel Biomarker of Phenotypically Altered Collagen-Producing Cells

    International Nuclear Information System (INIS)

    Taguchi, Takashi; Nazneen, Arifa; Al-Shihri, Abdulmonem A.; Turkistani, Khadijah A.; Razzaque, Mohammed S.

    2011-01-01

    Heat shock protein 47 (HSP47) is a collagen-specific molecular chaperone that helps the molecular maturation of various types of collagens. A close association between increased expression of HSP47 and the excessive accumulation of collagens is found in various human and experimental fibrotic diseases. Increased levels of HSP47 in fibrotic diseases are thought to assist in the increased assembly of procollagen, and thereby contribute to the excessive deposition of collagens in fibrotic areas. Currently, there is not a good universal histological marker to identify collagen-producing cells. Identifying phenotypically altered collagen-producing cells is essential for the development of cell-based therapies to reduce the progression of fibrotic diseases. Since HSP47 has a single substrate, which is collagen, the HSP47 cellular expression provides a novel universal biomarker to identify phenotypically altered collagen-producing cells during wound healing and fibrosis. In this brief article, we explained why HSP47 could be used as a universal marker for identifying phenotypically altered collagen-producing cells

  10. Crystalline and amorphous carbon nitride films produced by high-energy shock plasma deposition

    International Nuclear Information System (INIS)

    Bursilll, L.A.; Peng, Julin; Gurarie, V.N.; Orlov, A.V.; Prawer, S.

    1995-01-01

    High-energy shock plasma deposition techniques are used to produce carbon-nitride films containing both crystalline and amorphous components. The structures are examined by high-resolution transmission electron microscopy, parallel-electron-energy loss spectroscopy and electron diffraction. The crystalline phase appears to be face-centered cubic with unit cell parameter approx. a=0.63nm and it may be stabilized by calcium and oxygen at about 1-2 at % levels. The carbon atoms appear to have both trigonal and tetrahedral bonding for the crystalline phase. There is PEELS evidence that a significant fraction of the nitrogen atoms have sp 2 trigonal bonds in the crystalline phase. The amorphous carbon-nitride film component varies from essentially graphite, containing virtually no nitrogen, to amorphous carbon-nitride containing up to 10 at % N, where the fraction of sp 3 bonds is significant. 15 refs., 5 figs

  11. Planar radiative shock experiments and their comparison to simulations

    International Nuclear Information System (INIS)

    Reighard, A. B.; Drake, R. P.; Mucino, J. E.; Knauer, J. P.; Busquet, M.

    2007-01-01

    Recent experiments have obtained radiographic data from shock waves driven at >100 km/s in xenon gas, and Thomson scattering data from similar experiments using argon gas. Presented here is a review of these experiments, followed by an outline of the discrepancies between the data and the results of one-dimensional simulations. Simulations using procedures that work well for similar but nonradiative experiments show inconsistencies between the measured position of the interface of the beryllium and xenon and the calculated position for these experiments. Sources of the discrepancy are explored

  12. Experimental study of radiative shocks at PALS facility

    Czech Academy of Sciences Publication Activity Database

    Stehlé, C.; Gonzalez, M.; Kozlová, Michaela; Rus, Bedřich; Mocek, Tomáš; Acef, O.; Colombier, J.P.; Lanz, T.; Champion, N.; Jakubczak, Krzysztof; Polan, Jiří; Barroso, P.; Baudin, D.; Audit, E.; Dostál, Jan; Stupka, Michal

    2010-01-01

    Roč. 28, č. 2 (2010), s. 253-261 ISSN 0263-0346 R&D Projects: GA MŠk(CZ) LC528 Institutional research plan: CEZ:AV0Z10100523 Keywords : laboratory astrophysics * hydrodynamics * laser plasmas * shocks * stellar formation Subject RIV: BH - Optics, Masers, Lasers Impact factor: 3.656, year: 2010 http://journals.cambridge.org/action/displayFulltext?type=6&fid=7807203&jid=LPB&volumeId=28&issueId=02&aid=7807202&fulltextType=RA&fileId=S02630346100

  13. Nonequilibrium radiation behind a strong shock wave in CO{sub 2}-N{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Rond, C. [Universite de Provence - IUSTI, 5 rue Enrico Fermi, Marseille 13013 (France)], E-mail: rond@coria.fr; Boubert, P.; Felio, J.-M.; Chikhaoui, A. [Universite de Provence - IUSTI, 5 rue Enrico Fermi, Marseille 13013 (France)

    2007-11-09

    This work presents experiments reproducing plasma re-entry for one trajectory point of a Martian mission. The typical facility to investigate such hypersonic flow is shock tube; here we used the free-piston shock tube TCM2. Measurements of radiative flux behind the shock wave are realized thanks to time-resolved emission spectroscopy which is calibrated in intensity. As CN violet system is the main radiator in near UV-visible range, we have focused our study on its spectrum. Moreover a physical model, based on a multi-temperature kinetic code and a radiative code, for calculation of non equilibrium radiation behind a shock wave is developed for CO{sub 2}-N{sub 2}-Ar mixtures. Comparisons between experiments and calculations show that standard kinetic models (Park, McKenzie) are inefficient to reproduce our experimental results. Therefore we propose new rate coefficients in particular for the dissociation of CO{sub 2}, showing the way towards a better description of the chemistry of the mixture.

  14. Nonequilibrium radiation behind a strong shock wave in CO 2-N 2

    Science.gov (United States)

    Rond, C.; Boubert, P.; Félio, J.-M.; Chikhaoui, A.

    2007-11-01

    This work presents experiments reproducing plasma re-entry for one trajectory point of a Martian mission. The typical facility to investigate such hypersonic flow is shock tube; here we used the free-piston shock tube TCM2. Measurements of radiative flux behind the shock wave are realized thanks to time-resolved emission spectroscopy which is calibrated in intensity. As CN violet system is the main radiator in near UV-visible range, we have focused our study on its spectrum. Moreover a physical model, based on a multi-temperature kinetic code and a radiative code, for calculation of non equilibrium radiation behind a shock wave is developed for CO 2-N 2-Ar mixtures. Comparisons between experiments and calculations show that standard kinetic models (Park, McKenzie) are inefficient to reproduce our experimental results. Therefore we propose new rate coefficients in particular for the dissociation of CO 2, showing the way towards a better description of the chemistry of the mixture.

  15. Fabrication and Characterization of Targets for Shock Propagation and Radiation Burnthrough Measurements on Be-0.9 AT. % Cu Alloy

    International Nuclear Information System (INIS)

    Nobile, A.; Dropinski, S.C.; Edwards, J.M.; Rivera, G.; Margevicius, R.W.; Sebring, R.J.; Olson, R. E.; Tanner, D.L.

    2004-01-01

    Beryllium-copper alloy (Be0.9%Cu) ICF capsules are being developed for the pursuit of thermonuclear ignition at the National Ignition Facility (NIF). Success of this capsule material requires that its shock propagation and radiation burnthrough characteristics be accurately understood. To this end, experiments are being conducted to measure the shock propagation and radiation burnthrough properties of Be0.9%Cu alloy. These experiments involve measurements on small Be0.9%Cu wedge, step and flat samples. Samples are mounted on 1.6-mm-diameter x 1.2-mm-length hohlraums that are illuminated by the OMEGA laser at the University of Rochester. X-rays produced by the hohlraum drive the sample. A streaked optical pyrometer detects breakout of the shock produced by the X-ray pulse. In this paper we describe synthesis of the alloy material, fabrication and characterization of samples, and assembly of the targets. Samples were produced from Be0.9%Cu alloy that was synthesized by hot isostatic pressing of Be powder and copper flake. Samples were 850 μm diameter disks with varying thickness in the case of wedge and step samples, and uniform thickness in the case of flat samples. Sample thickness varied in the range 10-90 μm. Samples were prepared by precision lathe machining and electric discharge machining. The samples were characterized by a Veeco white light interferometer and an optical thickness measurement device that simultaneously measured the upper and lower surface contours of samples using two confocal laser probes. Several campaigns with these samples have been conducted over the past two years

  16. Studies on the propagation of relativistic plasma waves in high density plasmas produced by hypersonic ionizing shock waves

    International Nuclear Information System (INIS)

    Williams, R.L.; Johnson, J.A. III

    1993-01-01

    The feasibility of using an ionizing shock wave to produce high density plasmas suitable for the propagation large amplitude relativistic plasma waves is being investigated. A 20 kv arc driven shock tube of coaxial geometry produces a hypersonic shock wave (10 p > 10 17 cm -3 ). The shock can be made to reflect off the end of the tube, collide with its wake, and thus increase the plasma density further. After reflecting, the plasma is at rest. The shock speed is measured using piezoelectric pressure probes and the ion density is measured using laser induced fluorescence (LIF) techniques on argon 488.0 nm and 422.8 nm lines. The future plans are to excite large amplitude relativistic plasma waves in this plasma by either injecting a short pulse laser (Laser Wake Field Scheme), two beating lasers (Plasma Beat Wave Scheme), or a short bunch of relativistic electrons (Plasma Wake Field Scheme). Results of recent computational and theoretical studies, as well as initial experimental measurements on the plasma using LIF, are reported. Implications for the application of high density plasmas produced in this way to such novel schemes as the plasma wave accelerator, photon accelerator, plasma wave undulator, and also plasma lens, are discussed. The effect of plasma turbulence is also discussed

  17. High level compressive residual stresses produced in aluminum alloys by laser shock processing

    International Nuclear Information System (INIS)

    Gomez-Rosas, G.; Rubio-Gonzalez, C.; Ocana, J.L; Molpeceres, C.; Porro, J.A.; Chi-Moreno, W.; Morales, M.

    2005-01-01

    Laser shock processing (LSP) has been proposed as a competitive alternative technology to classical treatments for improving fatigue and wear resistance of metals. We present a configuration and results for metal surface treatments in underwater laser irradiation at 1064 nm. A convergent lens is used to deliver 1.2 J/cm 2 in a 8 ns laser FWHM pulse produced by 10 Hz Q-switched Nd:YAG, two laser spot diameters were used: 0.8 and 1.5 mm. Results using pulse densities of 2500 pulses/cm 2 in 6061-T6 aluminum samples and 5000 pulses/cm 2 in 2024 aluminum samples are presented. High level of compressive residual stresses are produced -1600 MPa for 6061-T6 Al alloy, and -1400 MPa for 2024 Al alloy. It has been shown that surface residual stress level is higher than that achieved by conventional shot peening and with greater depths. This method can be applied to surface treatment of final metal products

  18. Variables influencing radiation exposure during extracorporeal shock wave lithotripsy. Review of 298 treatments

    International Nuclear Information System (INIS)

    Carter, H.B.; Naeslund, E.B.R.; Riehle, R.A. Jr.

    1987-01-01

    Retrospective review of 298 extracorporeal shock wave lithotripsy (ESWL) treatments was undertaken to determine the factors which influence radiation exposure during ESWL. Fluoroscopy time averaged 160 seconds (3-509), and the average number of spot films taken per patient was 26 (5-68). The average stone burden was 19.3 mm (3-64). Average calculated skin surface radiation exposure was 17.8 R per treatment. Radiation exposure increased with increasing stone burden and patient weight. Stones treated in the ureter resulted in a higher average patient radiation exposure than for renal stones (19 R vs 16 R), even though the average size of these ureteral stones (11.3 mm) was significantly less than the mean. However, type of anesthetic (general or regional) used was not a significant factor. Operator training, experience, and familiarity with radiation physics should significantly decrease the amount of imaging time and consequent patient radiation exposure during ESWL

  19. Variables influencing radiation exposure during extracorporeal shock wave lithotripsy. Review of 298 treatments

    Energy Technology Data Exchange (ETDEWEB)

    Carter, H.B.; Naeslund, E.B.R.; Riehle, R.A. Jr.

    1987-12-01

    Retrospective review of 298 extracorporeal shock wave lithotripsy (ESWL) treatments was undertaken to determine the factors which influence radiation exposure during ESWL. Fluoroscopy time averaged 160 seconds (3-509), and the average number of spot films taken per patient was 26 (5-68). The average stone burden was 19.3 mm (3-64). Average calculated skin surface radiation exposure was 17.8 R per treatment. Radiation exposure increased with increasing stone burden and patient weight. Stones treated in the ureter resulted in a higher average patient radiation exposure than for renal stones (19 R vs 16 R), even though the average size of these ureteral stones (11.3 mm) was significantly less than the mean. However, type of anesthetic (general or regional) used was not a significant factor. Operator training, experience, and familiarity with radiation physics should significantly decrease the amount of imaging time and consequent patient radiation exposure during ESWL.

  20. On physical and numerical instabilities arising in simulations of non-stationary radiatively cooling shocks

    Science.gov (United States)

    Badjin, D. A.; Glazyrin, S. I.; Manukovskiy, K. V.; Blinnikov, S. I.

    2016-06-01

    We describe our modelling of the radiatively cooling shocks and their thin shells with various numerical tools in different physical and calculational setups. We inspect structure of the dense shell, its formation and evolution, pointing out physical and numerical factors that sustain its shape and also may lead to instabilities. We have found that under certain physical conditions, the circular shaped shells show a strong bending instability and successive fragmentation on Cartesian grids soon after their formation, while remain almost unperturbed when simulated on polar meshes. We explain this by physical Rayleigh-Taylor-like instabilities triggered by corrugation of the dense shell surfaces by numerical noise. Conditions for these instabilities follow from both the shell structure itself and from episodes of transient acceleration during re-establishing of dynamical pressure balance after sudden radiative cooling onset. They are also easily excited by physical perturbations of the ambient medium. The widely mentioned non-linear thin shell instability, in contrast, in tests with physical perturbations is shown to have only limited chances to develop in real radiative shocks, as it seems to require a special spatial arrangement of fluctuations to be excited efficiently. The described phenomena also set new requirements on further simulations of the radiatively cooling shocks in order to be physically correct and free of numerical artefacts.

  1. High-energy Emission from Nonrelativistic Radiative Shocks: Application to Gamma-Ray Novae

    Science.gov (United States)

    Vurm, Indrek; Metzger, Brian D.

    2018-01-01

    The observation of GeV gamma-rays from novae by Fermi/LAT demonstrates that the nonrelativistic radiative shocks in these systems can accelerate particles to energies of at least ∼10 GeV. The low-energy extension of the same nonthermal particle distribution inevitably gives rise to emission in the hard X-ray band. Above ≳ 10 {keV}, this radiation can escape the system without significant absorption/attenuation, and can potentially be detected by NuSTAR. We present theoretical models for hard X-ray and gamma-ray emission from radiative shocks in both leptonic and hadronic scenarios, accounting for the rapid evolution of the downstream properties due to the fast cooling of thermal plasma. We find that due to strong Coulomb losses, only a fraction of {10}-4{--}{10}-3 of the gamma-ray luminosity is radiated in the NuSTAR band; nevertheless, this emission could be detectable simultaneously with the LAT emission in bright gamma-ray novae with a ∼50 ks exposure. The spectral slope in hard X-rays is α ≈ 0 for typical nova parameters, thus serving as a testable prediction of the model. Our work demonstrates how combined hard X-ray and gamma-ray observations can be used to constrain properties of the nova outflow (velocity, density, and mass outflow rate) and particle acceleration at the shock. A very low X-ray to gamma-ray luminosity ratio ({L}{{X}}/{L}γ ≲ 5× {10}-4) would disfavor leptonic models for the gamma-ray emission. Our model can also be applied to other astrophysical environments with radiative shocks, including SNe IIn and colliding winds in massive star binaries.

  2. Generation of scaled protogalactic seed magnetic fields in laser-produced shock waves.

    Science.gov (United States)

    Gregori, G; Ravasio, A; Murphy, C D; Schaar, K; Baird, A; Bell, A R; Benuzzi-Mounaix, A; Bingham, R; Constantin, C; Drake, R P; Edwards, M; Everson, E T; Gregory, C D; Kuramitsu, Y; Lau, W; Mithen, J; Niemann, C; Park, H-S; Remington, B A; Reville, B; Robinson, A P L; Ryutov, D D; Sakawa, Y; Yang, S; Woolsey, N C; Koenig, M; Miniati, F

    2012-01-25

    The standard model for the origin of galactic magnetic fields is through the amplification of seed fields via dynamo or turbulent processes to the level consistent with present observations. Although other mechanisms may also operate, currents from misaligned pressure and temperature gradients (the Biermann battery process) inevitably accompany the formation of galaxies in the absence of a primordial field. Driven by geometrical asymmetries in shocks associated with the collapse of protogalactic structures, the Biermann battery is believed to generate tiny seed fields to a level of about 10(-21) gauss (refs 7, 8). With the advent of high-power laser systems in the past two decades, a new area of research has opened in which, using simple scaling relations, astrophysical environments can effectively be reproduced in the laboratory. Here we report the results of an experiment that produced seed magnetic fields by the Biermann battery effect. We show that these results can be scaled to the intergalactic medium, where turbulence, acting on timescales of around 700 million years, can amplify the seed fields sufficiently to affect galaxy evolution.

  3. Is gut the "motor" for producing hepatocellular dysfunction after trauma and hemorrhagic shock?

    Science.gov (United States)

    Wang, P; Ba, Z F; Cioffi, W G; Bland, K I; Chaudry, I H

    1998-02-01

    Although studies suggest that the gut may be the "motor" responsible for producing sepsis and multiple organ failure after injury, it is not known whether enterectomy prior to the onset of hemorrhage alters proinflammatory cytokines TNF and IL-6 and, if so, whether hepatocellular dysfunction and damage are prevented or attenuated under such conditions. Under methoxyflurane anesthesia, an enterectomy in the rat was performed by excision of the duodenum, jejunum, and ileum. The rats were then bled to and maintained at a mean arterial pressure of 40 mm Hg until 40% of the maximal shed volume was returned in the form of Ringer's lactate. The animals were then resuscitated with four times the volume of shed blood with Ringer's lactate over 1 h. At 1.5 h after the completion of resuscitation, hepatocellular function [i.e., the maximal velocity (Vmax) and transport efficiency (Km) of indocyanine green (ICG) clearance] was assessed by an in vivo ICG clearance technique. Blood samples were taken for the measurement of TNF, IL-6, and liver enzymes (i.e., SGPT and SGOT). Cardiac output and microvascular blood flow were determined by ICG dilution and laser Doppler flowmetry, respectively. The increase in circulating levels of TNF but not IL-6 was prevented by enterectomy prior to hemorrhage. The reduced Vmax and K(m) and elevated SGPT and SGOT following hemorrhage and resuscitation, however, were not significantly affected by prior enterectomy. Moreover, enterectomy before hemorrhage further reduced hepatic perfusion. Since enterectomy prior to the onset of hemorrhage does not prevent or attenuate the reduced ICG clearance and elevated liver enzymes despite downregulation of TNF production, it appears that the small intestine does not play a significant role in producing hepatocellular dysfunction and injury following trauma and hemorrhagic shock.

  4. Propagation of a shock wave in a radiating spherically symmetric distribution of matter

    International Nuclear Information System (INIS)

    Herrera, L.; Nunez, L.; Universidad de Los Andes, Merida, Venezuela)

    1987-01-01

    A method used to study the evolution of radiating spheres reported by Herrera et al. (1980) is extended to the case in which the sphere is divided in two regions by a shock wave front. The equations of state at both sides of the shock are different, and the solutions are matched on it via the Rankine-Hugoniot conditions. The outer-region metric is matched with a Vaidya solution on the boundary surface of the sphere. As an example of the procedure, two known solutions for radiating systems are considered. The matter distribution is free of singularities everywhere within the sphere and a Gaussian-like pulse is assumed to carry out a fraction of the total mass. Exploding models are then obtained. Finally, the results are discussed in the light of recent work on gravitational collapse and supernovae. 29 references

  5. Resonance Raman Spectroscopy of Free Radicals Produced by Ionizing Radiation

    DEFF Research Database (Denmark)

    Wilbrandt, Robert Walter

    1984-01-01

    Applications of time-resolved resonance Raman spectroscopy to the study of short-lived free radicals produced by ionizing radiation are briefly reviewed. Potential advantages and limitations of this technique are discussed in the light of given examples. The reduction of p-nitrobenzylchloride and......Applications of time-resolved resonance Raman spectroscopy to the study of short-lived free radicals produced by ionizing radiation are briefly reviewed. Potential advantages and limitations of this technique are discussed in the light of given examples. The reduction of p......-nitrobenzylchloride and subsequent formation of the p-nitrobenzyl radical and the reaction of p-nitrotoluene with O– are studied by resonance Raman and optical absorption spectroscopy....

  6. Viscous-shock-layer solutions for turbulent flow of radiating gas mixtures in chemical equilibrium

    Science.gov (United States)

    Anderson, E. C.; Moss, J. N.

    1975-01-01

    The viscous-shock-layer equations for hypersonic laminar and turbulent flows of radiating or nonradiating gas mixtures in chemical equilibrium are presented for two-dimensional and axially-symmetric flow fields. Solutions were obtained using an implicit finite-difference scheme and results are presented for hypersonic flow over spherically-blunted cone configurations at freestream conditions representative of entry into the atmosphere of Venus. These data are compared with solutions obtained using other methods of analysis.

  7. Viscous shock layer solutions for turbulent flow of radiating gas mixtures in chemical equilibrium

    Science.gov (United States)

    Anderson, E. C.; Moss, J. N.

    1975-01-01

    The viscous shock layer equations for hypersonic laminar and turbulent flows of radiating or nonradiating gas mixtures in chemical equilibrium are presented for two-dimensional and axially symmetric flow fields. Solutions are obtained using an implicit finite difference scheme and results are presented for hypersonic flow over spherically blunted cone configurations at free stream conditions representative of entry into the atmosphere of Venus. These data are compared with solutions obtained using other methods of analysis.

  8. Prediction of shock-layer ultraviolet radiation for hypersonic vehicles in near space

    Directory of Open Access Journals (Sweden)

    Niu Qinglin

    2016-10-01

    Full Text Available A systemic and validated model was developed to predict ultraviolet spectra features from the shock layer of near-space hypersonic vehicles in the “solar blind” band region. Computational procedures were performed with 7-species thermal non-equilibrium fluid mechanics, finite rate chemistry, and radiation calculations. The thermal non-equilibrium flow field was calculated with a two-temperature model by the finite volume technique and verified against the bow-shock ultra-violet (BSUV flight experiments. The absorption coefficient of the mixture gases was evaluated with a line-by-line method and validated through laboratory shock tube measurements. Using the line of sight (LOS method, radiation was calculated from three BSUV flights at altitudes of 38, 53.5 and 71 km. The investigation focused on the level and structure of ultraviolet spectra radiated from a NO band system in wavelengths of 200–400 nm. Results predicted by the current model show qualitative spatial agreement with the measured data. At a velocity of 3.5 km/s (about Mach 11, the peak absolute intensity at an altitude of 38 km is two orders of magnitude higher than that at 53.5 km. Under the same flight conditions, the spectra structures have quite a similar distribution at different viewing angles. The present computational model performs well in the prediction of the ultraviolet spectra emitted from the shock layer and will contribute to the investigation and analysis of radiative features of hypersonic vehicles in near space.

  9. Research with stored ions produced using synchrotron radiation

    International Nuclear Information System (INIS)

    Church, D.A.; Kravis, S.D.; Meron, M.; Johnson, B.M.; Jones, K.W.; Sellin, I.A.; O, C.S.; Levin, J.C.; Short, R.T.

    1987-01-01

    A distribution of argon ion charge states has been produced by inner shell photoionization of argon atoms using x-ray synchrotron radiation. These ions were stored in a Penning ion trap at moderate to very low well depths, and analog-detected yielding narrow charge-to-mass spectrum linewidths. Estimates of ion densities indicated that ion-ion collisional energy transfer should be rapid, leading to thermalization. Measurements using variants of this novel stored, multi-charged ion gas are considered

  10. A physics informed emulator for laser-driven radiating shock simulations

    KAUST Repository

    McClarren, Ryan G.; Ryu, D.; Paul Drake, R.; Grosskopf, Michael; Bingham, Derek; Chou, Chuan-Chih; Fryxell, Bruce; van der Holst, Bart; Paul Holloway, James; Kuranz, Carolyn C.; Mallick, Bani; Rutter, Erica; Torralva, Ben R.

    2011-01-01

    This work discusses the uncertainty quantification aspect of quantification of margin and uncertainty (QMU) in the context of two linked computer codes. Specifically, we present a physics based reduction technique to deal with functional data from the first code and then develop an emulator for this reduced data. Our particular application deals with conditions created by laser deposition in a radiating shock experiment modeled using the Lagrangian, radiation-hydrodynamics code Hyades. Our goal is to construct an emulator and perform a sensitivity analysis of the functional output from Hyades to be used as an initial condition for a three-dimensional code that will compute the evolution of the radiating shock at later times. Initial attempts at purely statistical data reduction techniques, were not successful at reducing the number of parameters required to describe the Hyades output. We decided on an alternate approach using physical arguments to decide what features/locations of the output were relevant (e.g., the location of the shock front or the location of the maximum pressure) and then used a piecewise linear fit between these locations. This reduced the number of outputs needed from the emulator to 40, down from the O(1000) points in the Hyades output. Then, using Bayesian MARS and Gaussian process regression, we were able to build emulators for Hyades and study sensitivities to input parameters. © 2011 Elsevier Ltd. All rights reserved.

  11. A physics informed emulator for laser-driven radiating shock simulations

    KAUST Repository

    McClarren, Ryan G.

    2011-09-01

    This work discusses the uncertainty quantification aspect of quantification of margin and uncertainty (QMU) in the context of two linked computer codes. Specifically, we present a physics based reduction technique to deal with functional data from the first code and then develop an emulator for this reduced data. Our particular application deals with conditions created by laser deposition in a radiating shock experiment modeled using the Lagrangian, radiation-hydrodynamics code Hyades. Our goal is to construct an emulator and perform a sensitivity analysis of the functional output from Hyades to be used as an initial condition for a three-dimensional code that will compute the evolution of the radiating shock at later times. Initial attempts at purely statistical data reduction techniques, were not successful at reducing the number of parameters required to describe the Hyades output. We decided on an alternate approach using physical arguments to decide what features/locations of the output were relevant (e.g., the location of the shock front or the location of the maximum pressure) and then used a piecewise linear fit between these locations. This reduced the number of outputs needed from the emulator to 40, down from the O(1000) points in the Hyades output. Then, using Bayesian MARS and Gaussian process regression, we were able to build emulators for Hyades and study sensitivities to input parameters. © 2011 Elsevier Ltd. All rights reserved.

  12. Shape of shock wave produced by a concentrated impact on a surface

    International Nuclear Information System (INIS)

    Nutt, G.; Klein, L.

    1981-01-01

    An approximate similarity solution, derived by Raizer, of a concentrated impact (or intense explosion) at the boundary of a semi-infinite volume of a perfect gas is used to determine the propagation velocity of the shock front as a function of its position. This velocity function is then used to obtain the shape of the propagating shock wave. It is shown that dish-shaped shock fronts are formed when the movement of the gas at the surface is into the gas region and that cup-shaped shock fronts are formed when the movement is out of the gas region. Comparison of these results with the shapes of explosions and meteorite craters are discussed

  13. Relativistic Electrons Produced by Foreshock Disturbances Observed Upstream of Earth's Bow Shock

    Science.gov (United States)

    Wilson, L. B., III; Sibeck, D. G.; Turner, D. L.; Osmane, A.; Caprioli, D.; Angelopoulos, V.

    2016-01-01

    Charged particles can be reflected and accelerated by strong (i.e., high Mach number) astrophysical collisionless shock waves, streaming away to form a foreshock region in communication with the shock. Foreshocks are primarily populated by suprathermal ions that can generate foreshock disturbances-largescale (i.e., tens to thousands of thermal ion Larmor radii), transient (approximately 5-10 per day) structures. They have recently been found to accelerate ions to energies of several keV. Although electrons in Saturn's high Mach number (M > 40) bow shock can be accelerated to relativistic energies (nearly 1000 keV), it has hitherto been thought impossible to accelerate electrons beyond a few tens of keV at Earth's low Mach number (1 =M foreshock disturbances to energies up to at least approximately 300 keV. Although such energetic electrons have been previously observed, their presence has been attributed to escaping magnetospheric particles or solar events. These relativistic electrons are not associated with any solar or magnetospheric activity. Further, due to their relatively small Larmor radii (compared to magnetic gradient scale lengths) and large thermal speeds (compared to shock speeds), no known shock acceleration mechanism can energize thermal electrons up to relativistic energies. The discovery of relativistic electrons associated with foreshock structures commonly generated in astrophysical shocks could provide a new paradigm for electron injections and acceleration in collisionless plasmas.

  14. Viscous-shock-layer solutions with coupled radiation and ablation injection for earth entry

    Science.gov (United States)

    Gupta, Roop N.; Lee, Kam-Pui; Moos, James N.; Sutton, Kenneth

    1990-01-01

    Results are obtained for the forebody of a planetary exploration vehicle entering the earth's atmosphere. A viscous-shock-layer analysis is used assuming the flow to be laminar and in chemical equilibrium. Presented results include coupled radiation and ablation injection. This study further includes the effect of different transport and thermodynamic properties and radiation models. A Lewis number of 1.4 appears adequate for the radiation-dominated flows. Five velocities corresponding to different possible trajectory points at an altitude of 70 km have been further analyzed in detail. Sublimation and radiative equilibrium wall temperatures are employed for cases with and without coupled injection, respectively. For the cases analyzed here, the mass injection rates are small. However, the rates could become large if a lower altitude is used for aerobraking and/or the body size is increased. A comparison of the equilibrium results with finite-rate chemistry calculation shows the flowfield to be in chemical equilibrium.

  15. Synchrotron self-inverse Compton radiation from reverse shock on GRB 120326A

    Energy Technology Data Exchange (ETDEWEB)

    Urata, Yuji [Institute of Astronomy, National Central University, Chung-Li 32054, Taiwan (China); Huang, Kuiyun; Takahashi, Satoko [Academia Sinica Institute of Astronomy and Astrophysics, Taipei 106, Taiwan (China); Im, Myungshin; Kim, Jae-Woo; Jang, Minsung [Center for the Exploration of the Origin of the Universe, Department of Physics and Astronomy, FPRD, Seoul National University, Shillim-dong, San 56-1, Kwanak-gu, Seoul (Korea, Republic of); Yamaoka, Kazutaka [Solar-Terrestrial Environment Laboratory, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601 (Japan); Tashiro, Makoto [Department of Physics, Saitama University, Shimo-Okubo, Saitama 338-8570 (Japan); Pak, Soojong, E-mail: urata@astro.ncu.edu.tw [School of Space Research, Kyung Hee University, Yongin, Gyeonggi 446-701 (Korea, Republic of)

    2014-07-10

    We present multi-wavelength observations of a typical long duration GRB 120326A at z = 1.798, including rapid observations using a Submillimeter Array (SMA) and a comprehensive monitoring in the X-ray and optical. The SMA observation provided the fastest detection to date among seven submillimeter afterglows at 230 GHz. The prompt spectral analysis, using Swift and Suzaku, yielded a spectral peak energy of E{sub peak}{sup src}=107.8{sub −15.3}{sup +15.3} keV and an equivalent isotropic energy of E{sub iso} as 3.18{sub −0.32}{sup +0.40}×10{sup 52} erg. The temporal evolution and spectral properties in the optical were consistent with the standard forward shock synchrotron with jet collimation (6.°69 ± 0.°16). The forward shock modeling, using a two-dimensional relativistic hydrodynamic jet simulation, was also determined by the reasonable burst explosion and the synchrotron radiation parameters for the optical afterglow. The X-ray light curve showed no apparent jet break and the temporal decay index relation between the X-ray and optical (αo – α{sub X} = –1.45 ± 0.10) indicated different radiation processes in each of them. Introducing synchrotron self-inverse Compton radiation from reverse shock is a possible solution, and the detection and slow decay of the afterglow in submillimeter supports that this is a plausible idea. The observed temporal evolution and spectral properties, as well as forward shock modeling parameters, enabled us to determine reasonable functions to describe the afterglow properties. Because half of the events share similar properties in the X-ray and optical as the current event, GRB 120326A will be a benchmark with further rapid follow-ups, using submillimeter instruments such as an SMA and the Atacama Large Millimeter/submillimeter Array.

  16. Synchrotron self-inverse Compton radiation from reverse shock on GRB 120326A

    International Nuclear Information System (INIS)

    Urata, Yuji; Huang, Kuiyun; Takahashi, Satoko; Im, Myungshin; Kim, Jae-Woo; Jang, Minsung; Yamaoka, Kazutaka; Tashiro, Makoto; Pak, Soojong

    2014-01-01

    We present multi-wavelength observations of a typical long duration GRB 120326A at z = 1.798, including rapid observations using a Submillimeter Array (SMA) and a comprehensive monitoring in the X-ray and optical. The SMA observation provided the fastest detection to date among seven submillimeter afterglows at 230 GHz. The prompt spectral analysis, using Swift and Suzaku, yielded a spectral peak energy of E peak src =107.8 −15.3 +15.3 keV and an equivalent isotropic energy of E iso as 3.18 −0.32 +0.40 ×10 52 erg. The temporal evolution and spectral properties in the optical were consistent with the standard forward shock synchrotron with jet collimation (6.°69 ± 0.°16). The forward shock modeling, using a two-dimensional relativistic hydrodynamic jet simulation, was also determined by the reasonable burst explosion and the synchrotron radiation parameters for the optical afterglow. The X-ray light curve showed no apparent jet break and the temporal decay index relation between the X-ray and optical (αo – α X = –1.45 ± 0.10) indicated different radiation processes in each of them. Introducing synchrotron self-inverse Compton radiation from reverse shock is a possible solution, and the detection and slow decay of the afterglow in submillimeter supports that this is a plausible idea. The observed temporal evolution and spectral properties, as well as forward shock modeling parameters, enabled us to determine reasonable functions to describe the afterglow properties. Because half of the events share similar properties in the X-ray and optical as the current event, GRB 120326A will be a benchmark with further rapid follow-ups, using submillimeter instruments such as an SMA and the Atacama Large Millimeter/submillimeter Array.

  17. The spectrum of mutation produced by low dose radiation

    International Nuclear Information System (INIS)

    Morley, Alexander A.; Turner, David R.

    2004-01-01

    Inherited mutations are the basis of evolution and acquired mutations in humans are important in ageing, cancer and possibly various forms of tissue degeneration. Mutations are responsible for many of the long-term effects of radiation. However, sensitive direct detection of mutations in humans has been difficult. The aims of the project were to develop methods for the sensitive enumeration of mutations in DNA, to measure mutation frequencies in a wide variety of tissue types and to quantify the mutational effect of direct oxidative damage produced by radiation, at both high and low doses. The project was successful in developing a sensitive method which could detect mutations directly in the genetic material, DNA at a sensitivity of 1 mutated molecule in 1000000000 unmutated molecules. However a number of methodological problems had to be overcome and lack of ongoing funding made it impossible to fulfill all of the aims of the project

  18. Effects and radiation dose to patients during extracorporeal shock wave lithotripsy for kidney stones

    International Nuclear Information System (INIS)

    Weng Zhigen; Shao Songsheng; Shao Min

    1991-01-01

    Extracorporeal shock wave lithotripsy (ESWL) is rapidly becoming an accepted treatment of renal calculi. Since fluoroscopy is involved in it to image the stones, it is important to know how much radiation and effects the patients receive during ESWL. Surface radiation exposure to 134 patients and medical personnel were measured during the course of ESWL using LiF(Mg, P, Cu) thermoluminescent dosimeters. Initial results showed an average skin exposure of 162 mSv per case, with a wide range of 5 to 2360 mSv. Factors influencing exposure levels include stone characteristics (location, size and opacity), physician's experience and number of shocks required. The monthly radiation dose to personnel working in the ESWL suite averaged 0.07-0.54 mSv. The effects of radiation to patients were observed pre-and post-ESWL by using white blood cell counts, lyphocyte micronucleus assays and chromosome aberration analysis. White blood cell counts rose or reduced to > 1000 cells in 50 per cent of cases and rose in one third of cases. Lymphocyte micronuclei and chromosome aberrations were observed in 20 patients during the cources. The average frequency of micronuclei was 0.5 per mille pre-ESWL and 1 per mille post-ESWL (P < 0.05). The dicentric chromosomes were markedly increased as compared with those of pre-ESWL with statistically significant difference (P < 0.05)

  19. Toxic shock syndrome

    Science.gov (United States)

    Staphylococcal toxic shock syndrome; Toxic shock-like syndrome; TSLS ... Toxic shock syndrome is caused by a toxin produced by some types of staphylococcus bacteria. A similar problem, called toxic shock- ...

  20. A numerical study of the stability of radiative shocks. [in accretion flows onto white dwarf stars

    Science.gov (United States)

    Imamura, J. N.; Wolff, M. T.; Durisen, R. H.

    1984-01-01

    Attention is given to the oscillatory instability of optically thin radiative shocks in time-dependent numerical calculations of accretion flows onto degenerate dwarfs. The present nonlinear calculations yield good quantitative agreement with the linear results obtained for oscillation frequencies, damping rates, and critical alpha-values. The fundamental mode and the first overtone in the shock radius and luminosity variations can be clearly identified, and evidence is sometimes seen for the second overtone. Time-dependent calculations are also performed which include additional physics relevant to degenerate dwarf accretion, such as electron thermal conduction, unequal electron and ion temperatures, Compton cooling, and relativistic corrections to the bremsstrahlung cooling law. All oscillatory modes are found to be damped, and hence stable, in the case of a 1-solar mass white dwarf accreting in spherical symmetry.

  1. Luminosity profiles and the evolution of shock waves in general relativistic radiating spheres

    International Nuclear Information System (INIS)

    Herrera, L.; Nunez, L.A.

    1989-10-01

    A method recently proposed by the authors to study the evolution of discontinuities in radiating spherically symmetric distributions of matter is systematically applied to model the evolution of a composite radiant sphere. The matter configuration, free of singularities, is divided in two regions by a shock wave front, and at each side of this interface a different equation of state is considered. Solutions are matched across the shock via the Rankine-Hugoniot conditions while the outer region metric joins the Vaidya solution at the boundary surface. The influence on the evolution of these composite spheres of different shapes of neutrino outburst profiles, and particular neutrino-transfer processes from the inner core to the outer mantel is explored. Prospective applications to supernova scenarios are discussed. (author). 18 refs, 4 figs, 1 tab

  2. Radiation degradation of biological residues (Aflatoxins) produced in food laboratory

    International Nuclear Information System (INIS)

    Rogovschi, Vladimir D.; Aquino, Simone; Nunes, Thaise C.F.; Trindade, Reginaldo A.; Villavicencio, Anna L.C.H.; Zorzete, Patricia; Correa, Benedito

    2007-01-01

    Some molds have the capacity to produce substances that are toxic and generally cancer-causing agents, such as aflatoxins, that stand between the most important carcinogenic substances (class one of the agents which are certainly carcinogenous for human people according to the International Agency for Research on Cancer). Aspergillus spp. is present in world-wide distribution, with predominance in tropical and subtropical regions growing in any substratum. The aim of this work is establish a minimum dose of radiation that degrades aflatoxins produced by fungi Aspergillus spp. The Aspergillus spp. colonies will be cultivated in coconut agar medium and the samples will be conditioned in appropriate bags for irradiation treatment of contaminated material and processed in the Gammacell 220 with dose of 20 kGy. (author)

  3. Radiation degradation of biological residues (Aflatoxins) produced in food laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Rogovschi, Vladimir D.; Aquino, Simone; Nunes, Thaise C.F.; Trindade, Reginaldo A.; Villavicencio, Anna L.C.H. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (brazil)]. E-mails: vladrogo@yahoo.com.br; villavic@ipen.br; Zorzete, Patricia; Correa, Benedito [Universidade de Sao Paulo, SP (Brazil). Inst. de Ciencias Biomedicas]. E-mail: correabe@usp.br

    2007-07-01

    Some molds have the capacity to produce substances that are toxic and generally cancer-causing agents, such as aflatoxins, that stand between the most important carcinogenic substances (class one of the agents which are certainly carcinogenous for human people according to the International Agency for Research on Cancer). Aspergillus spp. is present in world-wide distribution, with predominance in tropical and subtropical regions growing in any substratum. The aim of this work is establish a minimum dose of radiation that degrades aflatoxins produced by fungi Aspergillus spp. The Aspergillus spp. colonies will be cultivated in coconut agar medium and the samples will be conditioned in appropriate bags for irradiation treatment of contaminated material and processed in the Gammacell 220 with dose of 20 kGy. (author)

  4. A physics informed emulator for laser-driven radiating shock simulations

    International Nuclear Information System (INIS)

    McClarren, Ryan G.; Ryu, D.; Paul Drake, R.; Grosskopf, Michael; Bingham, Derek; Chou, Chuan-Chih; Fryxell, Bruce; Holst, Bart van der; Paul Holloway, James; Kuranz, Carolyn C.; Mallick, Bani; Rutter, Erica; Torralva, Ben R.

    2011-01-01

    This work discusses the uncertainty quantification aspect of quantification of margin and uncertainty (QMU) in the context of two linked computer codes. Specifically, we present a physics based reduction technique to deal with functional data from the first code and then develop an emulator for this reduced data. Our particular application deals with conditions created by laser deposition in a radiating shock experiment modeled using the Lagrangian, radiation-hydrodynamics code Hyades. Our goal is to construct an emulator and perform a sensitivity analysis of the functional output from Hyades to be used as an initial condition for a three-dimensional code that will compute the evolution of the radiating shock at later times. Initial attempts at purely statistical data reduction techniques, were not successful at reducing the number of parameters required to describe the Hyades output. We decided on an alternate approach using physical arguments to decide what features/locations of the output were relevant (e.g., the location of the shock front or the location of the maximum pressure) and then used a piecewise linear fit between these locations. This reduced the number of outputs needed from the emulator to 40, down from the O(1000) points in the Hyades output. Then, using Bayesian MARS and Gaussian process regression, we were able to build emulators for Hyades and study sensitivities to input parameters. - Highlights: → Uncertainty quantification for two linked computer codes is investigated. → We perform physics-based dimension reduction on the code output. → This reduces the uncertain degrees of freedom from hundreds to tens.

  5. Causal dissipation and shock profiles in the relativistic fluid dynamics of pure radiation.

    Science.gov (United States)

    Freistühler, Heinrich; Temple, Blake

    2014-06-08

    CURRENT THEORIES OF DISSIPATION IN THE RELATIVISTIC REGIME SUFFER FROM ONE OF TWO DEFICITS: either their dissipation is not causal or no profiles for strong shock waves exist. This paper proposes a relativistic Navier-Stokes-Fourier-type viscosity and heat conduction tensor such that the resulting second-order system of partial differential equations for the fluid dynamics of pure radiation is symmetric hyperbolic. This system has causal dissipation as well as the property that all shock waves of arbitrary strength have smooth profiles. Entropy production is positive both on gradients near those of solutions to the dissipation-free equations and on gradients of shock profiles. This shows that the new dissipation stress tensor complies to leading order with the principles of thermodynamics. Whether higher order modifications of the ansatz are required to obtain full compatibility with the second law far from the zero-dissipation equilibrium is left to further investigations. The system has exactly three a priori free parameters χ , η , ζ , corresponding physically to heat conductivity, shear viscosity and bulk viscosity. If the bulk viscosity is zero (as is stated in the literature) and the total stress-energy tensor is trace free, the entire viscosity and heat conduction tensor is determined to within a constant factor.

  6. Turbulent amplification of magnetic fields in laboratory laser-produced shock waves

    International Nuclear Information System (INIS)

    Meinecke, J.; Doyle, H.W.; Bell, A.R.; Schekochihin, A.A.; Miniati, F.; Bingham, R.; Koenig, M.; Pelka, A.; Ravasio, A.; Yurchak, R.

    2014-01-01

    X-ray and radio observations of the supernova remnant Cassiopeia A reveal the presence of magnetic fields about 100 times stronger than those in the surrounding interstellar medium. Field coincident with the outer shock probably arises through a nonlinear feedback process involving cosmic rays. The origin of the large magnetic field in the interior of the remnant is less clear but it is presumably stretched and amplified by turbulent motions. Turbulence may be generated by hydrodynamic instability at the contact discontinuity between the supernova ejecta and the circumstellar gas. However, optical observations of Cassiopeia A indicate that the ejecta are interacting with a highly inhomogeneous, dense circumstellar cloud bank formed before the supernova explosion. Here we investigate the possibility that turbulent amplification is induced when the outer shock overtakes dense clumps in the ambient medium. We report laboratory experiments that indicate the magnetic field is amplified when the shock interacts with a plastic grid. We show that our experimental results can explain the observed synchrotron emission in the interior of the remnant. The experiment also provides a laboratory example of magnetic field amplification by turbulence in plasmas, a physical process thought to occur in many astrophysical phenomena. (authors)

  7. Comparison of theory with atomic oxygen 130.4 nm radiation data from the Bow Shock ultraviolet 2 rocket flight

    Science.gov (United States)

    Levin, Deborah A.; Candler, Graham V.; Collins, Robert J.; Howlett, Carl L.; Espy, Patrick; Whiting, Ellis; Park, Chul

    1993-01-01

    Comparison is made between the results obtained from a state-of-the-art flow and radiative model and bow shock vacuum ultraviolet (VUV) data obtained the recent Bow Shock 2 Flight Experiment. An extensive data set was obtained from onboard rocket measurements at a reentry speed of 5 km/sec between the altitudes of approximately 65-85 km. A description of the NO photoionization cell used, the data, and the interpretation of the data will be presented. The primary purpose of the analyses is to assess the utility of the data and to propose a radiation model appropriate to the flight conditions of Bow Shock 2. Theoretical predictions based on flow modeling discussed in earlier work and a new radiation model are compared with data.

  8. Heat-shock induction of ionizing radiation resistance in Saccharomyces cerevisiae, and the correlation with stationary growth phase

    International Nuclear Information System (INIS)

    Mitchel, R.E.J.; Morrison, D.P.

    1982-01-01

    Radiation resistance and thermal resistance vary as a function of culture temperature in logarithmically growing Saccharomyces cerevisiae and are related to the optimum temperature for growth. Radiation resistance and thermal resistance were also induced when cells grown at low temperatures were subjected to a heat shock at or above the optimum growth temperature. Exposure to ionizing radiation followed by a short incubation at low temperature also induced resistance to killing by heat. Heat-shocked cells are induced to a level of thermal and radioresistance much greater than the characteristic resistance level of cells grown continuously at the shock temperature. This high level of resistance, which resembles that of stationary-phase cells, decays to the characteristic log-phase level within one doubling of cell number after the heat shock. Both induction of resistance and decay of that induction require protein synthesis. It is postulated that induction of resistance by heat shock or ionizing radiation is a response of the cells to stress and represents a preparation to enter stationary phase

  9. Collisionless shock waves

    International Nuclear Information System (INIS)

    Sagdeev, R.Z.; Kennel, C.F.

    1991-01-01

    Collisionless shocks cannot occur naturally on the earth, because nearly all matter here consists of electrically neutral atoms and molecules. In space, however, high temperatures and ultraviolet radiation from hot stars decompose atoms into their constituent nuclei and electrons, producing a soup of electrically charged particles known as a plasma. Plasma physicists proposed that the collective electrical and magnetic properties of plasmas could produce interactions that take the place of collisions and permit shocks to form. In 1964 the theoretical work found its first experimental confirmation. Norman F. Ness and his colleagues at the Goddard Space Flight Center, using data collected from the iMP-1 spacecraft, detected clear signs that a collisionless shock exists where the solar wind encounters the earth's magnetic field. More recent research has demonstrated that collisionless shocks appear in a dazzling array of astronomical settings. For example, shocks have been found in the solar wind upstream (sunward) of all the planet and comets that have been visited by spacecraft. Violent flares on the sun generate shocks that propagate to the far reaches of the solar system; tremendous galactic outbursts create disruptions in the intergalactic medium that are trillions of times larger. In addition, many astrophysicists think that shocks from supernova explosions in our galaxy accelerate cosmic rays, a class of extraordinarily energetic elementary particles and atomic nuclei that rain down on the earth from all directions

  10. Radiation degradation of biological waste (aflatoxins) produced in food laboratory

    International Nuclear Information System (INIS)

    Rogovschi, Vladimir Dias

    2009-01-01

    Many filamentous fungi can produce secondary metabolites, called mycotoxins, which can be found in food and agricultural products. One of the main genera of myco toxigenic fungi related to the food chain is the Aspergillus spp. There are over 400 mycotoxins described in the literature, the most common the aflatoxins B1, B2, G1 and G2. The mycotoxins are commonly found in foods and are considered one of the most dangerous contaminants. The aflatoxin B1 is classified in group one by the International Agency of Research on Cancer. Aflatoxins resisting for more than one hour in autoclave making it necessary to other means of degradation of these toxins. This work aimed to observe the effects of gamma radiation of 60 Co and electron beams in the degradation of aflatoxins and compare the damage caused on the morphology of the Aspergillus flavus. The fungus was grown on potato dextrose agar (PDA) for 10 days and was subsequently transferred to coconut agar medium, and maintained for 14 days at 25 degree C. After this step the coconut agar was ground to become a homogeneous pasty and was irradiated with doses of 2.5, 5.0, 10 and 20 kGy. The samples used in scanning electron microscopy were irradiated with doses of 0, 2.5, 5.0, 10 and 20 kGy with sources of 60 Co and electron beams. Irradiation with electron accelerator showed a slightly higher degradation to gamma radiation, reducing 29.93 %, 34.50 %, 52.63 % and 72.30 % for doses of 2.5, 5.0, 10 and 20 kGy, respectively. The Scanning Electron Microscopy showed that doses of 2.5 to 10 kGy did not cause damage to the fungus, but with a dose of 20 kGy it can be observed fungal damage to structures. (author)

  11. Development and Transition of the Radiation, Interplanetary Shocks, and Coronal Sources (RISCS) Toolset

    Science.gov (United States)

    Spann, James F.; Zank, G.

    2014-01-01

    We outline a plan to develop and transition a physics based predictive toolset called The Radiation, Interplanetary Shocks, and Coronal Sources (RISCS) to describe the interplanetary energetic particle and radiation environment throughout the inner heliosphere, including at the Earth. To forecast and "nowcast" the radiation environment requires the fusing of three components: 1) the ability to provide probabilities for incipient solar activity; 2) the use of these probabilities and daily coronal and solar wind observations to model the 3D spatial and temporal heliosphere, including magnetic field structure and transients, within 10 Astronomical Units; and 3) the ability to model the acceleration and transport of energetic particles based on current and anticipated coronal and heliospheric conditions. We describe how to address 1) - 3) based on our existing, well developed, and validated codes and models. The goal of RISCS toolset is to provide an operational forecast and "nowcast" capability that will a) predict solar energetic particle (SEP) intensities; b) spectra for protons and heavy ions; c) predict maximum energies and their duration; d) SEP composition; e) cosmic ray intensities, and f) plasma parameters, including shock arrival times, strength and obliquity at any given heliospheric location and time. The toolset would have a 72 hour predicative capability, with associated probabilistic bounds, that would be updated hourly thereafter to improve the predicted event(s) and reduce the associated probability bounds. The RISCS toolset would be highly adaptable and portable, capable of running on a variety of platforms to accommodate various operational needs and requirements. The described transition plan is based on a well established approach developed in the Earth Science discipline that ensures that the customer has a tool that meets their needs

  12. Collision of two shock waves as a hypothetical mechanism of producing drifting radio bursts in the 400-500 MHz range

    International Nuclear Information System (INIS)

    Karlicky, M.

    1978-01-01

    After the proton flare of July 3, 1974 a hitherto unclassified phenomenon with a diffusion ''banner'' and with a considerably decelerating drift within the type II and III burst drifts range was observed in the radio dynamic spectrum between 410 and 470 MHz. The hypothesis is presented that the phenomenon is due to the collision of two shock waves, propagating against one another, during which the flux of electromagnetic radiation is considerably enhanced relative to the sum of the fluxes of the electromagnetic radiation of the individual shock waves. The Newkirk 4-density model of the corona is used to describe the phenomenon, the mechanism of plasmon-plasmon conversion in electromagnetic radiation with a double plasma frequency is considered and, according to the parameters derived from the dynamic spectrum, the velocities, radii of curvature and direction of propagation of the anticipated shock waves are analysed in a simplifed symmetric case. (author)

  13. THE NuSTAR X-RAY SPECTRUM OF HERCULES X-1: A RADIATION-DOMINATED RADIATIVE SHOCK

    Energy Technology Data Exchange (ETDEWEB)

    Wolff, Michael T.; Wood, Kent S. [Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States); Becker, Peter A. [Department of Physics and Astronomy, George Mason University, Fairfax, VA 22030-4444 (United States); Gottlieb, Amy M.; Marcu-Cheatham, Diana M.; Pottschmidt, Katja [Department of Physics and Center for Space Science and Technology, University of Maryland Baltimore County, Baltimore, MD 21250 (United States); Fürst, Felix [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Hemphill, Paul B. [Center for Astrophysics and Space Sciences, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0424 (United States); Schwarm, Fritz-Walter; Wilms, Jörn [Dr. Karl-Remeis-Sternwarte and ECAP, Sternwartstr, 7, D-96049 Bamberg (Germany)

    2016-11-10

    We report on new spectral modeling of the accreting X-ray pulsar Hercules X-1. Our radiation-dominated radiative shock model is an implementation of the analytic work of Becker and Wolff on Comptonized accretion flows onto magnetic neutron stars. We obtain a good fit to the spin-phase-averaged 4–78 keV X-ray spectrum observed by the Nuclear Spectroscopic Telescope Array during a main-on phase of the Her X-1 35 day accretion disk precession period. This model allows us to estimate the accretion rate, the Comptonizing temperature of the radiating plasma, the radius of the magnetic polar cap, and the average scattering opacity parameters in the accretion column. This is in contrast to previous phenomenological models that characterized the shape of the X-ray spectrum, but could not determine the physical parameters of the accretion flow. We describe the spectral fitting details and discuss the interpretation of the accretion flow physical parameters.

  14. Transition and synchrotron radiation produced by electrons and particle discrimination

    International Nuclear Information System (INIS)

    Merkel, B.; Repellin, J.-P.; Sauvage, G.; Chollet, J.C.; Dialinas, M.; Gaillard, J.-M.; Hrisoho, A.; Jean, P.

    1976-01-01

    Transition radiation from a radiator of 650 lithium foils has been studied in a multiwire proportional chamber filled with a Xenon-CO 2 mixture for two experimental configurations. With the chamber immediately after the radiator, particle discrimination comparable to those reported in the litterature (90% efficiency for electrons, 10% for hadrons) have been observed. With magnetic bending between the radiator and the xenon chamber typical efficiencies of 87% for electrons and less than 0.4% for hadrons have been measured. The discrimination obtained is at least a factor 20 better than for the more conventional configuration. In the latter case, synchrotron radiation has also been observed

  15. Numerical procedure for the calculation of nonsteady spherical shock fronts with radiation

    International Nuclear Information System (INIS)

    Winkler, K.H.

    The basis of the numerical method is an implicit difference scheme with time backward differences to a freely moving coordinate system. The coordinate system itself is determined simultaneously with the iterative solution of the physical equations as a function of the physical variables. Shock fronts, even nonsteady ones, are calculated as discontinuities according to the Rankine--Hugoniot equations. The radiation field is obtained from the two-dimensional, static, spherically symmetric transport equation in conjunction with the time-dependent one-dimensional moment equations. No artificial viscosity of any type is ever used. The applicability of the method developed is demonstrated by an example involving the calculation of protostar collapse. 11 figures

  16. Narrow Radiative Recombination Continua: A Signature of Ions Crossing the Contact Discontinuity of Astrophysical Shocks

    Science.gov (United States)

    Behar, Ehud; Nordon, Raanan; Soker, Noam; Kastner, Joel H.; Yu, Young Sam

    2009-01-01

    X-rays from planetary nebulae (PNs) are believed to originate from a shock driven into the fast stellar wind (v 1000 kilometers per second) as it collides with an earlier circumstellar slow wind (v 10 kilometers per second). In theory, the shocked fast wind (hot hubble) and the ambient cold nebula can remain separated by magnetic fields along a surface referred to as the contact discontinuity (CD) that inhibits diffusion and heat conduction. The CD region is extremely difficult to probe directly owing to its small size and faint emission. This has largely left the study of CDs, stellar-shocks, and the associated micro-physics in the realm of theory. This paper presents spectroscopic evidence for ions from the hot bubble (kT approximately equal to 100 eV) crossing the CD and penetrating the cold nebular gas (kT approximately equal to 1 eV). Specifically, a narrow radiative recombination continuum (RRC) emission feature is identified in the high resolution X-ray spectrum of the PN BD+30degree3639 indicating bare C VII ions are recombining with cool electrons at kT(sub e) = 1.7 plus or minus 1.3 eV. An upper limit to the flux of the narrow RRC of H-like C VI is obtained as well. The RRCs are interpreted as due to C ions from the hot bubble of BD+30degree3639 crossing the CD into the cold nebula, where they ultimately recombine with its cool electrons. The RRC flux ratio of C VII to C VI constrains the temperature jump across the CD to deltakT greater than 80 eV, providing for the first time direct evidence for the stark temperature disparity between the two sides of an astrophysical CD, and constraining the role of magnetic fields and heat conduction accordingly. Two colliding-wind binaries are noted to have similar RRCs suggesting a temperature jump and CD crossing by ions may be common feature of stellar wind shocks.

  17. Data assimilation with an extended Kalman filter for impact-produced shock-wave dynamics

    International Nuclear Information System (INIS)

    Kao, Jim; Flicker, Dawn; Henninger, Rudy; Frey, Sarah; Ghil, Michael; Ide, Kayo

    2004-01-01

    Model assimilation of data strives to determine optimally the state of an evolving physical system from a limited number of observations. The present study represents the first attempt of applying the extended Kalman filter (EKF) method of data assimilation to shock-wave dynamics induced by a high-speed impact. EKF solves the full nonlinear state evolution and estimates its associated error-covariance matrix in time. The state variables obtained by the blending of past model evolution with currently available data, along with their associated minimized errors (or uncertainties), are then used as initial conditions for further prediction until the next time at which data becomes available. In this study, a one-dimensional (1D) finite-difference code is used along with data measured from a 1D flyer plate experiment. An ensemble simulation suggests that the nonlinearity of the modeled system can be reasonably tracked by EKF. The results demonstrate that the EKF assimilation of a limited amount of pressure data, measured at the middle of the target plate alone, helps track the evolution of all the state variables. The fidelity of EKF is further investigated with numerically generated synthetic data from so-called 'identical-twin experiments', in which the true state is known and various measurement techniques and strategies can be made easily simulated. We find that the EKF method can effectively assimilate the density fields, which are distributed sparsely in time to mimic radiographic data, into the modeled system

  18. Interferometric investigation of shock waves induced by a TEA-CO2 laser produced plasma in air in front of a solid target

    International Nuclear Information System (INIS)

    Apostol, D.; Apostol, I.; Cojocaru, E.; Draganescu, V.; Mihailescu, N.I.; Morjan, I.; Konov, I.V.

    1979-06-01

    The shock waves induced in the surrounding atmosphere by an air plasma were investigated by laser interferometry. The air breakdown plasma was produced by a TEA-CO 2 laser in front of a solid target. The results were compared to the predictions of theory of intense explosions in gases and a good agreement was inferred. It was also determined that the symmetry of the expansion of the initial shock wave is determined by the plasma source shape and, accordingly, depends on the laser power density incident on the target surface. However, for further stages all the shock waves expand spherically. (author)

  19. Radiation shielding phenolic fibers and method of producing same

    International Nuclear Information System (INIS)

    Ohtomo, K.

    1976-01-01

    A radiation shielding phenolic fiber is described comprising a filamentary phenolic polymer consisting predominantly of a sulfonic acid group-containing cured novolak resin and a metallic atom having a great radiation shielding capacity, the metallic atom being incorporated in the polymer by being chemically bound in the ionic state in the novolak resin. A method for the production of the fiber is discussed

  20. Measurement and Analysis of the Extreme Physical Shock Environment Experienced by Crane-Mounted Radiation Detection Systems.

    Energy Technology Data Exchange (ETDEWEB)

    Boyd, M [Texas A & M Univ., College Station, TX (United States); Erchinger, J [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Marianno, C [Texas A & M Univ., College Station, TX (United States); Kallenbach, Gene A. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Grypp, M [US Dept. of the Navy

    2017-09-01

    Potentially, radiation detectors at ports of entry could be mounted on container gantry crane spreaders to monitor cargo containers entering and leaving the country. These detectors would have to withstand the extreme physical environment experienced by these spreaders during normal operations. Physical shock data from the gable ends of a spreader were recorded during the loading and unloading of a cargo ship with two Lansmont SAVER 9X30 units (with padding) and two PCB Piezotronics model 340A50 accelerometers (hard mounted). Physical shocks in the form of rapid acceleration were observed in all accelerometer units with values ranging from 0.20 g’s to 199.99 g’s. The majority of the shocks for all the Lansmont and PCB accelerometers were below 50 g’s. The Lansmont recorded mean shocks of 21.83 ± 13.62 g’s and 24.78 ± 11.49 g’s while the PCB accelerometers experienced mean shocks of 34.39 ± 25.51 g’s and 41.77 ± 22.68 g’s for the landside and waterside units, respectively. Encased detector units with external padding should be designed to withstand at least 200 g’s of acceleration without padding and typical shocks of 30 g’s with padding for mounting on a spreader.

