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Sample records for nuclear fragmentation model

  1. Nuclear fragmentation

    International Nuclear Information System (INIS)

    Chung, K.C.

    1989-01-01

    An introduction to nuclear fragmentation, with emphasis in percolation ideas, is presented. The main theoretical models are discussed and as an application, the uniform expansion approximation is presented and the statistical multifragmentation model is used to calculate the fragment energy spectra. (L.C.)

  2. Anomalous nuclear fragments

    International Nuclear Information System (INIS)

    Karmanov, V.A.

    1983-01-01

    Experimental data are given, the status of anomalon problem is discussed, theoretical approaches to this problem are outlined. Anomalons are exotic objects formed following fragmentation of nuclei-targets under the effect of nuclei - a beam at the energy of several GeV/nucleon. These nuclear fragments have an anomalously large cross section of interaction and respectively, small free path, considerably shorter than primary nuclei have. The experimental daa are obtained in accelerators following irradiation of nuclear emulsions by 16 O, 56 Fe, 40 Ar beams, as well as propane by 12 C beams. The experimental data testify to dependence of fragment free path on the distance L from the point of the fragment formation. A decrease in the fragment free path is established more reliably than its dependence on L. The problem of the anomalon existence cannot be yet considered resolved. Theoretical models suggested for explanation of anomalously large cross sections of nuclear fragment interaction are variable and rather speculative

  3. Explosion-evaporation model for fragment production in intermediate-energy nuclear collisions

    International Nuclear Information System (INIS)

    Fai, G.; Randrup, J.

    1981-01-01

    Nuclear collisions at intermediate energies may create transient systems of hot nuclear matter that decay into many nuclear fragments. The disassembly of such a nuclear fireball is described as a two-stage process. In the primary explosion stage the system quickly fragments into nucleons and composite nuclei according to the available phase space. The explosion produces excited nuclei with half-lives longer than the time associated with the breakup. In the secondary evaporation stage, these nuclei decay, first by sequential emission of light particles (neutrons, protons, alphas), later by electromagnetic radiation. The secondary stage in general changes the relative abundancies of the various fragment species. This general feature makes it essential to take account of the composite fragments before using d/p as a measure of the entropy of the initial source. The formation of unbound nuclei at the explosion stage also has the desirable effect of enhancing the final abundancies of particularly stable nuclei, e.g., 4 He. For neutron-excessive sources the presence of composite nuclei amplifies the ratio of observed neutrons and protons; this effect persists for heavier mirror systems. Predictions of the model are qualitatively compared to available experimental data. The model offers a convenient way to augment existing dynamical models, such as intra-nuclear cascade and nuclear fluid dynamics, to yield actual nuclear fragments rather than merely matter distributions

  4. Elaboration of a model of the nuclear fragmentation and application to the method of isotopic separation of projectile fragments

    International Nuclear Information System (INIS)

    Gaimard, J.J.

    1990-10-01

    In this thesis the experimental results on the cross sections for the production of 36 P in the fragmentation of 403 MeV/u 40 Ar on a carbon target are presented. Furthermore some models of the nuclear fragmentation are elaborated and compared by means of experimental data for the production of gold and cerium isotopes in the reaction 12 C+ 209 Bi at 400 MeV/u, of chlorine, sulfur, aluminium, magnesium, and oxygen isotopes in the reactions 40 Ar+ 12 C at 600 MeV/u and 48 Ca+ 9 Be at 212 MeV/u, and of cobalt, manganese, vanadium, and scandium isotopes together with the charge distributions for A=43 and A=44 in the reactions 40 Ar+ 64 Cu at 2 GeV/u and 56 Fe+ 12 C at 600 MeV/u. (HSI)

  5. Nuclear fragmentation by nucleation approach

    International Nuclear Information System (INIS)

    Chung, K.C.

    1992-01-01

    The nucleation model is used to simulate nuclear fragmentation processes. The critical value of the effective interaction radius is shown to vary linearly with the expansion factor α. The calculated mass and charge distributions are compared with some experimental data. (author)

  6. Research of nuclear fragmentation characteristics

    International Nuclear Information System (INIS)

    Richert, J.

    1989-01-01

    Motivations for the study of nuclear fragmentation are presented. Different models and methods which were developed in the past are reviewed, critically discussed and confronted in connection with the experimental information gathered over the past years. Specific aspects related to the onset of the process, its characteristics and the mechanism which governs it are discussed [fr

  7. Fragmentation processes in nuclear reactions

    International Nuclear Information System (INIS)

    Baur, G.; Roesel, F.; Trautmann, D.; Shyam, R.

    1983-10-01

    Fragmentation processes in nuclear collisions are reviewed. The main emphasis is put on light ion breakup at nonrelativistic energies. The post- and prior-form DWBA theories are discussed. The post-form DWBA, appropriate for the ''spectator breakup'' describes elastic as well as inelastic breakup modes. This theory can also account for the stripping to unbound states. The theoretical models are compared to typical experimental results to illustrate the various possible mechanisms. It is discussed, how breakup reactions can be used to study high-lying single particle strength in the continuum; how it can yield information about momentum distributions of fragments in the nucleus. (orig.)

  8. Fragmentation processes in nuclear reactions

    International Nuclear Information System (INIS)

    Legrain, R.

    1984-08-01

    Projectile and nuclear fragmentation are defined and processes referred to are recalled. The two different aspects of fragmentation are considered but the emphasis is also put on heavy ion induced reactions. The preliminary results of an experiment performed at GANIL to study peripheral heavy ions induced reactions at intermediate energy are presented. The results of this experiment will illustrate the characteristics of projectile fragmentation and this will also give the opportunity to study projectile fragmentation in the transition region. Then nuclear fragmentation is considered which is associated with more central collisions in the case of heavy ion induced reactions. This aspect of fragmentation is also ilustrated with two heavy ion experiments in which fragments emitted at large angle have been observed

  9. Azimuthal Anisotropies in Nuclear Fragmentation

    International Nuclear Information System (INIS)

    Dabrowska, A.; Szarska, M.; Trzupek, A.; Wolter, W.; Wosiek, B.

    2002-01-01

    The directed and elliptic flow of fragments emitted from the excited projectile nuclei has been observed for 158 AGeV Pb collisions with the lead and plastic targets. For comparison the flow analysis has been performed for 10.6 AGeV Au collisions with the emulsion target. The strong directed flow of heaviest fragments is found. Light fragments exhibit directed flow opposite to that of heavy fragments. The elliptic flow for all multiply charged fragments is positive and increases with the charge of the fragment. The observed flow patterns in the fragmentation of the projectile nucleus are practically independent of the mass of the target nucleus and the collision energy. Emission of fragments in nuclear multifragmentation shows similar, although weaker, flow effects. (author)

  10. Fragment emission from modestly excited nuclear systems

    Energy Technology Data Exchange (ETDEWEB)

    Lou, Y. [Indiana Univ., Bloomington, IN (United States). Dept. of Chemistry]|[Indiana Univ., Bloomington, IN (United States). Cyclotron Facility; Souza, R.T. de [Indiana Univ., Bloomington, IN (United States). Dept. of Chemistry]|[Indiana Univ., Bloomington, IN (United States). Cyclotron Facility; Chen, S.L. [Indiana Univ., Bloomington, IN (United States). Dept. of Chemistry]|[Indiana Univ., Bloomington, IN (United States). Cyclotron Facility; Cornell, E.W. [Indiana Univ., Bloomington, IN (United States). Dept. of Chemistry]|[Indiana Univ., Bloomington, IN (United States). Cyclotron Facility; Davin, B. [Indiana Univ., Bloomington, IN (United States). Dept. of Chemistry]|[Indiana Univ., Bloomington, IN (United States). Cyclotron Facility; Fox, D. [Indiana Univ., Bloomington, IN (United States). Dept. of Chemistry]|[Indiana Univ., Bloomington, IN (United States). Cyclotron Facility; Hamilton, T.M. [Indiana Univ., Bloomington, IN (United States). Dept. of Chemistry]|[Indiana Univ., Bloomington, IN (United States). Cyclotron Facility; Mcdonald, K. [Indiana Univ., Bloomington, IN (United States). Dept. of Chemistry]|[Indiana Univ., Bloomington, IN (United States). Cyclotron Facility; Tsang, M.B. [Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab.; Glasmacher, T. [Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab.; Dinius, J. [Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab.; Gelbke, C.K. [Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab.; Handzy, D.O. [Indiana Univ., Bloomington, IN (United States). Dept. of Chemistry]|[Indiana Univ., Bloomington, IN (United States). Cyclotron Facility]|[Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab.; Hsi, W.C.

    1996-07-08

    Fragment emission patterns occurring in nuclear systems of modest excitation are studied. Exclusive measurement of fragment emission in {sup 14}N+{sup 197}Au reactions at E/A=100, 130 and 156 MeV allows selection of central collisions where a single source dominates the decay. Low threshold measurement of IMF emission for these events allows investigation of the influence of detector threshold effects. The time scale of fragment emission is deduced using fragment-fragment velocity correlations. Comparisons are made to the predictions of a statistical decay model. (orig.).

  11. DLNA: a simple one-dimensional dynamical model as a possible interpretation of fragment size distribution in nuclear multifragmentation

    International Nuclear Information System (INIS)

    Lacroix, D.; Dayras, R.

    1996-08-01

    The possibility of interpreting multifragmentation data obtained from heavy-ion collisions at intermediate energies, by a new type of model: the DLNA (Dynamical Limited Nuclear Aggregation) is discussed. This model is connected to a more general class of models presenting Self-Organization Criticality (SOC). It is shown that the fragment size distributions exhibit a power-law dependence comparable to those obtained in second-order phase transition or percolation models. Fluctuations in term of scaled-factorial moments and cumulants are also studied: no signal of intermittency is seen. (K.A.)

  12. Fragmentation Main Model

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — The fragmentation model combines patch size and patch continuity with diversity of vegetation types per patch and rarity of vegetation types per patch. A patch was...

  13. Nuclear energy release from fragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Cheng [The Key Laboratory of Beam Technology and Material Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Souza, S.R. [Instituto de Física, Universidade Federal do Rio de Janeiro Cidade Universitária, Caixa Postal 68528, 21945-970 Rio de Janeiro (Brazil); Tsang, M.B. [The Key Laboratory of Beam Technology and Material Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); National Superconducting Cyclotron Laboratory and Physics and Astronomy Department, Michigan State University, East Lansing, MI 48824 (United States); Zhang, Feng-Shou, E-mail: fszhang@bnu.edu.cn [The Key Laboratory of Beam Technology and Material Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator of Lanzhou, Lanzhou 730000 (China)

    2016-08-15

    It is well known that binary fission occurs with positive energy gain. In this article we examine the energetics of splitting uranium and thorium isotopes into various numbers of fragments (from two to eight) with nearly equal size. We find that the energy released by splitting {sup 230,232}Th and {sup 235,238}U into three equal size fragments is largest. The statistical multifragmentation model (SMM) is applied to calculate the probability of different breakup channels for excited nuclei. By weighing the probability distributions of fragment multiplicity at different excitation energies, we find the peaks of energy release for {sup 230,232}Th and {sup 235,238}U are around 0.7–0.75 MeV/u at excitation energy between 1.2 and 2 MeV/u in the primary breakup process. Taking into account the secondary de-excitation processes of primary fragments with the GEMINI code, these energy peaks fall to about 0.45 MeV/u.

  14. Modelling the fragmentation mechanisms

    International Nuclear Information System (INIS)

    Bougault, R.; Durand, D.; Gulminelli, F.

    1998-01-01

    We have investigated the role of high amplitude collective motion in the nuclear fragmentation by using semi-classical macroscopic, as well as, microscopic simulations (BUU). These studies are motivated by the search of instabilities responsible for nuclear fragmentation. Two cases were examined: the bubble formation following the collective expansion of the compressed nucleus in case of very central reactions and, in the case of the semi-central collisions, the fast fission of the two partners issued from a binary reaction, in their corresponding Coulomb field. In the two cases the fragmentation channel is dominated by the inter-relation between the Coulomb and nuclear fields, and it is possible to obtain semi-quantitative predictions as functions of interaction parameters. The transport equations of BUU type predicts for central reactions formation of a high density transient state. Of much interest is the mechanism subsequent to de-excitation. It seems reasonable to conceive that the pressure stocked in the compressional mode manifests itself as a collective expansion of the system. As the pressure is a increasing function of the available energy one can conceive a variety of energy depending exit channels, starting from the fragmentation due the amplification of fluctuations interior to the spinodal zone up to the complete vaporization of the highly excited system. If the reached pressure is sufficiently high the reaction final state may preserve the memory of the entrance channel as a collective radial energy superimposed to the thermal disordered motion. Distributions of particles in the configuration space for both central and semi-central reactions for the Pb+Au system are presented. The rupture time is estimated to the order of 300 fm/c, and is strongly dependent on the initial temperature. The study of dependence of the rupture time on the interaction parameters is under way

  15. Dependence of simulated positron emitter yields in ion beam cancer therapy on modeling nuclear fragmentation

    DEFF Research Database (Denmark)

    Lühr, Armin; Priegnitz, Marlen; Fiedler, Fine

    2014-01-01

    In ion beam cancer therapy, range verification in patients using positron emission tomography (PET) requires the comparison of measured with simulated positron emitter yields. We found that (1) changes in modeling nuclear interactions strongly affected the positron emitter yields and that (2) Monte...... Carlo simulations with SHIELD-HIT10A reasonably matched the most abundant PET isotopes 11C and 15O. We observed an ion-energy (i.e., depth) dependence of the agreement between SHIELD-HIT10A and measurement. Improved modeling requires more accurate measurements of cross-section values....

  16. Scaling and critical behaviour in nuclear fragmentation

    International Nuclear Information System (INIS)

    Campi, X.

    1990-09-01

    These notes review recent results on nuclear fragmentation. An analysis of experimental data from exclusive experiments is made in the framework of modern theories of fragmentation of finite size objects. We discuss the existence of a critical regime of fragmentation and the relevance of scaling and finite size scaling

  17. Universality of projectile fragmentation model

    International Nuclear Information System (INIS)

    Chaudhuri, G.; Mallik, S.; Das Gupta, S.

    2012-01-01

    Presently projectile fragmentation reaction is an important area of research as it is used for the production of radioactive ion beams. In this work, the recently developed projectile fragmentation model with an universal temperature profile is used for studying the charge distributions of different projectile fragmentation reactions with different projectile target combinations at different incident energies. The model for projectile fragmentation consists of three stages: (i) abrasion, (ii) multifragmentation and (iii) evaporation

  18. Memory effects in nuclear fragmentation?

    International Nuclear Information System (INIS)

    Colonna, M.; Di Toro, M.; Guarnera, A.

    1994-01-01

    A general procedure to identify instability regions which lead to multifragmentation events is presented. The dominant mode at the instability point is determined from the knowledge of the mean properties (density and temperature) of the system at that point. For spinodal instabilities the dependence of fragment structures on the dynamical conditions is studied changing the beam energy and the considered equation of state. An important competition between two dynamical effects, expansion of the system and growth of fluctuations, is revealed. It is shown that in heavy-ion central collisions at medium energies memory effects of the configuration formed at the instability time could be observed in the final fragmentation pattern. Some hints towards a fully dynamical picture of fragmentation processes are finally suggested. ((orig.))

  19. Nuclear fragmentation with secondary decay in the context of conventional percolation model

    International Nuclear Information System (INIS)

    Santiago, A.J.

    1989-09-01

    Mass and energy spectra arising from proton-nucleus collisions at energies between 80 and 350 GeV were studied, using the conventional percolation model coupled with secondary decay of the clusters. (L.C.J.A.)

  20. A model for projectile fragmentation

    International Nuclear Information System (INIS)

    Chaudhuri, G; Mallik, S; Gupta, S Das

    2013-01-01

    A model for projectile fragmentation is developed whose origin can be traced back to the Bevalac era. The model positions itself between the phenomenological EPAX parametrization and transport models like 'Heavy Ion Phase Space Exploration' (HIPSE) model and antisymmetrised molecular dynamics (AMD) model. A very simple impact parameter dependence of input temperature is incorporated in the model which helps to analyze the more peripheral collisions. The model is applied to calculate the charge, isotopic distributions, average number of intermediate mass fragments and the average size of largest cluster at different Z bound of different projectile fragmentation reactions at different energies.

  1. Fast Biological Modeling for Voxel-based Heavy Ion Treatment Planning Using the Mechanistic Repair-Misrepair-Fixation Model and Nuclear Fragment Spectra

    Energy Technology Data Exchange (ETDEWEB)

    Kamp, Florian [Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut (United States); Department of Radiation Oncology, Technische Universität München, Klinikum Rechts der Isar, München (Germany); Physik-Department, Technische Universität München, Garching (Germany); Cabal, Gonzalo [Experimental Physics–Medical Physics, Ludwig Maximilians University Munich, Garching (Germany); Mairani, Andrea [Medical Physics Unit, Centro Nazionale Adroterapia Oncologica (CNAO), Pavia (Italy); Heidelberg Ion-Beam Therapy Center, Heidelberg (Germany); Parodi, Katia [Experimental Physics–Medical Physics, Ludwig Maximilians University Munich, Garching (Germany); Wilkens, Jan J. [Department of Radiation Oncology, Technische Universität München, Klinikum Rechts der Isar, München (Germany); Physik-Department, Technische Universität München, Garching (Germany); Carlson, David J., E-mail: david.j.carlson@yale.edu [Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut (United States)

    2015-11-01

    Purpose: The physical and biological differences between heavy ions and photons have not been fully exploited and could improve treatment outcomes. In carbon ion therapy, treatment planning must account for physical properties, such as the absorbed dose and nuclear fragmentation, and for differences in the relative biological effectiveness (RBE) of ions compared with photons. We combined the mechanistic repair-misrepair-fixation (RMF) model with Monte Carlo-generated fragmentation spectra for biological optimization of carbon ion treatment plans. Methods and Materials: Relative changes in double-strand break yields and radiosensitivity parameters with particle type and energy were determined using the independently benchmarked Monte Carlo damage simulation and the RMF model to estimate the RBE values for primary carbon ions and secondary fragments. Depth-dependent energy spectra were generated with the Monte Carlo code FLUKA for clinically relevant initial carbon ion energies. The predicted trends in RBE were compared with the published experimental data. Biological optimization for carbon ions was implemented in a 3-dimensional research treatment planning tool. Results: We compared the RBE and RBE-weighted dose (RWD) distributions of different carbon ion treatment scenarios with and without nuclear fragments. The inclusion of fragments in the simulations led to smaller RBE predictions. A validation of RMF against measured cell survival data reported in published studies showed reasonable agreement. We calculated and optimized the RWD distributions on patient data and compared the RMF predictions with those from other biological models. The RBE values in an astrocytoma tumor ranged from 2.2 to 4.9 (mean 2.8) for a RWD of 3 Gy(RBE) assuming (α/β){sub X} = 2 Gy. Conclusions: These studies provide new information to quantify and assess uncertainties in the clinically relevant RBE values for carbon ion therapy based on biophysical mechanisms. We present results from

  2. Fracture mechanics model of fragmentation

    International Nuclear Information System (INIS)

    Glenn, L.A.; Gommerstadt, B.Y.; Chudnovsky, A.

    1986-01-01

    A model of the fragmentation process is developed, based on the theory of linear elastic fracture mechanics, which predicts the average fragment size as a function of strain rate and material properties. This approach permits a unification of previous results, yielding Griffith's solution in the low-strain-rate limit and Grady's solution at high strain rates

  3. Dynamics and instabilities in nuclear fragmentation

    International Nuclear Information System (INIS)

    Colonna, M.; Guarnera, A.; Di Toro, M.; Latora, V.; Smerzi, A.; Catania Univ.

    1993-01-01

    A general procedure to identify instability regions which lead to multifragmentation events is presented. The method covers all possible sources of dynamical instabilities. Informations on the instability point, like the time when the nuclear system enters the critical region, the most unstable modes and the time constant of the exponential growing of the relative variances, are deduced without any numerical bias. Important memory effects in the fragmentation pattern are revealed. Some hints towards a fully dynamical picture of fragmentation processes are finally suggested. (author) 7 refs., 3 figs

  4. Nuclear fragmentation and the number of particle tracks in tissue

    International Nuclear Information System (INIS)

    Ponomarev, A. L.; Cucinotta, F. A.

    2006-01-01

    For high energy nuclei, the number of particle tracks per cell is modified by local nuclear reactions that occur, with large fluctuations expected for heavy ion tracks. Cells near the interaction site of a reaction will experience a much higher number of tracks than estimated by the average fluence. Two types of reaction products are possible and occur in coincidence; projectile fragments, which generally have smaller charge and similar velocity to that of the projectile, and target fragments, which are produced from the fragmentation of the nuclei of water atoms or other cellular constituents with low velocity. In order to understand the role of fragmentation in biological damage a new model of human tissue irradiated by heavy ions was developed. A box of the tissue is modelled with periodic boundary conditions imposed, which extrapolates the technique to macroscopic volumes of tissue. The cross sections for projectile and target fragmentation products are taken from the quantum multiple scattering fragmentation code previously developed at NASA Johnson Space Center. Statistics of fragmentation pathways occurring in a cell monolayer, as well as in a small volume of 10 x 10 x 10 cells are given. A discussion on approaches to extend the model to describe spatial distributions of inactivated or other cell damage types, as well as highly organised tissues of multiple cell types, is presented. (authors)

  5. The extended sum-rule model view of light and intermediate mass fragment emission in nuclear reactions at intermediate energies

    International Nuclear Information System (INIS)

    Brancus, I.M.; Rebel, H.; Wentz, J.; Corcalciuc, V.

    1989-11-01

    The original sum-rule model worked out by Wilczynski et al. and successfully used for a global description of complete and incomplete fusion reactions has been extended by a term accounting for dissipative processes of the dinuclear system on its way to fusion. When applying to light and heavy ion collisions with various targets at energies in the transitional region, the new term proves to be rather essential for reproducing the element distributions of the fragments emitted from rather asymmetric systems. (orig.) [de

  6. Dynamical effects in the Colomb expansion following nuclear fragmentation

    International Nuclear Information System (INIS)

    Chung, K.C.; Donangelo, R.J.; Schechter, H.

    1987-01-01

    The effects of the Colomb expansion on the fragment Kinetic energy spectrum for a fragmentating hot nuclear system is investigated. In particular, 12 C fragment spectra are calculated and compared with those predicted by the uniform expansion approximation. The results indicate that energy spectra of fragments are quite sensitive to the details of the Coulomb expansion treatment. (Author) [pt

  7. Toroidal and rotating bubble nuclei and the nuclear fragmentation

    International Nuclear Information System (INIS)

    Royer, G.; Fauchard, C.; Haddad, F.; Jouault, B.

    1997-01-01

    The energy of rotating bubble and toroidal nuclei predicted to be formed in central heavy ion collisions at intermediate energies is calculated within the generalized rotating liquid drop model. Previously, a one-parameter shape sequence has been defined to describe the path leading to pumpkin-like configurations and toroidal shapes. New analytical expressions for the shape dependent functions have been obtained. The potential barriers standing in these exotic deformation paths are compared with the three-dimensional and plane-fragmentation barriers. Metastable bubble-like minima only appear at very high angular momentum and above the three dimensional fragmentation barriers. In the toroidal deformation path of the heaviest systems exists a large potential pocket localized below the plane-fragmentation barriers. This might allow the temporary survival of heavy nuclear toroids before the final clusterization induced by the surface and proximity tension

  8. Nuclear Fragmentation in Clinical Heavy Ion Beams, Should We Worry?

    DEFF Research Database (Denmark)

    Bassler, Niels; Hansen, David Christoffer; Toftegaard, Jakob

    2012-01-01

    Particle therapy with fast ions is increasingly applied as a treatment option for localized inoperable tumour sites. One of the reasons for the increased complications of understanding heavy ion dosimetry and radiobiology stems from the mixed particle spectrum which occurs due to nuclear fragment......Particle therapy with fast ions is increasingly applied as a treatment option for localized inoperable tumour sites. One of the reasons for the increased complications of understanding heavy ion dosimetry and radiobiology stems from the mixed particle spectrum which occurs due to nuclear....... The concept of relative biological effectiveness (RBE) translates the physical dose to a biological effective dose which is iso-effective to photon radiation. Radiobiological models based on amorphous track structure such as the Local Effect Model, but also microdosimetry based models both rely on a full...... the sensitivity on the three fields mentioned above, including: turning off nuclear fragmentation entirely, changing all ineleastic cross sections +/- 20%, changing key parameters in the Fermi-Breakup (FB) model. Results show nuclear effects have their largest impact on the dose distribution. Stopping power...

  9. Imaging of Nuclear Fragmentation in Nuclear Track Emulsion Relativistic Nuclei

    International Nuclear Information System (INIS)

    Zarubina, I.G. JINR

    2011-01-01

    The method of nuclear track emulsion provides a uniquely complete observation of multiple fragment systems produced in dissociation of relativistic nuclei. The most valuable events of coherent dissociation of nuclei in narrow jets of light and the lightest nuclei with a net charge as in the initial nucleus, occurring without the production of fragments of the target nuclei and mesons (the so-called w hite s tars), comprise a few percent among the observed interactions. The data on this phenomenon are fragmented, and the interpretation is not offered. The dissociation degree of light O, Ne, Mg and Si, and as well as heavy Au, Pb and U nuclei may reach a complete destruction to light and the lightest nuclei and nucleons, resulting in cluster systems of an unprecedented complexity. Studies with relativistic neutron-deficient nuclei have special advantages due to more complete observations. An extensive collection of macro videos of such interactions in nuclear track emulsion gathered by the Becquerel collaboration is presented

  10. Revisiting the Lund Fragmentation Model

    International Nuclear Information System (INIS)

    Andersson, B.; Nilsson, A.

    1992-10-01

    We present a new method to implement the Lund Model fragmentation distributions for multi-gluon situations. The method of Sjoestrand, implemented in the well-known Monte Carlo simulation program JETSET, is robust and direct and according to his findings there are no observable differences between different ways to implement his scheme. His method can be described as a space-time method because the breakup proper time plays a major role. The method described in this paper is built on energy-momentum space methods. We make use of the χ-curve, which is defined directly from the energy momentum vectors of the partons. We have shown that the χ-curve describes the breakup properties and the final state energy momentum distributions in the mean. We present a method to find the variations around the χ-curve, which also implements the basic Lund Model fragmentation distributions (the area-law and the corresponding iterative cascade). We find differences when comparing the corresponding Monte Carlo implementation REVJET to the JETSET distributions inside the gluon jets. (au)

  11. Measuring the temperature of hot nuclear fragments

    International Nuclear Information System (INIS)

    Wuenschel, S.; Bonasera, A.; May, L.W.; Souliotis, G.A.; Tripathi, R.; Galanopoulos, S.; Kohley, Z.; Hagel, K.; Shetty, D.V.; Huseman, K.; Soisson, S.N.; Stein, B.C.; Yennello, S.J.

    2010-01-01

    A new thermometer based on fragment momentum fluctuations is presented. This thermometer exhibited residual contamination from the collective motion of the fragments along the beam axis. For this reason, the transverse direction has been explored. Additionally, a mass dependence was observed for this thermometer. This mass dependence may be the result of the Fermi momentum of nucleons or the different properties of the fragments (binding energy, spin, etc.) which might be more sensitive to different densities and temperatures of the exploding fragments. We expect some of these aspects to be smaller for protons (and/or neutrons); consequently, the proton transverse momentum fluctuations were used to investigate the temperature dependence of the source.

  12. Models of fragmentation with composite power laws

    Science.gov (United States)

    Tavassoli, Z.; Rodgers, G. J.

    1999-06-01

    Some models for binary fragmentation are introduced in which a time dependent transition size produces two regions of fragment sizes above and below the transition size. In the first model we assume a fixed rate of fragmentation for the largest fragment and two different rates of fragmentation in the two regions of sizes above and below the transition size. The model is solved exactly in the long time limit to reveal stable time-invariant solutions for the fragment size and mass distributions. These solutions exhibit composite power law behaviours; power laws with two different exponents for fragments in smaller and larger regions. A special case of the model with no fragmentation in the smaller size region is also examined. Another model is also introduced which have three regions of fragment sizes with different rates of fragmentation. The similarities between the stable distributions in our models and composite power law distributions from experimental work on shock fragmentation of long thin glass rods and thick clay plates are discussed.

  13. On the nuclear fragmentation mechanisms in nuclear collisions at intermediate and high energies

    International Nuclear Information System (INIS)

    Jipa, Al.; Besliu, C.; Felea, D.; Iliescu, B.; Ristea, O.; Ristea, M.; Calin, C.; Horbuniev, A.; Arsene, I.; Esanu, T.; Ochesanu, S.; Caramarcu, C.; Bordeianu, C.; Rosu, I.; Grossu, V.; Zgura, I.S.; Stan, E.; Mitu, C.; Potlog, M.; Cherciu, M.; Stefan, I.

    2004-01-01

    The nuclear fragmentation mechanisms can be discussed taking into account different scales. These scales are related to the fragment sizes. Taking into account the possible different fragmentation mechanisms of the nuclei at the same incident energy an analysis of the experimental results obtained in different experiments performed at the JINR Dubna (Russia), KEK Tsukuba (Japan), GSI Darmstadt (Germany) is done. Results on apparent temperatures, angular distributions, fragment momentum spectra, multiplicities of the intermediate mass fragments are used to analyse the competition between two possible nuclear fragmentation mechanisms, namely: a sudden fragmentation by explosive mechanisms, like shock waves, and a slow fragmentation by the 'fission' of the spectator regions, mainly, because of the interactions with the particles or fragments emitted from the participant region at transverse angles on the incident nucleus, in CMS.Some connections with chaos dynamics and fractal structure of the fragmentation patterns are included. (authors)

  14. Inclusive projectile fragmentation in the spectator model

    International Nuclear Information System (INIS)

    Hussein, M.S.; McVoy, K.W.

    1985-01-01

    Crazing-angle single spectra for projectile fragments from nuclear collisions exhibit a broad peak centered near the beam velocity, suggesting that these observed fragments play only a 'spectator' role in the reaction. Using only this spectator assumption (but not DWBA), it is found that a 'prior form' formulation of the reaction leads, via closure, to a -type estimate of the inclusive spectator spectrum, thus relating it to the reaction cross section for the 'participant' with the target. It is shown explicitly that this expression includes an improved multi-channel version of the Udagawa-Tamura formula for the 'breakup-fusion' or incomplete fusion cross section, and identifies it as the fluctuation part of the participant-target reaction cross section. A Glauber-type estimate of the distorted wave functions which enter clearly shows how the width of the peak in the spectator spectrum arises from the 'Fermi motion' within the projectile, as in the simple Serber model, but is modified by the 'overlap geometry' of the collision. (Author) [pt

  15. The identification method of the nuclear fragments in emulsions

    International Nuclear Information System (INIS)

    Jipa, Alexandru; Ocheseanu, Silvia; Caramarcu, Costin; Calin, Marius; Constantin, Florin; Stan, Emil

    2003-01-01

    The visualization detectors have been successfully used from the beginning of the study of the relativistic nuclear collisions. One of these detectors used in such experiments is the nuclear emulsion. To increase the speed of the passage from pictures to experimental data different methods and tools have been proposed during the time. For identifying the nuclear fragments obtained in the relativistic radioactive beams multiple layers of nuclear emulsions have been exposed in experiments performed at the Synchrophasotron from the JINR Dubna (BECQUEREL Collaboration). The nuclear fragments have been identified using PAVICOM scanning and measuring system. In the present work an identification method based on a real time image processing machine and a reconstruction algorithm based on special conformal transforms is proposed. The results obtained by this method are compared with those obtained using PAVICOM device. Because in this study only pictures have been used, not initial nuclear emulsions, some difficulties in the identification of the nuclear fragments with higher polar angles can appear. Generally, comparable results have been obtained. The authors thank Dr. Pavel Zarubin from JINR Dubna, Laboratory of High Energy Physics, and Dr. Maria Haiduc, Institute of Space Sciences Bucharest-Magurele, for the pictures of the nuclear emulsions exposed in these experiments. (authors)

  16. Shell effects at the touching point of nuclear fragments

    International Nuclear Information System (INIS)

    Poenaru, D.N.; Gherghescu, R.A.; Greiner, W.

    1999-01-01

    Shell correction energy of the fission fragments remains practically unchanged when the separation distance increases from the sum of their radii up to infinity. The variation with mass asymmetry of the total deformation energy at the touching point configuration shows the valleys corresponding to different decay modes, which are produced when the two proton and/or the two neutron numbers are magic or almost magic. We present a potential energy surface of the proton-rich α-emitter 106 Te, showing the α-decay valley, obtained with a phenomenological shell correction. We discuss the difficulties to produce such a valley on a potential energy surface of 236 Pu, calculated with the macroscopic-microscopic method, in which the nuclear level scheme is found within the two center shell model. The valleys mainly due to the double magic nuclei 100,132 Sn, 208 Pb, and other magic numbers, are illustrated by plotting the deformation energy at the touching point versus the proton number of the fragment, for the following parent nuclei: 106 Te, 116 Ce, 212 Po, 238 Th, 258 Fm and 264 Fm. For ternary fission the gain in energy of compact configurations as compared to aligned ones is analysed. (authors)

  17. High-energy nuclear reaction mechanisms - fission, fragmentation and spallation

    International Nuclear Information System (INIS)

    Kaufman, S.B.

    1987-01-01

    Measurements of the correlations in kinetic energy, mass, charge, and angle of coincident fragments formed in high-energy nuclear reactions have helped to characterize the processes of fission, fragmentation and spallation. For example, fission or fission-like two-body breakup mechanisms result in a strong angular correlation between two heavy fragments; in addition, the momentum transfer in the reaction can be deduced from the correlation. Another example is the multiplicity of light charged particles associated with a given heavy fragment, which is a measure of the violence of the collision, thus distinguishing between central and peripheral collisions. A summary of what has been learned about these processes from such studies will be given, along with some suggestions for further experiments

  18. Notes on scaling and critical behaviour in nuclear fragmentation

    International Nuclear Information System (INIS)

    Campi, X.; Krivine, H.

    1994-01-01

    The relevance of the concepts of scaling and critical behaviour in nuclear fragmentation is discussed. Experimental results are reviewed to check whether the signals of a percolation or liquid-gas phase transition manifest themselves in the data. (author). 45 refs., 10 figs., 2 tabs

  19. Dynamical and statistical bimodality in nuclear fragmentation

    Science.gov (United States)

    Mallik, S.; Chaudhuri, G.; Gulminelli, F.

    2018-02-01

    The origin of bimodal behavior in the residue distribution experimentally measured in heavy ion reactions is reexamined using Boltzmann-Uehling-Uhlenbeck simulations. We suggest that, depending on the incident energy and impact parameter of the reaction, both entrance channel and exit channel effects can be at the origin of the observed behavior. Specifically, fluctuations in the reaction mechanism induced by fluctuations in the collision rate, as well as thermal bimodality directly linked to the nuclear liquid-gas phase transition, are observed in our simulations. Both phenomenologies were previously proposed in the literature but presented as incompatible and contradictory interpretations of the experimental measurements. These results indicate that heavy ion collisions at intermediate energies can be viewed as a powerful tool to study both bifurcations induced by out-of-equilibrium critical phenomena, as well as finite-size precursors of thermal phase transitions.

  20. Investigation of Nuclear Fragmentation in Relativistic Heavy Ion Collisions Using Plastic - Nuclear - Track Detectors

    CERN Multimedia

    2002-01-01

    In this experiment CR39 plastic nuclear track detectors will be used which are sensitive to detect relativistic nuclear fragments with charges Z@$>$5. They will be analyzed using an automatic track measuring system which was developed at the University of Siegen.\\\\ \\\\ This allows to measure large quantities of tracks in these passive detectors and to perform high statistics experiments. We intend to measure cross sections for the production of nuclear fragments from heavy ion beams at the SPS. \\\\ \\\\ The energy independence of the cross sections predicted by the idea of limiting fragmentation will be tested at high energies. In exposures with different targets we plan to analyze the factorization of the fragmentation cross sections into a target depending factor and a factor depending on the beam particle and the fragment. The cross sections for one proton remov Coulomb dissociation. \\\\ \\\\ We plan to investigate Coulomb dissociation for different targets and different energies. Fragment and projectile charges ...

  1. Inclusive characteristics of the nuclear target fragmentation products induced by relativistic particles

    International Nuclear Information System (INIS)

    Bogatin, V.I.; Ganza, E.A.; Lozhkin, O.V.; Murin, Yu.A.; Oplavin, V.S.; Perfilov, N.A.; Yakovlev, Yu.P.

    1981-01-01

    An experimental investigation of inclusive characteristics of nuclei-target fragmentation is conducted for further development and test of physical value of the earlier suggested nuclear fragmentation model based on the connection of the fragmentation with fluctuations of the quasiparticle density in the two-component quantum liquid, an experimental investigation of the inclusive characteristics of the nuclei-target fragmentation is carried out. The processes of sup(3, 4, 6, 8)He and sup(6, 7, 8, 9, 11)Li fragment formation during the interaction of relativistic protons (Esub(p)=6.7 GeV) and deutrons (Esub(d)=3.1 GeV) with 112 Sn and 124 Sn isotopes are studied by the method of semiconductive ΔE-E detectors. Differential energy spectra of fragments and isotopic ratio of cross sections of their formation as well as data on the dependence of isotopic ratios of fragmentation cross sections on the energy of incident particles and on the fragment energy are obtained. Presented is a phenomenological model of fragmentation within the frames of which the obtained experimental data are analyzed [ru

  2. Nuclear fragmentation reactions in extended media studied with Geant4 toolkit

    Energy Technology Data Exchange (ETDEWEB)

    Pshenichnov, Igor, E-mail: pshenich@fias.uni-frankfurt.d [Frankfurt Institute for Advanced Studies, J.-W. Goethe University, 60438 Frankfurt am Main (Germany); Institute for Nuclear Research, Russian Academy of Science, 117312 Moscow (Russian Federation); Botvina, Alexander [Frankfurt Institute for Advanced Studies, J.-W. Goethe University, 60438 Frankfurt am Main (Germany); Institute for Nuclear Research, Russian Academy of Science, 117312 Moscow (Russian Federation); Mishustin, Igor [Frankfurt Institute for Advanced Studies, J.-W. Goethe University, 60438 Frankfurt am Main (Germany); Kurchatov Institute, Russian Research Center, 123182 Moscow (Russian Federation); Greiner, Walter [Frankfurt Institute for Advanced Studies, J.-W. Goethe University, 60438 Frankfurt am Main (Germany)

    2010-03-15

    It is well-known from numerous experiments that nuclear multifragmentation is a dominating mechanism for production of intermediate mass fragments in nucleus-nucleus collisions at energies above 100AMeV. In this paper we investigate the validity and performance of the Fermi break-up model and the statistical multifragmentation model implemented as parts of the Geant4 toolkit. We study the impact of violent nuclear disintegration reactions on the depth-dose profiles and yields of secondary fragments for beams of light and medium-weight nuclei propagating in extended media. Implications for ion-beam cancer therapy and shielding from cosmic radiation are discussed.

  3. Nuclear fragmentation reactions in extended media studied with Geant4 toolkit

    International Nuclear Information System (INIS)

    Pshenichnov, Igor; Botvina, Alexander; Mishustin, Igor; Greiner, Walter

    2010-01-01

    It is well-known from numerous experiments that nuclear multifragmentation is a dominating mechanism for production of intermediate mass fragments in nucleus-nucleus collisions at energies above 100AMeV. In this paper we investigate the validity and performance of the Fermi break-up model and the statistical multifragmentation model implemented as parts of the Geant4 toolkit. We study the impact of violent nuclear disintegration reactions on the depth-dose profiles and yields of secondary fragments for beams of light and medium-weight nuclei propagating in extended media. Implications for ion-beam cancer therapy and shielding from cosmic radiation are discussed.

  4. On the nuclear fragmentation mechanisms in nuclear collisions at intermediate and high energies

    International Nuclear Information System (INIS)

    Jipa, Al; Besliu, C.; Felea, D.

    2004-01-01

    The nuclear fragmentation mechanisms can be discussed by taking into account different scales related to the fragment sizes. Considering two fragmentation mechanisms of the nuclei at the same incident energy an analysis of the experimental results obtained was done. Goldhaber formula was improved by analyzing the discrepancies between data and theories concerning the projectile fragmentation. We implied that the projectile fragmentation process would be governed by the distribution of nucleon momenta in the projectile after the collision occurred. We used in our analysis protons from the 4 He + 7 Li at 4.5 GeV/c per nucleon incident momentum, as well as from 40 Ar + 12 C at 213 AMeV bombarding energy. We proved that in order to proceed in analyzing the projectile fragmentation process at intermediate and high energies one has to consider the dependence σ 0 on the apparent temperature of projectile nucleus after the collision took place. The generalized Bertsch correction for light projectile nuclei and fragments was used and the number of spatial correlations between identical nucleons having anticorrelated momenta was found. Thus we found apparent temperature values close to the separation energies of the considered fragments per number of fragments. The temperatures associated to kinetic energy spectra of the projectile fragments were calculated following two methods. The results from Bauer's method were compared with those obtained by fitting the kinetic energy distributions of the projectile fragments in the rest frame of the projectile with a Maxwellian curve. We also accomplished the comparison of the experimental results with similar events simulated with RQMD 2.4. All the results obtained suggested two nuclear fragmentation mechanisms: a sudden fragmentation by explosive mechanisms, like shock waves and a slow fragmentation by the 'fission' of the spectator regions, mainly because of the interactions with the particles or fragments emitted from the

  5. Coulomb effects in low-energy nuclear fragmentation

    Science.gov (United States)

    Wilson, John W.; Chun, Sang Y.; Badavi, Francis F.; John, Sarah

    1993-01-01

    Early versions of the Langley nuclear fragmentation code NUCFRAG (and a publicly released version called HZEFRG1) assumed straight-line trajectories throughout the interaction. As a consequence, NUCFRAG and HZEFRG1 give unrealistic cross sections for large mass removal from the projectile and target at low energies. A correction for the distortion of the trajectory by the nuclear Coulomb fields is used to derive fragmentation cross sections. A simple energy-loss term is applied to estimate the energy downshifts that greatly alter the Coulomb trajectory at low energy. The results, which are far more realistic than prior versions of the code, should provide the data base for future transport calculations. The systematic behavior of charge-removal cross sections compares favorably with results from low-energy experiments.

  6. Generation and Nuclear Translocation of Sumoylated Transmembrane Fragment of Cell Adhesion Molecule L1

    Science.gov (United States)

    Lutz, David; Wolters-Eisfeld, Gerrit; Joshi, Gunjan; Djogo, Nevena; Jakovcevski, Igor; Schachner, Melitta; Kleene, Ralf

    2012-01-01

    The functions of the cell adhesion molecule L1 in the developing and adult nervous system are triggered by homophilic and heterophilic interactions that stimulate signal transductions that activate cellular responses. Here, we show that stimulation of signaling by function-triggering L1 antibodies or L1-Fc leads to serine protease-dependent cleavage of full-length L1 at the plasma membrane and generation of a sumoylated transmembrane 70-kDa fragment comprising the intracellular and transmembrane domains and part of the extracellular domain. The 70-kDa transmembrane fragment is transported from the plasma membrane to a late endosomal compartment, released from endosomal membranes into the cytoplasm, and transferred from there into the nucleus by a pathway that depends on importin and chromatin-modifying protein 1. Mutation of the sumoylation site at Lys1172 or of the nuclear localization signal at Lys1147 abolished L1-stimulated generation or nuclear import of the 70-kDa fragment, respectively. Nuclear import of the 70-kDa fragment may activate cellular responses in parallel or in association with phosphorylation-dependent signaling pathways. Alterations in the levels of the 70-kDa fragment during development and in the adult after spinal cord injury or in a mouse model of Alzheimer disease suggest that this fragment is functionally implicated in development, regeneration, neurodegeneration, tumorigenesis, and possibly synaptic plasticity in the mature nervous system. PMID:22431726

  7. Complex nuclear-structure phenomena revealed from the nuclide production in fragmentation reactions

    International Nuclear Information System (INIS)

    Ricciardi, M.V.; Kelic, A.; Napolitani, P.; Schmidt, K.H.; Yordanov, O.; Ignatyuk, A.V.; Rejmund, F.

    2003-12-01

    Complex structural effects in the nuclide production from the projectile fragmentation of 1 A GeV 238 U nuclei in a titanium target are reported. The structure seems to be insensitive to the excitation energy induced in the reaction. This is in contrast to the prominent structural features found in nuclear fission and in transfer reactions, which gradually disappear with increasing excitation energy. Using the statistical model of nuclear reactions, relations to structural effects in nuclear binding and in the nuclear level density are demonstrated. (orig.)

  8. Fragmentation cross section measurements of iron projectiles using CR-39 plastic nuclear track detectors

    CERN Document Server

    Flesch, F; Huentrup, G; Roecher, H; Streibel, T; Winkel, E; Heinrich, W

    1999-01-01

    For long term space missions in which larger radiation doses are accumulated it is necessary to improve the precision of models predicting the space radiation environment. Different models are available to determine the flux of cosmic ray heavy ions behind shielding material. The accuracy of these predictions depends on the knowledge of the fragmentation cross sections, especially at energies of several hundred MeV/nucleon, where the particle flux is at a maximum and especially for those particles with high LET, i.e. iron nuclei. We have measured fragmentation cross sections of sup 5 sup 6 Fe projectiles at beam energies of 700 and 1700 A MeV using experimental set-ups with plastic nuclear track detectors. In this paper we describe the experimental technique to study the fragmentation reactions of sup 5 sup 6 Fe projectiles using CR-39 plastic nuclear track detectors. Results for different targets are presented.

  9. Modelling of the PELE fragmentation dynamics

    Science.gov (United States)

    Verreault, J.

    2014-05-01

    The Penetrator with Enhanced Lateral Effect (PELE) is a type of explosive-free projectile that undergoes radial fragmentation upon an impact with a target plate. This type of projectile is composed of a brittle cylindrical shell (the jacket) filled in its core with a material characterized with a large Poisson's ratio. Upon an impact with a target, the axial compression causes the filling to expand in the radial direction. However, due to the brittleness of the jacket material, very little radial deformation can occur which creates a radial stress between the two materials and a hoop stress in the jacket. Fragmentation of the jacket occurs if the hoop stress exceeds the material's ultimate stress. The PELE fragmentation dynamics is explored via Finite-Element Method (FEM) simulations using the Autodyn explicit dynamics hydrocode. The numerical results are compared with an analytical model based on wave interactions, as well as with the experimental investigation of Paulus and Schirm (1996). The comparison is based on the mechanical stress in the filling and the qualitative fragmentation of the jacket.

  10. Modelling of the PELE fragmentation dynamics

    International Nuclear Information System (INIS)

    Verreault, J

    2014-01-01

    The Penetrator with Enhanced Lateral Effect (PELE) is a type of explosive-free projectile that undergoes radial fragmentation upon an impact with a target plate. This type of projectile is composed of a brittle cylindrical shell (the jacket) filled in its core with a material characterized with a large Poisson's ratio. Upon an impact with a target, the axial compression causes the filling to expand in the radial direction. However, due to the brittleness of the jacket material, very little radial deformation can occur which creates a radial stress between the two materials and a hoop stress in the jacket. Fragmentation of the jacket occurs if the hoop stress exceeds the material's ultimate stress. The PELE fragmentation dynamics is explored via Finite-Element Method (FEM) simulations using the Autodyn explicit dynamics hydrocode. The numerical results are compared with an analytical model based on wave interactions, as well as with the experimental investigation of Paulus and Schirm (1996). The comparison is based on the mechanical stress in the filling and the qualitative fragmentation of the jacket.

  11. Plasma wake and nuclear forces on fragmented H+ transport

    International Nuclear Information System (INIS)

    Barriga-Carrasco, Manuel D; Deutsch, Claude

    2006-01-01

    The objective of the present work is to study the target electronic and nuclear interactions produced when a H + ion traverses classical plasma matter. Electronic interactions are treated by means of the dielectric formalism while nuclear interactions are dealt within the classical dispersion theory through a Monte Carlo computer code. The interactions through plasma electronic medium among close ions are called wake forces. We checked that these forces screen the Coulomb explosions of the two fragmented protons from the same H + ion decreasing their relative distance in the analysed cases. These forces align the interproton vector along the motion direction. They also tend the two-proton energy loss to the value of two isolated protons when at early times it is rather larger. Nevertheless most parts of these wake effects cannot be corroborated experimentally as they are masked by the projectile collisions with target nuclei in our numerical experiment. These collisions cancel the screening produced by the wake forces, increasing the interproton distance even faster than for bare Coulomb explosion. Also they misalign the interproton vector along the motion direction and contribute moderately to increase the energy loss of the fragmented H + ion. These nuclear collisions effects are more significant in reducing projectile velocity

  12. Improvements to a model of projectile fragmentation

    International Nuclear Information System (INIS)

    Mallik, S.; Chaudhuri, G.; Das Gupta, S.

    2011-01-01

    In a recent paper [Phys. Rev. C 83, 044612 (2011)] we proposed a model for calculating cross sections of various reaction products which arise from disintegration of projectile-like fragments resulting from heavy-ion collisions at intermediate or higher energy. The model has three parts: (1) abrasion, (2) disintegration of the hot abraded projectile-like fragment (PLF) into nucleons and primary composites using a model of equilibrium statistical mechanics, and (3) possible evaporation of hot primary composites. It was assumed that the PLF resulting from abrasion has one temperature T. Data suggested that, while just one value of T seemed adequate for most cross-section calculations, a single value failed when dealing with very peripheral collisions. We have now introduced a variable T=T(b) where b is the impact parameter of the collision. We argue that there are data which not only show that T must be a function of b but, in addition, also point to an approximate value of T for a given b. We propose a very simple formula: T(b)=D 0 +D 1 [A s (b)/A 0 ] where A s (b) is the mass of the abraded PLF and A 0 is the mass of the projectile; D 0 and D 1 are constants. Using this model we compute cross sections for several collisions and compare with data.

  13. Tests of spinning turbine fragment impact on casing models

    International Nuclear Information System (INIS)

    Wilbeck, J.S.

    1984-01-01

    Ten 1/11-scale model turbine missile impact tests were conducted at a Naval spin chamber test facility to assess turbine missile effects in nuclear plant design. The objective of the tests was to determine the effects of missile spin, blade crush, and target edge conditions on the impact of turbine disk fragments on the steel casing. The results were intended for use in making realistic estimates for the initial conditions of fragments that might escape the casing in the event of a disk burst in a nuclear plant. The burst of a modified gas turbine rotor in a high-speed spin chamber provided three missiles with the proper rotational and translational velocities of actual steam turbine fragments. Tests of bladed, spinning missiles were compared with previous tests of unbladed, nonspinning missiles. The total residual energy of the spinning missiles, as observed from high-speed photographs of disk burst, was the same as that of the nonspinning missiles launched in a piercing orientation. Tests with bladed missiles showed that for equal burst speeds, the residual energy of bladed missiles is less than that of unbladed missiles. Impacts of missiles near the edge of targets resulted in residual missile velocities greater than for central impact. (orig.)

  14. A semiclassical model for quark jet fragmentation

    International Nuclear Information System (INIS)

    Andersson, B.; Gustafson, G.; Peterson, C.

    1979-01-01

    A semiclassical model is presented for the way the energy of a fast quark is transformed into observable hadrons. It reproduces the features of 1+1 dimensional QED (the Schwinger model) concerning a flat rapidity distribution in the central region. It also reproduces results from phenomenological considerations, which, based upon scaling, predict that meson formation in the fragmentation region can be described by an iterative scheme, implying a set of coupled integral equations. In particular the model predicts that the probability to find a meson containing the leading quark is independent of the Feynman scaling variable z. The iterative structure corresponds to a Brownian motion with relevance both to the cofinement problems and to the distribution of mass in the quark jet. (orig.) [de

  15. Hypervelocity Impact Test Fragment Modeling: Modifications to the Fragment Rotation Analysis and Lightcurve Code

    Science.gov (United States)

    Gouge, Michael F.