  1. Scintillation camera for establishing the coordinates of a radiation stimuli produced by a radiation field

    International Nuclear Information System (INIS)

    Zioni, J.; Klein, Y.; Inbar, D.

    1977-01-01

    A scintillation camera has a planar scintillating crystal that produces light events whose spatial distribution corresponds to the spatial distribution of the radiation stimuli causing such events, and a plurality of photomultipliers having photocathodes for receiving light from the crystal through a planar face thereof. Computing circuitry coupled to the photomultipliers computes the projection of a light event in the crystal on a reference axis by forming an analytical function of the outputs of the photomultipliers according to the spatial location of the light event in the crystal

  2. Assessment of the role of oxygen and mitochondria in heat shock induction of radiation and thermal resistance in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Mitchel, R.E.J.; Morrison, D.P.

    1983-01-01

    In response to a heat shock, the yeast Saccharomyces cerevisiae undergoes a large increase in its resistance to heat and, by the induction of its recombinational DNA repair capacity, a corresponding increase in resistance to radiation. Yeast which lack mitochondrial DNA, mitochondria-controlled protein synthetic apparatus, aerobic respiration, and electron transport (rho 0 strain) were used to assess the role of O 2 , mitochondria, and oxidative processes controlled by mitochondria in the induction of these resistances. We have found that rho 0 yeast grown and heat shocked in either the presence or absence of O 2 are capable of developing both radiation and heat resistance. We conclude that neither the stress signal nor its cellular consequences of induced heat and radiation resistance are directly dependent on O 2 , mitochondrial DNA, or mitochondria-controlled protein synthetic or oxidative processes

  3. Shock waves in luminous early-type stars

    International Nuclear Information System (INIS)

    Castor, J.I.

    1986-01-01

    Shock waves that occur in stellar atmospheres have their origin in some hydrodynamic instability of the atmosphere itself or of the stellar interior. In luminous early-type stars these two possibilities are represented by shocks due to an unstable radiatively-accelerated wind, and to shocks generated by the non-radial pulsations known to be present in many or most OB stars. This review is concerned with the structure and development of the shocks in these two cases, and especially with the mass loss that may be due specifically to the shocks. Pulsation-produced shocks are found to be very unfavorable for causing mass loss, owing to the great radiation efficiency that allows them to remain isothermal. The situation regarding radiatively-driven shocks remains unclear, awaiting detailed hydrodynamics calculations. 20 refs., 2 figs

  4. The effects of ionizing radiation on the performance of signaled and unsignalled bar-press shock postponement in the rat

    International Nuclear Information System (INIS)

    Burghardt, W.F. Jr.

    1988-01-01

    Forty-eight rats in four conditions were used to determine the efficacy of preshock warning tones in maintaining bar-press shock postponement performance after irradiation. The SIDMAN group performed without external cues. The SIGNAL group received a 5 sec warning tone preceding shock. The COSAV group had preshock warning tones available for 60 sec following a response on another lever, and was used to assess the ability to maintain performance on two levers simultaneously. In VISIG, warning tones always preceded shocks, but followed shock postponement responses unpredictably. Sham-irradiated control groups were used to compare baseline performance on each task, and for comparison with irradiated subjects. Irradiated subjects could perform the movements necessary to successfully avoid shock. They were able to detect and respond appropriately to preshock warning tones when present, although COSAV subjects did not continue to respond to produce them. Irradiated subjects experienced a significant and lasting increase in the number of shocks received, except when no external cues were available

  5. Laser readable thermoluminescent radiation dosimeters and methods for producing thereof

    International Nuclear Information System (INIS)

    Braunlich, P.F.; Tetzlaff, W.

    1989-01-01

    Thin layer thermoluminescent radiation dosimeters for use in laser readable dosimetry systems, and methods of fabricating such thin layer dosimeters are disclosed. The thin layer thermoluminescent radiation dosimeters include a thin substrate made from glass or other inorganic materials capable of withstanding high temperatures and high heating rates. A thin layer of a thermoluminescent phosphor material is heat bonded to the substrate using an inorganic binder such as glass. The dosimeters can be mounted in frames and cases for ease in handling. Methods of the invention include mixing a suitable phosphor composition and binder, both being in particulate or granular form. The mixture is then deposited onto a substrate such as by using mask printing techniques. The dosimeters are thereafter heated to fuse and bond the binder and phosphor to the substrate. 34 figs

  6. Does radiation exposure produce a protective effect among radiologists

    International Nuclear Information System (INIS)

    Matanoski, G.M.; Sternberg, A.; Elliott, E.A.

    1987-01-01

    The mortality experience of radiologists compared to that of other physician specialists demonstrates an increased risk of cancer deaths as well as deaths from all causes among physicians practicing in the early years of this century. However, for the radiologists who joined specialty societies after 1940, the age pattern of deaths has changed. Whereas among early entrants, young radiologists had higher mortality rates than those of other specialists; among later entrants, the young radiologists have lower mortality. However, as these later-entrant radiologists age, their rates appear to exceed those of other specialists. Although the level of radiation exposure is unknown, physicians in more recent years usually have lower cumulative doses. Lower radiation exposure may be one of a number of possible explanatory factors for the cross-over from protected to higher risk status as these physicians age

  7. Experimental study of the interaction of two laser-driven radiative shocks at the PALS laser

    Czech Academy of Sciences Publication Activity Database

    Singh, R.L.; Stehlé, C.; Suzuki-Vidal, F.; Kozlová, Michaela; Larour, J.; Chaulagain, Uddhab P.; Clayson, T.; Rodriguez, R.; Gil, J.M.; Nejdl, Jaroslav; Krůs, Miroslav; Dostál, Jan; Dudžák, Roman; Barroso, P.; Acef, O.; Cotelo, M.; Velarde, P.

    2017-01-01

    Roč. 23, June (2017), s. 20-30 ISSN 1574-1818 R&D Projects: GA MŠk EE2.3.30.0057; GA MŠk EE2.3.20.0279; GA MŠk ED1.1.00/02.0061; GA MŠk(CZ) LM2015083 EU Projects: European Commission(XE) 284464 - LASERLAB-EUROPE Grant - others:ELI Beamlines(XE) CZ.1.05/1.1.00/02.0061; OP VK 4 POSTDOK(XE) CZ.1.07/2.3.00/30.0057; LaserZdroj (OP VK 3)(XE) CZ.1.07/2.3.00/20.0279; ELI Beamlines(XE) CZ.1.05/1.1.00/02.0061 Institutional support: RVO:68378271 ; RVO:61389021 Keywords : radiative shocks * hydrodynamics laser-plasmas * spectroscopy * laboratory astrophysics Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 0.908, year: 2016

  8. Extracorporeal shock waves lithotripsy versus retrograde ureteroscopy: is radiation exposure a criterion when we choose which modern treatment to apply for ureteric stones?

    Directory of Open Access Journals (Sweden)

    Catalin Pricop

    2014-10-01

    Full Text Available The aim of this study is to compare two major urological procedures in terms of patient exposure to radiation. We evaluated 175 patients, that were subjected to retrograde ureteroscopy (URS and extracorporeal shock waves lithotripsy (ESWL for lumbar or pelvic ureteral lithiasis, at two urological departments. The C-arm Siemens (produced in 2010 by Siemens AG, Germany was used for ureteroscopy. The radiological devices of the lithotripters used in this study in the two clinical centers had similar characteristics. We evaluated patient exposure to ionizing radiation by using a relevant parameter, the air kerma-area product (PKA; all values in cGy cm2, calculated from the radiation dose values recorded by the fluoroscopy device. PKA depends on technical parameters that change due to anatomical characteristics of each case examined, such as body mass index (BMI, waist circumference, and stone location. For the patients subjected to ESWL for lumbar ureteral lithiasis the mean of PKA (cGy cm2 was 509 (SD=180, while for those treated for pelvic ureteral lithiasis the mean of PKA was 342 (SD=201. In the URS group for lumbar ureteral lithiasis, the mean of PKA (cGy cm2 was 892 (SD=436, while for patients with pelvic ureteral lithiasis, the mean of PKA was 601 (SD=429. The patients treated by URS had higher exposure to ionizing radiation dose than patients treated by ESWL. The risk factors of higher radiation doses were obesity, exposure time, and localization of the stones.

  9. On Shocks Driven by High-mass Planets in Radiatively Inefficient Disks. III. Observational Signatures in Thermal Emission and Scattered Light

    Science.gov (United States)

    Hord, Blake; Lyra, Wladimir; Flock, Mario; Turner, Neal J.; Mac Low, Mordecai-Mark

    2017-11-01

    Recent observations of the protoplanetary disk around the Herbig Be star HD 100546 show two bright features in infrared (H and {L}{\\prime } bands) at about 50 au,with one so far unexplained. We explore the observational signatures of a high-mass planet causing shock heating in order to determine if it could be the source of the unexplained infrared feature in HD 100546. More fundamentally, we identify and characterize planetary shocks as an extra, hitherto ignored, source of luminosity in transition disks. The RADMC-3D code is used to perform dust radiative transfer calculations on the hydrodynamical disk models, including volumetric heating. A stronger shock heating rate by a factor of 20 would be necessary to qualitatively reproduce the morphology of the second infrared source. Instead, we find that the outer edge of the gap carved by the planet heats up by about 50% relative to the initial reference temperature, which leads to an increase in the scale height. The bulge is illuminated by the central star, producing a lopsided feature in scattered light, as the outer gap edge shows an asymmetry in density and temperature attributable to a secondary spiral arm launched not from the Lindblad resonances but from the 2:1 resonance. We conclude that high-mass planets lead to shocks in disks that may be directly observed, particularly at wavelengths of 10 μm or longer, but that they are more likely to reveal their presence in scattered light by puffing up their outer gap edges and exciting multiple spiral arms.

  10. Polarization of photoelectrons produced from atoms by synchrotron radiation

    International Nuclear Information System (INIS)

    Hughes, V.W.; Lu, D.C.; Huang, K.N.

    1981-01-01

    The polarization of photoelectrons from stoms has proved to be an important tool for studying correlation effects in atoms, as well as relativistic effects such as the spin-orbit interaction. Extensive experimental and theoretical studies have been made of the Fano effect, which is the production of polarized electrons by photoionization of unpolarized atoms by circularly polarized light. The experiments have dealt mostly with alkali atoms and with photon energies slightly above the ionization thresholds. Measurements that could be made to utilize polarized radiation are discussed

  11. Energetic radiation produced during rocket-triggered lightning.

    Science.gov (United States)

    Dwyer, Joseph R; Uman, Martin A; Rassoul, Hamid K; Al-Dayeh, Maher; Caraway, Lee; Jerauld, Jason; Rakov, Vladimir A; Jordan, Douglas M; Rambo, Keith J; Corbin, Vincent; Wright, Brian

    2003-01-31

    Using a NaI(Tl) scintillation detector designed to operate in electrically noisy environments, we observed intense bursts of energetic radiation (> 10 kiloelectron volts) during the dart leader phase of rocket-triggered lightning, just before and possibly at the very start of 31 out of the 37 return strokes measured. The bursts had typical durations of less than 100 microseconds and deposited many tens of megaelectron volts into the detector. These results provide strong evidence that the production of runaway electrons is an important process during lightning.

  12. Infrared radiation emerging from smoke produced by brush fires

    Science.gov (United States)

    Weinman, J. A.; Olson, W. S.; Harshvardhan, M.

    1981-01-01

    The IR radiative transport properties of brush fire smoke clouds, computed for a model with finite horizontal dimensions as well as the more common plane-parallel model, are presented. The finite model is a three-dimensional version of the two-stream approximation applied to cubic clouds of steam, carbon, and silicates. Assumptions are made with regard to the shape and size distributions of the smoke particles. It is shown that 11.5-micron radiometry can detect fires beneath smoke clouds if the path integrated mass density of the smoke is less than or equal to 3 g/sq m.

  13. Chondrule destruction in nebular shocks

    Energy Technology Data Exchange (ETDEWEB)

    Jacquet, Emmanuel; Thompson, Christopher, E-mail: ejacquet@mnhn.fr [Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St George Street, Toronto, ON M5S 3H8 (Canada)

    2014-12-10

    Chondrules are millimeter-sized silicate spherules ubiquitous in primitive meteorites, but whose origin remains mysterious. One of the main proposed mechanisms for producing them is melting of solids in shock waves in the gaseous protoplanetary disk. However, evidence is mounting that chondrule-forming regions were enriched in solids well above solar abundances. Given the high velocities involved in shock models, destructive collisions would be expected between differently sized grains after passage of the shock front as a result of differential drag. We investigate the probability and outcome of collisions of particles behind a one-dimensional shock using analytic methods as well as a full integration of the coupled mass, momentum, energy, and radiation equations. Destruction of protochondrules seems unavoidable for solid/gas ratios ε ≳ 0.1, and possibly even for solar abundances because of 'sandblasting' by finer dust. A flow with ε ≳ 10 requires much smaller shock velocities (∼2 versus 8 km s{sup –1}) in order to achieve chondrule-melting temperatures, and radiation trapping allows slow cooling of the shocked fragments. Initial destruction would still be extensive; although re-assembly of millimeter-sized particles would naturally occur by grain sticking afterward, the compositional heterogeneity of chondrules may be difficult to reproduce. We finally note that solids passing through small-scale bow shocks around few kilometer-sized planetesimals might experience partial melting and yet escape fragmentation.

  14. A fractographic study of cracks produced by thermal shocks in 20MnMoNi55 and comparable weld material in water environment

    International Nuclear Information System (INIS)

    Toerroenen, K.; Rintamaa, R.; Kemppainen, M.

    1983-04-01

    This report gives the results of a fractographic study of cracks produced by thermal shocks in 20MnMoNi55 and comparable weld material in water environment. The basic crack growth mechanism is shown to be by mechanical fatigue, but after some crack growth indications of environmentally assisted cyclic crack growth is seen. (author)

  15. Ultrafast growth of wadsleyite in shock-produced melts and its implications for early solar system impact processes

    Energy Technology Data Exchange (ETDEWEB)

    Tschauner, Oliver; Asimow, Paul; Kostandova, Natalia; Ahrens, Thomas; Ma, Chi; Sinogeikin, Stanislav; Liu, Zhenxian; Fakra, Sirine; Tamura, Nobumichi

    2009-12-01

    We observed micrometer-sized grains of wadsleyite, a high-pressure phase of (Mg,Fe)2SiO4, in the recovery products of a shock experiment. We infer these grains crystallized from shock-generated melt over a time interval of <1 fs, the maximum time over which our experiment reached and sustained pressure sufficient to stabilize this phase. This rapid crystal growth rate (=1 m/s) suggests that, contrary to the conclusions of previous studies of the occurrence of high-pressure phases in shock-melt veins in strongly shocked meteorites, the growth of high-pressure phases from the melt during shock events is not diffusion-controlled. Another process, such as microturbulent transport, must be active in the crystal growth process. This result implies that the times necessary to crystallize the high-pressure phases in shocked meteorites may correspond to shock pressure durations achieved on impacts between objects 1-5 m in diameter and not, as previously inferred, =1-5 km in diameter. These results may also provide another pathway for syntheses, via shock recovery, of some high-value, high-pressure phases.

  16. Characterization of hydrothermal green quartz produced by gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Enokihara, Cyro T.; Rela, Paulo R., E-mail: cteiti@ipen.br, E-mail: prela06@yahoo.com.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Schultz-Güttler, Rainer A., E-mail: rainersgut@gmail.com [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Geociencias

    2015-07-01

    A specific variety of quartz showing a green color in nature or induced artificially by radiation gamma ({sup 60}Co) is quite rare. Only two occurrences are known today, where this type of quartz can be found: Canada, at the Thunder Bay Amethyst Mine, Ontario and Brazil, at widely scattered geode occurrences along a 600 km stretch from Quarai at Brazils southern most tip to Uberlandia in Minas Gerais. These two occurrences have been formed by strong hydrothermal activities.That way much quartz crystals showed a very fast growth history facilitating the formation of growth defects (twinning, small angle tilting, mosaic growth, striations) and the uptake of water in form of micro inclusions, molecular water, silanol (Si-OH) and OH. In the present work the material analyzed is from hydrothermal regimes found in intrusions of basaltic rocks located in the Rio Grande do Sul state. To characterize these materials, colored green by gamma rays, analyses by ICP, electron microscopy, water loss techniques and UV-VIS or NIR-FTIR spectroscopic measurements have been made. Silanol complexes are formed, which by radiation due to gamma rays form the color center NBOHC (Non-bonding Oxygen Hole Center), showing absorption between 590 to 620 nm, responsible for the green color. The water content with up to 3200 ppm by weight exceeds the amount of charge balancing cations (Fe, Al, Li). There is no correlation between water content and cations as in other color varieties. (author)

  17. Determination of volatiles produced during radiation processing in Laurus cinnamomum

    Energy Technology Data Exchange (ETDEWEB)

    Salum, D.C.; Araujo, M.M.; Fanaro, G.B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Cidade Universitaria, Av. Professor Lineu Prestes 2242, Zip code: 05508-000 Butanta, Sao Paulo, SP (Brazil); Purgatto, E. [Faculdade de Ciencias Farmaceuticas, FCF/USP, Departamento de Alimentos e Nutricao Experimental. Av. Prof. Lineu Prestes, 580 Bloco 14. CEP: 05508-900 Sao Paulo, SP (Brazil)], E-mail: epurgatt@usp.br; Villavicencio, A.L.C.H. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Cidade Universitaria, Av. Professor Lineu Prestes 2242, Zip code: 05508-000 Butanta, Sao Paulo, SP (Brazil)], E-mail: villavic@ipen.br

    2009-07-15

    In order to protect food from pathogenic microorganisms as well as increase its shelf-life, while keeping sensorial properties (e.g., odor and taste), which are important properties required by spice buyers, it is necessary to analyze volatile formation from irradiation of medicinal and food herbs. Possible changes in the odor of these herbs are evaluated by characterizing different radiation doses and effects on sensorial properties, in order to allow better application of the irradiation technology. The aim of the present study was to analyze volatile formation on cinnamon (Laurus cinnamomum) samples after gamma irradiation. These samples were irradiated into plastic packages using a {sup 60}Co facility. Radiation doses applied were 0, 5, 10, 15, 20 and 25 kGy. For the analysis of the samples, solid-phase microextraction (SPME) was applied, while for the analysis of volatile compounds, CG/MS. Spice irradiation showed the highest decrease in volatile compounds. For L. cinnamomum, the irradiation decreased volatile compounds by nearly 56% and 89.5%, respectively, comparing to volatile from a sample which had not been previously irradiated.

  18. High density terahertz frequency comb produced by coherent synchrotron radiation

    Science.gov (United States)

    Tammaro, S.; Pirali, O.; Roy, P.; Lampin, J.-F.; Ducournau, G.; Cuisset, A.; Hindle, F.; Mouret, G.

    2015-07-01

    Frequency combs have enabled significant progress in frequency metrology and high-resolution spectroscopy extending the achievable resolution while increasing the signal-to-noise ratio. In its coherent mode, synchrotron radiation is accepted to provide an intense terahertz continuum covering a wide spectral range from about 0.1 to 1 THz. Using a dedicated heterodyne receiver, we reveal the purely discrete nature of this emission. A phase relationship between the light pulses leads to a powerful frequency comb spanning over one decade in frequency. The comb has a mode spacing of 846 kHz, a linewidth of about 200 Hz, a fractional precision of about 2 × 10-10 and no frequency offset. The unprecedented potential of the comb for high-resolution spectroscopy is demonstrated by the accurate determination of pure rotation transitions of acetonitrile.

  19. Laser radiation forces in laser-produced plasmas

    International Nuclear Information System (INIS)

    Stamper, J.A.

    1975-01-01

    There are two contributions to laser radiation forces acting on the electrons. Transfer of momentum from the fields to the electrons results in a field pressure contribution and occurs whenever there is absorption or reflection. The quiver pressure contribution, associated with electron quiver motion, is due to inhomogeneous fields inducing momentum transfer within the electron system. It is shown that the ponderomotive force with force density, (epsilon-1)/8πdel 2 >, does not include the field contribution and does not lead to a general description of macroscopic processes. A theory is discussed which does give a general macroscopic description (absorption, reflection, refraction, and magnetic field generation) and which reduces to the ponderomotive force for purely sinusoidal fields in a neutral, homogeneous, nonabsorbing plasma

  20. Theoretical and experimental investigation of the Z pinch plasma as a source of power pulse of soft X radiation for generation of shock waves in condensed targets

    International Nuclear Information System (INIS)

    Grabovskij, E.V.; Smirnov, V.P.; Zakharov, S.V.; Vorob'ev, O.Yu.; Dyabilin, K.S.; Lebedev, M.E.; Fortov, V.E.; Frolov, A.A.

    1996-01-01

    Paper presents the results of theoretical analysis of processes occurring in Z-pinch plasma under conditions initiating a powerful pulse of soft X-radiation. The main attention is focused on double liner circuit designs. Estimations of power of radiation and spectrum are studied. The results are used to simulate processes occurring at generation of shock waves under the effect of soft X-radiation on the target. Experiments to generate shock waves with up to 3 Mbar amplitude pressure in lead under the effect of soft X-radiation were conducted using Angara-5 plant. 24 refs., 9 figs

  1. Influence of electromagnetic radiation produced by mobile phone on some biophysical blood properties in rats.

    Science.gov (United States)

    El-Bediwi, Abu Bakr; Saad, Mohamed; El-kott, Attall F; Eid, Eman

    2013-04-01

    Effects of electromagnetic radiation produced by mobile phone on blood viscosity, plasma viscosity, hemolysis, Osmotic fragility, and blood components of rats have been investigated. Experimental results show that there are significant change on blood components and its viscosity which affects on a blood circulation due to many body problems. Red blood cells, White blood cells, and Platelets are broken after exposure to electromagnetic radiation produced by mobile phone. Also blood viscosity and plasma viscosity values are increased but Osmotic fragility value decreased after exposure to electromagnetic radiation produced by mobile phone.

  2. The effect of ultraviolet (UV)-B radiation on primary producers

    International Nuclear Information System (INIS)

    Germ, M.

    2003-01-01

    Ozone layer in stratosphere is thinning and consequently UV-B radiation on the Earth surface is increasing. Although there is a small portion of UV-B radiation in the solar radiation, it has strong influence on organisms. Targets of UV-B radiation and protective mechanisms in primary producers are described. In the framework of the international project we studied the effect of UV-B radiation on blue-greens, algae, mosses, lichens and vascular plants on the National Institute of Biology

  3. Radiation defects produced by neutron irradiation in germanium single crystals

    International Nuclear Information System (INIS)

    Fukuoka, Noboru; Honda, Makoto; Atobe, Kozo; Yamaji, Hiromichi; Ide, Mutsutoshi; Okada, Moritami.

    1992-01-01

    The nature of defects produced in germanium single crystals by neutron irradiation at 25 K was studied by measuring the electrical resistivity. It was found that two levels located at E c -0.06 eV and E c -0.13 eV were introduced in an arsenic-doped sample. Electron traps at E c -0.10eV were observed in an indium-doped sample. The change in electrical resistivity during irradiation was also studied. (author)

  4. Repair of radiation damage caused by cyclotron-produced neutrons

    International Nuclear Information System (INIS)

    Martins, B.I.

    1979-01-01

    Hall et al. present experimental data on repair of sublethal damage in cultured mammalian cells exposed to 35 MeV neutrons and 60 Co γ rays. Hall and Kraljevic present experimental data on repair of potentially lethal damage in cultured mammalian cells exposed to 35 MeV neutrons and 210 kVp x rays. These results of Hall et al. are very difficult to explain from basic concepts in radiobiology. Contrary to Rossi, these data do not support his thesis that repair of radiation damage is dose-dependent and linear energy transfer independent. Nor do these results meet the expectations of multitarget-single hit theory which would require dose-independent repair equal to n. The observation of the same extrapolation number for neutrons and for x rays is also surprising. From the point of view of radiotherapy, the doses of interest are about 140 rad for neutrons and about 300 rad for x rays. There are no data for repair of potentially lethal damage below 800 rad for x rays and 400 rad for neutrons. The difference in survival between single and split dose is negligible up to a total of about 600 rad of x rays or of neutrons. These data of Hall et al. therefore have little significance to radiotherapists and are an enigma to radiobiologists

  5. Hybrid hydrogels produces by ionizing radiation technique for drug delivery

    International Nuclear Information System (INIS)

    Oliveira, M.J.A.; Parra, D.F.; Lugao, A.B.; Amato, V.S.

    2011-01-01

    Complete text of publication follows. Interest in the preparation of biocompatible hydrogels with various properties has increased considerably in recent years due to their versatile applications in biomedicine, biotechnology, pharmacy, agriculture and controlled release of drugs. The use of hydrogels matrices for particular drug-release applications has been investigated with the synthesis of modified polymeric hydrogel of PVAl, PEG and 0.5, 1.0 and 1.5% nano-clay. They were processed using gamma radiation from Cobalt-60 source at 25 kGy dose. The characterization of the hydrogels was conducted and toxicity was evaluated. The dried hydrogel was analyzed for thermogravimetry analysis (TGA), infrared spectroscopic analysis (FTIR), swelling in solutions of different pH and gel determinations. The membranes have no toxicity and the gel content reveals the reticulation. The nano-clay influences directly the equilibrium swelling. Acknowledgement: Support by FAPESP 09/50926-1, FAPESP Process no. 2009/18627-4 CNPq Process no. 310849/2009-8, CAPES, IPEN/CNEN.

  6. Long distance elementary measurement of the radiation dose ratio produced by neutron activation

    International Nuclear Information System (INIS)

    Zhou Changgeng; Lou Benchao; Wu Chunlei; Hu Yonghong; Li Yan

    2009-04-01

    The working principle and the structure and performances of a long distance controllable individual radiation dose ratio instrument are described. The radiation dose ratio produced by neutron activation is elementarily measured by using this instrument in the neutron generator hall with high neutron yield. When neutron yield arrives to 2 x 10 11 s -1 , the radiation dose ratio produced by neutron activation is 99.9 μSv/h in 1 h after the generator being stopped. The radiation dose ratio is reduced to 24.4 μSv/h in 39 h after the generator being stopped. When neutron yield is 3.2 x 10 10 s -1 , the radiation dose ratio produced by neutron activation is 21.9 μSv/h in 36 min, after the generator being stopped. The measurement results may provide reference for physical experimenters and neutron generator operators. (authors)

  7. Radiation therapy alone for growth hormone-producing pituitary adenomas

    Energy Technology Data Exchange (ETDEWEB)

    Plataniotis, G.A.; Kouvaris, J.R.; Vlahos, L.; Papavasiliou, C. [Athens Univ. (Greece). Dept. of Radiology

    1998-09-01

    We present our experience in the treatment of growth hormone (GH)-producing pituitary adenomas using irradiation alone. Between 1983 and 1991, 21 patients suffering from GH-secreting pituitary adenomas were treated with radiotherapy alone. Two bilateral opposing coaxial fields were used in 10 patients and in the remaining 11 a third frontovertex field was added. Treatment was given in 1.8-2 Gy daily fractions and total dose ranged between 45 and 54 Gy. Treatment was given using a cobalt unit. Four patients treated with somatostatin prior to and 14 patients treated after the end of radiotherapy experienced symptom relief for 6-28 weeks. The 5-year actuarial rate of disease control was 72%. Five out of six failed patients had macroadenomas. Hypopituitarism was observed in 5/21 (24%) patients. Whereas RT alone is effective in the treatment of microadenomas, this is not true for large infiltrative macroadenomas. (orig.)

  8. Radiation therapy alone for growth hormone-producing pituitary adenomas

    International Nuclear Information System (INIS)

    Plataniotis, G.A.; Kouvaris, J.R.; Vlahos, L.; Papavasiliou, C.

    1998-01-01

    We present our experience in the treatment of growth hormone (GH)-producing pituitary adenomas using irradiation alone. Between 1983 and 1991, 21 patients suffering from GH-secreting pituitary adenomas were treated with radiotherapy alone. Two bilateral opposing coaxial fields were used in 10 patients and in the remaining 11 a third frontovertex field was added. Treatment was given in 1.8-2 Gy daily fractions and total dose ranged between 45 and 54 Gy. Treatment was given using a cobalt unit. Four patients treated with somatostatin prior to and 14 patients treated after the end of radiotherapy experienced symptom relief for 6-28 weeks. The 5-year actuarial rate of disease control was 72%. Five out of six failed patients had macroadenomas. Hypopituitarism was observed in 5/21 (24%) patients. Whereas RT alone is effective in the treatment of microadenomas, this is not true for large infiltrative macroadenomas. (orig.)

  9. Radiation measurement of apples produced in Aomori prefecture

    International Nuclear Information System (INIS)

    Tarusawa, Kohetsu; Kudo, Kohsei; Yamadera, Akira

    2003-01-01

    The activities of seven kinds of apples produced in Aomori prefecture were measured with a high pure Ge detector set in a 15 cm-thick lead shield. The activities of 40 K were detected in all samples, but an artificial radioactive nuclide was not detected. The slices of an apple were contacted to an imaging plate for 15 days in a 15 cm-thick lead shield and cross sectional activity distributions were measured. By using the distribution map, the activities of skin, flesh and lead portion of an apple 'Ohrin' were calculated to 0.041, 0.032 and 0.046 Bq/g, respectively. This measuring system will be used for the activity estimations of the farm products, specially apples, because of that many atomic institutions are in operation and in the planning stage on Aomori prefecture. (author)

  10. Rear surface light emission measurements from laser-produced shock waves in clear and Al-coated polystyrene targets

    Science.gov (United States)

    McLean, E. A.; Deniz, A. V.; Schmitt, A. J.; Stamper, J. A.; Obenschain, S. P.; Lehecka, T.; Mostovych, A. N.; Seely, J.

    1999-08-01

    The Nike KrF laser, with its very uniform focal distributions, has been used at intensities near 10 14 W/cm 2 to launch shock waves in polystyrene targets. The rear surface visible light emission differed between clear polystyrene (CH) targets and targets with a thin (125 nm) Al coating on the rear side. The uncoated CH targets showed a relatively slowly rising emission followed by a sudden fall when the shock emerges, while the Al-coated targets showed a rapid rise in emission when the shock emerges followed by a slower fall, allowing an unambiguous determination of the time the shock arrived at the rear surface. A half-aluminized target allowed us to observe this difference in a single shot. The brightness temperature of both the aluminized targets and the non-aluminized targets was slightly below but close to rear surface temperature predictions of a hydrodynamic code. A discussion of preheat effects is given.

  11. SPECTRA OF MAGNETIC FLUCTUATIONS AND RELATIVISTIC PARTICLES PRODUCED BY A NONRESONANT WAVE INSTABILITY IN SUPERNOVA REMNANT SHOCKS

    International Nuclear Information System (INIS)

    Vladimirov, Andrey E.; Ellison, Donald C.; Bykov, Andrei M.

    2009-01-01

    We model strong forward shocks in young supernova remnants with efficient particle acceleration where a nonresonant instability driven by the cosmic ray current amplifies magnetic turbulence in the shock precursor. Particle injection, magnetic field amplification (MFA), and the nonlinear feedback of particles and fields on the bulk flow are derived consistently. The shock structure depends critically on the efficiency of turbulence cascading. If cascading is suppressed, MFA is strong, the shock precursor is stratified, and the turbulence spectrum contains several discrete peaks. These peaks, as well as the amount of MFA, should influence synchrotron X-rays, allowing observational tests of cascading and other assumptions intrinsic to the nonlinear model of nonresonant wave growth.

  12. A survey of synchrotron radiation devices producing circular or variable polarization

    International Nuclear Information System (INIS)

    Kim, K.J.

    1990-01-01

    This paper reviews the properties and operating principles of the new types of synchrotron radiation devices that produce circular polarization, or polarization that can be modulated in arbitrary fashion

  13. A comparison of the transcriptome of Drosophila melanogaster in response to entomopathogenic fungus, ionizing radiation, starvation and cold shock.

    Science.gov (United States)

    Moskalev, Alexey; Zhikrivetskaya, Svetlana; Krasnov, George; Shaposhnikov, Mikhail; Proshkina, Ekaterina; Borisoglebsky, Dmitry; Danilov, Anton; Peregudova, Darya; Sharapova, Irina; Dobrovolskaya, Eugenia; Solovev, Ilya; Zemskaya, Nadezhda; Shilova, Lyubov; Snezhkina, Anastasia; Kudryavtseva, Anna

    2015-01-01

    The molecular mechanisms that determine the organism's response to a variety of doses and modalities of stress factors are not well understood. We studied effects of ionizing radiation (144, 360 and 864 Gy), entomopathogenic fungus (10 and 100 CFU), starvation (16 h), and cold shock (+4, 0 and -4°C) on an organism's viability indicators (survival and locomotor activity) and transcriptome changes in the Drosophila melanogaster model. All stress factors but cold shock resulted in a decrease of lifespan proportional to the dose of treatment. However, stress-factors affected locomotor activity without correlation with lifespan. Our data revealed both significant similarities and differences in differential gene expression and the activity of biological processes under the influence of stress factors. Studied doses of stress treatments deleteriously affect the organism's viability and lead to different changes of both general and specific cellular stress response mechanisms.

  14. Shock pressure induced by 0.44 mu m laser radiation on aluminum targets

    Czech Academy of Sciences Publication Activity Database

    Batani, D.; Stabile, H.; Ravasio, A.; Desai, T.; Lucchini, G.; Strati, F.; Ullschmied, Jiří; Krouský, Eduard; Skála, Jiří; Králiková, Božena; Pfeifer, Miroslav; Kadlec, Christelle; Mocek, Tomáš; Präg R., Ansgar; Nishimura, H.; Ochi, Y.; Kilpio, A.; Shashkov, E.; Stuchebrukhov, I.; Vovchenko, V.; Krasuyk, I.

    2003-01-01

    Roč. 21, č. 4 (2003), s. 481-487 ISSN 0263-0346 R&D Projects: GA MŠk LN00A100 Grant - others:HPRI-CT(XX) 1999-00053 Institutional research plan: CEZ:AV0Z2043910 Keywords : rear target luminosity, shock pressure, shock waves Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.646, year: 2003

  15. Radiation

    International Nuclear Information System (INIS)

    2013-01-01

    The chapter one presents the composition of matter and atomic theory; matter structure; transitions; origin of radiation; radioactivity; nuclear radiation; interactions in decay processes; radiation produced by the interaction of radiation with matter

  16. VizieR Online Data Catalog: Effects of preionization in radiative shocks (Sutherland+, 2017)

    Science.gov (United States)

    Sutherland, R. S.; Dopita, M. A.

    2017-06-01

    In this paper we treat the preionization problem in shocks over the velocity range 10shock-precursor parameter, {Psi}=Q/vs, where Q is the ionization parameter of the UV photons escaping upstream. This parameter determines both the temperature and the degree of ionization of the gas entering the shock. In increasing velocity, the shock solution regimes are cold neutral precursors (vs<~40km/s), warm neutral precursors (40<~vs<~75km/s), warm partly ionized precursors (75<~vs<~120km/s), and fast shocks in which the preshock gas is in photoionization equilibrium and is fully ionized. The main effect of a magnetic field is to push these velocity ranges to higher values and to limit the postshock compression. In order to facilitate comparison with observations of shocks, we provide a number of convenient scaling relationships for parameters, such as postshock temperature, compression factors, cooling lengths, and Hβ and X-ray luminosity. (4 data files).

  17. The induced expression of heat shock proteins as a part of the early cellular response to gamma radiation

    International Nuclear Information System (INIS)

    Stankova, K.; Ivanova, K.; Georgieva, R.; Rupova, I.; Boteva, R.

    2008-01-01

    A variety of stressful stimuli including gamma radiation can induce increase in the synthesis of heat shock proteins (Hsp). This family of molecular chaperones includes members with molecular masses ranging from 10 to 150 kDa and has been identified in all organisms from bacteria to humans. Hsp70 chaperones are very important. The present study aimed to characterize the radiation-induced changes in Hsp70 synthesis in human lymphocytes as a part of the early cellular response to gamma irradiation. The expression of Hsp70 was determined with Western blot and the radiation-induced apoptotic changes were registered by staining with fluorescent dyes. Part of the experiments were performed in the presence of the organic solvent DMSO. At low concentrations this reagent shows antioxidant activity and can reduce the level of the radiation-induced oxidant stress which determines the predominant biological effects of the ionizing radiation. Irradiation with 0.5 to 8 Gy caused statistically significant increase in the synthesis of Hsp70 which was strongest after irradiation with 4 Gy. In the range 0.5-2 Gy the enhancement of the radiation-induced synthesis of Hsp70 reached 60%. Our experimental results characterize changes in the Hsp70 synthesis after gamma irradiation as a part of the early cellular stress response in lymphocytes. (authors)

  18. Effective radiation exposure evaluation during a one year follow-up of urolithiasis patients after extracorporeal shock wave lithotripsy.

    Science.gov (United States)

    Kaynar, Mehmet; Tekinarslan, Erdem; Keskin, Suat; Buldu, İbrahim; Sönmez, Mehmet Giray; Karatag, Tuna; Istanbulluoglu, Mustafa Okan

    2015-01-01

    To determine and evaluate the effective radiation exposure during a one year follow-up of urolithiasis patients following the SWL (extracorporeal shock wave lithotripsy) treatment. Total Effective Radiation Exposure (ERE) doses for each of the 129 patients: 44 kidney stone patients, 41 ureter stone patients, and 44 multiple stone location patients were calculated by adding up the radiation doses of each ionizing radiation session including images (IVU, KUB, CT) throughout a one year follow-up period following the SWL. Total mean ERE values for the kidney stone group was calculated as 15, 91 mSv (5.10-27.60), for the ureter group as 13.32 mSv (5.10-24.70), and in the multiple stone location group as 27.02 mSv (9.41-54.85). There was no statistically significant differences between the kidney and ureter groups in terms of the ERE dose values (p = 0.221) (p >0.05). In the comparison of the kidney and ureter stone groups with the multiple stone location group; however, there was a statistically significant difference (p = 0.000) (p ionized radiation, different imaging modalities with low dose and/or totally without a dose should be employed in the diagnosis, treatment, and follow-up bearing the aim to optimize diagnosis while minimizing the radiation dose as much as possible.

  19. Power Difference in Spectrum of Sound Radiation before and after Break of Phantom by Piezoelectric Extracorporeal Shock Wave Lithotriptor

    Science.gov (United States)

    Kanai, Hiroshi; Jang, Yun-Seok; Chubachi, Noriyoshi; Tanahashi, Yoshikatsu

    1994-05-01

    This paper investigates the difference in the spectrum of sound radiated before and after the break of a phantom at a focal point of the piezoelectric extracorporeal shock wave lithotriptor (ESWL) in order to identify the break time or to examine whether a calculus exists exactly at the focal point or not. From the preliminary experiments using a piece of chalk as a phantom of a calculus to measure the sound radiated when impact is applied to the chalk by an impact hammer, it is found that the bending vibration component of the vibration is exhibited in the spectrum of sound. However, for small-sized chalk shorter than 3 cm, the peak frequency of the bending vibration is higher than 20 kHz. From the experiments using a piezoeletric ESWL, it is found that there is clear difference in the power spectra among the sound radiated before the break, that radiated just after the break in the breaking process, and that radiated when the chalk does not exist at the focal point of the ESWL. These characteristics will be effective for the examination of the existence of the calculus at the focal point.

  20. Propagation of a cylindrical shock wave in a rotating dusty gas with heat conduction and radiation heat flux

    International Nuclear Information System (INIS)

    Vishwakarma, J P; Nath, G

    2010-01-01

    A self-similar solution for the propagation of a cylindrical shock wave in a dusty gas with heat conduction and radiation heat flux, which is rotating about the axis of symmetry, is investigated. The shock is assumed to be driven out by a piston (an inner expanding surface) and the dusty gas is assumed to be a mixture of non-ideal gas and small solid particles. The density of the ambient medium is assumed to be constant. The heat conduction is expressed in terms of Fourier's law and radiation is considered to be of diffusion type for an optically thick grey gas model. The thermal conductivity K and the absorption coefficient α R are assumed to vary with temperature and density. Similarity solutions are obtained, and the effects of variation of the parameter of non-idealness of the gas in the mixture, the mass concentration of solid particles and the ratio of density of solid particles to the initial density of the gas are investigated.

  1. Magnetogasdynamics shock waves in a rotational axisymmetric non-ideal gas with increasing energy and conductive and radiative heat-fluxes

    Science.gov (United States)

    Nath, Gorakh

    2016-07-01

    Self-similar solutions are obtained for one-dimensional adiabatic flow behind a magnetogasdynamics cylindrical shock wave propagating in a rotational axisymmetric non ideal gas with increasing energy and conductive and radiative heat fluxes in presence of an azimuthal magnetic field. The fluid velocities and the azimuthal magnetic field in the ambient medium are assume to be varying and obeying power laws. In order to find the similarity solutions the angular velocity of the ambient medium is taken to be decreasing as the distance from the axis increases. The heat conduction is expressed in terms of Fourier's law and the radiation is considered to be the diffusion type for an optically thick grey gas model. The thermal conductivity and the absorption coefficient are assumed to vary with temperature and density. The effects of the presence of radiation and conduction, the non-idealness of the gas and the magnetic field on the shock propagation and the flow behind the shock are investigated.

  2. A MODEL FOR PRODUCING STABLE, BROADBAND TERAHERTZ COHERENT SYNCHROTRON RADIATION IN STORAGE RINGS

    International Nuclear Information System (INIS)

    Sannibale, Fernando; Byrd, John M.; Loftsdottir, Agusta; Martin, MichaelC.; Venturini, Marco

    2003-01-01

    We present a model for producing stable broadband coherent synchrotron radiation (CSR) in the terahertz frequency region in an electron storage ring. The model includes distortion of bunch shape from the synchrotron radiation (SR), enhancing higher frequency coherent emission and limits to stable emission due to a microbunching instability excited by the SR. We use this model to optimize the performance of a source for CSR emission

  3. Taste aversion learning produced by combined treatment with subthreshold radiation and lithium chloride

    International Nuclear Information System (INIS)

    Rabin, B.M.; Hunt, W.A.; Lee, J.

    1987-01-01

    These experiments were designed to determine whether treatment with two subthreshold doses of radiation or lithium chloride, either alone or in combination, could lead to taste aversion learning. The first experiment determined the thresholds for a radiation-induced taste aversion at 15-20 rad and for lithium chloride at 0.30-0.45 mEq/kg. In the second experiment it was shown that exposing rats to two doses of 15 rad separated by up to 3 hr produced a taste aversion. Treatment with two injections of lithium chloride (0.30 mEq/kg) did not produce a significant reduction in preference. Combined treatment with radiation and lithium chloride did produce a taste aversion when the two treatments were administered within 1 hr of each other. The results are discussed in terms of the implications of these findings for understanding the nature of the unconditioned stimuli leading to the acquisition of a conditioned taste aversion

  4. CARS Measurement of Vibrational/Rotational Temperatures with Total Radiation Visualization behind Strong Shock Waves of 5-7 km/s

    Science.gov (United States)

    Sakurai, K.; Bindu, V. Hima; Niinomi, S.; Ota, M.; Maeno, K.

    2011-05-01

    In the development of aerospace technology the design of space vehicles is important in phase of reentry flight. The space vehicles reenter into the atmosphere with range of 6-8 km/s. The non-equilibrium flow with radiative heating from strongly shocked air ahead of the vehicles plays an important role on the heat flux to the wall surface structure as well as convective heating. The experimental data for re-entry analyses, however, have remained in classical level. Recent development of optical instruments enables us to have novel approach of diagnostics to the re-entry problems. We employ the CARS (Coherent Anti-Stokes Raman Spectroscopy) method for measurement of real gas temperatures of N2 with radiation of the strong shock wave. The CARS signal can be acquired even in the strong radiation area behind the strong shock waves. In addition, we try to use the CCD camera to obtain 2D images of total radiation simultaneously. The strong shock wave in front of the reentering space vehicles is experimentally realigned by free-piston, double-diaphragm shock tube with low density test gas.

  5. Study of extremely low frequency electromagnetic field (ELF EMF) radiation produced by consumer products

    International Nuclear Information System (INIS)

    Roha Tukimin; Ahmad Fazli Ahmad Sanusi; Rozaimah Abd Rahim; Mohd Yusof Mohd Ali; Mohamad Amirul Nizam Mohamad Thari

    2006-01-01

    Extremely low frequency electromagnetic field ( ELF EMF) radiation falls under category of non-ionising radiation (NIR).ELF EMF consists of electric and magnetic fields. Excessive exposure to ELF EMF radiation may cause biological and health effects to human beings such as behavioral changes, stochastic and as initiator of cancer. In daily life, the main source of extremely low frequency electromagnetic radiation are consumer products in our home and office. Due to its ability to cause hazard, a study of ELF EMF radiation produced by consumer product was conducted. For this preliminary study, sample of 20 types electrical appliances were selected. The measurement was covered electric and magnetic field strength produced by the sample. PMM model EHP50A were used for measurement and data analysis. The results were compared with the permissible limits recommended by International Commission of Non-Ionising Radiation Protection (ICNIRP) for members of public (1000 mGauss and 5000 V/m). The results showed that all tested sample produced magnetic and electric field but still under the permissible limit recommended by ICNIRP. Besides that we found that field strengths can be very high at closer distance to the sample. (Author)

  6. Monte-Carlo study on primary knock-on atom energy spectrum produced by neutron radiation

    International Nuclear Information System (INIS)

    Zhou Wei; Liu Yongkang; Deng Yongjun; Ma Jimin

    2012-01-01

    Computational method on energy distribution of primary knock-on atom (PKA) produced by neutron radiation was built in the paper. Based on the DBCN card in MCNP, reaction position, reaction type and energy transfer between neutrons and atoms were recorded. According to statistic of these data, energy and space distributions of PKAs were obtained. The method resolves preferably randomicity of random number and efficiency of random sampling computation. The results show small statistical fluctuation and well statistical. Three-dimensional figure of energy and space distribution of PKAs were obtained, which would be important to evaluate radiation capability of materials and study radiation damage by neutrons. (authors)

  7. Two-temperature hydrodynamic expansion and coupling of strong elastic shock with supersonic melting front produced by ultrashort laser pulse

    International Nuclear Information System (INIS)

    Inogamov, Nail A; Khokhlov, Viktor A; Zhakhovsky, Vasily V; Khishchenko, Konstantin V; Demaske, Brian J; Oleynik, Ivan I

    2014-01-01

    Ultrafast processes, including nonmonotonic expansion of material into vacuum, supersonic melting and generation of super-elastic shock wave, in a surface layer of metal irradiated by an ultrashort laser pulse are discussed. In addition to the well-established two-temperature (2T) evolution of heated layer a new effect of electron pressure gradient on early stage of material expansion is studied. It is shown that the expanding material experiences an unexpected jump in flow velocity in a place where stress exceeds the effective tensile strength provided by used EoS of material. Another 2T effect is that supersonic propagation of homogeneous melting front results in distortion of spatial profile of ion temperature, which later imprints on ion pressure profile transforming in a super-elastic shock wave with time.

  8. Selection of daunorubicin-producing strain S. Coeruleorubidus by plasma radiation technology

    International Nuclear Information System (INIS)

    Jiang Shichun; Wu Jianping; Bai Hua

    2001-01-01

    The authors reported the results of mutagenesis by nitrogen plasma radiation with energy from 65 to 80 keV and dose from 9.6 x 10 9 to 1.5 x 10 11 /cm 2 in antineoplastic antibiotics daunorubicin-producing S. Coeruleorubidus. The relationship between death rate and radiation dose was formulated by computer and the formula. It was fit to a biological single-hit curve. The obtained high-producing mutagenic strain 137 was tested for its production property. The result showed that it could increase the daunorubicin potency by 25.8% in productive tanks of fermentation

  9. Estimating model parameters for an impact-produced shock-wave simulation: Optimal use of partial data with the extended Kalman filter

    International Nuclear Information System (INIS)

    Kao, Jim; Flicker, Dawn; Ide, Kayo; Ghil, Michael

    2006-01-01

    This paper builds upon our recent data assimilation work with the extended Kalman filter (EKF) method [J. Kao, D. Flicker, R. Henninger, S. Frey, M. Ghil, K. Ide, Data assimilation with an extended Kalman filter for an impact-produced shock-wave study, J. Comp. Phys. 196 (2004) 705-723.]. The purpose is to test the capability of EKF in optimizing a model's physical parameters. The problem is to simulate the evolution of a shock produced through a high-speed flyer plate. In the earlier work, we have showed that the EKF allows one to estimate the evolving state of the shock wave from a single pressure measurement, assuming that all model parameters are known. In the present paper, we show that imperfectly known model parameters can also be estimated accordingly, along with the evolving model state, from the same single measurement. The model parameter optimization using the EKF can be achieved through a simple modification of the original EKF formalism by including the model parameters into an augmented state variable vector. While the regular state variables are governed by both deterministic and stochastic forcing mechanisms, the parameters are only subject to the latter. The optimally estimated model parameters are thus obtained through a unified assimilation operation. We show that improving the accuracy of the model parameters also improves the state estimate. The time variation of the optimized model parameters results from blending the data and the corresponding values generated from the model and lies within a small range, of less than 2%, from the parameter values of the original model. The solution computed with the optimized parameters performs considerably better and has a smaller total variance than its counterpart using the original time-constant parameters. These results indicate that the model parameters play a dominant role in the performance of the shock-wave hydrodynamic code at hand

  10. The Shock/Shear platform for planar radiation-hydrodynamics experiments on the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Doss, F. W., E-mail: fdoss@lanl.gov; Kline, J. L.; Flippo, K. A.; Perry, T. S.; DeVolder, B. G.; Tregillis, I.; Loomis, E. N.; Merritt, E. C.; Murphy, T. J.; Welser-Sherrill, L.; Fincke, J. R. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2015-05-15

    An indirectly-driven shock tube experiment fielded on the National Ignition Facility (NIF) was used to create a high-energy-density hydrodynamics platform at unprecedented scale. Scaling up a shear-induced mixing experiment previously fielded at OMEGA, the NIF shear platform drives 130 μm/ns shocks into a CH foam-filled shock tube (∼ 60 mg/cc) with interior dimensions of 1.5 mm diameter and 5 mm length. The pulse-shaping capabilities of the NIF are used to extend the drive for >10 ns, and the large interior tube volumes are used to isolate physics-altering edge effects from the region of interest. The scaling of the experiment to the NIF allows for considerable improvement in maximum driving time of hydrodynamics, in fidelity of physics under examination, and in diagnostic clarity. Details of the experimental platform and post-shot simulations used in the analysis of the platform-qualifying data are presented. Hydrodynamic scaling is used to compare shear data from OMEGA with that from NIF, suggesting a possible change in the dimensionality of the instability at late times from one platform to the other.

  11. Self similar flow behind an exponential shock wave in a self-gravitating, rotating, axisymmetric dusty gas with heat conduction and radiation heat flux

    Science.gov (United States)

    Bajargaan, Ruchi; Patel, Arvind

    2018-04-01

    One-dimensional unsteady adiabatic flow behind an exponential shock wave propagating in a self-gravitating, rotating, axisymmetric dusty gas with heat conduction and radiation heat flux, which has exponentially varying azimuthal and axial fluid velocities, is investigated. The shock wave is driven out by a piston moving with time according to an exponential law. The dusty gas is taken to be a mixture of a non-ideal gas and small solid particles. The density of the ambient medium is assumed to be constant. The equilibrium flow conditions are maintained and energy is varying exponentially, which is continuously supplied by the piston. The heat conduction is expressed in the terms of Fourier's law, and the radiation is assumed of diffusion type for an optically thick grey gas model. The thermal conductivity and the absorption coefficient are assumed to vary with temperature and density according to a power law. The effects of the variation of heat transfer parameters, gravitation parameter and dusty gas parameters on the shock strength, the distance between the piston and the shock front, and on the flow variables are studied out in detail. It is interesting to note that the similarity solution exists under the constant initial angular velocity, and the shock strength is independent from the self gravitation, heat conduction and radiation heat flux.

  12. Radiation pretreatment of cellulosic wastes and immobilization of cells producing cellulase for their conversion to glucose

    International Nuclear Information System (INIS)

    Kumakura, Minoru; Kaetsu, Isao

    1988-01-01

    Radiation pretreatment of cellulosic wastes such as saw dust and chaff was studied by using electron beam accelerator, in which irradiation effect was increased by increasing irradiation dose and dose rate, by after heating irradiated materials at 100∼140deg C, and by irradiation in the addition of alkaline solution. Trichoderma reesei cells producing cellulase were immobilized by using fibrous porous carrier obtained from radiation polymerization. The filter paper, cellobiose, and CMC activities in the immobilized growing cells were higher than those in free cells. The activity in the immobilized cells obtained with hydrophobic carrier was higher than that obtained with hydrophilic one. Durability of the immobilized cells was examined by repeated batch culture. It was found that the enzyme solution produced in the culture of the immobilized cells can hydrolyze effectively saw dust pretreated by radiation. (author)

  13. Finite element method (FEM) model of the mechanical stress on phospholipid membranes from shock waves produced in nanosecond electric pulses (nsEP)

    Science.gov (United States)

    Barnes, Ronald; Roth, Caleb C.; Shadaram, Mehdi; Beier, Hope; Ibey, Bennett L.

    2015-03-01

    The underlying mechanism(s) responsible for nanoporation of phospholipid membranes by nanosecond pulsed electric fields (nsEP) remains unknown. The passage of a high electric field through a conductive medium creates two primary contributing factors that may induce poration: the electric field interaction at the membrane and the shockwave produced from electrostriction of a polar submersion medium exposed to an electric field. Previous work has focused on the electric field interaction at the cell membrane, through such models as the transport lattice method. Our objective is to model the shock wave cell membrane interaction induced from the density perturbation formed at the rising edge of a high voltage pulse in a polar liquid resulting in a shock wave propagating away from the electrode toward the cell membrane. Utilizing previous data from cell membrane mechanical parameters, and nsEP generated shockwave parameters, an acoustic shock wave model based on the Helmholtz equation for sound pressure was developed and coupled to a cell membrane model with finite-element modeling in COMSOL. The acoustic structure interaction model was developed to illustrate the harmonic membrane displacements and stresses resulting from shockwave and membrane interaction based on Hooke's law. Poration is predicted by utilizing membrane mechanical breakdown parameters including cortical stress limits and hydrostatic pressure gradients.

  14. Experimental and theoretical investigation of radiation and dynamics properties in laser-produced carbon plasmas

    Science.gov (United States)

    Min, Qi; Su, Maogen; Wang, Bo; Cao, Shiquan; Sun, Duixiong; Dong, Chenzhong

    2018-05-01

    The radiation and dynamics properties of laser-produced carbon plasma in vacuum were studied experimentally with aid of a spatio-temporally resolved emission spectroscopy technique. In addition, a radiation hydrodynamics model based on the fluid dynamic equations and the radiative transfer equation was presented, and calculation of the charge states was performed within the time-dependent collisional radiative model. Detailed temporal and spatial evolution behavior about plasma parameters have been analyzed, such as velocity, electron temperature, charge state distribution, energy level population, and various atomic processes. At the same time, the effects of different atomic processes on the charge state distribution were examined. Finally, the validity of assuming a local thermodynamic equilibrium in the carbon plasma expansion was checked, and the results clearly indicate that the assumption was valid only at the initial (applicable near the plasma boundary because of a sharp drop of plasma temperature and electron density.

  15. Miniature shock tube for laser driven shocks.

    Science.gov (United States)

    Busquet, Michel; Barroso, Patrice; Melse, Thierry; Bauduin, Daniel

    2010-02-01

    We describe in this paper the design of a miniature shock tube (smaller than 1 cm(3)) that can be placed in a vacuum vessel and allows transverse optical probing and longitudinal backside extreme ultraviolet emission spectroscopy in the 100-500 A range. Typical application is the study of laser launched radiative shocks, in the framework of what is called "laboratory astrophysics."

  16. Effect of Geranylgeranylacetone on Ultraviolet Radiation Type B-Induced Cataract in Heat-Shock Transcription Factor 1 Heterozygous Mouse.

    Science.gov (United States)

    Ogasawara, Satoshi; Hashizume, Kouhei; Okuno, Takashi; Imaizumi, Toshiyasu; Inomata, Yui; Tezuka, Yu; Sanbe, Atushi; Kurosaka, Daijiro

    2017-05-01

    We investigated whether heat-shock transcription factor 1 (HSF1) was involved in ultraviolet radiation type B (UVR-B)-induced lens opacity (cataract) using HSF1 heterozygous mice. We also examined the effects of geranylgeranylacetone (GGA), an inducer of heat-shock proteins via activation of HSF, on the UVR-B-induced cataract. Male HSF1 +/- and WT mice were unilaterally exposed to UVR-B (total: 1200mJ) at 16 weeks of age. At 48 h after the last UVR-B irradiation, the lens was isolated and the induction of the cataract was quantified as the cataract area ratio (opacity area/anterior capsule). GGA was orally administered at a dosage of 500 mg/kg once a day for two days before the first UVR-B exposure until the end of the experiment (21days in total). The HSF1 expression was more greatly decreased in the lens from HSF1 +/- mice than in that from WT mice (p B exposure could mainly induce cataracts in the anterior capsule in both HSF1 +/- and WT mice, while the opacity of the lens was markedly enhanced in HSF 1+/- mice compared to that in WT mice(p (0.01). GGA treatment could prevent the induction of lens opacity by UVR-B exposure in both WT and HSF1 +/- mice as compared with the non-administration group (p B radiation was seen in lens protein levels of αA-crystallin, αB-crystallin, or γ-crystallin with or without GGA administration among all groups of mice. In contrast to the crystallins, the lens protein level of HSP25 was decreased by UVR-B exposure in both HSF1 +/- and WT mice, and was significantly recovered in WT mice by the GGA treatment (p B-induced cataracts, possibly via regulation of HSPs such as HSP25.

  17. Radiative bow shock wave (?) driven by nuclear ejecta in a Seyfert galaxy

    International Nuclear Information System (INIS)

    Wilson, A.S.; Ulvestad, J.S.; California Institute of Technology, Pasadena)

    1987-01-01

    New VLA maps at 2 cm of the 13-arcsec-scale linear radio source in the center of NGC 1068 are described. The northeast lobe shows a limb-brightened conical morphology, very sharp leading edges, and a magnetic field running parallel to these edges. The spectral index between 2 and 6 cm in these line-brightened regions is near 1.0. The northeast subpeak has a very steep radio spectrum between 18 and 2 cm which is attributed to inverse Compton losses of the relativistic electrons on the infrared photons. The spectral indices in the southwest lobe lie in the range 0.9-1.5 except in its northern parts, where a much larger index is found. The northeast lobe radio emission could arise in either the cocoon of old jet material which has passed through the internal shock in the ejecta and blown out to either side, or in interstellar material compressed by a bow shock wave driven into the galactic ISM. 45 references

  18. Doping of semiconductors using radiation defects produced by irradiation with protons and alpha particles

    International Nuclear Information System (INIS)

    Kozlov, V.A.; Kozlovski, V.V.

    2001-01-01

    One of the modern methods for modifying semiconductors using beams of protons and alpha particles is analyzed; this modification is accomplished by the controlled introduction of radiation defects into the semiconductor. It is shown that doping semiconductors with radiation defects produced by irradiation with light ions opens up fresh opportunities for controlling the properties of semiconducting materials and for the development of new devices designed for optoelectronics, microelectronics, and nanoelectronics based on these materials; these devices differ favorably from those obtained by conventional doping methods, i.e., by diffusion, epitaxy, and ion implantation

  19. Theory of electron degradation and yields of initial molecular species produced by ionizing radiation

    International Nuclear Information System (INIS)

    Inokuti, M.; Dillon, M.A.; Kimura, M.

    1987-01-01

    Ionizing radiations generate in matter a large number of energetic electrons, which in turn collide with molecules in matter, produce ions and excited states, and thereby degrade in energy. The description of the consequences of many collision processes to the electrons and to matter is the goal of the electron degradation theory. They summarize the current understanding of this topic, which is important as a basis of radiation chemistry and biology. In addition, they present an initial report of their new work, namely, a generalization of the Spencer-Fano theory to time-dependent cases

  20. Beam diagnostics using transition radiation produced by a 100 Mev electron beam

    International Nuclear Information System (INIS)

    Jablonka, M.; Leroy, J.; Hanus, X.; Derost, J.C.; Wartski, L.

    1991-01-01

    We report on several experiments using the optical transition radiation (OTR) produced by a 100 MeV electron beam. In using a sensitive video camera coupled with a digital image processing system an accurate and simple beam profile monitor has been devised. In measuring with a photo-multiplier the radiation emitted in a small solid angle around the direction of the OTR emission, a signal very sensitive to beam energy variations has been obtained. These experiments have been carried out on the Saclay ALS linac

  1. Biomass shock pretreatment

    Science.gov (United States)

    Holtzapple, Mark T.; Madison, Maxine Jones; Ramirez, Rocio Sierra; Deimund, Mark A.; Falls, Matthew; Dunkelman, John J.