    2011-01-01

    Hypervelocity impact tests on test satellites are performed by members of the orbital debris scientific community in order to understand and typify the on-orbit collision breakup process. By analysis of these test satellite fragments, the fragment size and mass distributions are derived and incorporated into various orbital debris models. These same fragments are currently being put to new use using emerging technologies. Digital models of these fragments are created using a laser scanner. A group of computer programs referred to as the Fragment Rotation Analysis and Lightcurve code uses these digital representations in a multitude of ways that describe, measure, and model on-orbit fragments and fragment behavior. The Dynamic Rotation subroutine generates all of the possible reflected intensities from a scanned fragment as if it were observed to rotate dynamically while in orbit about the Earth. This calls an additional subroutine that graphically displays the intensities and the resulting frequency of those intensities as a range of solar phase angles in a Probability Density Function plot. This document reports the additions and modifications to the subset of the Fragment Rotation Analysis and Lightcurve concerned with the Dynamic Rotation and Probability Density Function plotting subroutines.

  16. Nuclear fission fragment excitation of electronic transition laser media

    International Nuclear Information System (INIS)

    Lorents, D.C.; McCusker, M.V.; Rhodes, C.K.

    1976-01-01

    The properties of high energy electronic transition lasers excited by fission fragments are expanded. Specific characteristics of the media including density, excitation rates, wavelength, kinetics, fissile material, scale size, and medium uniformity are assessed. The use of epithermal neutrons, homogeneously mixed fissile material, and special high cross section nuclear isotopes to optimize coupling of the energy to the medium are shown to be important considerations maximizing the scale size, energy deposition, and medium uniformity. A performance limit point of approximately 1000 J/l in approximately 100 μs pulses is established for a large class of systems operating in the near ultraviolet and visible spectral regions. It is demonstrated that e-beam excitation can be used to simulate nuclear pumping conditions to facilitate the search for candidate media. Experimental data for the kinetics of a XeF* laser operating in Ar/Xe/F 2 /UF 6 mixtures are given. These reactor-pumped systems are suitable for scaling to volumes on the order of (meters) 3

  17. Fragmentation modeling of a resin bonded sand

    Science.gov (United States)

    Hilth, William; Ryckelynck, David

    2017-06-01

    Cemented sands exhibit a complex mechanical behavior that can lead to sophisticated models, with numerous parameters without real physical meaning. However, using a rather simple generalized critical state bonded soil model has proven to be a relevant compromise between an easy calibration and good results. The constitutive model formulation considers a non-associated elasto-plastic formulation within the critical state framework. The calibration procedure, using standard laboratory tests, is complemented by the study of an uniaxial compression test observed by tomography. Using finite elements simulations, this test is simulated considering a non-homogeneous 3D media. The tomography of compression sample gives access to 3D displacement fields by using image correlation techniques. Unfortunately these fields have missing experimental data because of the low resolution of correlations for low displacement magnitudes. We propose a recovery method that reconstructs 3D full displacement fields and 2D boundary displacement fields. These fields are mandatory for the calibration of the constitutive parameters by using 3D finite element simulations. The proposed recovery technique is based on a singular value decomposition of available experimental data. This calibration protocol enables an accurate prediction of the fragmentation of the specimen.

  18. Kaon fragmentation function from NJL-jet model

    International Nuclear Information System (INIS)

    Matevosyan, Hrayr H.; Thomas, Anthony W.; Bentz, Wolfgang

    2010-01-01

    The NJL-jet model provides a sound framework for calculating the fragmentation functions in an effective chiral quark theory, where the momentum and isospin sum rules are satisfied without the introduction of ad hoc parameters [1]. Earlier studies of the pion fragmentation functions using the Nambu-Jona-Lasinio (NJL) model within this framework showed good qualitative agreement with the empirical parameterizations. Here we extend the NJL-jet model by including the strange quark. The corrections to the pion fragmentation function and corresponding kaon fragmentation functions are calculated using the elementary quark to quark-meson fragmentation functions from NJL. The results for the kaon fragmentation function exhibit a qualitative agreement with the empirical parameterizations, while the unfavored strange quark fragmentation to pions is shown to be of the same order of magnitude as the unfavored light quark's. The results of these studies are expected to provide important guidance for the analysis of a large variety of semi-inclusive data.

  19. Study of Particle Production and Nuclear Fragmentation in Relativistic Heavy-Ion Collisions in Nuclear Emulsions

    CERN Multimedia

    2002-01-01

    % EMU11 \\\\ \\\\ We propose to use nuclear emulsions for the study of nuclear collisions of $^{207}$Pb, $^{197}$Au, and any other heavy-ion beams when they are available. We have, in the past, used $^{32}$S at 200A~GeV and $^{16}$O at 200A and 60A~GeV from CERN (Experiment EMU08) and at present the analysis is going on with $^{28}$Si beam from BNL at 14.5A~GeV. It will be important to compare the previous and the present investigations with the new $^{207}$Pb beam at 60-160A~GeV. We want to measure in nuclear emulsion, on an event by event basis, shower particle multiplicity, pseudorapidity density and density fluctuations of charged particles, charge multiplicity and angular distributions of projectile fragments, production and interaction cross-sections of heavily ionizing particles emitted from the target fragmentation. Special emphasis will be placed on the analysis of events produced in the central collisions which are selected on the basis of low energy fragments emitted from the target excitation. It woul...

  20. Improved description of the fragmentation of nuclear collective states

    International Nuclear Information System (INIS)

    Soloviev, V.G.

    1984-01-01

    A mathematical method is deveioped for a more accurate description of the fragmentation of one-phonon states forming giant resonances. The method consists in that the one-phonon states already fragmented are used in the two-phonon terms of wave functions. Strength functions are obtained for the exci excitation of collective charge-exchange states ano giant resonances in spherical nuclei

  1. About dynamic model of limiting fragmentation of heavy nuclei

    International Nuclear Information System (INIS)

    Kuchin, I.A.

    2001-01-01

    Full text: As is known, during last years defined progress in understanding of static aspect of a dynamic structure organization of massive nuclei was reached. The offered model of a 'crystalline' structure of the nucleus generalizes drop, shell and cluster models in a natural way. Now increased interest induces the phenomenon of limiting fragmentation of heavy nuclei. There is a hope, that clearing up the general regularities of a soft disintegration of the massive nuclei on nucleons, component it, in a broad range of high energies can give a valuable information about dynamics of origin of nuclear structures and nature of their qualitative difference from a quark system structure, i.e. from nucleons. The key for understanding the indicated phenomenon can be it's study in connection with other aspects of disintegration of the nuclei - Coulomb and diffraction dissociation, fission etc. The sequential analysis of all these a processes from a single point of view is possible only within the framework of results and methods of the dynamic system theory. The purpose of the present research is clearing up a possibility to understand the nature of limiting fragmentation as a consequence of development of dynamic instability in a system of the nuclei as a result of ions interaction at high energy. In the analysis we based on data of the phenomenological analysis of heavy ion interactions at ultra-relativistic energies obtained by many authors for a number of years. As a result we came to a conclusion about general stochastic nature of an investigated phenomenon. In it development the fragmentation passes three different stages. On the first there is a process of preparation of chaos at a quantum level in an outcome of a Coulomb dissociation of the approaching nuclei and isotopic recharge of their nucleons, carrying a random character. A dominant here - viscous dissociation of nuclei under an operation of Coulomb forces. (A two body initial state). Then the multiparticle

  2. Modelling of the PELE fragmentation dynamics

    NARCIS (Netherlands)

    Verreault, J.

    2014-01-01

    The Penetrator with Enhanced Lateral Effect (PELE) is a type of explosive-free projectile that undergoes radial fragmentation upon an impact with a target plate. This type of projectile is composed of a brittle cylindrical shell (the jacket) filled in its core with a material characterized with a

  3. Probabilistic Role Models and the Guarded Fragment

    DEFF Research Database (Denmark)

    Jaeger, Manfred

    2004-01-01

    We propose a uniform semantic framework for interpreting probabilistic concept subsumption and probabilistic role quantification through statistical sampling distributions. This general semantic principle serves as the foundation for the development of a probabilistic version of the guarded fragm...... fragment of first-order logic. A characterization of equivalence in that logic in terms of bisimulations is given....

  4. Probabilistic role models and the guarded fragment

    DEFF Research Database (Denmark)

    Jaeger, Manfred

    2006-01-01

    We propose a uniform semantic framework for interpreting probabilistic concept subsumption and probabilistic role quantification through statistical sampling distributions. This general semantic principle serves as the foundation for the development of a probabilistic version of the guarded fragm...... fragment of first-order logic. A characterization of equivalence in that logic in terms of bisimulations is given....

  5. Fragmentation model analysis of EN2700 fireball

    Czech Academy of Sciences Publication Activity Database

    Spurný, Pavel; Ceplecha, Zdeněk

    2005-01-01

    Roč. 95, 1-4 (2005), s. 477-487 ISSN 0167-9295. [Meteoroids 2004. London, Ontario, 16.08.2004-20.08.2004] R&D Projects: GA ČR GA205/03/1404 Institutional research plan: CEZ:AV0Z10030501 Keywords : ablation * fireball * fragmentation Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.975, year: 2005

  6. Effective progression of nuclear magnetic resonance-detected fragment hits.

    Science.gov (United States)

    Eaton, Hugh L; Wyss, Daniel F

    2011-01-01

    Fragment-based drug discovery (FBDD) has become increasingly popular over the last decade as an alternate lead generation tool to HTS approaches. Several compounds have now progressed into the clinic which originated from a fragment-based approach, demonstrating the utility of this emerging field. While fragment hit identification has become much more routine and may involve different screening approaches, the efficient progression of fragment hits into quality lead series may still present a major bottleneck for the broadly successful application of FBDD. In our laboratory, we have extensive experience in fragment-based NMR screening (SbN) and the subsequent iterative progression of fragment hits using structure-assisted chemistry. To maximize impact, we have applied this approach strategically to early- and high-priority targets, and those struggling for leads. Its application has yielded a clinical candidate for BACE1 and lead series in about one third of the SbN/FBDD projects. In this chapter, we will give an overview of our strategy and focus our discussion on NMR-based FBDD approaches. Copyright © 2011 Elsevier Inc. All rights reserved.

  7. Dose equivalent near the bone-soft tissue interface from nuclear fragments produced by high-energy protons

    Science.gov (United States)

    Shavers, M. R.; Poston, J. W.; Cucinotta, F. A.; Wilson, J. W.

    1996-01-01

    During manned space missions, high-energy nucleons of cosmic and solar origin collide with atomic nuclei of the human body and produce a broad linear energy transfer spectrum of secondary particles, called target fragments. These nuclear fragments are often more biologically harmful than the direct ionization of the incident nucleon. That these secondary particles increase tissue absorbed dose in regions adjacent to the bone-soft tissue interface was demonstrated in a previous publication. To assess radiological risks to tissue near the bone-soft tissue interface, a computer transport model for nuclear fragments produced by high energy nucleons was used in this study to calculate integral linear energy transfer spectra and dose equivalents resulting from nuclear collisions of 1-GeV protons transversing bone and red bone marrow. In terms of dose equivalent averaged over trabecular bone marrow, target fragments emitted from interactions in both tissues are predicted to be at least as important as the direct ionization of the primary protons-twice as important, if recently recommended radiation weighting factors and "worst-case" geometry are used. The use of conventional dosimetry (absorbed dose weighted by aa linear energy transfer-dependent quality factor) as an appropriate framework for predicting risk from low fluences of high-linear energy transfer target fragments is discussed.

  8. Quark fragmentation function and the nonlinear chiral quark model

    International Nuclear Information System (INIS)

    Zhu, Z.K.

    1993-01-01

    The scaling law of the fragmentation function has been proved in this paper. With that, we show that low-P T quark fragmentation function can be studied as a low energy physocs in the light-cone coordinate frame. We therefore use the nonlinear chiral quark model which is able to study the low energy physics under scale Λ CSB to study such a function. Meanwhile the formalism for studying the quark fragmentation function has been established. The nonlinear chiral quark model is quantized on the light-front. We then use old-fashioned perturbation theory to study the quark fragmentation function. Our first order result for such a function shows in agreement with the phenomenological model study of e + e - jet. The probability for u,d pair formation in the e + e - jet from our calculation is also in agreement with the phenomenological model results

  9. Evaluation of excitation energy and spin in fission fragments using the statistical model, and the FIPPS project

    International Nuclear Information System (INIS)

    Faust, H.; Koester, U.; Kessedjian, G.; Sage, C.; Chebboubi, A.

    2013-01-01

    We review the statistical model and its application for the process of nuclear fission. The expressions for excitation energy and spin distributions for the individual fission fragments are given. We will finally emphasize the importance of measuring prompt gamma decay to further test the statistical model in nuclear fission with the FIPPS project. (authors)

  10. Research on Splicing Method of Digital Relic Fragment Model

    Science.gov (United States)

    Yan, X.; Hu, Y.; Hou, M.

    2018-04-01

    In the course of archaeological excavation, a large number of pieces of cultural relics were unearthed, and the restoration of these fragments was done manually by traditional arts and crafts experts. In this process, cultural relics experts often try to splice the existing cultural relics, and then use adhesive to stick together the fragments of correct location, which will cause irreversible secondary damage to cultural relics. In order to minimize such damage, the surveyors combine 3D laser scanning with computer technology, and use the method of establishing digital cultural relics fragments model to make virtual splicing of cultural relics. The 3D software on the common market can basically achieve the model translation and rotation, using this two functions can be achieved manually splicing between models, mosaic records after the completion of the specific location of each piece of fragments, so as to effectively reduce the damage to the relics had tried splicing process.

  11. NJL-jet model for quark fragmentation functions

    International Nuclear Information System (INIS)

    Ito, T.; Bentz, W.; Cloeet, I. C.; Thomas, A. W.; Yazaki, K.

    2009-01-01

    A description of fragmentation functions which satisfy the momentum and isospin sum rules is presented in an effective quark theory. Concentrating on the pion fragmentation function, we first explain why the elementary (lowest order) fragmentation process q→qπ is completely inadequate to describe the empirical data, although the crossed process π→qq describes the quark distribution functions in the pion reasonably well. Taking into account cascadelike processes in a generalized jet-model approach, we then show that the momentum and isospin sum rules can be satisfied naturally, without the introduction of ad hoc parameters. We present results for the Nambu-Jona-Lasinio (NJL) model in the invariant mass regularization scheme and compare them with the empirical parametrizations. We argue that the NJL-jet model, developed herein, provides a useful framework with which to calculate the fragmentation functions in an effective chiral quark theory.

  12. Energy deposition at the bone-tissue interface from nuclear fragments produced by high-energy nucleons

    Science.gov (United States)

    Cucinotta, Francis A.; Hajnal, Ferenc; Wilson, John W.

    1990-01-01

    The transport of nuclear fragmentation recoils produced by high-energy nucleons in the region of the bone-tissue interface is considered. Results for the different flux and absorbed dose for recoils produced by 1 GeV protons are presented in a bidirectional transport model. The energy deposition in marrow cavities is seen to be enhanced by recoils produced in bone. Approximate analytic formulae for absorbed dose near the interface region are also presented for a simplified range-energy model.

  13. Shell closure at the touching point of nuclear fragments

    International Nuclear Information System (INIS)

    Poenaru, D.N.; Greiner, W.; Gherghescu, R.A.

    1998-01-01

    Shell correction energy of the fission fragments remains practically unchanged when the separation distance increases from the sum of their radii up to infinity. The variation with mass asymmetry of the total deformation energy at the touching point configuration shows the valleys corresponding to different decay modes, which are produced when the two proton and/or the two neutron numbers are magic or almost magic. We present a contour plot of the deformation energy of the proton-rich α-emitter 106 Te, showing for the first time the α-decay valley. Different valleys mainly due to the doubly magic nuclei 100,132 Sn, 208 Pb, and other magic numbers, are illustrated by plotting the deformation energy at the touching point versus the proton number of the fragment, for the following parent nuclei: 106 Te; 116 Ce; 212 Po; 228 Th; 258 Fm, and 264 Fm. (author). Letter-to-the-editor

  14. Nuclear structure via isomer tagging of fission fragments

    Science.gov (United States)

    Wu, C. Y.; Cline, D.; Simon, M. W.; Stoyer, M. A.

    1997-10-01

    The high efficiency for detecting high-fold γ rays by large Ge arrays makes it possible to study the detailed spectroscopy of many neutron-rich nuclei produced by fission. Major progress has been made using sealed spontaneous fission sources. Considerable improvement in selectivity is provided, with an open source, both by gating on isomers and by detection of both fission fragments in coincidence with the deexcitation γ rays (see the preceding contribution). The reconstructed kinematics allows a measure of fragment mass and the Doppler shift correction of γ rays. In a recent experiment, fission fragments were detected using half of the CHICO array and an annular PPAC in coincidence with deexcitation γ rays detected by the Rochester array of eight Compton-suppressed Ge detectors. The annular PPAC was located only 1.0" from a 3.7 μCi ^252Cf source for efficient isomer tagging. The correlation was studied between delayed, within a time window between 150 ns and 10 μs after a fission occurring, and prompt γ rays. Several prominent feeding patterns to isomers in the mass region around 100 and 130 are identified by such correlation study. Experimental details and results will be presented.

  15. Validation of ASTEC v2.0 corium jet fragmentation model using FARO experiments

    International Nuclear Information System (INIS)

    Hermsmeyer, S.; Pla, P.; Sangiorgi, M.

    2015-01-01

    Highlights: • Model validation base extended to six FARO experiments. • Focus on the calculation of the fragmented particle diameter. • Capability and limits of the ASTEC fragmentation model. • Sensitivity analysis of model outputs. - Abstract: ASTEC is an integral code for the prediction of Severe Accidents in Nuclear Power Plants. As such, it needs to cover all physical processes that could occur during accident progression, yet keeping its models simple enough for the ensemble to stay manageable and produce results within an acceptable time. The present paper is concerned with the validation of the Corium jet fragmentation model of ASTEC v2.0 rev3 by means of a selection of six experiments carried out within the FARO facility. The different conditions applied within these six experiments help to analyse the model behaviour in different situations and to expose model limits. In addition to comparing model outputs with experimental measurements, sensitivity analyses are applied to investigate the model. Results of the paper are (i) validation runs, accompanied by an identification of situations where the implemented fragmentation model does not match the experiments well, and discussion of results; (ii) its special attention to the models calculating the diameter of fragmented particles, the identification of a fault in one model implemented, and the discussion of simplification and ad hoc modification to improve the model fit; and, (iii) an investigation of the sensitivity of predictions towards inputs and parameters. In this way, the paper offers a thorough investigation of the merit and limitation of the fragmentation model used in ASTEC

  16. Break-up fragment topology in statistical multifragmentation models

    International Nuclear Information System (INIS)

    Raduta, Ad. R.

    2009-01-01

    Break-up fragmentation patterns together with kinetic and configurational energy fluctuations are investigated in the framework of a microcanonical model with fragment degrees of freedom over a broad excitation energy range. As long as fragment partitioning is approximately preserved, energy fluctuations are found to be rather insensitive to both the way in which the freeze-out volume is constrained and the trajectory followed by the system in the excitation-energy-freeze-out volume space. Due to hard-core repulsion, the freeze-out volume is found to be populated nonuniformly, its highly depleted core giving the source a bubble-like structure. The most probable localization of the largest fragments in the freeze-out volume may be inferred experimentally from their kinematic properties, largely dictated by Coulomb repulsion.

  17. Quark fragmentation functions in NJL-jet model

    Science.gov (United States)

    Bentz, Wolfgang; Matevosyan, Hrayr; Thomas, Anthony

    2014-09-01

    We report on our studies of quark fragmentation functions in the Nambu-Jona-Lasinio (NJL) - jet model. The results of Monte-Carlo simulations for the fragmentation functions to mesons and nucleons, as well as to pion and kaon pairs (dihadron fragmentation functions) are presented. The important role of intermediate vector meson resonances for those semi-inclusive deep inelastic production processes is emphasized. Our studies are very relevant for the extraction of transverse momentum dependent quark distribution functions from measured scattering cross sections. We report on our studies of quark fragmentation functions in the Nambu-Jona-Lasinio (NJL) - jet model. The results of Monte-Carlo simulations for the fragmentation functions to mesons and nucleons, as well as to pion and kaon pairs (dihadron fragmentation functions) are presented. The important role of intermediate vector meson resonances for those semi-inclusive deep inelastic production processes is emphasized. Our studies are very relevant for the extraction of transverse momentum dependent quark distribution functions from measured scattering cross sections. Supported by Grant in Aid for Scientific Research, Japanese Ministry of Education, Culture, Sports, Science and Technology, Project No. 20168769.

  18. Towards a population synthesis model of self-gravitating disc fragmentation and tidal downsizing II: the effect of fragment-fragment interactions

    Science.gov (United States)

    Forgan, D. H.; Hall, C.; Meru, F.; Rice, W. K. M.

    2018-03-01

    It is likely that most protostellar systems undergo a brief phase where the protostellar disc is self-gravitating. If these discs are prone to fragmentation, then they are able to rapidly form objects that are initially of several Jupiter masses and larger. The fate of these disc fragments (and the fate of planetary bodies formed afterwards via core accretion) depends sensitively not only on the fragment's interaction with the disc, but also with its neighbouring fragments. We return to and revise our population synthesis model of self-gravitating disc fragmentation and tidal downsizing. Amongst other improvements, the model now directly incorporates fragment-fragment interactions while the disc is still present. We find that fragment-fragment scattering dominates the orbital evolution, even when we enforce rapid migration and inefficient gap formation. Compared to our previous model, we see a small increase in the number of terrestrial-type objects being formed, although their survival under tidal evolution is at best unclear. We also see evidence for disrupted fragments with evolved grain populations - this is circumstantial evidence for the formation of planetesimal belts, a phenomenon not seen in runs where fragment-fragment interactions are ignored. In spite of intense dynamical evolution, our population is dominated by massive giant planets and brown dwarfs at large semimajor axis, which direct imaging surveys should, but only rarely, detect. Finally, disc fragmentation is shown to be an efficient manufacturer of free-floating planetary mass objects, and the typical multiplicity of systems formed via gravitational instability will be low.

  19. The role of the spectator assumption in models for projectile fragmentation

    International Nuclear Information System (INIS)

    Mc Voy, K.W.

    1984-01-01

    This review is restricted to direct-reaction models for the production of projectile fragments in nuclear collisions, at beam energies of 10 or more MeV/nucleon. Projectile fragments are normally identified as those which have near-beam velocities, and there seem to be two principal mechanisms for the production of these fast particles: 1. Direct breakup, 2. Sequential breakup. Of the two, the authors exclude from their discussion the ''sequential breakup'' process, in which the projectile is excited by the initial collision (either via inelastic scattering or transfer to unbound states) and then subsequently decays, outside the range of interaction

  20. Radioactive nuclear beam facilities based on projectile fragmentation

    International Nuclear Information System (INIS)

    Sherrill, B.M.

    1992-01-01

    The production of radioactive beams using direct separation techniques is discussed. The reaction mechanisms which can be used to produce radioactive beams with these techniques can be broadly divided into three groups, projectile fragmentation, nucleon transfer, and Coulomb disassociation. Radioactive nuclei produced in these ways have large forward momenta with relatively sharp angular distributions peaked near zero degrees which are suitable for collection with magnetic devices. Secondary beam intensities of up to a few percent of the primary beam intensity are possible, although depending on the production mechanism the beam emittance may be poor. Further beam purification can be achieved using atomic processes with profiled energy degraders. The features of the production reaction mechanism, separation techniques, and a review of world wide efforts are presented. The advantages and disadvantages of the method are presented, with discussion of techniques to overcome some of the disadvantages. (Author)

  1. Yields of nuclear fragments in the interactions of carbon nuclei with a beryllium target at a projectile energy of 0.6 GeV per nucleon

    Energy Technology Data Exchange (ETDEWEB)

    Abramov, B. M.; Alexeev, P. N.; Borodin, Yu. A.; Bulychjov, S. A. [National Research Center Kurchatov Institute, Institute for Theoretical and Experimental Physics (Russian Federation); Gudima, K. K. [Academy of Sciences of Moldova, Institute of Applied Physics (Moldova, Republic of); Dukhovskoy, I. A.; Krutenkova, A. P., E-mail: anna.krutenkova@itep.ru; Kulikov, V. V.; Martemianov, M. A.; Matsyuk, M. A. [National Research Center Kurchatov Institute, Institute for Theoretical and Experimental Physics (Russian Federation); Mashnik, S. G. [Los Alamos National Laboratory (United States); Turdakina, E. N.; Khanov, A. I. [National Research Center Kurchatov Institute, Institute for Theoretical and Experimental Physics (Russian Federation)

    2016-09-15

    The yields of long-lived nuclear fragments at an angle of 3.5° that originate fromthe fragmentation of carbon ions with an energy of T{sub 0} = 0.6 GeV per nucleon on a berylliumtarget were measured in the FRAGMexperiment at the ITEP TWA heavy-ion accelerator. The momentum spectra of these fragments cover both the fragmentation-maximum region and the cumulative region. The respective differential cross sections change by about five orders of magnitude. The momentum distributions of fragments in the laboratory frame and their kinetic-energy distributions in the rest frame of the fragmenting nucleus are used to test the predictions of four models of ion–ion interactions: BC, INCL++, LAQGSM03.03, and QMD.

  2. The Role of Nuclear Fragmentation in Particle Therapy and Space Radiation Protection.

    Science.gov (United States)

    Zeitlin, Cary; La Tessa, Chiara

    2016-01-01

    The transport of the so-called HZE particles (those having high charge, Z, and energy, E) through matter is crucially important both in space radiation protection and in the clinical setting where heavy ions are used for cancer treatment. HZE particles are usually considered those having Z > 1, though sometimes Z > 2 is meant. Transport physics is governed by two types of interactions, electromagnetic (ionization energy loss) and nuclear. Models of transport, such as those used in treatment planning and space mission planning must account for both effects in detail. The theory of electromagnetic interactions is well developed, but nucleus-nucleus collisions are so complex that no fundamental physical theory currently describes them. Instead, interaction models are generally anchored to experimental data, which in some areas are far from complete. The lack of fundamental physics knowledge introduces uncertainties in the calculations of exposures and their associated risks. These uncertainties are greatly compounded by the much larger uncertainties in biological response to HZE particles. In this article, we discuss the role of nucleus-nucleus interactions in heavy charged particle therapy and in deep space, where astronauts will receive a chronic low dose from galactic cosmic rays (GCRs) and potentially higher short-term doses from sporadic, unpredictable solar energetic particles (SEPs). GCRs include HZE particles; SEPs typically do not and we, therefore, exclude them from consideration in this article. Nucleus-nucleus collisions can result in the breakup of heavy ions into lighter ions. In space, this is generally beneficial because dose and dose equivalent are, on the whole, reduced in the process. The GCRs can be considered a radiation field with a significant high-LET component; when they pass through matter, the high-LET component is attenuated, at the cost of a slight increase in the low-LET component. Not only are the standard measures of risk

  3. Nuclear Fragmentation Induced by Relativistic Projectiles Studied in the 4$\\pi$ Configuration of Plastic Track Detectors

    CERN Multimedia

    2002-01-01

    % EMU19 \\\\ \\\\ The collisions of heavy ions at relativistic energies have been studied to explore a number of questions related with hot and dense nuclear matter in order to extend our knowledge of nuclear equation-of-state. There are other aspects of these interactions which are studied to expound the process of projectile and/or target disintegrations. The disintegrations in question could be simply binary fissions or more complex processes leading to spallation or complete fragmentation. These important aspects of nuclear reactions are prone to investigations with nuclear track detectors. \\\\ \\\\One of the comparatively new track detector materials, CR-39, is sensitive enough to record particles of Z~$\\geq$~6 with almost 100\\% efficiency up to highly relativistic energies. The wide angle acceptance and exclusive measurements possible with plastic track detectors offer an opportunity to use them in a variety of situations in which high energy charged fragments are produced. The off-line nature of measuring tra...

  4. Recombination plus fragmentation model at RHIC: elliptic flow

    Energy Technology Data Exchange (ETDEWEB)

    Nonaka, C [Department of Physics, Duke University, Durham, NC 27708 (United States); Fries, R J [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Mueller, B [Department of Physics, Duke University, Durham, NC 27708 (United States); Bass, S A [Department of Physics, Duke University, Durham, NC 27708 (United States); RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973 (United States); Asakawa, M [Department of Physics, Osaka University, Toyonaka 560-0043 (Japan)

    2005-04-01

    We discuss hadron production in relativistic heavy-ion collisions in the framework of the recombination and fragmentation model. We propose elliptic flow as a useful tool for exploring final interactions of resonances, the hadron structure of exotic particles and the phase structure of the reaction.

  5. High energy nuclear collisions in the few GeV/nucleon region: projectile and target fragmentation

    International Nuclear Information System (INIS)

    Schroeder, L.S.

    1980-06-01

    A general review of nucleon-nucleus and nucleus-nucleus collisions for incident energies <10 GeV/nucleon is presented. The division of these interactions into peripheral and central collisions is briefly discussed. Subjects treated include the following: target and projectile fragmentation systematics, production of exotic nuclear fragments, studies of multiparticle final states, total cross section measurements, results from an experiment that indicate the production of projectile fragments with an anomalously short reaction mean free path, high-energy particle production at backward angles beyond simple N-N kinematic limits, and recent results on backward particle emission in studies with the Berkeley streamer chamber. Both the particle and nuclear physics aspects that are present are considered. A brief discussion of future trends in this energy range ends the presentation. 65 references, 37 figures

  6. Fission and nuclear fragmentation of silver and bromine nuclei by photons of 1-6 GeV

    International Nuclear Information System (INIS)

    Pinheiro Filho, J.D.

    1983-01-01

    The studies of fission and fragmentation of silver and bromine nuclei by Bremsstrahlung photons of 1.6 GeV energy range are presented. The Il ford-KO nuclear emulsion submitted to Bremsstrahlung beams in Deutsches Elektronen Synchrotron (DESY) with total doses of 10'' equivalent photons, was used for nuclear fragment detection. The discrimination of fission and fragmentation events was done analysing angular distribution, range and angles between fragments. The results of fragment range distributions, angular distributions, distributions of angles between fragments, distributions of ratio between range, velocity distributions forward/backward ratio, cross sections of fission and fragmentation, nuclear fissionability and ternary fission frequency are presented and discussed. (M.C.K.)

  7. Analysis of multi-fragmentation reactions induced by relativistic heavy ions using the statistical multi-fragmentation model

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, T., E-mail: ogawa.tatsuhiko@jaea.go.jp [Research Group for Radiation Protection, Division of Environment and Radiation Sciences, Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency, Shirakata-Shirane, Tokai, Ibaraki 319-1195 (Japan); Sato, T.; Hashimoto, S. [Research Group for Radiation Protection, Division of Environment and Radiation Sciences, Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency, Shirakata-Shirane, Tokai, Ibaraki 319-1195 (Japan); Niita, K. [Research Organization for Information Science and Technology, Shirakata-shirane, Tokai, Ibaraki 319-1188 (Japan)

    2013-09-21

    The fragmentation cross-sections of relativistic energy nucleus–nucleus collisions were analyzed using the statistical multi-fragmentation model (SMM) incorporated with the Monte-Carlo radiation transport simulation code particle and heavy ion transport code system (PHITS). Comparison with the literature data showed that PHITS-SMM reproduces fragmentation cross-sections of heavy nuclei at relativistic energies better than the original PHITS by up to two orders of magnitude. It was also found that SMM does not degrade the neutron production cross-sections in heavy ion collisions or the fragmentation cross-sections of light nuclei, for which SMM has not been benchmarked. Therefore, SMM is a robust model that can supplement conventional nucleus–nucleus reaction models, enabling more accurate prediction of fragmentation cross-sections.

  8. Analysis of multi-fragmentation reactions induced by relativistic heavy ions using the statistical multi-fragmentation model

    International Nuclear Information System (INIS)

    Ogawa, T.; Sato, T.; Hashimoto, S.; Niita, K.

    2013-01-01

    The fragmentation cross-sections of relativistic energy nucleus–nucleus collisions were analyzed using the statistical multi-fragmentation model (SMM) incorporated with the Monte-Carlo radiation transport simulation code particle and heavy ion transport code system (PHITS). Comparison with the literature data showed that PHITS-SMM reproduces fragmentation cross-sections of heavy nuclei at relativistic energies better than the original PHITS by up to two orders of magnitude. It was also found that SMM does not degrade the neutron production cross-sections in heavy ion collisions or the fragmentation cross-sections of light nuclei, for which SMM has not been benchmarked. Therefore, SMM is a robust model that can supplement conventional nucleus–nucleus reaction models, enabling more accurate prediction of fragmentation cross-sections

  9. Recursive model for the fragmentation of polarized quarks

    Science.gov (United States)

    Kerbizi, A.; Artru, X.; Belghobsi, Z.; Bradamante, F.; Martin, A.

    2018-04-01

    We present a model for Monte Carlo simulation of the fragmentation of a polarized quark. The model is based on string dynamics and the 3P0 mechanism of quark pair creation at string breaking. The fragmentation is treated as a recursive process, where the splitting function of the subprocess q →h +q' depends on the spin density matrix of the quark q . The 3P0 mechanism is parametrized by a complex mass parameter μ , the imaginary part of which is responsible for single spin asymmetries. The model has been implemented in a Monte Carlo program to simulate jets made of pseudoscalar mesons. Results for single hadron and hadron pair transverse-spin asymmetries are found to be in agreement with experimental data from SIDIS and e+e- annihilation. The model predictions on the jet-handedness are also discussed.

  10. Production of photofission fragments and study of their nuclear structure by laser spectroscopy

    International Nuclear Information System (INIS)

    Gangrskij, Yu.P.; Zemlyanoj, S.G.; Karaivanov, D.V.; Marinova, K.P.; Markov, B.N.; Mel'nikova, L.M.; Myshinskij, G.V.; Penionzhkevich, Yu.Eh.; Zhemenik, V.I.

    2005-01-01

    The prospective nuclear structure investigations of the fission fragments by resonance laser spectroscopy methods are discussed. Research in this field is currently being carried out as part of the DRIBs project, which is under development at the Laboratory of Nuclear Reactions, JINR. The fission fragments under study are mainly very neutron-rich nuclei near the proton (Z=50) and neutron (N=50 and 82) closed shells, nuclei in the region of strong deformation (N>60 and N>90) and nuclei with high-spin isomeric states. Resonance laser spectroscopy is used successfully in the study of the structure of such nuclei. It allows one to determine a number of nuclear parameters (mean-square charge radius, magnetic dipole and electric quadrupole moments) and to make conclusions about the collective and single particle properties of the nuclei

  11. Double-arm time-of-flight mass-spectrometer of nuclear fragments

    International Nuclear Information System (INIS)

    Ajvazian, G.M.; Astabatyan, R.A.

    1995-01-01

    A double-arm time-of-flight spectrometer of nuclear fragments for the investigation of heavy nuclei photofission in the intermediate energy range is described. The calibration results and working characteristics of the spectrometer, obtained using 252 Cf as a source of spontaneous fission, are presented. A mass resolution of σ m ∼2-3 a.m.u. was obtained within the registered fragments mass range of 80-160 a.m.u. The spectrometer was tested in the experiment on the investigation of 238 U nuclei fission by Bremsstahlung photons with Eγ max=1.75 GeV

  12. Nuclear fragmentation in central collisions: Ni + Au from 32 to 90 A*MeV

    International Nuclear Information System (INIS)

    Bellaize, N.

    2000-01-01

    Heavy ion collisions are one of tools for studying nuclear system far away from its equilibrium state. This work concerns the most violent collisions in the Ni + Au system for incident energies ranging from 32 up to 90 AMeV. These events were detected with the multidetector INDRA and selected by the Principal Component Analysis (multidimensional analysis). This method classifies the events according their detection features and their degree of dissipation. We observed two deexcitation mechanisms: a fusion/fission - evaporation process and a multifragmentation process. Those two coexist from 32 to 52 AMeV whereas only one subsists at 90 AMeV. For those two mechanisms, an component was observed which seems to be linked to the initial phase of the reaction. The energy fluctuations of this component leads to variations in the energy deposit which determines the deexcitation of the system. The experimental multifragmentation data of the Ni + Au system (52 and 90 AMeV) were compared to the predictions of a statistical model and to the experimental data of the system Xe + Sn at 50 AMeV (also detected with INDRA). These comparisons show the lack of collective radial energy for fragments (Z≥10) in the Ni + Au system, and show that the degree of multifragmentation depends of the thermal excitation energy. Mean kinetic energies of particles and lights fragments (Z≥10) are larger in the Ni + Au system than the Xe + Sn system. This observation shows that these particles are more sensitive to the entrance channel for an asymmetric system than for a symmetric system (for the same number of nucleons). (author)

  13. Model of Structural Fragmentation Induced by High Pressure Torsion

    Czech Academy of Sciences Publication Activity Database

    Kratochvíl, J.; Kružík, Martin; Sedláček, R.

    2010-01-01

    Roč. 25, č. 1 (2010), s. 88-98 ISSN 1606-5131 Institutional research plan: CEZ:AV0Z10750506 Keywords : High-pressure torsion * intergranular glide * homogeneous deformation mode Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.649, year: 2010 http://library.utia.cas.cz/separaty/2010/MTR/kruzik-model of structural fragmentation induced by high pressure torsion.pdf

  14. Fission fragment charge and mass distributions in 239Pu(n ,f ) in the adiabatic nuclear energy density functional theory

    Science.gov (United States)

    Regnier, D.; Dubray, N.; Schunck, N.; Verrière, M.

    2016-05-01

    Background: Accurate knowledge of fission fragment yields is an essential ingredient of numerous applications ranging from the formation of elements in the r process to fuel cycle optimization for nuclear energy. The need for a predictive theory applicable where no data are available, together with the variety of potential applications, is an incentive to develop a fully microscopic approach to fission dynamics. Purpose: In this work, we calculate the pre-neutron emission charge and mass distributions of the fission fragments formed in the neutron-induced fission of 239Pu using a microscopic method based on nuclear density functional theory (DFT). Methods: Our theoretical framework is the nuclear energy density functional (EDF) method, where large-amplitude collective motion is treated adiabatically by using the time-dependent generator coordinate method (TDGCM) under the Gaussian overlap approximation (GOA). In practice, the TDGCM is implemented in two steps. First, a series of constrained EDF calculations map the configuration and potential-energy landscape of the fissioning system for a small set of collective variables (in this work, the axial quadrupole and octupole moments of the nucleus). Then, nuclear dynamics is modeled by propagating a collective wave packet on the potential-energy surface. Fission fragment distributions are extracted from the flux of the collective wave packet through the scission line. Results: We find that the main characteristics of the fission charge and mass distributions can be well reproduced by existing energy functionals even in two-dimensional collective spaces. Theory and experiment agree typically within two mass units for the position of the asymmetric peak. As expected, calculations are sensitive to the structure of the initial state and the prescription for the collective inertia. We emphasize that results are also sensitive to the continuity of the collective landscape near scission. Conclusions: Our analysis confirms

  15. Storage ion trap of an 'In-Flight Capture' type for precise mass measurement of radioactive nuclear reaction products and fission fragments

    International Nuclear Information System (INIS)

    Tarantin, N.I.

    2001-01-01

    Data on nuclear masses provide a basis for creating and testing various nuclear models. A tandem system of FLNR comprised of the U-400M cyclotron, the COMBAS magnetic separator and the mass-spectrometric ion trap of an 'in-flight capture' type is considered as a possible complex for producing of the short-lived nuclei in fragmentation reactions by heavy ions and for precise mass measurement of these nuclei. The plan of scientific and technical FLNR research includes a project DRIBs for producing beams of accelerated radioactive nuclear reaction products and photofission fragments. This project proposes also precise mass measurements of the fission fragment with the help of the ion trap. The in-flight entrance of the ions and their capture in the mass-spectrometric ion trap using the monochromatizing degrader, the static electric and magnetic fields and a new invention, a magnetic unidirectional transporting ventil, is considered

  16. DNA Length Modulates the Affinity of Fragments of Genomic DNA for the Nuclear Matrix In Vitro.

    Science.gov (United States)

    García-Vilchis, David; Aranda-Anzaldo, Armando

    2017-12-01

    Classical observations have shown that during the interphase the chromosomal DNA of metazoans is organized in supercoiled loops attached to a compartment known as the nuclear matrix (NM). Fragments of chromosomal DNA able to bind the isolated NM in vitro are known as matrix associated/attachment/addressed regions or MARs. No specific consensus sequence or motif has been found that may constitute a universal, defining feature of MARs. On the other hand, high-salt resistant DNA-NM interactions in situ define true DNA loop anchorage regions or LARs, that might correspond to a subset of the potential MARs but are not necessarily identical to MARs characterized in vitro, since there are several examples of MARs able to bind the NM in vitro but which are not actually bound to the NM in situ. In the present work we assayed the capacity of two LARs, as well as of shorter fragments within such LARs, for binding to the NM in vitro. Paradoxically the isolated (≈2 kb) LARs cannot bind to the NM in vitro while their shorter (≈300 pb) sub-fragments and other non-related but equally short DNA fragments, bind to the NM in a high-salt resistant fashion. Our results suggest that the ability of a given DNA fragment for binding to the NM in vitro primarily depends on the length of the fragment, suggesting that binding to the NM is modulated by the local topology of the DNA fragment in suspension that it is known to depend on the DNA length. J. Cell. Biochem. 118: 4487-4497, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  17. Percolation and nucleation approaches to nuclear fragmentation: criticality in very small systems

    Energy Technology Data Exchange (ETDEWEB)

    Santiago, A.J. [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Inst. de Fisica; Chung, K.C.

    1994-12-01

    Different criteria for criticality in very small systems are discussed in the context of percolation and nucleation approaches to nuclear fragmentation. It is shown that the probability threshold in percolation and interaction radius threshold in nucleation are very strongly dependent upon the adopted criterion. By using Monte Carlo method, similarities and dissimilarities between nucleation and percolation pictures are also pointed out. (author). 17 refs, 5 figs, 2 tabs.

  18. Percolation and nucleation approaches to nuclear fragmentation: criticality in very small systems

    International Nuclear Information System (INIS)

    Santiago, A.J.; Chung, K.C.

    1994-12-01

    Different criteria for criticality in very small systems are discussed in the context of percolation and nucleation approaches to nuclear fragmentation. It is shown that the probability threshold in percolation and interaction radius threshold in nucleation are very strongly dependent upon the adopted criterion. By using Monte Carlo method, similarities and dissimilarities between nucleation and percolation pictures are also pointed out. (author). 17 refs, 5 figs, 2 tabs

  19. The Role of Nuclear Fragmentation in Particle Therapy and Space Radiation Protection

    Directory of Open Access Journals (Sweden)

    Cary eZeitlin

    2016-03-01

    Full Text Available The transport of so-called HZE particles (those having high charge, Z, and energy, E through matter is crucially important both in space radiation protection and in the clinical setting where heavy ions are used for cancer treatment. Transport physics is governed by two types of interactions, electromagnetic (ionization energy loss and nuclear. Models of transport such as those used in treatment planning and space mission planning must account for both effects in detail. The theory of electromagnetic interactions is well developed, but nucleus-nucleus collisions are so complex that no fundamental physical theory currently describes them. Instead, interaction models are generally anchored to experimental data, which in some areas are far from complete. The lack of fundamental physics knowledge introduces uncertainties in the calculations of exposures and their associated risks. These uncertainties are greatly compounded by the much larger uncertainties in biological response to HZE particles. In this article, we discuss the role of nucleus-nucleus interactions in heavy charged particle therapy and in deep space, where astronauts will receive a chronic low dose from Galactic Cosmic Rays (GCRs and potentially higher short-term doses from sporadic, unpredictable Solar Energetic Particles (SEPs. GCRs include HZE particles; SEPs typically do not and we therefore exclude them from consideration in this article. Nucleus-nucleus collisions can result in the breakup of heavy ions into lighter ions. In space, this is generally beneficial because dose and dose equivalent are, on the whole, reduced in the process. The GCRs can be considered a radiation field with a significant high-LET component; when they pass through matter, the high-LET component is attenuated, at the cost of a slight increase in the low-LET component. Not only are the standard measures of risk reduced by fragmentation, but it can be argued that fragmentation also reduces the

  20. Model for self-polarization and motility of keratocyte fragments

    KAUST Repository

    Ziebert, F.; Swaminathan, S.; Aranson, I. S.

    2011-01-01

    Computational modelling of cell motility on substrates is a formidable challenge; regulatory pathways are intertwined and forces that influence cell motion are not fully quantified. Additional challenges arise from the need to describe a moving deformable cell boundary. Here, we present a simple mathematical model coupling cell shape dynamics, treated by the phase-field approach, to a vector field describing the mean orientation (polarization) of the actin filament network. The model successfully reproduces the primary phenomenology of cell motility: discontinuous onset of motion, diversity of cell shapes and shape oscillations. The results are in qualitative agreement with recent experiments on motility of keratocyte cells and cell fragments. The asymmetry of the shapes is captured to a large extent in this simple model, which may prove useful for the interpretation of experiments.

  1. Model for self-polarization and motility of keratocyte fragments

    KAUST Repository

    Ziebert, F.

    2011-10-19

    Computational modelling of cell motility on substrates is a formidable challenge; regulatory pathways are intertwined and forces that influence cell motion are not fully quantified. Additional challenges arise from the need to describe a moving deformable cell boundary. Here, we present a simple mathematical model coupling cell shape dynamics, treated by the phase-field approach, to a vector field describing the mean orientation (polarization) of the actin filament network. The model successfully reproduces the primary phenomenology of cell motility: discontinuous onset of motion, diversity of cell shapes and shape oscillations. The results are in qualitative agreement with recent experiments on motility of keratocyte cells and cell fragments. The asymmetry of the shapes is captured to a large extent in this simple model, which may prove useful for the interpretation of experiments.

  2. Nuclear targeting by fragmentation of the Potato spindle tuber viroid genome

    International Nuclear Information System (INIS)

    Abraitiene, Asta; Zhao Yan; Hammond, Rosemarie

    2008-01-01

    Transient expression of engineered reporter RNAs encoding an intron-containing green fluorescent protein (GFP) from a Potato virus X-based expression vector previously demonstrated the nuclear targeting capability of the 359 nucleotide Potato spindle tuber viroid (PSTVd) RNA genome. To further delimit the putative nuclear-targeting signal, PSTVd subgenomic fragments were embedded within the intron, and recombinant reporter RNAs were inoculated onto Nicotiana benthamiana plants. Appearance of green fluorescence in leaf tissue inoculated with PSTVd-fragment-containing constructs indicated shuttling of the RNA into the nucleus by fragments as short as 80 nucleotides in length. Plant-to-plant variation in the timing of intron removal and subsequent GFP fluorescence was observed; however, earliest and most abundant GFP expression was obtained with constructs containing the conserved hairpin I palindrome structure and embedded upper central conserved region. Our results suggest that this conserved sequence and/or the stem-loop structure it forms is sufficient for import of PSTVd into the nucleus

  3. Some comments on jet fragmentation models and sup(α)s determinations

    International Nuclear Information System (INIS)

    Sjoestrand, T.

    1984-03-01

    A number of interrelated topics on jet properties in e + e - annihilation is discussed. The need for different αsub(s) values in different fragmentation models is explained, with particular emphasis on the sensitivity to the choice of momentum conservation scheme in independent fragmentation models. Also other factors leading to a broad range of experimental αsub(s) values are discussed. Old and new methods to distinguish different fragmentation models are presented, with particular emphasis on gluon jet fragmentation properties. (orig.)

  4. Mathematical modeling of Myosin induced bistability of Lamellipodial fragments.

    Science.gov (United States)

    Hirsch, S; Manhart, A; Schmeiser, C

    2017-01-01

    For various cell types and for lamellipodial fragments on flat surfaces, externally induced and spontaneous transitions between symmetric nonmoving states and polarized migration have been observed. This behavior is indicative of bistability of the cytoskeleton dynamics. In this work, the Filament Based Lamellipodium Model (FBLM), a two-dimensional, anisotropic, two-phase continuum model for the dynamics of the actin filament network in lamellipodia, is extended by a new description of actin-myosin interaction. For appropriately chosen parameter values, the resulting model has bistable dynamics with stable states showing the qualitative features observed in experiments. This is demonstrated by numerical simulations and by an analysis of a strongly simplified version of the FBLM with rigid filaments and planar lamellipodia at the cell front and rear.

  5. Limiting fragmentation in a thermal model with flow

    Energy Technology Data Exchange (ETDEWEB)

    Kumar Tiwari, Swatantra; Sahoo, Raghunath [Indian Institute of Technology Indore, Discipline of Physics, School of Basic Sciences, Simrol, Indore (India)

    2016-12-15

    The property of limiting fragmentation of various observables such as rapidity distributions (dN/dy), elliptic flow (v{sub 2}), average transverse momentum (left angle p{sub T} right angle) etc. of charged particles is observed when they are plotted as a function of rapidity (y) shifted by the beam rapidity (y{sub beam}) for a wide range of energies from AGS to RHIC. Limiting fragmentation (LF) is a well-studied phenomenon as observed in various collision energies and colliding systems experimentally. It is very interesting to verify this phenomenon theoretically. We study such a phenomenon for pion rapidity spectra using our hydrodynamic-like model where the collective flow is incorporated in a thermal model in the longitudinal direction. Our findings advocate the observation of extended longitudinal scaling in the rapidity spectra of pions from AGS to lower RHIC energies, while it is observed to be violated at top RHIC and LHC energies. Prediction of LF hypothesis for Pb+Pb collisions at √(s{sub NN}) = 5.02 TeV is given. (orig.)

  6. Plasma wake and nuclear forces on fragmented H{sub {sup +}} transport

    Energy Technology Data Exchange (ETDEWEB)

    Barriga-Carrasco, Manuel D [E.T.S.I. Industriales, Universidad de Castilla-La Mancha, E-13071 Ciudad Real (Spain); Deutsch, Claude [Laboratoire de Physique des Gaz et des Plasmas, UMR-8578, Bat. 210, Universite Paris XI, F-91405 Orsay (France)

    2006-12-15

    The objective of the present work is to study the target electronic and nuclear interactions produced when a H{sub {sup +}} ion traverses classical plasma matter. Electronic interactions are treated by means of the dielectric formalism while nuclear interactions are dealt within the classical dispersion theory through a Monte Carlo computer code. The interactions through plasma electronic medium among close ions are called wake forces. We checked that these forces screen the Coulomb explosions of the two fragmented protons from the same H{sub {sup +}} ion decreasing their relative distance in the analysed cases. These forces align the interproton vector along the motion direction. They also tend the two-proton energy loss to the value of two isolated protons when at early times it is rather larger. Nevertheless most parts of these wake effects cannot be corroborated experimentally as they are masked by the projectile collisions with target nuclei in our numerical experiment. These collisions cancel the screening produced by the wake forces, increasing the interproton distance even faster than for bare Coulomb explosion. Also they misalign the interproton vector along the motion direction and contribute moderately to increase the energy loss of the fragmented H{sub {sup +}} ion. These nuclear collisions effects are more significant in reducing projectile velocity.