    2014-07-01

    Methods and apparatus for treating biomass that may include introducing a biomass to a chamber; exposing the biomass in the chamber to a shock event to produce a shocked biomass; and transferring the shocked biomass from the chamber. In some aspects, the method may include pretreating the biomass with a chemical before introducing the biomass to the chamber and/or after transferring shocked biomass from the chamber.

  2. Final Report for Project DE-SC0006958: "An Investigation of the Effects of magnetic Fields and Collisionality on Shock Formation in Radiatively Cooled Plasma Flows"

    Energy Technology Data Exchange (ETDEWEB)

    Bott-Suzuki, Simon

    2014-11-05

    We have developed a new experimental platform to study bow-shock formation in plasma flows generated using an inverse wire array z-pinch. We have made significant progress on the analysis of both hydrodynamic and magnetized shocks using this system. The hydrodynamic experiments show formation of a well-defined Mach cone, and highly localized shock strong associated with radiative losses and rapidly cooling over the shock. Magnetized shocks show that the balance of magnetic and ram pressures dominate the evolution of the shock region, generating a low plasma beta void around the target. Manuscripts are in preparation for publication on both these topics. We have also published the development of a novel diagnostic method which allow recovery of interferometry and self-emission data along the same line of sight. Finally, we have carried out work to integrate a kinetic routine with the 3D MHD code Gorgon, however it remains to complete this process. Both undergraduate and graduate students have been involved in both the experimental work and publications.

  3. Observations of visual sensations produced by Cerenkov radiation from high-energy electrons

    International Nuclear Information System (INIS)

    Steidley, K.D.; Eastman, R.M.; Stabile, R.J.

    1989-01-01

    Ten cancer patients whose eyes were therapeutically irradiated with 6-18 MeV electrons reported visual light sensations. Nine reported seeing blue light and one reported seeing white light. Controls reported seeing no light. Additionally, tests with patients ruled out the x-ray contamination of the electron beam as being important. The photon yield due to Cerenkov radiation produced by radium and its daughters for both electrons and gamma rays was calculated; it was found to account for a turn-of-the-century human observation of the radium phosphene. We conclude that the dominant mechanism of this phosphene is Cerenkov radiation, primarily from betas. From our own patient data, based on the color seen and the Cerenkov production rates, we conclude that the dominant mechanism is Cerenkov radiation and that high-energy electrons are an example of particle induced visual sensations

  4. Systems and methods for imaging using radiation from laser produced plasmas

    Science.gov (United States)

    Renard-Le Galloudec, Nathalie; Cowan, Thomas E.; Sentoku, Yasuhiko; Rassuchine, Jennifer

    2009-06-30

    In particular embodiments, the present disclosure provides systems and methods for imaging a subject using radiation emitted from a laser produced plasma generating by irradiating a target with a laser. In particular examples, the target includes at least one radiation enhancing component, such as a fluor, cap, or wire. In further examples, the target has a metal layer and an internal surface defining an internal apex, the internal apex of less than about 15 .mu.m, such as less than about 1 .mu.m. The targets may take a variety of shapes, including cones, pyramids, and hemispheres. Certain aspects of the present disclosure provide improved imaging of a subject, such as improved medical images of a radiation dose than typical conventional methods and systems.

  5. 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)

  6. Amelioration of radiation induced oxidative stress using water soluble chitosan produced by Aspergillus niger

    International Nuclear Information System (INIS)

    EL-Sonbaty, S.M.; Swailam, H.M.; Noaman, E.

    2012-01-01

    Chitosan is a natural polysaccharide synthesized by a great number of living organisms and considered as a source of potential bioactive material and has many biological applications which are greatly affected by its solubility in neutral ph. In this study low molecular weight water soluble chitosan was prepared by chemical degradation of chitosan produced by Aspergillus niger using H 2 O 2 . Chitosan chemical structure was detected before and after treatment using FTIR spectrum, and its molecular weight was determined by its viscosity using viscometer. Its antioxidant activity against gamma radiation was evaluated in vivo using rats. Rats were divided into 4 groups; group 1: control, group 2: exposed to acute dose of gamma radiation (6 Gy), group 3: received water soluble chitosan, group 4: received water soluble chitosan then exposed to gamma radiation as group 2. Gamma radiation significantly increased malonaldehyde, decreased glutathione concentration, activity of superoxide dismutase, catalase, and glutatione peroxidase, while significantly increase the activity of alanine transferase, aspartate transferase, urea and creatinine concentration. Administration of water soluble chitosan has ameliorated induced changes caused by gamma radiation. It could be concluded that water soluble chitosan by scavenging free radicals directly or indirectly may act as a potent radioprotector against ionizing irradiation.

  7. Pressurized thermal shock. CNA-I behavior when a hot leg breaks of 50 cm2 is produced

    International Nuclear Information System (INIS)

    Rosso, Ricardo D.; Ventura, Mirta A.

    2002-01-01

    Pressurized thermal shock (PTS) phenomena in the CNA-I pressurize heavy water reactor is analyzed in this paper. The initiating event is a hypothetical 50 cm 2 break of the line connecting the pressurizer and the primary system. The calculation procedure for obtaining the local thermal-hydraulic parameters in the reactor pressure vessel downcomer is described firstly. Results obtained lead to conclusions in different subjects. The first conclusion is that a simple tool of easy application is available to analyze PTS phenomena in cases of breaks in the primary system in cold and hot legs. This methodology is fully independent of the methodology utilized by the Utility. Another important conclusion comes from the analysis of the temperature evolution of the fluid below the cold leg level in the RPV downcomer, as a function of the T HPI temperature of the TJ system injected water from. It is also concluded that the results obtained with the methodology adopted agree with the ones obtained with the methodologies validated against experiments in the UPTF facility. It is possible to observe that when T HPI increase, the conditions suitable for PTS occurrence in a LOCA accident tend to diminish. The maximum value to the T HPI may be fixed from the maximum temperature allowed to preserve the structural integrity of the fuel cladding. (author)

  8. 2-Shock layered tuning campaign

    Science.gov (United States)

    Masse, Laurent; Dittrich, T.; Khan, S.; Kyrala, G.; Ma, T.; MacLaren, S.; Ralph, J.; Salmonson, J.; Tipton, R.; Los Alamos Natl Lab Team; Lawrence Livermore Natl Lab Team

    2016-10-01

    The 2-Shock platform has been developed to maintain shell sphericity throughout the compression phase of an indirect-drive target implosion and produce a stagnating hot spot in a quasi 1D-like manner. A sub-scale, 1700 _m outer diameter, and thick, 200 _m, uniformly Silicon doped, gas-filled plastic capsule is driven inside a nominal size 5750 _m diameter ignition hohlraum. The hohlraum fill is near vacuum to reduce back-scatter and improve laser/drive coupling. A two-shock pulse of about 1 MJ of laser energy drives the capsule. The thick capsule prevents ablation front feed-through to the imploded core. This platform has demonstrated its efficiency to tune a predictable and reproducible 1-D implosion with a nearly round shape. It has been shown that the high foot performance was dominated by the local defect growth due to the ablation front instability and by the hohlraum radiation asymmetries. The idea here is to take advantage of this 2-Shock platform to design a 1D-like layered implosion and eliminates the deleterious effects of radiation asymmetries and ablation front instability growth. We present the design work and our first experimental results of this near one-dimensional 2-Shock layered design. This work was performed under the auspices of the Lawrence Livermore National Security, LLC, (LLNS) under Contract No. DE-AC52-07NA27344.

  9. First results of radiation-driven, layered deuterium-tritium implosions with a 3-shock adiabat-shaped drive at the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Smalyuk, V. A.; Robey, H. F.; Döppner, T.; Jones, O. S.; Milovich, J. L.; Bachmann, B.; Baker, K. L.; Berzak Hopkins, L. F.; Bond, E.; Callahan, D. A.; Casey, D. T.; Celliers, P. M.; Cerjan, C.; Clark, D. S.; Dixit, S. N.; Edwards, M. J.; Haan, S. W.; Hamza, A. V.; Hurricane, O. A.; Jancaitis, K. S. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); and others

    2015-08-15

    Radiation-driven, layered deuterium-tritium plastic capsule implosions were carried out using a new, 3-shock “adiabat-shaped” drive on the National Ignition Facility. The purpose of adiabat shaping is to use a stronger first shock, reducing hydrodynamic instability growth in the ablator. The shock can decay before reaching the deuterium-tritium fuel leaving it on a low adiabat and allowing higher fuel compression. The fuel areal density was improved by ∼25% with this new drive compared to similar “high-foot” implosions, while neutron yield was improved by more than 4 times, compared to “low-foot” implosions driven at the same compression and implosion velocity.

  10. Thermophysical properties of multi-shock compressed dense argon.

    Science.gov (United States)

    Chen, Q F; Zheng, J; Gu, Y J; Chen, Y L; Cai, L C; Shen, Z J

    2014-02-21

    In contrast to the single shock compression state that can be obtained directly via experimental measurements, the multi-shock compression states, however, have to be calculated with the aid of theoretical models. In order to determine experimentally the multiple shock states, a diagnostic approach with the Doppler pins system (DPS) and the pyrometer was used to probe multiple shocks in dense argon plasmas. Plasma was generated by a shock reverberation technique. The shock was produced using the flyer plate impact accelerated up to ∼6.1 km/s by a two-stage light gas gun and introduced into the plenum argon gas sample, which was pre-compressed from the environmental pressure to about 20 MPa. The time-resolved optical radiation histories were determined using a multi-wavelength channel optical transience radiance pyrometer. Simultaneously, the particle velocity profiles of the LiF window was measured with multi-DPS. The states of multi-shock compression argon plasma were determined from the measured shock velocities combining the particle velocity profiles. We performed the experiments on dense argon plasmas to determine the principal Hugonoit up to 21 GPa, the re-shock pressure up to 73 GPa, and the maximum measure pressure of the fourth shock up to 158 GPa. The results are used to validate the existing self-consistent variational theory model in the partial ionization region and create new theoretical models.

  11. Our Favorite Film Shocks

    DEFF Research Database (Denmark)

    Willerslev, Rane; Suhr, Christian

    2014-01-01

    The modern medium of film has long been hailed for its capacity for producing shocks of an entertaining, thought-provoking, or even politically emancipative nature. But what is a shock, how and when does it occur, how long does it last, and are there particular techniques for producing cinematic...

  12. Geometrical shock dynamics for magnetohydrodynamic fast shocks

    KAUST Repository

    Mostert, W.; Pullin, D. I.; Samtaney, Ravi; Wheatley, V.

    2016-01-01

    We describe a formulation of two-dimensional geometrical shock dynamics (GSD) suitable for ideal magnetohydrodynamic (MHD) fast shocks under magnetic fields of general strength and orientation. The resulting area–Mach-number–shock-angle relation is then incorporated into a numerical method using pseudospectral differentiation. The MHD-GSD model is verified by comparison with results from nonlinear finite-volume solution of the complete ideal MHD equations applied to a shock implosion flow in the presence of an oblique and spatially varying magnetic field ahead of the shock. Results from application of the MHD-GSD equations to the stability of fast MHD shocks in two dimensions are presented. It is shown that the time to formation of triple points for both perturbed MHD and gas-dynamic shocks increases as (Formula presented.), where (Formula presented.) is a measure of the initial Mach-number perturbation. Symmetry breaking in the MHD case is demonstrated. In cylindrical converging geometry, in the presence of an azimuthal field produced by a line current, the MHD shock behaves in the mean as in Pullin et al. (Phys. Fluids, vol. 26, 2014, 097103), but suffers a greater relative pressure fluctuation along the shock than the gas-dynamic shock. © 2016 Cambridge University Press

  13. Geometrical shock dynamics for magnetohydrodynamic fast shocks

    KAUST Repository

    Mostert, W.

    2016-12-12

    We describe a formulation of two-dimensional geometrical shock dynamics (GSD) suitable for ideal magnetohydrodynamic (MHD) fast shocks under magnetic fields of general strength and orientation. The resulting area–Mach-number–shock-angle relation is then incorporated into a numerical method using pseudospectral differentiation. The MHD-GSD model is verified by comparison with results from nonlinear finite-volume solution of the complete ideal MHD equations applied to a shock implosion flow in the presence of an oblique and spatially varying magnetic field ahead of the shock. Results from application of the MHD-GSD equations to the stability of fast MHD shocks in two dimensions are presented. It is shown that the time to formation of triple points for both perturbed MHD and gas-dynamic shocks increases as (Formula presented.), where (Formula presented.) is a measure of the initial Mach-number perturbation. Symmetry breaking in the MHD case is demonstrated. In cylindrical converging geometry, in the presence of an azimuthal field produced by a line current, the MHD shock behaves in the mean as in Pullin et al. (Phys. Fluids, vol. 26, 2014, 097103), but suffers a greater relative pressure fluctuation along the shock than the gas-dynamic shock. © 2016 Cambridge University Press

  14. Induction of heat shock-like proteins in Vigna sinensis seedlings growing under ultraviolet-B (280-320 nm) enhanced radiation

    International Nuclear Information System (INIS)

    Nedunchezhian, N.; Annamalainathan, K.; Kulandaivelu, G.

    1992-01-01

    The effect of ultraviolet-B (UV-B) enhanced fluorescent radiation on protein profile and protein synthesis has been investigated in Vigna sinensis L. cv. Walp seedlings growing at various temperatures. In seedlings growing at 30°C, UV-B radiation decreased the level of several proteins as seen in Coomassie brilliant blue stained gel. However, fluorography of the same gel indicates induction of three sets of proteins in the range of 70. 53 and 16 k Da. Such induction under UV-B enhanced radiation resembled that found after heat shock treatments. In seedlings at 10 and 20°C, induction of such proteins varied both qualitatively and quantitatively. At 40°C. UV-B enhanced radiation caused a cumulative effect with temperature. Strong induction of specific proteins by UV-B radiation in seedlings growing under normal temperature indicates a possible protective role

  15. Radiation Dose Assesment And Risk Estimation During Extracorporeal Shock Wave Lithotripsy

    International Nuclear Information System (INIS)

    Sulieman, A.; Ibrahim, A.A.; Osman, H.; Yousef, M.

    2011-01-01

    Extracorporeal shockwave lithotripsy (ESWL) is considered the gold standard for calculi fragmentation. The aims of this study are to measure the entrance surface dose (ESD) using thermo-luminescence dosimeter (TLDs) and to estimate the probability of carcinogenesis during ESWL procedure. The study was carried out at two centers (Group A, 50 patients) and (Group B, 25 patients). The mean ESD and effective doses were 36 mGy and 34 mSv. The results show that the probability of carcinogenesis is a tiny value 100 per million patients) but the main biological effect is occurring due to the accumulative impact of radiation.

  16. Laser absorption, power transfer, and radiation symmetry during the first shock of inertial confinement fusion gas-filled hohlraum experiments

    International Nuclear Information System (INIS)

    Pak, A.; Dewald, E. L.; Landen, O. L.; Milovich, J.; Strozzi, D. J.; Berzak Hopkins, L. F.; Bradley, D. K.; Divol, L.; Ho, D. D.; MacKinnon, A. J.; Meezan, N. B.; Michel, P.; Moody, J. D.; Moore, A. S.; Schneider, M. B.; Town, R. P. J.; Hsing, W. W.; Edwards, M. J.

    2015-01-01

    Temporally resolved measurements of the hohlraum radiation flux asymmetry incident onto a bismuth coated surrogate capsule have been made over the first two nanoseconds of ignition relevant laser pulses. Specifically, we study the P2 asymmetry of the incoming flux as a function of cone fraction, defined as the inner-to-total laser beam power ratio, for a variety of hohlraums with different scales and gas fills. This work was performed to understand the relevance of recent experiments, conducted in new reduced-scale neopentane gas filled hohlraums, to full scale helium filled ignition targets. Experimental measurements, matched by 3D view factor calculations, are used to infer differences in symmetry, relative beam absorption, and cross beam energy transfer (CBET), employing an analytic model. Despite differences in hohlraum dimensions and gas fill, as well as in laser beam pointing and power, we find that laser absorption, CBET, and the cone fraction, at which a symmetric flux is achieved, are similar to within 25% between experiments conducted in the reduced and full scale hohlraums. This work demonstrates a close surrogacy in the dynamics during the first shock between reduced-scale and full scale implosion experiments and is an important step in enabling the increased rate of study for physics associated with inertial confinement fusion

  17. Laser absorption, power transfer, and radiation symmetry during the first shock of inertial confinement fusion gas-filled hohlraum experiments

    Science.gov (United States)

    Pak, A.; Dewald, E. L.; Landen, O. L.; Milovich, J.; Strozzi, D. J.; Berzak Hopkins, L. F.; Bradley, D. K.; Divol, L.; Ho, D. D.; MacKinnon, A. J.; Meezan, N. B.; Michel, P.; Moody, J. D.; Moore, A. S.; Schneider, M. B.; Town, R. P. J.; Hsing, W. W.; Edwards, M. J.

    2015-12-01

    Temporally resolved measurements of the hohlraum radiation flux asymmetry incident onto a bismuth coated surrogate capsule have been made over the first two nanoseconds of ignition relevant laser pulses. Specifically, we study the P2 asymmetry of the incoming flux as a function of cone fraction, defined as the inner-to-total laser beam power ratio, for a variety of hohlraums with different scales and gas fills. This work was performed to understand the relevance of recent experiments, conducted in new reduced-scale neopentane gas filled hohlraums, to full scale helium filled ignition targets. Experimental measurements, matched by 3D view factor calculations, are used to infer differences in symmetry, relative beam absorption, and cross beam energy transfer (CBET), employing an analytic model. Despite differences in hohlraum dimensions and gas fill, as well as in laser beam pointing and power, we find that laser absorption, CBET, and the cone fraction, at which a symmetric flux is achieved, are similar to within 25% between experiments conducted in the reduced and full scale hohlraums. This work demonstrates a close surrogacy in the dynamics during the first shock between reduced-scale and full scale implosion experiments and is an important step in enabling the increased rate of study for physics associated with inertial confinement fusion.

  18. Laser absorption, power transfer, and radiation symmetry during the first shock of inertial confinement fusion gas-filled hohlraum experiments

    Energy Technology Data Exchange (ETDEWEB)

    Pak, A.; Dewald, E. L.; Landen, O. L.; Milovich, J.; Strozzi, D. J.; Berzak Hopkins, L. F.; Bradley, D. K.; Divol, L.; Ho, D. D.; MacKinnon, A. J.; Meezan, N. B.; Michel, P.; Moody, J. D.; Moore, A. S.; Schneider, M. B.; Town, R. P. J.; Hsing, W. W.; Edwards, M. J. [Lawrence Livermore National Laboratory, Livermore, California, 94550 (United States)

    2015-12-15

    Temporally resolved measurements of the hohlraum radiation flux asymmetry incident onto a bismuth coated surrogate capsule have been made over the first two nanoseconds of ignition relevant laser pulses. Specifically, we study the P2 asymmetry of the incoming flux as a function of cone fraction, defined as the inner-to-total laser beam power ratio, for a variety of hohlraums with different scales and gas fills. This work was performed to understand the relevance of recent experiments, conducted in new reduced-scale neopentane gas filled hohlraums, to full scale helium filled ignition targets. Experimental measurements, matched by 3D view factor calculations, are used to infer differences in symmetry, relative beam absorption, and cross beam energy transfer (CBET), employing an analytic model. Despite differences in hohlraum dimensions and gas fill, as well as in laser beam pointing and power, we find that laser absorption, CBET, and the cone fraction, at which a symmetric flux is achieved, are similar to within 25% between experiments conducted in the reduced and full scale hohlraums. This work demonstrates a close surrogacy in the dynamics during the first shock between reduced-scale and full scale implosion experiments and is an important step in enabling the increased rate of study for physics associated with inertial confinement fusion.

  19. Determination of cosmic ray produced radionuclides by means of background radiation counting system, 3

    International Nuclear Information System (INIS)

    1976-01-01

    This is the third report of the progress report series on studies of cosmic ray produced radionuclides by means of low background radiation counting system. In Part I some characteristics of a low beta-gamma coincidence spectrometer are described -- counter system, electronics, background spectra, counting efficiencies -- and studies on radioactive impurities in materials for scientific research are also described. In Part II, suitable solvents for a large scale liquid scintillation counter were examined and best combinations of solvents, solutes and naphthalene are shown. In Part III, miscellaneous topics are reported. (auth.)

  20. Biological effect produced by ionizing radiations on occupational workers in Carlos Andrade Marin Hospital

    International Nuclear Information System (INIS)

    Arias Pullaguari, Ines Yolanda

    2003-01-01

    The objective of this study was to establish the biological effects on occupational workers. In this study, have made a bibliographic review of the changes on skin of 217 professionals; between 21 and 70 years radiologists, X-ray technicians, radioisotope workers, nurses and others, which were exposed to ionizing radiation, in the departments of Diagnosis and Treatment of the Hospital Carlos Andrade Marin of the Quito city. From this universe 133 workers were excluded of the analysis. From the totality of lesions produced on the skin; the depilation constituted 40.18%, hyper pigmentation 19.34%, hypo pigmentation 9 %, capillary fragility 13.39%, erythema 13.39%, alopecia 5.37%. From the totality of lesions produced in blood: the leukopenia constituted 20.23% between all workers. The percentage method was used for statical calculation. A bibliographic update is done and the most relevant clinical aspects are reviewed. (The author)

  1. An ICF system based on Z-pinch radiation produced by an explosive magnetic generator

    International Nuclear Information System (INIS)

    Garanin, S.G.; Ivanovsky, A.V.; Mkhitariyan, L.S.

    2011-01-01

    It is known that a thermonuclear target can be ignited by an implosion accomplished with X-radiation generated by means of laser radiation conversion or by a Z pinch formed by a high-power current pulse. For these purposes laser facility NIF has been constructed in the USA, 'Megajoule' is being constructed in France and there is a project of laser facility UFL in Russia. The project of stationary facility X has been developed in SNL USA to produce a Z pinch capable of generating an x-ray pulse with parameters close to the ignition threshold. There is a great chance, however, that the already tested technologies, including disc explosive magnetic generators (DEMG), systems of current peaking based on electrically exploded foil opening switches and high-voltage switching devices, allow the intriguing problem of the ignition feasibility to be solved and the quickest and cheapest way to accomplish this to be provided. To explore this possibility, the paper will sequentially analyse the ignition conditions. The required parameters of Z pinch X-radiation and the size of the DEMG-based facility to obtain these parameters will be evaluated. Capabilities of the new current sources based on the DEMG and of the devices shaping a current pulse will be presented and compared with those required for the ignition.

  2. Study of thermochemical nonequilibrium flow in the radiative shock layer of the simulated atmosphere of Titan

    International Nuclear Information System (INIS)

    Koffi-Kpante, Kossi

    1996-01-01

    Inviscid flow of the N 2 -CH 4 -Ar gas mixture in thermochemical nonequilibrium has been studied. We have specially modelled the thermal and the chemical processes, such as vibrational excitation, dissociation, ionization and radiation which can occur in the hypersonic flows. Different vibrational models are tested and the effects of kinetic-vibration coupling modeling are studied on the flow-field properties. Therefore, the intensity of spontaneous emission of CN molecule from B 2 Σ + → X 2 Σ + electronic transition of the violet band, where Δν = 0 is computed. So, comparison is made between experimental and numerical results on: 1) The spontaneous emission of CN, 2) the rotational temperature of CN B state and 3) the vibrational temperature of CN B state. Because of the profiles of the measured intensity and the disagreement between numerical results and measurements, especially on the spontaneous emission and in the thermodynamic size, the inviscid flow and the unsteady boundary layer interaction study is made. Last, the thermal and the chemical processes models described in the first part of this thesis are used to compute the inviscid nonequilibrium flow around the Huygens probe. The equations system has been solved with a finite volume method, in with the fluxes have been split with Van-Leer methods. (author) [fr

  3. A model for radio emission from solar coronal shocks

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, G. Q.; Chen, L.; Wu, D. J., E-mail: djwu@pmo.ac.cn [Purple Mountain Observatory, CAS, Nanjing 210008 (China)

    2014-05-01

    Solar coronal shocks are very common phenomena in the solar atmosphere and are believed to be the drivers of solar type II radio bursts. However, the microphysical nature of these emissions is still an open question. This paper proposes that electron cyclotron maser (ECM) emission is responsible for the generation of radiation from the coronal shocks. In the present model, an energetic ion beam accelerated by the shock first excites the Alfvén wave (AW), then the excited AW leads to the formation of a density-depleted duct along the foreshock boundary of the shock. In this density-depleted duct, the energetic electron beam produced via the shock acceleration can effectively excite radio emission by ECM instability. Our results show that this model may potentially be applied to solar type II radio bursts.

  4. A model for radio emission from solar coronal shocks

    International Nuclear Information System (INIS)

    Zhao, G. Q.; Chen, L.; Wu, D. J.

    2014-01-01

    Solar coronal shocks are very common phenomena in the solar atmosphere and are believed to be the drivers of solar type II radio bursts. However, the microphysical nature of these emissions is still an open question. This paper proposes that electron cyclotron maser (ECM) emission is responsible for the generation of radiation from the coronal shocks. In the present model, an energetic ion beam accelerated by the shock first excites the Alfvén wave (AW), then the excited AW leads to the formation of a density-depleted duct along the foreshock boundary of the shock. In this density-depleted duct, the energetic electron beam produced via the shock acceleration can effectively excite radio emission by ECM instability. Our results show that this model may potentially be applied to solar type II radio bursts.

  5. Effects produced by nuclear radiation in powdery milk; Efectos producidos por radiaciones nucleares en leches en polvo

    Energy Technology Data Exchange (ETDEWEB)

    Urena N, F; Reyes G, A [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1999-07-01

    The objective of this work is to determine the chemical effects produced by the gamma rays and beta particles radiations on the powdery milk. This work treats on the Pre-dose analysis, sampling radiating, electron spin resonance, acidity, proteins, aminoacids, lactose, fatty acids, peroxides, as well as its experimental results. (Author)

  6. The role of microbial low-molecular-weight autoregulatory factors (alkylhydroxybenzenes) in resistance of microorganisms to radiation and heat shock

    Science.gov (United States)

    El-Registan, Galina I.; Mulyukin, Andrey L.; Nikolaev, Yuri A.; Stepanenko, Irina Yu.; Kozlova, Alla N.; Martirosova, Elena I.; Shanenko, Elena F.; Strakhovskaya, Marina G.; Revina, Aleksandra A.

    Low-molecular-weight cell-to-cell communication factors are produced by various pro- and eukaryotes and involved in autoregulation of the growth and development of microbial cultures. As for some bacterial and yeast species, these factors were identified as isomers and homologues of alkylhydroxybenzenes (AHB). Depending on the concentration, they participate in controlling the transition to stationary phase, entering the resting state, and stress resistance of vegetative cells to gamma-irradiation, photooxidation (singlet oxygen), and heat shock. Chemical analogues of microbial AHB protected microbial cultures from stressful situations and exerted (1) the stabilizing activity toward macromolecules and (2) the ability to scavenge active oxygen species. The stabilizing effect of AHBs resulted from their complex formation with protected macromolecules due to intermolecular hydrogen bonds, hydrophobic and electrostatic interactions and was demonstrated on models of individual enzymes (trypsin). Particularly, AHBs protected the yeast from the action of (a) active oxygen species formed during gamma-irradiation (500 Gy, 1.96 Gy/s) or (b) singlet oxygen generated in cells photosensitized by chlorin e 6 (10 μg/L). It is important that microbial AHBs were not species-specific and defended cultured microbial and animal cells from the action of organic toxicants. The use of AHBs as protectants and adaptogens is discussed as well as perspectives of further investigations.

  7. PLANETARY EMBRYO BOW SHOCKS AS A MECHANISM FOR CHONDRULE FORMATION

    Energy Technology Data Exchange (ETDEWEB)

    Mann, Christopher R.; Boley, Aaron C. [Department of Physics and Astronomy University of British Columbia Vancouver, BC V6T 1Z1 (Canada); Morris, Melissa A. [Physics Department State University of New York at Cortland Cortland, NY 13045 (United States)

    2016-02-20

    We use radiation hydrodynamics with direct particle integration to explore the feasibility of chondrule formation in planetary embryo bow shocks. The calculations presented here are used to explore the consequences of a Mars-size planetary embryo traveling on a moderately excited orbit through the dusty, early environment of the solar system. The embryo’s eccentric orbit produces a range of supersonic relative velocities between the embryo and the circularly orbiting gas and dust, prompting the formation of bow shocks. Temporary atmospheres around these embryos, which can be created via volatile outgassing and gas capture from the surrounding nebula, can non-trivially affect thermal profiles of solids entering the shock. We explore the thermal environment of solids that traverse the bow shock at different impact radii, the effects that planetoid atmospheres have on shock morphologies, and the stripping efficiency of planetoidal atmospheres in the presence of high relative winds. Simulations are run using adiabatic and radiative conditions, with multiple treatments for the local opacities. Shock speeds of 5, 6, and 7 km s{sup −1} are explored. We find that a high-mass atmosphere and inefficient radiative conditions can produce peak temperatures and cooling rates that are consistent with the constraints set by chondrule furnace studies. For most conditions, the derived cooling rates are potentially too high to be consistent with chondrule formation.

  8. Modification of a scanning electron microscope to produce Smith-Purcell radiation

    International Nuclear Information System (INIS)

    Kapp, Oscar H.; Sun, Yin-e; Kim, Kwang-Je; Crewe, Albert V.

    2004-01-01

    We have modified a scanning electron microscope (SEM) in an attempt to produce a miniature free electron laser that can produce radiation in the far infrared region, which is difficult to obtain otherwise. This device is similar to the instrument studied by the Dartmouth group and functions on the basic principles first described by Smith and Purcell. The electron beam of the SEM is passed over a metal grating and should be capable of producing photons either in the spontaneous emission regime or in the superradiance regime if the electron beam is sufficiently bright. The instrument is capable of being continuously tuned by virtue of the period of the metal grating and the choice of accelerating voltage. The emitted Smith-Purcell photons exit the instrument via a polyethylene window and are detected by an infrared bolometer. Although we have obtained power levels exceeding nanowatts in the spontaneous emission regime, we have thus far not been able to detect a clear example of superradiance

  9. Cellulose gels produced in room temperature ionic liquids by ionizing radiation

    International Nuclear Information System (INIS)

    Kimura, Atsushi; Nagasawa, Naotsugu; Taguchi, Mitsumasa

    2014-01-01

    Cellulose-based gels were produced in room temperature ionic liquids (RTILs) by ionizing radiation. Cellulose was dissolved at the initial concentration of 20 wt% in 1-ethyl-3-methylimidazolium (EMI)-acetate or N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium (DEMA)-formate with a water content of 18 wt%, and irradiated with γ-rays under aerated condition to produce new cellulose gels. The gel fractions of the cellulose gels obtained in EMI-acetate and DEMA-formate at a dose of 10 kGy were 13% and 19%, respectively. The formation of gel fractions was found to depend on the initial concentration of cellulose, water content, and irradiation temperature. The obtained gel readily absorbed water, methanol, ethanol, dichloromethane, N,N-dimethylacetamide, and RTILs. - Highlights: • Cellulose gels were produced in room temperature ionic liquids (RTILs). • Water plays a crucial role in the cross-linking reaction. • Cellulose gels swollen with RTILs show good electronic conductivity (3.0 mS cm −1 )

  10. Wide range scaling laws for radiation driven shock speed, wall albedo and ablation parameters for high-Z materials

    Science.gov (United States)

    Mishra, Gaurav; Ghosh, Karabi; Ray, Aditi; Gupta, N. K.

    2018-06-01

    Radiation hydrodynamic (RHD) simulations for four different potential high-Z hohlraum materials, namely Tungsten (W), Gold (Au), Lead (Pb), and Uranium (U) are performed in order to investigate their performance with respect to x-ray absorption, re-emission and ablation properties, when irradiated by constant temperature drives. A universal functional form is derived for estimating time dependent wall albedo for high-Z materials. Among the high-Z materials studied, it is observed that for a fixed simulation time the albedo is maximum for Au below 250 eV, whereas it is maximum for U above 250 eV. New scaling laws for shock speed vs drive temperature, applicable over a wide temperature range of 100 eV to 500 eV, are proposed based on the physics of x-ray driven stationary ablation. The resulting scaling relation for a reference material Aluminium (Al), shows good agreement with that of Kauffman's power law for temperatures ranging from 100 eV to 275 eV. New scaling relations are also obtained for temperature dependent mass ablation rate and ablation pressure, through RHD simulation. Finally, our study reveals that for temperatures above 250 eV, U serves as a better hohlraum material since it offers maximum re-emission for x-rays along with comparable mass ablation rate. Nevertheless, traditional choice, Au works well for temperatures below 250 eV. Besides inertial confinement fusion (ICF), the new scaling relations may find its application in view-factor codes, which generally ignore atomic physics calculations of opacities and emissivities, details of laser-plasma interaction and hydrodynamic motions.

  11. Effect of γ-rays radiation pretreatment on enzymatic hydrolysis of corn straw for producing sugar

    International Nuclear Information System (INIS)

    Tang Hongtao; Ha Yiming; Wang Feng

    2011-01-01

    The effect of γ-rays radiation pretreatment on enzymatic of corn straw for producing sugar was studied. The relationship between irradiation-dosage and content of reducing sugar was investigated in DNS method. After 1000 kGy irradiation, the content of reducing sugar reached about 317.35%. A synergistic effect between irradiation and enzyme was observed. The reducing sugar yield after enzymatic hydrolysis reached 20.51% when the corn straw powder (0.15 mm) irradiated with a dose of 1000 kGy. The result shows that the irradiation had significant influence on enzymatic hydrolysis of corn straw. At the 500 kGy pre-irradiation, compared with initial yield, the maximum sugar yield of sample had increased by 13.68% while the irradiated corn straw stored in 20 days. (authors)

  12. Use of gamma radiation to control fusarium verticilloides producing two known mycotoxins in infected corn grains

    International Nuclear Information System (INIS)

    Youssef, K.A.; Abouzeid, M.A.; Hassan, A.A.; Abd-Elrahman, D.G.; Hammad, A.A.

    2007-01-01

    Fusarium verticillioides Sacc. (Nirenberg) was isolated from fresh grains collected from corn fields with ears symptoms. When cultured in liquid media under controlled incubation conditions, two already known mycotoxins were produced. The two mycotoxins were obtained through the extraction process of the lyophilized culture filtrate under acidic condition using ethyl acetate and were detected by thin layer chromatography and high performance liquid chromatography in comparison with the authentic of both acids. Mass spectroscopic investigations confirmed the molecular weight of the two toxic compounds which are known as fusaric and 9, 10-dehydro fusaric acids. Application of gamma radiation at doses up to 3 KGy caused a slight decrease in the mould count of isolated pathogen while a 5 KGy dose caused a dramatic reduction in fungal count and at irradiation dose of 12.5 KGy the fungus was completely inhibited for up to 12 weeks of storage

  13. Spectral and spatial shaping of a laser-produced ion beam for radiation-biology experiments

    Directory of Open Access Journals (Sweden)

    L. Pommarel

    2017-03-01

    Full Text Available The study of radiation biology on laser-based accelerators is most interesting due to the unique irradiation conditions they can produce, in terms of peak current and duration of the irradiation. In this paper we present the implementation of a beam transport system to transport and shape the proton beam generated by laser-target interaction for in vitro irradiation of biological samples. A set of four permanent magnet quadrupoles is used to transport and focus the beam, efficiently shaping the spectrum and providing a large and relatively uniform irradiation surface. Real time, absolutely calibrated, dosimetry is installed on the beam line, to enable shot-to-shot control of dose deposition in the irradiated volume. Preliminary results of cell sample irradiation are presented to validate the robustness of the full system.

  14. Influence of NORMs on the natural background radiation level in petroleum-producing countries

    International Nuclear Information System (INIS)

    Ali, F.M.

    2002-01-01

    Naturally occurring radioactive materials (NORMs) which are found in the Earth's crust, in the form of 226 Ra and 228 Ra and their associated radionuclides, are brought to the surface of the ground as a result of oil production processes, and are known under the name of technologically enhanced natural radioactivity (TENR). These represent a potential hazard of significant scale. 226 Ra, an α emitter, represents a potential internal radiation exposure hazard to both workers and members of the public, arising from the inhalation and ingestion of the dust produced during cleaning operations for the descaling of pipes and separator tanks. In addition to this, a higher than normal background γ exposure rate is to be observed both around and directly at the areas where the mud from the separator tanks and pipe cleaning operations was routinely dumped. Therefore, the aim of this work was to present the data on radiation levels measured in contaminated areas located near to a number of oilfields in Egypt and in Syria. The decontamination processes undertaken and the precautions necessary to ensure elimination of the possible transport mechanisms for contaminated dust into public areas by wind are presented. (orig.)

  15. Gamma-radiation produces abnormal Bergmann fibers and ectopic granule cells in mouse cerebellar cortex

    International Nuclear Information System (INIS)

    Inouye, Minoru; Hayasaka, Shizu; Funahashi, Atsushi; Yamamura, Hideki

    1992-01-01

    Morphological changes in Bergmann glial fibers in the developing cerebellar cortex produced by exposure to gamma-rays were investigated in association with ectopic granule cells. Six-day-old mice that had been exposed to 3 Gy of gamma-radiation were killed 6 hours after exposure or at 7 through 30 days of age. Their cerebella were examined histologically and immunohistochemically for glial fibrillary acidic protein in Bergmann fibers. Extensive cell death took place in the external granular layer (EGL) of the cerebellum from 6 through 24 hours after exposure. This led to the thinning of the EGL and a decrease in the number of migrating cells in the molecular layer. The number of Bergmann cells was not decreased, but the fibers in the molecular layer were distorted; whereas, in the control these fibers were straight and perpendicular to the pial surface. The EGL began to recover 2 days after exposure, and abnormally oriented migrating cells were seen. At 17 days of age, some cell clustering was observed in the molecular layer of the irradiated cerebellum. Distortion of the Bergmann fibers was marked in regions where ectopic granule cells appeared at 30 days of age. These findings suggest that the distortion of Bergmann fibers leads to the production of ectopic granule cells after exposure to gamma-radiation. (author)

  16. Effects of Long-Term Exposure to 60 GHz Millimeter-Wavelength Radiation on the Genotoxicity and Heat Shock Protein (Hsp Expression of Cells Derived from Human Eye

    Directory of Open Access Journals (Sweden)

    Shin Koyama

    2016-08-01

    Full Text Available Human corneal epithelial (HCE-T and human lens epithelial (SRA01/04 cells derived from the human eye were exposed to 60 gigahertz (GHz millimeter-wavelength radiation for 24 h. There was no statistically significant increase in the micronucleus (MN frequency in cells exposed to 60 GHz millimeter-wavelength radiation at 1 mW/cm2 compared with sham-exposed controls and incubator controls. The MN frequency of cells treated with bleomycin for 1 h provided positive controls. The comet assay, used to detect DNA strand breaks, and heat shock protein (Hsp expression also showed no statistically significant effects of exposure. These results indicate that exposure to millimeter-wavelength radiation has no effect on genotoxicity in human eye cells.

  17. Radiation-produced electron migration along 5-bromouracil-substituted DNA in cells and in solutions

    International Nuclear Information System (INIS)

    Beach, C.M.

    1981-01-01

    Results of work by other investigators support the theory of charge migration in DNA. Charge transfer between nucleotides and electron and energy migration in solid state DNA have been detected, but no previous experiments have demonstrated charge migration in aqueous solutions of DNA or in DNA inside an E. coli cell. Such experiments were performed by substituting different amounts of 5-bromouracil (BU) for thymine in E. coli DNA and assaying for the amount of bromide given off from the reaction of bromouracil with hydrated electrons produced by ionizing radiation to form uracil-5-yl radicals and free bromide. By varying the amount of BU incorporated in the DNA, the average distance between the BU bases was varied, and because the number of BU/electron reactions was monitored by the amount of bromide released, the maximum average electron migration distance along the BU-DNA was estimated. Charge migration was demonstrated, and the maximum average electron migration distance in aqueous solutions of BU-DNA was measured to be 8 to 10 base distances (assuming only intrastrand migration). Only 11 to 16% of the electrons produced attacked BU-DNA in aqueous solution, and only 1% resulted in bromide release from BU-DNA inside E. coli. Charge migration was demonstrated in BU-DNA inside E. coli, and the maximum average migration distance was measured to be 5 to 6 base distances

  18. Thermo tolerant and ethanol producing saccharomyces cerevisiae mutants using gamma radiation

    International Nuclear Information System (INIS)

    Karima, H.M.; Ismail, A.A.; El-Batal, A.I.

    1997-01-01

    Gene manipulation now plays the main role in fermentation industries. However, throughout ethanol production processes, it appeared the requirements for the selection of higher-producing isolate(s) associated, at the same time, with heat-resistant to overcome higher degrees above 30-35 degree, a step which, actually, will reduce final - producing costs. A total of 43 yeast isolates were selected, after exposure of the strain saccharomyces cervisiae to different doses of gamma radiation. Isolated varied in colony size from the original strain as well as among themselves. These isolates were screened for their ability to grow on glucose and supplemented cane molasses media at 30 degree and 40 degree. Out fo them, only 13 isolates proved to grow well on 40 degree. Furthermore, determination of ethanol production by each of these mutants revealed that yielded in general, 16 to 52.0% increase in alcohol production at 40 degree on cane molasses medium (17.5% w/v initial sugars), compared to the original strain. At 40 degree, maximum ethanol yield was 0.63 coupled with 9.5% ethanol concentration and 85.1% sugar conversion which represents 40, 46.2 and 3.4% increase, respectively from the parental strain

  19. High oleic acid content materials of rapeseed (Brassica napus) produced by radiation breeding

    International Nuclear Information System (INIS)

    Guan Chunyun; Liu Chunlin; Chen Sheyuan

    2006-01-01

    High oleic acid content rapeseed breeding has great significance, because high oleic acid oil is a healthy and nutritious oil, which is of a long shelflife and also propitious to producing biodiesel fuel. The high oleic acid content breeding materials of rapeseed (B. napus) were obtained by 80-100 kR ~(60)Co gamma ray ionizing radiation treatment of dry seeds and continuous selection. The results showed that the oleic acid contents of M (2), M (3) and M (4) progenies increased by different grades. Moreover, the oleic acid content of M (5) progeny increased greatly. The oleic acid contents were higher than 70% in the most of the plants and the highest one reached 93.5 %. The base G was transited by base A in fad (2) gene at the 270 site of high oleic acid mutation (M(6) 04-855). The location is at the beta folding area and conservative area of this protein. Base mutation at sites 1 044 and 1 062 also led to produce a stop condon. These changes in structure led to loss the function of fad (2). According to molecular mechanism of gene mutation, no matter what transvertion or transition happens, several replications are needed. That is to say several generations are needed. That was also the reason why high oleic acid content mutation occurred in later generations

  20. Chemical effects produced by the ionizing radiation in the mercury beating heart reaction

    International Nuclear Information System (INIS)

    Castillo-Rojas, S.; Burillo, G.; Gonzalez-Chavez, J.L.; Vicente, L.

    2002-01-01

    Complete text of publication follows. In a recent paper we have shown the existence of complex modes of oscillation in the study of the extinction dynamics of the mercury beating heart reaction. It was proposed that one of the species responsible for the oscillatory movements of this reaction is the mercury(I), in anyone in their forms, either free or molecular. the formation of Hg 2 2+ from γ irradiation of 60 Co to the system Hg 0 /H 2 SO 4 (6M) allowed to elucidate the probable mechanism of reaction. The objective of this work is to study how the ionizing radiation affects the dynamics of extinction of this reaction, which is related with the existence of certain chemical species. The study was carried out in 2 ways: a) Method I: H 2 SO 4 (6M) was first irradiated and to the irradiated solution the Hg 0 was added and b) Method II: the system Hg 0 /H 2 SO 4 (6M) was irradiated. The different irradiated systems were put into reaction with Fe 0 to investigate if there were differences between the two irradiated systems and how the complex modes of oscillation of the reaction were affected. The quantity of Hg 2 2+ produced by method I is bigger than in method II. This is explained because the majority species produced by radiolysis of H 2 SO 4 are sulfate radical and H 2 O 2 that act as oxidizer agents and their potential values allow to suppose that these substances react with Hg 0 to produce Hg 2 2+ . On the other hand, by method II mercury clusters (Hg 4 3+ ) are formed as was reported by Sukhov and Ershov in pulse radiolysis of aqueous Hg 2 2+ solutions. We assume that the formation of these mercury clusters has to be observed with the decrease of the Hg 2 2+ concentration when one makes the radiolysis by method II. In general, the preliminary studies allow establishing that the ionizing radiation does not affect the extinction dynamics but it increases the half-life of this reaction

  1. Radiation-produced electron migration along 5-bromouracil-substituted DNA in cells and in solutions

    International Nuclear Information System (INIS)

    Beach, C.M.

    1981-01-01

    Results of work by other investigators support the theory of charge migration in DNA. Charge transfer between nucleotides and electron and energy migration in solid state DNA have been detected, but no previous experiments have demonstrated charge migration in aqueous solutions of DNA or in DNA inside an E. coli cell. Such experiments were performed by substituting different amounts of 5-bromouracil (BU) for thymine in E. coli DNA and assaying for the amount of bromide given off from the reaction of bromouracil with hydrated electrons produced by ionizing radiation to form uracil-5-yl radicals and free bromide. By varying the amount of BU incorporated in the DNA, the average distance between the BU bases was varied, and because the number of BU/electron reactions was monitored by the amount of bromide released, the maximum average electron migration distance along the BU-DNA was estimated. Hydrated electrons, e/sub aq/, were shown to react with BU in BU-DNA with the resultant release of bromide with G(-BR - ) = 0.519 +- 0.062. OH radicals were half as reactive as e/sub aq/ toward producing bromide from BU-DNA. O 2 , which has been shown to transfer charge to BU in aqueous solution, did not transfer charge to BU-DNA. The CO 2 radical was shown to cause the release of bromide from BU-DNA at least as effectively as e/sub aq/. Charge migration was demonstrated, and the maximum average electron migration distance in aqueous solutions of BU-DNA was measured to be 8 to 10 base distances (assuming only intrastrand migration). Only 11% to 16% of the electrons produced attacked BU-DNA in aqueous solution, and only 1% resulted in bromide release from BU-DNA inside E. coli. Charge migration was demonstrated in BU-DNA inside E. coli., and the maximum average migration distance was measured to be 5 to 6 base distances

  2. Shock Prevention

    Science.gov (United States)

    1978-01-01

    The electrician pictured is installing a General Electric Ground Fault Interrupter (GFI), a device which provides protection against electrical shock in the home or in industrial facilities. Shocks due to defective wiring in home appliances or other electrical equipment can cause severe burns, even death. As a result, the National Electrical Code now requires GFIs in all new homes constructed. This particular type of GFI employs a sensing element which derives from technology acquired in space projects by SCI Systems, Inc., Huntsville, Alabama, producer of sensors for GE and other manufacturers of GFI equipment. The sensor is based on the company's experience in developing miniaturized circuitry for space telemetry and other spacecraft electrical systems; this experience enabled SCI to package interruptor circuitry in the extremely limited space available and to produce sensory devices at practicable cost. The tiny sensor measures the strength of the electrical current and detects current differentials that indicate a fault in the functioning of an electrical system. The sensing element then triggers a signal to a disconnect mechanism in the GFI, which cuts off the current in the faulty circuit.

  3. In vivo effects of UV radiation on multiple endpoints and expression profiles of DNA repair and heat shock protein (Hsp) genes in the cycloid copepod Paracyclopina nana

    Energy Technology Data Exchange (ETDEWEB)

    Won, Eun-Ji; Han, Jeonghoon [Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Lee, Yeonjung; Kumar, K. Suresh; Shin, Kyung-Hoon [Department of Marine Sciences and Convergent Technology, College of Science and Technology, Hanyang University, Ansan 426-791 (Korea, Republic of); Lee, Su-Jae [Department of Life Sciences, College of Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of); Park, Heum Gi, E-mail: hgpark@gwnu.ac.kr [Department of Marine Resource Development, College of Life Sciences, Gangneung-Wonju National University, Gangneung 210-702 (Korea, Republic of); Lee, Jae-Seong, E-mail: jslee2@skku.edu [Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2015-08-15

    Highlights: • UV-B radiation induced a significant reduction of the re-brooding rate of ovigerous females. • A dose-dependent decrease in food ingestion and the rate of assimilation to the body upon UV radiation. • Expression of base excision repair-associated and hsp chaperoning genes was significantly increased upon UV radiation in P. nana. - Abstract: To evaluate the effects of ultraviolet (UV) radiation on energy acquisition and consumption, the copepod Paracyclopina nana was irradiated with several doses (0–3 kJ/m{sup 2}) of UV. After UV radiation, we measured the re-brooding success, growth pattern of newly hatched nauplii, ingestion rate, and assimilation of diet. In addition, we checked the modulated patterns of DNA repair and heat shock protein (hsp) chaperoning genes of P. nana. UV-B radiation induced a significant reduction (7–87%) of the re-brooding rate of ovigerous females, indicating that UV-induced egg sac damage is closely correlated with a reduction in the hatching rate of UV-irradiated ovigerous female offspring. Using chlorophyll a and stable carbon isotope incubation experiments, we found a dose-dependent decrease (P < 0.05) in food ingestion and the rate of assimilation to the body in response to UV radiation, implying that P. nana has an underlying ability to shift its balanced-energy status from growth and reproduction to DNA repair and adaptation. Also, expression of P. nana base excision repair (BER)-associated genes and hsp chaperoning genes was significantly increased in response to UV radiation in P. nana. These findings indicate that even 1 kJ/m{sup 2} of UV radiation induces a reduction in reproduction and growth patterns, alters the physiological balance and inhibits the ability to cope with UV-induced damage in P. nana.

  4. In vivo effects of UV radiation on multiple endpoints and expression profiles of DNA repair and heat shock protein (Hsp) genes in the cycloid copepod Paracyclopina nana

    International Nuclear Information System (INIS)

    Won, Eun-Ji; Han, Jeonghoon; Lee, Yeonjung; Kumar, K. Suresh; Shin, Kyung-Hoon; Lee, Su-Jae; Park, Heum Gi; Lee, Jae-Seong

    2015-01-01

    Highlights: • UV-B radiation induced a significant reduction of the re-brooding rate of ovigerous females. • A dose-dependent decrease in food ingestion and the rate of assimilation to the body upon UV radiation. • Expression of base excision repair-associated and hsp chaperoning genes was significantly increased upon UV radiation in P. nana. - Abstract: To evaluate the effects of ultraviolet (UV) radiation on energy acquisition and consumption, the copepod Paracyclopina nana was irradiated with several doses (0–3 kJ/m 2 ) of UV. After UV radiation, we measured the re-brooding success, growth pattern of newly hatched nauplii, ingestion rate, and assimilation of diet. In addition, we checked the modulated patterns of DNA repair and heat shock protein (hsp) chaperoning genes of P. nana. UV-B radiation induced a significant reduction (7–87%) of the re-brooding rate of ovigerous females, indicating that UV-induced egg sac damage is closely correlated with a reduction in the hatching rate of UV-irradiated ovigerous female offspring. Using chlorophyll a and stable carbon isotope incubation experiments, we found a dose-dependent decrease (P < 0.05) in food ingestion and the rate of assimilation to the body in response to UV radiation, implying that P. nana has an underlying ability to shift its balanced-energy status from growth and reproduction to DNA repair and adaptation. Also, expression of P. nana base excision repair (BER)-associated genes and hsp chaperoning genes was significantly increased in response to UV radiation in P. nana. These findings indicate that even 1 kJ/m 2 of UV radiation induces a reduction in reproduction and growth patterns, alters the physiological balance and inhibits the ability to cope with UV-induced damage in P. nana

  5. Measurement and Prediction of Radiative Non-Equilibrium for Air Shocks Between 7-9 km/s

    Science.gov (United States)

    Cruden, Brett A.; Brandis, Aaron M.

    2017-01-01

    The present paper describes a recent characterization of thermochemical non-equilibrium for shock speeds between 7 and 9 km/s in the NASA Ames Electric Arc Shock Tube (EAST) Facility. Data are spectrally resolved from 190-1450 nm and spatially resolved behind the shock front. The data are analyzed in terms of a spectral non-equilibrium metric, defined as the average radiance within +/- 2 cm of the peak. Simulations with DPLR/NEQAIR using different rate chemistries show these conditions to be poorly replicated. The sources of discrepancy are examined, leading to an update to the NEQAIR non-Boltzmann model and DPLR rate chemistry. New parameters for the rate chemistry and non-Boltzmann modeling are reported.

  6. Investigation the structural and functional changes of heart in elderly soldiers who was working with radiation producing equipments

    International Nuclear Information System (INIS)

    Li Jiahua; Li Li; Cao Hongliu; Wang Quanhong; Huang Fang

    2010-01-01

    Objective: To investigate the structural and functional changes of heart in elderly soldiers who was working with radiation producing equipments. The involvement of cardiovascular system in radiation and its intensity was investigated in this study. Methods: Fifty elderly males (>60 years old) who were exposed to radiation producing equipments (exposure group) and 50 elderly (>60 years old) retired male commanders without radiation exposure history (control group) were enrolled in this study. Echocardiographic evaluation of cardiac structure and function was conducted with Siemens Sonline G60 ultrasound system. 12-lead electrocardiogram (ECG) and routine physical examination had also been done in both groups. Results: Ejection fraction, minor axis reduced rate had no distinct difference between exposure group and control group (t=1.52 and t=1.68, P>0.05). Cardiac output, cardiac stroke volume, stroke index, ventricular diastolic flow velocity E/A ratios in exposure group were lower than control group (t=11.81, t=7.11 and t=7.88, P 2 =9.72, and χ 2 =5.19, P<0.05). Conclusion: Chronic low dose radiation may have effects on the cardiovascular sys-tem, so dynamic monitoring of changes in cardiac structure and function is worth on the safety and health for persons who may exposure to radiation and help to prevent early and long-term effects of radiation. (authors)

  7. The processing of intravenous coronary angiography angiograms produced by synchrotron radiation. Ch. 20B

    International Nuclear Information System (INIS)

    Zeman, H.D.

    1991-01-01

    Intravenous coronary angiography using synchrotron radiation (SR) has been demonstrated in recent years to hold promise for performing diagnostic examinations of human patients less invasively than the presently required arterially invasive procedures. The high intensity and tunability of SR, the linearity and large dynamic range of multi-channel Si(Li) detectors, and the scatter reducing properties of a fan-beam geometry should eventually lead to intravenous images of the human heart of a quality equal to that already achieved in dogs. However, two major problems with the intravenous angiography technique remain. Contrast material in the cardiac chambers and great vessels obscures the coronary arteries overlying these structures. In addition, the contrast material in the capillary bed of the heart muscle produces a gray haze that limits the extent to which contrast enhancement can be used to bring out details in the coronary arteries without turning this haze into a black cloud. For these reasons, an image processing technique is necessary which can remove large smooth opaque structures from the angiogram, allowing the fine detail overlying them to be made visible, and allowing contrast enhancement of this detail to be performed. This chapter discusses the image processing technique and illustrates this technique by some experimental results. (author). 13 refs.; 15 figs

  8. Parametric instability producing broad symmetrical structure in the spectrum of ionospheric heating-induced radiation

    International Nuclear Information System (INIS)

    Kuo, S.P.

    1997-01-01

    A four-wave interaction process in which an O-mode electromagnetic pump decays parametrically into a lower hybrid decay mode and two-electron Bernstein sidebands is analyzed. It is shown that the instability can be excited in a spatial region near the electron Bernstein/upper hybrid double resonance and in a narrow pump frequency range slightly below the third harmonic electron cyclotron resonance. The two electron Bernstein sidebands have about the same intensity and thus, produce Broad Symmetrical Structure (BSS) in the emission spectrum after being converted into electromagnetic radiation by scattering off background field-aligned density irregularities. The results also show that the size of the instability zone becomes very small as the pump frequency operates near a cyclotron harmonic higher than the third. Thus, the converted emission will be too weak to be detected. This explains why the BSS feature in the spectrum of stimulated electromagnetic emissions (SEEs) has only been observed in the third harmonic case. copyright 1997 American Institute of Physics

  9. Online detection of radiation produced in Boron-10 neutron capture reaction: preliminary studies

    International Nuclear Information System (INIS)

    Portu, A.; Galván, V.; González, S.J.; Thorp, S.; Santa Cruz, G.; Saint Martin, G.; Blostein, J.J.

    2013-01-01

    Boron microdistribution in both tumor and normal tissue sections can be studied by the autoradiography technique in solid state nuclear track detectors (SSNTD). A measurement of boron concentration in tissue is obtained through the evaluation of the density of tracks produced by alpha and lithium ions generated in the neutron capture reaction 10B(n,α) 7 Li. This knowledge is pivotal when a BNCT (Boron Neutron Capture Therapy) protocol is considered. A new methodology is proposed in order to record alpha and lithium events in real time, as light spots superimposed to the tissue section image. CCD (Charge-Coupled Device) and CMOS (Complementary Metal Oxide Semiconductor) are used as detectors, with the advantage of avoiding the superposition of events. Commercial web cams were employed for the preliminary experiments. They were partially disassembled in order to get the sensor chip uncovered. These devices were exposed to different radiation sources: 6.118 MeV alpha particles (252Cf), 0.662 MeV gamma rays ( 137 Cs) and thermal neutrons (moderated 241 Am-Be source, 103n.cm2.seg-1), to analyze the characteristics of the respective images. Pictures from tissue sections put in contact with the sensor surface were also acquired. A software was developed in Matlab to perform the image capture and processing. Early results show the feasibility of using these devices to study the distribution 10B in tissue samples. (author)

  10. Application of Gamma Radiation on Bio-oil Produced from Pyrolysis of Soybean Cake

    International Nuclear Information System (INIS)

    Pichestapong, P.; Injarean, U.; Prapakornrattana, P.; Charoen, K.

    2014-01-01

    Soybean cake residue from soy milk making can be pyrolysed to produce pyrolysis liquid or bio-oil which has potency to be used as liquid fuel. Pyrolysis of soybean cake residue with the application of gamma irradiation was investigated in a batch reactor at 450°C for 1.5 hr under nitrogen flow 250 cc/min. Feed of soybean cake residue was exposed to gamma radiation at the doses of 200 to 1,000 kGy before pyrolysing. It was found that pyrolysis liquid yield increased significantly by 12.9 to 19.3 % at the irradiation doses of 400 kGy and higher. The increment was mainly due to the increasing of aqueous phase in the pyrolysis liquid. The heating value of organic phase in the pyrolysis liquid was 7,890 kcal/kg. The organic phase from the unexposed feed was also irradiated at 20-100 kGy. The viscosity of irradiated organic phase was found to increase with the increasing irradiation dose. Irradiated organic phase was distilled at temperatures 200 and 250°C. It was found that the first distilled fraction (<200°C) corresponding to gasoline fraction increased with the increasing irradiation dose while the second distilled fraction (200-250°C) corresponding to kerosene fraction seems to decrease. The composition of organic phase was also determined by GC-MS.

  11. Transformation of solar radiation in Norway spruce stands into produced biomass - the effect of stand density

    International Nuclear Information System (INIS)

    Marková, I.; Marek, M.V.; Pokorný, R.

    2011-01-01

    The present paper is focused on the assessment of the effects of stand density and leaf area development on radiation use efficiency in the mountain cultivated Norway spruce stand. The young even-aged (17-years-old in 1998) plantation of Norway spruce was divided into two experimental plots differing in their stand density in 1995. During the late spring of 2001 next cultivating high-type of thinning of 15% intensity in a reduction of stocking density was performed. The PAR regime of investigated stands was continually measured since 1992. Total aboveground biomass (TBa) and TBa increment were obtained on the basis of stand inventory. The dynamic of LAI development showed a tendency to be saturated, i.e. the LAI value close to 11 seems to be maximal for the local conditions of the investigated mountain cultivated Norway spruce stand in the Beskids Mts. Remarkable stimuli (up to 17%) of LAI formation were started in 2002, i.e. as an immediate response to thinning. Thus, the positive effect of thinning on LAI increase was confirmed. The data set of absorbed PAR and produced TBa in the period 1998-2003 was processed by the linear regression of Monteith's model, which provided the values of the coefficient of solar energy conversion efficiency into biomass formation. The differences in biomass formation values between the dense and sparse plot after thinning amounted to 18%

  12. Shock Dynamics in Stellar Outbursts. I. Shock Formation

    Energy Technology Data Exchange (ETDEWEB)

    Ro, Stephen; Matzner, Christopher D., E-mail: ro@astro.utoronto.ca [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada)

    2017-05-20

    Wave-driven outflows and non-disruptive explosions have been implicated in pre-supernova outbursts, supernova impostors, luminous blue variable eruptions, and some narrow-line and superluminous supernovae. To model these events, we investigate the dynamics of stars set in motion by strong acoustic pulses and wave trains, focusing on nonlinear wave propagation, shock formation, and an early phase of the development of a weak shock. We identify the shock formation radius, showing that a heuristic estimate based on crossing characteristics matches an exact expansion around the wave front and verifying both with numerical experiments. Our general analytical condition for shock formation applies to one-dimensional motions within any static environment, including both eruptions and implosions. We also consider the early phase of shock energy dissipation. We find that waves of super-Eddington acoustic luminosity always create shocks, rather than damping by radiative diffusion. Therefore, shock formation is integral to super-Eddington outbursts.

  13. Radiation damage produced by swift heavy ions in rare earth phosphates

    Energy Technology Data Exchange (ETDEWEB)

    Romanenko, Anton

    2017-02-13

    This work is devoted to the study of radiation damage produced by swift heavy ions in rare earth phosphates, materials that are considered as perspective for radioactive waste storage. Single crystals of rare earth phosphates were exposed to 2.1 GeV gold (Au) and 1.5 GeV xenon (Xe) ions of and analyzed mainly by Raman spectroscopy. All phosphates were found almost completely amorphous after the irradiation by 2.1 GeV Au ions at a fluence of 1 x 10{sup 13} ions/cm{sup 2}. Radiation-induced changes in the Raman spectra include the intensity decrease of all Raman bands accompanied by the appearance of broad humps and a reduction of the pronounced luminescence present in virgin samples. Analyzing the Raman peak intensities as a function of irradiation fluence allowed the calculation of the track radii for 2.1 GeV Au ions in several rare earth phosphates, which appear to be about 5.0 nm for all studied samples. Series of samples were studied to search for a trend of the track radius depending on the rare earth element (REE) cation. Among the monoclinic phosphates both Raman and small-angle X-ray scattering (SAXS) suggest no significant change of the track radius with increasing REE mass. In contrast, within the tetragonal phosphates Raman spectroscopy data suggests a possible slight decreasing trend of the track radius with the increase of REE atomic number. That finding, however, requires further investigation due to the low reliability of the qualitative Raman analysis. Detailed analysis of Raman spectra in HoPO{sub 4} showed the increase of peak width at the initial stage of the irradiation and subsequent decrease to a steady value at higher fluences. This observation suggested the existence of a defect halo around the amorphous tracks in HoPO{sub 4}. Raman peaks were found to initially shift to lower wavenumbers with reversing this trend at the fluence of 5 x 10{sup 11} for NdPO{sub 4} and 1 x 10{sup 12} ions/cm{sup 2} for HoPO{sub 4}. At the next fluence steps

  14. Radiation damage produced by swift heavy ions in rare earth phosphates

    International Nuclear Information System (INIS)

    Romanenko, Anton

    2017-01-01

    This work is devoted to the study of radiation damage produced by swift heavy ions in rare earth phosphates, materials that are considered as perspective for radioactive waste storage. Single crystals of rare earth phosphates were exposed to 2.1 GeV gold (Au) and 1.5 GeV xenon (Xe) ions of and analyzed mainly by Raman spectroscopy. All phosphates were found almost completely amorphous after the irradiation by 2.1 GeV Au ions at a fluence of 1 x 10 13 ions/cm 2 . Radiation-induced changes in the Raman spectra include the intensity decrease of all Raman bands accompanied by the appearance of broad humps and a reduction of the pronounced luminescence present in virgin samples. Analyzing the Raman peak intensities as a function of irradiation fluence allowed the calculation of the track radii for 2.1 GeV Au ions in several rare earth phosphates, which appear to be about 5.0 nm for all studied samples. Series of samples were studied to search for a trend of the track radius depending on the rare earth element (REE) cation. Among the monoclinic phosphates both Raman and small-angle X-ray scattering (SAXS) suggest no significant change of the track radius with increasing REE mass. In contrast, within the tetragonal phosphates Raman spectroscopy data suggests a possible slight decreasing trend of the track radius with the increase of REE atomic number. That finding, however, requires further investigation due to the low reliability of the qualitative Raman analysis. Detailed analysis of Raman spectra in HoPO 4 showed the increase of peak width at the initial stage of the irradiation and subsequent decrease to a steady value at higher fluences. This observation suggested the existence of a defect halo around the amorphous tracks in HoPO 4 . Raman peaks were found to initially shift to lower wavenumbers with reversing this trend at the fluence of 5 x 10 11 for NdPO 4 and 1 x 10 12 ions/cm 2 for HoPO 4 . At the next fluence steps peaks moved in the other direction, passed

  15. Optical studies of defects produced by radiation in LiF:Mg

    International Nuclear Information System (INIS)

    Ranieri, Izilda Marcia

    1979-01-01

    Lithium fluoride crystals doped with magnesium were grown from the melt by the Czochralski's method. Using the fact that the presence of Mg enhances the production of F and M color centers, the relative concentration of Mg was determined by a method devised in this work, This method utilizes the optical density of color centers in irradiated samples where the dose rate is proportional to the rate of formation of these centers. The dynamical equilibrium between F and M centers was studies after X-Rays radiation damage. Thermal treatments at 1000 K and quenches to 77 K, previously to the irradiation, showed that one can dissociate impurity aggregates formed when the crystal was grown. This dissociation implies in a decrease of the formation rate of F and M centers. It was found that isolated Mg impurities trap F centers to form Z centers. In the aggregate form, Mg impurities trap interstitial ions that are produced by the irradiation and that are the anti-centers of the F center. By this mechanism F and its anti-centers are thermally stabilized. It was observed that stoking the crystals at room temperature and well protected from the light show an increase in the M center production with a corresponding decrease in the F center production. This is because periods such as 20 hours are enough to perturb the thermodynamical equilibrium between F and M centers obtained just after the irradiation. To determine the stability of these color centers under light of different wavelengths, optical exposures were used. It was found that M center band is stable under its own wavelength's irradiation at room temperature and does not show dichroism. It was determined that the rate of formation of F and M centers at 343 and 403 K, follows the same behavior at room temperature. An Arrhenius study was made to determine the activation energies of these processes and produced 0,12 eV and 0,24 eV for the F and M centers respectively. Studies of fluorescence were also made after X and t

  16. Study on liquid composition produced by radiation degradiation of N,N-diethylhydroxylamine

    International Nuclear Information System (INIS)

    Wang Jinhua; Bao Borong; Wu Minghong

    2006-01-01

    With the development of nuclear energy, more attention has been paid on reprocessing of the spent fuel. PUREX process is the most established process for large scale reprocessing of spent fuel. In this process, Pu is separated from U by selective reducing Pu(IV). Fe(NH 2 SO 3 ) 2 and U(IV)-NH 2 NH 2 are the two common used reducing agent, the principal advantage of them is that they give very rapid reduction. However, the use of Fe(NH 2 SO 3 ) 2 increases the volume of radioactive wastes, and the use of U(IV)-NH 2 NH 2 produces dangerous hydrazoic acid. On the other hand, Np content increases with increasing burnup. Fe 2+ can't separate both Pu and Np from U, and U(IV) can't control Np valence and lead Np go to different streams. Being capable of reducing Pu(IV) and Np(VI) to Pu(III) and Np(V) rapidly, N,N-diethylhydroxylamine (DEHA) is a promising reductan for applications of spent fuel reprocessing. By gas chromatography, chemical method and UV spectrophotometry, the liquid composition produced by radiation degradation of DEHA at different condition was studied qualitatively and quantitatively. The results show that with DEHA concentration of 0.1-0.5M irradiated to 10-1000 kGy, the main liquid composition is acetaldehyde, ethanol, acetic acid and ammonium. When the concentration of DEHA was 0.1-0.2M, the concentration of acetaldehyde ethanol,acetic acid and ammonium was lower than 0.03M. When the concentration of DEHA was 0.3-0.5M, the concentration of acetaldehyde,ethanol,acetic acid changed little, but ammonium concentration increases greatly, and the maximum was 0.16M. The degradation degree of DEHA decreased with the increasing of DEHA concentration. The degradation degree was 25% with DEHA concentration of 0.5M irradiated to 1000kGy. (authors)

  17. Anisotropic instability of the photoelectrons generated by soft x-ray radiation of the laser-produced plasma focus

    International Nuclear Information System (INIS)

    Klumov, B.A.; Tarakanov, V.P.

    1994-01-01

    The electron field with the anisotropic distribution function is being formed when the gas is being affected with ionizing radiation. The anisotropy of the distribution function occurs due to the fact that photoelectrons fly mainly in the direction perpendicular to that of ionizing radiation quantum propagation. In order to emphasize the most typical features of the developed anisotropic instability, photoelectrons were believed to fly strictly across the photon propagation direction. Two-dimensional electromagnetic particle simulations have been carried out to study high-frequency disturbances in the plasma produced by ionizing radiation. Elastic processes were taken into account. It has been shown, in particular, that the energy of anisotropic electrons transforms mainly into that of magnetic pulsations (approximately 7% of the energy transforms into that of magnetic pulsations). Development of the anisotropic instability result in a space stratification into current filaments. The anisotropic instability study can be important for an interpretation of electromagnetic emission spectra for a plasma disturbed by radiation

  18. The introduction of radiation monitor produced by several nuclear instrument factories

    International Nuclear Information System (INIS)

    Yu Liying

    2005-01-01

    The paper introduce some radiation monitor products of several nuclear instrument factories include Xi'an Nuclear Instrument Factory, MGP Instruments Inc, and Canberra Industries Inc. The introduction aspects include the range, configuration, and application of products. So, the paper is reference for the designer with responsibility for radiation monitoring system of new nuclear project. (authors)

  19. A critical analysis of shock models for chondrule formation

    Science.gov (United States)

    Stammler, Sebastian M.; Dullemond, Cornelis P.

    2014-11-01

    In recent years many models of chondrule formation have been proposed. One of those models is the processing of dust in shock waves in protoplanetary disks. In this model, the dust and the chondrule precursors are overrun by shock waves, which heat them up by frictional heating and thermal exchange with the gas. In this paper we reanalyze the nebular shock model of chondrule formation and focus on the downstream boundary condition. We show that for large-scale plane-parallel chondrule-melting shocks the postshock equilibrium temperature is too high to avoid volatile loss. Even if we include radiative cooling in lateral directions out of the disk plane into our model (thereby breaking strict plane-parallel geometry) we find that for a realistic vertical extent of the solar nebula disk the temperature decline is not fast enough. On the other hand, if we assume that the shock is entirely optically thin so that particles can radiate freely, the cooling rates are too high to produce the observed chondrules textures. Global nebular shocks are therefore problematic as the primary sources of chondrules.

  20. ON SHOCKS DRIVEN BY HIGH-MASS PLANETS IN RADIATIVELY INEFFICIENT DISKS. II. THREE-DIMENSIONAL GLOBAL DISK SIMULATIONS

    International Nuclear Information System (INIS)

    Lyra, Wladimir; Richert, Alexander J. W.; Boley, Aaron; Turner, Neal; Okuzumi, Satoshi; Flock, Mario; Mac Low, Mordecai-Mark

    2016-01-01

    Recent high-resolution, near-infrared images of protoplanetary disks have shown that these disks often present spiral features. Spiral arms are among the structures predicted by models of disk–planet interaction and thus it is tempting to suspect that planetary perturbers are responsible for these signatures. However, such interpretation is not free of problems. The observed spirals have large pitch angles, and in at least one case (HD 100546) it appears effectively unpolarized, implying thermal emission of the order of 1000 K (465 ± 40 K at closer inspection). We have recently shown in two-dimensional models that shock dissipation in the supersonic wake of high-mass planets can lead to significant heating if the disk is sufficiently adiabatic. Here we extend this analysis to three dimensions in thermodynamically evolving disks. We use the Pencil Code in spherical coordinates for our models, with a prescription for thermal cooling based on the optical depth of the local vertical gas column. We use a 5M J planet, and show that shocks in the region around the planet where the Lindblad resonances occur heat the gas to substantially higher temperatures than the ambient gas. The gas is accelerated vertically away from the midplane to form shock bores, and the gas falling back toward the midplane breaks up into a turbulent surf. This turbulence, although localized, has high α values, reaching 0.05 in the inner Lindblad resonance, and 0.1 in the outer one. We find evidence that the disk regions heated up by the shocks become superadiabatic, generating convection far from the planet’s orbit

  1. On Shocks Driven by High-mass Planets in Radiatively Inefficient Disks. II. Three-dimensional Global Disk Simulations

    Science.gov (United States)

    Lyra, Wladimir; Richert, Alexander J. W.; Boley, Aaron; Turner, Neal; Mac Low, Mordecai-Mark; Okuzumi, Satoshi; Flock, Mario

    2016-02-01

    Recent high-resolution, near-infrared images of protoplanetary disks have shown that these disks often present spiral features. Spiral arms are among the structures predicted by models of disk-planet interaction and thus it is tempting to suspect that planetary perturbers are responsible for these signatures. However, such interpretation is not free of problems. The observed spirals have large pitch angles, and in at least one case (HD 100546) it appears effectively unpolarized, implying thermal emission of the order of 1000 K (465 ± 40 K at closer inspection). We have recently shown in two-dimensional models that shock dissipation in the supersonic wake of high-mass planets can lead to significant heating if the disk is sufficiently adiabatic. Here we extend this analysis to three dimensions in thermodynamically evolving disks. We use the Pencil Code in spherical coordinates for our models, with a prescription for thermal cooling based on the optical depth of the local vertical gas column. We use a 5MJ planet, and show that shocks in the region around the planet where the Lindblad resonances occur heat the gas to substantially higher temperatures than the ambient gas. The gas is accelerated vertically away from the midplane to form shock bores, and the gas falling back toward the midplane breaks up into a turbulent surf. This turbulence, although localized, has high α values, reaching 0.05 in the inner Lindblad resonance, and 0.1 in the outer one. We find evidence that the disk regions heated up by the shocks become superadiabatic, generating convection far from the planet’s orbit.

  2. Microgravity Experiment: The Fate of Confined Shock Waves

    Science.gov (United States)

    Kobel, P.; Obreschkow, D.; Dorsaz, N.; de Bosset, A.; Farhat, M.

    2007-11-01

    Shockwave induced cavitation is a form of hydrodynamic cavitation generated by the interaction of shock waves with vapor nuclei and microscopic impurities. Both the shock waves and the induced cavitation are known as sources of erosion damage in hydraulic industrial systems and hence represent an important research topic in fluid dynamics. Here we present the first investigation of shock wave induced cavitation inside closed and isolated liquid volumes, which confine the shock wave by reflections and thereby promise a particularly strong coupling with cavitation. A microgravity platform (ESA, 42^nd parabolic flight campaign) was used to produce stable water drops with centimetric diameters. Inside these drops, a fast electrical discharge was generated to release a strong shock wave. This setting results in an amplified form of shockwave induced cavitation, visible in high-speed images as a transient haze of sub-millimetric bubbles synchronized with the shockwave radiation. A comparison between high-speed visualizations and 3D simulations of a shock front inside a liquid sphere reveals that focus zones within the drop lead to a significantly increased density of induced cavitation. Considering shock wave crossing and focusing may hence prove crucially useful to understand the important process of cavitation erosion.

  3. Applications of first order matricial theory to the calculation of storage ring designed for producing synchrotron radiation

    International Nuclear Information System (INIS)

    Machado, J.M.

    1984-01-01

    A review of first order matrix theory (linear approximation) used for calculating component elements of a particle accelerator employing the synchrotron principle of alternated gradient, is presented. Based on this theory, criteria for dimensioning synchrotron designed, exclusively for producing electromagnetic radiation, are established. The problem to find out optimum disposition of elements (straight line sections, quadrupolar magnetic lens, etc.) which take advantages of deflector magnets of the DCI synchrotron (Orsay Linear Accelerator Laboratory, French) aiming to construct a synchrotron designed to operate as electromagnetic radiation source, is solved. (M.C.K.) [pt

  4. Simultaneos determination of absorbed doses due to beta and gamma radiations with CaSO4: Dy produced at Ipen

    International Nuclear Information System (INIS)

    Campos, L.L.; Rosa, L.A.R. da.

    1988-07-01

    Due to the Goiania radiological accident, it was necessary to develop urgently a dosimeter in order to evaluate, simultaneously, beta and gamma absorbed doses, due to 137 Cs radiations. Therefore, the Dosimetric Material Production Laboratory of IPEN developed a simple, practical, light and low cost badge using small thickness (0,20mm) thermoluminescent CaSO 4 : Dy pellets produced by the same laboratory. This pellets are adequate for beta radiation detection. These dosimeters were worn by some IPEN technicians who worked in Goiania city, and were used to evaluate the external and internal contaminations presented by the accident victims interned at the Hospital Naval Marcilio Dias. (author) [pt

  5. Ionizing radiation post-curing of objects produced by stereolithography and other methods

    Science.gov (United States)

    Howell, David H.; Eberle, Claude C.; Janke, Christopher J.

    2000-01-01

    An object comprised of a curable material and formed by stereolithography or another three-dimensional prototyping method, in which the object has undergone initial curing, is subjected to post-curing by ionizing radiation, such as an electron beam having a predetermined beam output energy, which is applied in a predetermined dosage and at a predetermined dose rate. The post-cured object exhibits a property profile which is superior to that which existed prior to the ionizing radiation post-curing.

  6. Time- and dose-dependent changes in neuronal activity produced by X radiation in brain slices

    International Nuclear Information System (INIS)

    Pellmar, T.C.; Schauer, D.A.; Zeman, G.H.

    1990-01-01

    A new method of exposing tissues to X rays in a lead Faraday cage has made it possible to examine directly radiation damage to isolated neuronal tissue. Thin slices of hippocampus from brains of euthanized guinea pigs were exposed to 17.4 ke V X radiation. Electrophysiological recordings were made before, during, and after exposure to doses between 5 and 65 Gy at a dose rate of 1.54 Gy/min. Following exposure to doses of 40 Gy and greater, the synaptic potential was enhanced, reaching a steady level soon after exposure. The ability of the synaptic potential to generate a spike was reduced and damage progressed after termination of the radiation exposure. Recovery was not observed following termination of exposure. These results demonstrate that an isolated neuronal network can show complex changes in electrophysiological properties following moderate doses of ionizing radiation. An investigation of radiation damage directly to neurons in vitro will contribute to the understanding of the underlying mechanisms of radiation-induced nervous system dysfunction

  7. Influence of mutations in some structural genes of heat-shock proteins on radiation resistance of Escherichia coli

    International Nuclear Information System (INIS)

    Verbenko, V.N.; Kuznetsova, L.V.; Bikineeva, E.G.; Kalinin, V.L.

    1992-01-01

    Lethal effects of γ-irradiation were studied in Escherichia coli strains with normal repair genotype and in radiation-resistant Gam r strains, both carrying additional mutations in the structural genes dnaK, grpE, groES or groEL. The null mutation ΔdnaK52::Cm r enhanced radiation sensitivity of wild-type cells and abolished the effect of heat induced rediation-resistance (ETIRR) and elevated radiation resistance of the Gam r strains

  8. STEREO interplanetary shocks and foreshocks

    International Nuclear Information System (INIS)

    Blanco-Cano, X.; Kajdič, P.; Aguilar-Rodríguez, E.; Russell, C. T.; Jian, L. K.; Luhmann, J. G.

    2013-01-01

    We use STEREO data to study shocks driven by stream interactions and the waves associated with them. During the years of the extended solar minimum 2007-2010, stream interaction shocks have Mach numbers between 1.1-3.8 and θ Bn ∼20-86°. We find a variety of waves, including whistlers and low frequency fluctuations. Upstream whistler waves may be generated at the shock and upstream ultra low frequency (ULF) waves can be driven locally by ion instabilities. The downstream wave spectra can be formed by both, locally generated perturbations, and shock transmitted waves. We find that many quasiperpendicular shocks can be accompanied by ULF wave and ion foreshocks, which is in contrast to Earth's bow shock. Fluctuations downstream of quasi-parallel shocks tend to have larger amplitudes than waves downstream of quasi-perpendicular shocks. Proton foreshocks of shocks driven by stream interactions have extensions dr ≤0.05 AU. This is smaller than foreshock extensions for ICME driven shocks. The difference in foreshock extensions is related to the fact that ICME driven shocks are formed closer to the Sun and therefore begin to accelerate particles very early in their existence, while stream interaction shocks form at ∼1 AU and have been producing suprathermal particles for a shorter time.

  9. STEREO interplanetary shocks and foreshocks

    Energy Technology Data Exchange (ETDEWEB)

    Blanco-Cano, X. [Instituto de Geofisica, UNAM, CU, Coyoacan 04510 DF (Mexico); Kajdic, P. [IRAP-University of Toulouse, CNRS, Toulouse (France); Aguilar-Rodriguez, E. [Instituto de Geofisica, UNAM, Morelia (Mexico); Russell, C. T. [ESS and IGPP, University of California, Los Angeles, 603 Charles Young Drive, Los Angeles, CA 90095 (United States); Jian, L. K. [NASA Goddard Space Flight Center, Greenbelt, MD and University of Maryland, College Park, MD (United States); Luhmann, J. G. [SSL, University of California Berkeley (United States)

    2013-06-13

    We use STEREO data to study shocks driven by stream interactions and the waves associated with them. During the years of the extended solar minimum 2007-2010, stream interaction shocks have Mach numbers between 1.1-3.8 and {theta}{sub Bn}{approx}20-86 Degree-Sign . We find a variety of waves, including whistlers and low frequency fluctuations. Upstream whistler waves may be generated at the shock and upstream ultra low frequency (ULF) waves can be driven locally by ion instabilities. The downstream wave spectra can be formed by both, locally generated perturbations, and shock transmitted waves. We find that many quasiperpendicular shocks can be accompanied by ULF wave and ion foreshocks, which is in contrast to Earth's bow shock. Fluctuations downstream of quasi-parallel shocks tend to have larger amplitudes than waves downstream of quasi-perpendicular shocks. Proton foreshocks of shocks driven by stream interactions have extensions dr {<=}0.05 AU. This is smaller than foreshock extensions for ICME driven shocks. The difference in foreshock extensions is related to the fact that ICME driven shocks are formed closer to the Sun and therefore begin to accelerate particles very early in their existence, while stream interaction shocks form at {approx}1 AU and have been producing suprathermal particles for a shorter time.

  10. Radition mutagenesis in lavender. Part 2. Effect of heat shock, moisture and post radiation storage on lavender seed radiosensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Raev, R.C. (Institute of the Rose, Essential Oil and Medicinal Plants, Kazanlyk (Bulgaria))

    1983-01-01

    The influence of three factors which increase radiation tolerance of lavender seeds and reduce the biological injuries with lethal effect in case of gamma-irradiation (Cs/sup 137/) was investigated. Irradiation at -65 deg C increased radiation tolerance and led to increased doses and higher mutagenic effect. Seeds with lowered moisture had higher radiosensitivity in comparison to these having 4.5-5 times more water. Post-radiation storage at 20-22 deg C without loss of moisture increased radiation injuries, which grew along with the prolongation of the period from seed irradiation to germination.

  11. Study on radiation degradation of hydroxylamine derivatives. Pt.2: The qualitative and quantitative analysis of light hydrocarbons produced by radiation degradation of N, N-diethyl hydroxylamine

    International Nuclear Information System (INIS)

    Wang Jinhua; Bao Borong; Wu Minghong; Sun Xilian

    2004-01-01

    The qualitative and quantitative analysis of light hydrocarbons produced by radiation degradation of N,N-diethyl hydroxylamine are reported. These analyses are performed on the gas chromatography in which a porous layer open tubular column coated with aluminum oxide and a flame-ionization detector are used. When the doses are between 10 and 1000 kGy, the main hydrocarbons produced by radiation degradation of N,N-diethyl hydroxylamine are methane, ethane, ethene, propane and n-butane. The volume fraction of methane, ethane, n-butane and propane are increased with the increase of dose. The volume fraction of ethene is also increased with the increase of dose at first, however, when the absorbed dose is higher than 500 kGy. The volume fraction of ethene is decreased with the increase of dose

  12. Ferrites based infrared radiation coatings with high emissivity and high thermal shock resistance and their application on energy-saving kettle

    International Nuclear Information System (INIS)

    Zhang, Jianyi; Fan, Xi’an; Lu, Lei; Hu, Xiaoming; Li, Guangqiang

    2015-01-01

    Highlights: • The ferrites based infrared radiation coating was prepared by HVOF for the first time. • The infrared radiation coatings were applied firstly on the household kettle. • The bonding strength between the coating and substrate could reach 30.7 MPa. • The coating kept intact when cycle reached 27 by quenching from 1000 °C using water. • The energy-saving efficiency of the kettle with coating could reach 30.5%. - Abstract: Starting from Fe 2 O 3 , MnO 2 , Co 2 O 3 and NiO powders, the ferrites based infrared radiation coatings with high emissivity and high thermal shock resistance were successfully prepared on the surface of carbon steel by high velocity oxy-fuel spraying (HVOF). The coating thickness was about 120–150 μm and presented a typical flat lamellar structure. The coating surface was rough and some submicron grade grains distributed on it. The infrared emissivity of the ferrites based coating by HVOF was over 0.74 in 3–20 μm waveband at 800 °C, which was obviously higher than that of the coating by brushing process in the short waveband. The bonding strength was 30.7 MPa between the coating and substrate, which was five times more than that of conventional coatings by brushing process. The combined effect of the superior bonding strength, typical lamellar structure, pre-existing microcracks and newly generated pores made the cycle times reach 27 when the coating samples were quenched from 1000 °C using water. Lastly, the infrared radiation coatings were applied on the underside of household kettle, and the energy-saving efficiency could reach 30.5%. The ferrites based infrared radiation coatings obtained in this work are good candidates for saving energy in the field of cookware and industrial high temperature furnace

  13. Demonstration of radiation pulse shaping with nested-tungsten-wire-array pinches for high-yield inertial confinement fusion.

    Science.gov (United States)

    Cuneo, M E; Vesey, R A; Sinars, D B; Chittenden, J P; Waisman, E M; Lemke, R W; Lebedev, S V; Bliss, D E; Stygar, W A; Porter, J L; Schroen, D G; Mazarakis, M G; Chandler, G A; Mehlhorn, T A

    2005-10-28

    Nested wire-array pinches are shown to generate soft x-ray radiation pulse shapes required for three-shock isentropic compression and hot-spot ignition of high-yield inertial confinement fusion capsules. We demonstrate a reproducible and tunable foot pulse (first shock) produced by interaction of the outer and inner arrays. A first-step pulse (second shock) is produced by inner array collision with a central CH2 foam target. Stagnation of the inner array at the axis produces the third shock. Capsules optimized for several of these shapes produce 290-900 MJ fusion yields in 1D simulations.

  14. Radiation protection principles applied to conventional industries producing deleterious environmental effects

    International Nuclear Information System (INIS)

    Tadmor, J.

    1980-01-01

    Comparison of the radiation protection standards, for the population at large, with the conventional pollutants ambient standards, reveals differences in basic principles which result in more relaxed ambient standards for conventional pollutants and consequently, the penalization of the nuclear industry, due to the increased cost of its safety measures. It is proposed that radiation protection principles should be used as a prototype for pollutants having harmful environmental effects and that radiation health physicists should be active in the application of these principles of population protection. A case study of atmospheric release of SO 2 , under different conditions, is analyzed, to emphasize the importance of consideration of the size of the exposed population. (H.K.)

  15. Radiation embrittlement of WWER 440 pressure vessel steel and of some improved steels by western producers

    International Nuclear Information System (INIS)

    Koutsky, J.; Vacek, M.; Stoces, B.; Pav, T.; Otruba, J.; Novosad, P.; Brumovsky, M.

    1982-01-01

    The resistance was studied of Cr-Mo-V type steel 15Kh2MFA to radiation embrittlement at an irradiation temperature of around 288 degC. Studied was the steel used for the manufacture of the pressure vessel of the Paks nuclear reactor in Hungary. The obtained results of radiation embrittlement and hardening of steel 15Kh2MFA were compared with similar values of Mn-Ni-Mo type steels A 533-B and A 508 manufactured by leading western manufacturers within the international research programme coordinated by the IAEA. It was found that the resistance of steel 15Kh2MFA to radiation embrittlement is comparable with steels A 533-B and A 508 by western manufacturers. (author)

  16. Qualitative and quantitative analysis of light hydrocarbons produced by radiation degradation of N, N-dimethyl hydroxylamine

    International Nuclear Information System (INIS)

    Wang Jinhua; Bao Borong; Wu Minghong; Sun Xilian; Zhang Xianye; Hu Jingxin; Ye Guoan

    2004-01-01

    This paper reports the qualitative and quantitative analysis of light hydrocarbons produced by radiation degradation of N, N-dimethyl hydroxylamine. These analyses were performed on the gas chromatograph, in which porous layer open tubular column coated with aluminum oxide and flame-ionization detector are used. For the doses between 10 and 1000 kGy, the light hydrocarbons produced by radiation degradation of N,N-dimethyl hydroxylamine are methane, ethane, ethene, propane, propene and n-butane. When the concentration of N,N-dimethyl hydroxylamine is 0.2 mol/L, the volume fraction of methane is (9.996-247.5) x 10 -6 , the volume fraction of ethane, propane and n-butane is lower and that of ethene and propene is much lower. With the increase of dose the volume fraction of methane is increased but the volume fraction of ethane, ethene, propane, propene and n-butane is not obviously changed. (authors)

  17. The acute effects of ionizing radiation on DNA synthesis and the development of antibody-producing cells

    International Nuclear Information System (INIS)

    Harris, G.; Olsen, I.; Cramp, W.A.

    1981-01-01

    Ionizing radiation inhibited the development of specific haemolysin-producing cells (PFC) and depressed the incorporation of ( 3 H) thymidine by rabbit spleen explants responding to SRC in the culture medium. In contrast to these effects, the rates of incorporation of precursors for protein and RNA synthesis were much less affected. The depression of ( 3 H) thymidine incorporation was found to result from a quantitative reduction of new DNA synthesis, without any change in the proportion of labelled cells, at any time after irradiation. The DNA synthesis occurring in these cells preparing to develop antibody-producing capacity was thus radio-sensitive, but the exact nature of the defect resulting from exposure to radiation requires further study. (orig.)

  18. Laser-produced lithium plasma as a narrow-band extended ultraviolet radiation source for photoelectron spectroscopy.

    Science.gov (United States)

    Schriever, G; Mager, S; Naweed, A; Engel, A; Bergmann, K; Lebert, R

    1998-03-01

    Extended ultraviolet (EUV) emission characteristics of a laser-produced lithium plasma are determined with regard to the requirements of x-ray photoelectron spectroscopy. The main features of interest are spectral distribution, photon flux, bandwidth, source size, and emission duration. Laser-produced lithium plasmas are characterized as emitters of intense narrow-band EUV radiation. It can be estimated that the lithium Lyman-alpha line emission in combination with an ellipsoidal silicon/molybdenum multilayer mirror is a suitable EUV source for an x-ray photoelectron spectroscopy microscope with a 50-meV energy resolution and a 10-mum lateral resolution.

  19. X-ray study of bow shocks in runaway stars

    Science.gov (United States)

    De Becker, M.; del Valle, M. V.; Romero, G. E.; Peri, C. S.; Benaglia, P.

    2017-11-01

    Massive runaway stars produce bow shocks through the interaction of their winds with the interstellar medium, with the prospect for particle acceleration by the shocks. These objects are consequently candidates for non-thermal emission. Our aim is to investigate the X-ray emission from these sources. We observed with XMM-Newton a sample of five bow shock runaways, which constitutes a significant improvement of the sample of bow shock runaways studied in X-rays so far. A careful analysis of the data did not reveal any X-ray emission related to the bow shocks. However, X-ray emission from the stars is detected, in agreement with the expected thermal emission from stellar winds. On the basis of background measurements we derive conservative upper limits between 0.3 and 10 keV on the bow shocks emission. Using a simple radiation model, these limits together with radio upper limits allow us to constrain some of the main physical quantities involved in the non-thermal emission processes, such as the magnetic field strength and the amount of incident infrared photons. The reasons likely responsible for the non-detection of non-thermal radiation are discussed. Finally, using energy budget arguments, we investigate the detectability of inverse Compton X-rays in a more extended sample of catalogued runaway star bow shocks. From our analysis we conclude that a clear identification of non-thermal X-rays from massive runaway bow shocks requires one order of magnitude (or higher) sensitivity improvement with respect to present observatories.

  20. Evolution of the legislation concerning the professional diseases considered as produced by ionized radiation

    International Nuclear Information System (INIS)

    Hebert, J.

    2004-01-01

    After having remind the history and structure of the classical French system of compensation of occupational diseases, conditions put to insert such of these diseases induced by ionizing radiations are studied, before to conclude by an exam of solutions that a new system introduced by an act of 27 of January 1993 could offer in some situations. (author)

  1. Specific chemical and structural damage to proteins produced by synchrotron radiation.

    Science.gov (United States)

    Weik, M; Ravelli, R B; Kryger, G; McSweeney, S; Raves, M L; Harel, M; Gros, P; Silman, I; Kroon, J; Sussman, J L

    2000-01-18

    Radiation damage is an inherent problem in x-ray crystallography. It usually is presumed to be nonspecific and manifested as a gradual decay in the overall quality of data obtained for a given crystal as data collection proceeds. Based on third-generation synchrotron x-ray data, collected at cryogenic temperatures, we show for the enzymes Torpedo californica acetylcholinesterase and hen egg white lysozyme that synchrotron radiation also can cause highly specific damage. Disulfide bridges break, and carboxyl groups of acidic residues lose their definition. Highly exposed carboxyls, and those in the active site of both enzymes, appear particularly susceptible. The catalytic triad residue, His-440, in acetylcholinesterase, also appears to be much more sensitive to radiation damage than other histidine residues. Our findings have direct practical implications for routine x-ray data collection at high-energy synchrotron sources. Furthermore, they provide a direct approach for studying the radiation chemistry of proteins and nucleic acids at a detailed, structural level and also may yield information concerning putative "weak links" in a given biological macromolecule, which may be of structural and functional significance.

  2. The Heliospheric Termination Shock

    Science.gov (United States)

    Jokipii, J. R.

    2013-06-01

    The heliospheric termination shock is a vast, spheroidal shock wave marking the transition from the supersonic solar wind to the slower flow in the heliosheath, in response to the pressure of the interstellar medium. It is one of the most-important boundaries in the outer heliosphere. It affects energetic particles strongly and for this reason is a significant factor in the effects of the Sun on Galactic cosmic rays. This paper summarizes the general properties and overall large-scale structure and motions of the termination shock. Observations over the past several years, both in situ and remote, have dramatically revised our understanding of the shock. The consensus now is that the shock is quite blunt, is with the front, blunt side canted at an angle to the flow direction of the local interstellar plasma relative to the Sun, and is dynamical and turbulent. Much of this new understanding has come from remote observations of energetic charged particles interacting with the shock, radio waves and radiation backscattered from interstellar neutral atoms. The observations and the implications are discussed.

  3. Steady flow on to a conveyor belt - Causal viscosity and shear shocks

    Science.gov (United States)

    Syer, D.; Narayan, Ramesh

    1993-01-01

    Some hydrodynamical consequences of the adoption of a causal theory of viscosity are explored. Causality is introduced into the theory by letting the coefficient of viscosity go to zero as the flow velocity approaches a designated propagation speed for viscous signals. Consideration is given to a model of viscosity which has a finite propagation speed of shear information, and it is shown that it produces two kinds of shear shock. A 'pure shear shock' corresponds to a transition from a superviscous to a subviscous state with no discontinuity in the velocity. A 'mixed shear shock' has a shear transition occurring at the same location as a normal adiabatic or radiative shock. A generalized version of the Rankine-Hugoniot conditions for mixed shear shocks is derived, and self-consistent numerical solutions to a model 2D problem in which an axisymmetric radially infalling stream encounters a spinning star are presented.

  4. Acid-producing capacity from sugars and sugar alcohols among Lactobacillus isolates collected in connection with radiation therapy.

    Science.gov (United States)

    Almståhl, Annica; Rudbäck, Helena; Basic, Amina; Carlén, Anette; Alstad, Torgny

    2017-12-01

    To investigate the acid-producing capacity from sugars and sugar alcohols of oral Lactobacillus collected in connection with radiation therapy (RT) to the head and neck region. Lactobacillus were collected from the tongue, buccal mucosa and supragingival plaque in 24 patients before, during, and after RT. The acid-producing capacity of Lactobacillus isolates (n=211) was analyzed using a colorimetric fermentation test in microtiter plates. Solutions containing 2% sugars (sucrose, glucose, fructose, lactose) or sugar-alcohols (sorbitol and xylitol) were used. After 24h of incubation, bacterial acid-producing capacity was determined as strong (pH6). Data regarding intake frequency of sugar-rich products and products with sugar-alcohols was collected. The highest acid-producing capacity using the sugars was seen for isolates collected during RT. Sorbitol was fermented to a higher extent during and post RT, especially among isolates from plaque. Lactobacillus fermenting xylitol showed the highest acid-producing capacity during RT (psugar-rich products or sugar-alcohol containing products and Lactobacillus acid-producing capacity, were found. The results suggest that Lactobacillus isolates, collected from the tongue, buccal mucosa and supragingival plaque, have a higher acid-producing capacity using sugars and sugar-alcohols during RT than one year post RT. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Visual expression analysis of the responses of the alternative oxidase gene (aox1) to heat shock, oxidative, and osmotic stresses in conidia of citric acid-producing Aspergillus niger.

    Science.gov (United States)

    Honda, Yuki; Hattori, Takasumi; Kirimura, Kohtaro

    2012-03-01

    The citric acid-producing filamentous fungus Aspergillus niger WU-2223L shows cyanide-insensitive respiration catalyzed by alternative oxidase in addition to the cytochrome pathway. Sequence analysis of the 5' flanking region of the alternative oxidase gene (aox1) revealed a potential heat shock element (HSE) and a stress response element (STRE). We have previously confirmed aox1 expression in conidia. In this study, to confirm whether the upstream region of aox1 responds to various stresses, we used a visual expression analysis system for single-cell conidia of the A. niger strain AOXEGFP-1. This strain harbored a fusion gene comprising aox1 and egfp, which encodes the enhanced green fluorescent protein (EGFP). The fluorescence intensity of EGFP increased in conidia of A. niger AOXEGFP-1 that were subjected to heat shock at 35-45 °C, oxidative stress by exposure to 5mM paraquat or 1 mM t-butylhydroperoxide, or osmotic stresses by exposure to 0.5 M KCl or 1.0 M mannitol. These results indicate that the putative HSE and STRE in the upstream region of aox1 directly or indirectly respond to heat shock, oxidative, and osmotic stresses. Copyright © 2011 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  6. Curved Radio Spectra of Weak Cluster Shocks

    Science.gov (United States)

    Kang, Hyesung; Ryu, Dongsu

    2015-08-01

    In order to understand certain observed features of arc-like giant radio relics such as the rareness, uniform surface brightness, and curved integrated spectra, we explore a diffusive shock acceleration (DSA) model for radio relics in which a spherical shock impinges on a magnetized cloud containing fossil relativistic electrons. Toward this end, we perform DSA simulations of spherical shocks with the parameters relevant for the Sausage radio relic in cluster CIZA J2242.8+5301, and calculate the ensuing radio synchrotron emission from re-accelerated electrons. Three types of fossil electron populations are considered: a delta-function like population with the shock injection momentum, a power-law distribution, and a power law with an exponential cutoff. The surface brightness profile of the radio-emitting postshock region and the volume-integrated radio spectrum are calculated and compared with observations. We find that the observed width of the Sausage relic can be explained reasonably well by shocks with speed {u}{{s}}˜ 3× {10}3 {km} {{{s}}}-1 and sonic Mach number {M}{{s}}˜ 3. These shocks produce curved radio spectra that steepen gradually over (0.1-10){ν }{br} with a break frequency {ν }{br}˜ 1 GHz if the duration of electron acceleration is ˜60-80 Myr. However, the abrupt increase in the spectral index above ˜1.5 GHz observed in the Sausage relic seems to indicate that additional physical processes, other than radiative losses, operate for electrons with {γ }{{e}}≳ {10}4.

  7. Determination of patulin producing activity and radiation sensitivity of fungisolated from Korean apples

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Ho; Jo, Min Ho [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2017-06-15

    Patulin is a mycotoxin produced by a variety of molds, especially within genera Penicillium, Aspergillus and Byssochlamys growing on various fruits. In this study, patulin producing activities and the effects of a gamma irradiation on the control and/or sterilization of fungal strains isolated from Korean apples, Malus pumila var. dulcissima, were evaluated. Nine fungal strains; five strains of genus Penicillium and one strains of genus Glomerella, Giberella, Alternaria and Galactomyces were isolated and identified by the similarity analysis based on the nucleotide sequence of the ITS5-5.8S-ITS4 region. Among the isolated strains, four Penicillium strains and a Glomerella showed patulin producing activities. The maximal patulin-producing activity of P. griseofulvum ATCC 46037, a standard strain of patulin-producing fungi, was 1,211.5 ppm in a 5-GYEP broth medium, while those of the isolated fungi reached to 27.4⁓134.2 ppm. Patulin-producing levels were dependent on the carbon sources and maximal production of the patulin by P. griseofulvum, P. crustosum, I-3, I-6, I-7 and I-8 was observed in a broth media containing glycerol, fructose, glycerol, glucose, lactose and fructose, respectively. The D10-values of the conidia of tested strains in an aqueous suspension were calculated in the range of 0.25⁓0.64 kGy. In conclusion, although the patulin producing activities of the isolated fungi were significantly lower than those of standard strains, it cannot deny the possibility of an patulin contamination of the Korean apples. Therefore, gamma ray irradiation (1.0 kGy) after harvest of apples could be applied to prevent the growth of a patulin producing molds for a safe distribution.

  8. Determination of patulin producing activity and radiation sensitivity of fungisolated from Korean apples

    International Nuclear Information System (INIS)

    Kim, Dong Ho; Jo, Min Ho

    2017-01-01

    Patulin is a mycotoxin produced by a variety of molds, especially within genera Penicillium, Aspergillus and Byssochlamys growing on various fruits. In this study, patulin producing activities and the effects of a gamma irradiation on the control and/or sterilization of fungal strains isolated from Korean apples, Malus pumila var. dulcissima, were evaluated. Nine fungal strains; five strains of genus Penicillium and one strains of genus Glomerella, Giberella, Alternaria and Galactomyces were isolated and identified by the similarity analysis based on the nucleotide sequence of the ITS5-5.8S-ITS4 region. Among the isolated strains, four Penicillium strains and a Glomerella showed patulin producing activities. The maximal patulin-producing activity of P. griseofulvum ATCC 46037, a standard strain of patulin-producing fungi, was 1,211.5 ppm in a 5-GYEP broth medium, while those of the isolated fungi reached to 27.4⁓134.2 ppm. Patulin-producing levels were dependent on the carbon sources and maximal production of the patulin by P. griseofulvum, P. crustosum, I-3, I-6, I-7 and I-8 was observed in a broth media containing glycerol, fructose, glycerol, glucose, lactose and fructose, respectively. The D10-values of the conidia of tested strains in an aqueous suspension were calculated in the range of 0.25⁓0.64 kGy. In conclusion, although the patulin producing activities of the isolated fungi were significantly lower than those of standard strains, it cannot deny the possibility of an patulin contamination of the Korean apples. Therefore, gamma ray irradiation (1.0 kGy) after harvest of apples could be applied to prevent the growth of a patulin producing molds for a safe distribution

  9. Application of Ionizing Radiations to Produce New Polysaccharides and Proteins with Enhanced Functionality

    International Nuclear Information System (INIS)

    Al Assaf, S.

    2006-01-01

    Treatment of polysaccharides with ionizing radiation either in the solid state or in aqueous solution leads to degradation, whereas application of radiation to process synthetic polymers to introduce structural changes and special performance characteristics is now a thriving industry. Using a mediating gas associated during the radiation treatment prevents the degradation of natural polymers and enables the introduction of different molecular and functional characteristics, as previously achieved with synthetic polymers. For example, the molecular weight can be increased and standardised, protein distribution reorganised and modified to ensure better emulsification, viscosity and viscoelasticity enhanced, leading when required to hydrogel formation. More than one hydrocolloid can also be integrated into a single matrix using this process. Protein, within demineralised bone, too can be modified to give enhanced osteoinductive capacity. This experience has led to additional patented and proprietary processes, using standard food processing techniques, to promote changes in a wide range of hydrocolloids which emulates and extend those which occur naturally. The lecture will describe these structural changes and their functional role by reference to several hydrocolloids, including acacia gums, pectin, ispaghula and hyaluronan, bone morphogenic protein. Applications in food products, dietary fibre and medical products will be illustrated

  10. Properties of cellulose derivatives produced from radiation-Modified cellulose pulps

    International Nuclear Information System (INIS)

    Iller, Edward; Stupinska, Halina; Starostka, Pawel

    2007-01-01

    The aim of project was elaboration of radiation methods for properties modification of cellulose pulps using for derivatives production. The selected cellulose pulps were exposed to an electron beam with energy 10 MeV in a linear accelerator. After irradiation pulps underwent the structural and physico-chemical investigations. The laboratory test for manufacturing carboxymethylocellulose (CMC), cellulose carbamate (CC) and cellulose acetate (CA) with cellulose pulps irradiated dose 10 and 15 kGy have been performed. Irradiation of the pulp influenced its depolimerisation degree and resulted in the drop of viscosity of CMC. However, the expected level of cellulose activation expressed as a rise of the substitution degree or increase of the active substance content in the CMC sodium salt was not observed. In the case of cellulose esters (CC, CA) formation, the action of ionising radiation on cellulose pulps with the dose 10 and 15 kGy enables obtaiment of the average values of polimerisation degree as required for CC soluble in aqueous sodium hydroxide solution. The properties of derivatives prepared by means of radiation and classic methods were compared

  11. Some biochemical consequences of the spatial distribution of ionizing radiation-produced free radicals

    International Nuclear Information System (INIS)

    Ward, J.F.

    1981-01-01

    Ionizing radiation deposits energy nonhomogeneously in the medium through which it passes. Mozumder and Magee (Radiat. Res. 28, 203-214(1966)) have classified the events as spurs, blobs, and short tracks. These are defined by size and amount of energy deposited. Thus the initial chemically reactive species are distributed in an inhomogeneous manner. In these volumes of high radical concentration, radical-radical reactions can occur which can only be scavenged by solutes at high concentration. Making the reasonable assumption that similar events occur intracellularly, the consequences of such events must be considered. In the case of DNA, several authors have shown that OH radicals diffuse only tens of angstroms prior to reaction. In the volume from which these radicals originate, DNA is necessarily at high concentration and consequently will interact with the radicals formed in the spur, etc. Such events are probably the source of radiation-production double-strand breaks in cellular DNA. However, the radicals cause other types of damage than strand breaks-potential strand breaks and base damage. An attempt is made to present the interrelation of multiply damaged sites - their constitution, the problems they present to cell repair mechanisms, and their possible relationship to cell survival

  12. CARS measurement of vibrational and rotational temperature with high power laser and high speed visualization of total radiation behind hypervelocity shock waves of 5-7km/s

    Science.gov (United States)

    Sakurai, Kotaro; Bindu, Venigalla Hima; Niinomi, Shota; Ota, Masanori; Maeno, Kazuo

    2010-09-01

    Coherent Anti-Stokes Raman Spectroscopy (CARS) method is commonly used for measuring molecular structure or condition. In the aerospace technology, this method is applies to measure the temperature in thermic fluid with relatively long time duration of millisecond or sub millisecond. On the other hand, vibrational/rotational temperatures behind hypervelocity shock wave are important for heat-shield design in phase of reentry flight. The non-equilibrium flow with radiative heating from strongly shocked air ahead of the vehicles plays an important role on the heat flux to the wall surface structure as well as convective heating. In this paper CARS method is applied to measure the vibrational/rotational temperature of N2 behind hypervelocity shock wave. The strong shock wave in front of the reentering space vehicles can be experimentally realigned by free-piston, double-diaphragm shock tube with low density test gas. However CARS measurement is difficult for our experiment. Our measurement needs very short pulse which order of nanosecond and high power laser for CARS method. It is due to our measurement object is the momentary phenomena which velocity is 7km/s. In addition the observation section is low density test gas, and there is the strong background light behind the shock wave. So we employ the CARS method with high power, order of 1J/pulse, and very short pulse (10ns) laser. By using this laser the CARS signal can be acquired even in the strong radiation area. Also we simultaneously try to use the CCD camera to obtain total radiation with CARS method.

  13. Spectrum and light curve of a supernova shock breakout through a thick Wolf-Rayet wind

    Energy Technology Data Exchange (ETDEWEB)

    Svirski, Gilad; Nakar, Ehud, E-mail: swirskig@post.tau.ac.il [Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel)

    2014-06-20

    Wolf-Rayet stars are known to eject winds. Thus, when a Wolf-Rayet star explodes as a supernova, a fast (≳ 40, 000 km s{sup –1}) shock is expected to be driven through a wind. We study the signal expected from a fast supernova shock propagating through an optically thick wind and find that the electrons behind the shock driven into the wind are efficiently cooled by inverse Compton over soft photons that were deposited by the radiation-mediated shock that crossed the star. Therefore, the bolometric luminosity is comparable to the kinetic energy flux through the shock, and the spectrum is found to be a power law, whose slope and frequency range depend on the number flux of soft photons available for cooling. Wolf-Rayet supernovae that explode through a thick wind have a high flux of soft photons, producing a flat spectrum, νF {sub ν} = Const, in the X-ray range of 0.1 ≲ T ≲ 50 keV. As the shock expands into an optically thin wind, the soft photons are no longer able to cool the shock that plows through the wind, and the bulk of the emission takes the form of a standard core-collapse supernova (without a wind). However, a small fraction of the soft photons is upscattered by the shocked wind and produces a transient unique X-ray signature.

  14. Spectrum and light curve of a supernova shock breakout through a thick Wolf-Rayet wind

    International Nuclear Information System (INIS)

    Svirski, Gilad; Nakar, Ehud

    2014-01-01

    Wolf-Rayet stars are known to eject winds. Thus, when a Wolf-Rayet star explodes as a supernova, a fast (≳ 40, 000 km s –1 ) shock is expected to be driven through a wind. We study the signal expected from a fast supernova shock propagating through an optically thick wind and find that the electrons behind the shock driven into the wind are efficiently cooled by inverse Compton over soft photons that were deposited by the radiation-mediated shock that crossed the star. Therefore, the bolometric luminosity is comparable to the kinetic energy flux through the shock, and the spectrum is found to be a power law, whose slope and frequency range depend on the number flux of soft photons available for cooling. Wolf-Rayet supernovae that explode through a thick wind have a high flux of soft photons, producing a flat spectrum, νF ν = Const, in the X-ray range of 0.1 ≲ T ≲ 50 keV. As the shock expands into an optically thin wind, the soft photons are no longer able to cool the shock that plows through the wind, and the bulk of the emission takes the form of a standard core-collapse supernova (without a wind). However, a small fraction of the soft photons is upscattered by the shocked wind and produces a transient unique X-ray signature.

  15. MRC5 and QU-DB bystander cells can produce bystander factors and induce radiation bystander effect

    Directory of Open Access Journals (Sweden)

    Mohammad Taghi Bahreyni Toossi

    2014-01-01

    Full Text Available Radiation damages initiated by radiation-induced bystander effect (RIBE are not limited to the first or immediate neighbors of the irradiated cells, but the effects have been observed in the cells far from the irradiation site. It has been postulated that bystander cells, by producing bystander factors, are actively involved in the propagation of bystander effect in the regions beyond the initial irradiated site. Current study was planned to test the hypothesis. MRC5 and QU-DB cell lines were irradiated, and successive medium transfer technique was performed to induce bystander effects in two bystander cell groups. Conditioned medium extracted from the target cells was transferred to the bystander cells (first bystander cells. After one hour, conditioned medium was substituted by fresh medium. Two hours later, the fresh medium was transferred to a second group of non-irradiated cells (second bystander cells. Micronucleated cells (MC were counted to quantify damages induced in the first and second bystander cell groups. Radiation effect was observed in the second bystander cells as well as in the first ones. Statistical analyses revealed that the number of MC in second bystander subgroups was significantly more than the corresponding value observed in control groups, but in most cases it was equal to the number of MC observed in the first bystander cells. MRC5 and QU-DB bystander cells can produce and release bystander signals in the culture medium and affect non-irradiated cells. Therefore, they may contribute to the RIBE propagation.

  16. Shock absorber

    International Nuclear Information System (INIS)

    Nemeth, J.D.

    1981-01-01

    A shock absorber for the support of piping and components in a nuclear power plant is described. It combines a high degree of stiffness under sudden shocks, e.g. seismic disturbances, with the ability to allow for thermal expansion without resistance when so required. (JIW)

  17. The RaDIATE High-Energy Proton Materials Irradiation Experiment at the Brookhaven Linac Isotope Producer Facility

    Energy Technology Data Exchange (ETDEWEB)

    Ammigan, Kavin; et al.

    2017-05-01

    The RaDIATE collaboration (Radiation Damage In Accelerator Target Environments) was founded in 2012 to bring together the high-energy accelerator target and nuclear materials communities to address the challenging issue of radiation damage effects in beam-intercepting materials. Success of current and future high intensity accelerator target facilities requires a fundamental understanding of these effects including measurement of materials property data. Toward this goal, the RaDIATE collaboration organized and carried out a materials irradiation run at the Brookhaven Linac Isotope Producer facility (BLIP). The experiment utilized a 181 MeV proton beam to irradiate several capsules, each containing many candidate material samples for various accelerator components. Materials included various grades/alloys of beryllium, graphite, silicon, iridium, titanium, TZM, CuCrZr, and aluminum. Attainable peak damage from an 8-week irradiation run ranges from 0.03 DPA (Be) to 7 DPA (Ir). Helium production is expected to range from 5 appm/DPA (Ir) to 3,000 appm/DPA (Be). The motivation, experimental parameters, as well as the post-irradiation examination plans of this experiment are described.

  18. Supersonic Ionization Wave Driven by Radiation Transport in a Short-Pulse Laser-Produced Plasma

    International Nuclear Information System (INIS)

    Ditmire, T.; Gumbrell, E.T.; Smith, R.A.; Mountford, L.; Hutchinson, M.H.

    1996-01-01

    Through the use of an ultrashort (2ps) optical probe, we have time resolved the propagation of an ionization wave into solid fused silica. This ionization wave results when a plasma is created by the intense irradiation of a solid target with a 2ps laser pulse. We find that the velocity of the ionization wave is consistent with radiation driven thermal transport, exceeding the velocity expected from simple electron thermal conduction by nearly an order of magnitude. copyright 1996 The American Physical Society

  19. Cooling of ions trapped in potential wells produced by electromagnetic radiation fields

    International Nuclear Information System (INIS)

    Sobehart, J.R.

    1990-01-01

    The probability distributions for the ground state and the excited state of a two-level ion trapped in an harmonic potential well are studied. The ion is excited by electromagnetic radiation and relaxes back due to either spontaneous or stimulated emission. The photon statistics is considered Poissonian and the momentum transfer between the electromagnetic field and the ion is assumed discrete. The present results are closely related to the quantum treatment in the heavy particle limit as well as to those derived from previous semiclassical models. (Author) [es

  20. Nuclear Exciton Echo Produced by Ultrasound in Forward Scattering of Synchrotron Radiation

    International Nuclear Information System (INIS)

    Smirnov, G.V.; van Buerck, U.; Arthur, J.; Popov, S.L.; Baron, A.Q.; Chumakov, A.I.; Ruby, S.L.; Potzel, W.; Brown, G.S.

    1996-01-01

    The time evolution of the coherent decay of a collective nuclear excitation (nuclear exciton), induced by 14.4 keV synchrotron radiation, was studied in a system of two stainless steel foils, where one was vibrated by ultrasound (US). The US vibrations disrupted the coherent nuclear emission from the two targets. However, at times corresponding to multiples of the US period, spike increases in the decay were observed. The spikes are interpreted as echoes of the initial nuclear exciton. copyright 1996 The American Physical Society

  1. Effect of mineral acid on polymer produced during radiation-induced grafting of styrene monomer

    International Nuclear Information System (INIS)

    Garnett, J.L.; Jankiewicz, S.V.; Sangster, D.F.

    1982-01-01

    The inclusion of mineral acid in a solution of styrene in methanol subjected to 60 Co γ irradiation markedly enhances the yield of monomer grafted to cellulose and other radiation grafting systems. Results were reported from a preliminary investigation into the mechanism of this acid effect through a study of the action of acid during the solution polymerization process. It was found that the presence of acid in a monomer solution such as styrene in 1, 4-dioxan led to an enhancement in the homopolymer yield of styrene; and it was showed that the acid also effected the number-average molecular weight of this homopolymer. 1 figure, 4 tables

  2. Electron beams by shock waves in the solar corona

    International Nuclear Information System (INIS)

    Mann, G.; Klassen, A.

    2005-07-01

    Beams of energetic electrons can be generated by shock waves in the solar corona. At the Sun shock waves are produced either by flares and/or by coronal mass ejections (CMEs). They can be observed as type II bursts in the solar radio radiation. Shock accelerated electron beams appear as rapidly drifting emission stripes (so-called ''herringbones'') in dynamic radio spectra of type II bursts. A large sample of type II bursts showing ''herringbones'' was statistically analysed with respect to their properties in dynamic radio spectra. The electron beams associated with the ''herringbones'' are considered to be generated by shock drift acceleration. Then, the accelerated electrons establish a shifted loss-cone distribution in the upstream region of the associated shock wave. Such a distribution causes plasma instabilities leading to the emission of radio waves observed as ''herringbones''. Consequences of a shifted loss-cone distribution of the shock accelerated electrons are discussed in comparison with the observations of ''herringbones'' within solar type II radio bursts. (orig.)

  3. Multinucleated Giant Cancer Cells Produced in Response to Ionizing Radiation Retain Viability and Replicate Their Genome

    Directory of Open Access Journals (Sweden)

    Razmik Mirzayans

    2017-02-01

    Full Text Available Loss of wild-type p53 function is widely accepted to be permissive for the development of multinucleated giant cells. However, whether therapy-induced multinucleation is associated with cancer cell death or survival remains controversial. Herein, we demonstrate that exposure of p53-deficient or p21WAF1 (p21-deficient solid tumor-derived cell lines to ionizing radiation (between 2 and 8 Gy results in the development of multinucleated giant cells that remain adherent to the culture dish for long times post-irradiation. Somewhat surprisingly, single-cell observations revealed that virtually all multinucleated giant cells that remain adherent for the duration of the experiments (up to three weeks post-irradiation retain viability and metabolize 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyl-tetrazolium bromide (MTT, and the majority (>60% exhibit DNA synthesis. We further report that treatment of multinucleated giant cells with pharmacological activators of apoptosis (e.g., sodium salicylate triggers their demise. Our observations reinforce the notion that radiation-induced multinucleation may reflect a survival mechanism for p53/p21-deficient cancer cells. With respect to evaluating radiosensitivity, our observations underscore the importance of single-cell experimental approaches (e.g., single-cell MTT as the creation of viable multinucleated giant cells complicates the interpretation of the experimental data obtained by commonly-used multi-well plate colorimetric assays.

  4. Observation of structure in the phi phi system produced in radiative J/psi decays

    International Nuclear Information System (INIS)

    Tripsas, B.

    1988-01-01

    A sample of 4.9 million J//psi/ decays from the Mark III detector at SPEAR is used to study the radiative decay J//psi/ → γ/phi//phi/. The decay is observed in two final states; γK + K/sup /minus//K + K/sup /minus// and the previously unobserved γK + K/sup /minus//K/sub S/ 0 K/sub L/ 0 . The new final state and an improved analysis of the all charged state allow the observation of a large enhancement in the /phi//phi/ mass spectrum in the region below 2.5 GeV/c 2 in addition to the /eta//sub c/. The product branching ratio B(J//psi/ → γ/eta//sub c/) /times/ B(/eta//sub c/ → /phi//phi/) is measured in both final states. The branching ratio to the low mass region, B(J//psi/ → γ/psi//psi/, m(/psi//psi/) 2 ) is also measured. The angular distribution of the kaons is used to demonstrate that the enhancement is predominantly pseudoscalar. This effect is similar to what is observed in other radiative decays to two vector mesons and a photon. An upper limit is placed on the production of tensor glueball candidates observed to decay to /psi//psi/ by another experiment. 41 figs., 110 figs., 10 tabs

  5. Changes of medullary hemopoiesis produced by chronic exposure to tritium oxide and external γ-radiation

    International Nuclear Information System (INIS)

    Murzina, L.D.; Muksinova, K.N.

    1982-01-01

    A comparative study of a chronic effect of tritium oxide ( 3 HOH) and external γ-radiation by 137 Cs on medullary hemopoiesis was conducted in experiments on Wistar rats. 3 HOH was administered for 3mos., 37x10 4 Bk per lg per of body mass daily (the absorbed dose 10.8 Gy), external irradiation was given in correlated values of dose rates and integral doses. Bone marrow depopulation was 1.9 times as deeper in rats exposed to 3 HOH as compared to that in irradiated rats. This difference is caused by early and stable inhibition of erythropoiesis with the administration of the radionuclide. The integral index showing the injuring effect of tritium on erythropoiesis was 4 times as high as compared to that of external γ-irradiation by 137 Cs. The time course of value of the proliferative pool of bone marrow granulocytes with the exposure to 2 types of radiation was monotypic. Differences in maturing and functioning granulocytic pools were marked in early time of the experiment

  6. Shielding required for radiation produced by 15 GeV stored electrons

    International Nuclear Information System (INIS)

    Jenkins, T.M.; McCaslin, J.B.; Thomas, R.H.