  7. Fuel fragmentation model advances using TEXAS-V

    Energy Technology Data Exchange (ETDEWEB)

    Corradini, M.L.; El-Beshbeeshy, M.; Nilsuwankowsit, S.; Tang, J. [Wisconsin Univ., Madison, WI (United States). Dept. of Nuclear Engineering and Engineering Physics

    1998-01-01

    Because an energetic fuel-coolant interaction may be a safety hazard, experiments are being conducted to investigate the fuel-coolant mixing/quenching process (FARO) as well as the energetics of vapor explosion propagation for high temperature fuel melt simulants (KROTOS, WFCI, ZrEX). In both types of experiments, the dynamic breakup of the fuel is one of the key aspects that must be fundamentally understood to better estimate the magnitude of the mixing/quenching process or the explosion energetics. To aid our understanding the TEXAS fuel-coolant interaction computer model has been developed and is being used to analyze these experiments. Recently, the models for dynamic fuel fragmentation during the mixing and explosion phases of the FCI have been improved by further insights into these processes. The purpose of this paper is to describe these enhancements and to demonstrate their improvements by analysis of particular JRC FCI data. (author)

  8. Study of stochastic approaches of the n-bodies problem: application to the nuclear fragmentation

    International Nuclear Information System (INIS)

    Guarnera, A.

    1996-01-01

    In the last decade nuclear physics research has found, with the observation of phenomena such as multifragmentation or vaporization, the possibility to get a deeper insight into the nuclear matter phase diagram. For example, a spinodal decomposition scenario has been proposed to explain the multifragmentation: because of the initial compression, the system may enter a region, the spinodal zone, in which the nuclear matter is no longer stable, and so any fluctuation leads to the formation of fragments. This thesis deals with spinodal decomposition within the theoretical framework of stochastic mean filed approaches, in which the one-body density function may experience a stochastic evolution. We have shown that these approaches are able to describe phenomena, such as first order phase transitions, in which fluctuations and many-body correlations plan an important role. In the framework of stochastic mean-filed approaches we have shown that the fragment production by spinodal decomposition is characterized by typical time scales of the order of 100 fm/c and by typical size scales around the Neon mass. We have also shown that these features are robust and that they are not affected significantly by a possible expansion of the system or by the finite size of nuclei. We have proposed as a signature of the spinodal decomposition some typical partition of the largest fragments. The study and the comparison with experimental data, performed for the reactions Xe + Cu at 45 MeV/A and Xe + Sn at 50 MeV/A, have shown a remarkable agreement. Moreover we would like to stress that the theory does not contain any adjustable parameter. These results seem to give a strong indication of the possibility to observe a spinodal decomposition of nuclei. (author)

  9. Non-statistical fluctuations in fragmentation of target nuclei in high energy nuclear interactions

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Dipak; Ghosh, Premomoy; Ghosh, Alokananda; Roy, Jaya [Jadavpur Univ., Calcutta (India)

    1994-07-01

    Analysis of target fragmented ''black'' particles in nuclear emulsion from high energy relativistic interactions initiated by [sup 16]O at 2.1 GeV/nucleon and [sup 12]C and [sup 24]Mg at 4.5 GeV/nucleon reveal the existence of non-statistical fluctuations in the azimuthal plane of interaction. The asymmetry or the non-statistical fluctuations, while found to be independent of projectile mass or incident energy, are dependent on the excitation energy of the target nucleus. (Author).

  10. Non-statistical fluctuations in fragmentation of target nuclei in high energy nuclear interactions

    International Nuclear Information System (INIS)

    Ghosh, Dipak; Ghosh, Premomoy; Ghosh, Alokananda; Roy, Jaya

    1994-01-01

    Analysis of target fragmented ''black'' particles in nuclear emulsion from high energy relativistic interactions initiated by 16 O at 2.1 GeV/nucleon and 12 C and 24 Mg at 4.5 GeV/nucleon reveal the existence of non-statistical fluctuations in the azimuthal plane of interaction. The asymmetry or the non-statistical fluctuations, while found to be independent of projectile mass or incident energy, are dependent on the excitation energy of the target nucleus. (Author)

  11. A multiple sampling time projection ionization chamber for nuclear fragment tracking and charge measurement

    International Nuclear Information System (INIS)

    Bauer, G.; Bieser, F.; Brady, F.P.; Chance, J.C.; Christie, W.F.; Gilkes, M.; Lindenstruth, V.; Lynen, U.; Mueller, W.F.J.; Romero, J.L.; Sann, H.; Tull, C.E.; Warren, P.

    1997-01-01

    A detector has been developed for the tracking and charge measurement of the projectile fragment nuclei produced in relativistic nuclear collisions. This device, MUSIC II, is a second generation Multiple Sampling Ionization Chamber (MUSIC), and employs the principles of ionization and time projection chambers. It provides unique charge determination for charges Z≥6, and excellent track position measurement. MUSIC II has been used most recently with the EOS (equation of state) TPC and other EOS collaboration detectors. Earlier it was used with other systems in experiments at the Heavy Ion Superconducting Spectrometer (HISS) facility at Lawrence Berkeley Laboratory and the ALADIN spectrometer at GSI. (orig.)

  12. Non-extensive statistical aspects of clustering and nuclear multi-fragmentation

    International Nuclear Information System (INIS)

    Calboreanu, A.

    2002-01-01

    Recent developments concerning an application of the non-extensive Tsalis statistics to describe clustering phenomena is briefly presented. Cluster formation is a common feature of a large number of physical phenomena encountered in molecular and nuclear physics, astrophysics, condensed matter and biophysics. Common to all these is the large number of degrees of freedom, thus justifying a statistical approach. However the conventional statistical mechanics paradigm seems to fail in dealing with clustering. Whether this is due to the prevalence of complex dynamical constrains, or it is a manifestation of new statistics is a subject of considerable interest, which was intensively debated during the last few years. Tsalis conjecture has proved extremely appealing due to its rather elegant and transparent basic arguments. We present here evidence for its adequacy for the study of a large class of physical phenomena related to cluster formation. An application to nuclear multi-fragmentation is presented. (author)

  13. Quantitative experimental modelling of fragmentation during explosive volcanism

    Science.gov (United States)

    Thordén Haug, Ø.; Galland, O.; Gisler, G.

    2012-04-01

    Phreatomagmatic eruptions results from the violent interaction between magma and an external source of water, such as ground water or a lake. This interaction causes fragmentation of the magma and/or the host rock, resulting in coarse-grained (lapilli) to very fine-grained (ash) material. The products of phreatomagmatic explosions are classically described by their fragment size distribution, which commonly follows power laws of exponent D. Such descriptive approach, however, considers the final products only and do not provide information on the dynamics of fragmentation. The aim of this contribution is thus to address the following fundamental questions. What are the physics that govern fragmentation processes? How fragmentation occurs through time? What are the mechanisms that produce power law fragment size distributions? And what are the scaling laws that control the exponent D? To address these questions, we performed a quantitative experimental study. The setup consists of a Hele-Shaw cell filled with a layer of cohesive silica flour, at the base of which a pulse of pressurized air is injected, leading to fragmentation of the layer of flour. The fragmentation process is monitored through time using a high-speed camera. By varying systematically the air pressure (P) and the thickness of the flour layer (h) we observed two morphologies of fragmentation: "lift off" where the silica flour above the injection inlet is ejected upwards, and "channeling" where the air pierces through the layer along sub-vertical conduit. By building a phase diagram, we show that the morphology is controlled by P/dgh, where d is the density of the flour and g is the gravitational acceleration. To quantify the fragmentation process, we developed a Matlab image analysis program, which calculates the number and sizes of the fragments, and so the fragment size distribution, during the experiments. The fragment size distributions are in general described by power law distributions of

  14. Calculating kaon fragmentation functions from the Nambu-Jona-Lasinio jet model

    International Nuclear Information System (INIS)

    Matevosyan, Hrayr H.; Thomas, Anthony W.; Bentz, Wolfgang

    2011-01-01

    The Nambu-Jona-Lasinio (NJL)-jet model provides a sound framework for calculating the fragmentation functions in an effective chiral quark theory, where the momentum and isospin sum rules are satisfied without the introduction of ad hoc parameters. Earlier studies of the pion fragmentation functions using the NJL model within this framework showed qualitative agreement with the empirical parametrizations. Here we extend the NJL-jet model by including the strange quark. The corrections to the pion fragmentation functions and corresponding kaon fragmentation functions are calculated using the elementary quark to quark-meson fragmentation functions from NJL. The results for the kaon fragmentation functions exhibit a qualitative agreement with the empirical parametrizations, while the unfavored strange quark fragmentation to pions is shown to be of the same order of magnitude as the unfavored light quark. The results of these studies are expected to provide important guidance for the analysis of a large variety of semi-inclusive data.

  15. Fragmentation of polarized 23Na on 208Pb and the random-walk model

    International Nuclear Information System (INIS)

    Clarke, N.M.; Karban, O.; Blyth, C.O.; Choi, H.D.; Hall, S.J.; Roman, S.; Tungate, G.; Cole, A.J.; Davis, N.J.; Shotter, A.C.; Connell, K.A.

    1993-01-01

    Inclusive measurements are presented for the differential cross sections and tensor analyzing powers ( TT 20 and T 20 ) of ions produced by the fragmentation of a beam of polarized 23 Na incident on a 208 Pb target at an energy of 195.5 MeV (8.5 MeV/nucleon). The data are discussed in terms of a simple ''shape-effect'' model, and compared to the predictions of the nuclear random-walk model which has been extended to the calculation of aligned, deformed projectiles. This model reproduces the principal features of the differential cross sections and the trends as a function of mass loss, but gives poorer agreement for the analyzing powers

  16. Experimental modelling of fragmentation applied to volcanic explosions

    Science.gov (United States)

    Haug, Øystein Thordén; Galland, Olivier; Gisler, Galen R.

    2013-12-01

    Explosions during volcanic eruptions cause fragmentation of magma and host rock, resulting in fragments with sizes ranging from boulders to fine ash. The products can be described by fragment size distributions (FSD), which commonly follow power laws with exponent D. The processes that lead to power-law distributions and the physical parameters that control D remain unknown. We developed a quantitative experimental procedure to study the physics of the fragmentation process through time. The apparatus consists of a Hele-Shaw cell containing a layer of cohesive silica flour that is fragmented by a rapid injection of pressurized air. The evolving fragmentation of the flour is monitored with a high-speed camera, and the images are analysed to obtain the evolution of the number of fragments (N), their average size (A), and the FSD. Using the results from our image-analysis procedure, we find transient empirical laws for N, A and the exponent D of the power-law FSD as functions of the initial air pressure. We show that our experimental procedure is a promising tool for unravelling the complex physics of fragmentation during phreatomagmatic and phreatic eruptions.

  17. Modelling the negative effects of landscape fragmentation on habitat selection

    NARCIS (Netherlands)

    Langevelde, van F.

    2015-01-01

    Landscape fragmentation constrains movement of animals between habitat patches. Fragmentation may, therefore, limit the possibilities to explore and select the best habitat patches, and some animals may have to cope with low-quality patches due to these movement constraints. If so, these individuals

  18. Completion of autobuilt protein models using a database of protein fragments

    International Nuclear Information System (INIS)

    Cowtan, Kevin

    2012-01-01

    Two developments in the process of automated protein model building in the Buccaneer software are described: the use of a database of protein fragments in improving the model completeness and the assembly of disconnected chain fragments into complete molecules. Two developments in the process of automated protein model building in the Buccaneer software are presented. A general-purpose library for protein fragments of arbitrary size is described, with a highly optimized search method allowing the use of a larger database than in previous work. The problem of assembling an autobuilt model into complete chains is discussed. This involves the assembly of disconnected chain fragments into complete molecules and the use of the database of protein fragments in improving the model completeness. Assembly of fragments into molecules is a standard step in existing model-building software, but the methods have not received detailed discussion in the literature

  19. Jet fragmentation

    International Nuclear Information System (INIS)

    Saxon, D.H.

    1985-10-01

    The paper reviews studies on jet fragmentation. The subject is discussed under the topic headings: fragmentation models, charged particle multiplicity, bose-einstein correlations, identified hadrons in jets, heavy quark fragmentation, baryon production, gluon and quark jets compared, the string effect, and two successful models. (U.K.)

  20. An Enumerative Combinatorics Model for Fragmentation Patterns in RNA Sequencing Provides Insights into Nonuniformity of the Expected Fragment Starting-Point and Coverage Profile.

    Science.gov (United States)

    Prakash, Celine; Haeseler, Arndt Von

    2017-03-01

    RNA sequencing (RNA-seq) has emerged as the method of choice for measuring the expression of RNAs in a given cell population. In most RNA-seq technologies, sequencing the full length of RNA molecules requires fragmentation into smaller pieces. Unfortunately, the issue of nonuniform sequencing coverage across a genomic feature has been a concern in RNA-seq and is attributed to biases for certain fragments in RNA-seq library preparation and sequencing. To investigate the expected coverage obtained from fragmentation, we develop a simple fragmentation model that is independent of bias from the experimental method and is not specific to the transcript sequence. Essentially, we enumerate all configurations for maximal placement of a given fragment length, F, on transcript length, T, to represent every possible fragmentation pattern, from which we compute the expected coverage profile across a transcript. We extend this model to incorporate general empirical attributes such as read length, fragment length distribution, and number of molecules of the transcript. We further introduce the fragment starting-point, fragment coverage, and read coverage profiles. We find that the expected profiles are not uniform and that factors such as fragment length to transcript length ratio, read length to fragment length ratio, fragment length distribution, and number of molecules influence the variability of coverage across a transcript. Finally, we explore a potential application of the model where, with simulations, we show that it is possible to correctly estimate the transcript copy number for any transcript in the RNA-seq experiment.

  1. Hard processes and fragmentation in a unified model for interactions at ultra-relativistic energies; Les processus durs et la fragmentation dans un modele unifie pour les interactions aux energies ultra-relativistes

    Energy Technology Data Exchange (ETDEWEB)

    Drescher, H.J

    1999-06-11

    In this work we have developed hard processes and string fragmentation in the framework of interactions at relativistic energies. The hypothesis of the universality of high energy interactions means that many elements of heavy ion collisions can be studied and simulated in simpler nuclear reactions. In particular this hypothesis implies that the fragmentation observed in the reaction e{sup +}e{sup -} follows the same rules as in the collision of 2 lead ions. This work deals with 2 nuclear processes: the e{sup +}e{sup -} annihilation reaction and the deep inelastic diffusion. For the first process the string model has been developed to simulate fragmentation by adding an artificial breaking of string due to relativistic effects. A monte-Carlo method has been used to determine the points in a Minkowski space where this breaking occurs. For the second reaction, the theory of semi-hard pomerons is introduced in order to define elementary hadron-hadron interactions. The model of fragmentation proposed in this work can be applied to more complicated reactions such as proton-proton or ion-ion collisions.

  2. Detection of fission fragments using thick samples in contact with solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Lima, D.A. de; Martins, J.B.; Tavares, O.A.P.

    1987-01-01

    Whenever use is made of thick samples in contact with solid state nuclear track detectors for determining fission yields, one of the fundamental problems is the evaluation of the effective number of target nuclei which contributes to the fraction of the number of fission events that will be recorded. The evaluation of the effective number of target nuclei which contributes to recorded events is based on the effective thickness of the sample. A method for evaluating effective thickness of thick samples for binary fission modes, is presented. A cross section equation which takes into account all the necessary corrections due to fragment attenuation effects by a thick target for calculation induced fission yields, was obtained. (Author) [pt

  3. Nuclear Alignment in Projectile Fragmentation as a Tool for Moment Measurements

    International Nuclear Information System (INIS)

    Georgiev, G.; Matea, I.; Oliveira Santos, F. de; Lewitowicz, M.; Daugas, J.M.; Belier, G.; Goutte, H.; Meot, V.; Roig, O.; Hass, M.; Baby, L.T.; Goldring, G.; Astabatyan, R.; Lukyanov, S.; Penionzhkevich, Yu.E.; Balabanski, D.L.; Borremans, D.; Himpe, P.; Neyens, G.; Sawicka, M.

    2004-01-01

    The application of the Time Dependent Perturbed Angular Distribution (TDPAD) method to study isomeric states produced and oriented in projectile-fragmentation reactions provides the opportunity to perform nuclear-moment measurements in a wide range of neutron-rich nuclei, unaccessible by other means. An absolute necessity for the application of the TDPAD technique is a spin-aligned ensemble of nuclei. The preliminary results from a recent application of this method on 61mFe and 54mFe at GANIL, Caen, France showed that a significant increase of the amount of the observed alignment, compared to our previous measurement on 67mNi and 69mCu, can be obtained. Some experimental details, concerning the conservation of the reaction obtained alignment, are discussed

  4. Nuclear fragmentation energy and momentum transfer distributions in relativistic heavy-ion collisions

    Science.gov (United States)

    Khandelwal, Govind S.; Khan, Ferdous

    1989-01-01

    An optical model description of energy and momentum transfer in relativistic heavy-ion collisions, based upon composite particle multiple scattering theory, is presented. Transverse and longitudinal momentum transfers to the projectile are shown to arise from the real and absorptive part of the optical potential, respectively. Comparisons of fragment momentum distribution observables with experiments are made and trends outlined based on our knowledge of the underlying nucleon-nucleon interaction. Corrections to the above calculations are discussed. Finally, use of the model as a tool for estimating collision impact parameters is indicated.

  5. Singly and Doubly Charged Projectile Fragments in Nucleus-Emulsion Collisions at Dubna Energy in the Framework of the Multi-Source Model

    International Nuclear Information System (INIS)

    Er-Qin, Wang; Fu-Hu, Liu; Jian-Xin, Sun; Rahim, Magda A.; Fakhraddin, S.

    2011-01-01

    The multiplicity distributions of projectile fragments emitted in interactions of different nuclei with emulsion are studied by using a multi-source model. Our calculated results show that the projectile fragments can be described by the model and each source contributes an exponential distribution. As the weighted sum of the folding result of many exponential distributions, a multi-component Erlang distribution is used to describe the experimental data. The relationship between the height (or width) of the distribution and the mass of the incident projectile, as well as the dependence of projectile fragments on target groups, are investigated too. (nuclear physics)

  6. DNA fragmentation and nuclear phenotype in tendons exposed to low-intensity infrared laser

    Science.gov (United States)

    de Paoli, Flavia; Ramos Cerqueira, Larissa; Martins Ramos, Mayara; Campos, Vera M.; Ferreira-Machado, Samara C.; Geller, Mauro; de Souza da Fonseca, Adenilson

    2015-03-01

    Clinical protocols are recommended in device guidelines outlined for treating many diseases on empirical basis. However, effects of low-intensity infrared lasers at fluences used in clinical protocols on DNA are controversial. Excitation of endogenous chromophores in tissues and free radicals generation could be described as a consequence of laser used. DNA lesions induced by free radicals cause changes in DNA structure, chromatin organization, ploidy degrees and cell death. In this work, we investigated whether low-intensity infrared laser therapy could alter the fibroblasts nuclei characteristics and induce DNA fragmentation. Tendons of Wistar rats were exposed to low-intensity infrared laser (830 nm), at different fluences (1, 5 and 10 J/cm2), in continuous wave (power output of 10mW, power density of 79.6 mW/cm2). Different frequencies were analyzed for the higher fluence (10 J/cm2), at pulsed emission mode (2.5, 250 and 2500 Hz), with the laser source at surface of skin. Geometric, densitometric and textural parameters obtained for Feulgen-stained nuclei by image analysis were used to define nuclear phenotypes. Significant differences were observed on the nuclear phenotype of tendons after exposure to laser, as well as, high cell death percentages was observed for all fluences and frequencies analyzed here, exception 1 J/cm2 fluence. Our results indicate that low-intensity infrared laser can alter geometric, densitometric and textural parameters in tendon fibroblasts nuclei. Laser can also induce DNA fragmentation, chromatin lost and consequently cell death, using fluences, frequencies and emission modes took out from clinical protocols.

  7. Crystallization and preliminary X-ray crystallographic studies of transportin 1 in complex with nucleocytoplasmic shuttling and nuclear localization fragments

    International Nuclear Information System (INIS)

    Imasaki, Tsuyoshi; Shimizu, Toshiyuki; Hashimoto, Hiroshi; Hidaka, Yuji; Yamada, Michiyuki; Sato, Mamoru

    2006-01-01

    Transportin 1 was cocrystallized with nucleocytoplasmic shuttling fragments of JKTBP and hnRNP D and a nuclear localization fragment of TAP. X-ray diffraction data were collected using synchrotron radiation at SPring-8. Nucleocytoplasmic transport of proteins with molar masses of larger than 60 000 is mediated by transport receptors. The transport receptor transportin1 (Trn1) transports various kinds of RNA-binding proteins such as JKTBP, hnRNP D and TAP. Trn1 was successfully cocrystallized with nucleocytoplasmic shuttling fragments of JKTBP and hnRNP D and a nuclear localization fragment of TAP. The crystal of the Trn1–JKTBP fragment complex belongs to space group P2 1 2 1 2, with unit-cell parameters a = 131.5, b =171.5, c = 68.2 Å. The crystals of Trn1 in complex with hnRNP D and TAP fragments are orthorhombic, space group P2 1 2 1 2 1 , with unit-cell parameters a = 69.1, b = 119.1, c = 151.1 Å and a = 69.0, b = 119.1, c = 146.0 Å, respectively. The crystals diffracted to beyond 3.0, 3.2 and 2.4 Å resolution, respectively, using synchrotron radiation at SPring-8

  8. Model of fragmentation of limestone particles during thermal shock and calcination in fluidised beds

    Energy Technology Data Exchange (ETDEWEB)

    Saastamoinen, J.; Pikkarainen, T.; Tourunen, A.; Rasanen, M.; Jantti, T. [VTT Technical Research Center, Jyvaskyla (Finland)

    2008-11-15

    Fragmentation of limestone due to thermal shock and calcination in a fluidised bed was studied through experiments and modelling. The time for heating was estimated by model calculations and the time for calcination by measurements. Fragmentation due to thermal shock was carried out by experiments in a CO{sub 2} atmosphere in order to prevent the effect of calcination. It was found to be much less than fragmentation due to calcination. Average particle sizes before and after fragmentation are presented for several types of limestone. The effects of particle size and gas composition on the primary fragmentation were studied through experiments. Increasing the fluidisation velocity increased the tendency to fragment. The evolution of the particle size distribution (PSD) of limestone particles due to thermal shock and during calcination (or simultaneous calcination and sulphation) were calculated using a population balance model. Fragmentation due to thermal shock is treated as an instantaneous process. The fragmentation frequency during calcination is presented as exponentially decaying over time. In addition to the final PSD, this model also predicts the PSD during the calcination process. The fragmentation was practically found to end after 10 min. Furthermore. a population balance method to calculate the particle size distribution and amount of limestone in fluidised beds in dynamic and steady state, when feeding history is known, is presented.

  9. Production of nuclear fragments from the interactions of 24 GeV/c protons in a gold target

    CERN Document Server

    Herz, A J; O'Sullivan, D; Thompson, A

    1976-01-01

    Lexan polycarbonate track detectors have been used to determine the charge and energy spectra of nuclear fragments with Z>or=6 and with kinetic energies as low as approximately=1.0 MeV/nucleon emitted from a thin gold target bombarded with 24 GeV/c protons. (8 refs).

  10. Test of quark fragmentation in the quark-parton model framework

    International Nuclear Information System (INIS)

    Derrick, M.; Barish, S.J.; Barnes, V.E.

    1979-08-01

    The hadronic system produced in charged-current antineutrino interactions is used to study fragmentation of the d-quark. Some problems encountered in separating the current quark-fragments are discussed. The fragmentation function for the current quark is in good agreement with the expectations of the naive quark-parton model and, in particular, there is no evidence of either a Q 2 - or x/sub BJ/-dependence. 10 references

  11. Nuclear Checker Board Model

    Science.gov (United States)

    Lach, Theodore

    2017-01-01

    The Checkerboard model of the Nucleus has been in the public domain for over 20 years. Over those years it has been described by nuclear and particle physicists as; cute, ``the Bohr model of the nucleus'' and ``reminiscent of the Eightfold Way''. It has also been ridiculed as numerology, laughed at, and even worse. In 2000 the theory was taken to the next level by attempting to explain why the mass of the ``up'' and ``dn'' quarks were significantly heavier than the SM ``u'' and ``d'' quarks. This resulted in a paper published on arXiv.nucl-th/0008026 in 2000, predicting 5 generations of quarks, each quark and negative lepton particle related to each other by a simple geometric mean. The CBM predicts that the radii of the elementary particles are proportional to the cube root of their masses. This was realized Pythagorean musical intervals (octave, perfect 5th, perfect 4th plus two others). Therefore each generation can be explained by a simple right triangle and the height of the hypotenuse. Notice that the height of a right triangle breaks the hypotenuse into two line segments. The geometric mean of those two segments equals the length of the height of this characteristic triangle. Therefore the CBM theory now predicts that all the elementary particles mass are proportion to the cube of their radii. Therefore the mass density of all elementary particles (and perhaps black holes too) are a constant of nature.

  12. Modeling nuclear processes by Simulink

    Energy Technology Data Exchange (ETDEWEB)

    Rashid, Nahrul Khair Alang Md, E-mail: nahrul@iium.edu.my [Faculty of Engineering, International Islamic University Malaysia, Jalan Gombak, Selangor (Malaysia)

    2015-04-29

    Modelling and simulation are essential parts in the study of dynamic systems behaviours. In nuclear engineering, modelling and simulation are important to assess the expected results of an experiment before the actual experiment is conducted or in the design of nuclear facilities. In education, modelling can give insight into the dynamic of systems and processes. Most nuclear processes can be described by ordinary or partial differential equations. Efforts expended to solve the equations using analytical or numerical solutions consume time and distract attention from the objectives of modelling itself. This paper presents the use of Simulink, a MATLAB toolbox software that is widely used in control engineering, as a modelling platform for the study of nuclear processes including nuclear reactor behaviours. Starting from the describing equations, Simulink models for heat transfer, radionuclide decay process, delayed neutrons effect, reactor point kinetic equations with delayed neutron groups, and the effect of temperature feedback are used as examples.

  13. Modeling nuclear processes by Simulink

    International Nuclear Information System (INIS)

    Rashid, Nahrul Khair Alang Md

    2015-01-01

    Modelling and simulation are essential parts in the study of dynamic systems behaviours. In nuclear engineering, modelling and simulation are important to assess the expected results of an experiment before the actual experiment is conducted or in the design of nuclear facilities. In education, modelling can give insight into the dynamic of systems and processes. Most nuclear processes can be described by ordinary or partial differential equations. Efforts expended to solve the equations using analytical or numerical solutions consume time and distract attention from the objectives of modelling itself. This paper presents the use of Simulink, a MATLAB toolbox software that is widely used in control engineering, as a modelling platform for the study of nuclear processes including nuclear reactor behaviours. Starting from the describing equations, Simulink models for heat transfer, radionuclide decay process, delayed neutrons effect, reactor point kinetic equations with delayed neutron groups, and the effect of temperature feedback are used as examples

  14. Proton induced target fragmentation studies on solid state nuclear track detectors using Carbon radiators

    Science.gov (United States)

    Szabó, J.; Pálfalvi, J. K.; Strádi, A.; Bilski, P.; Swakoń, J.; Stolarczyk, L.

    2018-04-01

    One of the limiting factors of an astronaut's career is the dose received from space radiation. High energy protons, being the main components of the complex radiation field present on a spacecraft, give a significant contribution to the dose. To investigate the behavior of solid state nuclear track detectors (SSNTDs) if they are irradiated by such particles, SSNTD stacks containing carbon blocks were exposed to high energy proton beams (70, 100, 150 and 230 MeV) at the Proteus cyclotron, IFJ PAN -Krakow. The incident protons cannot be detected directly; however, tracks of secondary particles, recoils and fragments of the constituent atoms of the detector material and of the carbon radiator are formed. It was found that as the proton energy increases, the number of tracks induced in the PADC material by secondary particles decreases. From the measured geometrical parameters of the tracks the linear energy transfer (LET) spectrum and the dosimetric quantities were determined, applying appropriate calibration. In the LET spectra the LET range of the most important secondary particles could be identified and their abundance showed differences in the spectra if the detectors were short or long etched. The LET spectra obtained on the SSNTDs irradiated by protons were compared to LET spectra of detectors flown on the International Space Station (ISS): they were quite similar, resulting in a quality factor difference of only 5%. Thermoluminescent detectors (TLDs) were applied in each case to measure the dose from primary protons and other lower LET particles present in space. Comparing and analyzing the results of the TLD and SSNTD measurements, it was obtained that proton induced target fragments contributed to the total absorbed dose in 3.2% and to the dose equivalent in 14.2% in this particular space experiment.

  15. The influence of fragmentation models in the production of hadron ...

    Indian Academy of Sciences (India)

    The analysis of electron–positron annihilations to hadrons at high energies shows that apart from two-jet events, there are also signs of three-jet events which are interpreted according to the QCD, as a gluon radiated by a quark. In this paper, we investigate the fragmentation of quarks and gluons to hadron jets. We show ...

  16. Global nuclear material control model

    International Nuclear Information System (INIS)

    Dreicer, J.S.; Rutherford, D.A.

    1996-01-01

    The nuclear danger can be reduced by a system for global management, protection, control, and accounting as part of a disposition program for special nuclear materials. The development of an international fissile material management and control regime requires conceptual research supported by an analytical and modeling tool that treats the nuclear fuel cycle as a complete system. Such a tool must represent the fundamental data, information, and capabilities of the fuel cycle including an assessment of the global distribution of military and civilian fissile material inventories, a representation of the proliferation pertinent physical processes, and a framework supportive of national or international perspective. They have developed a prototype global nuclear material management and control systems analysis capability, the Global Nuclear Material Control (GNMC) model. The GNMC model establishes the framework for evaluating the global production, disposition, and safeguards and security requirements for fissile nuclear material

  17. Hierarchical material models for fragmentation modeling in NIF-ALE-AMR

    International Nuclear Information System (INIS)

    Fisher, A C; Masters, N D; Koniges, A E; Anderson, R W; Gunney, B T N; Wang, P; Becker, R; Dixit, P; Benson, D J

    2008-01-01

    Fragmentation is a fundamental process that naturally spans micro to macroscopic scales. Recent advances in algorithms, computer simulations, and hardware enable us to connect the continuum to microstructural regimes in a real simulation through a heterogeneous multiscale mathematical model. We apply this model to the problem of predicting how targets in the NIF chamber dismantle, so that optics and diagnostics can be protected from damage. The mechanics of the initial material fracture depend on the microscopic grain structure. In order to effectively simulate the fragmentation, this process must be modeled at the subgrain level with computationally expensive crystal plasticity models. However, there are not enough computational resources to model the entire NIF target at this microscopic scale. In order to accomplish these calculations, a hierarchical material model (HMM) is being developed. The HMM will allow fine-scale modeling of the initial fragmentation using computationally expensive crystal plasticity, while the elements at the mesoscale can use polycrystal models, and the macroscopic elements use analytical flow stress models. The HMM framework is built upon an adaptive mesh refinement (AMR) capability. We present progress in implementing the HMM in the NIF-ALE-AMR code. Additionally, we present test simulations relevant to NIF targets

  18. Hierarchical material models for fragmentation modeling in NIF-ALE-AMR

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, A C; Masters, N D; Koniges, A E; Anderson, R W; Gunney, B T N; Wang, P; Becker, R [Lawrence Livermore National Laboratory, PO Box 808, Livermore, CA 94551 (United States); Dixit, P; Benson, D J [University of California San Diego, 9500 Gilman Dr., La Jolla. CA 92093 (United States)], E-mail: fisher47@llnl.gov

    2008-05-15

    Fragmentation is a fundamental process that naturally spans micro to macroscopic scales. Recent advances in algorithms, computer simulations, and hardware enable us to connect the continuum to microstructural regimes in a real simulation through a heterogeneous multiscale mathematical model. We apply this model to the problem of predicting how targets in the NIF chamber dismantle, so that optics and diagnostics can be protected from damage. The mechanics of the initial material fracture depend on the microscopic grain structure. In order to effectively simulate the fragmentation, this process must be modeled at the subgrain level with computationally expensive crystal plasticity models. However, there are not enough computational resources to model the entire NIF target at this microscopic scale. In order to accomplish these calculations, a hierarchical material model (HMM) is being developed. The HMM will allow fine-scale modeling of the initial fragmentation using computationally expensive crystal plasticity, while the elements at the mesoscale can use polycrystal models, and the macroscopic elements use analytical flow stress models. The HMM framework is built upon an adaptive mesh refinement (AMR) capability. We present progress in implementing the HMM in the NIF-ALE-AMR code. Additionally, we present test simulations relevant to NIF targets.

  19. Fragmentation of relativistic nuclei

    International Nuclear Information System (INIS)

    Cork, B.

    1975-06-01

    Nuclei with energies of several GeV/n interact with hadrons and produce fragments that encompass the fields of nuclear physics, meson physics, and particle physics. Experimental results are now available to explore problems in nuclear physics such as the validity of the shell model to explain the momentum distribution of fragments, the contribution of giant dipole resonances to fragment production cross sections, the effective Coulomb barrier, and nuclear temperatures. A new approach to meson physics is possible by exploring the nucleon charge-exchange process. Particle physics problems are explored by measuring the energy and target dependence of isotope production cross sections, thus determining if limiting fragmentation and target factorization are valid, and measuring total cross sections to determine if the factorization relation, sigma/sub AB/ 2 = sigma/sub AA/ . sigma/sub BB/, is violated. Also, new experiments have been done to measure the angular distribution of fragments that could be explained as nuclear shock waves, and to explore for ultradense matter produced by very heavy ions incident on heavy atoms. (12 figures, 2 tables)

  20. New Development on Modelling Fluctuations and Fragmentation in Heavy-Ion Collisions

    Science.gov (United States)

    Lin, Hao; Danielewicz, Pawel

    2017-09-01

    During heavy-ion collisions (HIC), colliding nuclei form an excited composite system. Instabilities present in the system may deform the shape of the system exotically, leading to a break-up into fragments. Many experimental efforts have been devoted to the nuclear multifragmentation phenomenon, while traditional HIC models, lacking in proper treatment of fluctuations, fall short in explaining it. In view of this, we are developing a new model to implement realistic fluctuations into transport simulation. The new model is motivated by the Brownian motion description of colliding particles. The effects of two-body collisions are recast in one-body diffusion processes. Vastly different dynamical paths are sampled by solving Langevin equations in momentum space. It is the stochastic sampling of dynamical paths that leads to a wide spread of exit channels. In addition, the nucleon degree of freedom is used to enhance the fluctuations. The model has been tested in reactions such as 112Sn + 112Sn and 58Ni + 58Ni, where reasonable results are yielded. An exploratory comparison on the 112Sn + 112Sn reaction at 50 MeV/nucleon with two other models, the stochastic mean-field (SMF) and the antisymmetrized molecular dynamics (AMD) models, has also been conducted. Work supported by the NSF Grant No. PHY-1403906.

  1. Monte Carlo simulation as a tool to predict blasting fragmentation based on the Kuz Ram model

    Science.gov (United States)

    Morin, Mario A.; Ficarazzo, Francesco

    2006-04-01

    Rock fragmentation is considered the most important aspect of production blasting because of its direct effects on the costs of drilling and blasting and on the economics of the subsequent operations of loading, hauling and crushing. Over the past three decades, significant progress has been made in the development of new technologies for blasting applications. These technologies include increasingly sophisticated computer models for blast design and blast performance prediction. Rock fragmentation depends on many variables such as rock mass properties, site geology, in situ fracturing and blasting parameters and as such has no complete theoretical solution for its prediction. However, empirical models for the estimation of size distribution of rock fragments have been developed. In this study, a blast fragmentation Monte Carlo-based simulator, based on the Kuz-Ram fragmentation model, has been developed to predict the entire fragmentation size distribution, taking into account intact and joints rock properties, the type and properties of explosives and the drilling pattern. Results produced by this simulator were quite favorable when compared with real fragmentation data obtained from a blast quarry. It is anticipated that the use of Monte Carlo simulation will increase our understanding of the effects of rock mass and explosive properties on the rock fragmentation by blasting, as well as increase our confidence in these empirical models. This understanding will translate into improvements in blasting operations, its corresponding costs and the overall economics of open pit mines and rock quarries.

  2. Mobile Learning Model and Process Optimization in the Era of Fragmentation

    Science.gov (United States)

    Zhang, Shi-Jun; Yu, Gui-Hua

    2017-01-01

    In the context of mobile Internet, college students' leisure time has fragmentation characteristics to improve the value of time, it is of great practical significance to make full use of fragmentation time to study effectively. This research focuses on mobile learning model and its effect, firstly, qualitative research is used to construct the…

  3. Estimation of cross sections of hypotetical 8n0, 10He2, 13Li3 nuclei production in the framework of fast fragmentation model

    International Nuclear Information System (INIS)

    Lozhkin, O.V.; Oplavin, V.S.; Yakovlev, Yu.P.

    1983-01-01

    The possibilities of search for 8 n 0 , 10 He 2 , 13 Li 3 nuclides in the products of nuclear fragmentation under the action of high energy particles are analysed. Conclusions have been drawn that: available experimental data on determination of the upper boundary of a cross section of 8 n 0 fragments production exclude an existence of this nuclide in the form ''usual'' nuclear system; available experimental estimations of cross sections of 10 He and 13 Li production among fragmentation products are, for the present, insufficient to solve a problem of 13 Li nucleus existence in a bound state but testify on 10 He nucleus nuclear instability; serious model estimations of have functions and nuclide binding energy are necessary

  4. Uncertainties in Nuclear Proliferation Modeling

    International Nuclear Information System (INIS)

    Kim, Chul Min; Yim, Man-Sung; Park, Hyeon Seok

    2015-01-01

    There have been various efforts in the research community to understand the determinants of nuclear proliferation and develop quantitative tools to predict nuclear proliferation events. Such systematic approaches have shown the possibility to provide warning for the international community to prevent nuclear proliferation activities. However, there are still large debates for the robustness of the actual effect of determinants and projection results. Some studies have shown that several factors can cause uncertainties in previous quantitative nuclear proliferation modeling works. This paper analyzes the uncertainties in the past approaches and suggests future works in the view of proliferation history, analysis methods, and variable selection. The research community still lacks the knowledge for the source of uncertainty in current models. Fundamental problems in modeling will remain even other advanced modeling method is developed. Before starting to develop fancy model based on the time dependent proliferation determinants' hypothesis, using graph theory, etc., it is important to analyze the uncertainty of current model to solve the fundamental problems of nuclear proliferation modeling. The uncertainty from different proliferation history coding is small. Serious problems are from limited analysis methods and correlation among the variables. Problems in regression analysis and survival analysis cause huge uncertainties when using the same dataset, which decreases the robustness of the result. Inaccurate variables for nuclear proliferation also increase the uncertainty. To overcome these problems, further quantitative research should focus on analyzing the knowledge suggested on the qualitative nuclear proliferation studies

  5. Collins fragmentation function for pions and kaons in a spectator model

    Energy Technology Data Exchange (ETDEWEB)

    Bacchetta, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Gamberg, L.P. [Penn State Univ., Berks, PA (United States). Dept. of Physics; Goldstein, G.R. [Tufts Univ., Medford, MA (United States). Dept. of Physics and Astronomy; Mukherjee, A. [Indian Institute of Technology Bombay, Mumbai (India). Physics Dept.

    2007-07-15

    We calculate the Collins fragmentation function in the framework of a spectator model with pseudoscalar pion-quark coupling and a Gaussian form factor at the vertex. We determine the model parameters by fitting the unpolarized fragmentation function for pions and kaons. We show that the Collins function for the pions in this model is in reasonable agreement with recent parametrizations obtained by fits of the available data. In addition, we compute for the first time the Collins function for the kaons. (orig.)

  6. Charge distributions and correlations in fragmentation models for soft hadron collisions

    International Nuclear Information System (INIS)

    Wolf, E.A. de

    1984-01-01

    Data on charge distributions and charge correlations in pp and meson-proton interactions at PS and SPS energies are successfully compared with the Lund fragmentation model for low-psub(T) hadron collisions. It is argued that local conservation of quantum numbers and resonance production, as implemented in fragmentation models, are sufficient ingredients to explain most of the available experimental results at these energies. No necessity is found for dual-sheet contributions considered in DTU-based parton models. (orig.)

  7. Tests of models for inclusive production of energetic light fragments at intermediate energies

    International Nuclear Information System (INIS)

    Boal, D.H.; Green, R.E.L.; Korteling, R.G.; Soroushian, M.

    1980-09-01

    Several models of light fragment emission are confronted with data from electron and proton induced reactions. The data appear to favor a mechanism, called the snowball model here, in which there is a single collison of the projectile and a few collisions of the secondary nucleons which then form the observed fragment. The parameter of the model is determined by fitting new isotopically separated inclusive differential cross section data taken at TRIUMF. (auth)

  8. Controlled isotropic fission fragment sources on the base of nuclear-physical facilities

    International Nuclear Information System (INIS)

    Sevast'yanov, V.D.; Maslov, G.N.

    1995-01-01

    Isotropic fission fragment sources (IFFS) are developed on the base of a neutron generator and pulse fast reactor. IFFS permit to calibrate fission fragment detectors. The IFFS consist of radiators with 235 U. The radiators are placed in a thermal neutron field of the neutron generator or in the reactor core center. The fragment activity is controlled by indications of an α-particle counter or by indications of a monitor of energy release in the core. 14 refs.; 1 fig.; 1 tab

  9. Behind-armour Debris Modelling for High- velocity Fragment Impact (Part 2)

    National Research Council Canada - National Science Library

    Verolme, J

    1997-01-01

    This report presents the results of impact experiments and a parallel simulation modelling thereof, with the main objective to study the fragmentation properties of tungsten and steel projectiles at impact...

  10. Large Time Asymptotics for a Continuous Coagulation-Fragmentation Model with Degenerate Size-Dependent Diffusion

    KAUST Repository

    Desvillettes, Laurent; Fellner, Klemens

    2010-01-01

    We study a continuous coagulation-fragmentation model with constant kernels for reacting polymers (see [M. Aizenman and T. Bak, Comm. Math. Phys., 65 (1979), pp. 203-230]). The polymers are set to diffuse within a smooth bounded one

  11. A new statistical scission-point model fed with microscopic ingredients to predict fission fragments distributions

    International Nuclear Information System (INIS)

    Heinrich, S.

    2006-01-01

    Nucleus fission process is a very complex phenomenon and, even nowadays, no realistic models describing the overall process are available. The work presented here deals with a theoretical description of fission fragments distributions in mass, charge, energy and deformation. We have reconsidered and updated the B.D. Wilking Scission Point model. Our purpose was to test if this statistic model applied at the scission point and by introducing new results of modern microscopic calculations allows to describe quantitatively the fission fragments distributions. We calculate the surface energy available at the scission point as a function of the fragments deformations. This surface is obtained from a Hartree Fock Bogoliubov microscopic calculation which guarantee a realistic description of the potential dependence on the deformation for each fragment. The statistic balance is described by the level densities of the fragment. We have tried to avoid as much as possible the input of empirical parameters in the model. Our only parameter, the distance between each fragment at the scission point, is discussed by comparison with scission configuration obtained from full dynamical microscopic calculations. Also, the comparison between our results and experimental data is very satisfying and allow us to discuss the success and limitations of our approach. We finally proposed ideas to improve the model, in particular by applying dynamical corrections. (author)

  12. Nuclear models relevant to evaluation

    International Nuclear Information System (INIS)

    Arthur, E.D.; Chadwick, M.B.; Hale, G.M.; Young, P.G.

    1991-01-01

    The widespread use of nuclear models continues in the creation of data evaluations. The reasons include extension of data evaluations to higher energies, creation of data libraries for isotopic components of natural materials, and production of evaluations for radiative target species. In these cases, experimental data are often sparse or nonexistent. As this trend continues, the nuclear models employed in evaluation work move towards more microscopically-based theoretical methods, prompted in part by the availability of increasingly powerful computational resources. Advances in nuclear models applicable to evaluation will be reviewed. These include advances in optical model theory, microscopic and phenomenological state and level density theory, unified models that consistently describe both equilibrium and nonequilibrium reaction mechanism, and improved methodologies for calculation of prompt radiation from fission. 84 refs., 8 figs

  13. Monte Carlo simulations of hadronic fragmentation functions using the Nambu-Jona-Lasinio-jet model

    International Nuclear Information System (INIS)

    Matevosyan, Hrayr H.; Thomas, Anthony W.; Bentz, Wolfgang

    2011-01-01

    The recently developed Nambu-Jona-Lasinio--jet model is used as an effective chiral quark theory to calculate the quark fragmentation functions to pions, kaons, nucleons, and antinucleons. The effects of the vector mesons ρ, K * , and φ on the production of secondary pions and kaons are included. The fragmentation processes to nucleons and antinucleons are described by using the quark-diquark picture, which has been shown to give a reasonable description of quark distribution functions. We incorporate effects of next-to-leading order in the Q 2 evolution, and compare our results with the empirical fragmentation functions.

  14. Fragment-based {sup 13}C nuclear magnetic resonance chemical shift predictions in molecular crystals: An alternative to planewave methods

    Energy Technology Data Exchange (ETDEWEB)

    Hartman, Joshua D.; Beran, Gregory J. O., E-mail: gregory.beran@ucr.edu [Department of Chemistry, University of California, Riverside, California 92521 (United States); Monaco, Stephen; Schatschneider, Bohdan [The Pennsylvania State University, The Eberly Campus, 2201 University Dr, Lemont Furnace, Pennsylvania 15456 (United States)

    2015-09-14

    We assess the quality of fragment-based ab initio isotropic {sup 13}C chemical shift predictions for a collection of 25 molecular crystals with eight different density functionals. We explore the relative performance of cluster, two-body fragment, combined cluster/fragment, and the planewave gauge-including projector augmented wave (GIPAW) models relative to experiment. When electrostatic embedding is employed to capture many-body polarization effects, the simple and computationally inexpensive two-body fragment model predicts both isotropic {sup 13}C chemical shifts and the chemical shielding tensors as well as both cluster models and the GIPAW approach. Unlike the GIPAW approach, hybrid density functionals can be used readily in a fragment model, and all four hybrid functionals tested here (PBE0, B3LYP, B3PW91, and B97-2) predict chemical shifts in noticeably better agreement with experiment than the four generalized gradient approximation (GGA) functionals considered (PBE, OPBE, BLYP, and BP86). A set of recommended linear regression parameters for mapping between calculated chemical shieldings and observed chemical shifts are provided based on these benchmark calculations. Statistical cross-validation procedures are used to demonstrate the robustness of these fits.

  15. Fragmentation of single-particle strength and the validity of the shell model

    International Nuclear Information System (INIS)

    Brand, M.G.E.; Rijsdijk, G.A.; Muller, F.A.; Allaart, K.; Dickhoff, W.H.

    1991-01-01

    The problem of missing spectroscopic strength in proton knock-out reactions is addressed by calculating this strength with a realistic interaction up to about a hundred MeV missing energy. An interaction suitably modified for short-range correlations (G-matrix) is employed in the calculation of the self-energy including all orbitals up to and including three major shells above the Fermi level for protons. The spectroscopic strength is obtained by solving the Dyson equation for the Green function with a self-energy up to second order in the interaction. Results for 48 Ca and 90 Zr are compared with recent (e,e'p) data. The calculated strength overestimates the data by about 10-15% of the independent particle shell-model (IPSM) sum rule. This is in accordance with what is expected from depletions calculated in infinite nuclear matter. Inclusion of higher order terms into the self-energy, especially the correlated motion of particles and holes, is found to be necessary to reproduce the observed fragmentation of strength in the low-energy region. The widths of the strength distributions compare well with empirical formulas which have been deduced from optical potentials. The validity of the conventional shell-model picture is connected with the relevance of Landau's quasiparticle picture for strongly interacting Fermi systems. (orig.)

  16. Non-ideal magnetohydrodynamic simulations of the two-stage fragmentation model for cluster formation

    International Nuclear Information System (INIS)

    Bailey, Nicole D.; Basu, Shantanu

    2014-01-01

    We model molecular cloud fragmentation with thin-disk, non-ideal magnetohydrodynamic simulations that include ambipolar diffusion and partial ionization that transitions from primarily ultraviolet-dominated to cosmic-ray-dominated regimes. These simulations are used to determine the conditions required for star clusters to form through a two-stage fragmentation scenario. Recent linear analyses have shown that the fragmentation length scales and timescales can undergo a dramatic drop across the column density boundary that separates the ultraviolet- and cosmic-ray-dominated ionization regimes. As found in earlier studies, the absence of an ionization drop and regular perturbations leads to a single-stage fragmentation on pc scales in transcritical clouds, so that the nonlinear evolution yields the same fragment sizes as predicted by linear theory. However, we find that a combination of initial transcritical mass-to-flux ratio, evolution through a column density regime in which the ionization drop takes place, and regular small perturbations to the mass-to-flux ratio is sufficient to cause a second stage of fragmentation during the nonlinear evolution. Cores of size ∼0.1 pc are formed within an initial fragment of ∼pc size. Regular perturbations to the mass-to-flux ratio also accelerate the onset of runaway collapse.

  17. Tests of models for parton fragmentation in e+e- annihilation

    International Nuclear Information System (INIS)

    Gary, J.W.

    1985-11-01

    We examine the distribution of particles in the three jet events of e + e - annihilation. The data was collected with the PEP-4/Time Projection Chamber detector at 29 GeV center-of-mass energy at PEP. The experimental distributions are compared to the predictions of several fragmentation models which describe the transition of quarks and gluons into hadrons. In particular, our study emphasizes the three fragmentation models which are currently in widest use: the Lund string model, the Webber cluster model and the independent fragmentation model. These three models each possess different Lorentz frame structures for the distribution of hadron sources relative to the overall event c.m. in three jet events. The Lund string and independent fragmentation models are tuned to describe global event properties of our multihadronic annihilation event sample. This tuned Lund string model provides a good description of the distribution of particles between jet axes in three jet events, while the independent fragmentation model does not. We verify that the failure of the independent fragmentation model is not a consequence of parameter tuning or of model variant. The Webber cluster model, which is untuned, does not describe the absolute particle densities between jets but correctly predicts the ratios of those densities, which are less sensitive to the tuning. These results provide evidence that the sources of hadrons are boosted with respect to the overall center-of-mass in three jet events, with components of motion normal to the jet axes. The distribution of particles close to jet axes provides additional support for this conclusion. 94 refs

  18. Detonation and fragmentation modeling for the description of large scale vapor explosions

    International Nuclear Information System (INIS)

    Buerger, M.; Carachalios, C.; Unger, H.

    1985-01-01

    The thermal detonation modeling of large-scale vapor explosions is shown to be indispensable for realistic safety evaluations. A steady-state as well as transient detonation model have been developed including detailed descriptions of the dynamics as well as the fragmentation processes inside a detonation wave. Strong restrictions for large-scale vapor explosions are obtained from this modeling and they indicate that the reactor pressure vessel would even withstand explosions with unrealistically high masses of corium involved. The modeling is supported by comparisons with a detonation experiment and - concerning its key part - hydronamic fragmentation experiments. (orig.) [de

  19. Model tool to describe chemical structures in XML format utilizing structural fragments and chemical ontology.

    Science.gov (United States)

    Sankar, Punnaivanam; Alain, Krief; Aghila, Gnanasekaran

    2010-05-24

    We have developed a model structure-editing tool, ChemEd, programmed in JAVA, which allows drawing chemical structures on a graphical user interface (GUI) by selecting appropriate structural fragments defined in a fragment library. The terms representing the structural fragments are organized in fragment ontology to provide a conceptual support. ChemEd describes the chemical structure in an XML document (ChemFul) with rich semantics explicitly encoding the details of the chemical bonding, the hybridization status, and the electron environment around each atom. The document can be further processed through suitable algorithms and with the support of external chemical ontologies to generate understandable reports about the functional groups present in the structure and their specific environment.