    1974-01-01

    The first phase of PEP will consist of a 15 GeV electron and positron storage ring. This note examines the shielding required by such a facility. Shielding of neutrons and muons produced by 200 GeV protons in the second phase of PEP has been discussed in previous notes. 9 refs., 9 figs., 5 tabs

  7. Gamma radiation and temperature influence on the chemical effect produced by isomeric transition in the telluric acid

    International Nuclear Information System (INIS)

    Muriel G, M.

    1976-01-01

    When the gamma radiation due to the isomeric transition is internally converted an autoionization is produced. For atoms with a high atomic number this autoionization can be a large one and produce a fragmentation in a molecule. In the specific case of the solid state these fragments remain trapped in different places of the crystalline system. This can be considered as chemical change in the original molecule. These damages produced by the nuclear transformation can be measured by different methods: heating, gamma rays, pressure, etc. In this work the results of an experimental measurement of the behavior of the crystalline telluric acid molecule fragments under gamma radiation (0 to 20 Mrads) with controlled temperature of 2 0 C (-196 0 C to 50 0 C) it is presented. It was observed that the values of the mentioned behavior vary rapidly at first for relatively low doses and that for larger doses these values remained constant. Besides with a lower temperature these variation are progressively lower. (author)

  8. HERSCHEL* FAR-INFRARED SPECTROSCOPY OF THE GALACTIC CENTER. HOT MOLECULAR GAS: SHOCKS VERSUS RADIATION NEAR Sgr A

    Energy Technology Data Exchange (ETDEWEB)

    Goicoechea, Javier R.; Etxaluze, M.; Cernicharo, J.; Bell, T. A. [Departamento de Astrofisica, Centro de Astrobiologia, CSIC-INTA, Carretera de Ajalvir, Km 4, Torrejon de Ardoz, E-28850 Madrid (Spain); Gerin, M.; De Luca, M.; Encrenaz, P. [LERMA, UMR 8112 du CNRS, Observatoire de Paris, Ecole Normale Superieure (France); Neufeld, D. A.; Indriolo, N. [Johns Hopkins University, Baltimore, MD 21218 (United States); Contursi, A. [Max-Planck-Institut fuer extraterrestrische Physik (MPE), Postfach 1312, D-85741 Garching (Germany); Lis, D. C. [California Institute of Technology, Pasadena, CA 91125 (United States); Polehampton, E. T. [RAL Space, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX (United Kingdom); Sonnentrucker, P., E-mail: jr.goicoechea@cab.inta-csic.es [Space Telescope Science Institute, Baltimore, MD 21218 (United States)

    2013-05-20

    We present a {approx}52-671 {mu}m spectral scan toward Sgr A* taken with the PACS and SPIRE spectrometers on board Herschel. The achieved angular resolution allows us to separate, for the first time at far-IR wavelengths, the emission toward the central cavity (gas in the inner central parsec of the galaxy) from that of the surrounding circumnuclear disk. The spectrum toward Sgr A* is dominated by strong [O III], [O I], [C II], [N III], [N II], and [C I] fine-structure lines (in decreasing order of luminosity) arising in gas irradiated by UV photons from the central stellar cluster. In addition, rotationally excited lines of {sup 12}CO (from J = 4-3 to 24-23), {sup 13}CO, H{sub 2}O, OH, H{sub 3}O{sup +}, HCO{sup +}, and HCN, as well as ground-state absorption lines of OH{sup +}, H{sub 2}O{sup +}, H{sub 3}O{sup +}, CH{sup +}, H{sub 2}O, OH, HF, CH, and NH are detected. The excitation of the {sup 12}CO ladder is consistent with a hot isothermal component at T{sub k} {approx_equal} 10{sup 3.1} K and n(H{sub 2}) {approx}< 10{sup 4} cm{sup -3}. It is also consistent with a distribution of temperature components at higher density with most CO at T{sub k} {approx}< 300 K. The detected molecular features suggest that, at present, neither very enhanced X-ray nor cosmic-ray fluxes play a dominant role in the heating of the hot molecular gas. The hot CO component (either the bulk of the CO column or just a small fraction depending on the above scenario) results from a combination of UV- and shock-driven heating. If irradiated dense clumps/clouds do not exist, shocks likely dominate the heating of the hot molecular gas. This is consistent with the high-velocity gas detected toward Sgr A*.

  9. Validation of Heat Shock Protein 70 as a Tumor-Specific Biomarker for Monitoring the Outcome of Radiation Therapy in Tumor Mouse Models

    Energy Technology Data Exchange (ETDEWEB)

    Bayer, Christine; Liebhardt, Michael E.; Schmid, Thomas E. [Department of Radiation Oncology, Klinikum rechts der Isar, Technische Universität München, Munich (Germany); Trajkovic-Arsic, Marija [II Medizinische Klinik, Klinikum rechts der Isar, Technische Universität München, Munich (Germany); Hube, Kathrin; Specht, Hanno M. [Department of Radiation Oncology, Klinikum rechts der Isar, Technische Universität München, Munich (Germany); Schilling, Daniela [Department of Radiation Oncology, Klinikum rechts der Isar, Technische Universität München, Munich (Germany); Clinical Kooperation Group, Innate Immunity in Tumor Biology, HelmholtzZentrum München, Munich (Germany); Gehrmann, Mathias; Stangl, Stefan [Department of Radiation Oncology, Klinikum rechts der Isar, Technische Universität München, Munich (Germany); Siveke, Jens T. [II Medizinische Klinik, Klinikum rechts der Isar, Technische Universität München, Munich (Germany); Wilkens, Jan J. [Department of Radiation Oncology, Klinikum rechts der Isar, Technische Universität München, Munich (Germany); Multhoff, Gabriele, E-mail: Gabriele.multhoff@lrz.tum.de [Department of Radiation Oncology, Klinikum rechts der Isar, Technische Universität München, Munich (Germany); Clinical Kooperation Group, Innate Immunity in Tumor Biology, HelmholtzZentrum München, Munich (Germany)

    2014-03-01

    Purpose: Tumor cells, in contrast to normal cells, frequently overexpress heat shock protein 70 (Hsp70) in the cytosol, present it on their cell surface, and actively release it. Therefore, soluble Hsp70 (sHsp70) was investigated as a potential tumor biomarker for monitoring the outcome of radiation therapy. Methods and Materials: Plasma from mice bearing membrane Hsp70 (mHsp70)-positive FaDu human squamous cell carcinoma of the head and neck and spontaneous pancreatic ductal adenocarcinoma (PDAC) was investigated. A cohort of mice with FaDu tumors (0.32 cm{sup 3}) was irradiated with 30 Gy, and plasma was collected 24 hours after irradiation, after the tumors had shrunk to 50% of their starting volume and after complete remission. sHsp70 levels in the plasma were quantified by enzyme-linked immunosorbent assay. Results: sHsp70 levels were significantly higher in the blood of tumor-bearing mice than that of control animals. A correlation between increasing sHsp70 plasma levels and tumor volume in the range of 0.01 cm{sup 3} to 0.66 cm{sup 3} was observed. Radiation-induced regression of the tumors was associated with significantly decreased sHsp70 levels, which returned to the level of control animals after complete remission. Conclusion: We propose sHsp70 as an innovative biomarker for detecting tumors and for monitoring the clinical outcome of radiation therapy in cancer patients.

  10. X-ray spectroscopic characterization of shock-ignition-relevant plasmas

    Czech Academy of Sciences Publication Activity Database

    Šmíd, Michal; Antonelli, L.; Renner, Oldřich

    2013-01-01

    Roč. 53, č. 2 (2013), 233-236 ISSN 1210-2709 R&D Projects: GA ČR GAP205/10/0814 Institutional support: RVO:68378271 Keywords : hot electrons * shock ignition * laser-produced plasma * X-ray spectroscopy * Kα radiation Subject RIV: BL - Plasma and Gas Discharge Physics

  11. demystifying the shock of shocking

    African Journals Online (AJOL)

    (with a pulse), atrial fibrillation and atrial flutter. The energy dose in cardioversion is less (0.5. - 2 J/kg) than in defibrillation (2 - 4 J/kg). In cardioversion the shock is discharged synchronously with the native R wave of the patient. Without synchronisation,. VF can be induced if a shock is delivered during the refractory period ...

  12. Effect of the methyl gallate on the damage produced by radiation in leucocytes of peripheral blood of In vivo mouse

    International Nuclear Information System (INIS)

    Zarco M, A.

    2007-01-01

    The ionizing radiation produces a great variety of lesions in the deoxyribonucleic acid (DNA) through the formation of free radicals (RL), reason why the study about those made up with possible radioprotective property has been increased. The methyl gallate (MeG) it is an antioxidant derived of plants with capacity to capture RL. The objective of the present work was to determine the effect of the methyl gallate on the damage in the DNA taken place by gamma radiation in leukocytes of peripheral blood of in vivo mouse. The experimental design consisted of 4 groups of mice: It has a witness of the solvent group, dimethylsulfoxide (DMSO), in which was administer by intraperitoneal via 0.4 mL of a solution 1:8 of DMSO: H 2 O; a second group, denominated MeG witness, it was administered intraperitoneally with a dose of 0.1 μ moles/g of weight. Another group was used as radiation witness, reason why it was only treated with 1 Gray (Gy) of gamma radiation coming from a cobalt 60 source. At last, the group denominated problem it was administered with 0.1 μ moles of MeG/g of corporal weight 30 previous minutes to the irradiation with 1 Gy. In the comparison of the damage and repair curves obtained with the unicellular in gel electrophoresis technique among the irradiated groups, it was determined that there is one significant reduction of 15% in the DNA damage observed to the two minutes postradiation in the problem group with respect to the radiation witness. It was concluded that this decrease is due to the antioxidant effect of the methyl gallate and that therefore this compound has possibilities to act as radioprotector. (Author)

  13. Study on radiation degradation of hydroxylamine derivatives. Pt.3: Qualitative and quantitative analyses of hydrogen and carbon monoxide produced by radiation degradation of N,N-diethyl hydroxylamine

    International Nuclear Information System (INIS)

    Wang Jinhua; Bao Borong; Wu Minghong; Sun Xilian

    2004-01-01

    The qualitative and quantitative analysis of hydrogen and carbon monoxide produced by radiation degradation of N,N-diethyl hydroxylamine is performed on a 2 m column packed with 5 Angstrom molecular sieve and equipped with a thermal conductivity detector. The analysis of hydrogen employs argon as a carrier gas, the column temperature is 85 degree C and the detector temperature is 110 degree C; the analysis of carbon monoxide employs hydrogen as a carrier gas, the column temperature is 50 degree C and the detector temperature is 80 degree C. The results show that the volume fraction of hydrogen is increased with the increase of dose, but has little relationship with the concentration of N,N-diethyl hydroxylamine. Carbon monoxide is only produced when the absorption dose is very high and the volume fraction is very low

  14. Effectiveness of radiation therapy for metastatic spinal tumors producing neurologic impairment

    International Nuclear Information System (INIS)

    Yamamoto, Shuichiro; Nomoto, Satoshi; Imada, Hajime; Nakata, Hajime

    2002-01-01

    The purpose of this study was to evaluate the efficacy of radiation therapy (RT) for treating neurological impairment and improving quality of life (QOL) in patients with metastatic spinal tumors. From 1985 through 2001, 75 patients with metastatic spinal tumors were treated with RT. Neurologic status and Karnofsky performance status were assessed before and after RT. The rate of neurologic improvement was significantly higher in patients with radio-sensitive tumors (75%) than in patients with radio-resistant tumors (37%). Few patients with Karnofsky performance status less than 40% before RT had good QOL after RT. The response to RT did not differ significantly on the basis of duration of paralysis before RT. RT is useful for treating neurologic impairment caused by metastatic spinal tumors, particularly those that are radiosensitive. To have good QOL after RT, treatment should be started in the early stage of neurological impairment. (author)

  15. Counter-radiation efficacy of Enoviton granules produced from Cabernet Sauvignon wine

    International Nuclear Information System (INIS)

    Fartzov, K.; Hadjiski, L.; Aljakov, M.

    1993-01-01

    Following the accident in the nuclear power station at Chernobyl, a need arose for radionuclide decontamination means capable of being used for a prolonged period of time without any side-effects on the human body. The probability of contamination with radionuclides in such emergencies, combined with external radiation, makes it necessary for the protective agents used to have a favourable effect on the protective force of the organism. The phenol compounds, anthocyanins, are the major plant pigments and are present in considerable amounts in red grapes and wines. Under relevant conditions in plants, phenolics protect hereditary cell mechanisms from mutagenic agents, such as ionising irradiation and UV rays. This ability of plant phenolics directed us towards the creation and use of the anthocyanin preparation Enoviton as a radioprotective means in investigations with animals. The Enoviton preparation was made on the basis of an anthocyanin colouring substance derived from specially isolated and purified anthocyanins from Cabernet Sauvignon wine. (Author)

  16. Counter-radiation efficacy of Enoviton granules produced from Cabernet Sauvignon wine

    Energy Technology Data Exchange (ETDEWEB)

    Fartzov, K. (National Wine Research and Control Inst., Sofia (Bulgaria)); Hadjiski, L.; Aljakov, M. (Sofia Medical Univ. (Bulgaria))

    1993-01-01

    Following the accident in the nuclear power station at Chernobyl, a need arose for radionuclide decontamination means capable of being used for a prolonged period of time without any side-effects on the human body. The probability of contamination with radionuclides in such emergencies, combined with external radiation, makes it necessary for the protective agents used to have a favourable effect on the protective force of the organism. The phenol compounds, anthocyanins, are the major plant pigments and are present in considerable amounts in red grapes and wines. Under relevant conditions in plants, phenolics protect hereditary cell mechanisms from mutagenic agents, such as ionising irradiation and UV rays. This ability of plant phenolics directed us towards the creation and use of the anthocyanin preparation Enoviton as a radioprotective means in investigations with animals. The Enoviton preparation was made on the basis of an anthocyanin colouring substance derived from specially isolated and purified anthocyanins from Cabernet Sauvignon wine. (Author).

  17. Adhesion of yeast cells on surface of polymers produced by radiation polymerization

    International Nuclear Information System (INIS)

    Lu, Zhaoxin; Takehisa, Masaaki; Xie Zongchuan.

    1995-01-01

    The adhesion of yeast (Saccharomyces formesences) cells on polymers was studied thermodynamically. The polymers were laminally prepared by means of radiation polymerization. By measuring contact angles, we calculated dispersion component and polar component of surface free energy of the polymers and the cells, and interfacial free energy between the polymer and the cells. Then interfacial free energy change of the cell adhesion to surface of the polymer was evaluated. The adhesion behavior of yeast cells on the polymers was observed by optical microscope. From above results, we conclude that the initial adhesion of the cells is related to the surface free energy of the polymer, but the irreversible adhesion may be close to the polar component in surface free energy. The high polar component is favourable the irreversible adhesion of yeast cells. (author)

  18. A study of ethanol production of yeast cells immobilized with polymer carrier produced by radiation polymerization

    International Nuclear Information System (INIS)

    Lu Zhaoxin; Fujimura, Takashi

    1993-01-01

    Polymer carriers, poly(hydroxyethyl acrylate(HEA)-methoxy polyethylene glycol methylacrylate (M-23G)) and poly(hydroxyethyl acrylate(HEA)-glycidyl methylacrylate (GMA)) used for the immobilization of yeast cells were prepared by radiation polymerization at low temperature. Yeast cells were immobilized through adhesion and multiplication of yeast cells. The ethanol productivity of immobilized yeast cells with these carriers was related to the monomer composition of polymers and the optimum monomer composition was 20%:10% in poly(HEA-M-23G) and 17%:6% in poly(HEA-GMA). In this case, the ethanol productivity of immobilized yeast cells was about 4 times that of cells in free system. The relationship between the activity of immobilized yeast cells and the water content of the polymer carrier were also discussed. (author)

  19. Effect of gamma ray radiation pretreatment on enzymatic hydrolysis of wheat straw to produce sugar

    International Nuclear Information System (INIS)

    Yang Chunping; Shen Zhiqiang; Yu Guoce; Wang Jianlong

    2009-01-01

    The effect and aftereffect of radiation pretreatment of wheat straw with gamma ray were studied. It is shown that irradiation can cause significant breakdown of the structure of wheat straw. The mass loss of wheat straw increases and the size distribution after crushing moves to fine particles at elevated irradiation doses. A synergistic effect between irradiation and crushing was observed, with a glucose yield of 10.2% at a dose of 500 kGy with powder of 0.109 mm. The aftereffect of irradiation has important impact on enzymatic hydrolysis of wheat straw. The aftereffect of 400 kGy irradiation accounts for 20.1% of the initial effect for glucose production, and the aftereffects of 50, 100, 200 and 300 kGy account for 12.9%, 14.9%, 8.9% and 9.1%, respectively, for reducing sugar production. (authors)

  20. Start broadened profiles with self-consistent radiation transfer and atomic kinetics in plasmas produced by high intensity lasers

    International Nuclear Information System (INIS)

    Olson, G.L.; Comly, J.C.; La Gattuta, J.K.; Kilcrease, D.P.

    1993-01-01

    Spectral line shapes and line strengths have long been used to diagnose plasma temperatures and densities. In dense plasmas, the additional broadening due to Stark effects give additional information about the plasma density. We present calculations that are self-consistent in that the radiation fields of the line transitions and the atomic kinetics are iterated to convergence. Examples are given for simple plasmas with temperature gradients, density gradients, and velocity fields. Then a more complex example of a laser produced plasma is presented

  1. Energetic ion acceleration at collisionless shocks

    Science.gov (United States)

    Decker, R. B.; Vlahos, L.

    1985-01-01

    An example is presented from a test particle simulation designed to study ion acceleration at oblique turbulent shocks. For conditions appropriate at interplanetary shocks near 1 AU, it is found that a shock with theta sub B n = 60 deg is capable of producing an energy spectrum extending from 10 keV to approx. 1 MeV in approx 1 hour. In this case total energy gains result primarily from several separate episodes of shock drift acceleration, each of which occurs when particles are scattered back to the shock by magnetic fluctuations in the shock vicinity.

  2. Energetic ion acceleration at collisionless shocks

    International Nuclear Information System (INIS)

    Decker, R.B.; Vlahos, L.

    1985-01-01

    An example is presented from a test particle simulation designed to study ion acceleration at oblique turbulent shocks. For conditions appropriate at interplanetary shocks near 1 AU, it is found that a shock with theta sub B n = 60 deg is capable of producing an energy spectrum extending from 10 keV to approx 1 MeV in approx 1 hour. In this case total energy gains result primarily from several separate episodes of shock drift acceleration, each of which occurs when particles are scattered back to the shock by magnetic fluctuations in the shock vicinity

  3. Thermoluminescence of annealed and shock-loaded feldspar

    International Nuclear Information System (INIS)

    Hartmetz, C.P.

    1988-01-01

    Samples of oligoclase and bytownite were shock-loaded to a variety of pressures, and annealed for a variety of temperatures and times. The effect of Mrad doses of gamma-rays on oligoclase TL were also studied. After these treatments, thermoluminescence (TL) and X-ray diffraction (XRD) measurements were made to: (1) determine the effects of shock on terrestrial feldspar and compare with variations in the TL emission of ordinary chondrites (OCs); (2) determine if disordering in feldspar was responsible for any related changes in TL properties of OCs; (3) determine if the combined effect of shock plus annealing causes the changes in TL properties; (4) see if radiation damage from cosmic ray exposure plays a role in the TL variations; (5) examine the implications of this work to the thermal and shock histories of OCs. The lightly shock-loaded and annealed oligoclase samples have a dominant peak temperature of 120-140 C, identical to type 3.3-3.5 OCs. The heavily shocked samples dominant peak is at 230C, similar to type > 3.5 OCs . While the heavily annealed/disordered oligoclase samples have a peak at 280C, this peak is rarely observed in OCs. Radiation damage from Mrad doses of gamma-rays produced no change in peak temperature, but facilitated the shift to higher peak temperatures. The TL sensitivity of the shocked samples decreased by a factor of 25. Samples annealed at low temperatures (438-533C) showed a factor of 2 decrease in TL, but at the highest temperatures, the TL was a factor of 8 higher

  4. Shock-induced synthesis of high temperature superconducting materials

    Science.gov (United States)

    Ginley, D.S.; Graham, R.A.; Morosin, B.; Venturini, E.L.

    1987-06-18

    It has now been determined that the unique features of the high pressure shock method, especially the shock-induced chemical synthesis technique, are fully applicable to high temperature superconducting materials. Extraordinarily high yields are achievable in accordance with this invention, e.g., generally in the range from about 20% to about 99%, often in the range from about 50% to about 90%, lower and higher yields, of course, also being possible. The method of this invention involves the application of a controlled high pressure shock compression pulse which can be produced in any conventional manner, e.g., by detonation of a high explosive material, the impact of a high speed projectile or the effect of intense pulsed radiation sources such as lasers or electron beams. Examples and a discussion are presented.

  5. Degradation of Dextran Produced by Leuconostoc mesenteroides ATCC 13146 using Electron Beam Radiation

    International Nuclear Information System (INIS)

    Hong, Jun Tack; Yoo, Sun Kyun; Kang, Hyun Suk; Lee, Byung Cheol

    2010-01-01

    Dextrans make up a family of glucans that have contiguous alpha-1.6 glucose linkages. Differences in the different dextrans in volve the types, amount, length, and arrangements of the arrangements of the branch chains. The principle type of branch linkages found are alpha-1.3, but alpha-1.2 and-1.4 branch linkages have been also observed. In recent days. dextrans have been investigated as potential macromolecular carriers for delivery of drugs and proteins, primarily to increase the longeveity of therapeutic agents in the circulation. In most previous researches, linear type of dextrans with molecular weigh of Μ w 10,000 to 100,000 have been applied for development of new type of drug delivery agent. Such a size of dextrans have been manufactured by acid hydrolysis, of which processes are multi-steps and time-consumed. Therefore, this objective of this research is to evaluate the characterization of branched degraded by a electron beam radiation. L. mesenteroides ATCC 13146 was cultured on te agar slant medium with the composition of 3.0 g K 2 HPO 4 , 0.01 g FeSO 4 . H 2 O, 0.01 g MnSO 4 . 7H 2 O, 0.01 g NaCl, 0.05 g CaCl 2 , 0.5g yeast extract, 15 g agar and 30 g sucrose per liter deionized water. Medium pH was adjusted to 6.0 prior to sterilization. Dextran production was conducted in a fermentor a working volume of 5 1 by using 18% sucrose under optimum pH condition. The inoculum was 2% of the working volume. Fermentation conditions are 28 C, 100 rpm agitation, and 1 vvm of aeration. The fermentation process continued until sucrose was consumed completely. The branch degree of dextran was evaluated using dextranase and analyzed by TLC. The air-dry dextran and solution dextran was irradiated at room temperature using a electrostatic accelerator. The irradiation doses ranged between 30 kGy to 80 kGy. After irradiation, processed dextran showed still a large of branched form. The degradation degree was increased as radiation intensity. The average molecular weight

  6. Radiation damage and thermal shock response of carbon-fiber-reinforced materials to intense high-energy proton beams

    Directory of Open Access Journals (Sweden)

    N. Simos

    2016-11-01

    Full Text Available A comprehensive study on the effects of energetic protons on carbon-fiber composites and compounds under consideration for use as low-Z pion production targets in future high-power accelerators and low-impedance collimating elements for intercepting TeV-level protons at the Large Hadron Collider has been undertaken addressing two key areas, namely, thermal shock absorption and resistance to irradiation damage. Carbon-fiber composites of various fiber weaves have been widely used in aerospace industries due to their unique combination of high temperature stability, low density, and high strength. The performance of carbon-carbon composites and compounds under intense proton beams and long-term irradiation have been studied in a series of experiments and compared with the performance of graphite. The 24-GeV proton beam experiments confirmed the inherent ability of a 3D C/C fiber composite to withstand a thermal shock. A series of irradiation damage campaigns explored the response of different C/C structures as a function of the proton fluence and irradiating environment. Radiolytic oxidation resulting from the interaction of oxygen molecules, the result of beam-induced radiolysis encountered during some of the irradiation campaigns, with carbon atoms during irradiation with the presence of a water coolant emerged as a dominant contributor to the observed structural integrity loss at proton fluences ≥5×10^{20}  p/cm^{2}. The carbon-fiber composites were shown to exhibit significant anisotropy in their dimensional stability driven by the fiber weave and the microstructural behavior of the fiber and carbon matrix accompanied by the presence of manufacturing porosity and defects. Carbon-fiber-reinforced molybdenum-graphite compounds (MoGRCF selected for their impedance properties in the Large Hadron Collider beam collimation exhibited significant decrease in postirradiation load-displacement behavior even after low dose levels (∼5×10^{18}

  7. Innovative Approaches to Enhance Safety and Radiation Protection on a PET RI/RF Producing Facility for Occupationally Exposed Personnel

    International Nuclear Information System (INIS)

    Avila-Sobarzo, M.J.; Tenreiro, C.; Sadeghi, M.

    2011-01-01

    The explosive demand for positron emission tomography (PET) and, recently introduced, fusion technology (PET/CT and soon commercially available PET/MRI) as non-invasive diagnostic tools of choice for clinical imaging, results on a world wide PET centers and PET RI/RF production facilities remarkably increment . A charged particle accelerator when operated for PET radionuclides production produces ionizing radiation. The multi curies radionuclides from the accelerator and the radiopharmaceuticals synthesized are ionizing radiations emitters open sources. Therefore, the probability of unexpected radiation exposure is always present along full production line, from target loading for irradiation to final dose dispensing.Improving safety working conditions requires permanent radiological risks assessment associated with the production process for accelerator operators, radio chemist and hot cell assistants as well as other occupationally exposed personnel.In this work we present some of the experimental improvements added to our Cyclone 18/9 operation and routinely 18 FDG production process to improve personnel radioprotection. These approaches apply for professionals working on other accelerator field such as non-destructive analytical and tracer technicians at research and industrial levels with charged particle accelerators

  8. Electromagnetic radiation emitted by a plasma produced in air by laser pulses with lambda = 10.6 μm

    International Nuclear Information System (INIS)

    Danilychev, V.A.; Zvorykin, V.D.; Kholin, I.V.; Chugunov, A.Y.

    1981-01-01

    The spectrum, brightness, and energy have been measured for the electromagnetic radiation emitted by a plasma produced in air near a solid surface by pulses from a high-power CO 2 laser. The air pressure was varied over the range p 0 = 0.1--760 torr, and the laser power density was varied over the range q = 5 x 10 6 --10 8 W/cm 2 . At p 0 > or approx. =2--5 torr the radiation properties of the plasma are determined by a laser-beam absorption wave which arises in the gas. The maximum brightness temperature, T/sub b/approx. =50 000 K (lambda = 400 +- 20 nm), is reached at p 0 = 25 torr. The emission spectrum is quite different from an equilibrium spectrum, consisting primarily of NII, OII, and NIII lines. The total energy radiation by the plasma in the wavelength interval 360--2600 nm into a solid angle of 4π sr reaches 2.3% of the laser pulse energy

  9. Application of radiation processing to produce biotic elicitor for sugarcane in Vietnam

    International Nuclear Information System (INIS)

    Nguyen, Quoc Hien; Tran, Tich Canh; Truong, Thi Hanh; Vo, Thi Kim Lang; Dang, Van Phu; Cao, Anh Duong

    2007-01-01

    Sugarcane is the main raw material for production of sugar and ethanol. In Vietnam, it was reported in 1998 that the area for sugarcane growth was about 257,000ha. Up to now, the biotic elicitor, oligosaccharide has not been used for sugarcane yet. This study has been carried out to investigate the elicitation and the growth promotion effect of irradiated chitosan (oligochitosan) for sugarcane. The field test results indicated that alpha chitosan (shrimp shell) and beta chitosan (squid pen) samples with the content of water soluble oligomer of about 70% were the most effective. The disease ratio of sugarcane tree-trunk treated with irradiated chitosan before harvesting time decreased to 30-40% compared to non-treated one (100%). In addition, the productivity of sugarcane increased to about 20%. The combination of metal ion (Zn ++ , Cu ++ ) with oligochitosan did not show the synergic elicitation effect. The results revealed that biotic elicitor made from chitosan by radiation degradation method is very promising for field application not only for protection of disease infection but also for growth promotion of plants. It is believed that this biotic elicitor could be largely used for safe and sustainable development of agriculture. (author)

  10. Detection of ochratoxin produced by A. ochraceus in feedstuffs and its control by {gamma} radiation

    Energy Technology Data Exchange (ETDEWEB)

    Refai, M.K. [Cairo Univ. (Egypt). Dept. of Veterinary Medicine; Aziz, N.H.; El-Far, F. [National Centre for Radiation Research and Technology, Cairo (Egypt); Hassan, A.A. [Animal Health Research Inst., Dokki, Cairo (Egypt)

    1996-07-01

    {gamma}-Irradiation has been proposed as a means of food preservation and as an appropriate process for decontamination of toxigenic moulds in animal feeds prior to their production of mycotoxins. The investigation of 295 samples of livestock feedstuffs revealed that Aspergillus ochraceus occurs with high incidence in straw samples (90%), in 40-60% of hay, cotton-seed cake, and rice samples and in 10-30% of wheat, yellow corn, barley, broiler`s concentrates, kidney beans and tibn samples. Ochratoxin A was detected in 98 of 295 samples of stored feedstuffs at levels ranging from 700 to 8000 ppb. At a radiation dose 4 kGy, the growth of A. ochraceus and the subsequent ochratoxin production in poultry feed concentrates were completely inhibited. A dose of 15 or 20 kGy was sufficient for complete destruction of ochratoxin in yellow corn and soyabean. A dose of 20 kGy, however, controlled the occurrence of ochratoxin in poultry layer`s concentrates, broiler`s concentrates and cotton-seed cake by only 40, 47 and 36%, respectively. (author).

  11. Detection of ochratoxin produced by A. ochraceus in feedstuffs and its control by γ radiation

    International Nuclear Information System (INIS)

    Refai, M.K.; Hassan, A.A.

    1996-01-01

    γ-Irradiation has been proposed as a means of food preservation and as an appropriate process for decontamination of toxigenic moulds in animal feeds prior to their production of mycotoxins. The investigation of 295 samples of livestock feedstuffs revealed that Aspergillus ochraceus occurs with high incidence in straw samples (90%), in 40-60% of hay, cotton-seed cake, and rice samples and in 10-30% of wheat, yellow corn, barley, broiler's concentrates, kidney beans and tibn samples. Ochratoxin A was detected in 98 of 295 samples of stored feedstuffs at levels ranging from 700 to 8000 ppb. At a radiation dose 4 kGy, the growth of A. ochraceus and the subsequent ochratoxin production in poultry feed concentrates were completely inhibited. A dose of 15 or 20 kGy was sufficient for complete destruction of ochratoxin in yellow corn and soyabean. A dose of 20 kGy, however, controlled the occurrence of ochratoxin in poultry layer's concentrates, broiler's concentrates and cotton-seed cake by only 40, 47 and 36%, respectively. (author)

  12. Hypovolemic shock

    Science.gov (United States)

    ... the person's position unless they are in immediate danger. Do not give fluids by mouth. If person ... the patient with shock. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine . 25th ed. Philadelphia, PA: ...

  13. Stimulation of murine stem cell proliferation by circulating activities produced during the recovery of a radiation-induced hemopoietic injury

    International Nuclear Information System (INIS)

    Grande Azanedo, M.T.

    1988-01-01

    The proliferative activity of CFU-S, low in normal steady state, increases after treatment with different aggressors, i.e. radiation. This stimulation has been attributed in part to a local regulation system of stem cell proliferation, and at least in part to a humoral regulatory system. In the present work it has been investigated the role that circulating activities have in the CFU- S stimulation, by means of in vitro and in vivo incubation assays with diffusion chambers. The results show that bone marrow of mice irradiated with 5 Gy produces in vitro diffusible activities capable of stimulating the CFU-S proliferation. As well with this same dose circulating activities are also produced in vivo. In addition we have observed that these activities are only released during the periods of active hemopoietic regeneration that follow irradiation with moderate doses (1.5 and 5 Gy). In another set of experiments we saw that the stimulating activities are also detected in serum of mice irradiated with 5 Gy. These serum activities modify the proliferative state of very primitive precursors (12 d CFU-S). When the serum activities are added to long term bone marrow cultures the CFU-S) are also stimulated to proliferate. Finally, we observed that the radiation-induced serum activities stimulate the proliferation of bone marrow CFU-S when injected into normal mice, suggesting that such activities are involved in the regulation of CFU-S proliferation. (Author)

  14. Electric Shock Injuries in Children

    Science.gov (United States)

    ... Issues Listen Español Text Size Email Print Share Electric Shock Injuries in Children Page Content ​When the ... comes into direct contact with a source of electricity, the current passes through it, producing what's called ...

  15. Shock absorber

    International Nuclear Information System (INIS)

    Housman, J.J.

    1978-01-01

    A shock absorber is described for use in a hostile environment at the end of a blind passage for absorbing impact loads. The shock absorber includes at least one element which occupies the passage and which is comprised of a porous brittle material which is substantially non-degradable in the hostile environment. A void volume is provided in the element to enable the element to absorb a predetermined level of energy upon being crushed due to impact loading

  16. BOW SHOCK FRAGMENTATION DRIVEN BY A THERMAL INSTABILITY IN LABORATORY ASTROPHYSICS EXPERIMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki-Vidal, F.; Lebedev, S. V.; Pickworth, L. A.; Swadling, G. F.; Skidmore, J.; Hall, G. N.; Bennett, M.; Bland, S. N.; Burdiak, G.; De Grouchy, P.; Music, J.; Suttle, L. [Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BW (United Kingdom); Ciardi, A. [Sorbonne Universités, UPMC Univ. Paris 6, UMR 8112, LERMA, F-75005, Paris (France); Rodriguez, R.; Gil, J. M.; Espinosa, G. [Departamento de Fisica de la Universidad de Las Palmas de Gran Canaria, E-35017 Las Palmas de Gran Canaria (Spain); Hartigan, P. [Department of Physics and Astronomy, Rice University, 6100 S. Main, Houston, TX 77521-1892 (United States); Hansen, E.; Frank, A., E-mail: f.suzuki@imperial.ac.uk [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States)

    2015-12-20

    The role of radiative cooling during the evolution of a bow shock was studied in laboratory-astrophysics experiments that are scalable to bow shocks present in jets from young stellar objects. The laboratory bow shock is formed during the collision of two counterstreaming, supersonic plasma jets produced by an opposing pair of radial foil Z-pinches driven by the current pulse from the MAGPIE pulsed-power generator. The jets have different flow velocities in the laboratory frame, and the experiments are driven over many times the characteristic cooling timescale. The initially smooth bow shock rapidly develops small-scale nonuniformities over temporal and spatial scales that are consistent with a thermal instability triggered by strong radiative cooling in the shock. The growth of these perturbations eventually results in a global fragmentation of the bow shock front. The formation of a thermal instability is supported by analysis of the plasma cooling function calculated for the experimental conditions with the radiative packages ABAKO/RAPCAL.

  17. Bone marrow stromal cells spontaneously produce Flt3-ligand: influence of ionizing radiations and cytokine stimulation.

    Science.gov (United States)

    Bertho, Jean Marc; Demarquay, Christelle; Mouiseddine, Moubarak; Douenat, Noémie; Stefani, Johanna; Prat, Marie; Paquet, François

    2008-08-01

    To define the ability of human bone marrow (BM) stromal cells to produce fms-like tyrosine kinase 3 (Flt3)-ligand (FL), and the effect of irradiation, tumour necrosis factor-alpha (TNFalpha) or tumour growth factor beta (TGFbeta) on FL production. Primary BM stromal cell cultures were irradiated at 2-10 Gy or were stimulated with TNFalpha or TGFbeta1. The presence of FL was tested in culture supernatants and in cell lysate. The presence of a membrane-bound form of FL and the level of gene expression were also tested. Primary BM stromal cells spontaneously released FL. This production was increased by TNFalpha but not by TGFbeta1 or by irradiation. Chemical induction of osteoblastic differentiation from BM stromal cells also induced an increase in FL release. Our results suggest that the observed increase in FL concentration after in vivo irradiation is an indirect effect. The possible implication of BM stromal cells in these mechanisms is discussed.

  18. Monte Carlo method for calculating the radiation skyshine produced by electron accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Kong Chaocheng [Department of Engineering Physics, Tsinghua University Beijing 100084 (China)]. E-mail: kongchaocheng@tsinghua.org.cn; Li Quanfeng [Department of Engineering Physics, Tsinghua University Beijing 100084 (China); Chen Huaibi [Department of Engineering Physics, Tsinghua University Beijing 100084 (China); Du Taibin [Department of Engineering Physics, Tsinghua University Beijing 100084 (China); Cheng Cheng [Department of Engineering Physics, Tsinghua University Beijing 100084 (China); Tang Chuanxiang [Department of Engineering Physics, Tsinghua University Beijing 100084 (China); Zhu Li [Laboratory of Radiation and Environmental Protection, Tsinghua University, Beijing 100084 (China); Zhang Hui [Laboratory of Radiation and Environmental Protection, Tsinghua University, Beijing 100084 (China); Pei Zhigang [Laboratory of Radiation and Environmental Protection, Tsinghua University, Beijing 100084 (China); Ming Shenjin [Laboratory of Radiation and Environmental Protection, Tsinghua University, Beijing 100084 (China)

    2005-06-01

    Using the MCNP4C Monte Carlo code, the X-ray skyshine produced by 9 MeV, 15 MeV and 21 MeV electron linear accelerators were calculated respectively with a new two-step method combined with the split and roulette variance reduction technique. Results of the Monte Carlo simulation, the empirical formulas used for skyshine calculation and the dose measurements were analyzed and compared. In conclusion, the skyshine dose measurements agreed reasonably with the results computed by the Monte Carlo method, but deviated from computational results given by empirical formulas. The effect on skyshine dose caused by different structures of accelerator head is also discussed in this paper.

  19. Determination of volatiles produced during radiation processing in food and medicinal herbs

    International Nuclear Information System (INIS)

    Salum, Debora Christina

    2008-01-01

    In order to protect food from pathogenic microorganisms as well as to increase its shelf life while keeping sensorial properties (e.g. odor and taste), once the latter are one of the main properties required by spice buyers, it is necessary to analyze volatile formation from irradiation of medicinal and food herbs. The aim of the present study was to analyze volatile formation from Co irradiation of Laurus Cinnamomum, Piper Nigrum, Origanum Vulgare and Myristica Fragans. Possible changes on the odor of these herbs are evaluated by characterizing different radiation doses and effects on sensorial properties in order to allow better application of irradiation technology. l he samples have been irradiated in plastic packages by making use of a 60 Co Gamma irradiator. Irradiation doses of 0, 5, 10, 15, 20 and 25kGy have been tested. For the analysis of the samples, SPME has been applied, while for the analysis of volatile compounds, CG/MS. Spice irradiation has promoted mostly decrease in volatile compounds when doses of 5, 10, 15, 20 and 25kGy were used. For Laurus cinnamomum, the irradiation decreased volatile by nearly 56% and 89.5% respectively, comparing to volatile from a sample which has not been previously irradiated. Differently from other spices analyzed, irradiation on Myristica Fragans has increased volatile compounds except for 4-terpineol. The miristicine (toxic substance when in large quantities, commonly mentioned as narcotic) has increased by nearly 80%. For Origanum Vulgare and Piper Nigrum, significant decrease in volatile compounds have been found, mainly when it comes to 25 kGy irradiation. In general, results indicate loss of sensorial quality of spices. (author)

  20. Generation of EM radiations using intense electron beam produced in vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Shukla, R.; Shyam, A.; Verma, R.; Deb, P.; Mishra, E.; Meena, M., E-mail: rshukla@barc.gov.in [Energetics and Electromagnetics Division, Bhabha Atomic Research Centre Facility, Visakhapatnam (India)

    2014-07-01

    The results of a pulse power generator driving an axial virtual cathode oscillator are being presented in this paper as a source of high power microwave (HPM) radiations. The electron beam generator is also modified to attain the intense X-ray burst. The pulse power generator used for these applications is common and is having 10 ohms as its characteristic impedance with 50nS of pulse width. The peak charging voltage of the pulse forming line is 450 kV and hence 225 kV and 22.5 kA is peak voltage and peak current delivery capabilities respectively for the pulse power generator. The peak electrical power of the generator is 5GW for a matched load. The charging power supply for the pulse forming line consists of a high voltage generator made by pulse transformer and charging the pulse forming line in the first cycle of the charging pulse. To utilize the energy of the primary capacitive storage efficiently the pulse transformer is having 0.8 coupling coefficient between its primary and the secondary. The axial vircator chamber is evacuated to attain the vacuum of 2 x 10{sup -4} torr for the HPM application. In the case of modified electron beam chamber for the generation of X-rays the vacuum of same order is used. The pulse forming line is made using equal lengths of high voltage transmission lines, each having a length of 10 meters, connected in the parallel to give a net source impedance of 10 ohm. The pulse power generator can operate in repetitive mode and hence the HPM as well as X-rays may be generated in the repetitive burst. (author)

  1. Simulations of Converging Shock Collisions for Shock Ignition

    Science.gov (United States)

    Sauppe, Joshua; Dodd, Evan; Loomis, Eric

    2016-10-01

    Shock ignition (SI) has been proposed as an alternative to achieving high gain in inertial confinement fusion (ICF) targets. A central hot spot below the ignition threshold is created by an initial compression pulse, and a second laser pulse drives a strong converging shock into the fuel. The collision between the rebounding shock from the compression pulse and the converging shock results in amplification of the converging shock and increases the hot spot pressure above the ignition threshold. We investigate shock collision in SI drive schemes for cylindrical targets with a polystyrene foam interior using radiation-hydrodynamics simulations with the RAGE code. The configuration is similar to previous targets fielded on the Omega laser. The CH interior results in a lower convergence ratio and the cylindrical geometry facilitates visualization of the shock transit using an axial X-ray backlighter, both of which are important for comparison to potential experimental measurements. One-dimensional simulations are used to determine shock timing, and the effects of low mode asymmetries in 2D computations are also quantified. LA-UR-16-24773.

  2. THE EVOLUTION OF MOLECULAR LINE PROFILES INDUCED BY THE PROPAGATION OF C-SHOCK WAVES

    International Nuclear Information System (INIS)

    Jimenez-Serra, I.; Caselli, P.; Martin-Pintado, J.; RodrIguez-Franco, A.; Viti, S.

    2009-01-01

    We present the first results of the expected variations of the molecular line emission arising from material recently affected by C-shocks (shock precursors). Our parametric model of the structure of C-shocks has been coupled with a radiative transfer code to calculate the molecular excitation and line profiles of shock tracers such as SiO, and of ion and neutral molecules such as H 13 CO + and HN 13 C, as the shock propagates through the unperturbed medium. Our results show that the SiO emission arising from the early stage of the magnetic precursor typically has very narrow line profiles slightly shifted in velocity with respect to the ambient cloud. This narrow emission is generated in the region where the bulk of the ion fluid has already slipped to larger velocities in the precursor as observed toward the young L1448-mm outflow. This strongly suggests that the detection of narrow SiO emission, and of an ion enhancement in young shocks, is produced by the magnetic precursor of C-shocks. In addition, our model shows that the different velocity components observed toward this outflow can be explained by the coexistence of different shocks at different evolutionary stages, within the same beam of the single-dish observations.

  3. State of the art extracorporeal shock wave lithotripsy

    Energy Technology Data Exchange (ETDEWEB)

    Kandel, L.B. (State Univ. of New York at Stony Brook, Stony Brook, NY (US)); Harrison, L.H.; McCullough, D.L. (Wake Forest Univ. Medical Center, Winston-Salem, NC (US))

    1987-01-01

    This book contains 16 chapters. Some of the topics that are covered are: Extracorporeal Shock Wave Lithotripsy Development; Laser-Generated Extracorporeal Shock Wave Lithotripter; Radiation Exposure during ESWL; Caliceal Calculi; and Pediatric ESWL.

  4. State of the art extracorporeal shock wave lithotripsy

    International Nuclear Information System (INIS)

    Kandel, L.B.; Harrison, L.H.; McCullough, D.L.

    1987-01-01

    This book contains 16 chapters. Some of the topics that are covered are: Extracorporeal Shock Wave Lithotripsy Development; Laser-Generated Extracorporeal Shock Wave Lithotripter; Radiation Exposure during ESWL; Caliceal Calculi; and Pediatric ESWL

  5. Shocks in the Early Universe.

    Science.gov (United States)

    Pen, Ue-Li; Turok, Neil

    2016-09-23

    We point out a surprising consequence of the usually assumed initial conditions for cosmological perturbations. Namely, a spectrum of Gaussian, linear, adiabatic, scalar, growing mode perturbations not only creates acoustic oscillations of the kind observed on very large scales today, it also leads to the production of shocks in the radiation fluid of the very early Universe. Shocks cause departures from local thermal equilibrium as well as create vorticity and gravitational waves. For a scale-invariant spectrum and standard model physics, shocks form for temperatures 1  GeVUniverse as early as 10^{-30}  sec after the big bang.

  6. Simulation of mechanical shock environments

    International Nuclear Information System (INIS)

    Lalanne, Christian.

    1975-07-01

    Shocks can produce a severe mechanical environment which must be taken into account when designing and developing new equipments. After some mathematical (Laplace and Fourier transforms) and mechanical recalls (response of a one degree freedom system to a sinusoidal excitation), different analysis methods are compared, these methods being the most used now to compare relative severities of tests and establish specifications. A few chapter deal with the different properties of simple, easy to produce, shock shapes. Then some now-in-use programmators or shock-machines specifications are shown. A final chapter concerns acceleration transducers [fr

  7. The flying radiation case

    International Nuclear Information System (INIS)

    Brownell, J.H.; Bowers, R.L.

    1997-01-01

    The Los Alamos foil implosion program has the goal of producing an intense, high-energy density x-ray source by converting the energy of a magnetically imploded plasma into radiation and material energy. One of the methods for converting the plasma energy into thermal energy and radiation and utilizing it for experiments is called the flying radiation case (FRC). In this paper the authors shall model the FRC and provide a physical description of the processes involved. An analytic model of a planar FRC in the hydrodynamic approximation is used to describe the assembly and shock heating of a central cushion by a conducting liner driver. The results are also used to benchmark a hydrodynamics code for modeling an FRC. They then use a radiation-hydrodynamics computational model to explore the effects of radiation production and transport when a gold plasma assembles on a CH cushion. Results are presented for the structure and evolution of the radiation hohlraum

  8. Noble gas studies in vapor-growth diamonds: Comparison with shock-produced diamonds and the origin of diamonds in ureilites

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, Junichi; Fukunaga, Kazuya; Ito, Keisuke (Kobe Univ. (Japan))

    1991-07-01

    The authors synthesized vapor-trowth diamonds by two kinds of Chemical Vapor Deposition (CVD) using microwave (MWCVD) and hot filament (HFCVD) ionization of gases, and examined elemental abundances and isotopic compositions of the noble gases trapped in the diamonds. It is remarkable that strong differences existed in the noble gas concentrations in the two kinds of CVD diamonds: large amounts of noble gases were trapped in the MWCVD diamonds, but not in the HFCVD diamonds. The heavy noble gases (Ar to Xe) in the MWCVD diamonds were highly fractionated compared with those in the ambient atmosphere, and are in good agreement with the calculated fractionation patterns for plasma at an electron temperature of 7,000-9,000 K. These results strongly suggest that the trapping mechanism of noble gases in CVD diamonds is ion implantation during diamond growth. The degrees of fractionation of heavy noble gases were also in good agreement with those in ureilites. The vapor-growth hypothesis is discussed in comparison with the impact-shock hypothesis as a better model for the origin of diamonds in ureilites. The diamond (and graphite, amorphous carbon, too) may have been deposited on early condensates such as Re, Ir, W, etc. This model explains the chemical features of vein material in ureilites; the refractory siderophile elements are enriched in carbon and noble gases and low in normal siderophiles. The vapor-growth model is also compatible with the oxygen isotopic data of ureilites which suggests that nebular processes are primarily responsible for the composition of ureilites.

  9. Analysis of stray radiation produced by the advanced light source (1.9 GeV synchrotron radiation source) at Lawrence Berkeley Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Ajemian, Robert C. [Univ. of North Carolina, Chapel Hill, NC (United States). Dept. of Environmental Sciences and Engineering

    1995-01-01

    The yearly environmental dose equivalent likely to result at the closest site boundary from the Advanced Light Source was determined by generating multiple linear regressions. The independent variables comprised quantified accelerator operating parameters and measurements from synchronized, in-close (outside shielding prior to significant atmospheric scattering), state-of-the-art neutron remmeters and photon G-M tubes. Neutron regression models were more successful than photon models due to lower relative background radiation and redundant detectors at the site boundary. As expected, Storage Ring Beam Fill and Beam Crashes produced radiation at a higher rate than gradual Beam Decay; however, only the latter did not include zero in its 95% confidence interval. By summing for all three accelerator operating modes, a combined yearly DE of 4.3 mRem/yr with a 90% CI of (0.04-8.63) was obtained. These results fall below the DOE reporting level of 10 mRem/yr and suggest repeating the study with improved experimental conditions.

  10. Analysis of stray radiation produced by the advanced light source (1.9 GeV synchrotron radiation source) at Lawrence Berkeley Laboratory

    International Nuclear Information System (INIS)

    Ajemian, R.C.

    1995-01-01

    The yearly environmental dose equivalent likely to result at the closest site boundary from the Advanced Light Source was determined by generating multiple linear regressions. The independent variables comprised quantified accelerator operating parameters and measurements from synchronized, in-close (outside shielding prior to significant atmospheric scattering), state-of-the-art neutron remmeters and photon G-M tubes. Neutron regression models were more successful than photon models due to lower relative background radiation and redundant detectors at the site boundary. As expected, Storage Ring Beam Fill and Beam Crashes produced radiation at a higher rate than gradual Beam Decay; however, only the latter did not include zero in its 95% confidence interval. By summing for all three accelerator operating modes, a combined yearly DE of 4.3 mRem/yr with a 90% CI of (0.04-8.63) was obtained. These results fall below the DOE reporting level of 10 mRem/yr and suggest repeating the study with improved experimental conditions

  11. Photo-electron spectroscopy using synchrotron radiation of molecular radicals and fragments produced by laser photo-dissociation

    International Nuclear Information System (INIS)

    Nahon, Laurent

    1991-01-01

    This research thesis reports the combined use of a laser and of a synchrotron radiation in order to respectively photo-dissociate a molecule and to photo-ionize fragments which are analysed by photo-electron spectroscopy. This association allows, on the one hand, radical photo-ionization to be studied, and, on the other hand, polyatomic molecule photo-dissociation to be studied. The author studied the photo-excitation and/or photo-ionization in layer 4d (resp. 3d) of atomic iodine (resp. bromine) produced almost complete laser photo-dissociation of I_2 (resp. Br_2). He discuses the processes of relaxation of transitions from valence 4d to 5p (resp. 3d to 4p) which occur either by direct self-ionization or by resonant Auger effect, and reports the study of photo-dissociation of s-tetrazine (C_2N_4H_2) [fr

  12. COLLISIONLESS SHOCKS IN A PARTIALLY IONIZED MEDIUM. II. BALMER EMISSION

    Energy Technology Data Exchange (ETDEWEB)

    Morlino, G.; Bandiera, R.; Blasi, P.; Amato, E. [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy)

    2012-12-01

    Strong shocks propagating into a partially ionized medium are often associated with optical Balmer lines. This emission is due to impact excitation of neutral hydrogen by hot protons and electrons in the shocked gas. The structure of such Balmer-dominated shocks has been computed in a previous paper, where the distribution function of neutral particles was derived from the appropriate Boltzmann equation including coupling with ions and electrons through charge exchange and ionization. This calculation showed how the presence of neutrals can significantly modify the shock structure through the formation of a neutral-induced precursor ahead of the shock. Here we follow up on our previous work and investigate the properties of the resulting Balmer emission, with the aim of using the observed radiation as a diagnostic tool for shock parameters. Our main focus is on supernova remnant shocks, and we find that, for typical parameters, the H{alpha} emission typically has a three-component spectral profile, where (1) a narrow component originates from upstream cold hydrogen atoms, (2) a broad component comes from hydrogen atoms that have undergone charge exchange with shocked protons downstream of the shock, and (3) an intermediate component is due to hydrogen atoms that have undergone charge exchange with warm protons in the neutral-induced precursor. The relative importance of these three components depends on the shock velocity, on the original degree of ionization, and on the electron-ion temperature equilibration level. The intermediate component, which is the main signature of the presence of a neutral-induced precursor, becomes negligible for shock velocities {approx}< 1500 km s{sup -1}. The width of the intermediate line reflects the temperature in the precursor, while the width of the narrow one is left unaltered by the precursor. In addition, we show that the profiles of both the intermediate and broad components generally depart from a thermal distribution, as a

  13. Electron transport and shock ignition

    Energy Technology Data Exchange (ETDEWEB)

    Bell, A R; Tzoufras, M, E-mail: t.bell1@physics.ox.ac.uk [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom)

    2011-04-15

    Inertial fusion energy (IFE) offers one possible route to commercial energy generation. In the proposed 'shock ignition' route to fusion, the target is compressed at a relatively low temperature and then ignited using high intensity laser irradiation which drives a strong converging shock into the centre of the fuel. With a series of idealized calculations we analyse the electron transport of energy into the target, which produces the pressure responsible for driving the shock. We show that transport in shock ignition lies near the boundary between ablative and heat front regimes. Moreover, simulations indicate that non-local effects are significant in the heat front regime and might lead to increased efficiency by driving the shock more effectively and reducing heat losses to the plasma corona.

  14. Multiply charged ions of the oxygen - produced at interaction of laser radiation with two-element solids

    International Nuclear Information System (INIS)

    Bedilov, M.R.; Bedilov, R.M.; Kamalova, J.O.; Davletov, I.Yu.; Matnazarov, A.R.

    2007-01-01

    Full text: The interest to study of the oxygen multiply charged ions spectra produced at interaction laser radiation with one and two-element solids, is associate with possibility of creating laser and inertial thermonuclear syntheses, effective sources of multiply charged ions and nuclei atoms elements, plasma lasers, lasers on multiply charged transition, design of radiation-resistant materials and others. The present time many works is devoted to multiply charged ions, obtained from one element targets. Experimental results of study charge and energy spectra multiply charged ions of the oxygen, formed at interaction laser radiation with one and two-element solids are given in this work. Our experiments, we used installation, which is described in [1]. Neodymium laser had following parameters: wavelength 1.06 μm; intensity q = (0.1 h 1000) GW/sm 2 ; angle of incidence = 180. Were study one element Al, and two-element Al 2 O 3 , Y 2 O 3 targets by a diameter of 10 mm and thickness of 3 mm. Analysis obtained charge and energy spectra of multiply charged ions one (Al) and two-element (Al 2 O 3 , Y 2 O 3 ) targets depending on intensity of laser radiation and targets components reveal the following: - maximal charge number one element target (Al) at q 500 GW/sm 2 is equal Z max = 6 and all peaks corresponding to charge numbers Z = 1 - 6 well resolved, but two-element targets (Al 2 O 3 ) Z max ions Al decrease before 3. Also it is necessary to note that, Z max ions of the oxygen depend on target components. In case Al 2 O 3 and Y 2 O 3 maximal charge number of oxygen ions are equal Z max = 6 and 3, accordingly; - obtained charge and energy spectra of oxygen ions being included in two-element targets, are indicative of that, general regularities of the change Z max , E max and structures charge and energy spectra depending on q laser are saved. However they hang by target components; - common features and some differences of energy spectra multiply charged oxygen ions

  15. Electron spin resonance of the solvation of radiation-produced silver atoms in alcohol-water mixtures

    International Nuclear Information System (INIS)

    Li, A.S.W.; Kevan, L.

    1982-01-01

    Frozen solutions of silver salts exposed to 60 Co γ-irradiation form silver atoms by reaction of radiation-produced electrons with the silver ion. At 4 K the silver atoms are initially produced in a nonequilibrium or presolvated state and upon brief thermal excitation to 77 K the first solvation shell geometry changes towards an equilibrium or solvated silver atom. This is most pronounced in water but also occurs in methanol, ethanol and n-propanol matrices. The changes in the electron spin resonance magnetic parameters upon silver atom solvation have been determined. In alcohol-water mixtures Ag 0 is preferentially solvated by polycrystalline water at low alcohol concentration. Above a particular alcohol mole percent Ag 0 suddenly changes its environment to a glassy alcohol one. This sudden change occurs at 17, 13 and 6 mol % methanol, ethanol and n-propanol, respectively. These mole percents correlate with the minimum of the excess enthalpy of mixing and with the hydrogen atom trapping ability of these alcohol-water mixtures. The results also suggest that the local environmental disorder around Ag 0 increases with alcohol chain length in alcohol-water frozen solutions. (author)

  16. The effect of shock dynamics on compressibility of ignition-scale National Ignition Facility implosions

    International Nuclear Information System (INIS)

    Zylstra, A. B.; Frenje, J. A.; Séguin, F. H.; Rosenberg, M. J.; Rinderknecht, H. G.; Gatu Johnson, M.; Li, C. K.; Manuel, M. J.-E.; Petrasso, R. D.; Sinenian, N.; Sio, H. W.; Hicks, D. G.; Dewald, E. L.; Robey, H. F.; Rygg, J. R.; Meezan, N. B.; Friedrich, S.; Bionta, R.; Atherton, J.; Barrios, M.

    2014-01-01

    The effects of shock dynamics on compressibility of indirect-drive ignition-scale surrogate implosions, CH shells filled with D 3 He gas, have been studied using charged-particle spectroscopy. Spectral measurements of D 3 He protons produced at the shock-bang time probe the shock dynamics and in-flight characteristics of an implosion. The proton shock yield is found to vary by over an order of magnitude. A simple model relates the observed yield to incipient hot-spot adiabat, suggesting that implosions with rapid radiation-power increase during the main drive pulse may have a 2× higher hot-spot adiabat, potentially reducing compressibility. A self-consistent 1-D implosion model was used to infer the areal density (ρR) and the shell center-of-mass radius (R cm ) from the downshift of the shock-produced D 3 He protons. The observed ρR at shock-bang time is substantially higher for implosions, where the laser drive is on until near the compression bang time (“short-coast”), while longer-coasting implosions have lower ρR. This corresponds to a much larger temporal difference between the shock- and compression-bang time in the long-coast implosions (∼800 ps) than in the short-coast (∼400 ps); this will be verified with a future direct bang-time diagnostic. This model-inferred differential bang time contradicts radiation-hydrodynamic simulations, which predict constant 700–800 ps differential independent of coasting time; this result is potentially explained by uncertainties in modeling late-time ablation drive on the capsule. In an ignition experiment, an earlier shock-bang time resulting in an earlier onset of shell deceleration, potentially reducing compression and, thus, fuel ρR

  17. The effect of shock dynamics on compressibility of ignition-scale National Ignition Facility implosions

    Energy Technology Data Exchange (ETDEWEB)

    Zylstra, A. B., E-mail: zylstra@mit.edu; Frenje, J. A.; Séguin, F. H.; Rosenberg, M. J.; Rinderknecht, H. G.; Gatu Johnson, M.; Li, C. K.; Manuel, M. J.-E.; Petrasso, R. D.; Sinenian, N.; Sio, H. W. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Hicks, D. G.; Dewald, E. L.; Robey, H. F.; Rygg, J. R.; Meezan, N. B.; Friedrich, S.; Bionta, R.; Atherton, J.; Barrios, M. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); and others

    2014-11-15

    The effects of shock dynamics on compressibility of indirect-drive ignition-scale surrogate implosions, CH shells filled with D{sup 3}He gas, have been studied using charged-particle spectroscopy. Spectral measurements of D{sup 3}He protons produced at the shock-bang time probe the shock dynamics and in-flight characteristics of an implosion. The proton shock yield is found to vary by over an order of magnitude. A simple model relates the observed yield to incipient hot-spot adiabat, suggesting that implosions with rapid radiation-power increase during the main drive pulse may have a 2× higher hot-spot adiabat, potentially reducing compressibility. A self-consistent 1-D implosion model was used to infer the areal density (ρR) and the shell center-of-mass radius (R{sub cm}) from the downshift of the shock-produced D{sup 3}He protons. The observed ρR at shock-bang time is substantially higher for implosions, where the laser drive is on until near the compression bang time (“short-coast”), while longer-coasting implosions have lower ρR. This corresponds to a much larger temporal difference between the shock- and compression-bang time in the long-coast implosions (∼800 ps) than in the short-coast (∼400 ps); this will be verified with a future direct bang-time diagnostic. This model-inferred differential bang time contradicts radiation-hydrodynamic simulations, which predict constant 700–800 ps differential independent of coasting time; this result is potentially explained by uncertainties in modeling late-time ablation drive on the capsule. In an ignition experiment, an earlier shock-bang time resulting in an earlier onset of shell deceleration, potentially reducing compression and, thus, fuel ρR.

  18. Coronal mass ejection shock fronts containing the two types of intermediate shocks

    International Nuclear Information System (INIS)

    Steinolfson, R.S.; Hundhausen, A.J.

    1990-01-01

    Numerical solutions of the time-dependent, magnetohydrodynamic (MHD) equations in two dimensions are used to demonstrate the formation of both types of intermediate shocks in a single shock front for physical conditions that are an idealization of those expected to occur in some observed coronal mass ejections. The key to producing such a shock configuration in the simulations is the use of an initial atmosphere containing a magnetic field representative of that in a coronal streamer with open field lines overlying a region of closed field lines. Previous attempts using just open field lines (perpendicular to the surface) produced shock configurations containing just one of the two intermediate shock types. A schematic of such a shock front containing both intermediate shock types has been constructed previously based solely on the known properties of MHD shocks from the Rankine-Hugoniot equations and specific requirements placed on the shock solution at points along the front where the shock normal and upstream magnetic field are aligned. The shock front also contains, at various locations along the front, a hydrodynamic (nonmagnetic) shock, a switch-on shock, and a fast shock in addition to the intermediate shocks. This particular configuration occurs when the shock front speed exceeds the upstream (preshock) intermediate wave speed but is less than a critical speed defined in the paper (equation 1) along at least some portion of the shock front. A distinctive feature of the front is that it is concave upward (away from the surface) near the region where the field in the preshock plasma is normal to the front of near the central portion of the shock front

  19. Converging cylindrical shocks in ideal magnetohydrodynamics

    International Nuclear Information System (INIS)

    Pullin, D. I.; Mostert, W.; Wheatley, V.; Samtaney, R.

    2014-01-01

    We consider a cylindrically symmetrical shock converging onto an axis within the framework of ideal, compressible-gas non-dissipative magnetohydrodynamics (MHD). In cylindrical polar co-ordinates we restrict attention to either constant axial magnetic field or to the azimuthal but singular magnetic field produced by a line current on the axis. Under the constraint of zero normal magnetic field and zero tangential fluid speed at the shock, a set of restricted shock-jump conditions are obtained as functions of the shock Mach number, defined as the ratio of the local shock speed to the unique magnetohydrodynamic wave speed ahead of the shock, and also of a parameter measuring the local strength of the magnetic field. For the line current case, two approaches are explored and the results compared in detail. The first is geometrical shock-dynamics where the restricted shock-jump conditions are applied directly to the equation on the characteristic entering the shock from behind. This gives an ordinary-differential equation for the shock Mach number as a function of radius which is integrated numerically to provide profiles of the shock implosion. Also, analytic, asymptotic results are obtained for the shock trajectory at small radius. The second approach is direct numerical solution of the radially symmetric MHD equations using a shock-capturing method. For the axial magnetic field case the shock implosion is of the Guderley power-law type with exponent that is not affected by the presence of a finite magnetic field. For the axial current case, however, the presence of a tangential magnetic field ahead of the shock with strength inversely proportional to radius introduces a length scale R=√(μ 0 /p 0 ) I/(2 π) where I is the current, μ 0 is the permeability, and p 0 is the pressure ahead of the shock. For shocks initiated at r ≫ R, shock convergence is first accompanied by shock strengthening as for the strictly gas-dynamic implosion. The diverging magnetic field

  20. Converging cylindrical shocks in ideal magnetohydrodynamics

    KAUST Repository

    Pullin, D. I.

    2014-09-01

    We consider a cylindrically symmetrical shock converging onto an axis within the framework of ideal, compressible-gas non-dissipative magnetohydrodynamics (MHD). In cylindrical polar co-ordinates we restrict attention to either constant axial magnetic field or to the azimuthal but singular magnetic field produced by a line current on the axis. Under the constraint of zero normal magnetic field and zero tangential fluid speed at the shock, a set of restricted shock-jump conditions are obtained as functions of the shock Mach number, defined as the ratio of the local shock speed to the unique magnetohydrodynamic wave speed ahead of the shock, and also of a parameter measuring the local strength of the magnetic field. For the line current case, two approaches are explored and the results compared in detail. The first is geometrical shock-dynamics where the restricted shock-jump conditions are applied directly to the equation on the characteristic entering the shock from behind. This gives an ordinary-differential equation for the shock Mach number as a function of radius which is integrated numerically to provide profiles of the shock implosion. Also, analytic, asymptotic results are obtained for the shock trajectory at small radius. The second approach is direct numerical solution of the radially symmetric MHD equations using a shock-capturing method. For the axial magnetic field case the shock implosion is of the Guderley power-law type with exponent that is not affected by the presence of a finite magnetic field. For the axial current case, however, the presence of a tangential magnetic field ahead of the shock with strength inversely proportional to radius introduces a length scale R = √μ0/p0 I/(2π) where I is the current, μ0 is the permeability, and p0 is the pressure ahead of the shock. For shocks initiated at r ≫ R, shock convergence is first accompanied by shock strengthening as for the strictly gas-dynamic implosion. The diverging magnetic field then

  1. Converging cylindrical shocks in ideal magnetohydrodynamics

    KAUST Repository

    Pullin, D. I.; Mostert, W.; Wheatley, V.; Samtaney, Ravi

    2014-01-01

    We consider a cylindrically symmetrical shock converging onto an axis within the framework of ideal, compressible-gas non-dissipative magnetohydrodynamics (MHD). In cylindrical polar co-ordinates we restrict attention to either constant axial magnetic field or to the azimuthal but singular magnetic field produced by a line current on the axis. Under the constraint of zero normal magnetic field and zero tangential fluid speed at the shock, a set of restricted shock-jump conditions are obtained as functions of the shock Mach number, defined as the ratio of the local shock speed to the unique magnetohydrodynamic wave speed ahead of the shock, and also of a parameter measuring the local strength of the magnetic field. For the line current case, two approaches are explored and the results compared in detail. The first is geometrical shock-dynamics where the restricted shock-jump conditions are applied directly to the equation on the characteristic entering the shock from behind. This gives an ordinary-differential equation for the shock Mach number as a function of radius which is integrated numerically to provide profiles of the shock implosion. Also, analytic, asymptotic results are obtained for the shock trajectory at small radius. The second approach is direct numerical solution of the radially symmetric MHD equations using a shock-capturing method. For the axial magnetic field case the shock implosion is of the Guderley power-law type with exponent that is not affected by the presence of a finite magnetic field. For the axial current case, however, the presence of a tangential magnetic field ahead of the shock with strength inversely proportional to radius introduces a length scale R = √μ0/p0 I/(2π) where I is the current, μ0 is the permeability, and p0 is the pressure ahead of the shock. For shocks initiated at r ≫ R, shock convergence is first accompanied by shock strengthening as for the strictly gas-dynamic implosion. The diverging magnetic field then

  2. Converging cylindrical shocks in ideal magnetohydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Pullin, D. I. [Graduate Aerospace Laboratories, California Institute of Technology, Pasadena, California 91125 (United States); Mostert, W.; Wheatley, V. [School of Mechanical and Mining Engineering, University of Queensland, Queensland 4072 (Australia); Samtaney, R. [Mechanical Engineering, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal (Saudi Arabia)

    2014-09-15

    We consider a cylindrically symmetrical shock converging onto an axis within the framework of ideal, compressible-gas non-dissipative magnetohydrodynamics (MHD). In cylindrical polar co-ordinates we restrict attention to either constant axial magnetic field or to the azimuthal but singular magnetic field produced by a line current on the axis. Under the constraint of zero normal magnetic field and zero tangential fluid speed at the shock, a set of restricted shock-jump conditions are obtained as functions of the shock Mach number, defined as the ratio of the local shock speed to the unique magnetohydrodynamic wave speed ahead of the shock, and also of a parameter measuring the local strength of the magnetic field. For the line current case, two approaches are explored and the results compared in detail. The first is geometrical shock-dynamics where the restricted shock-jump conditions are applied directly to the equation on the characteristic entering the shock from behind. This gives an ordinary-differential equation for the shock Mach number as a function of radius which is integrated numerically to provide profiles of the shock implosion. Also, analytic, asymptotic results are obtained for the shock trajectory at small radius. The second approach is direct numerical solution of the radially symmetric MHD equations using a shock-capturing method. For the axial magnetic field case the shock implosion is of the Guderley power-law type with exponent that is not affected by the presence of a finite magnetic field. For the axial current case, however, the presence of a tangential magnetic field ahead of the shock with strength inversely proportional to radius introduces a length scale R=√(μ{sub 0}/p{sub 0}) I/(2 π) where I is the current, μ{sub 0} is the permeability, and p{sub 0} is the pressure ahead of the shock. For shocks initiated at r ≫ R, shock convergence is first accompanied by shock strengthening as for the strictly gas-dynamic implosion. The

  3. Bow shock data analysis

    Science.gov (United States)

    Zipf, Edward C.; Erdman, Peeter W.

    1994-08-01

    The University of Pittsburgh Space Physics Group in collaboration with the Army Research Office (ARO) modeling team has completed a systematic organization of the shock and plume spectral data and the electron temperature and density measurements obtained during the BowShock I and II rocket flights which have been submitted to the AEDC Data Center, has verified the presence of CO Cameron band emission during the Antares engine burn and for an extended period of time in the post-burn plume, and have adapted 3-D radiation entrapment codes developed by the University of Pittsburgh to study aurora and other atmospheric phenomena that involve significant spatial effects to investigate the vacuum ultraviolet (VUV) and extreme ultraviolet (EUV) envelope surrounding the re-entry that create an extensive plasma cloud by photoionization.

  4. Behavioral and physiological changes produced by a supralethal dose of ionizing radiation: evidence for hormone-influenced sex differences in the rat

    International Nuclear Information System (INIS)

    Mickley, G.A.

    1980-01-01

    A sufficiently large and rapid dose of ionizing radiation produces an immediate but transient behavioral incapacitation. Acute hypotension often accompanies the disorder. Although the etiology of this syndrome is unclear, it has been suggested that an increase in histamine excretion contributes to it. Since histamine is known to interact with the endocrine system and since estrogens have been shown to prolong the life of animals exposed to potentially lethal doses of radiation, it was also hypothesized that females might be relatively less affected by an acute, large dose of ionizing radiation. Male and female rats were trained on an avoidance task, irradiated, and then retested. Females showed a less severe decrement after radiation exposure than males. Likewise, females did not suffer the severe hypotension normally associated with male radiogenic early transient incapacitation (ETI); rather, an acute hypertension was produced in females. A second series of experiments revealed that differences in male and female radiation response were eliminated by gonadectomy. Systemic estradiol injection produced strikingly feminine (i.e., superior) postirradiation avoidance responses as well as hypertension in neutered rats. Testosterone injections had no effect on either measure. Central nervous system alterations have been correlated with the ETI. Therefore, final experiments sought a possible central locus of the action of estradiol. It was found that exposure of the nucleus peopticus medialis to estrogens produces postirradiation benefits in avoidance performance and blood pressure similar to those seen after systemic estradiol treatments. Nucleus amygdaloideus medialis implants produced no such benefits

  5. On Modeling Risk Shocks

    OpenAIRE

    Dorofeenko, Victor; Lee, Gabriel; Salyer, Kevin; Strobel, Johannes

    2016-01-01

    Within the context of a financial accelerator model, we model time-varying uncertainty (i.e. risk shocks) through the use of a mixture Normal model with time variation in the weights applied to the underlying distributions characterizing entrepreneur productivity. Specifically, we model capital producers (i.e. the entrepreneurs) as either low-risk (relatively small second moment for productivity) and high-risk (relatively large second moment for productivity) and the fraction of both types is...

  6. Polarized bow shocks reveal features of the winds and environments of massive stars

    Science.gov (United States)

    Shrestha, Manisha

    2018-01-01

    Massive stars strongly affect their surroundings through their energetic stellar winds and deaths as supernovae. The bow shock structures created by fast-moving massive stars contain important information about the winds and ultimate fates of these stars as well as their local interstellar medium (ISM). Since bow shocks are aspherical, the light scattered in the dense shock material becomes polarized. Analyzing this polarization reveals details of the bow shock geometry as well as the composition, velocity, density, and albedo of the scattering material. With these quantities, we can constrain the properties of the stellar wind and thus the evolutionary state of the star, as well as the dust composition of the local ISM.In my dissertation research, I use a Monte Carlo radiative transfer code that I optimized to simulate the polarization signatures produced by both resolved and unresolved stellar wind bow shocks (SWBS) illuminated by a central star and by shock emission. I derive bow shock shapes and densities from published analytical calculations and smooth particle hydrodynamic (SPH) models. In the case of the analytical SWBS and electron scattering, I find that higher optical depths produce higher polarization and position angle rotations at specific viewing angles compared to theoretical predictions for low optical depths. This is due to the geometrical properties of the bow shock combined with multiple scattering effects. For dust scattering, the polarization signature is strongly affected by wavelength, dust grain properties, and viewing angle. The behavior of the polarization as a function of wavelength in these cases can distinguish among different dust models for the local ISM. In the case of SPH density structures, I investigate how the polarization changes as a function of the evolutionary phase of the SWBS. My dissertation compares these simulations with polarization data from Betelgeuse and other massive stars with bow shocks. I discuss the

  7. Teleconnected food supply shocks

    Science.gov (United States)

    Bren d'Amour, Christopher; Wenz, Leonie; Kalkuhl, Matthias; Steckel, Jan Christoph; Creutzig, Felix

    2016-03-01

    The 2008-2010 food crisis might have been a harbinger of fundamental climate-induced food crises with geopolitical implications. Heat-wave-induced yield losses in Russia and resulting export restrictions led to increases in market prices for wheat across the Middle East, likely contributing to the Arab Spring. With ongoing climate change, temperatures and temperature variability will rise, leading to higher uncertainty in yields for major nutritional crops. Here we investigate which countries are most vulnerable to teleconnected supply-shocks, i.e. where diets strongly rely on the import of wheat, maize, or rice, and where a large share of the population is living in poverty. We find that the Middle East is most sensitive to teleconnected supply shocks in wheat, Central America to supply shocks in maize, and Western Africa to supply shocks in rice. Weighing with poverty levels, Sub-Saharan Africa is most affected. Altogether, a simultaneous 10% reduction in exports of wheat, rice, and maize would reduce caloric intake of 55 million people living in poverty by about 5%. Export bans in major producing regions would put up to 200 million people below the poverty line at risk, 90% of which live in Sub-Saharan Africa. Our results suggest that a region-specific combination of national increases in agricultural productivity and diversification of trade partners and diets can effectively decrease future food security risks.

  8. Shock Waves

    CERN Document Server

    Jiang, Z

    2005-01-01

    The International Symposium on Shock Waves (ISSW) is a well established series of conferences held every two years in a different location. A unique feature of the ISSW is the emphasis on bridging the gap between physicists and engineers working in fields as different as gas dynamics, fluid mechanics and materials sciences. The main results presented at these meetings constitute valuable proceedings that offer anyone working in this field an authoritative and comprehensive source of reference.

  9. Effects of electromagnetic radiation produced by 3G mobile phones on rat brains: magnetic resonance spectroscopy, biochemical, and histopathological evaluation.

    Science.gov (United States)

    Dogan, M; Turtay, M G; Oguzturk, H; Samdanci, E; Turkoz, Y; Tasdemir, S; Alkan, A; Bakir, S

    2012-06-01

    The effects of electromagnetic radiation (EMR) produced by a third-generation (3G) mobile phone (MP) on rat brain tissues were investigated in terms of magnetic resonance spectroscopy (MRS), biochemistry, and histopathological evaluations. The rats were randomly assigned to two groups: Group 1 is composed of 3G-EMR-exposed rats (n = 9) and Group 2 is the control group (n = 9). The first group was subjected to EMR for 20 days. The control group was not exposed to EMR. Choline (Cho), creatinin (Cr), and N-acetylaspartate (NAA) levels were evaluated by MRS. Catalase (CAT) and glutathione peroxidase (GSH-Px) enzyme activities were measured by spectrophotometric method. Histopathological analyses were carried out to evaluate apoptosis in the brain tissues of both groups. In MRS, NAA/Cr, Cho/Cr, and NAA/Cho ratios were not significantly different between Groups 1 and 2. Neither the oxidative stress parameters, CAT and GSH-Px, nor the number of apoptotic cells were significantly different between Groups 1 and 2. Usage of short-term 3G MP does not seem to have a harmful effect on rat brain tissue.

  10. Contribution to the theoretical study of a high power microwave radiation produced by a relativistic electron beam

    International Nuclear Information System (INIS)

    Sellem, F.

    1997-01-01

    This thesis is dedicated to the study of microwave radiation produced by relativistic electron beams. The vircator (virtual cathode oscillator) is a powerful microwave source based on this principle. This device is described but the complexity of the physical processes involved makes computer simulation necessary before proposing a simplified model. The existent M2V code has been useful to simulate the behaviour of a vircator but the representation of some phenomena such as hot points, the interaction of waves with particles lacks reliability. A new code CODEX has been written, it can solve Maxwell equations on a double mesh system by a finite difference method. The electric and magnetic fields are directly computed from the scalar and vectorial potentials. This new code has been satisfactorily tested on 3 configurations: the bursting of an electron beam in vacuum, the evolution of electromagnetic fields in diode and the propagation of waves in a wave tube. CODEX has been able to simulate the behaviour of a vircator, the frequency and power are well predicted and some contributions to the problem of origin of microwave production have been made. It seems that the virtual cathode is not directly involved in the microwave production. (A.C.)

  11. Electron transfer from H2 and Ar to stored multiply charged argon ions produced by synchrotron radiation

    International Nuclear Information System (INIS)

    Kravis, S.D.; Church, D.A.; Johnson, B.M.; Meron, M.; Jones, K.W.; Levin, J.C.; Sellin, I.A.; Azuma, Y.; Berrah-Mansour, N.; Berry, H.G.; Druetta, M.

    1992-01-01

    The rate coefficients for electron transfer from Ar and H 2 to Ar q+ ions (3≤q≤6) have been measured using an ion-storage technique in a Penning ion trap. The ions were produced in the trap by K-shell photoionization of Ar atoms, using broadband synchrotron x-ray radiation. K-electron removal resulted in vacancy cascading, yielding a distribution of argon-ion charge states peaked near Ar 4+ . The stored ion gas had an initial temperature near 480 K. The basic data determining the rate coefficients k(Ar q+ ) are the storage time constants of each charge state in the trap, in the presence of a measured pressure of target gas. The results of the measurements (in units of 10 -9 cm 3 s -1 ) are k(Ar 3+ ,H 2 )=4.3(0.7), k(Ar 3+ ,Ar)=1.6(0.2), k(Ar 4+ ,H 2 )=5.2(0.6), k(Ar 4+ ,Ar)=2.5(0.3), k(Ar 5+ ,H 2 )=5.9(0.7), k(Ar 5+ ,Ar)=2.9(0.3), k(Ar 6+ ,H 2 )=8.5(1.2), and k(Ar 6+ ,Ar)=2.5(0.3)

  12. Airborne and truck-borne ``radiation footprints`` of areas producing, storing, using or being exposed to nuclear materials

    Energy Technology Data Exchange (ETDEWEB)

    Pavlik, B; Bottos, F [Picodas Group Inc., Richmond Hill, ON (Canada); Cuneen, P J [World Geoscience Corp. Ltd., Perth (Australia); Jurza, P; Hoeschl, V [Picodas Prague s.r.o., Prague (Czech Republic)

    1997-11-01

    The paper discusses the use of advanced Airborne Gamma Ray Spectrometer for environmental assessment of nuclear radiation in areas exposed to radioactive materials. The use of high capacity real time processors operating in parallel mode packaged into one mechanical enclosure together with navigation, allows implementation of highly sophisticated proprietary algorithms to produce results in absolute physical units. Airborne footprinting provides rapid, well defined spatial images of natural and manmade radioactive contamination. Integrated GPS guidance systems provides instant position information related to the internal geographical data base. Short time span of data acquisition provides consistent data. Airborne acquisition of data guarantees good spatial resolution. Airborne measurements are calculated via special algorithms in absolute units and related to the individual radioactive nuclei on the ground in real time. Full raw and calculated data recording is provided including the position coordinates. More precise results may be achieved via post flight processing. Principles of ground contamination estimates measured from the air and the sensitivities for different radioactive nuclei are also discussed. Results from an Ontario Hydro (Canada) test over a nuclear power plant, an Atom bomb blast measurements in Maralinga (Australia), after 40 years, and a Nuclear power plant in Slovakia and Uranium mining area in Germany are presented and discussed. (author). 6 refs, 1 fig.

  13. Airborne and truck-borne ''radiation footprints'' of areas producing, storing, using or being exposed to nuclear materials

    International Nuclear Information System (INIS)

    Pavlik, B.; Bottos, F.; Cuneen, P.J.; Jurza, P.; Hoeschl, V.

    1997-01-01

    The paper discusses the use of advanced Airborne Gamma Ray Spectrometer for environmental assessment of nuclear radiation in areas exposed to radioactive materials. The use of high capacity real time processors operating in parallel mode packaged into one mechanical enclosure together with navigation, allows implementation of highly sophisticated proprietary algorithms to produce results in absolute physical units. Airborne footprinting provides rapid, well defined spatial images of natural and manmade radioactive contamination. Integrated GPS guidance systems provides instant position information related to the internal geographical data base. Short time span of data acquisition provides consistent data. Airborne acquisition of data guarantees good spatial resolution. Airborne measurements are calculated via special algorithms in absolute units and related to the individual radioactive nuclei on the ground in real time. Full raw and calculated data recording is provided including the position coordinates. More precise results may be achieved via post flight processing. Principles of ground contamination estimates measured from the air and the sensitivities for different radioactive nuclei are also discussed. Results from an Ontario Hydro (Canada) test over a nuclear power plant, an Atom bomb blast measurements in Maralinga (Australia), after 40 years, and a Nuclear power plant in Slovakia and Uranium mining area in Germany are presented and discussed. (author)

  14. Properties of murine leukemia viruses produced by leukemic cells established from NIH Swiss mice with radiation-induced leukemia

    Energy Technology Data Exchange (ETDEWEB)

    Okumoto, Masaaki; Nishikawa, Ryosuke; Takamori, Yasuhiko; Iwai, Yoshiaki; Iwai, Mineko [Radiation Center of Osaka Prefecture, Sakai (Japan); Imai, Shunsuke; Morimoto, Junji; Tsubura, Yoshihiko

    1984-06-01

    Three leukemic cell lines, designated NIH-RL1, NIH-RL2 and NFS-RL1, were established from spleen and thymuses of NIH Swiss and NFS mice with radiation-induced leukemia. The culture fluids of these cell lines contained RNA-dependent DNA polymerase (RDDP) activities associated with particles of buoyant density of 1.15-1.17 (g/cm/sup 3/). The divalent cation reqirement of these enzymes was characteristic for that of murine leukemia viruses. In competition radioimmunoassay, a major core protein, p30, was detected in culture fluid of each leukemic cell line. Competition curves of viral p30 produced by these cell lines revealed that these viruses were very similar to those of xenotropic viruses of NZB mice. These viruses were undetectable both by XC plaque assay using SC-1 cells as an indicator cell, and by mink S/sup +/L/sup -/ focus induction assay. These viruses also lacked productive infectivity to mink lung cells (CCL-64), and were nononcogenic in syngeneic mice when the viruses were intrathymically inoculated.

  15. A Shocking Solar Nebula?

    OpenAIRE

    Liffman, Kurt

    2009-01-01

    It has been suggested that shock waves in the solar nebula formed the high temperature materials observed in meteorites and comets. It is shown that the temperatures at the inner rim of the solar nebula could have been high enough over a sufficient length of time to produce chondrules, CAIs, refractory dust grains and other high-temperature materials observed in comets and meteorites. The solar bipolar jet flow may have produced an enrichment of 16O in the solar nebula over time and the chond...

  16. Features of produced flows of multiply charged ions at interaction of laser radiation with single-component solids

    International Nuclear Information System (INIS)

    Bedilov, M.R.; Bedilov, R.M.; Beysembaeva, H.B.; Sabitov, M.S.; Kamalova, J.O.

    2006-01-01

    Full text: The results of study features of formation multiply charged ions spectra of single-component solids depending on a target element composition in an interval of laser radiation power density q = 10 7 / 10 12 W/cm 2 with using of the laser multiply charged mass spectrometer [1] are given in this work. As single-component targets are used Be, B, C, Al, Ti, Fe, Co, Ni, Cu, Ag, Ta, W, Pt, Au as tablets in diameter of 10 mm and thickness of 3-5 mm. Analysis of the obtained mass-charge and energy spectra of multiply charged ions depending on a target element composition has allowed us to find features of formation spectra and escape multiply charged ions of a single-component targets. These features consist in characteristic changes: a threshold produced of ions; formation of mass-charge and energy spectra of multiply charged ions; nonlinear dependence of maximal charge number (Z max ) of ions from power density (q) of the laser; etc. Experimentally it was found that, with target atomic weight increase, threshold power of ions occurrence, nonlinearity ionization target structure, and intensity of ions, and energy spectra of ions increase. Let's note that, in case of targets Be, B, C, Al by laser radiation it is completely ionized and multiply charged ions and nuclei Be 4+ , B 5+ , C 6+ , Al 13+ are formed. The major level of ionization is attained in case of targets from Ti (Ti 17+ ) and Co (Co 18+ ). It is peculiar that structure formation and escape of multiply charged ion flows with Z max and nuclei depending on target element composition corresponds to various maximal values q of the laser. Increase of the maximal charge number of ions (atoms) observed with increase q of the laser for all investigated targets has nonlinear dependence in various levels that is especially shown beginning from q≥ 10 11 W/cm 2 . It is found that depending on target element composition multiply charged ions have a wide energy range with a maximum of allocation. With increase

  17. POSTURAL SHOCK IN PREGNANCY

    Science.gov (United States)

    Wilkening, Ralph L.; Knauer, John; Larson, Roger K.

    1955-01-01

    Signs and symptoms of shock may be produced in some patients in late pregnancy by putting them in the dorsal recumbent posture. Change from this position will relieve the condition. The features of the supine hypotensive syndrome can be duplicated by applying pressure to the abdomen with the patient in a lateral position. The postural variations of venous pressure, blood pressure, and pulse appear to be due to obstruction of venous return from the lower portion of the body caused by the large uterus of late pregnancy compressing the vena cava. When shock is observed in a woman in late pregnancy, she should be turned to a lateral position before more active measures of treatment are begun. ImagesFigure 1. PMID:14351983

  18. Undercuts by Laser Shock Forming

    International Nuclear Information System (INIS)

    Wielage, Hanna; Vollertsen, Frank

    2011-01-01

    In laser shock forming TEA-CO 2 -laser induced shock waves are used to form metal foils, such as aluminum or copper. The process utilizes an initiated plasma shock wave on the target surface, which leads to a forming of the foil. A challenge in forming technologies is the manufacturing of undercuts. By conventional forming methods these special forms are not feasible. In this article, it is presented that undercuts in the micro range can be produced by laser shock deep drawing. Different drawing die diameters, drawing die depths and the material aluminum in the thicknesses 20 and 50 μm were investigated. It will be presented that smaller die diameters facilitate undercuts compared to bigger die diameters. The phenomena can be explained by Barlow's formula. Furthermore, it is shown which maximum undercut depth at different die diameters can be reached. To this end, cross-sections of the different parameter combinations are displayed.

  19. Line emission processes in atomic and molecular shocks

    International Nuclear Information System (INIS)

    Shull, J.M.

    1988-01-01

    The review discusses the observations and theoretical models of interstellar shock waves in diffuse and molecular clouds. After summarizing the relevant gas dynamics, atomic, molecular and grain processes, and physics of radiative and magnetic precursors, the author describes observational diagnostics of shocks. This paper concludes with a discussion of two topics: unstable or non-steady shocks and thermal conduction in metal-rich shocks

  20. Simulation of turbulent flows containing strong shocks

    International Nuclear Information System (INIS)

    Fryxell, Bruce; Menon, Suresh

    2008-01-01

    Simulation of turbulent flows with strong shocks is a computationally challenging problem. The requirements for a method to produce accurate results for turbulence are orthogonal to those needed to treat shocks properly. In order to prevent an unphysical rate of decay of turbulent structures, it is necessary to use a method with very low numerical dissipation. Because of this, central difference schemes are widely used. However, computing strong shocks with a central difference scheme can produce unphysical post-shock oscillations that corrupt the entire flow unless additional dissipation is added. This dissipation can be difficult to localize to the area near the shock and can lead to inaccurate treatment of the turbulence. Modern high-resolution shock-capturing methods usually use upwind algorithms to provide the dissipation necessary to stabilize shocks. However, this upwind dissipation can also lead to an unphysical rate of decay of the turbulence. This paper discusses a hybrid method for simulating turbulent flows with strong shocks that couples a high-order central difference scheme with a high-resolution shock-capturing method. The shock-capturing method is used only in the vicinity of discontinuities in the flow, whereas the central difference scheme is used in the remainder of the computational domain. Results of this new method will be shown for a variety of test problems. Preliminary results for a realistic application involving detonation in gas-particle flows will also be presented.

  1. Nonequilibrium chemistry in shocked molecular clouds

    International Nuclear Information System (INIS)

    Iglesias, E.R.; Silk, J.

    1978-01-01

    The gas phase chemistry is studied behind a 10 km s -1 shock propagating into a dense molecular cloud. Our principal conclusions are that the concentrations of certain molecules (CO, NH 3 , HCN, N 2 ) are unperturbed by the shock; other molecules (H 2 CO, CN, HCO + ) are greatly decreased in abundance; and substantial amounts of H 2 O, HCO, and CH 4 are produced. Approximately 10 6 yr (independent of the density) must elapse after shock passage before chemical equilibrium is attained

  2. Studies of radiation-produced radicals and radical ions. Progress report, June 1, 1981-August 31, 1982

    International Nuclear Information System (INIS)

    Williams, T.F.

    1982-01-01

    The discovery and characterization of novel radical ions produced by the γ irradiation of solids continues to be a fertile field for investigation. This Progress Report describes the generation and ESR identification of several new paramagnetic species, some of which have long been sought as important intermediates in radiation chemistry. We have also contributed to a general theoretical problem in ESR spectroscopy. Solid-state studies of electron attachment reactions, both non-dissociative and dissociative, reveal interesting structural and chemical information about the molecular nature of these processes for simple compounds. In particular, ESR measurements of the spin distribution in the products allow a fairly sharp distinction to be drawn between radical anions and radical-anion pairs or adducts. Dimer radical anion formation can also take place but the crystal structure plays a role in this process, as expected. Some radical anions undergo photolysis to give radical-anion pairs which may then revert back to the original radical anion by a thermal reaction. The chemistry of these reversible processes is made more intricate by a competing reaction in which the radical abstracts a hydrogen atom from a neighboring molecule. However, the unraveling of this complication has also served to extend our knowledge of the role of quantum tunneling in chemical reactions. The results of this investigation testify to the potential of solid-state techniques for the study of novel and frangible radical ions. Progress in this field shows no sign of abating, as witness the recent discovery of perfluorocycloalkane radical anions and alkane radical cations

  3. Recognition, signaling, and repair of DNA double-strand breaks produced by ionizing radiation in mammalian cells: the molecular choreography.

    Science.gov (United States)

    Thompson, Larry H

    2012-01-01

    The faithful maintenance of chromosome continuity in human cells during DNA replication and repair is critical for preventing the conversion of normal diploid cells to an oncogenic state. The evolution of higher eukaryotic cells endowed them with a large genetic investment in the molecular machinery that ensures chromosome stability. In mammalian and other vertebrate cells, the elimination of double-strand breaks with minimal nucleotide sequence change involves the spatiotemporal orchestration of a seemingly endless number of proteins ranging in their action from the nucleotide level to nucleosome organization and chromosome architecture. DNA DSBs trigger a myriad of post-translational modifications that alter catalytic activities and the specificity of protein interactions: phosphorylation, acetylation, methylation, ubiquitylation, and SUMOylation, followed by the reversal of these changes as repair is completed. "Superfluous" protein recruitment to damage sites, functional redundancy, and alternative pathways ensure that DSB repair is extremely efficient, both quantitatively and qualitatively. This review strives to integrate the information about the molecular mechanisms of DSB repair that has emerged over the last two decades with a focus on DSBs produced by the prototype agent ionizing radiation (IR). The exponential growth of molecular studies, heavily driven by RNA knockdown technology, now reveals an outline of how many key protein players in genome stability and cancer biology perform their interwoven tasks, e.g. ATM, ATR, DNA-PK, Chk1, Chk2, PARP1/2/3, 53BP1, BRCA1, BRCA2, BLM, RAD51, and the MRE11-RAD50-NBS1 complex. Thus, the nature of the intricate coordination of repair processes with cell cycle progression is becoming apparent. This review also links molecular abnormalities to cellular pathology as much a possible and provides a framework of temporal relationships. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Image-producing procedures for non-medical applications. Benefits, risks, radiation protection; Bildgebende Verfahren im nicht medizinischen Bereich. Nutzen, Risiken, Strahlenschutz

    Energy Technology Data Exchange (ETDEWEB)

    Czarwinski, Renate [Bundesamt fuer Strahlenschutz, Berlin (Germany); Estier, Sybille [Bundesamt fuer Gesundheit (BAG), Liebefeld (Switzerland). Direktionsbereich Verbraucherschutz; Huhn, Walter [Ministerium fuer Arbeit, Integration und Soziales NRW, Duesseldorf (Germany); Lorenz, Bernd [Lorenz Consulting, Essen (Germany); Vahlbruch, Jan [Hannover Univ. (Germany). Inst. fuer Radiooekologie und Strahlenschutz (IRS); Henning, Ulrich; Michel, Rolf

    2016-05-01

    A survey is given of image-producing procedures for non-medical applications, and this under technical, juridical and radiation protection aspects. The historical development of these procedures is also described. An example is given for today's practical application.

  5. Comparison of the cytological effects produced by ionizing radiations of different LET. Progress report, March 1974--April 1975

    International Nuclear Information System (INIS)

    Riley, E.F. Jr.

    1975-01-01

    Progress is reported on the following research projects: RBE of neutrons and x radiation for effects on rat lens epithelium; effects of x radiation on tumor cell transplants in mice; effects of fast neutrons on ascites tumors; the sparing effect of dose fractionation in the wounded rat lens; and DNA synthesis in wounded rat lens at various times after irradiation. (U.S.)

  6. Electron Dropout Echoes Induced by Interplanetary Shock: A Statistical Study

    Science.gov (United States)

    Liu, Z.; Zong, Q.; Hao, Y.; Zhou, X.; Ma, X.; Liu, Y.

    2017-12-01

    "Electron dropout echo" as indicated by repeated moderate dropout and recovery signatures of the flux of energetic electron in the out radiation belt region has been investigated systematically. The electron dropout and its echoes are usually found for higher energy (> 300 keV) channels fluxes, whereas the flux enhancements are obvious for lower energy electrons simultaneously after the interplanetary shock arrives at the Earth's geosynchronous orbit. 104 dropout echo events have been found from 215 interplanetary shock events from 1998 to 2007 based on LANL satellite data. In analogy to substorm injections, these 104 events could be naturally divided into two categories: dispersionless (49 events) or dispersive (55 events) according to the energy dispersion of the initial dropout. It is found that locations of dispersionless events are distributed mainly in the duskside magnetosphere. Further, the obtained locations derived from dispersive events with the time-of-flight technique of the initial dropout regions are mainly located at the duskside as well. Statistical studies have shown that the effect of shock normal, interplanetary magnetic field Bz and solar wind dynamic pressure may be insignificant to these electron dropout events. We suggest that the electric field impulse induced by the IP shock produces a more pronounced inward migration of electrons at the dusk side, resulting in the observed dusk-side moderate dropout of electron flux and its consequent echoes.

  7. Shock parameter calculations at weak interplanetary shock waves

    Directory of Open Access Journals (Sweden)

    J. M. Gloag

    2005-02-01

    Full Text Available A large set of interplanetary shock waves observed using the Ulysses spacecraft is analysed in order to determine their local parameters. For the first time a detailed analysis is extended to the thermodynamic properties of a large number of events. The intention is to relate the shock parameters to the requirements set by MHD shock theory. A uniform approach is adopted in the selection of up and downstream regions for this analysis and applied to all the shock waves. Initially, the general case of a 3 component adiabatic plasma is considered. However, the calculation of magnetosonic and Alfvénic Mach numbers and the ratio of downstream to upstream entropy produce some unexpected results. In some cases there is no clear increase in entropy across the shock and also the magnetosonic Mach number can be less than 1. It is found that a more discerning use of data along with an empirical value for the polytropic index can raise the distribution of downstream to upstream entropy ratios to a more acceptable level. However, it is also realised that many of these shocks are at the very weakest end of the spectrum and associated phenomena may also contribute to the explanation of these results.

  8. Study of the X radiation between 10 and 100 keV produced in and above the atmosphere

    International Nuclear Information System (INIS)

    Rothenflug, Robert

    1969-01-01

    To measure the X radiation within this energy range we used a detector consisting of a NaI(Tl) scintillator combined with a photomultiplier, of surface area 7 cm 2 and yield close to 1 between 10 and 100 keV. The detection system was carried by stratospheric balloons to altitudes (of the order of 40 km) where the atmosphere was sufficiently transparent to allow observation of radiation from outside the atmosphere. At the same time the atmosphere is the centre of ionising radiations which give rise to parasitic X-rays in air and in the materials surrounding the detector. The first part of this report is devoted to a study of these parasitic radiations for the purpose of calculating the different components. The second part deals with diffuse X radiation of extra-terrestrial origin. Measurements of the radiation in 3 different directions showed that it is isotropic within the limits of experimental accuracy, of the order of 20 per cent. The diffuse X-ray spectrum takes the form dN/dE = (2.1 ± 0.4).10 2 E -2.43±0.05 ph/cm 2 .s.ster.keV for E expressed in keV, between 14 and 90 keV., The last part is devoted to a discussion on the possible origins of the diffuse radiation. (author) [fr

  9. Measurements for the radiation spectra of fast Z-pinches produced at compression of multi-wire arrays on the 'Angara-5-1' facility

    International Nuclear Information System (INIS)

    Bolkhovitinov, E.A.; Rupasov, A.A.; Shikanov, A.S.; Fedulov, M.V.; Grabovsky, E.V.; Gritsuk, A.N.; Oleinik, G.M.; Volkov, G.S.

    2010-01-01

    Complete text of publication follows. The measurements results on the radiation spectra of fast z-pinches produced at compression of cylindrical multi-wire tungsten and aluminum arrays in the experiments on a high-current 'Angara-5-1' facility are presented. Cylindrical multi-wire arrays has linear mass 200-400 μg/cm and the initial diameter 12-20 mm. The pinch current was about 3 MA with pulse duration of 140 ns and peak power 3 TW. The radiation spectra are measured within the range of 50-900 eV quanta by a spectrometer with transmission diffraction grating, where the radiation is recorded on the UF-4 X-ray film. An electromagnetic curtain shutter was used to protect the transmission grating from fast microparticles produced by the erosion of high-voltage electrodes. The radiation spectrum of 1-3 keV quanta was recorded by a convex crystal wide-range spectrometer. Total yield of the radiation was measured by a thermocouple calorimeter. The main part of the tungsten plasma radiative energy proves to correspond to the quasi-continuous spectrum within the range of 80-300 eV quanta. Measurements of the tungsten plasma radiation spectrum with spatial resolution by a pinch radius have shown that the effective transversal size (diameter) of the pinch as not higher than 1 mm. In the case of aluminum plasma an intensive linear radiation of the [H]- and [He]-like ions have been recorded along with a continuous and linear radiation of the [Li]- and [Be]-like ions with the range of 100-300 eV quanta. Spectral measurements of the aluminum plasma radiation with spatial resolution by the pinch radius have shown that the effective transversal size (diameter) of the pinch is around the value of 1.5 mm. Within the framework of the stationary collisional-radiative model, in respect of the [H]- and [He]-like ion spectral lines relative intensities, the parameters of the aluminum plasma pinch, namely, the electron temperature T e ∼ 550 eV and electron density n e ∼ 3 x 10 20 cm

  10. Applications of Radiative Heating for Space Exploration

    Science.gov (United States)

    Brandis, Aaron

    2017-01-01

    Vehicles entering planetary atmospheres at high speeds (6 - 12 kms) experience intense heating by flows with temperatures of the order 10 000K. The flow around the vehicle experiences significant dissociation and ionization and is characterized by thermal and chemical non-equilibrium near the shock front, relaxing toward equilibrium. Emission from the plasma is intense enough to impart a significant heat flux on the entering spacecraft, making it necessary to predict the magnitude of radiative heating. Shock tubes represent a unique method capable of characterizing these processes in a flight-similar environment. The Electric Arc Shock tube (EAST) facility is one of the only facilities in its class, able to produce hypersonic flows at speeds up to Mach 50. This talk will review the characterization of radiation measured in EAST with simulations by the codes DPLR and NEQAIR, and in particular, focus on the impact these analyses have on recent missions to explore the solar system.

  11. Hugoniot measurements of double-shocked precompressed dense xenon plasmas

    Science.gov (United States)

    Zheng, J.; Chen, Q. F.; Gu, Y. J.; Chen, Z. Y.

    2012-12-01

    The current partially ionized plasmas models for xenon show substantial differences since the description of pressure and thermal ionization region becomes a formidable task, prompting the need for an improved understanding of dense xenon plasmas behavior at above 100 GPa. We performed double-shock compression experiments on dense xenon to determine accurately the Hugoniot up to 172 GPa using a time-resolved optical radiation method. The planar strong shock wave was produced using a flyer plate impactor accelerated up to ˜6 km/s with a two-stage light-gas gun. The time-resolved optical radiation histories were acquired by using a multiwavelength channel optical transience radiance pyrometer. Shock velocity was measured and mass velocity was determined by the impedance-matching methods. The experimental equation of state of dense xenon plasmas are compared with the self-consistent fluid variational calculations of dense xenon in the region of partial ionization over a wide range of pressures and temperatures.

  12. Development of a two-dimensional imaging system for clinical applications of intravenous coronary angiography using intense synchrotron radiation produced by a multipole wiggler

    International Nuclear Information System (INIS)

    Hyodo, K.; Ando, M.; Oku, Y.; Yamamoto, S.; Takeda, T.; Itai, Y.; Ohtsuka, S.; Sugishita, Y.; Tada, J.

    1998-01-01

    A two-dimensional clinical intravenous coronary angiography system, comprising a large-size View area produced by asymmetrical reflection from a silicon crystal using intense synchrotron radiation from a multipole wiggler and a two-dimensional detector with an image intensifier, has been completed. An advantage of the imaging system is that two-dimensional dynamic imaging of the cardiovascular system can be achieved due to its two-dimensional radiation field. This world-first two-dimensional system has been successfully adapted to clinical applications. Details of the imaging system are described in this paper

  13. Development of a two-dimensional imaging system for clinical applications of intravenous coronary angiography using intense synchrotron radiation produced by a multipole wiggler

    Energy Technology Data Exchange (ETDEWEB)

    Hyodo, K.; Ando, M. [High Energy Accelerator Research Organization, Inst. of Material Structure Sciences, Tsukuba (Japan); Oku, Y.; Yamamoto, S. [Graduated School for Advanced Sciences, Tsukuba (Japan); Takeda, T.; Itai, Y.; Ohtsuka, S.; Sugishita, Y. [The Univ. of Tsukuba, Inst. of Clinical Medicine, Tsukuba (Japan); Tada, J. [The Univ. of Tsukuba, Inst. of Basic Medical Sciences, Tsukuba (Japan)

    1998-05-01

    A two-dimensional clinical intravenous coronary angiography system, comprising a large-size View area produced by asymmetrical reflection from a silicon crystal using intense synchrotron radiation from a multipole wiggler and a two-dimensional detector with an image intensifier, has been completed. An advantage of the imaging system is that two-dimensional dynamic imaging of the cardiovascular system can be achieved due to its two-dimensional radiation field. This world-first two-dimensional system has been successfully adapted to clinical applications. Details of the imaging system are described in this paper. 18 refs.

  14. Studies of new light resonances decaying into two hadronic jets produced in association with a radiated jet

    CERN Document Server

    Li, Zhiying

    This report presents combinatorics studies in the search for a resonance of below 800 GeV which decay product is a pair of hadronic jets from quarks. The resonance, predicted as a dark matter mediator, has couplings to dark matter particles as well as quarks and gluons. The resonance is created in association with a radiated object that can be either a photon or a jet. In the case of the radiation being a jet, the dijet from the resonance and the radiated jet cannot be distinguished. Choosing the wrong dijet to reconstruct the resonance decreases the sensitivity of the search. The study focuses on studies that help improve the search sensitivity. The signal samples used in this thesis are generated with Monte Carlo simulation and passed through the ATLAS detector simulation. Firstly, in an attempt to identify the jet from radiation, samples where a jet is radiated and a photon is radiated are compared. However, due to the differences in the sample generations, this attempt does not lead to a successful identi...

  15. Electron velocity distributions near collisionless shocks

    International Nuclear Information System (INIS)

    Feldman, W.C.

    1984-01-01

    Recent studies of the amount of electron heating and of the shapes of electron velocity distributions across shocks near the earth are reviewed. It is found that electron heating increases with increasing shock strength but is always less than the ion heating. The scale length of electron heating is also less than that for the ions. Electron velocity distributions show characteristic shapes which depend on the strength of the shocks. At the weaker shocks, electron heating is mostly perpendicular to the ambient magnetic field, bar B, and results in Gaussian-shaped velocity distributions at low-to-moderate energies. At the stronger shocks, parallel heating predominates resulting in flat-topped velocity distributions. A reasonable interpretation of these results indicates that at the weaker shocks electron heating is dominated by a tendency toward conservation of the magnetic moment. At the stronger fast-mode shocks, this heating is thought to be dominated by an acceleration parallel to bar B produced by the macroscopic shock electric field followed by beam driven plasma instabilities. Some contribution to the heating at the stronger shocks from conservation of the magnetic moment and cross-field current-driven instabilities cannot be ruled out. Although the heating at slow-mode shocks is also dominated by instabilities driven by magnetic field-aligned electron beams, their acceleration mechanism is not yet established

  16. Entropy Generation Across Earth's Bow Shock

    Science.gov (United States)

    Parks, George K.; McCarthy, Michael; Fu, Suiyan; Lee E. s; Cao, Jinbin; Goldstein, Melvyn L.; Canu, Patrick; Dandouras, Iannis S.; Reme, Henri; Fazakerley, Andrew; hide

    2011-01-01

    Earth's bow shock is a transition layer that causes an irreversible change in the state of plasma that is stationary in time. Theories predict entropy increases across the bow shock but entropy has never been directly measured. Cluster and Double Star plasma experiments measure 3D plasma distributions upstream and downstream of the bow shock that allow calculation of Boltzmann's entropy function H and his famous H-theorem, dH/dt O. We present the first direct measurements of entropy density changes across Earth's bow shock. We will show that this entropy generation may be part of the processes that produce the non-thermal plasma distributions is consistent with a kinetic entropy flux model derived from the collisionless Boltzmann equation, giving strong support that solar wind's total entropy across the bow shock remains unchanged. As far as we know, our results are not explained by any existing shock models and should be of interests to theorists.

  17. Radiation-hydrodynamics of HII regions and molecular clouds

    International Nuclear Information System (INIS)

    Sandford, M.T. II; Whitaker, R.W.; Klein, R.I.

    1981-01-01

    Two-dimensional calculations of ionization-shock fronts surrounding neutral cloud clumps reveal that a radiation-driven implosion of the clump can occur. The implosion of a cloud clump results in the formation of density enhancements that may eventually form low mass stars. The smaller globules produced may become Herbig-Haro objects, or maser sources

  18. Transient shocks beyond the heliopause

    International Nuclear Information System (INIS)

    Fermo, R L; Pogorelov, N V; Burlaga, L F

    2015-01-01

    The heliopause is a rich, dynamic surface affected by the time-dependent solar wind. Stream interactions due to coronal mass ejections (CMEs), corotating interaction regions (CIRs), and other transient phenomena are known to merge producing global merged interaction regions (GMIRs). Numerical simulations of the solar wind interaction with the local interstellar medium (LISM) show that GMIRs, as well other time-dependent structures in the solar wind, may produce compression/rarefaction waves and shocks in the LISM behind the heliopause. These shocks may initiate wave activity observed by the Voyager spacecraft. The magnetometer onboard Voyager 1 indeed observed a few structures that may be interpreted as shocks. We present numerical simulations of such shocks in the year of 2000, when both Voyager spacecraft were in the supersonic solar wind region, and in 2012, when Voyager 1 observed traveling shocks. In the former case, Voyager observations themselves provide time- dependent boundary conditions in the solar wind. In the latter case, we use OMNI data at 1 AU to analyze the plasma and magnetic field behavior after Voyager 1 crossed the heliospheric boundary. Numerical results are compared with spacecraft observations. (paper)

  19. Interstellar turbulence and shock waves

    International Nuclear Information System (INIS)

    Bykov, A.M.

    1982-01-01

    Random deflections of shock fronts propagated through the turbulent interstellar medium can produce the strong electro-density fluctuations on scales l> or approx. =10 13 cm inferred from pulsar radio scintillations. The development of turbulence in the hot-phase ISM is discussed

  20. Experimental evidence and theoretical analysis of photoionized plasma under x-ray radiation produced by an intense laser

    International Nuclear Information System (INIS)

    Wang Feilu; Fujioka, Shinsuke; Nishimura, Hiroaki; Takabe, Hideaki; Kato, Daiji; Li Yutong; Zhao Gang; Zhang Jie

    2008-01-01

    Photoionized plasma was studied experimentally under laboratory conditions by means of high intensity short pulse lasers. The experiment consists of a gold cavity filled with nitrogen gas. Six laser beams were focused on the inner surface of the gold cavity, thereby generating an almost black-body radiation having temperature of 80 eV inside the cavity. This radiation heats the nitrogen gas mainly by means of photoionization. L-shell emissions from N V to N VII have been observed in the wavelength range between 90 and 200 A. A time-dependent Detailed Configuration Accounting computer program has been developed to analyze the experimental spectra. In contrast to standard analysis of astrophysical observations, the evidence for photoionization is inferred from the spectral lines ratios. Comparison between the experimental and simulated line spectra indicates that the radiation heated nitrogen attains temperature of 20-30 eV, much lower than the source radiation temperature. Paradoxically, it is also shown that similar line emissions can be reproduced computationally also when the radiation and plasma temperatures both equal approximately 60 eV. This misleading result indicates that experimental simulation in laboratory is sometimes necessary to avoid misinterpretation of astrophysical spectra.

  1. Collisionless electrostatic shocks

    DEFF Research Database (Denmark)

    Andersen, H.K.; Andersen, S.A.; Jensen, Vagn Orla

    1970-01-01

    An attempt was made in the laboratory to observe the standing collisionless electrostatic shocks in connection with the bow shock of the earth......An attempt was made in the laboratory to observe the standing collisionless electrostatic shocks in connection with the bow shock of the earth...

  2. Temporal properties of coherent synchrotron radiation produced by an electron bunch moving along an arc of a circle

    International Nuclear Information System (INIS)

    Geloni, G.; Saldin, E.L.; Schneidmiller, E.A.; Yurkov, M.V.

    2004-01-01

    In the limit for a large distance between bunch and detector and under the assumption that the entire process, i.e. radiation and detection, happens in vacuum, one can use the well-known Schwinger formulas in order to describe the single-particle radiation in the case of circular motion. Nevertheless, these formulas cannot be applied for particles moving in an arc of a circle. In this paper, we present a characterization of coherent synchrotron radiation (CSR) pulses in the time-domain as they are emitted by an electron bunch moving in an arc of a circle. This can be used in order to give a quantitative estimation of the effects of a finite bending magnet extension on the characteristics of the CSR pulse

  3. Improvement of antifungal and antibacterial antibiotic producing strain of Bacillus subtilis AFCI-69 by radiation and chemical mutagens. Part of a coordinated programme on radiation biology

    International Nuclear Information System (INIS)

    Ahmad, M.S.

    1978-08-01

    Gamma radiation was used to select higher antibiotic yield mutants of Bacillus subtilis AECL 69. The test organisms were Aspergillus niger RAGENI 70 and Staphylococcus aureus 6571 (16) N.C.T.C. Searches for fermentation, purification and characterization of antibiotics of parent strain and its mutants were carried out

  4. Anti-PD-1 Blockade and Stereotactic Radiation Produce Long-Term Survival in Mice With Intracranial Gliomas

    International Nuclear Information System (INIS)

    Zeng, Jing; See, Alfred P.; Phallen, Jillian; Jackson, Christopher M.; Belcaid, Zineb; Ruzevick, Jacob; Durham, Nicholas; Meyer, Christian; Harris, Timothy J.; Albesiano, Emilia; Pradilla, Gustavo; Ford, Eric; Wong, John; Hammers, Hans-Joerg; Mathios, Dimitris; Tyler, Betty; Brem, Henry; Tran, Phuoc T.; Pardoll, Drew; Drake, Charles G.

    2013-01-01

    Purpose: Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults, and radiation is one of the main treatment modalities. However, cure rates remain low despite best available therapies. Immunotherapy is a promising modality that could work synergistically with radiation, which has been shown to increase antigen presentation and promote a proinflammatory tumor microenvironment. Programmed-death-1 (PD-1) is a surface receptor expressed on activated and exhausted T cells, which mediate T cell inhibition upon binding with its ligand PD-L1, expressed on many tumor types including human GBMs. We tested the combination of anti-PD-1 immunotherapy with stereotactic radiosurgery in a mouse orthotopic GBM model. Methods and Materials: We performed intracranial implantation of mouse glioma cell line GL261 transfected with luciferase into C57BL/6 mice. Mice were stratified into 4 treatment groups: (1) control; (2) radiation only; (3) anti-PD-1 antibody only; and (4) radiation plus anti-PD-1 antibody. Overall survival was quantified. The mice were killed on day 21 after implantation to assess immunologic parameters in the brain/tumor, cervical lymph nodes, and spleen. Results: Improved survival was demonstrated with combination anti-PD-1 therapy plus radiation compared with either modality alone: median survival was 25 days in the control arm, 27 days in the anti-PD-1 antibody arm, 28 days in the radiation arm, and 53 days in the radiation plus anti-PD-1 therapy arm (P<.05 by log-rank Mantle-Cox). Long-term survival was seen only in the combined treatment arm, with a fraction (15%-40%) of animals alive at day 180+ after treatment. Immunologic data on day 21 after implantation showed increased tumor infiltration by cytotoxic T cells (CD8+/interferon-γ+/tumor necrosis factor-α+) and decreased regulatory T cells (CD4+/FOXP3) in the combined treatment group compared with the single modality arms. Conclusions: The combination of PD-1 blockade and localized

  5. Anti-PD-1 Blockade and Stereotactic Radiation Produce Long-Term Survival in Mice With Intracranial Gliomas

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Jing [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins Medical Institutes, Baltimore, Maryland (United States); See, Alfred P.; Phallen, Jillian; Jackson, Christopher M.; Belcaid, Zineb; Ruzevick, Jacob [Department of Neurosurgery, Johns Hopkins Medical Institutes, Baltimore, Maryland (United States); Durham, Nicholas [Department of Immunology, Johns Hopkins Medical Institutes, Baltimore, Maryland (United States); Meyer, Christian [Department of Oncology, Johns Hopkins Medical Institutes, Baltimore, Maryland (United States); Harris, Timothy J. [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins Medical Institutes, Baltimore, Maryland (United States); Albesiano, Emilia; Pradilla, Gustavo [Department of Neurosurgery, Johns Hopkins Medical Institutes, Baltimore, Maryland (United States); Ford, Eric; Wong, John [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins Medical Institutes, Baltimore, Maryland (United States); Hammers, Hans-Joerg [Department of Immunology, Johns Hopkins Medical Institutes, Baltimore, Maryland (United States); Mathios, Dimitris; Tyler, Betty; Brem, Henry [Department of Neurosurgery, Johns Hopkins Medical Institutes, Baltimore, Maryland (United States); Tran, Phuoc T. [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins Medical Institutes, Baltimore, Maryland (United States); Pardoll, Drew; Drake, Charles G. [Department of Immunology, Johns Hopkins Medical Institutes, Baltimore, Maryland (United States); and others

    2013-06-01

    Purpose: Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults, and radiation is one of the main treatment modalities. However, cure rates remain low despite best available therapies. Immunotherapy is a promising modality that could work synergistically with radiation, which has been shown to increase antigen presentation and promote a proinflammatory tumor microenvironment. Programmed-death-1 (PD-1) is a surface receptor expressed on activated and exhausted T cells, which mediate T cell inhibition upon binding with its ligand PD-L1, expressed on many tumor types including human GBMs. We tested the combination of anti-PD-1 immunotherapy with stereotactic radiosurgery in a mouse orthotopic GBM model. Methods and Materials: We performed intracranial implantation of mouse glioma cell line GL261 transfected with luciferase into C57BL/6 mice. Mice were stratified into 4 treatment groups: (1) control; (2) radiation only; (3) anti-PD-1 antibody only; and (4) radiation plus anti-PD-1 antibody. Overall survival was quantified. The mice were killed on day 21 after implantation to assess immunologic parameters in the brain/tumor, cervical lymph nodes, and spleen. Results: Improved survival was demonstrated with combination anti-PD-1 therapy plus radiation compared with either modality alone: median survival was 25 days in the control arm, 27 days in the anti-PD-1 antibody arm, 28 days in the radiation arm, and 53 days in the radiation plus anti-PD-1 therapy arm (P<.05 by log-rank Mantle-Cox). Long-term survival was seen only in the combined treatment arm, with a fraction (15%-40%) of animals alive at day 180+ after treatment. Immunologic data on day 21 after implantation showed increased tumor infiltration by cytotoxic T cells (CD8+/interferon-γ+/tumor necrosis factor-α+) and decreased regulatory T cells (CD4+/FOXP3) in the combined treatment group compared with the single modality arms. Conclusions: The combination of PD-1 blockade and localized

  6. GENERATION OF HIGH SHOCK PRESSURES BY LASER PULSES

    OpenAIRE

    Romain , J.

    1984-01-01

    Aspects of laser generated high shock pressures and results obtained over the last years are reviewed. Shock pressures up to 5 TPa inferred from shock velocity measurements are reported. Effects of laser wavelength, intensity and 2-D plasma expansion on the generated shock pressure are discussed. The hydrodynamic efficiency determined from various data including new results at 0,26 µm wavelength outlines the advantage of short wavelengths for producing very high pressures. The possibility of ...

  7. Shocking revelations

    International Nuclear Information System (INIS)

    Crum, L.A.; Matula, T.J.

    1997-01-01

    In single-bubble sonoluminescence (SBSL) a small gas bubble that has been acoustically levitated in a liquid driven into large amplitude volume oscillations by the sound fields, radiation visible light each and every acoustic cycle. These emissions could potentially lead to thermonuclear fusion. This paper reports on the background of SBSL, what the current research is, and what questions need to be answered in the future. 26 refs., 1 fig

  8. Shock, diaschisis and von Monakow

    Directory of Open Access Journals (Sweden)

    Eliasz Engelhardt

    2013-07-01

    Full Text Available The concept of shock apparently emerged in the middle of the 18th century (Whyett as an occurrence observed experimentally after spinal cord transection, and identified as "shock" phenomenon one century later (Hall. The concept was extended (Brown-Séquard and it was suggested that brain lesions caused functional rupture in regions distant from the injured one ("action à distance". The term "diaschisis" (von Monakow, proposed as a new modality of shock, had its concept broadened, underpinned by observations of patients, aiming at distinguishing between symptoms of focal brain lesions and transitory effects they produced, attributable to depression of distant parts of the brain connected to the injured area. Presently, diaschisis is related mainly to cerebrovascular lesions and classified according to the connection fibers involved, as proposed by von Monakow. Depression of metabolism and blood flow in regions anatomically separated, but related by connections with the lesion, allows observing diaschisis with neuroimaging.

  9. Installation And Test Of Electron Beam Generation System To Produce Far-Infrared Radiation And X-Ray Pulses

    International Nuclear Information System (INIS)

    Wichaisirimongkol, Pathom; Jinamoon, Witoon; Khangrang, Nopadon; Kusoljariyakul, Keerati; Rhodes, Michael W.; Rimjaem, Sakhorn; Saisut, Jatuporn; Chitrlada, Thongbai; Vilaithong, Thiraphat; Wiedemann, Helmut

    2005-10-01

    SURIYA project at the Fast Neutron Research Facility, Chiang Mai University, aims to establish a facility to generate femtosecond electron beams. This electron beam can be used to generate high intensity far-infrared radiation and ultra-short X-ray pulses. The main components of the system are a 3 MeV RF electron gun with a thermionic cathode, an a-magnet as a bunch compressor, and post acceleration 15-20 MeV by a linear accelerator (linac). Between the main components, there are focusing quadrupole magnets and steering magnets to maintain the electron beam within a high vacuum tube. At the end of the beam transport line, a dipole magnet has been installed to function as a beam dump and an energy spectrometer. After the installation and testing of individual major components were completed, we have been investigating the generation of the electron beam, intense far- infrared radiation and ultra short X-ray pulses

  10. Inactivation of carotenoid-producing and albino strains of Neurospora crassa by visible light, blacklight, and ultraviolet radiation

    International Nuclear Information System (INIS)

    Blanc, P.L.; Tuveson, R.W.; Sargent, M.L.