  20. A Fragment-Cloud Model for Breakup of Asteroids with Varied Internal Structures

    Science.gov (United States)

    Wheeler, Lorien; Mathias, Donovan; Stokan, Ed; Brown, Peter

    2016-01-01

    As an asteroid descends toward Earth, it deposits energy in the atmosphere through aerodynamic drag and ablation. Asteroid impact risk assessments rely on energy deposition estimates to predict blast overpressures and ground damage that may result from an airburst, such as the one that occurred over Chelyabinsk, Russia in 2013. The rates and altitudes at which energy is deposited along the entry trajectory depend upon how the bolide fragments, which in turn depends upon its internal structure and composition. In this work, we have developed an analytic asteroid fragmentation model to assess the atmospheric energy deposition of asteroids with a range of structures and compositions. The modeling approach combines successive fragmentation of larger independent pieces with aggregate debris clouds released with each fragmentation event. The model can vary the number and masses of fragments produced, the amount of mass released as debris clouds, the size-strength scaling used to increase the robustness of smaller fragments, and other parameters. The initial asteroid body can be seeded with a distribution of independent fragment sizes amid a remaining debris mass to represent loose rubble pile conglomerations, can be given an outer regolith later, or can be defined as a coherent or fractured monolith. This approach enables the model to represent a range of breakup behaviors and reproduce detailed energy deposition features such as multiple flares due to successive burst events, high-altitude regolith blow-off, or initial disruption of rubble piles followed by more energetic breakup of the constituent boulders. These capabilities provide a means to investigate sensitivities of ground damage to potential variations in asteroid structure.

  1. Primer on nuclear exchange models

    Energy Technology Data Exchange (ETDEWEB)

    Hafemeister, David [Physics Department, Cal Poly University, San Luis Obispo, California (United States)

    2014-05-09

    Basic physics is applied to nuclear force exchange models between two nations. Ultimately, this scenario approach can be used to try and answer the age old question of 'how much is enough?' This work is based on Chapter 2 of Physics of Societal Issues: Calculations on National Security, Environment and Energy (Springer, 2007 and 2014)

  2. Modeling the fine fragmentation following the triggering stage of a vapor explosion

    International Nuclear Information System (INIS)

    Darbord, I.

    1997-01-01

    In the frame of PWR severe accidents, where the core melt, this thesis studies one of the stages of an FCI (fuel coolant interaction) or vapor explosion. An FCI is a rapid evaporation of a coolant when it comes into contact with a hot liquid. More precisely, the subject of this study is the triggering stage of the FCI, when a fuel drop of diameter around one centimeter breaks up into many fragments, diameter of which is around a hundred micrometers. The model describes the cyclic collapse and growth of a vapor bubble around the fuel droplet and its fragmentation. The main features of the model are: - the destabilization of the film or the vapor bubble due to the growth of Rayleigh-Taylor instabilities (those form coolant jets that contact the fuel surface); - The mechanisms of fragmentation, following the contacts (in the case of entrapment of a certain amount of coolant in the fuel, the entrapped coolant evaporates violently after it has been heated to the homogeneous nucleation temperature); - the transient heat transfer from the fragments to the coolant and the elevated vapor production, which leads to an important expansion of the bubble (about this point, the cooling of the fragments has been described by a transient heat transfer coefficient linked to nucleate boiling). The results of the model show good agreement with experimental data. (Author)

  3. Fragments of reminiscences and exactly solvable nonrelativistic quantum models

    International Nuclear Information System (INIS)

    Zakhariev, B.N.

    1994-01-01

    Some exactly solvable nonrelativistic quantum models are discussed. Special attention is paid to the quantum inverse problem. It is pointed out that by analyzing the inverse problem pictures one can get a deeper insight into the laws of the microworld and acquire the ability to make the qualitative predictions without computers and formulae. 5 refs

  4. (Studies of target fragmentation in intermediate energy, relativistic and ultra-relativistic nuclear collisions)

    Energy Technology Data Exchange (ETDEWEB)

    Loveland, W.D.

    1991-08-01

    The work described herein is part of a project involving the study of low energy (< 10 MeV/A), intermediate energy (10--100 MeV/A) and relativistic (> 250 MeV/A) heavy ion reactions. In the low energy regime, we published a monograph on the properties of the heaviest elements and used that publication as a basis for making a set of best'' semi-empirical predictions of heavy element decay properties. The intermediate energy research effort focussed upon the completion of studies already begun and the initiation of a number of new experiments. In our study of a interaction of 21 MeV/nucleon {sup 129}Xe with {sup 197}Au, we compared the characteristics of the observed deep inelastic phenomena with various models of dissipative reactions and found significant discrepancies between observations and predictions. These discrepancies seemed to be caused by an improper treatment of pre-equilibrium in the early stages of the collision. In our study of the relativistic interaction of 400 MeV/nucleon {sup 12}C with {sup 197}Au, we reported the first direct physical measurement of the properties of the spallation residues from a nucleus-nucleus collision. We found the residue energies to be much lower than those predicted by the intranuclear cascade model, indicating some substantial modifications of that model are needed. But, we also found, indications of significant, non-zero values of the residue transverse momentum, a finding that calls into question the interpretation of a number of radiochemical recoil studies of the kinematics of high energy reactions. A program of performing numerical simulations of intermediate and high energy nuclear collisions using the QMD model was initiated.

  5. [Studies of target fragmentation in intermediate energy, relativistic and ultra-relativistic nuclear collisions

    International Nuclear Information System (INIS)

    Loveland, W.D.

    1991-08-01

    The work described herein is part of a project involving the study of low energy ( 250 MeV/A) heavy ion reactions. In the low energy regime, we published a monograph on the properties of the heaviest elements and used that publication as a basis for making a set of ''best'' semi-empirical predictions of heavy element decay properties. The intermediate energy research effort focussed upon the completion of studies already begun and the initiation of a number of new experiments. In our study of a interaction of 21 MeV/nucleon 129 Xe with 197 Au, we compared the characteristics of the observed deep inelastic phenomena with various models of dissipative reactions and found significant discrepancies between observations and predictions. These discrepancies seemed to be caused by an improper treatment of pre-equilibrium in the early stages of the collision. In our study of the relativistic interaction of 400 MeV/nucleon 12 C with 197 Au, we reported the first direct physical measurement of the properties of the spallation residues from a nucleus-nucleus collision. We found the residue energies to be much lower than those predicted by the intranuclear cascade model, indicating some substantial modifications of that model are needed. But, we also found, indications of significant, non-zero values of the residue transverse momentum, a finding that calls into question the interpretation of a number of radiochemical recoil studies of the kinematics of high energy reactions. A program of performing numerical simulations of intermediate and high energy nuclear collisions using the QMD model was initiated

  6. Peripheral collisions of 2 GeV/nucleon Fe nuclei in nuclear emulsion. I. Light projectile fragments

    International Nuclear Information System (INIS)

    Friedlander, E.M.; Crawford, H.J.; Gimpel, R.W.; Greiner, D.E.; Heckman, H.H.; Lindstrom, P.J.

    1978-01-01

    Observations on 374 collisions of 1.88-GeV/nucleon Fe nuclei in Ilford G-5 nuclear track emulsion, in which at least one projectle fragment of Z > = 3 was emitted within a 6 0 cone, revealed several features of projectile breakup. The onset of copious multiple fragmentation was observed. The relatively high α-particle multiplicities allowed for the first time a study of the α multiplicity distribution; a Poisson distribution gave an excellent fit. The data showed a significant enhancement of α-particle pairs with very small relative momenta. The transverse momentum distributions, which should reflect best the thermal motion in the projectile system, are in flagrant discrepancy with theoretical predictions; the distributions show a marked target dependence. The charges of all projectile fragments up to B were determined by measurement of gap-length distributions. Events with N/sub h/ = 0 are a class apart from the rest of the events; between N/sub h/ = 1 and N/sub h/ = 9 there is surprisingly little change in most parameters. 4 figures

  7. Interactions of $^{16}$O Projectile and its Fragments in Nuclear Emulsion at about 60 and 200 GeV/nucleon

    CERN Multimedia

    2002-01-01

    The aim of the experiment is to measure the multiplicity ``$ n _{s} $'' and pseudo-rapidity ``$\\eta$'' of the shower particles ($\\beta$~$\\geq$~0.7) produced in different types of collisions (peripheral, semi-central and central), of $^{16}$O and $^{32}$S in nuclear emulsions. The multiplicities and angular distributions of both the grey ``$ n _{g} $'' (mainly due to knock- on and recoil protons), and black ``$ n _{b} $'' (slow evaporated target fragments) particles, and the inter-correlation between them are studied. \\\\ \\\\ The yield, charge and angular distributions of produced relativistic projectile fragments P.F.S., for $ Z _{P} . _{F} . $ $\\geq$~2 are measured and their interactions in emulsions are investigated. \\\\ \\\\ The study of the mean free paths for the projectile fragments with Z $\\geq$ 3 produced from 200~A~GeV $^{16}$ 0 interactions were performed, which show the absence of the anomalous phenomena. \\\\ \\\\ The possible production of zero-spin light neutral scaler bosons and pseudoscaler bosons from...

  8. Human modeling in nuclear engineering

    International Nuclear Information System (INIS)

    Yoshikawa, Hidekazu; Furuta, Kazuo.

    1994-01-01

    Review on progress of research and development on human modeling methods is made from the viewpoint of its importance on total man-machine system reliability surrounding nuclear power plant operation. Basic notions on three different approaches of human modeling (behavioristics, cognitives and sociologistics) are firstly introduced, followed by the explanation of fundamental scheme to understand human cognitives at man-machine interface and the mechanisms of human error and its classification. Then, general methodologies on human cognitive model by AI are explained with the brief summary of various R and D activities now prevailing in the human modeling communities around the world. A new method of dealing with group human reliability is also introduced which is based on sociologistic mathematical model. Lastly, problems on human model validation are discussed, followed by the introduction of new experimental method to estimate human cognitive state by psycho-physiological measurement, which is a new methodology plausible for human model validation. (author)

  9. Experiments on the nuclear fragmentation and on the production of radioactive beams for direct reactions

    International Nuclear Information System (INIS)

    Weiss, A.

    1993-06-01

    In April 1992 at the GSI a prototype experiment on the production and study of the double-magic radioactive nucleus 56 Ni was successfully performed with proton scattering in inverse kinematics. A 350 MeV/u 56 Ni primary beam from the heavy ion synchrotron SIS was fragmented in a 4/g/cm 2 thick beryllium target. The separation of the formed isotopes ensued in the fragment separator FRS, which was operated in the achromatic mode with a degrader. Production cross sections for a whole series of fragments in the range 29≥Z≥19 and 57≥A≥41 were obtained. It succeeded to detect proton-rich isotopes at the boundary of the stability as for instance 52 Co, 51 Co, 50 Co, or 52 Ni and to determine for the first time their production cross sections. A further part of this thesis with regard to experiments with radioactive beams were first test experiments at the experimental storage ring ESR. The spotlight held luminosity measurements at the internal gas target with cooled, stable proton beam. For this the elastic scattering was stuided in inverse kinematics in the Rutherford range. Studied were different projectile beams (Ne, Xe) at energies of 150 MeV/u respectively 250 MeV/u and gas jets of nitrogen, argon, and hydrogen. The measured energy spectra of the recoils are in agreement with simulation calculations

  10. [Preparation of monoclonal antibody against 4-amylphenol and homology modeling of its Fv fragment].

    Science.gov (United States)

    Cheng, Lei; Wu, Haizhen; Fei, Jing; Zhang, Lujia; Ye, Jiang; Zhang, Huizhan

    2017-03-01

    Objective To prepare and characterize a monoclonal antibody (mAb) against 4-amylphenol (4-AP), clone its cDNA sequence and make homology modeling for its Fv fragment. Methods A high-affinity anti-4-AP mAb was generated from a hybridoma cell line F10 using electrofusion between splenocytes from APA-BSA-immunized mouse and Sp2/0 myeloma cells. Then we extracted the mRNA of F10 cells and cloned the cDNA of mAb. The homology modeling and molecular docking of its Fv fragment was conducted with biological software. Results Under the optimum conditions, the ic-ELISA equation was y=A 2 +(A 1 -A 2 )/(1+(x/x 0 ) p ) (A 1 =1.28; A 2 =-0.066; x 0 =12560.75; p=0.74) with a correlation coefficient (R 2 ) of 0.997. The lowest detectable limit was 0.65 μg/mL. The heavy and light chains of mAb respectively belonged to IgG1 and Kappa. The homology modeling and molecular docking studies revealed that the binding of 4-Ap and mAb was attributed to the hydrogen bond and hydrophobic interactions. Conclusion The study successfully established a stable 4-AP mAb-secreting hybridoma cell line. The study on spatial structure of Fv fragment using homology modeling provided a reference for the development and design of single chain variable fragments.

  11. Automated main-chain model building by template matching and iterative fragment extension

    International Nuclear Information System (INIS)

    Terwilliger, Thomas C.

    2003-01-01

    A method for automated macromolecular main-chain model building is described. An algorithm for the automated macromolecular model building of polypeptide backbones is described. The procedure is hierarchical. In the initial stages, many overlapping polypeptide fragments are built. In subsequent stages, the fragments are extended and then connected. Identification of the locations of helical and β-strand regions is carried out by FFT-based template matching. Fragment libraries of helices and β-strands from refined protein structures are then positioned at the potential locations of helices and strands and the longest segments that fit the electron-density map are chosen. The helices and strands are then extended using fragment libraries consisting of sequences three amino acids long derived from refined protein structures. The resulting segments of polypeptide chain are then connected by choosing those which overlap at two or more C α positions. The fully automated procedure has been implemented in RESOLVE and is capable of model building at resolutions as low as 3.5 Å. The algorithm is useful for building a preliminary main-chain model that can serve as a basis for refinement and side-chain addition

  12. Excited State Contributions to the Heavy Baryon Fragmentation Functions in a Quark-Diquark Model

    CERN Document Server

    Adamov, A D; Goldstein, Gary R.

    2001-01-01

    Spin dependent fragmentation functions for heavy flavor quarks to fragment into heavy baryons are calculated in a quark-diquark model. The production of intermediate spin 1/2 and 3/2 excited states is explicity included. The resulting $\\Lambda_b$ production rate and polarization at LEP energies are in agreement with experiment. The $\\Lambda_c$ and $\\Xi_c$ functions are also obtained. The spin independent $f_1(z)$ is compared to data. The integrated values for production rates agree with the data.

  13. Benchmarking nuclear models of FLUKA and GEANT4 for carbon ion therapy

    CERN Document Server

    Bohlen, TT; Quesada, J M; Bohlen, T T; Cerutti, F; Gudowska, I; Ferrari, A; Mairani, A

    2010-01-01

    As carbon ions, at therapeutic energies, penetrate tissue, they undergo inelastic nuclear reactions and give rise to significant yields of secondary fragment fluences. Therefore, an accurate prediction of these fluences resulting from the primary carbon interactions is necessary in the patient's body in order to precisely simulate the spatial dose distribution and the resulting biological effect. In this paper, the performance of nuclear fragmentation models of the Monte Carlo transport codes, FLUKA and GEANT4, in tissue-like media and for an energy regime relevant for therapeutic carbon ions is investigated. The ability of these Monte Carlo codes to reproduce experimental data of charge-changing cross sections and integral and differential yields of secondary charged fragments is evaluated. For the fragment yields, the main focus is on the consideration of experimental approximations and uncertainties such as the energy measurement by time-of-flight. For GEANT4, the hadronic models G4BinaryLightIonReaction a...

  14. Thermochemical Fragment Energy Method for Biomolecules: Application to a Collagen Model Peptide.

    Science.gov (United States)

    Suárez, Ernesto; Díaz, Natalia; Suárez, Dimas

    2009-06-09

    Herein, we first review different methodologies that have been proposed for computing the quantum mechanical (QM) energy and other molecular properties of large systems through a linear combination of subsystem (fragment) energies, which can be computed using conventional QM packages. Particularly, we emphasize the similarities among the different methods that can be considered as variants of the multibody expansion technique. Nevertheless, on the basis of thermochemical arguments, we propose yet another variant of the fragment energy methods, which could be useful for, and readily applicable to, biomolecules using either QM or hybrid quantum mechanical/molecular mechanics methods. The proposed computational scheme is applied to investigate the stability of a triple-helical collagen model peptide. To better address the actual applicability of the fragment QM method and to properly compare with experimental data, we compute average energies by carrying out single-point fragment QM calculations on structures generated by a classical molecular dynamics simulation. The QM calculations are done using a density functional level of theory combined with an implicit solvent model. Other free-energy terms such as attractive dispersion interactions or thermal contributions are included using molecular mechanics. The importance of correcting both the intermolecular and intramolecular basis set superposition error (BSSE) in the QM calculations is also discussed in detail. On the basis of the favorable comparison of our fragment-based energies with experimental data and former theoretical results, we conclude that the fragment QM energy strategy could be an interesting addition to the multimethod toolbox for biomolecular simulations in order to investigate those situations (e.g., interactions with metal clusters) that are beyond the range of applicability of common molecular mechanics methods.

  15. Modeling Fragment Simulating Projectile Penetration into Steel Plates Using Finite Elements and Meshfree Particles

    Directory of Open Access Journals (Sweden)

    James O’Daniel

    2011-01-01

    Full Text Available Simulating fragment penetration into steel involves complicated modeling of severe behavior of the materials through multiple phases of response. Penetration of a fragment-like projectile was simulated using finite element (FE and meshfree particle formulations. Extreme deformation and failure of the material during the penetration event were modeled with several approaches to evaluate each as to how well it represents the actual physics of the material and structural response. A steel Fragment Simulating Projectile (FSP – designed to simulate a fragment of metal from a weapon casing – was simulated for normal impact into a flat square plate. A range of impact velocities was used to examine levels of exit velocity ranging from relatively small to one on the same level as the impact velocity. The numerical code EPIC, used for all the simulations presented herein, contains the element and particle formulations, as well as the explicit methodology and constitutive models needed to perform these simulations. These simulations were compared against experimental data, evaluating the damage caused to the projectile and the target plates, as well as comparing the residual velocity when the projectile perforated the target.

  16. Automated main-chain model building by template matching and iterative fragment extension.

    Science.gov (United States)

    Terwilliger, Thomas C

    2003-01-01

    An algorithm for the automated macromolecular model building of polypeptide backbones is described. The procedure is hierarchical. In the initial stages, many overlapping polypeptide fragments are built. In subsequent stages, the fragments are extended and then connected. Identification of the locations of helical and beta-strand regions is carried out by FFT-based template matching. Fragment libraries of helices and beta-strands from refined protein structures are then positioned at the potential locations of helices and strands and the longest segments that fit the electron-density map are chosen. The helices and strands are then extended using fragment libraries consisting of sequences three amino acids long derived from refined protein structures. The resulting segments of polypeptide chain are then connected by choosing those which overlap at two or more C(alpha) positions. The fully automated procedure has been implemented in RESOLVE and is capable of model building at resolutions as low as 3.5 A. The algorithm is useful for building a preliminary main-chain model that can serve as a basis for refinement and side-chain addition.

  17. Quasiparticle-phonon nuclear model

    International Nuclear Information System (INIS)

    Soloviev, V.G.

    1977-01-01

    The general assumptions of the quasiparticle-phonon model of complex nuclei are given. The choice of the model hamiltonian as an average field and residual forces is discussed. The phonon description and quasiparticle-phonon interaction are presented. The system of basic equations and their approximate solutions are obtained. The approximation is chosen so as to obtain the most correct description of few-quasiparticle components rather than of the whole wave function. The method of strenght functions is presented, which plays a decisive role in practical realization of the quasiparticle-phonon model for the description of some properties of complex nuclei. The range of applicability of the quasiparticle-phonon nuclear model is determined as few-quasiparticle components of the wave functions at low, intermediate and high excitation energies averaged in a certain energy interval

  18. Partial splenectomy and autotransplantation of splenic fragments in pigs: a model for prevention of septicemia

    International Nuclear Information System (INIS)

    Pabst, R.; Binns, R.M.

    1986-01-01

    Normal young piglets and miniature piglets of the Gottingen breed were used as animal models for autotransplantation of splenic fragments. In pigs, regeneration kinetics seem to be comparable to man. Even after six mo, only small splenic nodules with a reduced blood flow were found. No effective stimulator of splenic regeneration has been found for pigs. Pig spleen size and blood supply enable partial splenectomies and ligation of the splenic artery which are models for spleen surgery in man

  19. Physics-Based Fragment Acceleration Modeling for Pressurized Tank Burst Risk Assessments

    Science.gov (United States)

    Manning, Ted A.; Lawrence, Scott L.

    2014-01-01

    As part of comprehensive efforts to develop physics-based risk assessment techniques for space systems at NASA, coupled computational fluid and rigid body dynamic simulations were carried out to investigate the flow mechanisms that accelerate tank fragments in bursting pressurized vessels. Simulations of several configurations were compared to analyses based on the industry-standard Baker explosion model, and were used to formulate an improved version of the model. The standard model, which neglects an external fluid, was found to agree best with simulation results only in configurations where the internal-to-external pressure ratio is very high and fragment curvature is small. The improved model introduces terms that accommodate an external fluid and better account for variations based on circumferential fragment count. Physics-based analysis was critical in increasing the model's range of applicability. The improved tank burst model can be used to produce more accurate risk assessments of space vehicle failure modes that involve high-speed debris, such as exploding propellant tanks and bursting rocket engines.

  20. Nuclear fragmentation in central collisions: Ni + Au from 32 to 90 A*MeV; Fragmentation dans les collisions centrales du systeme Ni + Au de 32 a 90 A MeV

    Energy Technology Data Exchange (ETDEWEB)

    Bellaize, N

    2000-11-03

    Heavy ion collisions are one of tools for studying nuclear system far away from its equilibrium state. This work concerns the most violent collisions in the Ni + Au system for incident energies ranging from 32 up to 90 AMeV. These events were detected with the multidetector INDRA and selected by the Principal Component Analysis (multidimensional analysis). This method classifies the events according their detection features and their degree of dissipation. We observed two deexcitation mechanisms: a fusion/fission - evaporation process and a multifragmentation process. Those two coexist from 32 to 52 AMeV whereas only one subsists at 90 AMeV. For those two mechanisms, an component was observed which seems to be linked to the initial phase of the reaction. The energy fluctuations of this component leads to variations in the energy deposit which determines the deexcitation of the system. The experimental multifragmentation data of the Ni + Au system (52 and 90 AMeV) were compared to the predictions of a statistical model and to the experimental data of the system Xe + Sn at 50 AMeV (also detected with INDRA). These comparisons show the lack of collective radial energy for fragments (Z{>=}10) in the Ni + Au system, and show that the degree of multifragmentation depends of the thermal excitation energy. Mean kinetic energies of particles and lights fragments (Z{>=}10) are larger in the Ni + Au system than the Xe + Sn system. This observation shows that these particles are more sensitive to the entrance channel for an asymmetric system than for a symmetric system (for the same number of nucleons). (author)

  1. Measurement of the energy spectrum of {sup 252}Cf fission fragments using nuclear track detectors and digital image processing

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa, G.; Golzarri, J. I. [UNAM, Instituto de Fisica, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Castano, V. M. [UNAM, Centro de Fisica Aplicada y Tecnologia Avanzada, Boulevard Juriquilla 3001, Santiago de Queretaro, 76230 Queretaro (Mexico); Gaso, I. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico); Mena, M.; Segovia, N. [UNAM, Instituto de Geofisica, Circuito de la Investigacion Cientifica, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)

    2010-02-15

    The energy spectrum of {sup 252}Cf fission fragments was measured using nuclear track detectors and digital image analysis system. The detection material was fused silica glass. The detectors were chemically etched in an 8% HF solution. After experimenting with various etching time, it was found that the best resolution of the track diameter distribution was obtained after 30 minutes of etching. Both Gaussian and Lorentzian curves were fit to the track diameter distribution histograms and used to determine the basic parameters of the distribution of the light (N{sub L}) and heavy (N{sub H}) formed peaks and the minimum of the central valley (N{sub V}). Advantages of the method presented here include the fully-automated analysis process, the low cost of the nuclear track detectors and the simplicity of the nuclear track method. The distribution resolution obtained by this method is comparable with the resolution obtained by electronic analysis devices. The descriptive variables calculated were very close to those obtained by other methods based on the use of semiconductor detectors. (Author)

  2. Process and data fragmentation-oriented enterprise network integration with collaboration modelling and collaboration agents

    Science.gov (United States)

    Li, Qing; Wang, Ze-yuan; Cao, Zhi-chao; Du, Rui-yang; Luo, Hao

    2015-08-01

    With the process of globalisation and the development of management models and information technology, enterprise cooperation and collaboration has developed from intra-enterprise integration, outsourcing and inter-enterprise integration, and supply chain management, to virtual enterprises and enterprise networks. Some midfielder enterprises begin to serve for different supply chains. Therefore, they combine related supply chains into a complex enterprise network. The main challenges for enterprise network's integration and collaboration are business process and data fragmentation beyond organisational boundaries. This paper reviews the requirements of enterprise network's integration and collaboration, as well as the development of new information technologies. Based on service-oriented architecture (SOA), collaboration modelling and collaboration agents are introduced to solve problems of collaborative management for service convergence under the condition of process and data fragmentation. A model-driven methodology is developed to design and deploy the integrating framework. An industrial experiment is designed and implemented to illustrate the usage of developed technologies in this paper.

  3. Fragment-based modelling of single stranded RNA bound to RNA recognition motif containing proteins

    Science.gov (United States)

    de Beauchene, Isaure Chauvot; de Vries, Sjoerd J.; Zacharias, Martin

    2016-01-01

    Abstract Protein-RNA complexes are important for many biological processes. However, structural modeling of such complexes is hampered by the high flexibility of RNA. Particularly challenging is the docking of single-stranded RNA (ssRNA). We have developed a fragment-based approach to model the structure of ssRNA bound to a protein, based on only the protein structure, the RNA sequence and conserved contacts. The conformational diversity of each RNA fragment is sampled by an exhaustive library of trinucleotides extracted from all known experimental protein–RNA complexes. The method was applied to ssRNA with up to 12 nucleotides which bind to dimers of the RNA recognition motifs (RRMs), a highly abundant eukaryotic RNA-binding domain. The fragment based docking allows a precise de novo atomic modeling of protein-bound ssRNA chains. On a benchmark of seven experimental ssRNA–RRM complexes, near-native models (with a mean heavy-atom deviation of <3 Å from experiment) were generated for six out of seven bound RNA chains, and even more precise models (deviation < 2 Å) were obtained for five out of seven cases, a significant improvement compared to the state of the art. The method is not restricted to RRMs but was also successfully applied to Pumilio RNA binding proteins. PMID:27131381

  4. Modeling fragmentation with new high order finite element technology and node splitting

    Directory of Open Access Journals (Sweden)

    Olovsson Lars

    2015-01-01

    Full Text Available The modeling of fragmentation has historically been linked to the weapons industry where the main goal is to optimize a bomb or to design effective blast shields. Numerical modeling of fragmentation from dynamic loading has traditionally been modeled by legacy finite element solvers that rely on element erosion to model material failure. However this method results in the removal of too much material. This is not realistic as retaining the mass of the structure is critical to modeling the event correctly. We propose a new approach implemented in the IMPETUS AFEA SOLVER® based on the following: New High Order Finite Elements that can easily deal with very large deformations; Stochastic distribution of initial damage that allows for a non homogeneous distribution of fragments; and a Node Splitting Algorithm that allows for material fracture without element erosion that is mesh independent. The approach is evaluated for various materials and scenarios: -Titanium ring electromagnetic compression; Hard steel Taylor bar impact, Fused silica Taylor bar impact, Steel cylinder explosion, The results obtained from the simulations are representative of the failure mechanisms observed experimentally. The main benefit of this approach is good energy conservation (no loss of mass and numerical robustness even in complex situations.

  5. The nuclear single particle model

    International Nuclear Information System (INIS)

    Mang, H.

    1985-01-01

    Twenty years ago in December 1963 one half of the Nobel prize in Physics was awarded to Maria Goeppert-Mayer and Johannes Daniel Jensen for their work on the nuclear shell model. They suggested independently that a strong spin-orbit force with the opposite sign of the one known from atomic physics should be added to the shell-model potential. This proved to be the crucial new idea, because then all the bits of and pieces of evidence that had accumulated over the years fell into place. The author begins with the basic assumption: In a nucleus nucleons move almost independently of each other in an average or shell-model potential. He then provides experimental evidence plausibility arguments and mathematical deductions

  6. SPY: a new scission-point model based on microscopic inputs to predict fission fragment properties

    Energy Technology Data Exchange (ETDEWEB)

    Panebianco, Stefano; Lemaître, Jean-Francois; Sida, Jean-Luc [CEA Centre de Saclay, Gif-sur-Ivette (France); Dubray, Noëel [CEA, DAM, DIF, Arpajon (France); Goriely, Stephane [Institut d' Astronomie et d' Astrophisique, Universite Libre de Bruxelles, Brussels (Belgium)

    2014-07-01

    Despite the difficulty in describing the whole fission dynamics, the main fragment characteristics can be determined in a static approach based on a so-called scission-point model. Within this framework, a new Scission-Point model for the calculations of fission fragment Yields (SPY) has been developed. This model, initially based on the approach developed by Wilkins in the late seventies, consists in performing a static energy balance at scission, where the two fragments are supposed to be completely separated so that their macroscopic properties (mass and charge) can be considered as fixed. Given the knowledge of the system state density, averaged quantities such as mass and charge yields, mean kinetic and excitation energy can then be extracted in the framework of a microcanonical statistical description. The main advantage of the SPY model is the introduction of one of the most up-to-date microscopic descriptions of the nucleus for the individual energy of each fragment and, in the future, for their state density. These quantities are obtained in the framework of HFB calculations using the Gogny nucleon-nucleon interaction, ensuring an overall coherence of the model. Starting from a description of the SPY model and its main features, a comparison between the SPY predictions and experimental data will be discussed for some specific cases, from light nuclei around mercury to major actinides. Moreover, extensive predictions over the whole chart of nuclides will be discussed, with particular attention to their implication in stellar nucleosynthesis. Finally, future developments, mainly concerning the introduction of microscopic state densities, will be briefly discussed. (author)

  7. Uniformity measure for power-law mass spectrum in nuclear fragmentation

    International Nuclear Information System (INIS)

    Wislicki, W.

    1992-11-01

    Description is given in terms of the Renyi entropy and the uniformity for the canonical ensemble, the grand canonical ensemble and the power-law probability measures. The study is presented of the power-law spectra of cluster masses observed in nuclear interactions in the vicinity of the liquid-gas transition point. 6 figs., 1 tab., 15 refs. (author)

  8. MODELLING OF NUCLEAR FUEL CLADDING TUBES CORROSION

    Directory of Open Access Journals (Sweden)

    Miroslav Cech

    2016-12-01

    Full Text Available This paper describes materials made of zirconium-based alloys used for nuclear fuel cladding fabrication. It is focused on corrosion problems their theoretical description and modeling in nuclear engineering.

  9. Determination of aromatic fragment content in phenol-containing fractions of solid fuel conversion products using nuclear magnetic resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kanitskaya, L.V.; Kushnarev, D.F.; Polonov, V.M.; Kalabin, G.A.

    1986-03-01

    Optimum conditions are determined for obtaining quantitative nuclear magnetic resonance /sup 13/C spectra of fragments in phenol-containing fraction of coal products. Causes are analyzed of residual signals in spectra of un-protonized carbon atoms. The tests were carried out on: low-temperature carbonization tar and phenol fraction obtained during medium-temperature coking of Cherenkhovskii coal (which contains 84.13% C; 9.68% H; 1.23% S; 4.96% O); products of tar hydrogenation with various phenol content; standard phenol mixture. It was found that quantitative determination of aromatic fraction content in coal conversion products and other phenol- and amine-containing complex mixtures, using NMR spectroscopy requires the addition of dimethylsulfide or acetone in order to suppress specific interactions of phenols (amines) with relaxants and obtain quantitative subspectra of Tertiary and Quaternary aromatic carbon atoms. 16 references.

  10. Data for increase of Lymantria dispar male survival after topical application of single-stranded RING domain fragment of IAP-3 gene of its nuclear polyhedrosis virus

    Science.gov (United States)

    Oberemok, Volodymyr V.; Laikova, Kateryna V.; Zaitsev, Aleksei S.; Gushchin, Vladimir A.; Skorokhod, Oleksii A.

    2016-01-01

    This data article is related to the research article entitled “The RING for gypsy moth control: topical application of fragment of its nuclear polyhedrosis virus anti-apoptosis gene as insecticide” [1]. This article reports on significantly higher survival of gypsy moth Lymantria dispar male individuals in response to topical application of single-stranded DNA, based on RING (really interesting new gene) domain fragment of LdMNPV (L. dispar multicapsid nuclear polyhedrosis virus) IAP-3 (inhibitor of apoptosis) gene and acted as DNA insecticide. PMID:27054151

  11. Nuclear fuel cycle modelling using MESSAGE

    International Nuclear Information System (INIS)

    Guiying Zhang; Dongsheng Niu; Guoliang Xu; Hui Zhang; Jue Li; Lei Cao; Zeqin Guo; Zhichao Wang; Yutong Qiu; Yanming Shi; Gaoliang Li

    2017-01-01

    In order to demonstrate the possibilities of application of MESSAGE tool for the modelling of a Nuclear Energy System at the national level, one of the possible open nuclear fuel cycle options based on thermal reactors has been modelled using MESSAGE. The steps of the front-end and back-end of nuclear fuel cycle and nuclear reactor operation are described. The optimal structure for Nuclear Power Development and optimal schedule for introducing various reactor technologies and fuel cycle options; infrastructure facilities, nuclear material flows and waste, investments and other costs are demonstrated. (author)

  12. Clusters of DNA induced by ionizing radiation: formation of short DNA fragments. I. Theoretical modeling

    Science.gov (United States)

    Holley, W. R.; Chatterjee, A.

    1996-01-01

    We have developed a general theoretical model for the interaction of ionizing radiation with chromatin. Chromatin is modeled as a 30-nm-diameter solenoidal fiber comprised of 20 turns of nucleosomes, 6 nucleosomes per turn. Charged-particle tracks are modeled by partitioning the energy deposition between primary track core, resulting from glancing collisions with 100 eV or less per event, and delta rays due to knock-on collisions involving energy transfers >100 eV. A Monte Carlo simulation incorporates damages due to the following molecular mechanisms: (1) ionization of water molecules leading to the formation of OH, H, eaq, etc.; (2) OH attack on sugar molecules leading to strand breaks: (3) OH attack on bases; (4) direct ionization of the sugar molecules leading to strand breaks; (5) direct ionization of the bases. Our calculations predict significant clustering of damage both locally, over regions up to 40 bp and over regions extending to several kilobase pairs. A characteristic feature of the regional damage predicted by our model is the production of short fragments of DNA associated with multiple nearby strand breaks. The shapes of the spectra of DNA fragment lengths depend on the symmetries or approximate symmetries of the chromatin structure. Such fragments have subsequently been detected experimentally and are reported in an accompanying paper (B. Rydberg, Radiat, Res. 145, 200-209, 1996) after exposure to both high- and low-LET radiation. The overall measured yields agree well quantitatively with the theoretical predictions. Our theoretical results predict the existence of a strong peak at about 85 bp, which represents the revolution period about the nucleosome. Other peaks at multiples of about 1,000 bp correspond to the periodicity of the particular solenoid model of chromatin used in these calculations. Theoretical results in combination with experimental data on fragmentation spectra may help determine the consensus or average structure of the

  13. EDF fragment relocation model based on the displacement of rigid bodies

    International Nuclear Information System (INIS)

    Callu, C.; Baron, D.; Ruck, J.M.

    1997-01-01

    In order to release the restricting conditions imposed to the reactor operations with regards to PCMI (Pellet-Cladding Mechanical Interaction), the simulation of a fuel rod thermomechanical behavior has to be improved. The computer programming has to cope with the more and more sophisticated mathematical modellings induced by the complexity and the interdependence of the phenomena. Therefore EDF is developing a new code - CYRANO3 - since 1990 putting emphasis on its evolution capacities. Concerning more precisely the PCMI simulation, the pellet fragmentation and the fragments relocation is one of the major aspect one must account for. Thanks to recent analytical experiments, EDF developed a new modelling based on the displacement of rigid bodies and on the calculation of the interaction efforts between the fragments. This paper presents the basis of the model, its introduction within the CYRANO3 code and its calibration on a specific analytical experiment. The modelling is then tested against PWR fuel rods deformations from the EDF data base. The results are presented and discussed. (author)

  14. Analysis of single hyphal growth and fragmentation in submerged cultures using a population model

    DEFF Research Database (Denmark)

    Krabben, Preben; Nielsen, Søren; Michelsen, Michael Locht

    1997-01-01

    Descriptions of population dynamics in submerged cultures are important when studying the mechanisms of growth and fragmentation of filamentous microorganisms. Population models are traditionally formulated as population balance equations. Population models of filamentous morphology are difficult...... to solve because of random fragmentation, which introduces an integral term into the population balance equations. Balances for the systemic properties, e.g. concentration of hyphal elements, substrate concentration, average total hyphal length, and average number of growing tips, are set up. Based...... on these balances one can solve the inverse problem, i.e. determination of kinetic parameters directly from measurements of the hyphal morphology. Both a Monte Carlo method and a discretization method have been used to calculate the steady-state population distribution. The two methods are compared and the Monte...

  15. Full scale model studies of nuclear power stations for earthquake resistance

    International Nuclear Information System (INIS)

    Kirillov, A.P.; Ambriashvili, Ju. K.; Kozlov, A.V.

    Behaviour of nuclear power plants and its equipments under seismic action is not well understood. In the absence of well established method for aseismic deisgn of nuclear power plants and its equipments, it is necessary to carry out experimental investigations on models, fragments and full scale structures. The present study includes experimental investigations of different scale models and on existing nuclear power stations under impulse and explosion effects simulating seismic loads. The experimental work was aimed to develop on model test procedure for nuclear power station and the evaluation of the possible range of dynamic stresses in structures and pipe lines. The results of full-scale investigations of the nuclear reactor show a good agreement of dynamic characteristics of the model and the prototype. The study confirms the feasibility of simulation of model for nuclear power plants. (auth.)

  16. Bulk plasma fragmentation in a C4F8 inductively coupled plasma: A hybrid modeling study

    International Nuclear Information System (INIS)

    Zhao, Shu-Xia; Zhang, Yu-Ru; Gao, Fei; Wang, You-Nian; Bogaerts, Annemie

    2015-01-01

    A hybrid model is used to investigate the fragmentation of C 4 F 8 inductive discharges. Indeed, the resulting reactive species are crucial for the optimization of the Si-based etching process, since they determine the mechanisms of fluorination, polymerization, and sputtering. In this paper, we present the dissociation degree, the density ratio of F vs. C x F y (i.e., fluorocarbon (fc) neutrals), the neutral vs. positive ion density ratio, details on the neutral and ion components, and fractions of various fc neutrals (or ions) in the total fc neutral (or ion) density in a C 4 F 8 inductively coupled plasma source, as well as the effect of pressure and power on these results. To analyze the fragmentation behavior, the electron density and temperature and electron energy probability function (EEPF) are investigated. Moreover, the main electron-impact generation sources for all considered neutrals and ions are determined from the complicated C 4 F 8 reaction set used in the model. The C 4 F 8 plasma fragmentation is explained, taking into account many factors, such as the EEPF characteristics, the dominance of primary and secondary processes, and the thresholds of dissociation and ionization. The simulation results are compared with experiments from literature, and reasonable agreement is obtained. Some discrepancies are observed, which can probably be attributed to the simplified polymer surface kinetics assumed in the model

  17. In vitro and in vivo tumor models for studies of distribution of radiolabelled monoclonal antibodies and fragments

    International Nuclear Information System (INIS)

    Buchegger, F.; Halpern, S.E.; Sutherland, R.M.; Schreyer, M.; Mach, J.P.; Rochester Univ., NY

    1986-01-01

    Colon carcinoma multicellular spheroids were incubated in vitro with radiolabelled MAbs. The more rapid penetration of fragments as compared to intact MAbs was clearly demonstrated. For the study of antibody localization in tumors in vivo, the model of nude mice with ligated kidneys was used. Although very artificial, this model allowed to demonstrate that, without urinary excretion, Fab fragments accumulated more rapidly into the tumor than intact MAbs and disappeared faster from the blood. This difference was less striking for F(ab') 2 fragments. In the liver a decreased accumulation of both types of fragments as compared to intact MAbs was observed. Concerning radio-immunotherapy we think that Fab fragments are not useful because of their too short half-life the circulation and in tumor and because they will probably be too toxic for the kidneys. Intact MAbs and F(ab') 2 fragments have each their advantages. Intact MAbs show highest tumor accumulation in mice without ligated kidney, however, they remain mostly on the periphery of tumor nodules, as shown by autoradiography. F(ab') 2 fragments have been found to penetrate deeper into the tumor and to accumulate less in the liver. It might be therefore an advantage to combine intact MAbs with F(ab') 2 fragments, so that in the tumor two different regions could be attacked whereas in normal tissues toxicity could be distributed to different organs such as to the liver with intact MAbs and to the kidney with F(ab') 2 fragments. (orig.) [de

  18. Nuclear Physics——Energy Dependence of String Fragmentation Function and φ Meson Production

    Institute of Scientific and Technical Information of China (English)

    SABen-hao; WANGZhong-qi

    2003-01-01

    Strangeness enhancement was suggested in the early eighties as one of the most promising signatures for the creation of a Quark-Gluon Plasma(QGP) phase in relativistic nuclear collisions.Following the experimental observations on strangeness enhancement in proton-nucleus and nucleus-nucleus collisions at the SPS energies the WA97 has measured a clear enhancement of multi-strange baryons (Λ, Ξ, Ω )with their strange quark content in 158 AGeV/c Pb+Pb collisions relative to p+Pb collisions.

  19. Quantitative properties of clustering within modern microscopic nuclear models

    International Nuclear Information System (INIS)

    Volya, A.; Tchuvil’sky, Yu. M.

    2016-01-01

    A method for studying cluster spectroscopic properties of nuclear fragmentation, such as spectroscopic amplitudes, cluster form factors, and spectroscopic factors, is developed on the basis of modern precision nuclear models that take into account the mixing of large-scale shell-model configurations. Alpha-cluster channels are considered as an example. A mathematical proof of the need for taking into account the channel-wave-function renormalization generated by exchange terms of the antisymmetrization operator (Fliessbach effect) is given. Examples where this effect is confirmed by a high quality of the description of experimental data are presented. By and large, the method in question extends substantially the possibilities for studying clustering phenomena in nuclei and for improving the quality of their description.

  20. Measurement of target fragments produced by 160 MeV proton beam in aluminum and polyethylene with CR-39 plastic nuclear track detectors

    Czech Academy of Sciences Publication Activity Database

    Ambrožová, Iva; Yasuda, N.; Kodaira, S.; Sihver, L.

    2014-01-01

    Roč. 64, MAY (2014), s. 29-34 ISSN 1350-4487 R&D Projects: GA AV ČR KJB100480901; GA AV ČR IAA100480902; GA MŠk LG14004 Institutional support: RVO:61389005 Keywords : target fragments * high-energy protons * Aluminium * Polyethylene * plastic nuclear track detectors * CR-39 Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.213, year: 2014

  1. Percolation Model of Nuclear Multifragmentation in High Energy Nucleus-Nucleus Interactions

    International Nuclear Information System (INIS)

    Abdel-Waged, Kh.

    1994-01-01

    A hybrid model based on Reggeon theory inspired model of nuclear distribution, which was successful in explaining the cascading of particles in high energy nucleus-nucleus interactions, and percolation model is proposed. In the framework of this model the yield of the fragment in p + Ag, Au at 350 GeV and C + Ag, Au at 3.6 GeV/nucleon as well as the charge distribution of fragments in Kr, Xe and U interactions with emulsion at ∼ 1 GeV/nucleon is correctly described. 32 refs., 3 figs

  2. Calculated effects of backscattering on skin dosimetry for nuclear fuel fragments

    International Nuclear Information System (INIS)

    Aydarous, A. Sh

    2008-01-01

    The size of hot particles contained in nuclear fallout ranges from 10 nm to 20 μm for the worldwide weapons fallout. Hot particles from nuclear power reactors can be significantly bigger (100 μm to several millimetres). Electron backscattering from such particles is a prominent secondary effect in beta dosimetry for radiological protection purposes, such as skin dosimetry. In this study, the effect of electron backscattering due to hot particles contamination on skin dose is investigated. These include parameters such as detector area, source radius, source energy, scattering material and source density. The Monte-Carlo Neutron Particle code (MCNP4C) was used to calculate the depth dose distribution for 10 different beta sources and various materials. The backscattering dose factors (BSDF) were then calculated. A significant dependence is shown for the BSDF magnitude upon detector area, source radius and scatterers. It is clearly shown that the BSDF increases with increasing detector area. For high Z scatterers, the BSDF can reach as high as 40 and 100% for sources with radii 0.1 and 0.0001 cm, respectively. The variation of BSDF with source radius, source energy and source density is discussed. (authors)

  3. Study of Particle Production and Nuclear Fragmentation in Collisions of $^{16}$O Beams with Emulsion Nuclei at 13-200 A GeV

    CERN Multimedia

    2002-01-01

    .SK 2\\\\ \\\\ The aim of the experiment is to study, on an event by event basis, multiplicities of produced charged particles, pseudo-rapidity density distributions globally and in selected regions of pseudo-rapidity, density fluctuations, multiplicity and angular distributions of nuclear fragments and recoiling protons (30-400~A~MeV) and cross sections for production and interation of light and medium (Z=2-8) projectile fragments. \\\\ \\\\ The detectors are emulsion chambers as well as conventional emulsion stacks. The emulsion chambers consist of several layers of a plastic substrate, each coated with nuclear emulsion on both sides. Since the best measurement accuracy is obtained for the particles with the smallest emission angles, this design is especially suited for the pseudo-rapidity determination. The emulsion stacks, of both high and low sensitivity, have been exposed in the conventional way, with the beam parallel to the emulsion sheets. These stacks are used to study the fragmentation of the interaction n...

  4. Jaguars on the move: modeling movement to mitigate fragmentation from road expansion in the Mayan Forests

    DEFF Research Database (Denmark)

    Colchero, Fernando; Conde, Dalia Amor; Manterola, Carlos

    2011-01-01

    Road-induced habitat fragmentation is one of the greatest threats to large carnivores. Wildlife passes have been used to reduce fragmentation by mitigating the effects of roads as barriers to animal movement. However, direct observations of animals crossing roads are extremely rare and thus......-telemetry and GPS data to infer the movement behavior of jaguars Panthera onca as a response to vegetation, roads and human population density in the Mayan Forests of Mexico and Guatemala. We used the results of the model to simulate jaguars moving along a road that bisects the major reserve system in the area....... The aim of the simulations was to identify suitable locations for wildlife passes. We found that jaguars move preferentially to undisturbed forests and that females avoid moving close to roads and to areas with even low levels of human occupation. Males also avoid roads, but to a lesser degree, and appear...

  5. Semi-empirical fragmentation model of meteoroid motion and radiation during atmospheric penetration

    Science.gov (United States)

    Revelle, D. O.; Ceplecha, Z.

    2002-11-01

    A semi-empirical fragmentation model (FM) of meteoroid motion, ablation, and radiation including two types of fragmentation is outlined. The FM was applied to observational data (height as function of time and the light curve) of Lost City, Innisfree and Benešov bolides. For the Lost City bolide we were able to fit the FM to the observed height as function of time with ±13 m and to the observed light curve with ±0.17 magnitude. Corresponding numbers for Innisfree are ±25 m and ±0.14 magnitude, and for Benešov ±46 m and ±0.19 magnitude. We also define apparent and intrinsic values of σ, K, and τ. Using older results and our fit of FM to the Lost City bolide we derived corrections to intrinsic luminous efficiencies expressed as functions of velocity, mass, and normalized air density.

  6. Assessing rates of forest change and fragmentation in Alabama, USA, using the vegetation change tracker model

    Science.gov (United States)

    Li, Mingshi; Huang, Chengquan; Zhu, Zhiliang; Shi, Hua; Lu, Heng; Peng, Shikui

    2009-01-01

    Forest change is of great concern for land use decision makers and conservation communities. Quantitative and spatial forest change information is critical for addressing many pressing issues, including global climate change, carbon budgets, and sustainability. In this study, our analysis focuses on the differences in geospatial patterns and their changes between federal forests and nonfederal forests in Alabama over the time period 1987–2005, by interpreting 163 Landsat Thematic Mapper (TM) scenes using a vegetation change tracker (VCT) model. Our analysis revealed that for the most part of 1990 s and between 2000 and 2005, Alabama lost about 2% of its forest on an annual basis due to disturbances, but much of the losses were balanced by forest regeneration from previous disturbances. The disturbance maps revealed that federal forests were reasonably well protected, with the fragmentation remaining relatively stable over time. In contrast, nonfederal forests, which are predominant in area share (about 95%), were heavily disturbed, clearly demonstrating decreasing levels of fragmentation during the time period 1987–1993 giving way to a subsequent accelerating fragmentation during the time period 1994–2005. Additionally, the identification of the statistical relationships between forest fragmentation status and forest loss rate and forest net change rate in relation to land ownership implied the distinct differences in forest cutting rate and cutting patterns between federal forests and nonfederal forests. The forest spatial change information derived from the model has provided valuable insights regarding regional forest management practices and disturbance regimes, which are closely associated with regional economics and environmental concerns.

  7. A Review of Fragmentation Models Relative to Molten UO2 Breakup when Quenched in Sodium Coolant

    International Nuclear Information System (INIS)

    Cronenberg, A.W.; Grolmes, M.A.

    1976-01-01

    An important aspect of the fuel-coolant interaction problem relative to liquid metal fast breeder reactor (LMFBR) safety analysis is the fragmentation of molten oxide fuel during contact with liquid sodium coolant. A proper description of the kinetics of such an event requires an understanding of the breakup process and an estimate of the size and dispersion of such finely divided fuel in coolant. In recent years, considerable interest has centered on the problem of determining the nature of such fragmentation. In this paper, both analytic and experimental studies pertaining to such breakup are reviewed in light of recent developments in the understanding of heat transfer and solidification phenomena during quenching of UO 2 in sodium. A more extensive review of this subject can be found in Ref. 1. In conclusion: As discussed, a number of models have been proposed in an attempt to understand the nature of the UO 2 fragmentation process. The four principle mechanisms considered likely to cause such fragmentation (impact forces, boiling, violent gas release, and shell solidification) have been developed to the point where comparative analysis is possible. In addition, recent developments in the understanding of the physics of oxide fuel behavior in sodium coolant (boiling regime criteria, vapor nucleation theories, and prediction of solidification kinetics enable us to asses whether or not the various model assumptions are realistic. In view of this knowledge the following conclusions are made. For the case of hydrodynamic influence on fragmentation, it can be said that although the disruptive forces of impact and viscous drag may contribute to breakup, their effects are not controlling with respect to high temperature materials, including UO 2 -sodium. With respect to the vapor bubble growth and collapse mechanism it was shown that for sodium quenching, where coolant contact may, be expected (as opposed to water), the thermodynamic work potential of the bubble is

  8. Architectural fragments

    DEFF Research Database (Denmark)

    Bang, Jacob Sebastian

    2018-01-01

    I have created a large collection of plaster models: a collection of Obstructions, errors and opportunities that may develop into architecture. The models are fragments of different complex shapes as well as more simple circular models with different profiling and diameters. In this contect I have....... I try to invent the ways of drawing the models - that decode and unfold them into architectural fragments- into future buildings or constructions in the landscape. [1] Luigi Moretti: Italian architect, 1907 - 1973 [2] Man Ray: American artist, 1890 - 1976. in 2015, I saw the wonderful exhibition...... "Man Ray - Human Equations" at the Glyptotek in Copenhagen, organized by the Philips Collection in Washington D.C. and the Israel Museum in Jerusalem (in 2013). See also: "Man Ray - Human Equations" catalogue published by Hatje Cantz Verlag, Germany, 2014....

  9. Macroscopic model description of heavy-ion induced complex-fragment emission

    International Nuclear Information System (INIS)

    Carjan, N.

    1988-01-01

    The Yukawa-plus-exponential finite-range model and the standard liquid-drop model are shortly reviewed and compared. The dependence of the barrier heights and of the saddle-point shapes on mass-asymmetry and on angular momentum is studied for the compound nuclei 110 Sn, 149 Tb and 194 Hg. The predicted asymmetric-fission barriers, charge yields and total kinetic energies are compared with experimental data obtained from the deexcitation of compound nuclei by complex-fragment emission

  10. A new in silico classification model for ready biodegradability, based on molecular fragments.

    Science.gov (United States)

    Lombardo, Anna; Pizzo, Fabiola; Benfenati, Emilio; Manganaro, Alberto; Ferrari, Thomas; Gini, Giuseppina

    2014-08-01

    Regulations such as the European REACH (Registration, Evaluation, Authorization and restriction of Chemicals) often require chemicals to be evaluated for ready biodegradability, to assess the potential risk for environmental and human health. Because not all chemicals can be tested, there is an increasing demand for tools for quick and inexpensive biodegradability screening, such as computer-based (in silico) theoretical models. We developed an in silico model starting from a dataset of 728 chemicals with ready biodegradability data (MITI-test Ministry of International Trade and Industry). We used the novel software SARpy to automatically extract, through a structural fragmentation process, a set of substructures statistically related to ready biodegradability. Then, we analysed these substructures in order to build some general rules. The model consists of a rule-set made up of the combination of the statistically relevant fragments and of the expert-based rules. The model gives good statistical performance with 92%, 82% and 76% accuracy on the training, test and external set respectively. These results are comparable with other in silico models like BIOWIN developed by the United States Environmental Protection Agency (EPA); moreover this new model includes an easily understandable explanation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Novel fragmentation model for pulverized coal particles gasification in low temperature air thermal plasma

    Directory of Open Access Journals (Sweden)

    Jovanović Rastko D.

    2016-01-01

    Full Text Available New system for start-up and flame support based on coal gasification by low temperature air thermal plasma is planned to supplement current heavy oil system in Serbian thermal power plants in order to decrease air pollutions emission and operational costs. Locally introduced plasma thermal energy heats up and ignites entrained coal particles, thus starting chain process which releases heat energy from gasified coal particles inside burner channel. Important stages during particle combustion, such as particle devolatilisation and char combustion, are described with satisfying accuracy in existing commercial CFD codes that are extensively used as powerful tool for pulverized coal combustion and gasification modeling. However, during plasma coal gasification, high plasma temperature induces strong thermal stresses inside interacting coal particles. These stresses lead to “thermal shock” and extensive particle fragmentation during which coal particles with initial size of 50-100 m disintegrate into fragments of at most 5-10 m. This intensifies volatile release by a factor 3-4 and substantially accelerates the oxidation of combustible matter. Particle fragmentation, due to its small size and thus limited influence on combustion process is commonly neglected in modelling. The main focus of this work is to suggest novel approach to pulverized coal gasification under high temperature conditions and to implement it into commercial comprehensive code ANSYS FLUENT 14.0. Proposed model was validated against experimental data obtained in newly built pilot scale D.C plasma burner test facility. Newly developed model showed very good agreement with experimental results with relative error less than 10%, while the standard built-in gasification model had error up to 25%.

  12. Clusters of DNA damage induced by ionizing radiation: Formation of short DNA fragments. I. Theoretical modeling

    International Nuclear Information System (INIS)

    Holley, W.R.; Chatterjee, A.

    1996-01-01

    We have developed a general theoretical model for the interaction of ionizing radiation with chromatin. Chromatin is modeled as a 30-nm-diameter solenoidal fiber composed of 20 turns of nucleosomes, 6 nucleosomes per turn. Charged-particle tracks are modeled by partitioning the energy deposition between primary track core, resulting from glancing collisions with 100 eV or less per event, and δ rays due to knock-on collisions involving energy transfers > 100 eV. A Monte Carlo simulation incorporates damages due to the following molecular mechanisms: (1) ionization of water molecules leading to the formation of circ OH, circ H, e aq , etc.; circ OH attack on sugar molecules leading to strand breaks; circ OH attack on bases; direct ionization of the sugar molecules leading to strand breaks; direct ionization of the bases. Our calculations predict significant clustering of damage both locally, over regions up to 40 hp and over regions extending to several kilobase pairs. A characteristic feature of the regional damage predicted by our model is the production of short fragments of DNA associated with multiple nearby strand breaks. Such fragments have subsequently been detected experimentally and are reported in an accompanying paper after exposure to both high- and low-LET radiation. The overall measured yields agree well quantitatively with the theoretical predictions. Our theoretical results predict the existence of a strong peak at about 85 bp, which represents the revolution period about the nucleosome. Other peaks at multiples of about 1,000 bp correspond to the periodicity of the particular solenoid model of chromatin used in these calculations. Theoretical results in combination with experimental data on fragmentation spectra may help determine the consensus or average structure of the chromatin fibers in mammalian DNA. 27 refs., 7 figs

  13. The effects of hyaluronan and its fragments on lipid models exposed to UV irradiation.

    Science.gov (United States)

    Trommer, Hagen; Wartewig, Siegfried; Böttcher, Rolf; Pöppl, Andreas; Hoentsch, Joachim; Ozegowski, Jörg H; Neubert, Reinhard H H

    2003-03-26

    The effects of hyaluronan and its degradation products on irradiation-induced lipid peroxidation were investigated. Liposomal skin lipid models with increasing complexity were used. Hyaluronan and its fragments were able to reduce the amount of lipid peroxidation secondary products quantified by the thiobarbituric acid (TBA) assay. The qualitative changes were studied by mass spectrometry. To elucidate the nature of free radical involvement electron paramagnetic resonance (EPR) studies were carried out. The influence of hyaluronan and its fragments on the concentration of hydroxyl radicals generated by the Fenton system was examined using the spin trapping technique. Moreover, the mucopolysaccharide's ability to react with stable radicals was checked. The quantification assay of 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) showed no concentration changes of the stable radical caused by hyaluronan. Hyaluronan was found to exhibit prooxidative effects in the Fenton assay in a concentration dependent manner. A transition metal chelation was proposed as a mechanism of this behavior. Considering human skin and its constant exposure to UV light and oxygen and an increased pool of iron in irradiated skin the administration of hyaluronan or its fragments in cosmetic formulations or sunscreens could be helpful for the protection of the human skin. Copyright 2003 Elsevier Science B.V.

  14. Selecting a Conservation Surrogate Species for Small Fragmented Habitats Using Ecological Niche Modelling

    Directory of Open Access Journals (Sweden)

    K. Anne-Isola Nekaris

    2015-01-01

    Full Text Available Flagship species are traditionally large, charismatic animals used to rally conservation efforts. Accepted flagship definitions suggest they need only fulfil a strategic role, unlike umbrella species that are used to shelter cohabitant taxa. The criteria used to select both flagship and umbrella species may not stand up in the face of dramatic forest loss, where remaining fragments may only contain species that do not suit either set of criteria. The Cinderella species concept covers aesthetically pleasing and overlooked species that fulfil the criteria of flagships or umbrellas. Such species are also more likely to occur in fragmented habitats. We tested Cinderella criteria on mammals in the fragmented forests of the Sri Lankan Wet Zone. We selected taxa that fulfilled both strategic and ecological roles. We created a shortlist of ten species, and from a survey of local perceptions highlighted two finalists. We tested these for umbrella characteristics against the original shortlist, utilizing Maximum Entropy (MaxEnt modelling, and analysed distribution overlap using ArcGIS. The criteria highlighted Loris tardigradus tardigradus and Prionailurus viverrinus as finalists, with the former having highest flagship potential. We suggest Cinderella species can be effective conservation surrogates especially in habitats where traditional flagship species have been extirpated.

  15. Critical assessment of nuclear mass models

    International Nuclear Information System (INIS)

    Moeller, P.; Nix, J.R.

    1992-01-01

    Some of the physical assumptions underlying various nuclear mass models are discussed. The ability of different mass models to predict new masses that were not taken into account when the models were formulated and their parameters determined is analyzed. The models are also compared with respect to their ability to describe nuclear-structure properties in general. The analysis suggests future directions for mass-model development

  16. Peri/nuclear localization of intact insulin-like growth factor binding protein-2 and a distinct carboxyl-terminal IGFBP-2 fragment in vivo

    International Nuclear Information System (INIS)

    Hoeflich, A.; Reisinger, R.; Schuett, B.S.; Elmlinger, M.W.; Russo, V.C.; Vargas, G.A.; Jehle, P.M.; Lahm, H.; Renner-Mueller, I.; Wolf, E.

    2004-01-01

    Insulin-like growth factor binding protein-2 (IGFBP-2) as one of the most important IGFBPs has never been assessed in the intracellular compartment in vivo. Since there is evidence for novel intracellular functions of distinct IGFBPs, we investigated the presence of IGFBP-2 inside the cell. In peri/nuclear fractions of various tissues isolated from IGFBP-2 transgenic and non-transgenic mice we were able to show the presence of intact IGFBP-2. In addition, we demonstrate the presence of a highly conserved carboxyl-terminal IGFBP-2 fragment in the peri/nuclear fraction by using different peptide-induced antibodies. In pancreatic sections, confocal microscopy revealed the presence of IGFBP-2 on the nuclear surface but not within the nucleus. Our findings suggest novel functions of intact IGFBP-2 and IGFBP-2 fragments within the cell

  17. Three-particle forces and nuclear models

    International Nuclear Information System (INIS)

    Krutov, V.A.

    1980-01-01

    Different nuclear models accounting and unaccounting for three-particle internucleon forces (TIF) are reviewed. At present only two nuclear models use manifestly TIP: the Vautherin-Brink-Skyrme (VBS) model and the model proposed by the author of the review and called the semiphenomenological (SP) nuclear model. There is a short discussion of major drawbacks of models unaccounting for TIF: multiparticle shell model, ''superfluid model'', Harty-Fock calculations with two-particle forces, Bruckner-Hartry-Fock calculations, the relativistic self-consistent nuclear model. The VBS and SP models are discussed in detail. It is concluded, that the employment of TIF even in a very simplified form (extremely short-range) puts away a lot of problems characteristic to models limited by two-particle forces (collapse at iteratious in Hartry-Fock, simultaneous fitting of the binding energy of a nucleus and the binding energy of a nucleon, etc.) and makes it possible to obtain in a rather simple way such nuclear characteristics as nuclear binding energy, nuclear mean square root radii, nucleon density of a nucleus

  18. Effects of the fragmentation models on the determination of αsub(S) in e+e- annihilation

    International Nuclear Information System (INIS)

    Lavagne, Y.

    1982-06-01

    Jet phenomenology is presented and quantum chromodynamic notions necessary to this study comprehension are given. Device is described, together with data acquisition and different steps of hadronic event selection. Three jet topology events are selected from presented variables and methods. Two models with different fragmentation processes are used to determine αsub(S). Results for each model are gathered and display the fragmentation process influence on αsub(S) value [fr

  19. The transverse momentum dependence of quark fragmentation functions from cascade models

    International Nuclear Information System (INIS)

    Groot, E.H. de; Engels, J.

    1979-01-01

    A covariant generalization of the onedimensional cascade model for quark fragmentation functions is presented, so as to include the transverse momentum behaviour and the possibility to produce different particles at different vertices along the chain. In the scaling limit the exact solution is given, if the primordial function is of the type αZsup(α-1). T(pT). For the more general case of factorizing primordial functions an analytic expression for the seagull effect is derived, which turns out to be independent of the function T(pT). (orig.) [de

  20. Competition and fragmentation: a simple model generating lognormal-like distributions

    International Nuclear Information System (INIS)

    Schwaemmle, V; Queiros, S M D; Brigatti, E; Tchumatchenko, T

    2009-01-01

    The current distribution of language size in terms of speaker population is generally described using a lognormal distribution. Analyzing the original real data we show how the double-Pareto lognormal distribution can give an alternative fit that indicates the existence of a power law tail. A simple Monte Carlo model is constructed based on the processes of competition and fragmentation. The results reproduce the power law tails of the real distribution well and give better results for a poorly connected topology of interactions.

  1. Relativistic models of nuclear structure

    International Nuclear Information System (INIS)

    Gillet, V.; Kim, E.J.; Cauvin, M.; Kohmura, T.; Ohnaka, S.

    1991-01-01

    The introduction of the relativistic field formalism for the description of nuclear structure has improved our understanding of fundamental nuclear mechanisms such as saturation or many body forces. We discuss some of these progresses, both in the semi-classical mean field approximation and in a quantized meson field approach. (author)

  2. A thermomechanical model for the fragmentation of a liquid metal droplet cooled by water

    Science.gov (United States)

    Ivochkin, Yu P.; Monastyrskiy, V. P.

    2017-11-01

    A thermo mechanical aspect of the fragmentation of a liquid metal droplet, solidified as it falls into cold water, is considered in the presented model. The formation of a solid phase in the form of continuous, fluid-tight and relatively rigid casting skin results in a pressure decrease inside the droplet due to the difference between liquid and solid metal density. Because of the high compression modulus of the melt, the pressure in the droplet becomes negative when the thickness of the solid skin achieves several microns. The tensile stress in the melt results in the deformation of the casting skin or the melt’s continuity violation in the form of a shrinkage pore. The rupture of the deformed solid crust results in the penetration of steam jets into the liquid part of the drop. Due to the difference in pressure in the surrounding steam and in the droplet, the casting skin is crushed and the melt is blown out. Both scenarios contribute to the hydrodynamic destruction of the droplet. The suggested thermo mechanical model gives a qualitative explanation for experimental data. In the experimental part of the work, droplets of molten Sn were solidified in water. The solidified pieces of the droplets usually include deformed, thin-walled shells and dispersed particles. On a qualitative level the composition and shape of the solid fragments can be explained within the bounds of the suggested thermo mechanical model.

  3. Sequential fragmentation of Pleistocene forests in an East Africa biodiversity hotspot: chameleons as a model to track forest history.

    Directory of Open Access Journals (Sweden)

    G John Measey

    Full Text Available The Eastern Arc Mountains (EAM is an example of naturally fragmented tropical forests, which contain one of the highest known concentrations of endemic plants and vertebrates. Numerous paleo-climatic studies have not provided direct evidence for ancient presence of Pleistocene forests, particularly in the regions in which savannah presently occurs. Knowledge of the last period when forests connected EAM would provide a sound basis for hypothesis testing of vicariance and dispersal models of speciation. Dated phylogenies have revealed complex patterns throughout EAM, so we investigated divergence times of forest fauna on four montane isolates in close proximity to determine whether forest break-up was most likely to have been simultaneous or sequential, using population genetics of a forest restricted arboreal chameleon, Kinyongia boehmei.We used mitochondrial and nuclear genetic sequence data and mutation rates from a fossil-calibrated phylogeny to estimate divergence times between montane isolates using a coalescent approach. We found that chameleons on all mountains are most likely to have diverged sequentially within the Pleistocene from 0.93-0.59 Ma (95% HPD 0.22-1.84 Ma. In addition, post-hoc tests on chameleons on the largest montane isolate suggest a population expansion ∼182 Ka.Sequential divergence is most likely to have occurred after the last of three wet periods within the arid Plio-Pleistocene era, but was not correlated with inter-montane distance. We speculate that forest connection persisted due to riparian corridors regardless of proximity, highlighting their importance in the region's historic dispersal events. The population expansion coincides with nearby volcanic activity, which may also explain the relative paucity of the Taita's endemic fauna. Our study shows that forest chameleons are an apposite group to track forest fragmentation, with the inference that forest extended between some EAM during the Pleistocene 1

  4. Dynamical fragmentation of flux tubes in the Friedberg-Lee model

    International Nuclear Information System (INIS)

    Loh, S.; Greiner, C.; Mosel, U.; Thoma, M.H.

    1997-01-01

    We present two novel dynamical features of flux tubes in the Friedberg-Lee model. First the fusion of two (anti-)parallel flux tubes, where we extract a string-string interaction potential which has a qualitative similarity to the nucleon-nucleon potential in the Friedberg-Lee model obtained by Koepf et al. Furthermore we show the dynamical breakup of flux tubes via qq-particle production and the disintegration into mesons. We find, as a shortcoming of the present realization of the model, that the full dynamical transport approach presented in a previous publication fails to provide the disintegration mechanism in the semiclassical limit. Therefore, in addition, we present here a molecular dynamical approach for the motion of the quarks and show, as a first application, the space-time development of the quarks and their mean-fields for Lund-type string fragmentation processes. (orig.)

  5. Ontology aided modeling of organic reaction mechanisms with flexible and fragment based XML markup procedures.

    Science.gov (United States)

    Sankar, Punnaivanam; Aghila, Gnanasekaran

    2007-01-01

    The mechanism models for primary organic reactions encoding the structural fragments undergoing substitution, addition, elimination, and rearrangements are developed. In the proposed models, each and every structural component of mechanistic pathways is represented with flexible and fragment based markup technique in XML syntax. A significant feature of the system is the encoding of the electron movements along with the other components like charges, partial charges, half bonded species, lone pair electrons, free radicals, reaction arrows, etc. needed for a complete representation of reaction mechanism. The rendering of reaction schemes described with the proposed methodology is achieved with a concise XML extension language interoperating with the structure markup. The reaction scheme is visualized as 2D graphics in a browser by converting them into SVG documents enabling the desired layouts normally perceived by the chemists conventionally. An automatic representation of the complex patterns of the reaction mechanism is achieved by reusing the knowledge in chemical ontologies and developing artificial intelligence components in terms of axioms.

  6. The nuclear reaction model code MEDICUS

    International Nuclear Information System (INIS)

    Ibishia, A.I.

    2008-01-01

    The new computer code MEDICUS has been used to calculate cross sections of nuclear reactions. The code, implemented in MATLAB 6.5, Mathematica 5, and Fortran 95 programming languages, can be run in graphical and command line mode. Graphical User Interface (GUI) has been built that allows the user to perform calculations and to plot results just by mouse clicking. The MS Windows XP and Red Hat Linux platforms are supported. MEDICUS is a modern nuclear reaction code that can compute charged particle-, photon-, and neutron-induced reactions in the energy range from thresholds to about 200 MeV. The calculation of the cross sections of nuclear reactions are done in the framework of the Exact Many-Body Nuclear Cluster Model (EMBNCM), Direct Nuclear Reactions, Pre-equilibrium Reactions, Optical Model, DWBA, and Exciton Model with Cluster Emission. The code can be used also for the calculation of nuclear cluster structure of nuclei. We have calculated nuclear cluster models for some nuclei such as 177 Lu, 90 Y, and 27 Al. It has been found that nucleus 27 Al can be represented through the two different nuclear cluster models: 25 Mg + d and 24 Na + 3 He. Cross sections in function of energy for the reaction 27 Al( 3 He,x) 22 Na, established as a production method of 22 Na, are calculated by the code MEDICUS. Theoretical calculations of cross sections are in good agreement with experimental results. Reaction mechanisms are taken into account. (author)

  7. A vapour bubble collapse model to describe the fragmentation of low-melting materials

    International Nuclear Information System (INIS)

    Benz, R.; Schober, P.

    1977-11-01

    By means of a model, the fragmentation of a hot melt of metal in consequence of collapsing vapour-bubbles is investigated. In particular the paper deals with the development of the physical model-ideas for calculation of the temperature of contact that adjusts between the temperature of the melt and the coolant, of the waiting-time until bubble-nucleation occurs and of the maximal obtainable vapour-bubble-radius in dependence of the coolant-temperature. After that follows the description of the computing-program belonging to this model and of the results of an extensive parameter-study. The study examined the influence of the temperature of melt and coolant, the melted mass, the nucleation-site-density, the average maximum bubble-radius, the duration of film-breakdown and the coefficient of heat-transition. The calculation of the process of fragmentation turns out to be according to expectation, whereas the duration of this process seems to be somewhat too long. The dependence of the surface-enlargement on the subcooling of the water-bath and the initial temperature of the melt is not yet reproduced satisfactorily by the model. The reasons for this are the temperature-increase of the water-bath as well as the fact that the coupling of heat-flux-density and nucleation-site-density are not taken into consideration. Further improvement of the model is necessary and may improve the results in the sense of the experimental observations. (orig.) [de

  8. Modeling the integration of bacterial rRNA fragments into the human cancer genome.

    Science.gov (United States)

    Sieber, Karsten B; Gajer, Pawel; Dunning Hotopp, Julie C

    2016-03-21

    Cancer is a disease driven by the accumulation of genomic alterations, including the integration of exogenous DNA into the human somatic genome. We previously identified in silico evidence of DNA fragments from a Pseudomonas-like bacteria integrating into the 5'-UTR of four proto-oncogenes in stomach cancer sequencing data. The functional and biological consequences of these bacterial DNA integrations remain unknown. Modeling of these integrations suggests that the previously identified sequences cover most of the sequence flanking the junction between the bacterial and human DNA. Further examination of these reads reveals that these integrations are rich in guanine nucleotides and the integrated bacterial DNA may have complex transcript secondary structures. The models presented here lay the foundation for future experiments to test if bacterial DNA integrations alter the transcription of the human genes.

  9. A hidden Markov model to assess drug-induced sleep fragmentation in the telemetered rat.

    Science.gov (United States)

    Diack, C; Ackaert, O; Ploeger, B A; van der Graaf, P H; Gurrell, R; Ivarsson, M; Fairman, D

    2011-12-01

    Drug-induced sleep fragmentation can cause sleep disturbances either via their intended pharmacological action or as a side effect. Examples of disturbances include excessive daytime sleepiness, insomnia and nightmares. Developing drugs without these side effects requires insight into the mechanisms leading to sleep disturbance. The characterization of the circadian sleep pattern by EEG following drug exposure has improved our understanding of these mechanisms and their translatability across species. The EEG shows frequent transitions between specific sleep states leading to multiple correlated sojourns in these states. We have developed a Markov model to consider the high correlation in the data and quantitatively compared sleep disturbance in telemetered rats induced by methylphenidate, which is known to disturb sleep, and of a new chemical entity (NCE). It was assumed that these drugs could either accelerate or decelerate the transitions between the sleep states. The difference in sleep disturbance of methylphenidate and the NCE were quantitated and different mechanisms of action on rebound sleep were identified. The estimated effect showed that both compounds induce sleep fragmentation with methylphenidate being fivefold more potent compared to the NCE.

  10. Nuclear isomerism in fission fragments produced by the spontaneous fission of {sup 252}Cf; Isomerisme nucleaire dans les fragments de fission produits dans la fission spontanee du {sup 252}Cf

    Energy Technology Data Exchange (ETDEWEB)

    Gautherin, C

    1997-09-01

    This thesis is devoted to the study of the nuclear structure of neutron-rich nuclei, via the search of isomeric nuclear states. Neutron-rich nuclei were produced in the spontaneous fission of {sup 252}Cf. The experimental study of isomeric states in these nuclei was performed with the {gamma}-array EUROGAM II, coupled to an additional and original fission fragment detector composed by photovoltaic cells, SAPhIR. The photovoltaic cells are well adapted to detect low energy heavy ions and have good energy and time resolutions to obtain a good fission fragment detection. This experiment led to the discovery of new isomeric states in {sup 135}Xe, {sup 104}Mo, {sup 146,147,148}Ce and {sup 152,154,156}Nd, with lifetimes between 60 ns and 2 {mu}s. Level schemes of these nuclei have been completed. An interpretation of the isomeric states in the nuclei {sup 154,156}Nd and {sup 156,158}Sm was performed by Hartree-Fock-Bogolyubov calculations using the DIS Gogny force with two quasi-particles excitations. The confrontation with the experimental results led to an interpretation of these isomeric states as K-isomers. (author)

  11. Model of cooling nuclear fuel rod in the nuclear reactor

    International Nuclear Information System (INIS)

    Lavicka, David; Polansky, Jiri

    2010-01-01

    The following topics are described: Some basic requirements for nuclear fuel rods; The VVER 1000 fuel rod; Classification of the two-phase flow in the vertical tube; Type of heat transfer crisis in the vertical tube; Experimental apparatus; Model of the nuclear fuel rod and spacers; Potential of the experimental apparatus (velocity profile measurement via PIV; thermal flow field measurement by the PLIF method; cooling graph in dependence on the fuel rod temperature; comparison of the hydrodynamic properties with respect to the design features of the spacers). (P.A.)

  12. Fragmentation approach to the point-island model with hindered aggregation: Accessing the barrier energy

    Science.gov (United States)

    González, Diego Luis; Pimpinelli, Alberto; Einstein, T. L.

    2017-07-01

    We study the effect of hindered aggregation on the island formation process in a one- (1D) and two-dimensional (2D) point-island model for epitaxial growth with arbitrary critical nucleus size i . In our model, the attachment of monomers to preexisting islands is hindered by an additional attachment barrier, characterized by length la. For la=0 the islands behave as perfect sinks while for la→∞ they behave as reflecting boundaries. For intermediate values of la, the system exhibits a crossover between two different kinds of processes, diffusion-limited aggregation and attachment-limited aggregation. We calculate the growth exponents of the density of islands and monomers for the low coverage and aggregation regimes. The capture-zone (CZ) distributions are also calculated for different values of i and la. In order to obtain a good spatial description of the nucleation process, we propose a fragmentation model, which is based on an approximate description of nucleation inside of the gaps for 1D and the CZs for 2D. In both cases, the nucleation is described by using two different physically rooted probabilities, which are related with the microscopic parameters of the model (i and la). We test our analytical model with extensive numerical simulations and previously established results. The proposed model describes excellently the statistical behavior of the system for arbitrary values of la and i =1 , 2, and 3.

  13. Safety Cultural Competency Modeling in Nuclear Organizations

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sa Kil; Oh, Yeon Ju; Luo, Meiling; Lee, Yong Hee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    The nuclear safety cultural competency model should be supplemented through a bottom-up approach such as behavioral event interview. The developed model, however, is meaningful for determining what should be dealt for enhancing safety cultural competency of nuclear organizations. The more details of the developing process, results, and applications will be introduced later. Organizational culture include safety culture in terms of its organizational characteristics.

  14. Nuclear fuel: modelling the advanced plutonium assembly

    International Nuclear Information System (INIS)

    Kaoua, Th.; Lenain, R.

    2004-01-01

    The benefits of modeling in the nuclear sector are illustrated by the example of the design study for a new plutonium fuel assembly, APA, capable of ensuring maximum consumption of this fuel in pressurized-water reactors. Beyond the physical design of the assembly and its integration into the reactor, this serves for the working out of a complete materials flow and assists in modeling production from the entire inventory of nuclear power stations. (authors)

  15. Nuclear fuel: modelling the advanced plutonium assembly

    International Nuclear Information System (INIS)

    N'kaoua, Th.; Lenain, R.

    2002-01-01

    The benefits of modeling in the nuclear sector are illustrated by the example of the design study for a new plutonium fuel assembly, APA, capable of ensuring maximum consumption of this fuel in pressurized-water reactors. Beyond the physical design of the assembly and its integration into the reactor, this serves for the working out of a complete materials flow and assists in modeling production from the entire inventory of nuclear power stations. (authors)

  16. The new business model for nuclear

    International Nuclear Information System (INIS)

    Galange, D.

    2006-01-01

    New nuclear development will require new business models that ensure maximum risk mitigation for the plant owner and rate payers. To deliver this model, AECL has joined with leading members of the nuclear industry to form Team CANDU. This presentation will introduce contracting structures that have been used by Team CANDU members to reduce plant delivery risk in an ongoing record of successful project completions over the last decade. (author)

  17. Nuclear clustering - a cluster core model study

    International Nuclear Information System (INIS)

    Paul Selvi, G.; Nandhini, N.; Balasubramaniam, M.

    2015-01-01

    Nuclear clustering, similar to other clustering phenomenon in nature is a much warranted study, since it would help us in understanding the nature of binding of the nucleons inside the nucleus, closed shell behaviour when the system is highly deformed, dynamics and structure at extremes. Several models account for the clustering phenomenon of nuclei. We present in this work, a cluster core model study of nuclear clustering in light mass nuclei

  18. Anti-coagulation effect of Fc fragment against anti-β2-GP1 antibodies in mouse models with APS.

    Science.gov (United States)

    Xie, Weidong; Zhang, Yaou; Bu, Cunya; Sun, Shijing; Hu, Shaoliang; Cai, Guoping

    2011-01-01

    Anti-beta (2)-glycoprotein I (anti-β2-GP1) is one of the important pathogenesis factors responsible for thrombosis formation in patients with antiphospholipid syndrome (APS). Administration of intravenous immunoglobulin (IVIg) is a common method used to inhibit the abnormal antibody levels and decrease the mortality of APS in emergency situations. We hypothesize that the Fc fragment of IgG is the molecular structure responsible for these effects. The present study investigates the beneficial effects of both recombinant and natural human Fc fragments of heterogeneous IgG against human anti-β2-GP1 antibodies in mouse models with APS. Results showed that both recombinant and natural human Fc fragments moderately but significantly decreased the levels of serum anti-β2-GP1 antibodies and had anti-coagulation effects in human β2-GP1-immunized mice. Furthermore, both recombinant and natural human Fc fragments inhibited thrombosis formation and decreased mortality in mouse models infused intravenously with human anti-β2GP1 antibodies from patients with APS. Findings suggest that the Fc fragment might be one of the active structural units of heterogeneous IgG. Thus, recombinant human Fc fragment administration may be a useful treatment for individuals with APS. Copyright © 2010 Elsevier B.V. All rights reserved.

  19. Dynamic modelling of nuclear steam generators

    International Nuclear Information System (INIS)

    Kerlin, T.W.; Katz, E.M.; Freels, J.; Thakkar, J.

    1980-01-01

    Moving boundary, nodal models with dynamic energy balances, dynamic mass balances, quasi-static momentum balances, and an equivalent single channel approach have been developed for steam generators used in nuclear power plants. The model for the U-tube recirculation type steam generator is described and comparisons are made of responses from models of different complexity; non-linear versus linear, high-order versus low order, detailed modeling of the control system versus a simple control assumption. The results of dynamic tests on nuclear power systems show that when this steam generator model is included in a system simulation there is good agreement with actual plant performance. (author)

  20. Modeling news dissemination on nuclear issues

    Energy Technology Data Exchange (ETDEWEB)

    Reis Junior, Jose S.B.; Barroso, Antonio C.O.; Menezes, Mario O., E-mail: jsbrj@ime.usp.b, E-mail: barroso@ipen.b, E-mail: mario@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Using a modified epidemiological model, the dissemination of news by media agents after the occurrence of large scale disasters was studied. A modified compartmented model was developed in a previous paper presented at INAC 2007. There it used to study to the Chernobyl's nuclear accident (1986) and the Concorde airplane crash (2000). Now the model has been applied to a larger and more diverse group of events - nuclear, non-nuclear and naturally caused disasters. To be comprehensive, old and recent events from various regions of the world were selected. A more robust news repository was used, and improved search techniques were developed to ensure that the scripts would not count false positive news. The same model was used but with improved non-linear embedded simulation optimization algorithms to generate the parameters of interest for our model. Individual parameters and some specific combination of them allow some interesting perceptions on how the nature of the accident / disaster gives rise to different profiles of growth and decay of the news. In our studies events involving nuclear causes generate news repercussion with more explosive / robust surge profiles and longer decaying tails than those of other natures. As a consequence of these differences, public opinion and policy makers are also much more sensitive to some issues than to others. The model, through its epidemiological parameters, shows in quantitative manner how 'nervous' the media content generators are with respect to nuclear installations and how resilient this negative feelings about nuclear is. (author)

  1. Modeling news dissemination on nuclear issues

    International Nuclear Information System (INIS)

    Reis Junior, Jose S.B.; Barroso, Antonio C.O.; Menezes, Mario O.

    2011-01-01

    Using a modified epidemiological model, the dissemination of news by media agents after the occurrence of large scale disasters was studied. A modified compartmented model was developed in a previous paper presented at INAC 2007. There it used to study to the Chernobyl's nuclear accident (1986) and the Concorde airplane crash (2000). Now the model has been applied to a larger and more diverse group of events - nuclear, non-nuclear and naturally caused disasters. To be comprehensive, old and recent events from various regions of the world were selected. A more robust news repository was used, and improved search techniques were developed to ensure that the scripts would not count false positive news. The same model was used but with improved non-linear embedded simulation optimization algorithms to generate the parameters of interest for our model. Individual parameters and some specific combination of them allow some interesting perceptions on how the nature of the accident / disaster gives rise to different profiles of growth and decay of the news. In our studies events involving nuclear causes generate news repercussion with more explosive / robust surge profiles and longer decaying tails than those of other natures. As a consequence of these differences, public opinion and policy makers are also much more sensitive to some issues than to others. The model, through its epidemiological parameters, shows in quantitative manner how 'nervous' the media content generators are with respect to nuclear installations and how resilient this negative feelings about nuclear is. (author)

  2. Large Time Asymptotics for a Continuous Coagulation-Fragmentation Model with Degenerate Size-Dependent Diffusion

    KAUST Repository

    Desvillettes, Laurent

    2010-01-01

    We study a continuous coagulation-fragmentation model with constant kernels for reacting polymers (see [M. Aizenman and T. Bak, Comm. Math. Phys., 65 (1979), pp. 203-230]). The polymers are set to diffuse within a smooth bounded one-dimensional domain with no-flux boundary conditions. In particular, we consider size-dependent diffusion coefficients, which may degenerate for small and large cluster-sizes. We prove that the entropy-entropy dissipation method applies directly in this inhomogeneous setting. We first show the necessary basic a priori estimates in dimension one, and second we show faster-than-polynomial convergence toward global equilibria for diffusion coefficients which vanish not faster than linearly for large sizes. This extends the previous results of [J.A. Carrillo, L. Desvillettes, and K. Fellner, Comm. Math. Phys., 278 (2008), pp. 433-451], which assumes that the diffusion coefficients are bounded below. © 2009 Society for Industrial and Applied Mathematics.

  3. World Integrated Nuclear Evaluation System: Model documentation

    International Nuclear Information System (INIS)

    1991-12-01

    The World Integrated Nuclear Evaluation System (WINES) is an aggregate demand-based partial equilibrium model used by the Energy Information Administration (EIA) to project long-term domestic and international nuclear energy requirements. WINES follows a top-down approach in which economic growth rates, delivered energy demand growth rates, and electricity demand are projected successively to ultimately forecast total nuclear generation and nuclear capacity. WINES could be potentially used to produce forecasts for any country or region in the world. Presently, WINES is being used to generate long-term forecasts for the United States, and for all countries with commercial nuclear programs in the world, excluding countries located in centrally planned economic areas. Projections for the United States are developed for the period from 2010 through 2030, and for other countries for the period starting in 2000 or 2005 (depending on the country) through 2010. EIA uses a pipeline approach to project nuclear capacity for the period between 1990 and the starting year for which the WINES model is used. This approach involves a detailed accounting of existing nuclear generating units and units under construction, their capacities, their actual or estimated time of completion, and the estimated date of retirements. Further detail on this approach can be found in Appendix B of Commercial Nuclear Power 1991: Prospects for the United States and the World

  4. Population viability analysis: using a modeling tool to assess the viability of tapir populations in fragmented landscapes.

    Science.gov (United States)

    Medici, Emília Patrícia; Desbiez, Arnaud Leonard Jean

    2012-12-01

    A population viability analysis (PVA) was conducted of the lowland tapir populations in the Atlantic Forest of the Pontal do Paranapanema region, Brazil, including Morro do Diabo State Park (MDSP) and surrounding forest fragments. Results from the model projected that the population of 126 tapirs in MDSP is likely to persist over the next 100 years; however, 200 tapirs would be required to maintain a viable population. Sensitivity analysis showed that sub-adult mortality and adult mortality have the strongest influence on the dynamics of lowland tapir populations. High road-kill has a major impact on the MDSP tapir population and can lead to population extinction. Metapopulation modeling showed that dispersal of tapirs from MDSP to the surrounding fragments can be detrimental to the overall metapopulation, as fragments act as sinks. Nevertheless, the model showed that under certain conditions the maintenance of the metapopulation dynamics might be determinant for the persistence of tapirs in the region, particularly in the smaller fragments. The establishment of corridors connecting MDSP to the forest fragments models resulted in an increase in the stochastic growth rate, making tapirs more resilient to threats and catastrophes, but only if rates of mortality were not increased when using corridors. The PVA showed that the conservation of tapirs in the Pontal region depends on: the effective protection of MDSP; maintenance and, whenever possible, enhancement of the functional connectivity of the landscape, reducing mortality during dispersal and threats in the unprotected forest fragments; and neutralization of all threats affecting tapirs in the smaller forest fragments. © 2012 Wiley Publishing Asia Pty Ltd, ISZS and IOZ/CAS.

  5. International Nuclear Model. Volume 3. Program description

    International Nuclear Information System (INIS)

    Andress, D.

    1985-01-01

    This is Volume 3 of three volumes of documentation of the International Nuclear Model (INM). This volume presents the Program Description of the International Nuclear Model, which was developed for the Nuclear and Alternate Fuels Division (NAFD), Office of Coal, Nuclear, Electric and Alternate Fuels, Energy Information Administration (EIA), US Department of Energy (DOE). The International Nuclear Model (INM) is a comprehensive model of the commercial nuclear power industry. It simulates economic decisions for reactor deployment and fuel management decision based on an input set of technical economic and scenario parameters. The technical parameters include reactor operating characteristics, fuel cycle timing and mass loss factors, and enrichment tails assays. Economic parameters include fuel cycle costs, financial data, and tax alternatives. INM has a broad range of scenario options covering, for example, process constraints, interregional activities, reprocessing, and fuel management selection. INM reports reactor deployment schedules, electricity generation, and fuel cycle requirements and costs. It also has specialized reports for extended burnup and permanent disposal. Companion volumes to Volume 3 are: Volume 1 - Model Overview, and Volume 2 - Data Base Relationships

  6. Complex fragments from excited actinide nuclei. A new test of the finite range model

    International Nuclear Information System (INIS)

    Sarantities, D.G.; Bowman, D.R.; Wozniak, G.J.; Charity, R.J.; Liu, Z.H.; McDonald, R.J.; McMahan, M.A.; Moretto, L.G.

    1989-01-01

    Complex fragments ranging in charge from 7 ≤ Z ≤ 45 have been detected in binary coincidence following the reaction of 8.4 MeV/u 232 Th+ 12 C, and are shown to arise from the binary decay of a 244 Cm compound nucleus. This work confirms earlier radiochemical observations of very light fragments in the fission fragment mass distribution, establishes their binary character, and interprets their yield in terms of finite range potential energy barriers. (orig.)

  7. Complex fragments from excited actinide nuclei: A new test of the finite range model

    International Nuclear Information System (INIS)

    Sarantities, D.G.; Bowman, D.R.; Wozniak, G.J.; Charity, R.J.; Liu, Z.H.; McDonald, R.J.; McMahan, M.A.; Moretto, L.G.

    1988-05-01

    Complex fragments ranging in charge from 7≤Z≤45 have been detected in binary coincidence following the reaction of 8.4 MeV/u 232 Th+ 12 C, and are shown to arise from the binary decay of a 244 Cm compound nucleus. This work confirms earlier radiochemical observations of very light fragments in the fission fragment mass distribution, establishes their binary character, and interprets their yield in terms of finite range potential energy barriers. 15 refs., 3 figs

  8. Global nuclear material flow/control model

    International Nuclear Information System (INIS)

    Dreicer, J.S.; Rutherford, D.S.; Fasel, P.K.; Riese, J.M.

    1997-01-01

    This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The nuclear danger can be reduced by a system for global management, protection, control, and accounting as part of an international regime for nuclear materials. The development of an international fissile material management and control regime requires conceptual research supported by an analytical and modeling tool which treats the nuclear fuel cycle as a complete system. The prototype model developed visually represents the fundamental data, information, and capabilities related to the nuclear fuel cycle in a framework supportive of national or an international perspective. This includes an assessment of the global distribution of military and civilian fissile material inventories, a representation of the proliferation pertinent physical processes, facility specific geographic identification, and the capability to estimate resource requirements for the management and control of nuclear material. The model establishes the foundation for evaluating the global production, disposition, and safeguards and security requirements for fissile nuclear material and supports the development of other pertinent algorithmic capabilities necessary to undertake further global nuclear material related studies

  9. Sensitivity study of experimental measures for the nuclear liquid-gas phase transition in the statistical multifragmentation model

    Science.gov (United States)

    Lin, W.; Ren, P.; Zheng, H.; Liu, X.; Huang, M.; Wada, R.; Qu, G.

    2018-05-01

    The experimental measures of the multiplicity derivatives—the moment parameters, the bimodal parameter, the fluctuation of maximum fragment charge number (normalized variance of Zmax, or NVZ), the Fisher exponent (τ ), and the Zipf law parameter (ξ )—are examined to search for the liquid-gas phase transition in nuclear multifragmention processes within the framework of the statistical multifragmentation model (SMM). The sensitivities of these measures are studied. All these measures predict a critical signature at or near to the critical point both for the primary and secondary fragments. Among these measures, the total multiplicity derivative and the NVZ provide accurate measures for the critical point from the final cold fragments as well as the primary fragments. The present study will provide a guide for future experiments and analyses in the study of the nuclear liquid-gas phase transition.

  10. Bond graph modeling of nuclear reactor dynamics

    International Nuclear Information System (INIS)

    Tylee, J.L.

    1981-01-01

    A tenth-order linear model of a pressurized water reactor (PWR) is developed using bond graph techniques. The model describes the nuclear heat generation process and the transfer of this heat to the reactor coolant. Comparisons between the calculated model response and test data from a small-scale PWR show the model to be an adequate representation of the actual plant dynamics. Possible application of the model in an advanced plant diagnostic system is discussed

  11. Universal elements of fragmentation

    International Nuclear Information System (INIS)

    Yanovsky, V. V.; Tur, A. V.; Kuklina, O. V.

    2010-01-01

    A fragmentation theory is proposed that explains the universal asymptotic behavior of the fragment-size distribution in the large-size range, based on simple physical principles. The basic principles of the theory are the total mass conservation in a fragmentation process and a balance condition for the energy expended in increasing the surface of fragments during their breakup. A flux-based approach is used that makes it possible to supplement the basic principles and develop a minimal theory of fragmentation. Such a supplementary principle is that of decreasing fragment-volume flux with increasing energy expended in fragmentation. It is shown that the behavior of the decreasing flux is directly related to the form of a power-law fragment-size distribution. The minimal theory is used to find universal asymptotic fragment-size distributions and to develop a natural physical classification of fragmentation models. A more general, nonlinear theory of strong fragmentation is also developed. It is demonstrated that solutions to a nonlinear kinetic equation consistent with both basic principles approach a universal asymptotic size distribution. Agreement between the predicted asymptotic fragment-size distributions and experimental observations is discussed.

  12. An improved algorithm for MFR fragment assembly

    International Nuclear Information System (INIS)

    Kontaxis, Georg

    2012-01-01

    A method for generating protein backbone models from backbone only NMR data is presented, which is based on molecular fragment replacement (MFR). In a first step, the PDB database is mined for homologous peptide fragments using experimental backbone-only data i.e. backbone chemical shifts (CS) and residual dipolar couplings (RDC). Second, this fragment library is refined against the experimental restraints. Finally, the fragments are assembled into a protein backbone fold using a rigid body docking algorithm using the RDCs as restraints. For improved performance, backbone nuclear Overhauser effects (NOEs) may be included at that stage. Compared to previous implementations of MFR-derived structure determination protocols this model-building algorithm offers improved stability and reliability. Furthermore, relative to CS-ROSETTA based methods, it provides faster performance and straightforward implementation with the option to easily include further types of restraints and additional energy terms.

  13. Material effect in the nuclear fuel-coolant interaction: Analyses of prototypic melt fragmentation and solidification in the KROTOS facility

    Czech Academy of Sciences Publication Activity Database

    Tyrpekl, V.; Piluso, P.; Bakardjieva, Snejana; Dugne, O.

    2014-01-01

    Roč. 186, č. 2 (2014), s. 229-240 ISSN 0029-5450 Institutional support: RVO:61388980 Keywords : fuel-coolant interaction * melt fragmentation * KROTOS facility Subject RIV: CA - Inorganic Chemistry Impact factor: 0.725, year: 2014

  14. Thermodynamics of the fuel fragmentation gas

    International Nuclear Information System (INIS)

    Perez, R.B.; Alsmiller, R.G. Jr.

    1977-01-01

    In the context of nuclear reactor safety studies, a program is in progress at ORNL whereby fuel-fragmentation situations are mocked up by the application of high-current capacitor discharges through solid UO 2 samples. The goal of the present work is to predict such quantities as the number of gas and liquid fragments and their energy distributions. The point of view adopted is that upon fragmentation, a cloud of UO 2 vapor is formed containing ''primeval'' liquid fragments which act as condensation centers. In the evolution of time, fragment growth is controlled by nucleation, coagulation and evaporation processes. Eventually, the vapor-droplet system will reach a situation in which clusters (fragments) of various sizes and UO 2 vapor will coexist in an ''association-disassociation'' equilibrium. Thus, the physical model considered here consists of the identification of the fragmentation gas with an ''imperfect'' vapor, made up of interacting UO 2 vapor and liquid fragments. The results of the study are presented

  15. Habitat fragmentation, vole population fluctuations, and the ROMPA hypothesis: An experimental test using model landscapes.

    Science.gov (United States)

    Batzli, George O

    2016-11-01

    Increased habitat fragmentation leads to smaller size of habitat patches and to greater distance between patches. The ROMPA hypothesis (ratio of optimal to marginal patch area) uniquely links vole population fluctuations to the composition of the landscape. It states that as ROMPA decreases (fragmentation increases), vole population fluctuations will increase (including the tendency to display multi-annual cycles in abundance) because decreased proportions of optimal habitat result in greater population declines and longer recovery time after a harsh season. To date, only comparative observations in the field have supported the hypothesis. This paper reports the results of the first experimental test. I used prairie voles, Microtus ochrogaster, and mowed grassland to create model landscapes with 3 levels of ROMPA (high with 25% mowed, medium with 50% mowed and low with 75% mowed). As ROMPA decreased, distances between patches of favorable habitat (high cover) increased owing to a greater proportion of unfavorable (mowed) habitat. Results from the first year with intensive live trapping indicated that the preconditions for operation of the hypothesis existed (inversely density dependent emigration and, as ROMPA decreased, increased per capita mortality and decreased per capita movement between optimal patches). Nevertheless, contrary to the prediction of the hypothesis that populations in landscapes with high ROMPA should have the lowest variability, 5 years of trapping indicated that variability was lowest with medium ROMPA. The design of field experiments may never be perfect, but these results indicate that the ROMPA hypothesis needs further rigorous testing. © 2016 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

  16. Average Nuclear properties based on statistical model

    International Nuclear Information System (INIS)

    El-Jaick, L.J.

    1974-01-01

    The rough properties of nuclei were investigated by statistical model, in systems with the same and different number of protons and neutrons, separately, considering the Coulomb energy in the last system. Some average nuclear properties were calculated based on the energy density of nuclear matter, from Weizsscker-Beth mass semiempiric formulae, generalized for compressible nuclei. In the study of a s surface energy coefficient, the great influence exercised by Coulomb energy and nuclear compressibility was verified. For a good adjust of beta stability lines and mass excess, the surface symmetry energy were established. (M.C.K.) [pt

  17. Studies of complex fragment emission in heavy ion reactions

    International Nuclear Information System (INIS)

    Sobotka, L.G.

    1989-01-01

    The production of large fragments, fragments with mass between light particles and fission fragments, in intermediate and high energy nuclear reactions has fostered the proposal of a number of novel reaction mechanisms. These include liquid-vapor equilibrium and nuclear shattering. Temporarily left in the wake of these exciting proposed mechanisms was the old standard, statistical decay of compound nuclei. To be sure, the standard treatment of compound nucleus decay did not deal with large fragment production. However, this omission was not due to any fundamental deficiency of statistical models, but rather an uncertainty concerning exactly how to splice large fragment emission into statistical models. A large portion of our program deals with this problem. Specifically, by studying the yields of large fragments produced in sufficiently low energy reactions we are attempting to deduce the asymmetry and l-wave dependence of large fragment emission from compound nuclear intermediates. This, however, is only half of the problem. Since the novel mechanisms proposed for large fragment emission were spawned by intermediate and high energy reaction data, we must also realize the relevance of the compound nucleus mechanisms at high energies. It is not unreasonable to suspect that compound nucleus-like objects are formed with less than complete momentum transfer and perhaps less than complete mass transfer. Therefore the study of energy, mass, and angular momentum transfer in incomplete fusion and non-compound reactions. This thread joins the apparently divergent subjects covered in this report

  18. Nuclear reaction models - source term estimation for safety design in accelerators

    International Nuclear Information System (INIS)

    Nandy, Maitreyee

    2013-01-01

    Accelerator driven subcritical system (ADSS) employs proton induced spallation reaction at a few GeV. Safety design of these systems involves source term estimation in two steps - multiple fragmentation of the target and n+γ emission through a fast process followed by statistical decay of the primary fragments. The prompt radiation field is estimated in the framework of quantum molecular dynamics (QMD) theory, intra-nuclear cascade or Monte Carlo calculations. A few nuclear reaction model codes used for this purpose are QMD, JQMD, Bertini, INCL4, PHITS, followed by statistical decay codes like ABLA, GEM, GEMINI, etc. In the case of electron accelerators photons and photoneutrons dominate the prompt radiation field. High energy photon yield through Bremsstrahlung is estimated in the framework of Born approximation while photoneutron production is calculated using giant dipole resonance and quasi-deuteron formation cross section. In this talk hybrid and exciton PEQ models and QMD formalism will be discussed briefly

  19. Modeling the Nuclear Fuel Cycle

    International Nuclear Information System (INIS)

    Jacobson, Jacob J.; Dunzik-Gougar, Mary Lou; Juchau, Christopher A.

    2010-01-01

    A review of existing nuclear fuel cycle systems analysis codes was performed to determine if any existing codes meet technical and functional requirements defined for a U.S. national program supporting the global and domestic assessment, development and deployment of nuclear energy systems. The program would be implemented using an interconnected architecture of different codes ranging from the fuel cycle analysis code, which is the subject of the review, to fundamental physical and mechanistic codes. Four main functions are defined for the code: (1) the ability to characterize and deploy individual fuel cycle facilities and reactors in a simulation, while discretely tracking material movements, (2) the capability to perform an uncertainty analysis for each element of the fuel cycle and an aggregate uncertainty analysis, (3) the inclusion of an optimization engine able to optimize simultaneously across multiple objective functions, and (4) open and accessible code software and documentation to aid in collaboration between multiple entities and facilitate software updates. Existing codes, categorized as annualized or discrete fuel tracking codes, were assessed according to the four functions and associated requirements. These codes were developed by various government, education and industrial entities to fulfill particular needs. In some cases, decisions were made during code development to limit the level of detail included in a code to ease its use or to focus on certain aspects of a fuel cycle to address specific questions. The review revealed that while no two of the codes are identical, they all perform many of the same basic functions. No code was able to perform defined function 2 or several requirements of functions 1 and 3. Based on this review, it was concluded that the functions and requirements will be met only with development of a new code, referred to as GENIUS.

  20. Uranium Dioxides and Debris Fragments Released to the Environment with Cesium-Rich Microparticles from the Fukushima Daiichi Nuclear Power Plant.