    1976-01-01

    Suspensions of Neurospora crassa conidia were inactivated by blacklight (BL) radiation (300 to 425 nm) in the absence of exogenous photosensitizing compounds. Carotenoid-containing wild-type conidia were less sensitive to BL radiation than albino conidia, showing a dose enhancement factor (DEF) of 1.2 for dose levels resulting in less than 10 percent survival. The same strains were about equally sensitive to shortwave ultraviolet (uv) inactivation. The kinetics of BL inactivation are similar to those of photodynamic inactivation by visible light in the presence of a photosensitizing dye (methylene blue). Only limited inactivation by visible light in the absence of exogenous photosensitizers was observed. BL and UV inactivations are probably caused by different mechanisms since wild-type conidia are only slightly more resistant to BL radiation (DEF = 1.2 at 1.0 percent survival) than are conidia from a uv-sensitive strain (upr-1, uvs-3). The BL-induced lethal lesions are probably not cyclobutyl pyrimidine dimers since BL-inactivated Haemophilus influenzae transforming deoxyribonucleic acid is not photoreactivated by N. crassa wild-type enzyme extracts, whereas uv-inactivated transforming deoxyribonucleic acid is photoreactivable with this treatment

  11. Ultrastructural changes produced in Ehrlich ascites carcinoma cells by ultraviolet-visible radiation in the presence of melanins

    Energy Technology Data Exchange (ETDEWEB)

    Lea, P.J.; Pawlowski, A.; Persad, S.D.; Menon, I.A.; Haberman, H.F.

    1988-01-01

    Irradiation of Ehrlich ascites carcinoma (EAC) cells in the presence of pheomelanin, i.e., red hair melanin (RHM), has been reported to produce extensive cell lysis. Irradiation in the presence of eumelanin, i.e., black hair melanin (BHM), or irradiation in the absence of either type of melanin did not produce this effect. We observed that RHM particles penetrated the cell membrane without apparent structural damage to the cell or the cell membrane. Irradiation of the cells in the absence of melanin did not produce any changes in the ultrastructure of the cells. Incubation of the cells in the dark in the presence of RHM produced only minor structural, mainly cytoplasmic changes. Irradiation of the cells in the presence of RHM produced extensive ultrastructural changes prior to complete cell lysis; these changes were more severe than the effects of incubation of the cells in the dark in the presence of RHM. When the cells incubated in the dark or irradiated in the presence of latex particles or either one of the eumelanins particles, viz. BHM or synthetic dopa melanin, these particles did not penetrate into the cells or produce any ultrastructural changes. These particles were in fact not even ingested by the cells.

  12. Shock diffraction in alumina powder

    International Nuclear Information System (INIS)

    Venz, G.; Killen, P.D.; Page, N.W.

    1996-01-01

    In order to produce complex shaped components by dynamic compaction of ceramic powders detailed knowledge of their response under shock loading conditions is required. This work attempts to provide data on release effects and shock attenuation in 1 μm and 5 μm α-alumina powders which were compacted to between 85 % and 95 % of the solid phase density by the impact of high velocity steel projectiles. As in previous work, the powder was loaded into large cylindrical dies with horizontal marker layers of a contrasting coloured powder to provide a record of powder displacement in the recovered specimens. After recovery and infiltration with a thermosetting resin the specimens were sectioned and polished to reveal the structure formed by the passage of the projectile and shock wave. Results indicate that the shock pressures generated were of the order of 0.5 to 1.4 GPa and higher, with shock velocities and sound speeds in the ranges 650 to 800 m/s and 350 to 400 m/s respectively

  13. Shocked plate metal atom oxidation laser

    International Nuclear Information System (INIS)

    De Koker, J.G.; Rice, W.W. Jr.; Jensen, R.J.

    1975-01-01

    A method and apparatus for producing metal atom oxidation lasing wherein an explosively shocked grooved metal plate produces metal vapor jets directed through an appropriate gaseous oxidizer are described. Reaction of the metal vapor with the oxidizer produces molecular species having a population inversion therein. (U.S.)

  14. Shock-wave induced mechanoluminescence: A new technique for studying effects of shock pressure on crystals

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, B.P.; Parganiha, S.; Sonwane, V.D. [School of Studies in Physics and Astrophysics, Pt. Ravishankar Shukla University, Raipur 492010, Chhattisgarh (India); Chandra, V.K. [Department of Electrical and Electronics Engineering, Chhatrapati Shivaji Institute of Technology, Shivaji Nagar, Kolihapuri, Durg 491001, Chhattisgarh (India); Jha, Piyush, E-mail: piyushjha22@rediffmail.com [Department of Applied Physics, Raipur Institute of Technology, Chhatauna, Mandir Hasuad, Raipur 492101, Chhattisgarh (India); Baghel, R.N. [School of Studies in Physics and Astrophysics, Pt. Ravishankar Shukla University, Raipur 492010, Chhattisgarh (India)

    2016-10-15

    The impact of a projectile propelled to velocities in the range of 0.5–2.5 km/s on to a target (X-cut quartz crystal) produces shock waves travelling at velocity of nearly 10 km/s in target, in which intense mechanoluminescence (ML) pulses of microsecond duration are produced, both in compression and post-compression conditions. The piezoelectric field produced due to surface charges of fractured target, causes band bending and subsequently, the free charge carriers are generated in the respective bands and the emission of ML occurs. The ML appears after a delay time t{sub th} whose value decreases with increasing value of the shock pressure. Initially, the ML intensity increases with the shock pressure because of the creation of more surfaces; however, for higher values of the shock pressure, the ML intensity tends to attain a saturation value because of the hardening of the crystals due to the creation of small crystallites in which the creation of new surfaces becomes difficult. The ratio between peak ML intensity in the uncompressed region and the maximum ML intensity in the compressed region decreases with increasing shock pressure because more defects produced at high pressure generate higher barrier for the relaxation of blocked cracks under compression. The expressions derived for characteristics of shock-induced ML are able to explain satisfactorily the experimental results. Shock-wave velocity, shock pressure, transit time, lifetime of electrons in conduction band, etc. can be determined by the shock-induced ML.As such, the shock-induced ML provides a new optical technique for the studies of materials under shock pressure.

  15. Collisionless Weibel shocks: Full formation mechanism and timing

    Energy Technology Data Exchange (ETDEWEB)

    Bret, A. [ETSI Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Instituto de Investigaciones Energéticas y Aplicaciones Industriales, Campus Universitario de Ciudad Real, 13071 Ciudad Real (Spain); Stockem, A. [GoLP/Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisbon (Portugal); Institut für Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Narayan, R. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-51 Cambridge, Massachusetts 02138 (United States); Silva, L. O. [GoLP/Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisbon (Portugal)

    2014-07-15

    Collisionless shocks in plasmas play an important role in space physics (Earth's bow shock) and astrophysics (supernova remnants, relativistic jets, gamma-ray bursts, high energy cosmic rays). While the formation of a fluid shock through the steepening of a large amplitude sound wave has been understood for long, there is currently no detailed picture of the mechanism responsible for the formation of a collisionless shock. We unravel the physical mechanism at work and show that an electromagnetic Weibel shock always forms when two relativistic collisionless, initially unmagnetized, plasma shells encounter. The predicted shock formation time is in good agreement with 2D and 3D particle-in-cell simulations of counterstreaming pair plasmas. By predicting the shock formation time, experimental setups aiming at producing such shocks can be optimised to favourable conditions.

  16. Shock formation within sonoluminescence bubbles

    International Nuclear Information System (INIS)

    Vuong, V.Q.; Szeri, A.J.; Young, D.A.

    1999-01-01

    A strong case has been made by several authors that sharp, spherically symmetric shocks converging on the center of a spherical bubble driven by a strong acoustic field give rise to rapid compression and heating that produces the brief flash of light known as sonoluminescence. The formation of such shocks is considered. It is found that, although at the main collapse the bubble wall does indeed launch an inwardly-traveling compression wave, and although the subsequent reflection of the wave at the bubble center produces a very rapid temperature peak, the wave is prevented from steepening into a sharp shock by an adverse gradient in the sound speed caused by heat transfer. It is shown that the mathematical characteristics of the flow can be prevented from accumulating into a shock front by this adverse sound speed gradient. A range of results is presented for a variety of bubble ambient radii and sound field amplitudes suggested by experiments. The time scale of the peak temperature in the bubble is set by the dynamics of the compression wave: this is typically in the range 100 - 300 ps (FWHM) in concert with recent measurements of the sonoluminescence pulse width. copyright 1999 American Institute of Physics

  17. Towards producing novel fish gelatin films by combination treatments of ultraviolet radiation and sugars (ribose and lactose) as cross-linking agents.

    Science.gov (United States)

    Bhat, Rajeev; Karim, A A

    2014-07-01

    Developing novel fish gelatin films with better mechanical properties than mammalian gelatin is a challenging but promising endeavor. Studies were undertaken to produce fish gelatin films by combining treatments with different sugars (ribose and lactose) followed 'by' 'and' ultraviolet (UV) radiation, as possible cross-linking agents. Increase in tensile strength and percent elongation at break was recorded, which was more significant in films without sugars that were exposed to UV radiation. Films with added ribose showed decreased solubility after UV treatment and exhibited higher swelling percentage than films with added lactose, which readily dissolved in water. FTIR spectra of all the films showed identical patterns, which indicated no major changes to have occurred in the functional groups as a result of interaction between gelatin, sugars and UV irradiation. The results of this study could be explored for commercial use, depending on industrial needs for either production of edible films or for food packaging purposes.

  18. Shock-induced devolatilization of calcite

    Science.gov (United States)

    Boslough, M. B.; Ahrens, T. J.; Vizgirda, J.; Becker, R. H.; Epstein, S.

    1982-01-01

    Experimental measurements of the release adiabats by Vizgirda (1981) indicate that substantial vaporization takes place upon release from shock pressures of 37 GPa for calcite and 14 GPa for aragonite. The present investigation includes the first controlled partial vaporization experiments on calcite. The experiments were conducted to test the predictions of the release adiabat experiments. The quantities of the gaseous species produced from shocked calcite and their carbon and oxygen isotopic compositions were determined, and the shock-induced effect on the Mn(2+) electron spin resonance spectrum in the shock-recovered calcite was observed. On the basis of the obtained results, it is concluded that shock stresses at the 17-18 GPa level give rise to volatilization of 0.03-0.3 (mole) percent of calcite to CO2 and CO. The devolatilization of calcite occurs at low pressure at significantly lower entropy densities than predicted on the basis of thermodynamic continuum models.

  19. Gamma radiation effects on the structure of the sex pheromone producing gland in the female Trogoderma Granarium Everts

    International Nuclear Information System (INIS)

    Gharib, O.H.; Elnaggar, S.E.M.; Abdelkawy, F.K.

    1993-01-01

    Effect of gamma irradiation on the structure of the sex pheromone producing gland in 2-day-old females, Trogoderma Granarium Everts was investigated. With the sub sterilizing doses 20 and 40 Gray, the structure started to be destroyed and became undistinguished as well as the sterilizing dose 60 Gray caused complete damage and the glandular tissue appeared as a narrow ribbon. 4 fig

  20. Measurements of the equations of state and spectrum of nonideal xenon plasma under shock compression

    International Nuclear Information System (INIS)

    Zheng, J.; Gu, Y. J.; Chen, Z. Y.; Chen, Q. F.

    2010-01-01

    Experimental equations of state on generation of nonideal xenon plasma by intense shock wave compression was presented in the ranges of pressure of 2-16 GPa and temperature of 31-50 kK, and the xenon plasma with the nonideal coupling parameter Γ range from 0.6-2.1 was generated. The shock wave was produced using the flyer plate impact and accelerated up to ∼6 km/s with a two-stage light gas gun. Gaseous specimens were shocked from two initial pressures of 0.80 and 4.72 MPa at room temperature. Time-resolved spectral radiation histories were recorded by using a multiwavelength channel pyrometer. The transient spectra with the wavelength range of 460-700 nm were recorded by using a spectrometer to evaluate the shock temperature. Shock velocity was measured and particle velocity was determined by the impedance matching methods. The equations of state of xenon plasma and ionization degree have been discussed in terms of the self-consistent fluid variational theory.

  1. Measurements of the equations of state and spectrum of nonideal xenon plasma under shock compression

    Science.gov (United States)

    Zheng, J.; Gu, Y. J.; Chen, Z. Y.; Chen, Q. F.

    2010-08-01

    Experimental equations of state on generation of nonideal xenon plasma by intense shock wave compression was presented in the ranges of pressure of 2-16 GPa and temperature of 31-50 kK, and the xenon plasma with the nonideal coupling parameter Γ range from 0.6-2.1 was generated. The shock wave was produced using the flyer plate impact and accelerated up to ˜6km/s with a two-stage light gas gun. Gaseous specimens were shocked from two initial pressures of 0.80 and 4.72 MPa at room temperature. Time-resolved spectral radiation histories were recorded by using a multiwavelength channel pyrometer. The transient spectra with the wavelength range of 460-700 nm were recorded by using a spectrometer to evaluate the shock temperature. Shock velocity was measured and particle velocity was determined by the impedance matching methods. The equations of state of xenon plasma and ionization degree have been discussed in terms of the self-consistent fluid variational theory.

  2. Irradiation studies of local Streptomyces strains for higher antibiotic producing capacity. Part of a coordinated programme on radiation microbiology

    International Nuclear Information System (INIS)

    Kintanar, Q.L.

    1978-06-01

    The 14 mutants produced by sequential exposure to gamma and ultraviolet irradiation were found to belong to different fundamental types of variants differing in morphology, stability, and metabolite spectra from the parent strain. The first hour mutants, M-1 to M-4 could be considered as belonging to the first category of mutants. Metabolites produced were the same as the parent but differ only in quantity. One was a morphological mutant, M-4 which differed from the parent strain in the production of a brown pigment and conidia, and lack of aerial mycelium. It was found to be most stable and capable of producing high antibiotic yield. The rest of the mutants, M-5 to M-14 could be grouped in the second category. The synthesis of one or more metabolites of the parent strain has been lost by mutation. Unexpectedly, a mutant, M-9 instead of synthesizing either oxytetracycline or tetracycline produced chlortetracycline. Coconut water was found inhibitory to the production of antibiotics by the parent strain and the high and low producing mutants. Modifying the medium by incorporating phosphate and adjusting the initial pH to 4.75 raised the antibiotic yield of the 10% coconut water supplemented medium of M-4 more than the control. Higher pH than the optimum shortened the lag phase but reduced the antibiotic yield while a lower initial pH prevented the growth of the organism giving negligible yield. A reduction of pH to pH 4.5 for the initial 48 hours lengthened the lag phase with almost no adverse effect on the yield. The incorporation of large amounts of coconut water aggravated the amino acid imbalance of the medium

  3. Grain Destruction in a Supernova Remnant Shock Wave

    Science.gov (United States)

    Raymond, John C.; Ghavamian, Parviz; Williams, Brian J.; Blair, William P.; Borkowski, Kazimierz J.; Gaetz, Terrance J.; Sankrit, Ravi

    2014-01-01

    Dust grains are sputtered away in the hot gas behind shock fronts in supernova remnants, gradually enriching the gas phase with refractory elements. We have measured emission in C IV (lambda)1550 from C atoms sputtered from dust in the gas behind a non-radiative shock wave in the northern Cygnus Loop. Overall, the intensity observed behind the shock agrees approximately with predictions from model calculations that match the Spitzer 24 micron and the X-ray intensity profiles. Thus these observations confirm the overall picture of dust destruction in SNR shocks and the sputtering rates used in models. However, there is a discrepancy in that the CIV intensity 10'' behind the shock is too high compared to the intensities at the shock and 25'' behind it. Variations in the density, hydrogen neutral fraction and the dust properties over parsec scales in the pre- shock medium limit our ability to test dust destruction models in detail.

  4. On possible structures of transverse ionizing shock waves

    International Nuclear Information System (INIS)

    Liberman, M.A.; Velikovich, A.L.

    1978-01-01

    The possible structures of ionizing shock waves propagating in gases across the magnetic field are investigated taking account of both ionization kinetics and the non-isothermality of the plasma which is formed within the shock front. It is shown that a definite factor in shaping the structure of the transverse ionizing shock wave is photo-ionization of the neutral gas across the front. The paper includes a study of the evolution of the transverse ionizing shock front with regard to photo-ionization, disclosing that a stable stationary shock structure emerges only in boundary conditions which are close to magnetohydrodynamic ones, i.e. upsilon 1 H 1 = upsilon 2 H 2 . In the case of strong transverse ionizing shock waves, when the flux of ionizing radiation across the front is great, the shock structure is obviously magnetohydrodynamic. (author)

  5. The impact of energy price shocks on the UK economy

    International Nuclear Information System (INIS)

    2007-01-01

    This report describes the results of six scenarios considering the impact of energy price shocks on the UK economy. The six scenarios considered are: UK aggregate energy price scenario; pan-Europe aggregate energy price; global aggregate energy price; UK temporary gas price; UK permanent gas price; crude (Brent) oil price. As expected, shocks to aggregate energy prices cause the largest macroeconomic and energy demand effects (in terms of growth rate volatility). Shocks to gas prices produce a greater growth volatility for macroeconomic and energy demand than shocks to oil prices. In general terms, shocks specific to the UK market tend to produce more growth rate volatility than wider ranging price shocks (global or pan-European). All of the price shocks considered have a recursive effect on the main indicators, which tend to stabilise around the baseline level in the long run. The report summarises the results obtained in the different scenarios

  6. Are Credit Shocks Supply or Demand Shocks?

    OpenAIRE

    Bijapur, Mohan

    2013-01-01

    This paper provides new insights into the relationship between the supply of credit and the macroeconomy. We present evidence that credit shocks constitute shocks to aggregate supply in that they have a permanent effect on output and cause inflation to rise in the short term. Our results also suggest that the effects on aggregate supply have grown stronger in recent decades.

  7. Interaction of Interstellar Shocks with Dense Obstacles: Formation of ``Bullets''

    Science.gov (United States)

    Gvaramadze, V. V.

    The so-called cumulative effect take place in converging conical shock waves arising behind dense obstacles overtaken by incident interstellar shock. A significant part of energy of converging flow of matter swept-up by a radiative conical shock can be transferred to a dense jet-like ejection (``bullet'') directed along the cone axis. Possible applications of this effect for star-forming regions (e.g., OMC-1) and supernova remnants (e.g., Vela SNR) are discussed.

  8. Shock absorbing structure

    International Nuclear Information System (INIS)

    Kojima, Naoki; Matsushita, Kazuo.

    1992-01-01

    Small pieces of shock absorbers are filled in a space of a shock absorbing vessel which is divided into a plurality of sections by partitioning members. These sections function to prevent excess deformation or replacement of the fillers upon occurrence of falling accident. Since the shock absorbing small pieces in the shock absorbing vessel are filled irregularly, shock absorbing characteristics such as compression strength is not varied depending on the direction, but they exhibit excellent shock absorbing performance. They surely absorb shocks exerted on a transportation vessel upon falling or the like. If existing artificial fillers such as pole rings made of metal or ceramic and cut pieces such as alumium extrusion molding products are used as the shock absorbing pieces, they have excellent fire-proofness and cold resistance since the small pieces are inflammable and do not contain water. (T.M.)

  9. Melting under shock compression

    International Nuclear Information System (INIS)

    Bennett, B.I.

    1980-10-01

    A simple model, using experimentally measured shock and particle velocities, is applied to the Lindemann melting formula to predict the density, temperature, and pressure at which a material will melt when shocked from room temperature and zero pressure initial conditions

  10. The shielding against radiation produced by powder metallurgy with tungsten copper alloy applied on transport equipment for radio-pharmaceutical products

    International Nuclear Information System (INIS)

    Cione, Francisco C.; Sene, Frank F.; Souza, Armando C. de; Betini, Evandro G.; Rossi, Jesualdo L.; Rizzuto, Marcia A.

    2015-01-01

    Safety is mandatory on medicine radiopharmaceutical transportation and dependent on radiation shielding material. The focus of the present work is to minimize the use of harmful materials as lead and depleted uranium usually used in packages transportation. The tungsten-copper composite obtained by powder metallurgy (PM) is non-toxic. In powder metallurgy the density and the porosity of the compacted parts depends basically upon particle size distribution of each component, mixture, compacting pressure and sintering temperature cycle. The tungsten-copper composite, when used for shielding charged particles, X-rays, gamma photons or other photons of lower energy require proper interpretation of the radiation transport phenomena. The radioactive energy reduction varies according to the porosity and density of the materials used as shielding. The main factor for radiation attenuation is the cross section value for tungsten. The motivation research factor is an optimization of the tungsten and cooper composition in order to achieve the best linear absorption coefficient given by equation I (x) = I 0 e (-ux) . Experiments were conducted to quantify the effective radiation shielding properties of tungsten-copper composite produced by PM, varying the cooper amount in the composite. The studied compositions were 15%, 20% and 25% copper in mass. The Compaction pressure was 270 MPa and the sintering atmosphere was in 1.1 atm in N 2 +H 2 . The sintering temperature was 980 deg C for 2 h. The linear absorption coefficient factor was similar either for the green and the sintered compacts, due the amount of porosity did not affect the radiation attenuation. Thus the sintered was meant for size reduction and mechanical properties enhancement. (author)

  11. The shielding against radiation produced by powder metallurgy with tungsten copper alloy applied on transport equipment for radio-pharmaceutical products

    Energy Technology Data Exchange (ETDEWEB)

    Cione, Francisco C.; Sene, Frank F.; Souza, Armando C. de; Betini, Evandro G.; Rossi, Jesualdo L., E-mail: fceoni@hotmail.com, E-mail: ffsene@hotmail.com, E-mail: armandocirilo@yahoo.com, E-mail: evandrobetini@gmail.com, E-mail: jelrossi@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Rizzuto, Marcia A., E-mail: marizzutto@if.usp.br [Universidade de Sao Paulo (IF/USP), SP (Brazil). Instituto de Fisica

    2015-07-01

    Safety is mandatory on medicine radiopharmaceutical transportation and dependent on radiation shielding material. The focus of the present work is to minimize the use of harmful materials as lead and depleted uranium usually used in packages transportation. The tungsten-copper composite obtained by powder metallurgy (PM) is non-toxic. In powder metallurgy the density and the porosity of the compacted parts depends basically upon particle size distribution of each component, mixture, compacting pressure and sintering temperature cycle. The tungsten-copper composite, when used for shielding charged particles, X-rays, gamma photons or other photons of lower energy require proper interpretation of the radiation transport phenomena. The radioactive energy reduction varies according to the porosity and density of the materials used as shielding. The main factor for radiation attenuation is the cross section value for tungsten. The motivation research factor is an optimization of the tungsten and cooper composition in order to achieve the best linear absorption coefficient given by equation I{sub (x)} = I{sub 0}e{sup (-ux)}. Experiments were conducted to quantify the effective radiation shielding properties of tungsten-copper composite produced by PM, varying the cooper amount in the composite. The studied compositions were 15%, 20% and 25% copper in mass. The Compaction pressure was 270 MPa and the sintering atmosphere was in 1.1 atm in N{sub 2}+H{sub 2}. The sintering temperature was 980 deg C for 2 h. The linear absorption coefficient factor was similar either for the green and the sintered compacts, due the amount of porosity did not affect the radiation attenuation. Thus the sintered was meant for size reduction and mechanical properties enhancement. (author)

  12. Computed tomography for light materials using a monochromatic X-ray beam produced by parametric X-ray radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hayakawa, Y., E-mail: yahayak@lebra.nihon-u.ac.jp [Laboratory for Electron Beam Research and Application, Nihon University, Narashinodai 7-24-1, Funabashi 274-8501 (Japan); Hayakawa, K.; Inagaki, M. [Laboratory for Electron Beam Research and Application, Nihon University, Narashinodai 7-24-1, Funabashi 274-8501 (Japan); Kaneda, T. [Nihon University School of Dentistry at Matsudo, Sakaecho-Nishi 2-870-1, Matsudo 271-8587 (Japan); Nakao, K.; Nogami, K. [Laboratory for Electron Beam Research and Application, Nihon University, Narashinodai 7-24-1, Funabashi 274-8501 (Japan); Sakae, T. [Nihon University School of Dentistry at Matsudo, Sakaecho-Nishi 2-870-1, Matsudo 271-8587 (Japan); Sakai, T.; Sato, I. [Laboratory for Electron Beam Research and Application, Nihon University, Narashinodai 7-24-1, Funabashi 274-8501 (Japan); Takahashi, Y. [Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Oho, Tsukuba 305-8501 (Japan); Tanaka, T. [Laboratory for Electron Beam Research and Application, Nihon University, Narashinodai 7-24-1, Funabashi 274-8501 (Japan)

    2013-08-15

    Computed tomography (CT) for light materials such as soft biological tissues was performed using a monochromatic X-ray beam provided by a parametric X-ray radiation (PXR) source at the Laboratory for Electron Beam Research and Application (LEBRA) of Nihon University. Using a high-efficiency flat panel detector (FPD), each projection image for CT was taken with exposure times of 5 or 10 s, and 60–360 projection images in each run were obtained with total measurement time of 5 min to 1 h. CT images were obtained from the projection images using the conventional calculation method. The typical tomograms obtained had sharp outlines, which are likely attributable to the propagation-based phase contrast.

  13. An amplitude analysis of the K bar K and π+π- systems (M 2) produced in J/ψ radiative decay

    International Nuclear Information System (INIS)

    Chen, Liang-Ping

    1991-10-01

    A mass independent amplitude of the K bar K and π + π - systems (M 2 ) produced in J/ψ radiative decay is presented. For the first time a large spin zero component in the θ(1720) mass region is observed, with all data samples analyzed. A small amount of spin two component in this mass region for the K bar K data samples is not ruled out with the present statistics. This study reveals, also for the first time, the production of the f o (1400) in the π + π - channel, and refines previous measurements of the f 2 (1270) and f' 2 (1525). 13 refs., 2 figs., 2 tabs

  14. Characterization of Chitosan Produced from Fermented Shrimp Shell Waste by Bacillus subtilis NA12 Using Gamma Radiation

    International Nuclear Information System (INIS)

    Bashandy, A.S.; Raffat, E.A.; Ibrahim, H.M.M.; El Tayeb, T.S.; Gamal, R.F.

    2017-01-01

    This study focused on characterization of chitosan obtained in a previous study from fermented shrimp shell waste (SSW) by Bacillus subtilis NA12. Extracted chitin was exposed to different gamma radiation doses (5-35 kGy). The molecular weight of the resultant chitosan decreased constantly with increasing radiation dose from 1.9 × 10"6 (g/mol) (non-irradiated) to 3.7 ×10"4 (g/mol) (at 35 kGy). The degree of deacetylation (DDA %) was determined by using potentiometric titration. The structural properties of chitin and chitosan were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), and thermogravimetric analysis (TGA). The prepared chitosan has higher solubility and DDA % compared to the standard chitosan. FT-IR analysis clearly confirmed the successful extraction of pure chitin and chitosan. TGA showed that chitin exhibited a stable structure toward thermal decomposition than chitosan. XRD analysis revealed that extracted chitin was more crystalline than prepared chitosan. Chitosan with different molecular weights was evaluated as an antibacterial agent against representative pathogenic bacterial strains. Chitosan obtained at 35 kGy, with molecular weight 3.7×10"4 (g/mol ) and DDA of 87.9 %, showed the highest antimicrobial activity against Escherichia coli, Klebsiella sp., Staphylococcus aureus and Pseudomonas aeruginosa. It revealed inhibition zone diameter of 5.4 ± 0.2, 5.4 ± 0.12, 3.5 ± 0.21 and 1.4 ± 0.06 cm, respectively

  15. On possible structures of normal ionizing shock waves in electromagnetic shock tubes

    International Nuclear Information System (INIS)

    Liberman, M.A.; Synakh, V.S.; Zakajdakhov, V.V.; Velikovich, A.L.

    1982-01-01

    The problem of possible structures of normal ionizing shock waves is studied. On the basis of the general theory of ionizing shock waves in magnetic fields, a similarity solution of the piston problem for an impenetrable piston and a magnetic piston is described and a numerical solution of the non-stationary piston problem is obtained. It is shown that precursor photo-ionization of the neutral gas by the radiation of the shock-heated gas is the dominant factor in shaping normal ionizing shock structures. In particular, it is shown that the strong overheating of atoms and ions in shock fronts is due to the tensor form of Ohm's law in the precursor region. (author)

  16. Relativistic Shock Acceleration

    International Nuclear Information System (INIS)

    Duffy, P.; Downes, T.P.; Gallant, Y.A.; Kirk, J.G.

    1999-01-01

    In this paper we briefly review the basic theory of shock waves in relativistic hydrodynamics and magneto-hydrodynamics, emphasising some astrophysically interesting cases. We then present an overview of the theory of particle acceleration at such shocks describing the methods used to calculate the spectral indices of energetic particles. Recent results on acceleration at ultra-relativistic shocks are discussed. (author)

  17. Radiations

    International Nuclear Information System (INIS)

    Pujol Mora, J.

    1999-01-01

    The exposition to ionizing radiations is a constant fact in the life of the human being and its utilization as diagnostic and therapeutic method is generalized. However, it is notorious how as years go on, the fear to the ionizing radiation seems to persist too, and this fact is not limited to the common individual, but to the technical personnel and professional personnel that labors with them same. (S. Grainger) [es

  18. Radiation

    International Nuclear Information System (INIS)

    Davidson, J.H.

    1986-01-01

    The basic facts about radiation are explained, along with some simple and natural ways of combating its ill-effects, based on ancient healing wisdom as well as the latest biochemical and technological research. Details are also given of the diet that saved thousands of lives in Nagasaki after the Atomic bomb attack. Special comment is made on the use of radiation for food processing. (U.K.)

  19. Generation of high shock pressures by laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Romain, J.P. (GRECO ILM, Laboratoire d' Energetique et Detonique, E.N.S.M.A., 86 - Poitiers (France))

    1984-11-01

    Aspects of laser generated high shock pressures and results obtained over the last years are reviewed. Shock pressures up to 5 TPa inferred from shock velocity measurements are reported. Effects of laser wavelength, intensity and 2-D plasma expansion on the generated shock pressure are discussed. The hydrodynamic efficiency determined from various data including new results at 0,26 ..mu..m wavelength outlines the advantage of short wavelengths for producing very high pressures. The possibility of achieving shock pressures in the 10 TPa range with the use of the impedance match technique is examined.

  20. Generation of high shock pressures by laser pulses

    International Nuclear Information System (INIS)

    Romain, J.P.

    1984-01-01

    Aspects of laser generated high shock pressures and results obtained over the last years are reviewed. Shock pressures up to 5 TPa inferred from shock velocity measurements are reported. Effects of laser wavelength, intensity and 2-D plasma expansion on the generated shock pressure are discussed. The hydrodynamic efficiency determined from various data including new results at 0,26 μm wavelength outlines the advantage of short wavelengths for producing very high pressures. The possibility of achieving shock pressures in the 10 TPa range with the use of the impedance match technique is examined

  1. Magnetohydrodynamic shocks in molecular clouds

    International Nuclear Information System (INIS)

    Chernoff, D.F.

    1985-01-01

    Part one develops the mathematical and physical theory of one-dimensional, time-independent subalfvenic flow in partially ionized gas with magnetic fields, for application to shocks in molecular clouds. Unlike normal gas-dynamic shocks, the neutral flow may be continuous and cool if the gas radiates efficiently and does not self-ionize. Analytic solutions are given in the limit that the neutral gas is either adiabatic or isothermal (cold). Numerical techniques are developed and applied to find the neutral flow under general circumstances. Part two extends the theory and results of part one in three ways: (1) to faster, superalfvenic flow, (2) to complex gases containing heavy charged particles (grains) in addition to ions, containing heavy charged particles (grains) in addition to ions, electrons and neutrals, and (3) to the entire range in (Omega tau), the ratio of charged particle damping time to gyroperiod, expected in gas flows in molecular clouds

  2. Cosmic Rays Accelerated at Cosmological Shock Waves Renyi Ma1 ...

    Indian Academy of Sciences (India)

    Cosmic Rays Accelerated at Cosmological Shock Waves. Renyi Ma1,2,∗ ... ratio of CR to thermal energy in the ICM and WHIM based on numerical simulations and diffusive shock ... Hence, the nonthermal radiation of CRs may provide us a.

  3. Radiation

    International Nuclear Information System (INIS)

    Winther, J.F.; Ulbak, K.; Dreyer, L.; Pukkala, E.; Oesterlind, A.

    1997-01-01

    Exposure to solar and ionizing radiation increases the risk for cancer in humans. Some 5% of solar radiation is within the ultraviolet spectrum and may cause both malignant melanoma and non-melanocytic skin cancer; the latter is regarded as a benign disease and is accordingly not included in our estimation of avoidable cancers. Under the assumption that the rate of occurrence of malignant melanoma of the buttocks of both men and women and of the scalp of women would apply to all parts of the body in people completely unexposed to solar radiation, it was estimated that approximately 95% of all malignant melanomas arising in the Nordic populations around the year 2000 will be due to exposure to natural ultraviolet radiation, equivalent to an annual number of about 4700 cases, with 2100 in men and 2600 in women, or some 4% of all cancers notified. Exposure to ionizing radiation in the Nordic countries occurs at an average effective dose per capita per year of about 3 mSv (Iceland, 1.1 mSv) from natural sources, and about 1 mSv from man-made sources. While the natural sources are primarily radon in indoor air, natural radionuclides in food, cosmic radiation and gamma radiation from soil and building materials, the man-made sources are dominated by the diagnostic and therapeutic use of ionizing radiation. On the basis of measured levels of radon in Nordic dwellings and associated risk estimates for lung cancer derived from well-conducted epidemiological studies, we estimated that about 180 cases of lung cancer (1% of all lung cancer cases) per year could be avoided in the Nordic countries around the year 2000 if indoor exposure to radon were eliminated, and that an additional 720 cases (6%) could be avoided annually if either radon or tobacco smoking were eliminated. Similarly, it was estimated that the exposure of the Nordic populations to natural sources of ionizing radiation other than radon and to medical sources will each give rise to an annual total of 2120

  4. Fundamentals of Non-relativistic Collisionless Shock Physics: IV. Quasi-Parallel Supercritical Shocks

    OpenAIRE

    Treumann, R. A.; Jaroschek, C. H.

    2008-01-01

    1. Introduction, 2. The (quasi-parallel) foreshock; Ion foreshock, Ion foreshock boundary region; Diffuse ions;Low-frequency upstream waves; Ion beam waves; The expected wave modes; Observations; Diffuse ion waves; Electron foreshock; Electron beams; Langmuir waves; stability of the electron beam; Electron foreshock boundary waves; Nature of electron foreshock waves; Radiation; Observations; Interpretation; 3. Quasi-parallel shock reformation; Low-Mach number quasi-parallel shocks; Turbulent ...

  5. Effect of Chromatin Structure on the Extent and Distribution of DNA Double Strand Breaks Produced by Ionizing Radiation; Comparative Study of hESC and Differentiated Cells Lines.

    Science.gov (United States)

    Venkatesh, Priyanka; Panyutin, Irina V; Remeeva, Evgenia; Neumann, Ronald D; Panyutin, Igor G

    2016-01-02

    Chromatin structure affects the extent of DNA damage and repair. Thus, it has been shown that heterochromatin is more protective against DNA double strand breaks (DSB) formation by ionizing radiation (IR); and that DNA DSB repair may proceed differently in hetero- and euchromatin regions. Human embryonic stem cells (hESC) have a more open chromatin structure than differentiated cells. Here, we study the effect of chromatin structure in hESC on initial DSB formation and subsequent DSB repair. DSB were scored by comet assay; and DSB repair was assessed by repair foci formation via 53BP1 antibody staining. We found that in hESC, heterochromatin is confined to distinct regions, while in differentiated cells it is distributed more evenly within the nuclei. The same dose of ionizing radiation produced considerably more DSB in hESC than in differentiated derivatives, normal human fibroblasts; and one cancer cell line. At the same time, the number of DNA repair foci were not statistically different among these cells. We showed that in hESC, DNA repair foci localized almost exclusively outside the heterochromatin regions. We also noticed that exposure to ionizing radiation resulted in an increase in heterochromatin marker H3K9me3 in cancer HT1080 cells, and to a lesser extent in IMR90 normal fibroblasts, but not in hESCs. These results demonstrate the importance of chromatin conformation for DNA protection and DNA damage repair; and indicate the difference of these processes in hESC.

  6. Induction of thermal shock proteins and changes in radiosensitivity after heat treatment of Bombyx mori L. embryos

    International Nuclear Information System (INIS)

    Agaev, F.A.

    1993-01-01

    The method of gel-electrophoresis was used to study thermal shock protein synthesis in Bombyx mori embryos exposed to a mixture of heat and gamma-radiation. Induction of thermal shock protein synthesis was not inhibited by gamma-radiation. It is suggested that thermal shock proteins are involved embryo radiosensitivity modification

  7. Free radical production by high energy shock waves--comparison with ionizing irradiation.

    Science.gov (United States)

    Morgan, T R; Laudone, V P; Heston, W D; Zeitz, L; Fair, W R

    1988-01-01

    Fricke chemical dosimetry is used as an indirect measure of the free radical production of ionizing irradiation. We adapted the Fricke ferrous sulfate radiation dosimeter to examine the chemical effects of high energy shock waves. Significant free radical production was documented. The reaction was dose dependent, predictably increased by acoustic impedance, but curvilinear. A thousand shocks at 18 kilovolts induced the same free radical oxidation as 1100 rad cobalt-60 gamma ionizing irradiation, increasing to 2900 rad in the presence of an air-fluid zone of acoustic impedance. The biological effect of these free radicals was compared to that of cobalt-60 ionizing irradiation by measuring the affect on Chinese hamster cells by clonogenic assay. While cobalt-60 irradiation produced a marked decrease in clonogenic survivors, little effect was noted with high energy shock waves. This suggested that the chemical effects produced by shock waves were either absent or attenuated in the cells, or were inherently less toxic than those of ionizing irradiation.

  8. Effect of gamma radiation on the reduction of Salmonella strains, Listeria monocytogenes, and Shiga toxin-producing Escherichia coli and sensory evaluation of minimally processed spinach (Tetragonia expansa).

    Science.gov (United States)

    Rezende, Ana Carolina B; Igarashi, Maria Crystina; Destro, Maria Teresa; Franco, Bernadette D G M; Landgraf, Mariza

    2014-10-01

    This study evaluated the effects of irradiation on the reduction of Shiga toxin-producing Escherichia coli (STEC), Salmonella strains, and Listeria monocytogenes, as well as on the sensory characteristics of minimally processed spinach. Spinach samples were inoculated with a cocktail of three strains each of STEC, Salmonella strains, and L. monocytogenes, separately, and were exposed to gamma radiation doses of 0, 0.2, 0.4, 0.6, 0.8, and 1.0 kGy. Samples that were exposed to 0.0, 1.0, and 1.5 kGy and kept under refrigeration (4°C) for 12 days were submitted to sensory analysis. D10 -values ranged from 0.19 to 0.20 kGy for Salmonella and from 0.20 to 0.21 for L. monocytogenes; for STEC, the value was 0.17 kGy. Spinach showed good acceptability, even after exposure to 1.5 kGy. Because gamma radiation reduced the selected pathogens without causing significant changes in the quality of spinach leaves, it may be a useful method to improve safety in the fresh produce industry.

  9. Alfven shock trains

    International Nuclear Information System (INIS)

    Malkov, M.A.; Kennel, C.F.; Wu, C.C.; Pellat, R.; Shapiro, V.D.

    1991-01-01

    The Cohen--Kulsrud--Burgers equation (CKB) is used to consider the nonlinear evolution of resistive, quasiparallel Alfven waves subject to a long-wavelength, plane-polarized, monochromatic instability. The instability saturates by nonlinear steepening, which proceeds until the periodic waveform develops an interior scale length comparable to the dissipation length; a fast or an intermediate shock then forms. The result is a periodic train of Alfven shocks of one or the other type. For propagation strictly parallel to the magnetic field, there will be two shocks per instability wavelength. Numerical integration of the time-dependent CKB equation shows that an initial, small-amplitude growing wave asymptotes to a stable, periodic stationary wave whose analytic solution specifies how the type of shock embedded in the shock train, and the amplitude and speed of the shock train, depend on the strength and phase of the instability. Waveforms observed upstream of the Earth's bowshock and cometary shocks resemble those calculated here

  10. Kinetic instabilities in plasmas: from electromagnetic fluctuations to collisionless shocks

    International Nuclear Information System (INIS)

    Ruyer, Charles

    2014-01-01

    Collisionless shocks play a major role in powerful astrophysical objects (e.g., gamma-ray bursts, supernova remnants, pulsar winds, etc.), where they are thought to be responsible for non-thermal particle acceleration and radiation. Numerical simulations have shown that, in the absence of an external magnetic field, these self-organizing structures originate from electromagnetic instabilities triggered by high-velocity colliding flows. These Weibel-like instabilities are indeed capable of producing the magnetic turbulence required for both efficient scattering and Fermi-type acceleration. Along with rapid advances in their theoretical understanding, intense effort is now underway to generate collisionless shocks in the laboratory using energetic lasers. In a first part we study the (w,k)-resolved electromagnetic thermal spectrum sustained by a drifting relativistic plasma. In particular, we obtain analytical formulae for the fluctuation spectra, the latter serving as seeds for growing magnetic modes in counterstreaming plasmas. Distinguishing between sub-luminal and supra-luminal thermal fluctuations, we derived analytical formulae of their respective spectral contributions. Comparisons with particle-in-cell (PIC) simulations are made, showing close agreement in the sub-luminal regime along with some discrepancy in the supra-luminal regime. Our formulae are then used to estimate the saturation time of the Weibel instability of relativistic pair plasmas. Our predictions are shown to match 2-D particle-in-cell (PIC) simulations over a three-decade range in flow energy. We then develop a predictive kinetic model of the nonlinear phase of the Weibel instability induced by two counter-streaming, symmetric and non-relativistic ion beams. This self consistent, fully analytical model allows us to follow the evolution of the beams' properties up to a stage close to complete isotropization and thus to shock formation. Its predictions are supported by 2D and 3D particle

  11. Scale-up fermentation of oil palm empty fruit bunch to produce ruminant feed by radiation processing

    International Nuclear Information System (INIS)

    Awang, M.R.; Mutaat, H.H.; Deres, R.M.; Kume, Tamikazu.

    1992-01-01

    Scale-up fermentation and irradiation conditions of empty fruit bunch (EFB) of oil palm were examined to produce a large amount of fermented products for animal feeds. The EFB substrates pasteurized by irradiation were inoculated with Coprinus cinereus. After 1 month incubation, the crude fiber contents decreased to 20 - 38% and crude protein contents increased to 9 - 13% in small scale fermentation using conical flask (6 - 20 g EFB). In the case of fermentation using polypropylene bags with 400 g EFB, crude fiber and protein contents were 32 - 34% and 11 - 14%, respectively. A larger plastic container packed with 1.5 kg EFB fiber of 10cm thickness was used for mushroom cultivation. After harvest of mushroom (yields were about 250 g per container), the quality of residual substrates improved further as reflected by its crude fiber content of only 16 - 20%, crude protein content of 6 - 8%. These results show that a large volume of products are available under the good aeration by increasing the number of plastic bags or containers. For the irradiation of a lot of fermentation substrates, the advantage of 60 Co gamma-ray and electron beam irradiator was also discussed. (author)

  12. Nonequilibrium effects on shock-layer radiometry during earth entry.

    Science.gov (United States)

    Arnold, J. O.; Whiting, E. E.

    1973-01-01

    Radiative enhancement factors for the CN violet and N2(+) first negative band systems caused by nonequilibrium thermochemistry in the shock layer of a blunt-nosed vehicle during earth entry are reported. The results are based on radiometric measurements obtained with the aid of a combustion-driven shock tube. The technique of converting the shock-tube measurements into predictions of the enhancement factors for the blunt-body case is described, showing it to be useful for similar applications of other shock-tube measurements.

  13. Impact of Shock Front Rippling and Self-reformation on the Electron Dynamics at Low-Mach-number Shocks

    Science.gov (United States)

    Yang, Zhongwei; Lu, Quanming; Liu, Ying D.; Wang, Rui

    2018-04-01

    Electron dynamics at low-Mach-number collisionless shocks are investigated by using two-dimensional electromagnetic particle-in-cell simulations with various shock normal angles. We found: (1) The reflected ions and incident electrons at the shock front provide an effective mechanism for the quasi-electrostatic wave generation due to the charge-separation. A fraction of incident electrons can be effectively trapped and accelerated at the leading edge of the shock foot. (2) At quasi-perpendicular shocks, the electron trapping and reflection is nonuniform due to the shock rippling along the shock surface and is more likely to take place at some locations accompanied by intense reflected ion-beams. The electron trapping process has a periodical evolution over time due to the shock front self-reformation, which is controlled by ion dynamics. Thus, this is a cross-scale coupling phenomenon. (3) At quasi-parallel shocks, reflected ions can travel far back upstream. Consequently, quasi-electrostatic waves can be excited in the shock transition and the foreshock region. The electron trajectory analysis shows these waves can trap electrons at the foot region and reflect a fraction of them far back upstream. Simulation runs in this paper indicate that the micro-turbulence at the shock foot can provide a possible scenario for producing the reflected electron beam, which is a basic condition for the type II radio burst emission at low-Mach-number interplanetary shocks driven by Coronal Mass Ejections (CMEs).

  14. System Shock: The Archetype of Operational Shock

    Science.gov (United States)

    2017-05-25

    the battle space. They can also facilitate a much greater understanding of the variables involved in each party’s decision - making process. However...system shock nests within current US Army Unified Land Operations doctrine. In order to test the utility of system shock theory to Gray Zone...23 Neil E. Harrison, “Thinking about the World We Make ” in Chaos Theory in the Social Sciences: Foundations and Applications

  15. Universal hydrodynamic flow in holographic planar shock collisions

    Energy Technology Data Exchange (ETDEWEB)

    Chesler, Paul M. [Department of Physics, Harvard University,Cambridge MA 02138 (United States); Kilbertus, Niki [Institut für Theoretische Physik, Universität Regensburg,D-93040 Regensburg (Germany); Schee, Wilke van der [Center for Theoretical Physics, MIT,Cambridge MA 02139 (United States)

    2015-11-20

    We study the collision of planar shock waves in AdS{sub 5} as a function of shock profile. In the dual field theory the shock waves describe planar sheets of energy whose collision results in the formation of a plasma which behaves hydrodynamically at late times. We find that the post-collision stress tensor near the light cone exhibits transient non-universal behavior which depends on both the shock width and the precise functional form of the shock profile. However, over a large range of shock widths, including those which yield qualitative different behavior near the future light cone, and for different shock profiles, we find universal behavior in the subsequent hydrodynamic evolution. Additionally, we compute the rapidity distribution of produced particles and find it to be well described by a Gaussian.

  16. Physiological Studies on Phytate-Degrading Enzymes Produced by Some Fungi with Special Reference to the Effect of Gamma Radiation

    International Nuclear Information System (INIS)

    Shalaby, Kh.E.M.

    2013-01-01

    rice bran soy bean and wheat bran) using Aspergillus niger was investigated. Maximum phytase production occurred after 4 days incubation in case of corn meal and rice bran while other feeds 5 days incubation gave maximum phytase production. Moisture content required for the maximum production of phytase was 50% for corn meal, cotton seed meal and soy bean and 60% for rice bran and wheat bran at 5 dys old inoculum except for soy bean gave 6 days. 1.0 :10 ml of inoculum amount gave maximum phytase activity in 5 feed stuffs. Glucose concentration up to 6% for the corn meal, rice bran and soy bean meal while in case of 10% in cotton meal and wheat bran. Increasing glucose concentration had an adverse effect. Urea little affects the phytase activity at 2%. Phytase production increase with increasing phosphate concentration from 0.1 to 5 mg / 100 g solid state culture depending on the feed, increasing amount of phosphorus resulted in an inhibition in phytase production. Tween 80 at 0.3 to 0.9 had stimulating effect on phytase production depending on the feed stuff. Using low radiation dose (0.5 kGy) gave highest phytase production. Meanwhile dose above 1.0 kGy rapidly decreased phytase production. Cotton seed meal was fermented using Aspergillus niger1 under optimized culture conditions. Enzyme protein precipitates with ammonium sulphate (95%). SDS PAGE 67 kD. Optimum ph and temperature were 5.0 and 50 degree C for 60 m at shaking speed of 150 rpm. Enzyme lost 43.46% and 75.71% of its original activity in pre-incubation at 50 degree C and 60 degree C for 240 min and 360 min, respectively. Phytase was slightly affected at ph range from 5.0 to 7.0. There is a parallel relationship between enzyme concentration and phytate hydrolysis from 0.1 ml to 1.0 ml after that the increase in enzyme activity was non linear and slightly increase with increasing protein concentration. 1.5 % of phytate concentration was the most favorable for maximal phytate hydrolysis and the highest

  17. Pressurized Thermal Shock, Pts

    International Nuclear Information System (INIS)

    Boyd, C.

    2008-01-01

    Pressurized Thermal Shock (Pts) refers to a condition that challenges the integrity of the reactor pressure vessel. The root cause of this problem is the radiation embrittlement of the reactor vessel. This embrittlement leads to an increase in the reference temperature for nil ductility transition (RTNDT). RTNDT can increase to the point where the reactor vessel material can loose fracture toughness during overcooling events. The analysis of the risk of having a Pts for a specific plant is a multi-disciplinary problem involving probabilistic risk analysis (PRA), thermal-hydraulic analysis, and ultimately a structural and fracture analysis of the vessel wall. The PRA effort involves the postulation of overcooling events and ultimately leads to an integrated risk analysis. The thermal-hydraulic effort involves the difficult task of predicting the system behavior during a postulated overcooling scenario with a special emphasis on predicting the thermal and mechanic loadings on the reactor pressure vessel wall. The structural and fracture analysis of the reactor vessel wall relies on the thermal-hydraulic conditions as boundary conditions. The US experience has indicated that medium and large diameter primary system breaks dominate the risk of Pts along with scenarios that involve a stuck open valve (and associated system cooldown) that recloses resulting in system re-pressurization while the vessel wall is cool.

  18. Sepsis and septic shock

    Science.gov (United States)

    Hotchkiss, Richard S.; Moldawer, Lyle L.; Opal, Steven M.; Reinhart, Konrad; Turnbull, Isaiah R.; Vincent, Jean-Louis

    2017-01-01

    For more than two decades, sepsis was defined as a microbial infection that produces fever (or hypothermia), tachycardia, tachypnoea and blood leukocyte changes. Sepsis is now increasingly being considered a dysregulated systemic inflammatory and immune response to microbial invasion that produces organ injury for which mortality rates are declining to 15–25%. Septic shock remains defined as sepsis with hyperlactataemia and concurrent hypotension requiring vasopressor therapy, with in-hospital mortality rates approaching 30–50%. With earlier recognition and more compliance to best practices, sepsis has become less of an immediate life-threatening disorder and more of a long-term chronic critical illness, often associated with prolonged inflammation, immune suppression, organ injury and lean tissue wasting. Furthermore, patients who survive sepsis have continuing risk of mortality after discharge, as well as long-term cognitive and functional deficits. Earlier recognition and improved implementation of best practices have reduced in-hospital mortality, but results from the use of immunomodulatory agents to date have been disappointing. Similarly, no biomarker can definitely diagnose sepsis or predict its clinical outcome. Because of its complexity, improvements in sepsis outcomes are likely to continue to be slow and incremental. PMID:28117397

  19. Transient shock waves in heliosphere and Sun-Earth relations

    International Nuclear Information System (INIS)

    Voeroes, Z.

    1990-01-01

    The problem of shock waves, caused by solar activity in the Earth's magnetosphere and its magnetic field, is discussed. All types of shock waves have their origin either in solar corona effects or in solar eruptions. Ionospheric and magnetospheric effects, such as X and gamma radiation, particle production, geomagnetic storms and shock waves, caused by solar activity, are dealt with and attempts are made to explain their interdependence. The origin and propagation of coronal shock waves, interplanetary shock waves and geomagnetic field disorders are described and their relations discussed. The understanding of the solar corona and wind phenomena seems to allow prediction of geomagnetic storms. The measurement and analysis of solar activity and its effects could yield useful information about shock waves physics, geomagnetosphere structure and relations between the Earth and the Sun. (J.J.). 7 figs., 1 tab., 37 refs

  20. Overview and recent progress of the Magnetized Shock Experiment (MSX)

    Science.gov (United States)

    Weber, T. E.; Intrator, T. P.; Smith, R. J.; Hutchinson, T. M.; Boguski, J. C.; Sears, J. A.; Swan, H. O.; Gao, K. W.; Chapdelaine, L. J.; Winske, D.; Dunn, J. P.

    2013-10-01

    The Magnetized Shock Experiment (MSX) has been constructed to study the physics of super-Alfvènic, supercritical, magnetized shocks. Exhibiting transitional length and time scales much smaller than can be produced through collisional processes, these shocks are observed to create non-thermal distributions, amplify magnetic fields, and accelerate particles to relativistic velocities. Shocks are produced through the acceleration and subsequent stagnation of Field Reversed Configuration (FRC) plasmoids against a high-flux magnetic mirror with a conducting boundary or a plasma target with embedded field. Adjustable shock velocity, density, and magnetic geometry (B parallel, perpendicular, or oblique to k) provide unique access to a wide range of dimensionless parameters relevant to astrophysical shocks. Information regarding the experimental configuration, diagnostics suite, recent simulations, experimental results, and physics goals will be presented. This work is supported by DOE OFES and NNSA under LANS contract DE-AC52-06NA25369 Approved for Public Release: LA-UR-13-24859.

  1. Temporal structure of an electric signal produced upon interaction of radiation from a HF laser with the bottom surface of a water column

    International Nuclear Information System (INIS)

    Andreev, Sergei N; Kazantsev, S Yu; Kononov, I G; Pashinin, Pavel P; Firsov, K N

    2009-01-01

    Generation of an electric signal is investigated when a HF-laser pulse interacts with the lower surface of a water column in a cell with a bottom transparent to laser radiation, while the upper surface of the water column remains open. The electric signal exhibits a temporal structure of two spikes spaced by time τ which is linearly dependent on the laser output energy. It is found that the value of τ (up to 1.3 ms) is an order of magnitude greater than the time during which the vapour pressure in a cavity produced due to the volume explosive boiling of water in the exposed area is greater than the atmospheric pressure. The second spike was determined to appear upon the collapse of the vapour cavity. A mathematical model is constructed that explains the motion of the water column above the vapour cavity taking into account the temporal evolution of the vapour pressure above it. It is shown that the prolonged lifetime of the vapour cavity after the decrease in the vapour pressure down to the atmospheric value is caused by the inertial motion of the water column acquiring the velocity at the initial stage of the cavity expansion. The calculated time of the water column motion agrees well with the experimental time interval between the spikes of an electric signal. (interaction of laser radiation with matter)

  2. Estimation of the radiation strength and dose equivalent from activities produced by p+ sup 2 sup 3 sup 8 U fission reaction

    CERN Document Server

    Kawakami, H

    2002-01-01

    The decay curves of radiation and dose equivalent of mass from 72 to 171 produced by p+ sup 2 sup 3 sup 8 U fission reaction are calculated under the consideration that 1) dose equivalent by decay of each nuclide is estimated by each calculation and 2) only one isomer is considered when there are some isomers in the chain decay. Four isotopes selected to calculate the time-depend intensity in the chain decay. Total radiation is 150 times, which is difference of proton beam current, larger than the value not considered isomer. There is no problem in the following isobar, which decays after beam off, 75, 78, 79, 81, 89, 100, 101, 104, 107, 116, 138, 163, 164 and 168. The nuclides such as 81, 95, 98, 102, 108, 146, 152, 158, 165, 169 and 170 are long life, but have low or weak energy of gamma-ray. Nuclides of gas or high vapor pressure show different values from the calculation results, because total nuclide did not accumulate. This analysis showed the isomer ratio was not identified by experiments. The value is...

  3. Shock-induced modification of inorganic powders

    International Nuclear Information System (INIS)

    Graham, R.A.; Morosin, B.; Venturini, E.L.; Beauchamp, E.K.; Hammetter, W.F.

    1984-01-01

    The results of studies performed to quantify the characteristics of TiO2, ZrO2 and Si3N4 powders exposed to explosive loading and post-shock analysis are reported. The shocks were produced with plane wave generators and explosive pads impinging on steel disks, a copper recovery fixture, and then the samples. Peak pressures of 13 and 17 GPa were attained, along with 40 GPz at the center of the powder cavity. Data are provided on the changes occurring during the explosive densification and X-ray and paramagnetic studies of the products. Only fractured disks were obtained in the trials. The shock-treated materials were more free flowing than the original powders, which were fluffy. Post-shock annealing was a significant feature of the treated powders

  4. SELF-REGULATED SHOCKS IN MASSIVE STAR BINARY SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Parkin, E. R.; Sim, S. A., E-mail: parkin@mso.anu.edu.au, E-mail: s.sim@qub.ac.uk [Research School of Astronomy and Astrophysics, Australian National University, ACT 2611 (Australia)

    2013-04-20

    In an early-type, massive star binary system, X-ray bright shocks result from the powerful collision of stellar winds driven by radiation pressure on spectral line transitions. We examine the influence of the X-rays from the wind-wind collision shocks on the radiative driving of the stellar winds using steady-state models that include a parameterized line force with X-ray ionization dependence. Our primary result is that X-ray radiation from the shocks inhibits wind acceleration and can lead to a lower pre-shock velocity, and a correspondingly lower shocked plasma temperature, yet the intrinsic X-ray luminosity of the shocks, L{sub X}, remains largely unaltered, with the exception of a modest increase at small binary separations. Due to the feedback loop between the ionizing X-rays from the shocks and the wind driving, we term this scenario as self-regulated shocks. This effect is found to greatly increase the range of binary separations at which a wind-photosphere collision is likely to occur in systems where the momenta of the two winds are significantly different. Furthermore, the excessive levels of X-ray ionization close to the shocks completely suppress the line force, and we suggest that this may render radiative braking less effective. Comparisons of model results against observations reveal reasonable agreement in terms of log (L{sub X}/L{sub bol}). The inclusion of self-regulated shocks improves the match for kT values in roughly equal wind momenta systems, but there is a systematic offset for systems with unequal wind momenta (if considered to be a wind-photosphere collision).

  5. SELF-REGULATED SHOCKS IN MASSIVE STAR BINARY SYSTEMS

    International Nuclear Information System (INIS)

    Parkin, E. R.; Sim, S. A.

    2013-01-01

    In an early-type, massive star binary system, X-ray bright shocks result from the powerful collision of stellar winds driven by radiation pressure on spectral line transitions. We examine the influence of the X-rays from the wind-wind collision shocks on the radiative driving of the stellar winds using steady-state models that include a parameterized line force with X-ray ionization dependence. Our primary result is that X-ray radiation from the shocks inhibits wind acceleration and can lead to a lower pre-shock velocity, and a correspondingly lower shocked plasma temperature, yet the intrinsic X-ray luminosity of the shocks, L X , remains largely unaltered, with the exception of a modest increase at small binary separations. Due to the feedback loop between the ionizing X-rays from the shocks and the wind driving, we term this scenario as self-regulated shocks. This effect is found to greatly increase the range of binary separations at which a wind-photosphere collision is likely to occur in systems where the momenta of the two winds are significantly different. Furthermore, the excessive levels of X-ray ionization close to the shocks completely suppress the line force, and we suggest that this may render radiative braking less effective. Comparisons of model results against observations reveal reasonable agreement in terms of log (L X /L bol ). The inclusion of self-regulated shocks improves the match for kT values in roughly equal wind momenta systems, but there is a systematic offset for systems with unequal wind momenta (if considered to be a wind-photosphere collision).

  6. A Reverse Shock in GRB 160509A

    Science.gov (United States)

    Laskar, Tanmoy; Alexander, Kate D.; Berger, Edo; Fong, Wen-fai; Margutti, Raffaella; Shivvers, Isaac; Williams, Peter K. G.; Kopač, Drejc; Kobayashi, Shiho; Mundell, Carole; Gomboc, Andreja; Zheng, WeiKang; Menten, Karl M.; Graham, Melissa L.; Filippenko, Alexei V.