    Science.gov (United States)

    Ochiai, Asumi; Imoto, Junpei; Suetake, Mizuki; Komiya, Tatsuki; Furuki, Genki; Ikehara, Ryohei; Yamasaki, Shinya; Law, Gareth T W; Ohnuki, Toshihiko; Grambow, Bernd; Ewing, Rodney C; Utsunomiya, Satoshi

    2018-03-06

    Trace U was released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) during the meltdowns, but the speciation of the released components of the nuclear fuel remains unknown. We report, for the first time, the atomic-scale characteristics of nanofragments of the nuclear fuels that were released from the FDNPP into the environment. Nanofragments of an intrinsic U-phase were discovered to be closely associated with radioactive cesium-rich microparticles (CsMPs) in paddy soils collected ∼4 km from the FDNPP. The nanoscale fuel fragments were either encapsulated by or attached to CsMPs and occurred in two different forms: (i) UO 2+X nanocrystals of ∼70 nm size, which are embedded into magnetite associated with Tc and Mo on the surface and (ii) Isometric (U,Zr)O 2+X nanocrystals of ∼200 nm size, with the U/(U+Zr) molar ratio ranging from 0.14 to 0.91, with intrinsic pores (∼6 nm), indicating the entrapment of vapors or fission-product gases during crystallization. These results document the heterogeneous physical and chemical properties of debris at the nanoscale, which is a mixture of melted fuel and reactor materials, reflecting the complex thermal processes within the FDNPP reactor during meltdown. Still CsMPs are an important medium for the transport of debris fragments into the environment in a respirable form.

  1. The nuclear Thomas-Fermi model

    International Nuclear Information System (INIS)

    Myers, W.D.; Swiatecki, W.J.

    1994-08-01

    The statistical Thomas-Fermi model is applied to a comprehensive survey of macroscopic nuclear properties. The model uses a Seyler-Blanchard effective nucleon-nucleon interaction, generalized by the addition of one momentum-dependent and one density-dependent term. The adjustable parameters of the interaction were fitted to shell-corrected masses of 1654 nuclei, to the diffuseness of the nuclear surface and to the measured depths of the optical model potential. With these parameters nuclear sizes are well reproduced, and only relatively minor deviations between measured and calculated fission barriers of 36 nuclei are found. The model determines the principal bulk and surface properties of nuclear matter and provides estimates for the more subtle, Droplet Model, properties. The predicted energy vs density relation for neutron matter is in striking correspondence with the 1981 theoretical estimate of Friedman and Pandharipande. Other extreme situations to which the model is applied are a study of Sn isotopes from 82 Sn to 170 Sn, and the rupture into a bubble configuration of a nucleus (constrained to spherical symmetry) which takes place when Z 2 /A exceeds about 100

  2. The Nuclear Thomas-Fermi Model

    Science.gov (United States)

    Myers, W. D.; Swiatecki, W. J.

    1994-08-01

    The statistical Thomas-Fermi model is applied to a comprehensive survey of macroscopic nuclear properties. The model uses a Seyler-Blanchard effective nucleon-nucleon interaction, generalized by the addition of one momentum-dependent and one density-dependent term. The adjustable parameters of the interaction were fitted to shell-corrected masses of 1654 nuclei, to the diffuseness of the nuclear surface and to the measured depths of the optical model potential. With these parameters nuclear sizes are well reproduced, and only relatively minor deviations between measured and calculated fission barriers of 36 nuclei are found. The model determines the principal bulk and surface properties of nuclear matter and provides estimates for the more subtle, Droplet Model, properties. The predicted energy vs density relation for neutron matter is in striking correspondence with the 1981 theoretical estimate of Friedman and Pandharipande. Other extreme situations to which the model is applied are a study of Sn isotopes from {sup 82}Sn to {sup 170}Sn, and the rupture into a bubble configuration of a nucleus (constrained to spherical symmetry) which takes place when Z{sup 2}/A exceeds about 100.

  3. New approach to the nuclear in beam γ spectroscopy of neutron rich nuclei at N=20 using projectile fragmentation

    International Nuclear Information System (INIS)

    Lopez-Jimenez, M.J.; Saint-Laurent, M.G.; Achouri, L.; Daugas, J.M.; Belleguic, M.; Azaiez, F.; Bourgeois, C.; Angelique, J.C.

    1999-01-01

    The structure of nuclei far from stability around 32 Mg have been recently investigated by means of a novel method. In-beam γ-decay spectroscopy of a large number of exotic neutron-rich nuclei produced by projectile fragmentation of a 36 S projectile has been performed, using coincidences between the recoil fragments collected at the focal plane of SPEG spectrometer and γ-rays emitted at the target location. Preliminary results on both the population mechanism and the decay of excited states in nuclei around 32 Mg are presented. (author)

  4. Nuclear power investment risk economic model

    International Nuclear Information System (INIS)

    Postula, F.D.; Houghton, W.J.

    1986-01-01

    This paper describes the economic model which was developed to evaluate the net costs incurred by an owner due to an accident induced outage at a nuclear power plant. During such an outage, the portion of the plant operating costs associated with power production are saved; however the owner faces a sizable expense as fossil fuels are burned as a substitute for power from the incapacitated nuclear plant. Additional expenses are incurred by the owner for plant repair and, if necessary, decontamination cost. The model makes provision for mitigating these costs by sales of power, property damage insurance payments, tax write-offs and increased rates

  5. A polymer, random walk model for the size-distribution of large DNA fragments after high linear energy transfer radiation

    Science.gov (United States)

    Ponomarev, A. L.; Brenner, D.; Hlatky, L. R.; Sachs, R. K.

    2000-01-01

    DNA double-strand breaks (DSBs) produced by densely ionizing radiation are not located randomly in the genome: recent data indicate DSB clustering along chromosomes. Stochastic DSB clustering at large scales, from > 100 Mbp down to simulations and analytic equations. A random-walk, coarse-grained polymer model for chromatin is combined with a simple track structure model in Monte Carlo software called DNAbreak and is applied to data on alpha-particle irradiation of V-79 cells. The chromatin model neglects molecular details but systematically incorporates an increase in average spatial separation between two DNA loci as the number of base-pairs between the loci increases. Fragment-size distributions obtained using DNAbreak match data on large fragments about as well as distributions previously obtained with a less mechanistic approach. Dose-response relations, linear at small doses of high linear energy transfer (LET) radiation, are obtained. They are found to be non-linear when the dose becomes so large that there is a significant probability of overlapping or close juxtaposition, along one chromosome, for different DSB clusters from different tracks. The non-linearity is more evident for large fragments than for small. The DNAbreak results furnish an example of the RLC (randomly located clusters) analytic formalism, which generalizes the broken-stick fragment-size distribution of the random-breakage model that is often applied to low-LET data.

  6. Flexible bent rod model with a saturating induced dipole moment to study the electric linear dichroism of DNA fragments

    Science.gov (United States)

    Bertolotto, Jorge A.; Umazano, Juan P.

    2016-06-01

    In the present work we make a theoretical study of the steady state electric linear dichroism of DNA fragments in aqueous solution. The here developed theoretical approach considers a flexible bent rod model with a saturating induced dipole moment. The electric polarizability tensor of bent DNA fragments is calculated considering a phenomenological model which theoretical and experimental backgroung is presented here. The model has into account the electric polarizability longitudinal and transversal to the macroion. Molecular flexibility is described using an elastic potential. We consider DNA fragments originally bent with bending fluctuations around an average bending angle. The induced dipole moment is supposed constant once the electric field strength grows up at critical value. To calculate the reduced electric linear dichroism we determine the optical factor considering the basis of the bent DNA perpendicular to the molecular axis. The orientational distribution function has into account the anisotropic electric properties and the molecule flexibility. We applied the present theoretical background to fit electric dichroism experimental data of DNA fragments reported in the bibliography in a wide range of molecular weight and electric field. From these fits, values of DNA physical properties are estimated. We compare and discuss the results here obtained with the theoretical and experimental data presented by other authors. The original contributions of this work are: the inclusion of the transversal electric polarizability saturating with the electric field, the description of the electric properties with an electric polarizability tensor dependant on the bending angle and the use of an arc model originally bent.

  7. Nuclear uptake of an amino-terminal fragment of apolipoprotein E4 promotes cell death and localizes within microglia of the Alzheimer's disease brain.

    Science.gov (United States)

    Love, Julia E; Day, Ryan J; Gause, Justin W; Brown, Raquel J; Pu, Xinzhu; Theis, Dustin I; Caraway, Chad A; Poon, Wayne W; Rahman, Abir A; Morrison, Brad E; Rohn, Troy T

    2017-01-01

    Although harboring the apolipoprotein E4 ( APOE4 ) allele is a well known risk factor in Alzheimer's disease (AD), the mechanism by which it contributes to disease risk remains elusive. To investigate the role of proteolysis of apoE4 as a potential mechanism, we designed and characterized a site-directed cleavage antibody directed at position D151 of the mature form of apoE4 and E3. Characterization of this antibody indicated a high specificity for detecting synthesized recombinant proteins corresponding to the amino acid sequences 1-151 of apoE3 and E4 that would generate the 17 kDa (p17) fragment. In addition, this antibody also detected a ~17 kDa amino-terminal fragment of apoE4 following incubation with collagenase and matrix metalloproteinase-9 (MMP-9), but did not react with full-length apoE4. Application of this amino-terminal apoE cleavage-fragment (nApoECFp17) antibody, revealed nuclear labeling within glial cells and labeling of a subset of neurofibrillary tangles in the human AD brain. A quantitative analysis indicated that roughly 80% of labeled nuclei were microglia. To confirm these findings, cultured BV2 microglia cells were incubated with the amino-terminal fragment of apoE4 corresponding to the cleavage site at D151. The results indicated efficient uptake of this fragment and trafficking to the nucleus that also resulted in significant cell death. In contrast, a similarly designed apoE3 fragment showed no toxicity and primarily localized within the cytoplasm. These data suggest a novel cleavage event by which apoE4 is cleaved by the extracellular proteases, collagenase and MMP-9, generating an amino-terminal fragment that is then taken up by microglia, traffics to the nucleus and promotes cell death. Collectively, these findings provide important mechanistic insights into the mechanism by which harboring the APOE4 allele may elevate dementia risk observed in AD.

  8. The Fragmentation of Heavy Nuclei by 13.8 GeV/c Protons as a Contribution to the Study of the Interaction Mechanism and Nuclear Structure

    International Nuclear Information System (INIS)

    Gil Perez, D.

    1967-01-01

    We present he re an global study of the interaction between high- energy particles and heavy nuclei, an interaction which holds obvious interest in relation to the problems of nuclear fragmentation and which, up lo now has only been studied piecemeal. We have used three stacks of photographic emulsions which were irradiated by 13.8 GeV/c protons, 17 GeV/c negative pions and 24 GeV/c protons. All three irradiations took place in a 180 K.G. magnetic field using CERN beams. (Author) 20 refs

  9. Model for fusion and cool compound nucleus formation based on the fragmentation theory

    International Nuclear Information System (INIS)

    Malhotra, N.; Aroumougame, R.; Saroha, D.R.; Gupta, R.K.

    1986-01-01

    Collective potential energy surfaces are calculated in both the adiabatic and sudden approximations by using the asymmetric two-center shell model in the Strutinsky method. It is shown that fusion of two colliding heavy ions occurs by their crossing over of the adiabatic interaction barrier. The adiabatic scattering potentials present two barriers, whereas no barrier is shown to occur in sudden scattering potentials. The first barrier is obtained just past the saddle shape but is too low, such that a deep inelastic process is expected. The other, inner, barrier is high enough to let the system fall into the fusion well, whose excitation energy then determines whether a cool compound nucleus is produced or the fusion-fission process occurs. For a given compound nucleus, the excitation energy is found to be small for only a few target-projectile combinations, which increase as their mass asymmetry increases. Such target-projectile combinations which refer to a cool compound nucleus can be identified by a simple calculation of the fragmentation potential based on the ground state binding energies with Coulomb and proximity effects calculated at a constant relative separation of the two nuclei. Our calculations are made for the composite systems with 102 < or =Z < or =114

  10. Model for fusion and cool compound nucleus formation based on the fragmentation theory

    International Nuclear Information System (INIS)

    Malhotra, N.; Aroumougame, R.; Saroha, D.R.; Gupta, R.K.

    1985-07-01

    The collective potential energy surfaces are calculated in both the adiabatic and sudden approximations by using the asymmetric two centre shell model in Strutinsky method. It is shown that fusion of two colliding heavy ions occur by their crossing over of the adiabatic interaction barrier. The adiabatic scattering potentials present two barriers whereas no barrier is shown to occur in sudden scattering potentials. The first barrier is obtained just past the saddle shape but is too low, such that a deep inelastic process is expected. The other, inner, barrier is high enough to let the system fall into the fusion well, whose excitation energy then determine whether a cool compound nucleus is produced or the fusion-fission process occurs. For a given compound nucleus, the excitation energy is found to be small for only a few target-projectile combinations, which increase as their mass asymmetry increases. Such target-projectile combinations which refer to a cool compound nucleus, can be identified by a simple calculation of the fragmentation potential based on the ground state binding energies with Couloumb and proximity effects calculated at a constant relative separation of the two nuclei. Our calculations are made for the composite systems with 102<=Z<=114. (author)

  11. Dihadron fragmentation functions in the quark-jet model: Transversely polarized quarks

    Science.gov (United States)

    Matevosyan, Hrayr H.; Kotzinian, Aram; Thomas, Anthony W.

    2018-01-01

    Within the most recent extension of the quark-jet hadronization framework, we explore the transverse-polarization-dependent dihadron fragmentation functions (DiFFs) H1∢ and H1⊥ of a quark into π+π- pairs. Monte Carlo (MC) simulations are employed to model polarized quark hadronization and calculate the corresponding number densities. These, in turn, are used to extract the Fourier cosine moments of the DiFFs H1∢ and H1⊥. A notable finding is that there are previously unnoticed apparent discrepancies between the definitions of the so-called interference DiFF (IFF) H1∢ , entering the cross sections for two-hadron semi-inclusive electroproduction, and those involved in the production of two pairs of hadrons from back-to-back jets in electron-positron annihilation. This manuscript completes the studies of all four leading-twist DiFFs for unpolarized hadron pairs within the quark-jet framework, following our previous work on the helicity-dependent DiFF G1⊥.

  12. Calculation models for a nuclear reactor

    International Nuclear Information System (INIS)

    Tashanii, Ahmed Ali

    2010-01-01

    Determination of different parameters of nuclear reactors requires neutron transport calculations. Due to complicity of geometry and material composition of the reactor core, neutron calculations were performed for simplified models of the real arrangement. In frame of the present work two models were used for calculations. First, an elementary cell model was used to prepare cross section data set for a homogenized-core reactor model. The homogenized-core reactor model was then used to perform neutron transport calculation. The nuclear reactor is a tank-shaped thermal reactor. The semi-cylindrical core arrangement consists of aluminum made fuel bundles immersed in water which acts as a moderator as well as a coolant. Each fuel bundle consists of aluminum cladded fuel rods arranged in square lattices. (author)

  13. Universality of fragment shapes.

    Science.gov (United States)

    Domokos, Gábor; Kun, Ferenc; Sipos, András Árpád; Szabó, Tímea

    2015-03-16

    The shape of fragments generated by the breakup of solids is central to a wide variety of problems ranging from the geomorphic evolution of boulders to the accumulation of space debris orbiting Earth. Although the statistics of the mass of fragments has been found to show a universal scaling behavior, the comprehensive characterization of fragment shapes still remained a fundamental challenge. We performed a thorough experimental study of the problem fragmenting various types of materials by slowly proceeding weathering and by rapid breakup due to explosion and hammering. We demonstrate that the shape of fragments obeys an astonishing universality having the same generic evolution with the fragment size irrespective of materials details and loading conditions. There exists a cutoff size below which fragments have an isotropic shape, however, as the size increases an exponential convergence is obtained to a unique elongated form. We show that a discrete stochastic model of fragmentation reproduces both the size and shape of fragments tuning only a single parameter which strengthens the general validity of the scaling laws. The dependence of the probability of the crack plan orientation on the linear extension of fragments proved to be essential for the shape selection mechanism.

  14. A new model for nuclear matter

    International Nuclear Information System (INIS)

    Skyrme, T.H.R.

    1994-01-01

    The different values obtained for nuclear radii from electromagnetic interactions as compared with specifically nuclear interactions suggested a model of nuclear matter in which the meson field is supposed to condense into an incompressible fluid and the nucleonic sources are confined to its interior by a strong interaction between the sources and the fluid as a whole. The sources are also coupled to spin and charge fluctuations in the fluid, whose exchange leads to further internucleonic forces. It is necessary to postulate that the fluid have a comparatively low density; as a result rotational levels of the fluid are high, leading to a small probability of exchange of angular momentum (and charge coupled to it) with the sources. The values of the anomalous electrical interactions of nucleons deduced are in rough agreement with the facts. The nuclear structure indicated is a shell model embedded in the mesic fluid whose oscillations, strongly coupled to the nucleons, give rise to the collective features of nuclear structure as in the theory of Bohr and Mottelson. It is suggested that this picture of the mesic field may indicate where to look for solutions of the meson field equations. (author). 9 refs

  15. Organizational model of the nuclear sector

    International Nuclear Information System (INIS)

    Metri, Paulo

    2015-01-01

    The Brazilian Constitution prohibits private investment in many activities of the Nuclear Industry. Right now, it is in progress a constitutional amendment that allows private companies to build and operate nuclear power plants of its own. This work rescues the historical reasons that led the Congress of 1988 to choose the State owned model for this sector. In addition, the arguments that are used to propose the present changes are repeated here. As indicated in INAC 2015 website, 'sustainable development is supported by three pillars: social, economic and environmental'. Thus, the organizational model to be adopted for the Nuclear Sector must meet these requirements. The official objectives of the energy sector, as set out in the law 9,478, are remembered. New objectives, better established, and also adapted to the electrical subsector, are shown. Besides the use of these objectives to choose the sources and related technologies for the electric generation, they also can be used as evaluation criteria to help in the decision process of the organizational model for the Nuclear Sector. Acting in this way, it is ensured that social, economic and environmental requirements are being attended. Finally, if the developed evaluation criteria are applied, the impacts of each organizational model can be analyzed and preliminary conclusion and recommendation can be made. (author)

  16. Transient analysis models for nuclear power plants

    International Nuclear Information System (INIS)

    Agapito, J.R.

    1981-01-01

    The modelling used for the simulation of the Angra-1 start-up reactor tests, using the RETRAN computer code is presented. Three tests are simulated: a)nuclear power plant trip from 100% of power; b)great power excursions tests and c)'load swing' tests.(E.G.) [pt

  17. Organizational model of the nuclear sector

    Energy Technology Data Exchange (ETDEWEB)

    Metri, Paulo, E-mail: pmetri@cnen.gov.br [Comissao Nacional de Energia Nuclear (CNEN/CGRC), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    The Brazilian Constitution prohibits private investment in many activities of the Nuclear Industry. Right now, it is in progress a constitutional amendment that allows private companies to build and operate nuclear power plants of its own. This work rescues the historical reasons that led the Congress of 1988 to choose the State owned model for this sector. In addition, the arguments that are used to propose the present changes are repeated here. As indicated in INAC 2015 website, 'sustainable development is supported by three pillars: social, economic and environmental'. Thus, the organizational model to be adopted for the Nuclear Sector must meet these requirements. The official objectives of the energy sector, as set out in the law 9,478, are remembered. New objectives, better established, and also adapted to the electrical subsector, are shown. Besides the use of these objectives to choose the sources and related technologies for the electric generation, they also can be used as evaluation criteria to help in the decision process of the organizational model for the Nuclear Sector. Acting in this way, it is ensured that social, economic and environmental requirements are being attended. Finally, if the developed evaluation criteria are applied, the impacts of each organizational model can be analyzed and preliminary conclusion and recommendation can be made. (author)

  18. Conservation laws and nuclear transport models

    International Nuclear Information System (INIS)

    Gale, C.; Das Gupta, S.

    1990-01-01

    We discuss the consequences of energy and angular momentum conservation for nucleon-nucleon scattering in a nuclear environment during high-energy heavy-ion collisions. We describe algorithms that ensure stricter enforcement of such conservation laws within popular microscopic models of intermediate-energy heavy-ion collisions. We find that the net effects on global observables are small

  19. Sleep fragmentation exacerbates mechanical hypersensitivity and alters subsequent sleep-wake behavior in a mouse model of musculoskeletal sensitization.

    Science.gov (United States)

    Sutton, Blair C; Opp, Mark R

    2014-03-01

    Sleep deprivation, or sleep disruption, enhances pain in human subjects. Chronic musculoskeletal pain is prevalent in our society, and constitutes a tremendous public health burden. Although preclinical models of neuropathic and inflammatory pain demonstrate effects on sleep, few studies focus on musculoskeletal pain. We reported elsewhere in this issue of SLEEP that musculoskeletal sensitization alters sleep of mice. In this study we hypothesize that sleep fragmentation during the development of musculoskeletal sensitization will exacerbate subsequent pain responses and alter sleep-wake behavior of mice. This is a preclinical study using C57BL/6J mice to determine the effect on behavioral outcomes of sleep fragmentation combined with musculoskeletal sensitization. Musculoskeletal sensitization, a model of chronic muscle pain, was induced using two unilateral injections of acidified saline (pH 4.0) into the gastrocnemius muscle, spaced 5 days apart. Musculoskeletal sensitization manifests as mechanical hypersensitivity determined by von Frey filament testing at the hindpaws. Sleep fragmentation took place during the consecutive 12-h light periods of the 5 days between intramuscular injections. Electroencephalogram (EEG) and body temperature were recorded from some mice at baseline and for 3 weeks after musculoskeletal sensitization. Mechanical hypersensitivity was determined at preinjection baseline and on days 1, 3, 7, 14, and 21 after sensitization. Two additional experiments were conducted to determine the independent effects of sleep fragmentation or musculoskeletal sensitization on mechanical hypersensitivity. Five days of sleep fragmentation alone did not induce mechanical hypersensitivity, whereas sleep fragmentation combined with musculoskeletal sensitization resulted in prolonged and exacerbated mechanical hypersensitivity. Sleep fragmentation combined with musculoskeletal sensitization had an effect on subsequent sleep of mice as demonstrated by increased

  20. Dynamic fragmentation of laser shock-melted tin: experiment and modelling

    Energy Technology Data Exchange (ETDEWEB)

    De Resseguier, T. [CNRS ENSMA, Lab Combust and Deton, F-86961 Futuroscope (France); Signor, L.; Dragon, A. [CNRS ENSMA, Mecan and Phys Mat Lab, F-86961 Futuroscope (France); Signor, L.; Roy, G. [CEA Valduc, 21 - Is-sur-Tille (France)

    2010-07-01

    Dynamic fragmentation of shock-loaded metals is an issue of considerable importance for both basic science and a variety of technological applications, such as pyrotechnics or inertial confinement fusion, the latter involving high energy laser irradiation of thin metallic shells. Whereas spall fracture in solid materials has been extensively studied for many years, little data can be found yet about the evolution of this phenomenon after partial or full melting on compression or on release. Here, we present an investigation of dynamic fragmentation in laser shock-melted tin, from the 'micro-spall' process (ejection of a cloud of fine droplets) occurring upon reflection of the compressive pulse from the target free surface, to the late rupture observed in the un-spalled melted layer (leading to the formation of larger spherical fragments). Experimental results consist of time-resolved velocity measurements and post-shock observations of recovered targets and fragments. They provide original information regarding the loss of tensile strength associated with melting, the cavitation mechanism likely to occur in the melted metal, the sizes of the subsequent fragments and their ejection velocities. A theoretical description based on an energetic approach adapted to the case of a liquid metal is implemented as a failure criterion in a one-dimensional hydro-code including a multi-phase equation of state for tin. The resulting predictions of the micro-spall process are compared with experimental data. In particular, the use of a new experimental technique to quantify the fragment size distributions leads to a much better agreement with theory than previously reported. Finally, a complementary approach focused on cavitation is proposed to evaluate the role of this phenomenon in the fragmentation of the melted metal. (authors)

  1. Partial Gene Cloning and Enzyme Structure Modeling of Exolevanase Fragment from Bacillus subtilis

    Science.gov (United States)

    Azhar, M.; Natalia, D.; Syukur, S.; Andriani, N.; Jamsari, J.

    2018-04-01

    Inulin hydrolysis thermophilic and thermotolerant bacteria are potential sources of inulin hydrolysis enzymes. Partial gene that encodes inulin hydrolysis enzymes had been isolated from Bacillus subtilis using polymerase chain reaction (PCR) method with the DPE.slFandDPE.eR degenerative primers. The partial gene was cloned into pGEM-T Easy vector with E. coli as host cells and analyzed using BLASTx, CrustalW2, and Phyre2 programs. Size of thepartial gene had been found539 bp that encoded 179aminoacid residues of protein fragment. The sequences of protein fragment was more similar to exolevanase than exoinulinase. The protein fragment had conserved motif FSGS, and specific hits GH32 β-fructosidase. It had three residues of active site and five residues of substrate binding. The active site on the protein fragment were D (1-WLNDP-5), D (125-FRDPK-129) and E (177-WEC-179). Substrate binding on the protein fragment were ND (1-WLNDP-5), Q (18-FYQY-21), FS (60-FSGS-63) RD (125-FRDPK-129) and E (177-WEC-179).

  2. Scaling laws for modeling nuclear reactor systems

    International Nuclear Information System (INIS)

    Nahavandi, A.N.; Castellana, F.S.; Moradkhanian, E.N.

    1979-01-01

    Scale models are used to predict the behavior of nuclear reactor systems during normal and abnormal operation as well as under accident conditions. Three types of scaling procedures are considered: time-reducing, time-preserving volumetric, and time-preserving idealized model/prototype. The necessary relations between the model and the full-scale unit are developed for each scaling type. Based on these relationships, it is shown that scaling procedures can lead to distortion in certain areas that are discussed. It is advised that, depending on the specific unit to be scaled, a suitable procedure be chosen to minimize model-prototype distortion

  3. Study on frugmentation of one-quasiparticle and one-phonon states in the quasiparticle-phonon nuclear model

    International Nuclear Information System (INIS)

    Solov'ev, V.G.

    1980-01-01

    The general assumptions of the quasiparticle-phonon nuclear model are given. This model describes the few-quasiparticle components of the wave functions at low, intermediate and high excitation energies. The method of strength functions which plays a key role in describing complex nuclei is also presented. A further development of the quasiparticle-phonon nuclear model is outlined. The fragmentation of one-quasiparticle and one-phonon states over nuclear levels is studied. The results on the fragmentation of deep hole states in spherical nuclei are presented, which describe well the experimental data. The neutron strength functions and their spin dependence are calculated. A good agreement with experiment is obtained. The energies and widths of the giant resonances are calculated in spherical and deformed nuclei. The information on the many-quasiparticle components of excited state wave functions is shown to be very scarce. The necessity of studying the few-quasiparticle configurations is pointed out

  4. Experimental test of nuclear magnetization distribution and nuclear structure models

    International Nuclear Information System (INIS)

    Beirsdorfer, P; Crespo-Lopez-Urrutia, J R; Utter, S B.

    1999-01-01

    Models exist that ascribe the nuclear magnetic fields to the presence of a single nucleon whose spin is not neutralized by pairing it up with that of another nucleon; other models assume that the generation of the magnetic field is shared among some or all nucleons throughout the nucleus. All models predict the same magnetic field external to the nucleus since this is an anchor provided by experiments. The models differ, however, in their predictions of the magnetic field arrangement within the nucleus for which no data exist. The only way to distinguish which model gives the correct description of the nucleus would be to use a probe inserted into the nucleus. The goal of our project was to develop exactly such a probe and to use it to measure fundamental nuclear quantities that have eluded experimental scrutiny. The need for accurately knowing such quantities extends far beyond nuclear physics and has ramifications in parity violation experiments on atomic traps and the testing of the standard model in elementary particle physics. Unlike scattering experiments that employ streams of free particles, our technique to probe the internal magnetic field distribution of the nucleus rests on using a single bound electron. Quantum mechanics shows that an electron in the innermost orbital surrounding the nucleus constantly dives into the nucleus and thus samples the fields that exist inside. This sampling of the nucleus usually results in only minute shifts in the electron s average orbital, which would be difficult to detect. By studying two particular energy states of the electron, we can, however, dramatically enhance the effects of the distribution of the magnetic fields in the nucleus. In fact about 2% of the energy difference between the two states, dubbed the hyperfine splitting, is determined by the effects related to the distribution of magnetic fields in the nucleus, A precise measurement of this energy difference (better than 0.01%) would then allow us to place

  5. A semi-empirical formula on the pre-neutron-emission fragment mass distribution in nuclear fission

    International Nuclear Information System (INIS)

    Wang Fucheng; Hu Jimin

    1988-03-01

    A 5-Gauss semi-empirical formula on the pre-neutron-emission fragment mass distribution is given. The absolute standard deviation and maximum departure between calculated values and experimental data for (n,f) and (n,n'f) fission reactions from 232 Th to 245 Cm are approximately 0.4% and 0.8%, respectively. The error will get bigger if the formula is used at higher excitation energies

  6. QUEIMAP: a computer routine for punctual analysis of a nuclear fuel depletion with accumulation of fission fragments

    International Nuclear Information System (INIS)

    Couto, R.T.

    1990-01-01

    QUEIMAP is a computer routine for burnup calculation, composed of five FORTRAN-77 subroutines. Its objective is to solve depletion equation of four radionuclides conversion chain, U238, U235, Th232, as well as fission fragments equations. In this paper the burnup is considered punctual and evolutioned under cross section. It presents the solution algorithms employed by QUEIMAP, the validation of its results and the way of use it. (M.I.)

  7. Thermochemical modeling of nuclear waste glass

    International Nuclear Information System (INIS)

    Spear, K.E.; Besmann, T.M.; Beahm, E.C.

    1998-06-01

    The development of assessed and consistent phase equilibria and thermodynamic data for major glass constituents used to incorporate high-level nuclear waste is discussed in this paper. The initial research has included the binary Na 2 O-SiO 2 , Na 2 O-Al 2 O 3 , and SiO 2 -Al 2 O 3 systems. The nuclear waste glass is assumed to be a supercooled liquid containing the constituents in the glass at temperatures of interest for nuclear waste storage. Thermodynamic data for the liquid solutions were derived from mathematical comparisons of phase diagram information and the thermodynamic data available for crystalline solid phases. An associate model is used to describe the liquid solution phases. Utilizing phase diagram information provides very stringent limits on the relative thermodynamic stabilities of all phases which exist in a given system

  8. Apoptotic DNA Degradation into Oligonucleosomal Fragments, but Not Apoptotic Nuclear Morphology, Relies on a Cytosolic Pool of DFF40/CAD Endonuclease*

    Science.gov (United States)

    Iglesias-Guimarais, Victoria; Gil-Guiñon, Estel; Gabernet, Gisela; García-Belinchón, Mercè; Sánchez-Osuna, María; Casanelles, Elisenda; Comella, Joan X.; Yuste, Victor J.

    2012-01-01

    Apoptotic cell death is characterized by nuclear fragmentation and oligonucleosomal DNA degradation, mediated by the caspase-dependent specific activation of DFF40/CAD endonuclease. Here, we describe how, upon apoptotic stimuli, SK-N-AS human neuroblastoma-derived cells show apoptotic nuclear morphology without displaying concomitant internucleosomal DNA fragmentation. Cytotoxicity afforded after staurosporine treatment is comparable with that obtained in SH-SY5Y cells, which exhibit a complete apoptotic phenotype. SK-N-AS cell death is a caspase-dependent process that can be impaired by the pan-caspase inhibitor q-VD-OPh. The endogenous inhibitor of DFF40/CAD, ICAD, is correctly processed, and dff40/cad cDNA sequence does not reveal mutations altering its amino acid composition. Biochemical approaches show that both SH-SY5Y and SK-N-AS resting cells express comparable levels of DFF40/CAD. However, the endonuclease is poorly expressed in the cytosolic fraction of healthy SK-N-AS cells. Despite this differential subcellular distribution of DFF40/CAD, we find no differences in the subcellular localization of both pro-caspase-3 and ICAD between the analyzed cell lines. After staurosporine treatment, the preferential processing of ICAD in the cytosolic fraction allows the translocation of DFF40/CAD from this fraction to a chromatin-enriched one. Therefore, the low levels of cytosolic DFF40/CAD detected in SK-N-AS cells determine the absence of DNA laddering after staurosporine treatment. In these cells DFF40/CAD cytosolic levels can be restored by the overexpression of their own endonuclease, which is sufficient to make them proficient at degrading their chromatin into oligonucleosome-size fragments after staurosporine treatment. Altogether, the cytosolic levels of DFF40/CAD are determinants in achieving a complete apoptotic phenotype, including oligonucleosomal DNA degradation. PMID:22253444

  9. Feasibility Study for the Measurement of Nuclear Fragmentation Cross Sections with NA61/SHINE at the CERN SPS

    CERN Document Server

    Aduszkiewicz, A

    2017-01-01

    A detailed knowledge of the fragmentation cross sections of intermediate mass nuclei is of paramount importance to understand the propagation of cosmic rays in our Galaxy and to evaluate the background for dark matter searches with space-based cosmic-ray experiments such as AMS. Therefore, we suggest a one-week test run in 2018 with secondary ions to establish the capabilities of NA61/SHINE to measure fragmentation cross sections at isotope level. No major modifications to the experimental setup of NA61/SHINE are needed to perform this feasibility study. The experience gained during the test run will be used to formulate a comprehensive measurement campaign for cosmic-ray related fragmentation cross sections for the possible extension of the NA61/SHINE physics program beyond 2020. The test data on carbon-proton and oxygen-proton interactions at 13A GeV/c that we intend to collect during the proposed test run have already the potential to reduce the current cross section uncertainties.

  10. Angular distributions of evaporated particles, fission and intermediate-mass fragments: on the search for consistent models

    International Nuclear Information System (INIS)

    Alexander, J.M.

    1987-01-01

    During the last two years there has been a true cacophony concerning the meaning of experimental angular distributions for fission and fission-like fragments. The heavily used, saddle-point, transition-state model has been shown to be of limited value for high-spin systems, and a wide variety of proposals has appeared often with mutual inconsistencies and conflicting views. Even though equilibrium statistical models for fragment emission and particle evaporation must have a very close kinship, this relationship, often left as murky, has now come onto center stage for understanding reactions at ≥ 100 MeV. Basic questions concern the nature of the decision-point configurations, their degrees of freedom, the role of deformation and the relevant moments of inertia. This paper points out serious inconsistencies in several recent scission-point models and discusses conditions for applicability of saddle-point and scission-point approaches

  11. Percolation-fission model study of the fragment mass distribution for the 1 GeV proton induced reaction

    International Nuclear Information System (INIS)

    Katsuma, Masahiko; Kobayashi, Hiroshi; Sawada, Tetsuo; Sasa, Toshinobu

    2005-01-01

    The 1 GeV proton induced reaction on 208 Pb targets is analyzed by using the percolation model combined with the Atchison fission model. The fragment mass distribution and the isotopic production cross sections obtained from our model are compared with the experimental data. The trends of the fragment mass distribution for the 1 GeV proton induced reaction can be reproduced by our calculation in some degree. The order of magnitude for the calculated isotopic production cross sections at the calculated peak positions is similar to that of the experimental peak values. The calculated peak positions of the isotopic production cross sections are shifted to the heavier region than those of the experimental data. (author)

  12. Model Action Plan for Nuclear Forensics and Nuclear Attribution

    International Nuclear Information System (INIS)

    Dudder, G B; Niemeyer, S; Smith, D K; Kristo, M J

    2004-01-01

    Nuclear forensics and nuclear attribution have become increasingly important tools in the fight against illegal trafficking in nuclear and radiological materials. This technical report documents the field of nuclear forensics and nuclear attribution in a comprehensive manner, summarizing tools and procedures that have heretofore been described independently in the scientific literature. This report also provides national policy-makers, decision-makers, and technical managers with guidance for responding to incidents involving the interdiction of nuclear and radiological materials. However, due to the significant capital costs of the equipment and the specialized expertise of the personnel, work in the field of nuclear forensics has been restricted so far to a handful of national and international laboratories. In fact, there are a limited number of specialists who have experience working with interdicted nuclear materials and affiliated evidence. Most of the laboratories that have the requisite equipment, personnel, and experience to perform nuclear forensic analysis are participants in the Nuclear Smuggling International Technical Working Group or ITWG (see Section 1.8). Consequently, there is a need to disseminate information on an appropriate response to incidents of nuclear smuggling, including a comprehensive approach to gathering evidence that meets appropriate legal standards and to developing insights into the source and routes of nuclear and radiological contraband. Appendix A presents a ''Menu of Options'' for other Member States to request assistance from the ITWG Nuclear Forensics Laboratories (INFL) on nuclear forensic cases

  13. Nuclear fragmentation for Xe+Au and Xe+Ag systems at an energy of 44 A.MeV, formation and decay of hot nuclei; Etude de la fragmentation nucleaire pour les systemes XE+AU et XE+AG a 44 A.MeV, production et decroissance de noyaux chauds

    Energy Technology Data Exchange (ETDEWEB)

    Meslin, C.

    1995-01-01

    A study of the formation and the decay of hot nuclear fragments produced in the reactions Xe+Au and Xe+Ag at an energy of 44 A.MeV is presented in this thesis. The 4{pi} experimental setup consisted of four multidetectors -two for the detection of the fragments (Z>7; DELF and XYZT) and two for the detection of the charged particles (Z<6; MUR and TONNEAU) and allowed an analysis using ``complete events`` (80 % of the total charge and the total parallel linear momentum of the entrance channel) to be carried out. The reaction mechanism is binary with as observed at low energy an almost complete relaxation of the incident energy. The collision results in two hot fragments at the beginning of the exit channel which decay by evaporation and/or fragmentation. In addition of these two body events, we have identified a new dynamic mechanism where we detect a small fragment, called the neck, coming form the overlap of the nuclei during the interaction, in coincidence with a projectile-like fragment and a target-like fragment. For the most dissipative collisions, the deep inelastic collision have allowed an estimation of the lifetime of the hot nuclear fragments to be made. This is possible using proximity effects and fragment-fragment space-time correlations of the decay of one or two primary partners from the deep inelastic collisions. This method is seen to reach its limits in the case of the reactions studied here. (authors). 61 refs.

  14. A simple model for the quark fragmentation functions seen in deep inelastic processes

    International Nuclear Information System (INIS)

    Seiden, A.

    1977-01-01

    Using some simple assumptions, a calculation is presented of the quark fragmentation functions seen in deep inelastic processes. The results provide evidence for the conjecture that both jets seen in high p(perpendicular) reactions at the ISR stem from similar parents. The calculated functions are in excellent agreement with the inclusive distributions seen in γp and anti γp scattering, and in particular explain the puzzling presence of leading π - 's from the fragmentation of a leading up quark. The results are also in agreement with the charge ratios extracted from deep inelastic electron scattering. (Auth.)

  15. Rotating bubble and toroidal nuclei and fragmentation

    International Nuclear Information System (INIS)

    Royer, G.; Haddad, F.; Jouault, B.

    1995-01-01

    The energy of rotating bubble and toroidal nuclei predicted to be formed in central heavy-ion collisions at intermediate energies is calculated within the generalized rotating liquid drop model. The potential barriers standing in these exotic deformation paths are compared with the three dimensional and plane fragmentation barriers. In the toroidal deformation path of the heaviest systems exists a large potential pocket localised below the plane fragmentation barriers. This might allow the temporary survival of heavy nuclear toroids before the final clusterization induced by the surface and proximity tension. (author)

  16. Percolation versus microcanonical fragmentation - comparison of fragment size distribution: Where is the liquid-gas transition in nuclei?

    International Nuclear Information System (INIS)

    Jaqaman, H.R.; Birzeit Univ.; Papp, G.; Eoetvoes Lorand Tudomanyegyetem, Budapest; Gross, D.H.E.; Freie Univ. Berlin

    1990-01-01

    The distributions of fragments produced by microcanonical multifragmentation of hot nuclei are compared with the cluster distributions predicted by a bond percolation model on a finite lattice. The conditional moments of these distributions are used together with the correlations between the largest three fragments in each event. Whereas percolation and statistical nuclear fragmentation agree in many details as in the usual plots of the averaged moments of the fragment distributions which yield the critical exponents, they turn out to be essentially different when less averaged quantities or correlations are considered. The differences between the predictions of the two models are mainly due to the particularities of the nuclear problem, especially the effect of the long-range Coulomb force which favours the break-up of the highly excited nucleus into two large fragments (pseudo-fission) and, to a somewhat lesser extent, enhances the possibility for the cracking of the nucleus into more than two large fragments. The fission events are, however, clearly separated from a second branch of critical correlations which shows up clearly in both nuclear fragmentation and percolation. We think that this critical correlation branch is due to the liquid-gas phase transition in finite nuclei. (orig.)

  17. Dynamics of fragments and associated phenomena in heavy-ion collisions using a modified secondary algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Rohit [Department of Physics, Panjab University, Chandigarh-160014 (India)

    2016-05-06

    We discuss the stability of fragments identified by secondary algorithms used to construct fragments within quantum molecular dynamics model. For this purpose we employ three different algorithms for fragment identification. 1) The conventional minimum spanning tree (MST) method based on the spatial correlations, 2) an improved version of MST with additional binding energy constraints of cold nuclear matter, 3) and that of hot matter. We find significant role of thermal binding energies over cold matter binding energies. Significant role is observed for fragment multiplicities and stopping of fragments. Whereas insignificant effect is observed on fragment’s flow.

  18. Pressurizer model for Embalse nuclear power plant

    International Nuclear Information System (INIS)

    Parkansky, D.G.; Bedrossian, G.C.

    1993-01-01

    Since the models normally used for he simulation of eventual accidents at the Embalse nuclear power plant with the FIREBIRD III code did not work satisfactorily when the pressurizer becomes empty of liquid, a new model was developed. This report presents the governing equations as well as the calculation technique, for which a computer program was made. An example of application is also presented. The results show that this new model can easily solve the problem of lack of liquid in the pressurizer, as it lets the fluid enter and exit freely, according to the pressure transient at the reactor outlet headers. (author)

  19. Analysis of proton-induced fragment production cross sections by the Quantum Molecular Dynamics plus Statistical Decay Model

    Energy Technology Data Exchange (ETDEWEB)

    Chiba, Satoshi; Iwamoto, Osamu; Fukahori, Tokio; Niita, Koji; Maruyama, Toshiki; Maruyama, Tomoyuki; Iwamoto, Akira [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    The production cross sections of various fragments from proton-induced reactions on {sup 56}Fe and {sup 27}Al have been analyzed by the Quantum Molecular Dynamics (QMD) plus Statistical Decay Model (SDM). It was found that the mass and charge distributions calculated with and without the statistical decay have very different shapes. These results also depend strongly on the impact parameter, showing an importance of the dynamical treatment as realized by the QMD approach. The calculated results were compared with experimental data in the energy region from 50 MeV to 5 GeV. The QMD+SDM calculation could reproduce the production cross sections of the light clusters and intermediate-mass to heavy fragments in a good accuracy. The production cross section of {sup 7}Be was, however, underpredicted by approximately 2 orders of magnitude, showing the necessity of another reaction mechanism not taken into account in the present model. (author)

  20. [Studies of target fragmentation in intermediate energy, relativistic and ultra-relativistic nuclear collisions]. Nuclear chemistry progress report, August 1, 1990--August 1, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Loveland, W.D.

    1991-08-01

    The work described herein is part of a project involving the study of low energy (< 10 MeV/A), intermediate energy (10--100 MeV/A) and relativistic (> 250 MeV/A) heavy ion reactions. In the low energy regime, we published a monograph on the properties of the heaviest elements and used that publication as a basis for making a set of ``best`` semi-empirical predictions of heavy element decay properties. The intermediate energy research effort focussed upon the completion of studies already begun and the initiation of a number of new experiments. In our study of a interaction of 21 MeV/nucleon {sup 129}Xe with {sup 197}Au, we compared the characteristics of the observed deep inelastic phenomena with various models of dissipative reactions and found significant discrepancies between observations and predictions. These discrepancies seemed to be caused by an improper treatment of pre-equilibrium in the early stages of the collision. In our study of the relativistic interaction of 400 MeV/nucleon {sup 12}C with {sup 197}Au, we reported the first direct physical measurement of the properties of the spallation residues from a nucleus-nucleus collision. We found the residue energies to be much lower than those predicted by the intranuclear cascade model, indicating some substantial modifications of that model are needed. But, we also found, indications of significant, non-zero values of the residue transverse momentum, a finding that calls into question the interpretation of a number of radiochemical recoil studies of the kinematics of high energy reactions. A program of performing numerical simulations of intermediate and high energy nuclear collisions using the QMD model was initiated.

  1. Relativistic nuclear physics with the spectator model

    International Nuclear Information System (INIS)

    Gross, F.

    1988-01-01

    The spectator model, a general approach to the relativistic treatment of nuclear physics problems in which spectators to nuclear interactions are put on their mass-shell, will be defined nd described. The approach grows out of the relativistic treatment of two and three body systems in which one particle is off-shell, and recent numerical results for the NN interaction will be presented. Two meson-exchange models, one with only 4 mesons (π, σ, /rho/, ω) but with a 25% admixture of γ 5 coupling for the pion, and a second with 6 mesons (π, σ, /rho/, ω, δ, and /eta/) but a pure γ 5 γ/sup mu/ pion coupling, are shown to give very good quantitative fits to NN scattering phase shifts below 400 MeV, and also a good description of the /rho/ 40 Cα elastic scattering observables. 19 refs., 6 figs., 1 tab

  2. Nuclear security assessment with Markov model approach

    International Nuclear Information System (INIS)

    Suzuki, Mitsutoshi; Terao, Norichika

    2013-01-01

    Nuclear security risk assessment with the Markov model based on random event is performed to explore evaluation methodology for physical protection in nuclear facilities. Because the security incidences are initiated by malicious and intentional acts, expert judgment and Bayes updating are used to estimate scenario and initiation likelihood, and it is assumed that the Markov model derived from stochastic process can be applied to incidence sequence. Both an unauthorized intrusion as Design Based Threat (DBT) and a stand-off attack as beyond-DBT are assumed to hypothetical facilities, and performance of physical protection and mitigation and minimization of consequence are investigated to develop the assessment methodology in a semi-quantitative manner. It is shown that cooperation between facility operator and security authority is important to respond to the beyond-DBT incidence. (author)

  3. Model wells for nuclear well logging

    International Nuclear Information System (INIS)

    Tittle, C.W.

    1989-01-01

    Considerations needed in the design and construction of model wells for nuclear log calibration are covered, with special attention to neutron porosity logging and total γ-ray logging. Pulsed neutron decay-time and spectral γ-ray logging are discussed briefly. The American Petroleum Institute calibration facility for nuclear logs is a good starting point for similar or expanded facilities. A few of its shortcomings are mentioned; they are minor. The problem of fluid saturation is emphasized. Attention is given to models made of consolidated rock and those containing unconsolidated material such as Ottawa sand. Needed precautions are listed. A similarity method is presented for estimating the porosity index of formations that are not fully saturated. (author)

  4. Flexible bent rod model with a saturating induced dipole moment to study the electric linear dichroism of DNA fragments

    Directory of Open Access Journals (Sweden)

    Jorge A. Bertolotto

    2016-06-01

    Full Text Available In the present work we make a theoretical study of the steady state electric linear dichroism of DNA fragments in aqueous solution. The here developed theoretical approach considers a flexible bent rod model with a saturating induced dipole moment. The electric polarizability tensor of bent DNA fragments is calculated considering a phenomenological model which theoretical and experimental backgroung is presented here. The model has into account the electric polarizability longitudinal and transversal to the macroion. Molecular flexibility is described using an elastic potential. We consider DNA fragments originally bent with bending fluctuations around an average bending angle. The induced dipole moment is supposed constant once the electric field strength grows up at critical value. To calculate the reduced electric linear dichroism we determine the optical factor considering the basis of the bent DNA perpendicular to the molecular axis. The orientational distribution function has into account the anisotropic electric properties and the molecule flexibility. We applied the present theoretical background to fit electric dichroism experimental data of DNA fragments reported in the bibliography in a wide range of molecular weight and electric field. From these fits, values of DNA physical properties are estimated. We compare and discuss the results here obtained with the theoretical and experimental data presented by other authors. The original contributions of this work are: the inclusion of the transversal electric polarizability saturating with the electric field, the description of the electric properties with an electric polarizability tensor dependant on the bending angle and the use of an arc model originally bent.

  5. Evaluation of two endometriosis models by transplantation of human endometrial tissue fragments and human endometrial mesenchymal cells

    Directory of Open Access Journals (Sweden)

    Mina Jafarabadi

    2017-08-01

    Full Text Available Background: The animal models of endometriosis could be a valuable alternative tool for clarifying the etiology of endometriosis. Objective: In this study two endometriosis models at the morphological and molecular levels was evaluated and compared. Materials and Methods: The human endometrial tissues were cut into small fragments then they were randomly considered for transplantation into γ irradiated mice as model A; or they were isolated and cultured up to fourth passages. 2×106 cultured stromal cells were transplanted into γ irradiated mice subcutaneously as model B. twenty days later the ectopic tissues in both models were studied morphologically by Periodic acid-Schiff and hematoxylin and eosin staining. The expression of osteopontin (OPN and matrix metalloproteinase 2 (MMP2 genes were also assessed using real time RT-PCR. 17-β estradiol levels of mice sera were compared before and after transplantation. Results: The endometrial like glands and stromal cells were formed in the implanted subcutaneous tissue of both endometriosis models. The gland sections per cubic millimeter, the expression of OPN and MMP2 genes and the level of 17-β estradiol were higher in model B than model A (p=0.03. Conclusion: Our observation demonstrated that endometrial mesenchymal stromal cells showed more efficiency to establish endometriosis model than human endometrial tissue fragments.

  6. Non-functional plastid ndh gene fragments are present in the nuclear genome of Norway spruce (Picea abies L. Karsch): insights from in silico analysis of nuclear and organellar genomes.

    Science.gov (United States)

    Ranade, Sonali Sachin; García-Gil, María Rosario; Rosselló, Josep A

    2016-04-01

    Many genes have been lost from the prokaryote plastidial genome during the early events of endosymbiosis in eukaryotes. Some of them were definitively lost, but others were relocated and functionally integrated to the host nuclear genomes through serial events of gene transfer during plant evolution. In gymnosperms, plastid genome sequencing has revealed the loss of ndh genes from several species of Gnetales and Pinaceae, including Norway spruce (Picea abies). This study aims to trace the ndh genes in the nuclear and organellar Norway spruce genomes. The plastid genomes of higher plants contain 11 ndh genes which are homologues of mitochondrial genes encoding subunits of the proton-pumping NADH-dehydrogenase (nicotinamide adenine dinucleotide dehydrogenase) or complex I (electron transport chain). Ndh genes encode 11 NDH polypeptides forming the Ndh complex (analogous to complex I) which seems to be primarily involved in chloro-respiration processes. We considered ndh genes from the plastidial genome of four gymnosperms (Cryptomeria japonica, Cycas revoluta, Ginkgo biloba, Podocarpus totara) and a single angiosperm species (Arabidopsis thaliana) to trace putative homologs in the nuclear and organellar Norway spruce genomes using tBLASTn to assess the evolutionary fate of ndh genes in Norway spruce and to address their genomic location(s), structure, integrity and functionality. The results obtained from tBLASTn were subsequently analyzed by performing homology search for finding ndh specific conserved domains using conserved domain search. We report the presence of non-functional plastid ndh gene fragments, excepting ndhE and ndhG genes, in the nuclear genome of Norway spruce. Regulatory transcriptional elements like promoters, TATA boxes and enhancers were detected in the upstream regions of some ndh fragments. We also found transposable elements in the flanking regions of few ndh fragments suggesting nuclear rearrangements in those regions. These evidences

  7. Fission and fragmentation of silver and bromine nuclei by 1-6 GeV energy photons

    International Nuclear Information System (INIS)

    Pinheiro Filho, J. de D.

    1983-01-01

    Fission and fragmentation of silver and bromine nuclei induced by bremsstrahlung photons in the maximum energy range of 1-6 GeV are studied. A special technique of nuclear emulsion for the highly ionizing nuclear fragment detection is used in the discrimination between nuclear fission and fragmentation events. Films of Ilford-KO nuclear emulsion (approximatelly 10 20 atoms/cm 2 of Ag, Br) which had been exposed to bremsstrahlung beams in 'Deutsches Elektronen Synchrotron' (DESY, Hamburg) with total doses of approximatelly 10 11 equivalent photons are used. Through a detailed analysis of range, angular and angle between fragment distributions, and empirical relations which permit to estimate nuclear fragment energy, range and velocity, the discrimination between fission and fragmentation events is made. Results related to fragment range distribution, angular distribution, distribution of angle between fragments, distribution of ratio between ranges, velocity distributions, forward/backward ratio, fission and fragmentation cross sections, nuclear fissionability and ternary fission frequency are presented and discussed. The results show that the mean photofragmentation cross section in the internal 1-6 GeV (0,09+-0,02mb) is significant when compared to the photofission (0,29+-0,05mb). It is also shown that the mean photofission cross section between 1 and 6 GeV is great by a factor of approximatelly 10 when compared to the foreseen by the cascade-evaporation nuclear model for monoenergetic photons of 0,6 GeV. (L.C.) [pt

  8. Energy production using fission fragment rockets

    International Nuclear Information System (INIS)

    Chapline, G.; Matsuda, Y.

    1991-08-01

    Fission fragment rockets are nuclear reactors with a core consisting of thin fibers in a vacuum, and which use magnetic fields to extract the fission fragments from the reactor core. As an alternative to ordinary nuclear reactors, fission fragment rockets would have the following advantages: Approximately twice as efficient if one can directly convert the fission fragment energy into electricity; by reducing the buildup of a fission fragment inventory in the reactor one could avoid a Chernobyl type disaster; and collecting the fission fragments outside the reactor could simplify the waste disposal problem. 6 refs., 4 figs., 2 tabs

  9. The influence of fragmentation models on the determination of the strong coupling constant in e+e- annihilation into hadrons

    International Nuclear Information System (INIS)

    Behrend, H.J.; Chen, C.; Fenner, H.; Schachter, M.J.; Schroeder, V.; Sindt, H.; D'Agostini, G.; Apel, W.D.; Banerjee, S.; Bodenkamp, J.; Chrobaczek, D.; Engler, J.; Fluegge, G.; Fries, D.C.; Fues, W.; Gamerdinger, K.; Hopp, G.; Kuester, H.; Mueller, H.; Randoll, H.; Schmidt, G.; Schneider, H.; Boer, W. de; Buschhorn, G.; Grindhammer, G.; Grosse-Wiesmann, P.; Gunderson, B.; Kiesling, C.; Kotthaus, R.; Kruse, U.; Lierl, H.; Lueers, D.; Oberlack, H.; Schacht, P.; Colas, P.; Cordier, A.; Davier, M.; Fournier, D.; Grivaz, J.F.; Haissinski, J.; Journe, V.; Klarsfeld, A.; Laplanche, F.; Le Diberder, F.; Mallik, U.; Veillet, J.J.; Field, J.H.; George, R.; Goldberg, M.; Grossetete, B.; Hamon, O.; Kapusta, F.; Kovacs, F.; London, G.; Poggioli, L.; Rivoal, M.; Aleksan, R.; Bouchez, J.; Carnesecchi, G.; Cozzika, G.; Ducros, Y.; Gaidot, A.; Jadach, S.; Lavagne, Y.; Pamela, J.; Pansart, J.P.; Pierre, F.

    1983-01-01

    Hadronic events obtained with the CELLO detector at PETRA were compared with first-order QCD predictions using two different models for the fragmentation of quarks and gluons, the Hoyer model and the Lund model. Both models are in reasonable agreement with the data, although they do not completely reproduce the details of many distributions. Several methods have been applied to determine the strong coupling constant αsub(s). Although within one model the value of αsub(s) varies by 20% among the different methods, the values determined using the Lund model are 30% or more larger (depending on the method used) than the values determined with the Hoyer model. Our results using the Hoyer model are in agreement with previous results based on this approach. (orig.)

  10. Stochastic model of energetic nuclear reactor

    International Nuclear Information System (INIS)

    Bojko, R.V.; Ryazanov, V.V.

    2002-01-01

    Behaviour of nuclear reactor was treated using the theory of branching processes. As mathematical model descriptive the neutron number in time the Markov occasional process is proposed. Application of branching occasional processes with variable regime to the description of neutron behaviour in the reactor makes possible conducting strong description of critical operation regime and demonstrates the severity of the process. Three regimes of the critical behaviour depending on the sign of manipulated variables and feedbacks were discovered. Probability regularities peculiar to the behaviour of the reactor are embodied to the suggested stochastic model [ru

  11. A phenomenological model for nuclear multifragmentation

    International Nuclear Information System (INIS)

    Souza, S.R.; Leray, S.; Paula, L. de; Nemeth, J.; Ngo, C.; CEA Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette; Ngo, H.

    1992-01-01

    A phenomenological model for nuclear multifragmentation is presented. It is made up of two complementary parts: molecular dynamics and restructured aggregation. It is applied to study the multifragmentation of 16 O+ 80 Br system at several bombarding energies. The results turn out to be in good agreement with available emulsion data. The production of charged particles and IMF as a function of the bombarding energy is also studied. The results seem to agree quite well with experimental observations and with previous results of other model calculations. (author) 19 refs.; 5 figs.; 1 tab

  12. Effects of introduction of new resources and fragmentation of existing resources on limiting wealth distribution in asset exchange models

    Science.gov (United States)

    Ali Saif, M.; Gade, Prashant M.

    2009-03-01

    Pareto law, which states that wealth distribution in societies has a power-law tail, has been the subject of intensive investigations in the statistical physics community. Several models have been employed to explain this behavior. However, most of the agent based models assume the conservation of number of agents and wealth. Both these assumptions are unrealistic. In this paper, we study the limiting wealth distribution when one or both of these assumptions are not valid. Given the universality of the law, we have tried to study the wealth distribution from the asset exchange models point of view. We consider models in which (a) new agents enter the market at a constant rate (b) richer agents fragment with higher probability introducing newer agents in the system (c) both fragmentation and entry of new agents is taking place. While models (a) and (c) do not conserve total wealth or number of agents, model (b) conserves total wealth. All these models lead to a power-law tail in the wealth distribution pointing to the possibility that more generalized asset exchange models could help us to explain the emergence of a power-law tail in wealth distribution.

  13. A hidden Markov model to assess drug-induced sleep fragmentation in the telemetered rat

    OpenAIRE

    Diack, C.; Ackaert, O.; Ploeger, B. A.; van der Graaf, P. H.; Gurrell, R.; Ivarsson, M.; Fairman, D.

    2011-01-01

    Drug-induced sleep fragmentation can cause sleep disturbances either via their intended pharmacological action or as a side effect. Examples of disturbances include excessive daytime sleepiness, insomnia and nightmares. Developing drugs without these side effects requires insight into the mechanisms leading to sleep disturbance. The characterization of the circadian sleep pattern by EEG following drug exposure has improved our understanding of these mechanisms and their translatability across...

  14. Few-body models for nuclear astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Descouvemont, P., E-mail: pdesc@ulb.ac.be [Physique Nucléaire Théorique et Physique Mathématique, C.P. 229, Université Libre de Bruxelles (ULB), B 1050 Brussels (Belgium); Baye, D., E-mail: dbaye@ulb.ac.be [Physique Nucléaire Théorique et Physique Mathématique, C.P. 229, Université Libre de Bruxelles (ULB), B 1050 Brussels (Belgium); Physique Quantique, C.P. 165/82, Université Libre de Bruxelles (ULB), B 1050 Brussels (Belgium); Suzuki, Y., E-mail: suzuki@nt.sc.niigata-u.ac.jp [Department of Physics, Niigata University, Niigata 950-2181 (Japan); RIKEN Nishina Center, Wako 351-0198 (Japan); Aoyama, S., E-mail: aoyama@cc.niigata-u.ac.jp [Center for Academic Information Service, Niigata University, Niigata 950-2181 (Japan); Arai, K., E-mail: arai@nagaoka-ct.ac.jp [Division of General Education, Nagaoka National College of Technology, 888 Nishikatakai, Nagaoka, Niigata 940-8532 (Japan)

    2014-04-15

    We present applications of microscopic models to nuclear reactions of astrophysical interest, and we essentially focus on few-body systems. The calculation of radiative-capture and transfer cross sections is outlined, and we discuss the corresponding reaction rates. Microscopic theories are briefly presented, and we emphasize on the matrix elements of four-body systems. The microscopic extension of the R-matrix theory to nuclear reactions is described. Applications to the {sup 2}H(d, γ){sup 4}He, {sup 2}H(d, p){sup 3}H and {sup 2}H(d, n){sup 3}He reactions are presented. We show the importance of the tensor force to reproduce the low-energy behaviour of the cross sections.

  15. Analysis of U2 small nuclear RNA fragments in the bile differentiates cholangiocarcinoma from primary sclerosing cholangitis and other benign biliary disorders.

    Science.gov (United States)

    Baraniskin, Alexander; Nöpel-Dünnebacke, Stefanie; Schumacher, Brigitte; Gerges, Christian; Bracht, Thilo; Sitek, Barbara; Meyer, Helmut E; Gerken, Guido; Dechene, Alexander; Schlaak, Jörg F; Schroers, Roland; Pox, Christian; Schmiegel, Wolff; Hahn, Stephan A

    2014-07-01

    Up to now the diagnosis of early stage cholangiocarcinoma (CC) has remained difficult, with low sensitivities reported for current diagnostic methods. Based on recent promising findings about circulating U2 small nuclear RNA fragments (RNU2-1f) as novel blood-based biomarkers for pancreatic and colorectal adenocarcinoma, we studied the utility of RNU2-1f as a diagnostic marker of CC in bile fluid. Bile fluid was collected from patients with CC (n = 12), controls (patients with choledocholithiasis) (n = 11) and with primary sclerosing cholangitis (PSC; n = 11). RNU2-1f levels were measured by real-time polymerase chain reaction normalized to cel-54. Measurement of RNU2-1f levels in bile fluids enabled the differentiation of patients with CC from controls in all cases. Furthermore, RNU2-1f levels in bile fluids of patients with CC were significantly higher than in patients with PSC, resulting in a receiver-operating characteristic curve area of 0.856, with sensitivity of 67 % and specificity of 91 %. Our data suggest that the measurement of RNU2-1 fragments detected in the bile fluid can be used as a diagnostic marker for CC and should be included in future prospective diagnostic studies for this disease entity.

  16. Combinatorial nuclear level-density model

    International Nuclear Information System (INIS)

    Uhrenholt, H.; Åberg, S.; Dobrowolski, A.; Døssing, Th.; Ichikawa, T.; Möller, P.

    2013-01-01

    A microscopic nuclear level-density model is presented. The model is a completely combinatorial (micro-canonical) model based on the folded-Yukawa single-particle potential and includes explicit treatment of pairing, rotational and vibrational states. The microscopic character of all states enables extraction of level-distribution functions with respect to pairing gaps, parity and angular momentum. The results of the model are compared to available experimental data: level spacings at neutron separation energy, data on total level-density functions from the Oslo method, cumulative level densities from low-lying discrete states, and data on parity ratios. Spherical and deformed nuclei follow basically different coupling schemes, and we focus on deformed nuclei

  17. Heavy fragment radioactivity

    International Nuclear Information System (INIS)

    Silisteanu, I.

    1991-06-01

    The effect of collective mode excitation in heavy fragment radioactivity (HFR) is explored and discussed in the light of current experimental data. It is found that the coupling and resonance effects in fragment interaction and also the proper angular momentum effects may lead to an important enhancing of the emission process. New useful procedures are proposed for the study of nuclear decay properties. The relations between different decay processes are investigated in detail. We are also trying to understand and explain in a unified way the reaction mechanisms in decay phenomena. (author). 17 refs, 4 figs, 3 tabs

  18. International Nuclear Model personal computer (PCINM): Model documentation

    International Nuclear Information System (INIS)

    1992-08-01

    The International Nuclear Model (INM) was developed to assist the Energy Information Administration (EIA), U.S. Department of Energy (DOE) in producing worldwide projections of electricity generation, fuel cycle requirements, capacities, and spent fuel discharges from commercial nuclear reactors. The original INM was developed, maintained, and operated on a mainframe computer system. In spring 1992, a streamlined version of INM was created for use on a microcomputer utilizing CLIPPER and PCSAS software. This new version is known as PCINM. This documentation is based on the new PCINM version. This document is designed to satisfy the requirements of several categories of users of the PCINM system including technical analysts, theoretical modelers, and industry observers. This document assumes the reader is familiar with the nuclear fuel cycle and each of its components. This model documentation contains four chapters and seven appendices. Chapter Two presents the model overview containing the PCINM structure and process flow, the areas for which projections are made, and input data and output reports. Chapter Three presents the model technical specifications showing all model equations, algorithms, and units of measure. Chapter Four presents an overview of all parameters, variables, and assumptions used in PCINM. The appendices present the following detailed information: variable and parameter listings, variable and equation cross reference tables, source code listings, file layouts, sample report outputs, and model run procedures. 2 figs

  19. Biological effectiveness of high-energy protons - Target fragmentation

    International Nuclear Information System (INIS)

    Cucinotta, F.A.; Katz, R.; Wilson, J.W.; Townsend, L.W.; Shinn, J.; Hajnal, F.

    1991-01-01

    High-energy protons traversing tissue produce local sources of high-linear-energy-transfer ions through nuclear fragmentation. The contribution of these target fragments to the biological effectiveness of high-energy protons using the cellular track model is examined. The effects of secondary ions are treated in terms of the production collision density using energy-dependent parameters from a high-energy fragmentation model. Calculations for mammalian cell cultures show that at high dose, at which intertrack effects become important, protons deliver damage similar to that produced by gamma rays, and with fragmentation the relative biological effectiveness (RBE) of protons increases moderately from unity. At low dose, where sublethal damage is unimportant, the contribution from target fragments dominates, causing the proton effectiveness to be very different from that of gamma rays with a strongly fluence-dependent RBE. At high energies, the nuclear fragmentation cross sections become independent of energy. This leads to a plateau in the proton single-particle-action cross section, below 1 keV/micron, since the target fragments dominate. 29 refs

  20. Fragmentation in central collisions of heavy systems

    International Nuclear Information System (INIS)

    Claesson, G.; Doss, K.G.R.; Ferguson, R.

    1987-01-01

    One of the goals of heavy ion reaction studies is to understand the fragmentation of hot nuclei. The LBL/GSI Plastic Ball detector system has been used to achieve a very high solid angle for detection of light and medium-heavy fragments emitted in 200 Mev/A Au + Au and Au + Fe reactions. The simultaneous measurement of almost all of the nucleons and nuclei resulting from each collision allows an estimation of the total charged particle multiplicity and hence the impact parameter. By choosing subsets of the data corresponding to a peripheral or central collision, the assumptions inherent in various models of nuclear fragmentation can be tested. 3 refs., 3 figs

  1. Urban meteorological modelling for nuclear emergency preparedness

    International Nuclear Information System (INIS)

    Baklanov, Alexander; Sorensen, Jens Havskov; Hoe, Steen Cordt; Amstrup, Bjarne

    2006-01-01

    The main objectives of the current EU project 'Integrated Systems for Forecasting Urban Meteorology, Air Pollution and Population Exposure' (FUMAPEX) are the improvement of meteorological forecasts for urban areas, the connection of numerical weather prediction (NWP) models to urban air pollution and population dose models, the building of improved urban air quality information and forecasting systems, and their application in cities in various European climates. In addition to the forecast of the worst air-pollution episodes in large cities, the potential use of improved weather forecasts for nuclear emergency management in urban areas, in case of hazardous releases from nuclear accidents or terror acts, is considered. Such use of NWP data is tested for the Copenhagen metropolitan area and the Oresund region. The Danish Meteorological Institute (DMI) is running an experimental version of the HIRLAM NWP model over Zealand including the Copenhagen metropolitan area with a horizontal resolution of 1.4 km, thus approaching the city-scale. This involves 1-km resolution physiographic data with implications for the urban surface parameters, e.g. surface fluxes, roughness length and albedo. For the city of Copenhagen, the enhanced high-resolution NWP forecasting will be provided to demonstrate the improved dispersion forecasting capabilities of the Danish nuclear emergency preparedness decision-support system, the Accident Reporting and Guidance Operational System (ARGOS), used by the Danish Emergency Management Agency (DEMA). Recently, ARGOS has been extended with a capability of real-time calculation of regional-scale atmospheric dispersion of radioactive material from accidental releases. This is effectuated through on-line interfacing with the Danish Emergency Response Model of the Atmosphere (DERMA), which is run at DMI. For local-scale modelling of atmospheric dispersion, ARGOS utilises the Local-Scale Model Chain (LSMC), which makes use of high-resolution DMI

  2. Evaluating realized seed dispersal across fragmented tropical landscapes: a two-fold approach using parentage analysis and the neighbourhood model.

    Science.gov (United States)

    Ismail, Sascha A; Ghazoul, Jaboury; Ravikanth, Gudasalamani; Kushalappa, Cheppudira G; Uma Shaanker, Ramanan; Kettle, Chris J

    2017-05-01

    Despite the importance of seed dispersal for survival of plant species in fragmented landscapes, data on seed dispersal at landscape scales remain sparse. Effective seed dispersal among fragments determines recolonization and plant species persistence in such landscapes. We present the first large-scale (216-km 2 ) direct estimates of realized seed dispersal of a high-value timber tree (Dysoxylum malabaricum) across an agro-forest landscape in the Western Ghats, India. Based upon an exhaustive inventory of adult trees and a sample of 488 seedlings all genotyped at 10 microsatellite loci, we estimated realized seed dispersal using parentage analysis and the neighbourhood model. Our estimates found that most realized seed dispersal was within 200 m, which is insufficient to effectively bridge the distances between forest patches. We conclude that using mobility of putative animal dispersers can be misleading when estimating tropical tree species vulnerability to habitat fragmentation. This raises serious concerns about the potential of many tropical trees to recolonize isolated forest patches where high-value tree species have already been removed. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  3. Controlled fragmentation

    International Nuclear Information System (INIS)

    Arnold, Werner

    2002-01-01

    Contrary to natural fragmentation, controlled fragmentation offers the possibility to adapt fragment parameters like size and mass to the performance requirements in a very flexible way. Known mechanisms like grooves inside the casing, weaken the structure. This is, however, excluded for applications with high accelerations during launch or piercing requirements for example on a semi armor piercing penetrator. Another method to achieve controlled fragmentation with an additional grid layer is presented with which the required grooves are produced 'just in time' inside the casing during detonation of the high explosive. The process of generating the grooves aided by the grid layer was studied using the hydrocode HULL with respect to varying grid designs and material combinations. Subsequent to this, a large range of these theoretically investigated combinations was contemplated in substantial experimental tests. With an optimised grid design and a suitable material selection, the controlled fragment admits a very flexible adaptation to the set requirements. Additional advantages like the increase of perforation performance or incendiary amplification can be realized with the grid layer

  4. Radioimmunolocalization and selective delivery of radiation in a rat model system: comparison of intact and fragmented antibody

    International Nuclear Information System (INIS)

    Walker, K.Z.; Seymour-Munn, K.; Axiak, S.M.; Raison, R.L.; Basten, A.; Towson, J.E.; Bautovitch, G.J.; Morris, J.

    1988-01-01

    Monoclonal antibody (MoAb) fragments are known to have advantages over intact immunoglobulins for radioimmunoscintigraphy. It is less clear whether they are as effective in the delivery of radioimmunotherapy. The imaging and dosimetric properties of an intact MoAb, K-1-21, reactive against human kappa light chains (LC) were compared with that of its F(ab') 2 and Fab fragments using a normal rat model system. Two days after injection of 131 I-K-1-21 into rats bearing antigen-sepharose implants, gamma camera images showed specific localization of the MoAb to the target (kappa LC) but not to the control (lambda LC) implant. Better images were obtained with K-1-21 F(ab') 2 than with Fab or intact antibody. Mean kappa implant: blood ratios were 8.6 ± 3.9 for Fab, 7.9 ± 1.8 for F(ab') 2 and 2.0 ± 0.3 for intact K-1-21. The improvement associated with the use of 131 I-K-1-21 fragments was, however, achieved at the expense of lower absolute values of activity at the target site. Thus the absorbed dose delivered to the implant by the intact K-1-21 was double that delivered with F(ab') 2 and six times that delivered with Fab. As intact K-1-21 also delivered a greater radiation dose to normal tissues, F(ab') 2 fragments may have the greatest overall advantages for therapy with radionuclide MoAb conjugates. (author)

  5. Modeling closed nuclear fuel cycles processes

    Energy Technology Data Exchange (ETDEWEB)

    Shmidt, O.V. [A.A. Bochvar All-Russian Scientific Research Institute for Inorganic Materials, Rogova, 5a street, Moscow, 123098 (Russian Federation); Makeeva, I.R. [Zababakhin All-Russian Scientific Research Institute of Technical Physics, Vasiliev street 13, Snezhinsk, Chelyabinsk region, 456770 (Russian Federation); Liventsov, S.N. [Tomsk Polytechnic University, Tomsk, Lenin Avenue, 30, 634050 (Russian Federation)

    2016-07-01

    Computer models of processes are necessary for determination of optimal operating conditions for closed nuclear fuel cycle (NFC) processes. Computer models can be quickly changed in accordance with new and fresh data from experimental research. 3 kinds of process simulation are necessary. First, the VIZART software package is a balance model development used for calculating the material flow in technological processes. VIZART involves taking into account of equipment capacity, transport lines and storage volumes. Secondly, it is necessary to simulate the physico-chemical processes that are involved in the closure of NFC. The third kind of simulation is the development of software that allows the optimization, diagnostics and control of the processes which implies real-time simulation of product flows on the whole plant or on separate lines of the plant. (A.C.)

  6. System model development for nuclear thermal propulsion

    International Nuclear Information System (INIS)

    Walton, J.T.; Perkins, K.R.; Buksa, J.J.; Worley, B.A.; Dobranich, D.

    1992-01-01

    A critical enabling technology in the evolutionary development of nuclear thermal propulsion (NTP) is the ability to predict the system performance under a variety of operating conditions. Since October 1991, US (DOE), (DOD) and NASA have initiated critical technology development efforts for NTP systems to be used on Space Exploration Initiative (SEI) missions to the Moon and Mars. This paper presents the strategy and progress of an interagency NASA/DOE/DOD team for NTP system modeling. It is the intent of the interagency team to develop several levels of computer programs to simulate various NTP systems. An interagency team was formed for this task to use the best capabilities available and to assure appropriate peer review. The vision and strategy of the interagency team for developing NTP system models will be discussed in this paper. A review of the progress on the Level 1 interagency model is also presented

  7. Nuclear physics for applications. A model approach

    International Nuclear Information System (INIS)

    Prussin, S.G.

    2007-01-01

    Written by a researcher and teacher with experience at top institutes in the US and Europe, this textbook provides advanced undergraduates minoring in physics with working knowledge of the principles of nuclear physics. Simplifying models and approaches reveal the essence of the principles involved, with the mathematical and quantum mechanical background integrated in the text where it is needed and not relegated to the appendices. The practicality of the book is enhanced by numerous end-of-chapter problems and solutions available on the Wiley homepage. (orig.)

  8. Fluctuations in the fragmentation process

    International Nuclear Information System (INIS)

    Botet, R.; Ploszajczak, M.

    1993-01-01

    Some general framework of sequential fragmentation is presented, as provided by the newly proposed Fragmentation - Inactivation - Binary model, and to study briefly its basic and universal features. This model includes as particular cases most of the previous kinetic fragmentation models. In particular it is discussed how one arrives in this framework to the critical behaviour, called the shattering transition. This model is then compared to recent data on gold multifragmentation at 600 MeV/nucl. (authors) 20 refs., 5 figs

  9. Nuclear reactor core modelling in multifunctional simulators

    International Nuclear Information System (INIS)

    Puska, E.K.

    1999-01-01

    The thesis concentrates on the development of nuclear reactor core models for the APROS multifunctional simulation environment and the use of the core models in various kinds of applications. The work was started in 1986 as a part of the development of the entire APROS simulation system. The aim was to create core models that would serve in a reliable manner in an interactive, modular and multifunctional simulator/plant analyser environment. One-dimensional and three-dimensional core neutronics models have been developed. Both models have two energy groups and six delayed neutron groups. The three-dimensional finite difference type core model is able to describe both BWR- and PWR-type cores with quadratic fuel assemblies and VVER-type cores with hexagonal fuel assemblies. The one- and three-dimensional core neutronics models can be connected with the homogeneous, the five-equation or the six-equation thermal hydraulic models of APROS. The key feature of APROS is that the same physical models can be used in various applications. The nuclear reactor core models of APROS have been built in such a manner that the same models can be used in simulator and plant analyser applications, as well as in safety analysis. In the APROS environment the user can select the number of flow channels in the three-dimensional reactor core and either the homogeneous, the five- or the six-equation thermal hydraulic model for these channels. The thermal hydraulic model and the number of flow channels have a decisive effect on the calculation time of the three-dimensional core model and thus, at present, these particular selections make the major difference between a safety analysis core model and a training simulator core model. The emphasis on this thesis is on the three-dimensional core model and its capability to analyse symmetric and asymmetric events in the core. The factors affecting the calculation times of various three-dimensional BWR, PWR and WWER-type APROS core models have been

  10. Nuclear reactor core modelling in multifunctional simulators

    Energy Technology Data Exchange (ETDEWEB)

    Puska, E.K. [VTT Energy, Nuclear Energy, Espoo (Finland)

    1999-06-01

    The thesis concentrates on the development of nuclear reactor core models for the APROS multifunctional simulation environment and the use of the core models in various kinds of applications. The work was started in 1986 as a part of the development of the entire APROS simulation system. The aim was to create core models that would serve in a reliable manner in an interactive, modular and multifunctional simulator/plant analyser environment. One-dimensional and three-dimensional core neutronics models have been developed. Both models have two energy groups and six delayed neutron groups. The three-dimensional finite difference type core model is able to describe both BWR- and PWR-type cores with quadratic fuel assemblies and VVER-type cores with hexagonal fuel assemblies. The one- and three-dimensional core neutronics models can be connected with the homogeneous, the five-equation or the six-equation thermal hydraulic models of APROS. The key feature of APROS is that the same physical models can be used in various applications. The nuclear reactor core models of APROS have been built in such a manner that the same models can be used in simulator and plant analyser applications, as well as in safety analysis. In the APROS environment the user can select the number of flow channels in the three-dimensional reactor core and either the homogeneous, the five- or the six-equation thermal hydraulic model for these channels. The thermal hydraulic model and the number of flow channels have a decisive effect on the calculation time of the three-dimensional core model and thus, at present, these particular selections make the major difference between a safety analysis core model and a training simulator core model. The emphasis on this thesis is on the three-dimensional core model and its capability to analyse symmetric and asymmetric events in the core. The factors affecting the calculation times of various three-dimensional BWR, PWR and WWER-type APROS core models have been

  11. Circulating U2 small nuclear RNA fragments as a novel diagnostic biomarker for pancreatic and colorectal adenocarcinoma

    DEFF Research Database (Denmark)

    Baraniskin, Alexander; Nöpel-Dünnebacke, Stefanie; Ahrens, Maike

    2013-01-01

    Improved non-invasive strategies for early cancer detection are urgently needed to reduce morbidity and mortality. Non-coding RNAs, such as microRNAs and small nucleolar RNAs, have been proposed as biomarkers for non-invasive cancer diagnosis. Analyzing serum derived from nude mice implanted...... with primary human pancreatic ductal adenocarcinoma (PDAC), we identified 15 diagnostic microRNA candidates. Of those miR-1246 was selected based on its high abundance in serum of tumor carrying mice. Subsequently, we noted a cross reactivity of the established miR-1246 assays with RNA fragments derived from U...... that hsa-miR-1246 is likely a pseudo microRNA. In a next step, RNU2-1f was measured by qRT-PCR and normalized to cel-54 in 191 serum/plasma samples from PDAC and colorectal carcinoma (CRC) patients. In comparison to 129 controls, we were able to classify samples as cancerous with a sensitivity...

  12. Chameleon fragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Brax, Philippe [Institut de Physique Théorique, CEA, IPhT, CNRS, URA 2306, F-91191Gif/Yvette Cedex (France); Upadhye, Amol, E-mail: philippe.brax@cea.fr, E-mail: aupadhye@anl.gov [Institute for the Early Universe, Ewha University, International Education, Building #601, 11-1, Daehyun-Dong Seodaemun-Gu, Seoul 120-750 (Korea, Republic of)

    2014-02-01

    A scalar field dark energy candidate could couple to ordinary matter and photons, enabling its detection in laboratory experiments. Here we study the quantum properties of the chameleon field, one such dark energy candidate, in an ''afterglow'' experiment designed to produce, trap, and detect chameleon particles. In particular, we investigate the possible fragmentation of a beam of chameleon particles into multiple particle states due to the highly non-linear interaction terms in the chameleon Lagrangian. Fragmentation could weaken the constraints of an afterglow experiment by reducing the energy of the regenerated photons, but this energy reduction also provides a unique signature which could be detected by a properly-designed experiment. We show that constraints from the CHASE experiment are essentially unaffected by fragmentation for φ{sup 4} and 1/φ potentials, but are weakened for steeper potentials, and we discuss possible future afterglow experiments.

  13. Chameleon fragmentation

    International Nuclear Information System (INIS)

    Brax, Philippe; Upadhye, Amol

    2014-01-01

    A scalar field dark energy candidate could couple to ordinary matter and photons, enabling its detection in laboratory experiments. Here we study the quantum properties of the chameleon field, one such dark energy candidate, in an ''afterglow'' experiment designed to produce, trap, and detect chameleon particles. In particular, we investigate the possible fragmentation of a beam of chameleon particles into multiple particle states due to the highly non-linear interaction terms in the chameleon Lagrangian. Fragmentation could weaken the constraints of an afterglow experiment by reducing the energy of the regenerated photons, but this energy reduction also provides a unique signature which could be detected by a properly-designed experiment. We show that constraints from the CHASE experiment are essentially unaffected by fragmentation for φ 4 and 1/φ potentials, but are weakened for steeper potentials, and we discuss possible future afterglow experiments

  14. Densities and temperatures at fragment formation in heavy-ion collision

    Energy Technology Data Exchange (ETDEWEB)

    Ohnishi, Akira [Hokkaido Univ., Sapporo (Japan)

    1998-07-01

    In order to clarify whether the liquid-gas phase transition is relevant to the multi-fragment formation found in intermediate energy heavy-ion collisions, we estimate the densities and temperatures at fragment formation in Au+Au collisions at incident energies of 150 MeV/A and 400 MeV/A within the Quantum Molecular Dynamics (QMD) model with and without quantum fluctuations implemented according to the Quantal Langevin (QL) model. The calculated results show that the IMFs are mainly produced inside the unstable region of nuclear matter, which supports the idea of the fragment formation from supercooled nuclear matter. (author)

  15. Nuclear power investment risk economic model

    International Nuclear Information System (INIS)

    Houghton, W.J.; Postula, F.D.

    1985-12-01

    This paper describes an economic model which was developed to evaluate the net costs incurred by a utility due to an accident induced outage at a nuclear power plant. During such an outage the portion of the plant operating costs associated with power production are saved; however, the owning utility faces a sizable expense as fossil fuels are burned as a substitute for the incapacitated nuclear power. Additional expenses are incurred by the utility for plant repair and if necessary, decontamination costs. The model makes provision for mitigating these costs by sales of power, property damage insurance payments, tax write-offs and increased rates. Over 60 economic variables contribute to the net cost uncertainty. The values of these variables are treated as uncertainty distributions and are used in a Monte carlo computer program to evaluate the cost uncertainty (investment risk) associated with damage which could occur from various categories of initiating accidents. As an example, results of computations for various levels of damage associated with a loss of coolant accident are shown as a range of consequential plant downtime and unrecovered cost. A typical investment risk profile is shown for these types of accidents. Cost/revenue values for each economic factor are presented for a Three Mile Island - II type accident, e.g., uncontrolled core heatup. 4 refs., 6 figs., 3 tabs

  16. The imagine of establishing China nuclear insurance model

    International Nuclear Information System (INIS)

    Wu Yimin

    2010-01-01

    Nuclear power Insurance is one important technique for risk managements of Nuclear power Enterprises. At present, nuclear risk of Nuclear power plants in China has been mainly supported by China Nuclear Insurance pool (hereinafter called CNP) to get coverage from International Nuclear Insurance pool (hereinafter called NIP). CNIP has several advantages to confirm low-cost. Operation, such as large underwriting capacity, international approval and cession, direct writing without agents. However, there are both deficiencies, first, can not get rid of dependence on International markets ; second, in the absence of competition in Self- insurance organizations , tough and opaque premium offer greatly restricted the enthusiasm for Nuclear power plants insuring .But the next ten year is a golden decade for China Nuclear industry development; Nuclear power market is demonstrating tremendous growth potential. With new units put into operation, all kinds of nuclear insurance demand will release when subject-matter insured substantially increase. So, breaking the current bottleneck of China Nuclear Insurance and establishing China Nuclear Insurance (hereinafter called: Nuclear insurance) model adapting to China national conditions will play an important role in Nuclear power development. I made the advice that both domestic nuclear enterprises and general insurance companies initiate a 'Nuclear insurance company'. (authors)

  17. Scission configurations and their implication in fission-fragment angular momenta

    International Nuclear Information System (INIS)

    Bonneau, L.; Quentin, P.; Mikhailov, I. N.

    2007-01-01

    The generation of sizable angular momenta in fragments formed in low-energy nuclear fission is described microscopically within the general quantum-mechanical framework of orientation pumping due to the Heisenberg uncertainty principle. Within this framework, we make use of the results of Skyrme-Hartree-Fock plus BCS-pairing calculations of fragment deformabilities to deduce a distribution of fission-fragment spins as a function of the fragment total excitation energy. We consider a fragmentation corresponding to a pair of deformed fragments and for which fission data are available. The properties of the scission configurations determine to a large extent the fission-fragment spins. This is why we pay particular attention to quantitatively defining the scission configurations and to studying the various implications of such a specific choice. A fair qualitative agreement with data is demonstrated and discussed within the limits of the simple scission-configuration model used here

  18. Bespoke Fragments

    DEFF Research Database (Denmark)

    Kruse Aagaard, Anders

    2017-01-01

    The PhD project Bespoke Fragments is investigating the space emerging in the exploration of the relationship between digital drawing and fabrication, and the field of materials and their properties and capacities. Through a series of different experiments, the project situates itself in a shuttli...

  19. Rock fragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Brown, W.S.; Green, S.J.; Hakala, W.W.; Hustrulid, W.A.; Maurer, W.C. (eds.)

    1976-01-01

    Experts in rock mechanics, mining, excavation, drilling, tunneling and use of underground space met to discuss the relative merits of a wide variety of rock fragmentation schemes. Information is presented on novel rock fracturing techniques; tunneling using electron beams, thermocorer, electric spark drills, water jets, and diamond drills; and rock fracturing research needs for mining and underground construction. (LCL)

  20. Recent progress on perturbative QCD fragmentation functions

    International Nuclear Information System (INIS)

    Cheung, K.

    1995-05-01

    The recent development of perturbative QCD (PQCD) fragmentation functions has strong impact on quarkonium production. I shall summarize B c meson production based on these PQCD fragmentation functions, as well as, the highlights of some recent activities on applying these PQCD fragmentation functions to explain anomalous J/ψ and ψ' production at the Tevatron. Finally, I discuss a fragmentation model based on the PQCD fragmentation functions for heavy quarks fragmenting into heavy-light mesons

  1. A simple dynamic rising nuclear cloud based model of ground radioactive fallout for atmospheric nuclear explosion

    International Nuclear Information System (INIS)

    Zheng Yi

    2008-01-01

    A simple dynamic rising nuclear cloud based model for atmospheric nuclear explosion radioactive prediction was presented. The deposition of particles and initial cloud radius changing with time before the cloud stabilization was considered. Large-scale relative diffusion theory was used after cloud stabilization. The model was considered reasonable and dependable in comparison with four U.S. nuclear test cases and DELFIC model results. (authors)

  2. Modelling fragmentations of amino-acids after resonant electron attachment: quantum evidence of possible direct -OH detachment

    Energy Technology Data Exchange (ETDEWEB)

    Panosetti, C.; Sebastianelli, F.; Gianturco, F.A. [Department of Chemistry and CNISM, University of Rome -La Sapienza-, Roma (Italy); Baccarelli, I. [CASPUR, Supercomputing Consortium for University and Research, Roma (Italy)

    2010-10-15

    We investigate some aspects of the radiation damage mechanisms in biomolecules, focusing on the modelling of resonant fragmentation caused by the attachment of low-energy electrons (LEEs) initially ejected by biological tissues when exposed to ionizing radiation. Scattering equations are formulated within a symmetry-adapted, single-center expansion of both continuum and bound electrons, and the interaction forces are obtained from a combination of ab initio calculations and a nonempirical model of exchange and correlation effects developed in our group. We present total elastic scattering cross-sections and resonance features obtained for the equilibrium geometries of glycine, alanine, proline and valine. Our results at those geometries of the target molecules are briefly shown to qualitatively explain some of the fragmentation patterns obtained in experiments. We further carry out a one-dimensional (1D) modeling for the dynamics of intramolecular energy transfers mediated by the vibrational activation of selected bonds: our calculations indicate that resonant electron attachment to glycine can trigger direct, dissociative evolution of the complex into (Gly-OH)- and -OH losses, while they also find that the same process does not occur via a direct, 1D dissociative path in the larger amino acids of the present study. (authors)

  3. Complex models of nodal nuclear data

    International Nuclear Information System (INIS)

    Dufek, Jan

    2011-01-01

    During the core simulations, nuclear data are required at various nodal thermal-hydraulic and fuel burnup conditions. The nodal data are also partially affected by thermal-hydraulic and fuel burnup conditions in surrounding nodes as these change the neutron energy spectrum in the node. Therefore, the nodal data are functions of many parameters (state variables), and the more state variables are considered by the nodal data models the more accurate and flexible the models get. The existing table and polynomial regression models, however, cannot reflect the data dependences on many state variables. As for the table models, the number of mesh points (and necessary lattice calculations) grows exponentially with the number of variables. As for the polynomial regression models, the number of possible multivariate polynomials exceeds the limits of existing selection algorithms that should identify a few dozens of the most important polynomials. Also, the standard scheme of lattice calculations is not convenient for modelling the data dependences on various burnup conditions since it performs only a single or few burnup calculations at fixed nominal conditions. We suggest a new efficient algorithm for selecting the most important multivariate polynomials for the polynomial regression models so that dependences on many state variables can be considered. We also present a new scheme for lattice calculations where a large number of burnup histories are accomplished at varied nodal conditions. The number of lattice calculations being performed and the number of polynomials being analysed are controlled and minimised while building the nodal data models of a required accuracy. (author)

  4. Landscape fragmentation and pollinator movement within agricultural environments: a modelling framework for exploring foraging and movement ecology

    Directory of Open Access Journals (Sweden)

    Sean A. Rands

    2014-02-01

    Full Text Available Pollinator decline has been linked to landscape change, through both habitat fragmentation and the loss of habitat suitable for the pollinators to live within. One method for exploring why landscape change should affect pollinator populations is to combine individual-level behavioural ecological techniques with larger-scale landscape ecology. A modelling framework is described that uses spatially-explicit individual-based models to explore the effects of individual behavioural rules within a landscape. The technique described gives a simple method for exploring the effects of the removal of wild corridors, and the creation of wild set-aside fields: interventions that are common to many national agricultural policies. The effects of these manipulations on central-place nesting pollinators are varied, and depend upon the behavioural rules that the pollinators are using to move through the environment. The value of this modelling framework is discussed, and future directions for exploration are identified.

  5. Landscape fragmentation and pollinator movement within agricultural environments: a modelling framework for exploring foraging and movement ecology.

    Science.gov (United States)

    Rands, Sean A

    2014-01-01

    Pollinator decline has been linked to landscape change, through both habitat fragmentation and the loss of habitat suitable for the pollinators to live within. One method for exploring why landscape change should affect pollinator populations is to combine individual-level behavioural ecological techniques with larger-scale landscape ecology. A modelling framework is described that uses spatially-explicit individual-based models to explore the effects of individual behavioural rules within a landscape. The technique described gives a simple method for exploring the effects of the removal of wild corridors, and the creation of wild set-aside fields: interventions that are common to many national agricultural policies. The effects of these manipulations on central-place nesting pollinators are varied, and depend upon the behavioural rules that the pollinators are using to move through the environment. The value of this modelling framework is discussed, and future directions for exploration are identified.

  6. Analysis of proteolytic processes and enzymatic activities in the generation of huntingtin n-terminal fragments in an HEK293 cell model.

    Directory of Open Access Journals (Sweden)

    Andrew T N Tebbenkamp

    Full Text Available N-terminal fragments of mutant huntingtin (htt that terminate between residues 90-115, termed cleavage product A or 1 (cp-A/1, form intracellular and intranuclear inclusion bodies in the brains of patients with Huntington's disease (HD. These fragments appear to be proteolytic products of the full-length protein. Here, we use an HEK293 cell culture model to investigate huntingtin proteolytic processing; previous studies of these cells have demonstrated cleavage of htt to cp-A/1 like htt fragments.Recombinant N-terminal htt fragments, terminating at residue 171 (also referred to as cp-B/2 like, were efficiently cleaved to produce cp-A/1 whereas fragments representing endogenous caspase, calpain, and metalloproteinase cleavage products, terminating between residues 400-600, were inefficiently cleaved. Using cysteine-labeling techniques and antibody binding mapping, we localized the C-terminus of the cp-A/1 fragments produced by HEK293 cells to sequences minimally limited by cysteine 105 and an antibody epitope composed of residues 115-124. A combination of genetic and pharmacologic approaches to inhibit potential proteases, including γ-secretase and calpain, proved ineffective in preventing production of cp-A/1.Our findings indicate that HEK293 cells express a protease that is capable of efficiently cleaving cp-B/2 like fragments of htt with normal or expanded glutamine repeats. For reasons that remain unclear, this protease cleaves longer htt fragments, with normal or expanded glutamine expansions, much less efficiently. The protease in HEK293 cells that is capable of generating a cp-A/1 like htt fragment may be a novel protease with a high preference for a cp-B/2-like htt fragment as substrate.

  7. Algebraic fermion models and nuclear structure physics

    International Nuclear Information System (INIS)

    Troltenier, Dirk; Blokhin, Andrey; Draayer, Jerry P.; Rompf, Dirk; Hirsch, Jorge G.

    1996-01-01

    Recent experimental and theoretical developments are generating renewed interest in the nuclear SU(3) shell model, and this extends to the symplectic model, with its Sp(6,R) symmetry, which is a natural multi-(ℎ/2π)ω extension of the SU(3) theory. First and foremost, an understanding of how the dynamics of a quantum rotor is embedded in the shell model has established it as the model of choice for describing strongly deformed systems. Second, the symplectic model extension of the 0-(ℎ/2π)ω theory can be used to probe additional degrees of freedom, like core polarization and vorticity modes that play a key role in providing a full description of quadrupole collectivity. Third, the discovery and understanding of pseudo-spin has allowed for an extension of the theory from light (A≤40) to heavy (A≥100) nuclei. Fourth, a user-friendly computer code for calculating reduced matrix elements of operators that couple SU(3) representations is now available. And finally, since the theory is designed to cope with deformation in a natural way, microscopic features of deformed systems can be probed; for example, the theory is now being employed to study double beta decay and thereby serves to probe the validity of the standard model of particles and their interactions. A subset of these topics will be considered in this course--examples cited include: a consideration of the origin of pseudo-spin symmetry; a SU(3)-based interpretation of the coupled-rotor model, early results of double beta decay studies; and some recent developments on the pseudo-SU(3) theory. Nothing will be said about other fermion-based theories; students are referred to reviews in the literature for reports on developments in these related areas

  8. Excessive cytosolic DNA fragments as a potential trigger of Graves’ disease: an encrypted message sent by animal models

    Directory of Open Access Journals (Sweden)

    Yuqian Luo

    2016-11-01

    Full Text Available Graves’ hyperthyroidism is caused by autoantibodies directed against the thyroid stimulating hormone receptor (TSHR that mimic the action of TSH. The establishment of Graves’ hyperthyroidism in experimental animals has proven to be an important approach to dissect the mechanisms of self-tolerance breakdown that lead to the production of thyroid-stimulating TSHR autoantibodies (TSAbs. ‘Shimojo’s model was the first successful Graves’ animal model, wherein immunization with fibroblasts cells expressing TSHR and a major histocompatibility complex (MHC class II molecule, but not either alone, induced TSAb production in AKR/N (H-2k mice. This model highlights the importance of coincident MHC class II expression on TSHR-expressing cells in the development of Graves’ hyperthyroidism. These data are also in agreement with the observation that Graves’ thyrocytes often aberrantly express MHC class II antigens via mechanisms that remain unclear. Our group demonstrated that cytosolic self-genomic DNA fragments derived from sterile injured cells can induce aberrant MHC class II expression and production of multiple inflammatory cytokines and chemokines in thyrocytes in vitro, suggesting that severe cell injury may initiate immune responses in a way that is relevant to thyroid autoimmunity mediated by cytosolic DNA signaling. Furthermore, more recent successful Graves’ animal models were primarily established by immunizing mice with TSHR-expressing plasmids or adenovirus. In these models, double-stranded DNA vaccine contents presumably exert similar immune-activating effect in cells at inoculation sites and thus might pave the way toward successful Graves’ animal models. This review focuses on evidence suggesting that cell injury-derived self-DNA fragments could act as Graves’ disease triggers.

  9. Scission-point model of nuclear fission based on deformed-shell effects

    International Nuclear Information System (INIS)

    Wilkins, B.D.; Steinberg, E.P.; Chasman, R.R.

    1976-01-01

    A static model of nuclear fission is proposed based on the assumption of statistical equilibrium among collective degrees of freedom at the scission point. The relative probabilities of formation of complementary fission fragment pairs are determined from the relative potential energies of a system of two nearly touching, coaxial spheroids with quadrupole deformations. The total potential energy of the system at the scission point is calculated as the sum of liquid-drop and shell- and pairing-correction terms for each spheroid, and Coulomb and nuclear potential terms describing the interaction between them. The fissioning system at the scission point is characterized by three parameters: the distance between the tips of the spheroids (d), the intrinsic excitation energy of the fragments (tau/sub int/), and a collective temperature (T/sub coll/). No attempt is made to adjust these parameters to give optimum fits to experimental data, but rather, a single choice of values for d, tau/sub int/, and T/sub coll/ is used in the calculations for all fissioning systems. The general trends of the distributions of mass, nuclear charge, and kinetic energy in the fission of a wide range of nuclides from Po to Fm are well reproduced in the calculations. The major influence of the deformed-shell corrections for neutrons is indicated and provides a convenient framework for the interpretation of observed trends in the data and for the prediction of new results. The scission-point configurations derived from the model provide an interpretation of the ''saw-tooth'' neutron emission curve as well as previously unexplained observations on the variation of TKE for isotopes of U, Pu, Cm, and Cf; structure in the width of total kinetic energy release as a function of fragment mass ratio; and a difference in threshold energies for symmetric and asymmetric mass splits in the fission of Ra and Ac isotopes

  10. Comparison of models of high energy nuclear collisions

    International Nuclear Information System (INIS)

    Gyulassy, M.

    1978-01-01

    The treatment of high energy nuclear reaction models covers goals of such collisions, the choice of theoretical framework, the zoo of models (p inclusive), light composites, models versus experiment, conclusions drawn, needed experiments, and pion production. 30 diagrams

  11. Microstructural modelling of nuclear graphite using multi-phase models

    International Nuclear Information System (INIS)

    Berre, C.; Fok, S.L.; Marsden, B.J.; Mummery, P.M.; Marrow, T.J.; Neighbour, G.B.

    2008-01-01

    This paper presents a new modelling technique using three-dimensional multi-phase finite element models in which meshes representing the microstructure of thermally oxidised nuclear graphite were generated from X-ray micro-tomography images. The density of the material was related to the image greyscale using Beer-Lambert's law, and multiple phases could thus be defined. The local elastic and non-linear properties of each phase were defined as a function of density and changes in Young's modulus, tensile and compressive strength with thermal oxidation were calculated. Numerical predictions compared well with experimental data and with other numerical results obtained using two-phase models. These models were found to be more representative of the actual microstructure of the scanned material than two-phase models and, possibly because of pore closure occurring during compression, compressive tests were also predicted to be less sensitive to the microstructure geometry than tensile tests

  12. Dynamic effects in fragmentation reactions

    International Nuclear Information System (INIS)

    Bertsch, G. F.; Esbensen, H.

    2002-01-01

    Fragmentation reactions offer a useful tool to study the spectroscopy of halo nuclei, but the large extent of the halo wave function makes the reaction theory more difficult. The simple reaction models based on the eikonal approximation for the nuclear interaction or first-order perturbation theory for the Coulomb interaction have systematic errors that they investigate here, comparing to the predictions of complete dynamical calculations. They find that stripping probabilities are underpredicted by the eikonal model, leading to extracted spectroscopy strengths that are two large. In contrast, the Coulomb excitation is overpredicted by the simple theory. They attribute this to a screening effect, as is well known in the Barkas effect on stopping powers. The errors decrease with beam energy as E(sub beam)(sup -1), and are not significant at beam energies above 50 MeV/u. At lower beam energies, the effects should be taken into account when extracting quantitative spectroscopic strengths

  13. String fragmentation; La fragmentation des cordes

    Energy Technology Data Exchange (ETDEWEB)

    Drescher, H.J.; Werner, K. [Laboratoire de Physique Subatomique et des Technologies Associees - SUBATECH, Centre National de la Recherche Scientifique, 44 - Nantes (France)

    1997-10-01

    The classical string model is used in VENUS as a fragmentation model. For the soft domain simple 2-parton strings were sufficient, whereas for higher energies up to LHC, the perturbative regime of the QCD gives additional soft gluons, which are mapped on the string as so called kinks, energy singularities between the leading partons. The kinky string model is chosen to handle fragmentation of these strings by application of the Lorentz invariant area law. The `kinky strings` model, corresponding to the perturbative gluons coming from pQCD, takes into consideration this effect by treating the partons and gluons on the same footing. The decay law is always the Artru-Menessier area law which is the most realistic since it is invariant to the Lorentz and gauge transformations. For low mass strings a manipulation of the rupture point is necessary if the string corresponds already to an elementary particle determined by the mass and the flavor content. By means of the fragmentation model it will be possible to simulate the data from future experiments at LHC and RHIC 3 refs.

  14. Mathematical model use for evaluation of radioactivity spreading in nuclear power plant

    International Nuclear Information System (INIS)

    Kubik, I.; Gladki, Eh.; Yanchik, O.

    1976-01-01

    On the basis of knowledges of radioactive products behaviour and their spreading in nuclear power plant under normal and accident conditions a KOMPLEX program is developed in the FORTRAN 4 language, permitting to calculate the activity in separate parts of the nuclear power plant with WWR type reactor. The COMPLEX program includes the following subprograms: AZ - PRIM - for estimating active products in fuel, coolant, on the surfaces of fuel element cans and the primary circuit. The subprogram permits to estimate the coolant activity at the expense of fission fragments for 4 different leakage mechanisms: due to diffusion, considerable fuel element damage, contamination of fuel element can surface and fuel washout by coolant; KOR - the program for estimating active corrosion products; ACT - the program for estimating the activity of activation products; CONT - the program for estimating the activity in the nuclear power plant premises (protection envelop) and ventilating pipe. The desciption of the above subprograms is given. For testing of the mathematical model applicability and the possibilities of the corresponding programs the checking calculations for operating parameters of nuclear power plant with WWR type reactor were carried out. The calculation results obtained have shown the applicability of the model suggested and the corresponding programes for nuclear power plant under normal operation and accident conditions [ru

  15. Embedding Fragment ab Initio Model Potentials in CASSCF/CASPT2 Calculations of Doped Solids: Implementation and Applications.