    2016-12-01

    We present the second multi-frequency radio detection of a reverse shock in a γ-ray burst. By combining our extensive radio observations of the Fermi-Large Area Telescope γ-ray burst 160509A at z = 1.17 up to 20 days after the burst with Swift X-ray observations and ground-based optical and near-infrared data, we show that the afterglow emission comprises distinct reverse shock and forward shock contributions: the reverse shock emission dominates in the radio band at ≲10 days, while the forward shock emission dominates in the X-ray, optical, and near-infrared bands. Through multi-wavelength modeling, we determine a circumburst density of {n}0≈ {10}-3 {{cm}}-3, supporting our previous suggestion that a low-density circumburst environment is conducive to the production of long-lasting reverse shock radiation in the radio band. We infer the presence of a large excess X-ray absorption column, N H ≈ 1.5 × 1022 {{cm}}-2, and a high rest-frame optical extinction, A V ≈ 3.4 mag. We identify a jet break in the X-ray light curve at {t}{jet}≈ 6 {days}, and thus derive a jet opening angle of {θ }{jet}≈ 4^\\circ , yielding a beaming-corrected kinetic energy and radiated γ-ray energy of {E}{{K}}≈ 4× {10}50 erg and {E}γ ≈ 1.3× {10}51 erg (1-104 keV, rest frame), respectively. Consistency arguments connecting the forward shocks and reverse shocks suggest a deceleration time of {t}{dec} ≈ 460 s ≈ T 90, a Lorentz factor of {{Γ }}({t}{dec})≈ 330, and a reverse-shock-to-forward-shock fractional magnetic energy density ratio of {R}{{B}}\\equiv {ɛ }{{B},{RS}}/{ɛ }{{B},{FS}}≈ 8. Our study highlights the power of rapid-response radio observations in the study of the properties and dynamics of γ-ray burst ejecta.

  7. Spherical strong-shock generation for shock-ignition inertial fusion

    Energy Technology Data Exchange (ETDEWEB)

    Theobald, W.; Seka, W.; Lafon, M.; Anderson, K. S.; Hohenberger, M.; Marshall, F. J.; Michel, D. T.; Solodov, A. A.; Stoeckl, C.; Edgell, D. H.; Yaakobi, B.; Shvydky, A. [Laboratory for Laser Energetics and Fusion Science Center, University of Rochester, Rochester, New York 14623 (United States); Nora, R.; Betti, R. [Laboratory for Laser Energetics and Fusion Science Center, University of Rochester, Rochester, New York 14623 (United States); Department of Mechanical Engineering and Department of Physics, University of Rochester, Rochester, New York 14623 (United States); Casner, A.; Reverdin, C. [CEA, DAM, DIF, F-91297 Arpajon (France); Ribeyre, X.; Vallet, A. [Université de Bordeaux-CNRS-CEA, CELIA (Centre Lasers Intenses et Applications) UMR 5107 F-33400 Talence (France); Peebles, J.; Beg, F. N. [University of California, San Diego, La Jolla, California 92093 (United States); and others

    2015-05-15

    Recent experiments on the Laboratory for Laser Energetics' OMEGA laser have been carried out to produce strong shocks in solid spherical targets with direct laser illumination. The shocks are launched at pressures of several hundred Mbars and reach Gbar upon convergence. The results are relevant to the validation of the shock-ignition scheme and to the development of an OMEGA experimental platform to study material properties at Gbar pressures. The experiments investigate the strength of the ablation pressure and the hot-electron production at incident laser intensities of ∼2 to 6 × 10{sup 15 }W/cm{sup 2} and demonstrate ablation pressures exceeding 300 Mbar, which is crucial to developing a shock-ignition target design for the National Ignition Facility. The timing of the x-ray flash from shock convergence in the center of the solid plastic target is used to infer the ablation and shock pressures. Laser–plasma instabilities produce hot-electrons with a moderate temperature (<100 keV). The instantaneous conversion efficiencies of laser power into hot-electron power reached up to ∼15% in the intensity spike. The large amount of hot electrons is correlated with an earlier x-ray flash and a strong increase in its magnitude. This suggests that hot electrons contribute to the augmentation of the shock strength.

  8. Interplanetary fast shock diagnosis with the radio receiver on Ulysses

    Science.gov (United States)

    Hoang, S.; Pantellini, F.; Harvey, C. C.; Lacombe, C.; Mangeney, A.; Meuer-Vernet, N.; Perche, C.; Steinberg, J.-L.; Lengyel-Frey, D.; Macdowall, R. J.

    1992-01-01

    The radio receiver on Ulysses records the quasi-thermal noise which allows a determination of the density and temperature of the cold (core) electrons of the solar wind. Seven interplanetary fast forward or reverse shocks are identified from the density and temperature profiles, together with the magnetic field profile from the Magnetometer experiment. Upstream of the three strongest shocks, bursts of nonthermal waves are observed at the electron plasma frequency f(peu). The more perpendicular the shock, the longer the time interval during which these upstream bursts are observed. For one of the strongest shocks we also observe two kinds of upstream electromagnetic radiation: radiation at 2 f(peu), and radiation at the downstream electron plasma frequency, which propagates into the less dense upstream regions.

  9. High energy emission of supernova sn 1987a. Cosmic rays acceleration in mixed shocks

    International Nuclear Information System (INIS)

    Lehoucq, Roland

    1992-01-01

    In its first part, this research thesis reports the study of the high energy emission of the sn 1987 supernova, based on a Monte Carlo simulation of the transfer of γ photons emitted during disintegration of radioactive elements (such as "5"6Ni, "5"6Co, "5"7Co and "4"4Ti) produced during the explosion. One of the studied problems is the late evolution (beyond 1200 days) of light curvature which is very different when it is powered by the radiation of a central object or by radioactivity. The second part reports the study of acceleration of cosmic rays in two-fluid shock waves in order to understand the different asymmetries noticed in hot spots of extragalactic radio-sources. This work comprises the resolution of structure equations of a shock made of a conventional fluid and a relativistic one, in presence or absence of a magnetic field [fr

  10. Measurement of the development and evolution of shock waves in a laser-induced gas breakdown plasma

    International Nuclear Information System (INIS)

    Chu, T.K.; Johnson, L.C.

    1975-01-01

    Space- and time-resolved interferometric measurements of electron density in CO 2 -laser produced plasmas in helium or hydrogen are made near the laser focal spot. Immediately after breakdown, a rapidly growing region of approximately uniform plasma density appears at the focal spot. After a few tens of nanoseconds, shock waves are formed, propagating both transverse and parallel to the incident laser beam direction. Behind the transverse propagating shock is an on-axis density minimum, which results in laser-beam self-trapping. The shock wave propagating toward the focusing lens effectively shields the interior plasma from the incident beam because the lower plasma temperature and higher plasma density in the shock allow strong absorption of the incident beam energy. By arranging the laser radiation-plasma interaction to begin at a plasma-vacuum interface at the exit of a free-expansion jet, this backward propagating shock wave is eliminated, thus permitting efficient energy deposition in the plasma interior

  11. High-energy radiation from collisions of high-velocity clouds and the Galactic disc

    Science.gov (United States)

    del Valle, Maria V.; Müller, A. L.; Romero, G. E.

    2018-04-01

    High-velocity clouds (HVCs) are interstellar clouds of atomic hydrogen that do not follow normal Galactic rotation and have velocities of a several hundred kilometres per second. A considerable number of these clouds are falling down towards the Galactic disc. HVCs form large and massive complexes, so if they collide with the disc a great amount of energy would be released into the interstellar medium. The cloud-disc interaction produces two shocks: one propagates through the cloud and the other through the disc. The properties of these shocks depend mainly on the cloud velocity and the disc-cloud density ratio. In this work, we study the conditions necessary for these shocks to accelerate particles by diffusive shock acceleration and we study the non-thermal radiation that is produced. We analyse particle acceleration in both the cloud and disc shocks. Solving a time-dependent two-dimensional transport equation for both relativistic electrons and protons, we obtain particle distributions and non-thermal spectral energy distributions. In a shocked cloud, significant synchrotron radio emission is produced along with soft gamma rays. In the case of acceleration in the shocked disc, the non-thermal radiation is stronger; the gamma rays, of leptonic origin, might be detectable with current instruments. A large number of protons are injected into the Galactic interstellar medium, and locally exceed the cosmic ray background. We conclude that under adequate conditions the contribution from HVC-disc collisions to the galactic population of relativistic particles and the associated extended non-thermal radiation might be important.

  12. Hydraulic shock absorbers

    International Nuclear Information System (INIS)

    Thatcher, G.; Davidson, D. F.

    1984-01-01

    A hydraulic shock absorber of the dash pot kind for use with electrically conducting liquid such as sodium, has magnet means for electro magnetically braking a stream of liquid discharged from the cylinder. The shock absorber finds use in a liquid metal cooled nuclear reactor for arresting control rods

  13. Climate shocks and conflict

    NARCIS (Netherlands)

    Papaioannou, Kostadis J.

    2016-01-01

    This paper offers a historical micro-level analysis of the impact of climate shocks on the incidence of civil conflict in colonial Nigeria (1912-1945). Primary historical sources on court cases, prisoners and homicides are used to capture conflict. To measure climate shocks we use the deviation

  14. Change of the NADPH depending superoxide producing and ferri hemoglobin reducing activities of cytochrome b558 from spleen cells and erythrocytes membranes induced by the radiation of different character

    International Nuclear Information System (INIS)

    Melkonyan, L.G.; Simonyan, R.M.; Simonyan, M.A.; Sekoyan, E.S.

    2009-01-01

    After the X radiation, UVA radiation and ultrasound radiation of new isoforms of cytochrome cyt b 5 58 from rats erythrocyte membranes - EM (cyt b 5 58III) and from spleen cell membranes (SCM) in vitro, as well as after the radiation of EM ex vivo, the suppression of both NADPH depending O 2 - producing and ferrihemoglobin (ferriHb)-reducing activities of cyt b 5 58 from EM and SCM in homogeneous (in solution) and heterogeneous phases (in EM and SCM) at various scopes takes place. These changes are associated with the destabilization of EM and SCM, conditioned by the change of the aggregation degree of these hemoproteins in EM and SCM, hemoproteins as a result of the influence of the hydrogen peroxide formed during radiolysis and photolysis of the water medium. After He-Ne laser radiation of the cyt b 5 58 from EM and SCM in vitro an increase of the NADPH depending O 2 - producing and ferriHb-reducing activities of the cyt b 5 58 from EM and SCM in homogenous and heterogeneous phases (in membranes) takes place. It is supposed that the suppression (by X-, UVA- and US-radiation) and the stimulation (by He-Ne laser radiation) of the immune system activity and the oxygen homeostasis are associated with the corresponding decrease and increase of the NADPH depending O 2 - producing and ferriHb-reducings activity of the new isoforms of cyt b 5 58 from EM and SCM in homogeneous and heterogeneous phases

  15. Radiation degradation of biological waste (aflatoxins) produced in food laboratory; Degradacao por radiacao de residuos biologicos (aflatoxinas) produzidos em laboratorio de alimentos

    Energy Technology Data Exchange (ETDEWEB)

    Rogovschi, Vladimir Dias

    2009-07-01

    Many filamentous fungi can produce secondary metabolites, called mycotoxins, which can be found in food and agricultural products. One of the main genera of myco toxigenic fungi related to the food chain is the Aspergillus spp. There are over 400 mycotoxins described in the literature, the most common the aflatoxins B1, B2, G1 and G2. The mycotoxins are commonly found in foods and are considered one of the most dangerous contaminants. The aflatoxin B1 is classified in group one by the International Agency of Research on Cancer. Aflatoxins resisting for more than one hour in autoclave making it necessary to other means of degradation of these toxins. This work aimed to observe the effects of gamma radiation of {sup 60}Co and electron beams in the degradation of aflatoxins and compare the damage caused on the morphology of the Aspergillus flavus. The fungus was grown on potato dextrose agar (PDA) for 10 days and was subsequently transferred to coconut agar medium, and maintained for 14 days at 25 degree C. After this step the coconut agar was ground to become a homogeneous pasty and was irradiated with doses of 2.5, 5.0, 10 and 20 kGy. The samples used in scanning electron microscopy were irradiated with doses of 0, 2.5, 5.0, 10 and 20 kGy with sources of {sup 60}Co and electron beams. Irradiation with electron accelerator showed a slightly higher degradation to gamma radiation, reducing 29.93 %, 34.50 %, 52.63 % and 72.30 % for doses of 2.5, 5.0, 10 and 20 kGy, respectively. The Scanning Electron Microscopy showed that doses of 2.5 to 10 kGy did not cause damage to the fungus, but with a dose of 20 kGy it can be observed fungal damage to structures. (author)

  16. Martian Bow Shock and Magnetic Pile-Up Barrier Formation Due to the Exosphere Ion Mass-Loading

    Directory of Open Access Journals (Sweden)

    Eojin Kim

    2011-03-01

    Full Text Available Bow shock, formed by the interaction between the solar wind and a planet, is generated in different patterns depending on the conditions of the planet. In the case of the earth, its own strong magnetic field plays a critical role in determining the position of the bow shock. However, in the case of Mars of which has very a small intrinsic magnetic field, the bow shock is formed by the direct interaction between the solar wind and the Martian ionosphere. It is known that the position of the Martian bow shock is affected by the mass loading-effect by which the supersonic solar wind velocity becomes subsonic as the heavy ions originating from the planet are loaded on the solar wind. We simulated the Martian magnetosphere depending on the changes of the density and velocity of the solar wind by using the three-dimensional magnetohydrodynamic model built by modifying the comet code that includes the mass loading effect. The Martian exosphere model of was employed as the Martian atmosphere model, and only the photoionization by the solar radiation was considered in the ionization process of the neutral atmosphere. In the simulation result under the normal solar wind conditions, the Martian bow shock position in the subsolar point direction was consistent with the result of the previous studies. The three-dimensional simulation results produced by varying the solar wind density and velocity were all included in the range of the Martian bow shock position observed by Mariner 4, Mars 2, 3, 5, and Phobos 2. Additionally, the simulation result also showed that the change of the solar wind density had a greater effect on the Martian bow shock position than the change of the solar wind velocity. Our result may be useful in analyzing the future observation data by Martian probes.

  17. Search Coil vs. Fluxgate Magnetometer Measurements at Interplanetary Shocks

    Science.gov (United States)

    Wilson, L.B., III

    2012-01-01

    We present magnetic field observations at interplanetary shocks comparing two different sample rates showing significantly different results. Fluxgate magnetometer measurements show relatively laminar supercritical shock transitions at roughly 11 samples/s. Search coil magnetometer measurements at 1875 samples/s, however, show large amplitude (dB/B as large as 2) fluctuations that are not resolved by the fluxgate magnetometer. We show that these fluctuations, identified as whistler mode waves, would produce a significant perturbation to the shock transition region changing the interpretation from laminar to turbulent. Thus, previous observations of supercritical interplanetary shocks classified as laminar may have been under sampled.

  18. PENETRATION OF A SHOCK WAVE IN A FLAME FRONT

    Directory of Open Access Journals (Sweden)

    Dan PANTAZOPOL

    2009-09-01

    Full Text Available The present paper deals with the interactions between a fully supersonic flame front, situated in a supersonic two-dimensional flow of an ideal homogeneous combustible gas mixture, and an incident shock wawe, which is penetrating in the space of the hot burnt gases. A possible configuration, which was named ,,simple penetration” is examined. For the anlysis of the interference phenomena, shock polar and shock-combustion polar are used. At the same time, the paper shows the possibility to produce similar but more complicated configurations, which may contain expansion fans and reflected shock waves.

  19. Particle acceleration at shocks in the inner heliosphere

    Science.gov (United States)

    Parker, Linda Neergaard

    This dissertation describes a study of particle acceleration at shocks via the diffusive shock acceleration mechanism. Results for particle acceleration at both quasi-parallel and quasi-perpendicular shocks are presented to address the question of whether there are sufficient particles in the solar wind thermal core, modeled as either a Maxwellian or kappa- distribution, to account for the observed accelerated spectrum. Results of accelerating the theoretical upstream distribution are compared to energetic observations at 1 AU. It is shown that the particle distribution in the solar wind thermal core is sufficient to explain the accelerated particle spectrum downstream of the shock, although the shape of the downstream distribution in some cases does not follow completely the theory of diffusive shock acceleration, indicating possible additional processes at work in the shock for these cases. Results show good to excellent agreement between the theoretical and observed spectral index for one third to one half of both quasi-parallel and quasi-perpendicular shocks studied herein. Coronal mass ejections occurring during periods of high solar activity surrounding solar maximum can produce shocks in excess of 3-8 shocks per day. During solar minimum, diffusive shock acceleration at shocks can generally be understood on the basis of single independent shocks and no other shock necessarily influences the diffusive shock acceleration mechanism. In this sense, diffusive shock acceleration during solar minimum may be regarded as Markovian. By contrast, diffusive shock acceleration of particles at periods of high solar activity (e.g. solar maximum) see frequent, closely spaced shocks that include the effects of particle acceleration at preceding and following shocks. Therefore, diffusive shock acceleration of particles at solar maximum cannot be modeled on the basis of diffusive shock acceleration as a single, independent shock and the process is essentially non-Markovian. A

  20. Pediatric Toxic Shock Syndrome

    Directory of Open Access Journals (Sweden)

    Jennifer Yee

    2017-09-01

    Full Text Available Audience: This scenario was developed to educate emergency medicine residents on the diagnosis and management of a pediatric patient with toxic shock syndrome. The case is also appropriate for teaching of medical students and advanced practice providers, as well as a review of the principles of crisis resource management, teamwork, and communication. Introduction: Toxic shock syndrome is a low-frequency, high-acuity scenario requiring timely identification and aggressive management. If patients suffering from this condition are managed incorrectly, they may progress into multi-organ dysfunction and potentially death. Toxic shock syndrome has been associated with Streptococcus and Staphylococcus aureus (Staph. Approximately half of Staph cases are associated with menstruation, which was first described in the 1970s-1980s and was associated with the use of absorbent tampons.1 Group A Streptococcus may cause complications such as necrotizing fasciitis and gangrenous myositis.2 Pediatric patients may present critically ill from toxic shock syndrome. Providers need to perform a thorough history and physical exam to discern the source of infection. Management requires aggressive care with antibiotics and IV fluids. Objectives: By the end of this simulation session, the learner will be able to: 1 Recognize toxic shock syndrome. 2 Review the importance of a thorough physical exam. 3 Discuss management of toxic shock syndrome, including supportive care and the difference in antibiotic choices for streptococcal and staphylococcal toxic shock syndrome. 4 Appropriately disposition a patient suffering from toxic shock syndrome. 5 Communicate effectively with team members and nursing staff during a resuscitation of a critically ill patient. Method: This session was conducted using high-fidelity simulation, followed by a debriefing session and lecture on toxic shock syndrome.

  1. High pressure generation by laser driven shock waves: application to equation of state measurement; Generation de hautes pressions par choc laser: application a la mesure d'equations d'etat

    Energy Technology Data Exchange (ETDEWEB)

    Benuzzi, A

    1997-12-15

    This work is dedicated to shock waves and their applications to the study of the equation of state of compressed matter.This document is divided into 6 chapters: 1) laser-produced plasmas and abrasion processes, 2) shock waves and the equation of state, 3) relative measuring of the equation of state, 4) comparison between direct and indirect drive to compress the target, 5) the measurement of a new parameter: the shock temperature, and 6) control and measurement of the pre-heating phase. In this work we have reached relevant results, we have shown for the first time the possibility of generating shock waves of very high quality in terms of spatial distribution, time dependence and of negligible pre-heating phase with direct laser radiation. We have shown that the shock pressure stays unchanged as time passes for targets whose thickness is over 10 {mu}m. A relative measurement of the equation of state has been performed through the simultaneous measurement of the velocity of shock waves passing through 2 different media. The great efficiency of the direct drive has allowed us to produce pressures up to 40 Mbar. An absolute measurement of the equation of state requires the measurement of 2 parameters, we have then performed the measurement of the colour temperature of an aluminium target submitted to laser shocks. A simple model has been developed to infer the shock temperature from the colour temperature. The last important result is the assessment of the temperature of the pre-heating phase that is necessary to know the media in which the shock wave propagates. The comparison of the measured values of the reflectivity of the back side of the target with the computed values given by an adequate simulation has allowed us to deduce the evolution of the temperature of the pre-heating phase. (A.C.)

  2. Shocks near Jamming

    Science.gov (United States)

    Gómez, Leopoldo R.; Turner, Ari M.; van Hecke, Martin; Vitelli, Vincenzo

    2012-02-01

    Nonlinear sound is an extreme phenomenon typically observed in solids after violent explosions. But granular media are different. Right when they jam, these fragile and disordered solids exhibit a vanishing rigidity and sound speed, so that even tiny mechanical perturbations form supersonic shocks. Here, we perform simulations in which two-dimensional jammed granular packings are dynamically compressed and demonstrate that the elementary excitations are strongly nonlinear shocks, rather than ordinary phonons. We capture the full dependence of the shock speed on pressure and impact intensity by a surprisingly simple analytical model.

  3. Mechanical shock absorber

    International Nuclear Information System (INIS)

    Vrillon, Bernard.

    1973-01-01

    The mechanical shock absorber described is made of a constant thickness plate pierced with circular holes regularly distributed in such a manner that for all the directions along which the strain is applied during the shock, the same section of the substance forming the plate is achieved. The shock absorber is made in a metal standing up to extensive deformation before breaking, selected from a group comprising mild steels and austenitic stainless steels. This apparatus is used for handling pots of fast neutron reactor fuel elements [fr

  4. Shock formation of HCO+

    International Nuclear Information System (INIS)

    Elitzur, M.

    1983-01-01

    It is shown that shocks propagating in dense molecular regions will lead to a decrease in HCO + relative abundance, in agreement with previous results by Iglesias and Silk. The shock enhancement of HCO + detected in the supernova remnant IC 443 by Dickenson et al. is due to enhanced ionization in the shocked material. This is the result of the material penetrating the remnant cavity where it becomes exposed to the trapped cosmic rays. A similar enhancement appears to have been detected by Wootten in W28 and is explained by the same model

  5. Climate Change Effects on Agriculture: Economic Responses to Biophysical Shocks

    Science.gov (United States)

    Nelson, Gerald C.; Valin, Hugo; Sands, Ronald D.; Havlik, Petr; Ahammad, Helal; Deryng, Delphine; Elliott, Joshua; Fujimori, Shinichiro; Hasegawa, Tomoko; Heyhoe, Edwina

    2014-01-01

    Agricultural production is sensitive to weather and thus directly affected by climate change. Plausible estimates of these climate change impacts require combined use of climate, crop, and economic models. Results from previous studies vary substantially due to differences in models, scenarios, and data. This paper is part of a collective effort to systematically integrate these three types of models. We focus on the economic component of the assessment, investigating how nine global economic models of agriculture represent endogenous responses to seven standardized climate change scenarios produced by two climate and five crop models. These responses include adjustments in yields, area, consumption, and international trade. We apply biophysical shocks derived from the Intergovernmental Panel on Climate Change's representative concentration pathway with end-of-century radiative forcing of 8.5 W/m(sup 2). The mean biophysical yield effect with no incremental CO2 fertilization is a 17% reduction globally by 2050 relative to a scenario with unchanging climate. Endogenous economic responses reduce yield loss to 11%, increase area of major crops by 11%, and reduce consumption by 3%. Agricultural production, cropland area, trade, and prices show the greatest degree of variability in response to climate change, and consumption the lowest. The sources of these differences include model structure and specification; in particular, model assumptions about ease of land use conversion, intensification, and trade. This study identifies where models disagree on the relative responses to climate shocks and highlights research activities needed to improve the representation of agricultural adaptation responses to climate change.

  6. Relativistic shocks in electron-positron plasmas, and polar cap accretion onto neutron stars: Two non-linear problems in astrophysical plasma physics

    Energy Technology Data Exchange (ETDEWEB)

    Arons, J.

    1988-08-15

    I outline particle simulations and theory of relativistic shock waves in an e/sup +-/ plasma. Magnetic reflection of particles is an essential role in the shock structure. Instability of the reflected particles in the shock front produces intense extraordinary mode radiation. Such shocks are candidates for the particle accelerator in plerions and in extragalactic jets only if the upstream Poynting flux composes no more than 10% of the total. I summarize analytical and numerical studies of radiation dominated accretion onto the magnetic poles of neutron stars. The upper limit to the photon luminosity depends upon magnetic confinement, not upon the dragging of photons into the star. Numerical solutions show the plasma forms large scale ''photon bubbles.'' I suggest the percolative loss of radiation controls the pressure and therefore the limits of magnetic confinement. Loss of magnetic confinement through resistive interchange instability is suggested as a means of generating TeV to PeV voltage drops along the magnetic field. 34 refs., 6 figs., 1 tab.

  7. Relativistic shocks in electron-positron plasmas, and polar cap accretion onto neutron stars: Two non-linear problems in astrophysical plasma physics

    International Nuclear Information System (INIS)

    Arons, J.

    1988-01-01

    I outline particle simulations and theory of relativistic shock waves in an e/sup +-/ plasma. Magnetic reflection of particles is an essential role in the shock structure. Instability of the reflected particles in the shock front produces intense extraordinary mode radiation. Such shocks are candidates for the particle accelerator in plerions and in extragalactic jets only if the upstream Poynting flux composes no more than 10% of the total. I summarize analytical and numerical studies of radiation dominated accretion onto the magnetic poles of neutron stars. The upper limit to the photon luminosity depends upon magnetic confinement, not upon the dragging of photons into the star. Numerical solutions show the plasma forms large scale ''photon bubbles.'' I suggest the percolative loss of radiation controls the pressure and therefore the limits of magnetic confinement. Loss of magnetic confinement through resistive interchange instability is suggested as a means of generating TeV to PeV voltage drops along the magnetic field. 34 refs., 6 figs., 1 tab

  8. An autopsied case of human chorionic gonadotropin (HCG)-producing lung cancer accompanied by bilateral radiation pneumonitis due to small doses of irradiation

    International Nuclear Information System (INIS)

    Tano, Yoshihiko; Adachi, Michifumi; Kimura, Makoto; Matsushima, Toshiharu; Torii, Takashi

    1990-01-01

    An autopsied case of human chorionic gonadotropin (HCG)-producing lung cancer accompanied by bilateral radiation pneumonitis is reported. A 68 year-old male was admitted to our hospital because of an abnormal shadow in his chest x-ray. Lung cancer was diagnosed and treated with radiotherapy. The radiotherapy (1,200 cGy) was discontinued, however because his general condition deteriorated. Chest x-rays then showed a pneumonia-like shadow in the projected field of irradiation. The same shadow was observed in the contralateral lung field one month later. Gynecomastia and an elevated level of serum HCG were noticed during hospitalization. The patient died and an autopsy was performed. Histopathological examination upon autopsy confirmed a large cell carcinoma of the lung which stained positively for HCG with an immunoenzyme labelling technique using the PAP method. Marked fibrosis and thickening of the alveolar septae were histologically demonstrated in the projected field of irradiation and the contralateral field where chest x-rays showed the pneumonia-like shadow. (author)

  9. Anti-inflammatory effects of chloroform soluble fraction from Perilla frutescens britton leaves produced by radiation breeding in RAW264.7 cells

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Yun Ho; So, Yang Kang; Kim, Jin Baek; Jin, Chang Hyun [Advance Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Lee, Jun Soo [Dept. Food Science and Technology Graduate School, Chungbuk National University, Cheongju (Korea, Republic of); Lee, Seung Young [Freshwater Bioresources Utilization Division, Nakdonggang National Institute of Biological Resources, Sangju (Korea, Republic of)

    2016-11-15

    The present study aimed to determine the anti-inflammatory effects of each solvent fraction of a mutant Perilla frutescens produced by radiation breeding. Following extraction with 80% methanol, P. frutescens was fractionated in the order of hexane, chloroform, ethyl acetate, and butanol; the chloroform fraction exhibited less cytotoxicity, the greatest inhibitory effect on the production of nitric oxide (NO), and the highest rate of inhibition on the generation of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and interferon-β (IFN-β). The chloroform fraction also suppressed the mRNA and protein levels of inducible nitric oxide synthase (iNOS) and reduced the activation of nuclear factor-{sub κ}B (NF-{sub κ}B) in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Finally, the presence of corosolic acid in the chloroform fraction was identifed. Taken together, the present fndings indicate that the chloroform fraction obtained from mutant P. frutescens inhibited NO production in LPSstimulated RAW264.7 cells via the suppression of iNOS expression and the inactivation of NF-{sub κ}B.

  10. An autopsied case of human chorionic gonadotropin (HCG)-producing lung cancer accompanied by bilateral radiation pneumonitis due to small doses of irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Tano, Yoshihiko; Adachi, Michifumi; Kimura, Makoto; Matsushima, Toshiharu; Torii, Takashi (Kawasaki Medical School, Kawasaki Hospital, Okayama (Japan))

    1990-07-01

    An autopsied case of human chorionic gonadotropin (HCG)-producing lung cancer accompanied by bilateral radiation pneumonitis is reported. A 68 year-old male was admitted to our hospital because of an abnormal shadow in his chest x-ray. Lung cancer was diagnosed and treated with radiotherapy. The radiotherapy (1,200 cGy) was discontinued, however because his general condition deteriorated. Chest x-rays then showed a pneumonia-like shadow in the projected field of irradiation. The same shadow was observed in the contralateral lung field one month later. Gynecomastia and an elevated level of serum HCG were noticed during hospitalization. The patient died and an autopsy was performed. Histopathological examination upon autopsy confirmed a large cell carcinoma of the lung which stained positively for HCG with an immunoenzyme labelling technique using the PAP method. Marked fibrosis and thickening of the alveolar septae were histologically demonstrated in the projected field of irradiation and the contralateral field where chest x-rays showed the pneumonia-like shadow. (author).

  11. Heights integrated model as instrument for simulation of hydrodynamic, radiation transport, and heat conduction phenomena of laser-produced plasma in EUV applications.

    Energy Technology Data Exchange (ETDEWEB)

    Sizyuk, V.; Hassanein, A.; Morozov, V.; Sizyuk, T.; Mathematics and Computer Science

    2007-01-16

    The HEIGHTS integrated model has been developed as an instrument for simulation and optimization of laser-produced plasma (LPP) sources relevant to extreme ultraviolet (EUV) lithography. The model combines three general parts: hydrodynamics, radiation transport, and heat conduction. The first part employs a total variation diminishing scheme in the Lax-Friedrich formulation (TVD-LF); the second part, a Monte Carlo model; and the third part, implicit schemes with sparse matrix technology. All model parts consider physical processes in three-dimensional geometry. The influence of a generated magnetic field on laser plasma behavior was estimated, and it was found that this effect could be neglected for laser intensities relevant to EUV (up to {approx}10{sup 12} W/cm{sup 2}). All applied schemes were tested on analytical problems separately. Benchmark modeling of the full EUV source problem with a planar tin target showed good correspondence with experimental and theoretical data. Preliminary results are presented for tin droplet- and planar-target LPP devices. The influence of three-dimensional effects on EUV properties of source is discussed.

  12. Lightning-produced NOx in an explicit electrical scheme tested in a Stratosphere-Troposphere Experiment: Radiation, Aerosols, and Ozone case study

    Science.gov (United States)

    Barthe, Christelle; Pinty, Jean-Pierre; Mari, CéLine

    2007-02-01

    An explicit lightning-produced nitrogen oxide (LNOx) scheme has been implemented in a 3-D mesoscale model. The scheme is based on the simulation of the electrical state of the cloud and provides a prediction of the temporal and spatial distribution of the lightning flashes. The frequency and the 3-D morphology of the lightning flashes are captured realistically so fresh nitrogen oxide molecules can be added along the complex flash path as a function of the pressure, as suggested by results from laboratory experiments. The scheme is tested on the 10 July 1996 Stratosphere-Troposphere Experiment: Radiation, Aerosols, and Ozone (STERAO) storm. The model reproduces many features of the observed increase of electrical activity and LNOx flux density between the multicell and supercell stages. LNOx dominates the NOx budget in the upper part of the cells with instantaneous peak concentrations exceeding 4 ppbv, as observed. The computed flux of NOx across the anvil shows a mean value of 6 mol m-2 s-1 during the last 90 min of the simulation. This value is remarkably stable and compares favorably with the observations.

  13. Macroeconomic shocks and firms' labor adjustment

    DEFF Research Database (Denmark)

    Eriksson, Tor

    2013-01-01

    This article discusses some recent research which aims at producing evidence on how firms adjust their employment in response to output shocks using micro-level data and with a particular focus on the relationship between worker and job flows. The evidence presented is mainly based on Danish data...

  14. Clarifying the Role of Reactive Oxygen Species and Reported Effects of Low-Dose Ionizing Radiation on Cells - Clarifying the Role of Reactive Oxygen Species in Producing the Reported Effects of Low-Dose Ionizing Radiation on Cells

    Energy Technology Data Exchange (ETDEWEB)

    Willey, Neil J. [Centre for Research In Biosciences, University of the West of England, Coldharbour Lane, Frenchay, Bristol BS16 1QY (United Kingdom)

    2014-07-01

    Chronic low doses of ionizing radiation (IR) to cells, such as those that occur in contaminated environments, are widely reported to produce a variety of effects, from adverse effects to no effects to positive effects. In addition, bystander effects have been reported in some studies. For only relatively few of these effects have mechanistic explanations been reported but in many of those for which they have, reactive oxygen species (ROS) and/or the anti-oxidants that help to control their effects, have often been suggested to have a role. In general, it is assumed that either radiolysis of water or stress due to IR cause an increase in ROS and/or anti-oxidant activity, and hence the observed effects. The role of ROS in producing the effects reported at chronic low doses of radiation has infrequently been tested at either a theoretical or experimental level. Here we use a dynamic model of anti-oxidant capacity in cells to test the theoretical underpinnings of the ROS hypothesis together with genomic and proteomic experiments using Arabidopsis thaliana to test the molecular effects of IR in cells. The published model we have constructed for testing the interaction of IR and anti-oxidant systems (Smith et al, 2012) first calculates the amount of ROS produced by IR. Overall, at the dose rates that occur in contaminated environments the amount of ROS produced by IR is extremely small, certainly much smaller than is routinely produced in a cell during many metabolic processes. ROS from respiration leak out of mitochondria at significant rates and in plant cells ROS also leak out of photo-synthesizing chloroplasts. Although there is a variety of anti-oxidants in many cells, the nexus of their capacity is glutathione (GSH) which ultimately derives its reducing power from NADPH. We thus modeled the anti-oxidative capacity of a cell from the activity GSH and used predicted concentrations of ROS from IR to calculate the oxidative stress that they would cause via the

  15. Experimental Shock Transformation of Gypsum to Anhydrite: A New Low Pressure Regime Shock Indicator

    Science.gov (United States)

    Bell, Mary S.; Zolensky, Michael E.

    2011-01-01

    The shock behavior of gypsum is important in understanding the Cretaceous/Paleogene event and other terrestrial impacts that contain evaporite sediments in their targets (e.g., Mars Exploration Rover Spirit detected sulfate at Gusev crater, [1]). Most interest focuses on issues of devolatilization to quantify the production of SO2 to better understand its role in generating a temporary atmosphere and its effects on climate and biota [2,3]. Kondo and Ahrens [4] measured induced radiation emitted from single crystal gypsum shocked to 30 and 40 GPa. They observed greybody emission spectra corresponding to temperatures in the range of 3,000 to 4,000 K that are a factor of 2 to 10 times greater than calculated pressure-density energy equation of state temperatures (Hugoniot) and are high enough to melt gypsum. Chen et al. [5] reported results of shock experiments on anhydrite, gypsum, and mixtures of these phases with silica. Their observations indicated little or no devolatilization of anhydrite shocked to 42 GPa and that the fraction of sulfur, by mass, that degassed is approx.10(exp -2) of theoretical prediction. In another report of shock experiments on calcite, anhydrite, and gypsum, Badjukov et al. [6] observed only intensive plastic deformation in anhydrite shock loaded at 63 GPa, and gypsum converted to anhydrite when shock loaded at 56 GPa but have not experimentally shocked gypsum in a step-wise manner to constrain possible incipient transformation effects. Schmitt and Hornemann [7] shock loaded anhydrite and quartz to a peak pressure of 60 GPa and report the platy anhydrite grains were completely pseudomorphed by small crystallized anhydrite grains. However, no evidence of interaction between the two phases could be observed and they suggested that recrystallization of anhydrite grains is the result of a solid-state transformation. They concluded that significant decomposition of anhydrite requires shock pressures higher than 60 GPa. Gupta et al. [8

  16. Shock Isolation Elements Testing for High Input Loadings. Volume II. Foam Shock Isolation Elements.

    Science.gov (United States)

    SHOCK ABSORBERS ), (*GUIDED MISSILE SILOS, SHOCK ABSORBERS ), (*EXPANDED PLASTICS, (*SHOCK(MECHANICS), REDUCTION), TEST METHODS, SHOCK WAVES, STRAIN(MECHANICS), LOADS(FORCES), MATHEMATICAL MODELS, NUCLEAR EXPLOSIONS, HARDENING.

  17. Strong shock wave and areal mass oscillations associated with impulsive loading of planar laser targets

    International Nuclear Information System (INIS)

    Velikovich, A.L.; Schmitt, A.J.; Metzler, N.; Gardner, J.H.

    2003-01-01

    When a rippled surface of a planar target is irradiated with a short (subnanosecond) laser pulse, the shock wave launched into the target and the mass distribution of the shocked plasma will oscillate. These oscillations are found to be surprisingly strong compared, for example, to the case when the laser radiation is not turned off but rather keeps pushing the shock wave into the target. Being stronger than the areal mass oscillations due to ablative Richtmyer-Meshkov instability and feedout in planar targets, which have recently been observed at the Naval Research Laboratory (NRL) [Aglitskiy et al., Phys. Plasmas 9, 2264 (2002)], these oscillations should therefore be directly observable with the same diagnostic technique. Irradiation of a target with a short laser pulse represents a particular case of an impulsive loading, a fast release of finite energy in a thin layer near the surface of a target. Renewed interest to the impulsive loading in the area of direct-drive laser fusion is due to the recent proposals of using a short pulse prior to the drive pulse to make the target more resistant to laser imprint and Rayleigh-Taylor growth. Impulsive loading produces a shock wave that propagates into the target and is immediately followed by an expansion wave, which gradually reduces the shock strength. If the irradiated surface is rippled, then, while the shock wave propagates through the target, its modulation amplitude grows, exceeding the initial ripple amplitude by a factor of 2 or more. The oscillating areal mass reaches the peak values that exceed the initial mass modulation amplitude (density times ripple height) by a factor of 5-7 or more, and reverses its phase several times after the laser pulse is over. The oscillatory growth is more pronounced in fluids with higher shock compressibility and is probably related to the Vishniac's instability of a blast wave. Frequency of the oscillations is determined by the speed of sound in the shocked material, and

  18. Intense laser driven collision-less shock and ion acceleration in magnetized plasmas

    Science.gov (United States)

    Mima, K.; Jia, Q.; Cai, H. B.; Taguchi, T.; Nagatomo, H.; Sanz, J. R.; Honrubia, J.

    2016-05-01

    The generation of strong magnetic field with a laser driven coil has been demonstrated by many experiments. It is applicable to the magnetized fast ignition (MFI), the collision-less shock in the astrophysics and the ion shock acceleration. In this paper, the longitudinal magnetic field effect on the shock wave driven by the radiation pressure of an intense short pulse laser is investigated by theory and simulations. The transition of a laminar shock (electro static shock) to the turbulent shock (electromagnetic shock) occurs, when the external magnetic field is applied in near relativistic cut-off density plasmas. This transition leads to the enhancement of conversion of the laser energy into high energy ions. The enhancement of the conversion efficiency is important for the ion driven fast ignition and the laser driven neutron source. It is found that the total number of ions reflected by the shock increases by six time when the magnetic field is applied.

  19. The characteristic response of whistler mode waves to interplanetary shocks

    Science.gov (United States)

    Yue, C.; Chen, L.; Bortnik, J.; Ma, Q.; Thorne, R. M.; Angelopoulos, V.; Li, J.; An, X.; Zhou, C.

    2017-12-01

    Magnetospheric whistler mode waves play a key role in regulating the dynamics of the electron radiation belts. Recent satellite observations indicate a significant influence of interplanetary (IP) shocks on whistler mode wave power in the inner magnetosphere. In this study, we statistically investigate the response of whistler mode chorus and plasmaspheric hiss to IP shocks based on Van Allen Probes and THEMIS satellite observations. Immediately after the IP shock arrival, chorus wave power is usually intensified, often at dawn, while plasmaspheric hiss wave power predominantly decreases near the dayside but intensifies near the nightside. We conclude that chorus wave intensification outside the plasmasphere is probably associated with the suprathermal electron flux enhancement caused by the IP shock. On the other hand, the solar wind dynamic pressure increase changes the magnetic field configuration to favor ray penetration into the nightside and promote ray refraction away from the dayside, explaining the magnetic local time (MLT) dependent responses of plasmaspheric hiss waves following IP shock arrivals.

  20. Wave and particle evolution downstream of quasi-perpendicular shocks

    Science.gov (United States)

    Mckean, M. E.; Omidi, N.; Krauss-Varban, D.; Karimabadi, H.

    1995-01-01

    Distributions of ions heated in quasi-perpendicular bow shocks have large perpendicular temperature anisotropies that provide free energy for the growth of Alfven ion cyclotron (AIC) and mirror waves. These modes are often obsreved in the Earth's magnetosheath. Using two-dimensional hybrid simulations, we show that these waves are produced near the shock front and convected downstream rather than being produced locally downstream. The wave activity reduces the proton anisotropy to magnetosheath levels within a few tens of gyroradii of the shock but takes significantly longer to reduce the anisotropy of He(++) ions. The waves are primarily driven by proton anisotropy and the dynamics of the helium ions is controlled by the proton waves. Downstream of high Mach number shocks, mirror waves compete effectively with AIC waves. Downstream of low Mach number shocks, AIC waves dominate.

  1. Counseling For Future Shock

    Science.gov (United States)

    Morgan, Lewis B.

    1974-01-01

    In this article the author looks at some of the searing prophecies made by Alvin Toffler in his book Future Shock and relates them to the world of the professional counselor and the clientele the counselor attempts to serve. (Author)

  2. Life shocks and homelessness.

    Science.gov (United States)

    Curtis, Marah A; Corman, Hope; Noonan, Kelly; Reichman, Nancy E

    2013-12-01

    We exploited an exogenous health shock-namely, the birth of a child with a severe health condition-to investigate the effect of a life shock on homelessness in large cities in the United States as well as the interactive effects of the shock with housing market characteristics. We considered a traditional measure of homelessness, two measures of housing instability thought to be precursors to homelessness, and a combined measure that approximates the broadened conceptualization of homelessness under the 2009 Homeless Emergency Assistance and Rapid Transition to Housing Act (2010). We found that the shock substantially increases the likelihood of family homelessness, particularly in cities with high housing costs. The findings are consistent with the economic theory of homelessness, which posits that homelessness results from a conjunction of adverse circumstances in which housing markets and individual characteristics collide.

  3. Unlimited Relativistic Shock Surfing Acceleration

    International Nuclear Information System (INIS)

    Ucer, D.; Shapiro, V. D.

    2001-01-01

    Nonrelativistic shock surfing acceleration at quasiperpendicular shocks is usually considered to be a preacceleration mechanism for slow pickup ions to initiate diffusive shock acceleration. In shock surfing, the particle accelerates along the shock front under the action of the convective electric field of the plasma flow. However, the particle also gains kinetic energy normal to the shock and eventually escapes downstream. We consider the case when ions are accelerated to relativistic velocities. In this case, the ions are likely to be trapped for infinitely long times, because the energy of bounce oscillations tends to decrease during acceleration. This suggests the possibility of unlimited acceleration by shock surfing

  4. High Temperature Phenomena in Shock Waves

    CERN Document Server

    2012-01-01

    The high temperatures generated in gases by shock waves give rise to physical and chemical phenomena such as molecular vibrational excitation, dissociation, ionization, chemical reactions and inherently related radiation. In continuum regime, these processes start from the wave front, so that generally the gaseous media behind shock waves may be in a thermodynamic and chemical non-equilibrium state. This book presents the state of knowledge of these phenomena. Thus, the thermodynamic properties of high temperature gases, including the plasma state are described, as well as the kinetics of the various chemical phenomena cited above. Numerous results of measurement and computation of vibrational relaxation times, dissociation and reaction rate constants are given, and various ionization and radiative mechanisms and processes are presented. The coupling between these different phenomena is taken into account as well as their interaction with the flow-field. Particular points such as the case of rarefied flows an...

  5. Commercial fish price shock behaviour in Akwa Ibom State ...

    African Journals Online (AJOL)

    Commercial fish price shock behaviour in Akwa Ibom State, Southern Nigeria. ... Username, Password, Remember me, or Register ... Producer – consumer price behaviour in the long run depends on several factors. This study tested for the ...

  6. ISEE observations of radiation at twice the solar wind plasma frequency

    International Nuclear Information System (INIS)

    Lacombe, C.; Harvey, C.C.; Hoang, S.

    1988-01-01

    Radiation produced in the vicinity of the Earth's bow shock at twice the solar wind electron plasma frequency f p is seen by both ISEE-1 and ISEE-3, respectively at about 20 and about 200 R E from the Earth. This electromagnetic radiation is due to the presence, in the electron foreshock, of electrons reflected and accelerated at the Earth's bow shock. We show that the source is near the upstream boundary of the foreshock, the surface where the magnetic field lines are tangent to the bow shock. A typical diameter of the source is 120-150 R E . Emissivity is given. The angular size of the source, seen by ISEE-3, is increased by scattering of the 2f p radio waves on the solar wind density fluctuations. We examine whether the bandwidth and directivity predicted by current source models are consistent with our observations

  7. X-RAY EMISSION FROM SUPERNOVAE IN DENSE CIRCUMSTELLAR MATTER ENVIRONMENTS: A SEARCH FOR COLLISIONLESS SHOCKS

    International Nuclear Information System (INIS)

    Ofek, E. O.; Gal-Yam, A.; Yaron, O.; Arcavi, I.; Fox, D.; Cenko, S. B.; Filippenko, A. V.; Bloom, J. S.; Sullivan, M.; Gnat, O.; Frail, D. A.; Horesh, A.; Kulkarni, S. R.; Corsi, A.; Quimby, R. M.; Gehrels, N.; Nugent, P. E.; Kasliwal, M. M.; Bildsten, L.; Poznanski, D.

    2013-01-01

    The optical light curve of some supernovae (SNe) may be powered by the outward diffusion of the energy deposited by the explosion shock (the so-called shock breakout) in optically thick (τ ∼> 30) circumstellar matter (CSM). Recently, it was shown that the radiation-mediated and radiation-dominated shock in an optically thick wind must transform into a collisionless shock and can produce hard X-rays. The X-rays are expected to peak at late times, relative to maximum visible light. Here we report on a search, using Swift/XRT and Chandra, for X-ray emission from 28 SNe that belong to classes whose progenitors are suspected to be embedded in dense CSM. Our sample includes 19 Type IIn SNe, one Type Ibn SN, and eight hydrogen-poor superluminous SNe (SLSN-I such as SN 2005ap). Two SNe (SN 2006jc and SN 2010jl) have X-ray properties that are roughly consistent with the expectation for X-rays from a collisionless shock in optically thick CSM. However, the X-ray emission from SN 2006jc can also be explained as originating in an optically thin region. Thus, we propose that the optical light curve of SN 2010jl is powered by shock breakout in CSM. We suggest that two other events (SN 2010al and SN 2011ht) were too X-ray bright during the SN maximum optical light to be explained by the shock-breakout model. We conclude that the light curves of some, but not all, SNe IIn/Ibn are powered by shock breakout in CSM. For the rest of the SNe in our sample, including all of the SLSN-I events, our X-ray limits are not deep enough and were typically obtained too early (i.e., near the SN maximum light) for definitive conclusions about their nature. Late-time X-ray observations are required in order to further test whether these SNe are indeed embedded in dense CSM. We review the conditions required for a shock breakout in a wind profile. We argue that the timescale, relative to maximum light, for the SN to peak in X-rays is a probe of the column density and the density profile above the

  8. Technology shocks matter

    OpenAIRE

    Jonas D. M. Fisher

    2002-01-01

    This paper uses the neoclassical growth model to identify the effects of technological change on the US business cycle. In the model there are two sources of technological change: neutral, which effects the production of all goods homogeneously, and investment-specific. Investment-specific shocks are the unique source of the secular trend in the real price of investment goods, while shocks to both kinds of technology are the only factors which affect labor productivity in the long run. Consis...

  9. Efficient models for photoionization produced by non-thermal gas discharges in air based on radiative transfer and the Helmholtz equations

    International Nuclear Information System (INIS)

    Bourdon, A; Pasko, V P; Liu, N Y; Celestin, S; Segur, P; Marode, E

    2007-01-01

    This paper presents formulation of computationally efficient models of photoionization produced by non-thermal gas discharges in air based on three-group Eddington and improved Eddington (SP 3 ) approximations to the radiative transfer equation, and on effective representation of the classic integral model for photoionization in air developed by Zheleznyak et al (1982) by a set of three Helmholtz differential equations. The reported formulations represent extensions of ideas advanced recently by Segur et al (2006) and Luque et al (2007), and allow fast and accurate solution of photoionization problems at different air pressures for the range 0.1 O 2 O 2 is the partial pressure of molecular oxygen in air in units of Torr ( p O 2 = 150 Torr) at atmospheric pressure) and R in cm is an effective geometrical size of the physical system of interest. The presented formulations can be extended to other gases and gas mixtures subject to availability of related emission, absorption and photoionization coefficients. The validity of the developed models is demonstrated by performing direct comparisons of the results from these models and results obtained from the classic integral model. Specific validation comparisons are presented for a set of artificial sources of photoionizing radiation with different Gaussian dimensions, and for a realistic problem involving development of a double-headed streamer at ground pressure. The reported results demonstrate the importance of accurate definition of the boundary conditions for the photoionization production rate for the solution of second order partial differential equations involved in the Eddington, SP 3 and the Helmholtz formulations. The specific algorithms derived from the classic photoionization model of Zheleznyak et al (1982), allowing accurate calculations of boundary conditions for differential equations involved in all three new models described in this paper, are presented. It is noted that the accurate formulation of

  10. Diagnostics of laser-produced plasmas

    Directory of Open Access Journals (Sweden)

    Batani Dimitri

    2016-12-01

    Full Text Available We present the general challenges of plasma diagnostics for laser-produced plasmas and give a few more detailed examples: spherically bent crystals for X-ray imaging, velocity interferometers (VISAR for shock studies, and proton radiography.

  11. Apparatus for reducing shock and overpressure

    Science.gov (United States)

    Walter, C.E.

    1975-01-28

    An apparatus for reducing shock and overpressure is particularly useful in connection with the sequential detonation of a series of nuclear explosives under ground. A coupling and decoupling arrangement between adjacent nuclear explosives in the tubing string utilized to emplace the explosives is able to support lower elements on the string but yields in a manner which absorbs energy when subjected to the shock wave produced upon detonation of one of the explosives. Overpressure is accomodated by an arrangement in the string which provides an additional space into which the pressurized material can expand at a predetermined overpressure. (10 claims)

  12. Electron Shock Ignition of Inertial Fusion Targets

    International Nuclear Information System (INIS)

    Shang, W. L.; Betti, R.; Hu, S. X.; Woo, K.; Hao, L.

    2017-01-01

    Here, it is shown that inertial fusion targets designed with low implosion velocities can be shock ignited using laser–plasma interaction generated hot electrons (hot-e) to obtain high-energy gains. These designs are robust to multimode asymmetries and are predicted to ignite even for significantly distorted implosions. Electron shock ignition requires tens of kilojoules of hot-e, which can only be produced on a large laser facility like the National Ignition Facility, with the laser to hot-e conversion efficiency greater than 10% at laser intensities ~10 16 W/cm 2 .

  13. Biophoton emission induced by heat shock.

    Directory of Open Access Journals (Sweden)

    Katsuhiro Kobayashi

    Full Text Available Ultraweak biophoton emission originates from the generation of reactive oxygen species (ROS that are produced in mitochondria as by-products of cellular respiration. In healthy cells, the concentration of ROS is minimized by a system of biological antioxidants. However, heat shock changes the equilibrium between oxidative stress and antioxidant activity, that is, a rapid rise in temperature induces biophoton emission from ROS. Although the rate and intensity of biophoton emission was observed to increase in response to elevated temperatures, pretreatment at lower high temperatures inhibited photon emission at higher temperatures. Biophoton measurements are useful for observing and evaluating heat shock.

  14. Shock-resistant scintillation detector

    International Nuclear Information System (INIS)

    Novak, W.P.

    1979-01-01

    A unique scintillation detector unit is disclosed which employs a special light transfer and reflector means that encases and protects the scintillator crystal against high g forces. The light transfer means comprises a flexible silicon rubber optical material bonded between the crystal and the optical window and having an axial thickness sufficient to allow the scintillator to move axially inside the container under high g forces without destroying the bonds. The reflector means comprises a soft elastic silicone rubber sleeve having a multiplicity of closely arranged tapered protrusions radiating toward and engaging the periphery of the scintillator crystal to cushion shocks effectively and having a reflective material, such as aluminum oxide powder, in the spaces between the protrusions. The reflector means provides improved shock absorption because of the uniform support and cushioning action of the protrusions and also provides the detector with high efficiency. The silicon rubber composition is specially compounded to include a large amount of aluminum oxide which enables the rubber to function effectively as a light reflector

  15. DESTRUCTION OF INTERSTELLAR DUST IN EVOLVING SUPERNOVA REMNANT SHOCK WAVES

    International Nuclear Information System (INIS)

    Slavin, Jonathan D.; Dwek, Eli; Jones, Anthony P.

    2015-01-01

    Supernova generated shock waves are responsible for most of the destruction of dust grains in the interstellar medium (ISM). Calculations of the dust destruction timescale have so far been carried out using plane parallel steady shocks, however, that approximation breaks down when the destruction timescale becomes longer than that for the evolution of the supernova remnant (SNR) shock. In this paper we present new calculations of grain destruction in evolving, radiative SNRs. To facilitate comparison with the previous study by Jones et al., we adopt the same dust properties as in that paper. We find that the efficiencies of grain destruction are most divergent from those for a steady shock when the thermal history of a shocked gas parcel in the SNR differs significantly from that behind a steady shock. This occurs in shocks with velocities ≳200 km s −1 for which the remnant is just beginning to go radiative. Assuming SNRs evolve in a warm phase dominated ISM, we find dust destruction timescales are increased by a factor of ∼2 compared to those of Jones et al., who assumed a hot gas dominated ISM. Recent estimates of supernova rates and ISM mass lead to another factor of ∼3 increase in the destruction timescales, resulting in a silicate grain destruction timescale of ∼2–3 Gyr. These increases, while not able to resolve the problem of the discrepant timescales for silicate grain destruction and creation, are an important step toward understanding the origin and evolution of dust in the ISM

  16. Electronic-state distribution of Ar* produced from Ar+(2P3/2)/2e- collisional radiative recombination in an argon flowing afterglow

    International Nuclear Information System (INIS)

    Tsuji, Masaharu; Matsuzaki, Toshinori; Tsuji, Takeshi

    2002-01-01

    The Ar + /2e - collisional radiative recombination has been studied by observing UV and visible emissions of Ar* in an Ar flowing afterglow. In order to clarify recombination mechanism, the Ar + ( 2 P 3/2 ) spin-orbit component was selected by using a filter gas of the Ar + ( 2 P 1/2 ) component. Spectral analysis indicated that 34 Ar*(4p, 4d, 5p, 5d, 6s, 6p, 6d, 4p ' , 4d ' , 5p ' , 5d ' , 6s ' ) states in the 13.08-15.33 eV range are produced. The electronic-state distribution decreased with an increase in the excitation energy of Ar*, which was expressed by a Boltzmann electronic temperature of 0.54 eV. The formation ratios of the 4p: 4d + 5p + 5d + 6s + 6p + 6d: 4p ' : 4d ' + 5p ' + 5d ' + 6s ' states were 43%, 2.8%, 54%, and 0.31%, respectively. The high formation ratio of the 4p ' state having an Ar + ( 2 P 1/2 ) ion core in the Ar + ( 2 P 3/2 )/2e - recombination indicated that such a two-electron process as an electron transfer to an inner 3p orbital followed by excitation of a 3p electron to an outer 4p orbital occurs significantly. The higher formation ratios of 4d + 5p + 5d + 6s + 6p + 6d than those of 4d ' + 5p ' + 5d ' + 6s ' led us to conclude the formation of these upper states dominantly proceeds through one electron transfer to an outer nl orbital of Ar + ( 2 P 3/2 )

  17. On ion injection at quasiparallel shocks

    International Nuclear Information System (INIS)

    Scholer, M.; Kucharek, H.; Kato, C.

    2002-01-01

    A large number of numerical experiments has been performed in order to study the interaction of interstellar pickup protons and helium ions with quasiparallel collisionless shocks. The shocks are modeled by a one-dimensional hybrid simulation method which treats the ions as macroparticles and the electrons as a massless fluid. Solar wind alpha particles and pickup protons are included self-consistently. In addition, the particle splitting method is used for the solar wind ions so that the distribution function can be followed over more than 10 orders of magnitude. A large part of the pickup ion distribution is reflected; the reflection efficiency is very high, and can reach in cases where the pickup ion density is low as much as 50%-60%. The reflection efficiency is almost independent of magnetic field-shock normal angle. This indicates that magnetic mirroring is unimportant and does not lead to larger reflection efficiencies. The reflection efficiency of pickup protons rapidly decreases when the pickup ion density exceeds a few percent of the solar wind density. An addition of 25% pickup protons decreases the reflection coefficient for these ions to ∼10%. This represents the fact that a quasiparallel shock cannot be considered as being uncoupled from the upstream region: at high additions of pickup ions the shock structure is changed in such a way as to reflect less pickup ions. The intensity of diffuse ions upstream of a quasiparallel shock does not depend on the temperature of the core distribution. Within the framework of the present model even solar wind distributions with a hard power law tail do not produce higher intensities of diffuse ions. It is argued that this can be understood by the fact that the intrinsic self-consistency between the processes in the upstream region and at the shock transition determines the injection and reflection properties of the core solar wind distribution

  18. Shock wave interaction with pulsed glow discharge and afterglow plasmas

    International Nuclear Information System (INIS)

    Podder, N.K.; LoCascio, A.C.

    2009-01-01

    Acoustic shock waves are launched by the spark-discharge of a high voltage capacitor in pulsed glow discharge and afterglow plasmas. The glow discharge section of the shock tube is switched on for a period of less than one second at a time, during which a shock wave is launched starting with a large delay between the plasma switch-on and the shock-launch. In the subsequent runs this delay is decremented in equal time intervals up to the plasma switch-on time. A photo acoustic deflection method sensitive to the density gradient of the shock wave is used to study the propagating shock structure and velocity in the igniting plasma. A similar set of measurements are also performed at the plasma switch-off, in which the delay time is incremented in equal time intervals from the plasma switch-off time until the afterglow plasma fully neutralizes itself into the room-temperature gas. Thus, complete time histories of the shock wave propagation in the igniting plasma, as well as in the afterglow plasma, are produced. In the igniting plasma, the changes in the shock-front velocity and dispersion are found to be a strong non-linear function of delay until a saturation point is reached. On the other hand, in the afterglow plasma the trend has been opposite and reversing towards the room temperature values. The observed shock wave properties in both igniting and afterglow plasmas correlate well with the inferred temperature changes in the two plasmas

  19. Shock circle model for ejector performance evaluation

    International Nuclear Information System (INIS)

    Zhu, Yinhai; Cai, Wenjian; Wen, Changyun; Li, Yanzhong

    2007-01-01

    In this paper, a novel shock circle model for the prediction of ejector performance at the critical mode operation is proposed. By introducing the 'shock circle' at the entrance of the constant area chamber, a 2D exponential expression for velocity distribution is adopted to approximate the viscosity flow near the ejector inner wall. The advantage of the 'shock circle' analysis is that the calculation of ejector performance is independent of the flows in the constant area chamber and diffuser. Consequently, the calculation is even simpler than many 1D modeling methods and can predict the performance of critical mode operation ejectors much more accurately. The effectiveness of the method is validated by two experimental results reported earlier. The proposed modeling method using two coefficients is shown to produce entrainment ratio, efficiency and coefficient of performance (COP) accurately and much closer to experimental results than those of 1D analysis methods

  20. Shock Tube as an Impulsive Application Device

    Directory of Open Access Journals (Sweden)

    Soumya Ranjan Nanda

    2017-01-01

    Full Text Available Current investigations solely focus on application of an impulse facility in diverse area of high-speed aerodynamics and structural mechanics. Shock tube, the fundamental impulse facility, is specially designed and calibrated for present objectives. Force measurement experiments are performed on a hemispherical test model integrated with the stress wave force balance. Similar test model is considered for heat transfer measurements using coaxial thermocouple. Force and heat transfer experiments demonstrated that the strain gauge and thermocouple have lag time of 11.5 and 9 microseconds, respectively. Response time of these sensors in measuring the peak load is also measured successfully using shock tube facility. As an outcome, these sensors are found to be suitable for impulse testing. Lastly, the response of aluminum plates subjected to impulsive loading is analyzed by measuring the in-plane strain produced during deformation. Thus, possibility of forming tests in shock is also confirmed.