    Science.gov (United States)

    Swerts, Ben; Chibotaru, Liviu F; Lindh, Roland; Seijo, Luis; Barandiaran, Zoila; Clima, Sergiu; Pierloot, Kristin; Hendrickx, Marc F A

    2008-04-01

    In this article, we present a fragment model potential approach for the description of the crystalline environment as an extension of the use of embedding ab initio model potentials (AIMPs). The biggest limitation of the embedding AIMP method is the spherical nature of its model potentials. This poses problems as soon as the method is applied to crystals containing strongly covalently bonded structures with highly nonspherical electron densities. The newly proposed method addresses this problem by keeping the full electron density as its model potential, thus allowing one to group sets of covalently bonded atoms into fragments. The implementation in the MOLCAS 7.0 quantum chemistry package of the new method, which we call the embedding fragment ab inito model potential method (embedding FAIMP), is reported here, together with results of CASSCF/CASPT2 calculations. The developed methodology is applied for two test problems: (i) the investigation of the lowest ligand field states (2)A1 and (2)B1 of the Cr(V) defect in the YVO4 crystal and (ii) the investigation of the lowest ligand field and ligand-metal charge transfer (LMCT) states at the Mn(II) substitutional impurity doped into CaCO3. Comparison with similar calculations involving AIMPs for all environmental atoms, including those from covalently bounded units, shows that the FAIMP treatment of the YVO4 units surrounding the CrO4(3-) cluster increases the excitation energy (2)B1 → (2)A1 by ca. 1000 cm(-1) at the CASSCF level of calculation. In the case of the Mn(CO3)6(10-) cluster, the FAIMP treatment of the CO3(2-) units of the environment give smaller corrections, of ca. 100 cm(-1), for the ligand-field excitation energies, which is explained by the larger ligands of this cluster. However, the correction for the energy of the lowest LMCT transition is found to be ca. 600 cm(-1) for the CASSCF and ca. 1300 cm(-1) for the CASPT2 calculation.

  16. Theoretical modelling of nuclear waste flows - 16377

    International Nuclear Information System (INIS)

    Adams, J.F.; Biggs, S.R.; Fairweather, M.; Njobuenwu, D.; Yao, J.

    2009-01-01

    A large amount of nuclear waste is stored in tailings ponds as a solid-liquid slurry, and liquid flows containing suspensions of solid particles are encountered in the treatment and disposal of this waste. In processing this waste, it is important to understand the behaviour of particles within the flow in terms of their settling characteristics, their propensity to form solid beds, and the re-suspension characteristics of particles from a bed. A clearer understanding of such behaviour would allow the refinement of current approaches to waste management, potentially leading to reduced uncertainties in radiological impact assessments, smaller waste volumes and lower costs, accelerated clean-up, reduced worker doses, enhanced public confidence and diminished grounds for objection to waste disposal. Mathematical models are of significant value in nuclear waste processing since the extent of characterisation of wastes is in general low. Additionally, waste processing involves a diverse range of flows, within vessels, ponds and pipes. To investigate experimentally all waste form characteristics and potential flows of interest would be prohibitively expensive, whereas the use of mathematical models can help to focus experimental studies through the more efficient use of existing data, the identification of data requirements, and a reduction in the need for process optimisation in full-scale experimental trials. Validated models can also be used to predict waste transport behaviour to enable cost effective process design and continued operation, to provide input to process selection, and to allow the prediction of operational boundaries that account for the different types and compositions of particulate wastes. In this paper two mathematical modelling techniques, namely Reynolds-averaged Navier-Stokes (RANS) and large eddy simulation (LES), have been used to investigate particle-laden flows in a straight square duct and a duct with a bend. The flow solutions provided by

  17. Modeling a nuclear reactor for experimental purposes

    International Nuclear Information System (INIS)

    Berta, V.T.

    1980-01-01

    The Loss-of-Fluid Test (LOFT) Facility is a scale model of a commercial PWR and is as fully functional and operational as the generic commercial counterpart. LOFT was designed and built for experimental purposes as part of the overall NRC reactor safety research program. The purpose of LOFT is to assess the capability of reactor safety systems to perform their intended functions during occurrences of off-normal conditions in a commercial nuclear reactor. Off-normal conditions arising from large and small break loss-of-coolant accidents (LOCA), operational transients, and anticipated transients without scram (ATWS) were to be investigated. This paper describes the LOFT model of the generic PWR and summarizes the experiments that have been conducted in the context of the significant findings involving the complex transient thermal-hydraulics and the consequent effects on the commercial reactor analytical licensing techniques. Through these techniques the validity of the LOFT model as a scaled counterpart of the generic PWR is shown

  18. Centrifugal fragmentation of a dinuclear system in the process of its evolution to the compound nucleus

    International Nuclear Information System (INIS)

    Volkov, V.V.

    2005-01-01

    The physical content of centrifugal fragmentation is discussed. It is a specific nuclear process which is realized in the evolution of a dinuclear system into a compound nucleus at large angular momenta and large mass asymmetry of the system. The dinuclear system concept which describes the process of the compound nucleus formation in heavy ion reactions predicts the possibility of centrifugal fragmentation. Experimental data giving evidence of the realization of this nuclear process are given. A possible scheme of the centrifugal fragmentation model is discussed

  19. Centrifugal Fragmentation of a Dinuclear System in the Process of Its Evolution to the Compound Nucleus

    CERN Document Server

    Volkov, V V

    2005-01-01

    The physical content of centrifugal fragmentation is discussed. It is a specific nuclear process which is realized in the evolution of a dinuclear system into a compound nucleus at large angular momenta and large mass asymmetry of the system. The dinuclear system concept which describes the process of the compound nucleus formation in heavy ion reactions predicts the possibility of centrifugal fragmentation. Experimental data giving evidence of the realization of this nuclear process are given. A possible scheme of the centrifugal fragmentation model is discussed.

  20. PELE fragmentation dynamics

    NARCIS (Netherlands)

    Verreault, J.; Hinsberg, N.P. van; Abadjieva, E.

    2013-01-01

    An analytical model that describes the PELE fragmentation dynamics is presented and compared with experimental results from literature. The model accounts for strong shock effects and detailed interactions taking place between the filling – the inner core of the ammunition – and the target

  1. A model for consecutive spallation and fragmentation reactions in inverse kinematics at relativistic energies

    International Nuclear Information System (INIS)

    Napolitani, P.; Tassan-Got, L.; Bernas, M.; Armbruster, P.

    2003-04-01

    Secondary reactions induced by relativistic beams in inverse kinematics in a thick target are relevant in several fields of experimental physics and technology, like secondary radioactive beams, production of exotic nuclei close to the proton drip line, and cross-section measurements for applications of spallation reactions for energy production and incineration of nuclear wastes. A general mathematical formulation is presented and successively applied as a tool to disentangle the primary reaction yields from the secondary production in the measurement of fission of a 238 U projectile impinging on a proton target at the energy of 1 A GeV. (orig.)

  2. Fragment-based lead generation: identification of seed fragments by a highly efficient fragment screening technology

    Science.gov (United States)

    Neumann, Lars; Ritscher, Allegra; Müller, Gerhard; Hafenbradl, Doris

    2009-08-01

    For the detection of the precise and unambiguous binding of fragments to a specific binding site on the target protein, we have developed a novel reporter displacement binding assay technology. The application of this technology for the fragment screening as well as the fragment evolution process with a specific modelling based design strategy is demonstrated for inhibitors of the protein kinase p38alpha. In a fragment screening approach seed fragments were identified which were then used to build compounds from the deep-pocket towards the hinge binding area of the protein kinase p38alpha based on a modelling approach. BIRB796 was used as a blueprint for the alignment of the fragments. The fragment evolution of these deep-pocket binding fragments towards the fully optimized inhibitor BIRB796 included the modulation of the residence time as well as the affinity. The goal of our study was to evaluate the robustness and efficiency of our novel fragment screening technology at high fragment concentrations, compare the screening data with biochemical activity data and to demonstrate the evolution of the hit fragments with fast kinetics, into slow kinetic inhibitors in an in silico approach.

  3. Dynameomics: Data-driven methods and models for utilizing large-scale protein structure repositories for improving fragment-based loop prediction

    Science.gov (United States)

    Rysavy, Steven J; Beck, David AC; Daggett, Valerie

    2014-01-01

    Protein function is intimately linked to protein structure and dynamics yet experimentally determined structures frequently omit regions within a protein due to indeterminate data, which is often due protein dynamics. We propose that atomistic molecular dynamics simulations provide a diverse sampling of biologically relevant structures for these missing segments (and beyond) to improve structural modeling and structure prediction. Here we make use of the Dynameomics data warehouse, which contains simulations of representatives of essentially all known protein folds. We developed novel computational methods to efficiently identify, rank and retrieve small peptide structures, or fragments, from this database. We also created a novel data model to analyze and compare large repositories of structural data, such as contained within the Protein Data Bank and the Dynameomics data warehouse. Our evaluation compares these structural repositories for improving loop predictions and analyzes the utility of our methods and models. Using a standard set of loop structures, containing 510 loops, 30 for each loop length from 4 to 20 residues, we find that the inclusion of Dynameomics structures in fragment-based methods improves the quality of the loop predictions without being dependent on sequence homology. Depending on loop length, ∼25–75% of the best predictions came from the Dynameomics set, resulting in lower main chain root-mean-square deviations for all fragment lengths using the combined fragment library. We also provide specific cases where Dynameomics fragments provide better predictions for NMR loop structures than fragments from crystal structures. Online access to these fragment libraries is available at http://www.dynameomics.org/fragments. PMID:25142412

  4. Dynameomics: data-driven methods and models for utilizing large-scale protein structure repositories for improving fragment-based loop prediction.

    Science.gov (United States)

    Rysavy, Steven J; Beck, David A C; Daggett, Valerie

    2014-11-01

    Protein function is intimately linked to protein structure and dynamics yet experimentally determined structures frequently omit regions within a protein due to indeterminate data, which is often due protein dynamics. We propose that atomistic molecular dynamics simulations provide a diverse sampling of biologically relevant structures for these missing segments (and beyond) to improve structural modeling and structure prediction. Here we make use of the Dynameomics data warehouse, which contains simulations of representatives of essentially all known protein folds. We developed novel computational methods to efficiently identify, rank and retrieve small peptide structures, or fragments, from this database. We also created a novel data model to analyze and compare large repositories of structural data, such as contained within the Protein Data Bank and the Dynameomics data warehouse. Our evaluation compares these structural repositories for improving loop predictions and analyzes the utility of our methods and models. Using a standard set of loop structures, containing 510 loops, 30 for each loop length from 4 to 20 residues, we find that the inclusion of Dynameomics structures in fragment-based methods improves the quality of the loop predictions without being dependent on sequence homology. Depending on loop length, ∼ 25-75% of the best predictions came from the Dynameomics set, resulting in lower main chain root-mean-square deviations for all fragment lengths using the combined fragment library. We also provide specific cases where Dynameomics fragments provide better predictions for NMR loop structures than fragments from crystal structures. Online access to these fragment libraries is available at http://www.dynameomics.org/fragments. © 2014 The Protein Society.

  5. Asymmetric nuclear matter in a modified quark meson coupling model

    International Nuclear Information System (INIS)

    Mishra, R.N.; Sahoo, H.S.; Panda, P.K.; Barik, N.

    2014-01-01

    In an earlier attempt we have successfully used this model in developing the nuclear equation of state and analysed various other bulk properties of symmetric nuclear matter with the dependence of quark masses. In the present work we want to apply the model to analyze asymmetric nuclear matter with the variation of the asymmetry parameter y p as well as analyze the effects of symmetry energy and the slope of the symmetry energy L

  6. Tuning and Test of Fragmentation Models Based on Identified Particles and Precision Event Shape Data

    CERN Document Server

    Abreu, P; Adye, T; Ajinenko, I; Alekseev, G D; Alemany, R; Allport, P P; Almehed, S; Amaldi, Ugo; Amato, S; Andreazza, A; Andrieux, M L; Antilogus, P; Apel, W D; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Bambade, P; Barão, F; Barate, R; Barbi, M S; Bardin, Dimitri Yuri; Baroncelli, A; Bärring, O; Barrio, J A; Bartl, Walter; Bates, M J; Battaglia, Marco; Baubillier, M; Baudot, J; Becks, K H; Begalli, M; Beillière, P; Belokopytov, Yu A; Belous, K S; Benvenuti, Alberto C; Berggren, M; Bertini, D; Bertrand, D; Besançon, M; Bianchi, F; Bigi, M; Bilenky, S M; Billoir, P; Bloch, D; Blume, M; Bolognese, T; Bonesini, M; Bonivento, W; Booth, P S L; Bosio, C; Botner, O; Boudinov, E; Bouquet, B; Bourdarios, C; Bowcock, T J V; Bozzo, M; Branchini, P; Brand, K D; Brenke, T; Brenner, R A; Bricman, C; Brown, R C A; Brückman, P; Brunet, J M; Bugge, L; Buran, T; Burgsmüller, T; Buschmann, P; Buys, A; Cabrera, S; Caccia, M; Calvi, M; Camacho-Rozas, A J; Camporesi, T; Canale, V; Canepa, M; Cankocak, K; Cao, F; Carena, F; Carroll, L; Caso, Carlo; Castillo-Gimenez, M V; Cattai, A; Cavallo, F R; Chabaud, V; Charpentier, P; Chaussard, L; Checchia, P; Chelkov, G A; Chen, M; Chierici, R; Chliapnikov, P V; Chochula, P; Chorowicz, V; Chudoba, J; Cindro, V; Collins, P; Contreras, J L; Contri, R; Cortina, E; Cosme, G; Cossutti, F; Cowell, J H; Crawley, H B; Crennell, D J; Crosetti, G; Cuevas-Maestro, J; Czellar, S; Dahl-Jensen, Erik; Dahm, J; D'Almagne, B; Dam, M; Damgaard, G; Dauncey, P D; Davenport, Martyn; Da Silva, W; Defoix, C; Deghorain, A; Della Ricca, G; Delpierre, P A; Demaria, N; De Angelis, A; de Boer, Wim; De Brabandere, S; De Clercq, C; La Vaissière, C de; De Lotto, B; De Min, A; De Paula, L S; De Saint-Jean, C; Dijkstra, H; Di Ciaccio, Lucia; Di Diodato, A; Djama, F; Dolbeau, J; Dönszelmann, M; Doroba, K; Dracos, M; Drees, J; Drees, K A; Dris, M; Durand, J D; Edsall, D M; Ehret, R; Eigen, G; Ekelöf, T J C; Ekspong, Gösta; Elsing, M; Engel, J P; Erzen, B; Espirito-Santo, M C; Falk, E; Fassouliotis, D; Feindt, Michael; Ferrer, A; Fichet, S; Filippas-Tassos, A; Firestone, A; Fischer, P A; Föth, H; Fokitis, E; Fontanelli, F; Formenti, F; Franek, B J; Frenkiel, P; Fries, D E C; Frodesen, A G; Frühwirth, R; Fulda-Quenzer, F; Fuster, J A; Galloni, A; Gamba, D; Gandelman, M; García, C; García, J; Gaspar, C; Gasparini, U; Gavillet, P; Gazis, E N; Gelé, D; Gerber, J P; Gokieli, R; Golob, B; Gopal, Gian P; Gorn, L; Górski, M; Guz, Yu; Gracco, Valerio; Graziani, E; Green, C; Grefrath, A; Gris, P; Grosdidier, G; Grzelak, K; Gumenyuk, S A; Gunnarsson, P; Günther, M; Guy, J; Hahn, F; Hahn, S; Hajduk, Z; Hallgren, A; Hamacher, K; Harris, F J; Hedberg, V; Henriques, R P; Hernández, J J; Herquet, P; Herr, H; Hessing, T L; Higón, E; Hilke, Hans Jürgen; Hill, T S; Holmgren, S O; Holt, P J; Holthuizen, D J; Hoorelbeke, S; Houlden, M A; Hrubec, Josef; Huet, K; Hultqvist, K; Jackson, J N; Jacobsson, R; Jalocha, P; Janik, R; Jarlskog, C; Jarlskog, G; Jarry, P; Jean-Marie, B; Johansson, E K; Jönsson, L B; Jönsson, P E; Joram, Christian; Juillot, P; Kaiser, M; Kapusta, F; Karafasoulis, K; Karlsson, M; Karvelas, E; Katsanevas, S; Katsoufis, E C; Keränen, R; Khokhlov, Yu A; Khomenko, B A; Khovanskii, N N; King, B J; Kjaer, N J; Klapp, O; Klein, H; Klovning, A; Kluit, P M; Köne, B; Kokkinias, P; Koratzinos, M; Korcyl, K; Kostyukhin, V; Kourkoumelis, C; Kuznetsov, O; Kreuter, C; Kronkvist, I J; Krumshtein, Z; Krupinski, W; Kubinec, P; Kucewicz, W; Kurvinen, K L; Lacasta, C; Laktineh, I; Lamsa, J; Lanceri, L; Lane, D W; Langefeld, P; Lapin, V; Laugier, J P; Lauhakangas, R; Leder, Gerhard; Ledroit, F; Lefébure, V; Legan, C K; Leitner, R; Lemonne, J; Lenzen, Georg; Lepeltier, V; Lesiak, T; Libby, J; Liko, D; Lindner, R; Lipniacka, A; Lippi, I; Lörstad, B; Loken, J G; López, J M; Loukas, D; Lutz, P; Lyons, L; Naughton, J M; Maehlum, G; Mahon, J R; Maio, A; Malmgren, T G M; Malychev, V; Mandl, F; Marco, J; Marco, R P; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Martínez-Rivero, C; Martínez-Vidal, F; Martí i García, S; Masik, J; Matorras, F; Matteuzzi, C; Matthiae, Giorgio; Mazzucato, M; McCubbin, M L; McKay, R; McNulty, R; Medbo, J; Merk, M; Meroni, C; Meyer, S; Meyer, W T; Myagkov, A; Michelotto, M; Migliore, E; Mirabito, L; Mitaroff, Winfried A; Mjörnmark, U; Moa, T; Møller, R; Mönig, K; Monge, M R; Morettini, P; Müller, H; Mulders, M; Mundim, L M; Murray, W J; Muryn, B; Myatt, Gerald; Naraghi, F; Navarria, Francesco Luigi; Navas, S; Nawrocki, K; Negri, P; Neumann, W; Neumeister, N; Nicolaidou, R; Nielsen, B S; Nieuwenhuizen, M; Nikolaenko, V; Niss, P; Nomerotski, A; Normand, Ainsley; Oberschulte-Beckmann, W; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Österberg, K; Ouraou, A; Paganini, P; Paganoni, M; Pagès, P; Pain, R; Palka, H; Papadopoulou, T D; Papageorgiou, K; Pape, L; Parkes, C; Parodi, F; Passeri, A; Pegoraro, M; Peralta, L; Pernegger, H; Pernicka, Manfred; Perrotta, A; Petridou, C; Petrolini, A; Petrovykh, M; Phillips, H T; Piana, G; Pierre, F; Plaszczynski, S; Podobrin, O; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Privitera, P; Pukhaeva, N; Pullia, Antonio; Radojicic, D; Ragazzi, S; Rahmani, H; Rames, J; Ratoff, P N; Read, A L; Reale, M; Rebecchi, P; Redaelli, N G; Regler, Meinhard; Reid, D; Renton, P B; Resvanis, L K; Richard, F; Richardson, J; Rídky, J; Rinaudo, G; Ripp, I; Romero, A; Roncagliolo, I; Ronchese, P; Roos, L; Rosenberg, E I; Rosso, E; Roudeau, Patrick; Rovelli, T; Rückstuhl, W; Ruhlmann-Kleider, V; Ruiz, A; Rybicki, K; Saarikko, H; Sacquin, Yu; Sadovskii, A; Sahr, O; Sajot, G; Salt, J; Sánchez, J; Sannino, M; Schimmelpfennig, M; Schneider, H; Schwickerath, U; Schyns, M A E; Sciolla, G; Scuri, F; Seager, P; Sedykh, Yu; Segar, A M; Seitz, A; Sekulin, R L; Serbelloni, L; Shellard, R C; Siegrist, P; Silvestre, R; Simonetti, S; Simonetto, F; Sissakian, A N; Sitár, B; Skaali, T B; Smadja, G; Smirnov, N; Smirnova, O G; Smith, G R; Sokolov, A; Sosnowski, R; Souza-Santos, D; Spassoff, Tz; Spiriti, E; Sponholz, P; Squarcia, S; Stanescu, C; Stapnes, Steinar; Stavitski, I; Stevenson, K; Stichelbaut, F; Stocchi, A; Strauss, J; Strub, R; Stugu, B; Szczekowski, M; Szeptycka, M; Tabarelli de Fatis, T; Tavernet, J P; Chikilev, O G; Thomas, J; Tilquin, A; Timmermans, J; Tkatchev, L G; Todorov, T; Todorova, S; Toet, D Z; Tomaradze, A G; Tomé, B; Tonazzo, A; Tortora, L; Tranströmer, G; Treille, D; Trischuk, W; Tristram, G; Trombini, A; Troncon, C; Tsirou, A L; Turluer, M L; Tyapkin, I A; Tyndel, M; Tzamarias, S; Überschär, B; Ullaland, O; Uvarov, V; Valenti, G; Vallazza, E; van Apeldoorn, G W; van Dam, P; Van Eldik, J; Vassilopoulos, N; Vegni, G; Ventura, L; Venus, W A; Verbeure, F; Verlato, M; Vertogradov, L S; Vilanova, D; Vincent, P; Vitale, L; Vlasov, E; Vodopyanov, A S; Vrba, V; Wahlen, H; Walck, C; Waldner, F; Weierstall, M; Weilhammer, Peter; Weiser, C; Wetherell, Alan M; Wicke, D; Wickens, J H; Wielers, M; Wilkinson, G R; Williams, W S C; Winter, M; Witek, M; Woschnagg, K; Yip, K; Yushchenko, O P; Zach, F; Zaitsev, A; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zevgolatakos, E; Zimin, N I; Zito, M; Zontar, D; Zucchelli, G C; Zumerle, G

    1996-01-01

    Event shape and charged particle inclusive distributions are measured using 750000 decays of the $Z$ to hadrons from the DELPHI detector at LEP. These precise data allow a decisive confrontation with models of the hadronization process. Improved tunings of the JETSET ARIADNE and HERWIG parton shower models and the JETSET matrix element model are obtained by fitting the models to these DELPHI data as well as to identified particle distributions from all LEP experiments. The description of the data distributions by the models is critically reviewed with special importance attributed to identified particles.

  7. Intermediate Fragment

    DEFF Research Database (Denmark)

    Kruse Aagaard, Anders

    2015-01-01

    This text and its connected exhibition are aiming to reflect both on the thoughts, the processes and the outcome of the design and production of the artefact ‘Intermediate Fragment’ and making as a contemporary architectural tool in general. Intermediate Fragment was made for the exhibition ‘Enga...... of realising an exhibition object was conceived, but expanded, refined and concretised through this process. The context of the work shown here is an interest in a tighter, deeper connection between experimentally obtained material knowledge and architectural design....

  8. Fragmentation based

    Directory of Open Access Journals (Sweden)

    Shashank Srivastava

    2014-01-01

    Gaining the understanding of mobile agent architecture and the security concerns, in this paper, we proposed a security protocol which addresses security with mitigated computational cost. The protocol is a combination of self decryption, co-operation and obfuscation technique. To circumvent the risk of malicious code execution in attacking environment, we have proposed fragmentation based encryption technique. Our encryption technique suits the general mobile agent size and provides hard and thorny obfuscation increasing attacker’s challenge on the same plane providing better performance with respect to computational cost as compared to existing AES encryption.

  9. Bespoke Fragments

    DEFF Research Database (Denmark)

    Kruse Aagaard, Anders

    2016-01-01

    , investigating levels of control and uncertainty encountering with these. Through tangible experiments, the project discusses materiality and digitally controlled fabrications tools as direct expansions of the architect's digital drawing and workflow. The project sees this expansion as an opportunity to connect...... architectural designs, tectonics and aesthetics. In this Ph.D.-project a series a physical, but conceptual, experiment plays the central role in the knowledge production. The experiments result in materialised architectural fragments and tangible experiences. However, these creations also become the driving...

  10. Inhibiting α-synuclein oligomerization by stable cell-penetrating β-synuclein fragments recovers phenotype of Parkinson's disease model flies.

    Directory of Open Access Journals (Sweden)

    Ronit Shaltiel-Karyo

    Full Text Available The intracellular oligomerization of α-synuclein is associated with Parkinson's disease and appears to be an important target for disease-modifying treatment. Yet, to date, there is no specific inhibitor for this aggregation process. Using unbiased systematic peptide array analysis, we identified molecular interaction domains within the β-synuclein polypeptide that specifically binds α-synuclein. Adding such peptide fragments to α-synuclein significantly reduced both amyloid fibrils and soluble oligomer formation in vitro. A retro-inverso analogue of the best peptide inhibitor was designed to develop the identified molecular recognition module into a drug candidate. While this peptide shows indistinguishable activity as compared to the native peptide, it is stable in mouse serum and penetrates α-synuclein over-expressing cells. The interaction interface between the D-amino acid peptide and α-synuclein was mapped by Nuclear Magnetic Resonance spectroscopy. Finally, administering the retro-inverso peptide to a Drosophila model expressing mutant A53T α-synuclein in the nervous system, resulted in a significant recovery of the behavioral abnormalities of the treated flies and in a significant reduction in α-synuclein accumulation in the brains of the flies. The engineered retro-inverso peptide can serve as a lead for developing a novel class of therapeutic agents to treat Parkinson's disease.

  11. Stochastic processes analysis in nuclear reactor using ARMA models

    International Nuclear Information System (INIS)

    Zavaljevski, N.

    1990-01-01

    The analysis of ARMA model derived from general stochastic state equations of nuclear reactor is given. The dependence of ARMA model parameters on the main physical characteristics of RB nuclear reactor in Vinca is presented. Preliminary identification results are presented, observed discrepancies between theory and experiment are explained and the possibilities of identification improvement are anticipated. (author)

  12. From pair correlations to the quasi-particle-phonon nuclear model

    International Nuclear Information System (INIS)

    Solov'ev, V.G.

    1986-01-01

    Modern state of the nucleus theory is discussed. The main attention is paid to pair correlation theory of superconducting type and quasiparticle - phonon nucleus model. Pair correlation account allowed one to describe in detail a series of nucleus properties which did not fall within the framework of earlier known models as, for example, double-quasi-particle states in even-even deformed nuclei. To describe the wave function low-quasi-particle components at low, mean and high excitation energies, the nucleus quasi-particle-phonon model is formulated. The strength function method is used in the model and fragmentation of mono-quasi-particle, mono-phonon states and quasi-particle phonon state by many nuclear levels is calculated

  13. A fermionic molecular dynamics technique to model nuclear matter

    International Nuclear Information System (INIS)

    Vantournhout, K.; Jachowicz, N.; Ryckebusch, J.

    2009-01-01

    Full text: At sub-nuclear densities of about 10 14 g/cm 3 , nuclear matter arranges itself in a variety of complex shapes. This can be the case in the crust of neutron stars and in core-collapse supernovae. These slab like and rod like structures, designated as nuclear pasta, have been modelled with classical molecular dynamics techniques. We present a technique, based on fermionic molecular dynamics, to model nuclear matter at sub-nuclear densities in a semi classical framework. The dynamical evolution of an antisymmetric ground state is described making the assumption of periodic boundary conditions. Adding the concepts of antisymmetry, spin and probability distributions to classical molecular dynamics, brings the dynamical description of nuclear matter to a quantum mechanical level. Applications of this model vary from investigation of macroscopic observables and the equation of state to the study of fundamental interactions on the microscopic structure of the matter. (author)

  14. Modelling human resource requirements for the nuclear industry in Europe

    Energy Technology Data Exchange (ETDEWEB)

    Roelofs, Ferry [Nuclear Research and Consultancy Group (NRG) (Netherlands); Flore, Massimo; Estorff, Ulrik von [Joint Research Center (JRC) (Netherlands)

    2017-11-15

    The European Human Resource Observatory for Nuclear (EHRO-N) provides the European Commission with essential data related to supply and demand for nuclear experts in the EU-28 and the enlargement and integration countries based on bottom-up information from the nuclear industry. The objective is to assess how the supply of experts for the nuclear industry responds to the needs for the same experts for present and future nuclear projects in the region. Complementary to the bottom-up approach taken by the EHRO-N team at JRC, a top-down modelling approach has been taken in a collaboration with NRG in the Netherlands. This top-down modelling approach focuses on the human resource requirements for operation, construction, decommissioning, and efforts for long term operation of nuclear power plants. This paper describes the top-down methodology, the model input, the main assumptions, and the results of the analyses.

  15. Experiment research on cognition reliability model of nuclear power plant

    International Nuclear Information System (INIS)

    Zhao Bingquan; Fang Xiang

    1999-01-01

    The objective of the paper is to improve the reliability of operation on real nuclear power plant of operators through the simulation research to the cognition reliability of nuclear power plant operators. The research method of the paper is to make use of simulator of nuclear power plant as research platform, to take present international research model of reliability of human cognition based on three-parameter Weibull distribution for reference, to develop and get the research model of Chinese nuclear power plant operators based on two-parameter Weibull distribution. By making use of two-parameter Weibull distribution research model of cognition reliability, the experiments about the cognition reliability of nuclear power plant operators have been done. Compared with the results of other countries such USA and Hungary, the same results can be obtained, which can do good to the safety operation of nuclear power plant

  16. Modelling human resource requirements for the nuclear industry in Europe

    International Nuclear Information System (INIS)

    Roelofs, Ferry; Flore, Massimo; Estorff, Ulrik von

    2017-01-01

    The European Human Resource Observatory for Nuclear (EHRO-N) provides the European Commission with essential data related to supply and demand for nuclear experts in the EU-28 and the enlargement and integration countries based on bottom-up information from the nuclear industry. The objective is to assess how the supply of experts for the nuclear industry responds to the needs for the same experts for present and future nuclear projects in the region. Complementary to the bottom-up approach taken by the EHRO-N team at JRC, a top-down modelling approach has been taken in a collaboration with NRG in the Netherlands. This top-down modelling approach focuses on the human resource requirements for operation, construction, decommissioning, and efforts for long term operation of nuclear power plants. This paper describes the top-down methodology, the model input, the main assumptions, and the results of the analyses.

  17. On the long standing question of nuclear track etch induction time: Surface-cap model

    International Nuclear Information System (INIS)

    Rana, Mukhtar Ahmed

    2008-01-01

    Using a systematic set of experiments, nuclear track etch induction time measurements in a widely used CR-39 detector were completed for accessible track-forming particles (fission fragments, 5.2 MeV alpha particles and 5.9 MeV antiprotons). Results of the present work are compared with appropriately selected published results. The possibility of the use of etch induction time for charged particle identification is evaluated. Analysis of experimental results along with the use of well-established theoretical concepts yielded a model about delay in the start of chemical etching of nuclear tracks. The suggested model proposes the formation of a surface-cap (top segment) in each nuclear track consisting of chemically modified material with almost same or even higher resistance to chemical etching compared with bulk material of the track detector. Existing track formation models are reviewed very briefly, which provide one of the two bases of the proposed model. The other basis of the model is the general behavior of hot or energised material having a connection with an environment containing a number of species like ordinary air. Another reason for the delay in the start of etching is suggested as the absence of localization of etching atoms/molecules, which is present during etching at depth along the latent track

  18. Influence of spin on fission fragments anisotropy

    Directory of Open Access Journals (Sweden)

    Ghodsi Omid N.

    2005-01-01

    Full Text Available An analysis of selected fission fragment angular distribution when at least one of the spins of the projectile or target is appreciable in induced fission was made by using the statistical scission model. The results of this model predicate that the spins of the projectile or target are affected on the nuclear level density of the compound nucleus. The experimental data was analyzed by means of the couple channel spin effect formalism. This formalism suggests that the projectile spin is more effective on angular anisotropies within the limits of energy near the fusion barrier.

  19. Children's understanding of the Earth in a multicultural community: Mental models or fragments of knowledge?

    Science.gov (United States)

    Nobes, G.; Moore, D. G.; Martin, A. E.; Clifford, B. R.; Butterworth, G.; Panagiotaki, G.; Siegal, M.

    Asian and white British students ages 4-8 (N=167) were asked to select an earth from a set of plastic models and then respond to forced-choice questions. There were no significant differences in performance after accounting for language differences. Evidence suggests that children hold fragmentary knowledge rather than mental models, as suggested by previous researchers.

  20. SPECIAL LIBRARIES OF FRAGMENTS OF ALGORITHMIC NETWORKS TO AUTOMATE THE DEVELOPMENT OF ALGORITHMIC MODELS

    Directory of Open Access Journals (Sweden)

    V. E. Marley

    2015-01-01

    Full Text Available Summary. The concept of algorithmic models appeared from the algorithmic approach in which the simulated object, the phenomenon appears in the form of process, subject to strict rules of the algorithm, which placed the process of operation of the facility. Under the algorithmic model is the formalized description of the scenario subject specialist for the simulated process, the structure of which is comparable with the structure of the causal and temporal relationships between events of the process being modeled, together with all information necessary for its software implementation. To represent the structure of algorithmic models used algorithmic network. Normally, they were defined as loaded finite directed graph, the vertices which are mapped to operators and arcs are variables, bound by operators. The language of algorithmic networks has great features, the algorithms that it can display indifference the class of all random algorithms. In existing systems, automation modeling based on algorithmic nets, mainly used by operators working with real numbers. Although this reduces their ability, but enough for modeling a wide class of problems related to economy, environment, transport, technical processes. The task of modeling the execution of schedules and network diagrams is relevant and useful. There are many counting systems, network graphs, however, the monitoring process based analysis of gaps and terms of graphs, no analysis of prediction execution schedule or schedules. The library is designed to build similar predictive models. Specifying source data to obtain a set of projections from which to choose one and take it for a new plan.

  1. A Nuclear Waste Management Cost Model for Policy Analysis

    Science.gov (United States)

    Barron, R. W.; Hill, M. C.

    2017-12-01

    Although integrated assessments of climate change policy have frequently identified nuclear energy as a promising alternative to fossil fuels, these studies have often treated nuclear waste disposal very simply. Simple assumptions about nuclear waste are problematic because they may not be adequate to capture relevant costs and uncertainties, which could result in suboptimal policy choices. Modeling nuclear waste management costs is a cross-disciplinary, multi-scale problem that involves economic, geologic and environmental processes that operate at vastly different temporal scales. Similarly, the climate-related costs and benefits of nuclear energy are dependent on environmental sensitivity to CO2 emissions and radiation, nuclear energy's ability to offset carbon emissions, and the risk of nuclear accidents, factors which are all deeply uncertain. Alternative value systems further complicate the problem by suggesting different approaches to valuing intergenerational impacts. Effective policy assessment of nuclear energy requires an integrated approach to modeling nuclear waste management that (1) bridges disciplinary and temporal gaps, (2) supports an iterative, adaptive process that responds to evolving understandings of uncertainties, and (3) supports a broad range of value systems. This work develops the Nuclear Waste Management Cost Model (NWMCM). NWMCM provides a flexible framework for evaluating the cost of nuclear waste management across a range of technology pathways and value systems. We illustrate how NWMCM can support policy analysis by estimating how different nuclear waste disposal scenarios developed using the NWMCM framework affect the results of a recent integrated assessment study of alternative energy futures and their effects on the cost of achieving carbon abatement targets. Results suggest that the optimism reflected in previous works is fragile: Plausible nuclear waste management costs and discount rates appropriate for intergenerational cost

  2. MODELLING OF NUCLEAR POWER PLANT DECOMMISSIONING FINANCING

    Czech Academy of Sciences Publication Activity Database

    Bemš, J.; Knápek, J.; Králík, T.; Hejhal, M.; Kubančák, Ján; Vašíček, J.

    2015-01-01

    Roč. 164, č. 4 (2015), s. 519-522 ISSN 0144-8420 Institutional support: RVO:61389005 Keywords : nuclear power plant * methodology * future decommissioning costs Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.894, year: 2015

  3. Aggregated systems model for nuclear safeguards decisions

    International Nuclear Information System (INIS)

    1979-03-01

    This report summarizes a general analytical tool designed to assist nuclear safeguards decision-makers. The approach is based on decision analysis--a quantitative procedure for evaluating complex decision alternatives with uncertain outcomes. The report describes the general analytical approach in the context of safeguards decisions at a hypothetical nuclear fuel reprocessing plant

  4. Multi-solid and multi-fluid diffuse interface model: Applications to dynamic fracture and fragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Ndanou, S., E-mail: serge.ndanou@univ-amu.fr; Favrie, N., E-mail: nicolas.favrie@univ-amu.fr; Gavrilyuk, S., E-mail: sergey.gavrilyuk@univ-amu.fr

    2015-08-15

    We extend the model of diffuse solid–fluid interfaces developed earlier by authors of this paper to the case of arbitrary number of interacting hyperelastic solids. Plastic transformations of solids are taken into account through a Maxwell type model. The specific energy of each solid is given in separable form: it is the sum of a hydrodynamic part of the energy depending only on the density and the entropy, and an elastic part of the energy which is unaffected by the volume change. It allows us to naturally pass to the fluid description in the limit of vanishing shear modulus. In spite of a large number of governing equations, the model has a quite simple mathematical structure: it is a duplication of a single visco-elastic model. The model is well posed both mathematically and thermodynamically: it is hyperbolic and compatible with the second law of thermodynamics. The resulting model can be applied in the situations involving an arbitrary number of fluids and solids. In particular, we show the ability of the model to describe spallation and penetration phenomena occurring during high velocity impacts.

  5. Modelling of nuclear power plant decommissioning financing.

    Science.gov (United States)

    Bemš, J; Knápek, J; Králík, T; Hejhal, M; Kubančák, J; Vašíček, J

    2015-06-01

    Costs related to the decommissioning of nuclear power plants create a significant financial burden for nuclear power plant operators. This article discusses the various methodologies employed by selected European countries for financing of the liabilities related to the nuclear power plant decommissioning. The article also presents methodology of allocation of future decommissioning costs to the running costs of nuclear power plant in the form of fee imposed on each megawatt hour generated. The application of the methodology is presented in the form of a case study on a new nuclear power plant with installed capacity 1000 MW. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. The Use of Physics-Based Models to Predict Fragmentation of Ordnance

    National Research Council Canada - National Science Library

    Ott, Garland

    1997-01-01

    .... These same data collected from arena tests are also used as input for models used by other technical communities such as effectiveness, collateral damage, force protection, and weapon design. (1...

  7. Modeling fabrication of nuclear components: An integrative approach

    Energy Technology Data Exchange (ETDEWEB)

    Hench, K.W.

    1996-08-01

    Reduction of the nuclear weapons stockpile and the general downsizing of the nuclear weapons complex has presented challenges for Los Alamos. One is to design an optimized fabrication facility to manufacture nuclear weapon primary components in an environment of intense regulation and shrinking budgets. This dissertation presents an integrative two-stage approach to modeling the casting operation for fabrication of nuclear weapon primary components. The first stage optimizes personnel radiation exposure for the casting operation layout by modeling the operation as a facility layout problem formulated as a quadratic assignment problem. The solution procedure uses an evolutionary heuristic technique. The best solutions to the layout problem are used as input to the second stage - a simulation model that assesses the impact of competing layouts on operational performance. The focus of the simulation model is to determine the layout that minimizes personnel radiation exposures and nuclear material movement, and maximizes the utilization of capacity for finished units.

  8. A sample application of nuclear power human resources model

    International Nuclear Information System (INIS)

    Gurgen, A.; Ergun, S.

    2016-01-01

    One of the most important issues for a new comer country initializing the nuclear power plant projects is to have both quantitative and qualitative models for the human resources development. For the quantitative model of human resources development for Turkey, “Nuclear Power Human Resources (NPHR) Model” developed by the Los Alamos National Laboratory was used to determine the number of people that will be required from different professional or occupational fields in the planning of human resources for Akkuyu, Sinop and the third nuclear power plant projects. The number of people required for different professions for the Nuclear Energy Project Implementation Department, the regulatory authority, project companies, construction, nuclear power plants and the academy were calculated. In this study, a sample application of the human resources model is presented. The results of the first tries to calculate the human resources needs of Turkey were obtained. Keywords: Human Resources Development, New Comer Country, NPHR Model

  9. Framing Fragmentation

    DEFF Research Database (Denmark)

    Bundgaard, Charlotte

    2009-01-01

    Contemporary industrialized architecture based on advanced information technology and highly technological production processes, implies a radically different approach to architecture than what we have experienced in the past. Works of architecture composed of prefabricated building components......, contain distinctive architectural traits, not only based on rational repetition, but also supporting composition and montage as dynamic concepts. Prefab architecture is an architecture of fragmentation, individualization and changeability, and this sets up new challenges for the architect. This paper...... tries to develop a strategy for the architect dealing with industrially based architecture; a strategy which exploits architectural potentials in industrial building, which recognizes the rules of mass production and which redefines the architect’s position among the agents of building. If recent...

  10. Sedimentary modelling and nuclear-waste disposal

    International Nuclear Information System (INIS)

    Van Loon, A.J.

    1982-01-01

    Nuclear energy is an important source of energy. Recently a slow down is experienced in its growth rate, due to the following factors: a) the supposed shortage of uranium; b) the fear for the consequences of nuclear accident, and c) the problem of nuclear wastes. Two types of waste are distinguished: a) fission products and actinides, and b) operational waste. The United States have started a program that must lead in 1989 to the first final storage of such waste in salt. Open-pit mines and oil-well drilling are discussed as possible solutions for operational waste storage

  11. The Nuclear Shell Model and its Relation with Other Nuclear Models

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, J. P. [University of Sussex, Brighton (United Kingdom)

    1963-01-15

    The starting point of all versions of the shell model is the physical idea that the interaction between a given nucleon and all the others resembles that between a nucleon and a fixed field. From this starting point one might attempt to construct a field which is self-consistent but this approach is not followed in most shell-model calculations because of the complications that arise. The more usual approach has been to use the idea of an average field to provide a complete set of sin gle-particle wave functions. Then, if the parameters of the field (e.g. its size) are correctly chosen, we would expect to reach a good approximation to the nuclear-wave function by taking that configuration of single-particle wave functions which has lowest energy in this field. The wave functions could clearly be improved by allowing the mixing of excited configurations but this is rarely done because of the resulting complexity of the problem. Even in the lowest configuration there are in general many independent wave functions for a many-particle system which would all be degenerate in the average field. To find the nuclear energy levels and wave functions we must therefore build up the energy matrix in this degenerate set, using the inter-nucleon two-body forces, and then diagonalize this matrix. If the detailed form of the nuclear forces was known we might regard such calculations as the first step towards an exact calculation in which higher configurations were included but every indication is that the convergence would be extremely slow. It is more usual to treat an energy calculation in the lowest configuration unashamedly as a model calculation and to attempt to deduce, by comparisons with experimental data in the many-particle nuclei, the nature of the effective nuclear forces required in that configuration. If the model is realistic then we should not expect these effective forces to change very much in going from one nucleus to its neighbour and since there are many more

  12. Quantum statistical model of nuclear multifragmentation in the canonical ensemble method

    International Nuclear Information System (INIS)

    Toneev, V.D.; Ploszajczak, M.; Parvant, A.S.; Toneev, V.D.; Parvant, A.S.

    1999-01-01

    A quantum statistical model of nuclear multifragmentation is proposed. The recurrence equation method used the canonical ensemble makes the model solvable and transparent to physical assumptions and allows to get results without involving the Monte Carlo technique. The model exhibits the first order phase transition. Quantum statistics effects are clearly seen on the microscopic level of occupation numbers but are almost washed out for global thermodynamic variables and the averaged observables studied. In the latter case, the recurrence relations for multiplicity distributions of both intermediate-mass and all fragments are derived and the specific changes in the shape of multiplicity distributions in the narrow region of the transition temperature is stressed. The temperature domain favorable to search for the HBT effect is noted. (authors)

  13. Quantum statistical model of nuclear multifragmentation in the canonical ensemble method

    Energy Technology Data Exchange (ETDEWEB)

    Toneev, V.D.; Ploszajczak, M. [Grand Accelerateur National d' Ions Lourds (GANIL), 14 - Caen (France); Parvant, A.S. [Institute of Applied Physics, Moldova Academy of Sciences, MD Moldova (Ukraine); Parvant, A.S. [Joint Institute for Nuclear Research, Bogoliubov Lab. of Theoretical Physics, Dubna (Russian Federation)

    1999-07-01

    A quantum statistical model of nuclear multifragmentation is proposed. The recurrence equation method used the canonical ensemble makes the model solvable and transparent to physical assumptions and allows to get results without involving the Monte Carlo technique. The model exhibits the first order phase transition. Quantum statistics effects are clearly seen on the microscopic level of occupation numbers but are almost washed out for global thermodynamic variables and the averaged observables studied. In the latter case, the recurrence relations for multiplicity distributions of both intermediate-mass and all fragments are derived and the specific changes in the shape of multiplicity distributions in the narrow region of the transition temperature is stressed. The temperature domain favorable to search for the HBT effect is noted. (authors)

  14. Modelling loading and break-up of RC structure due to internal explosion of fragmenting shells

    NARCIS (Netherlands)

    Weerheijm, J.; Stolz, A.; Riedel, W.; Mediavilla Varas, J.

    2012-01-01

    The Klotz Group (KG), an international group of experts on explosion safety, investigates the debris throw hazard associated with the accidental detonation of ammunition in reinforced concrete (RC-) structures. Experiments are combined with engineering models but also with results of advanced

  15. Modelling loading and break-up of RC structure due to internal explosion of fragmenting shells

    NARCIS (Netherlands)

    Weerheijm, J.; Stolz, A.; Riedel, W.; Mediavilla, J.

    2012-01-01

    The Klotz Group (KG), an mtemational group of experts on explosion safety, investigates the debris throw hazard associated with the accidental detonation of ammunition in reinforced concrete (RC-) structures. Experiments are combined with engineering models but also with results of advanced

  16. Validation of Geant4 fragmentation for Heavy Ion Therapy

    Science.gov (United States)

    Bolst, David; Cirrone, Giuseppe A. P.; Cuttone, Giacomo; Folger, Gunter; Incerti, Sebastien; Ivanchenko, Vladimir; Koi, Tatsumi; Mancusi, Davide; Pandola, Luciano; Romano, Francesco; Rosenfeld, Anatoly B.; Guatelli, Susanna

    2017-10-01

    12C ion therapy has had growing interest in recent years for its excellent dose conformity. However at therapeutic energies, which can be as high as 400 MeV/u, carbon ions produce secondary fragments. For an incident 400 MeV/u 12C ion beam, ∼ 70 % of the beam will undergo fragmentation before the Bragg Peak. The dosimetric and radiobiological impact of these fragments must be accurately characterised, as it can result in increasing the risk of secondary cancer for the patient as well as altering the relative biological effectiveness. This work investigates the accuracy of three different nuclear fragmentation models available in the Monte Carlo Toolkit Geant4, the Binary Intranuclear Cascade (BIC), the Quantum Molecular Dynamics (QMD) and the Liege Intranuclear Cascade (INCL++). The models were benchmarked against experimental data for a pristine 400 MeV/u 12C beam incident upon a water phantom, including fragment yield, angular and energy distribution. For fragment yields the three alternative models agreed between ∼ 5 and ∼ 35 % with experimental measurements, the QMD using the "Frag" option gave the best agreement for lighter fragments but had reduced agreement for larger fragments. For angular distributions INCL++ was seen to provide the best agreement among the models for all elements with the exception of Hydrogen, while BIC and QMD was seen to produce broader distributions compared to experiment. BIC and QMD performed similar to one another for kinetic energy distributions while INCL++ suffered from producing lower energy distributions compared to the other models and experiment.

  17. A putative non-hr origin of DNA replication in the HindIII-K fragment of Autographa californica multiple nucleocapsid nuclear polyhedrosis virus

    NARCIS (Netherlands)

    Kool, M.; Goldbach, R. W.; Vlak, J. M.

    1994-01-01

    In addition to the seven known homologous regions (hrs) of Autographa californica multiple nucleocapsid polyhedrosis virus (AcMNPV) the HindIII-K fragment was also found to carry a putative ori, although this fragment does not contain an hr. Deletion analysis showed that this ori contains several

  18. Development of Dynamic Spent Nuclear Fuel Environmental Effect Analysis Model

    International Nuclear Information System (INIS)

    Jeong, Chang Joon; Ko, Won Il; Lee, Ho Hee; Cho, Dong Keun; Park, Chang Je

    2010-07-01

    The dynamic environmental effect evaluation model for spent nuclear fuel has been developed and incorporated into the system dynamic DANESS code. First, the spent nuclear fuel isotope decay model was modeled. Then, the environmental effects were modeled through short-term decay heat model, short-term radioactivity model, and long-term heat load model. By using the developed model, the Korean once-through nuclear fuel cycles was analyzed. The once-through fuel cycle analysis was modeled based on the Korean 'National Energy Basic Plan' up to 2030 and a postulated nuclear demand growth rate until 2150. From the once-through results, it is shown that the nuclear power demand would be ∼70 GWe and the total amount of the spent fuel accumulated by 2150 would be ∼168000 t. If the disposal starts from 2060, the short-term decay heat of Cs-137 and Sr-90 isotopes are W and 1.8x10 6 W in 2100. Also, the total long-term heat load in 2100 will be 4415 MW-y. From the calculation results, it was found that the developed model is very convenient and simple for evaluation of the environmental effect of the spent nuclear fuel

  19. Multi-Scale Particle Size Distributions of Mars, Moon and Itokawa based on a time-maturation dependent fragmentation model

    Science.gov (United States)

    Charalambous, C. A.; Pike, W. T.

    2013-12-01

    We present the development of a soil evolution framework and multiscale modelling of the surface of Mars, Moon and Itokawa thus providing an atlas of extra-terrestrial Particle Size Distributions (PSD). These PSDs are profoundly based on a tailoring method which interconnects several datasets from different sites captured by the various missions. The final integrated product is then fully justified through a soil evolution analysis model mathematically constructed via fundamental physical principles (Charalambous, 2013). The construction of the PSD takes into account the macroscale fresh primary impacts and their products, the mesoscale distributions obtained by the in-situ data of surface missions (Golombek et al., 1997, 2012) and finally the microscopic scale distributions provided by Curiosity and Phoenix Lander (Pike, 2011). The distribution naturally extends at the magnitudinal scales at which current data does not exist due to the lack of scientific instruments capturing the populations at these data absent scales. The extension is based on the model distribution (Charalambous, 2013) which takes as parameters known values of material specific probabilities of fragmentation and grinding limits. Additionally, the establishment of a closed-form statistical distribution provides a quantitative description of the soil's structure. Consequently, reverse engineering of the model distribution allows the synthesis of soil that faithfully represents the particle population at the studied sites (Charalambous, 2011). Such representation essentially delivers a virtual soil environment to work with for numerous applications. A specific application demonstrated here will be the information that can directly be extracted for the successful drilling probability as a function of distance in an effort to aid the HP3 instrument of the 2016 Insight Mission to Mars. Pike, W. T., et al. "Quantification of the dry history of the Martian soil inferred from in situ microscopy

  20. Achieving high baryon densities in the fragmentation regions in heavy ion collisions at top RHIC energy

    International Nuclear Information System (INIS)

    Li, Ming; Kapusta, Joseph I.

    2017-01-01

    Heavy ion collisions at extremely high energy, such as the top energy at RHIC, exhibit the property of transparency where there is a clear separation between the almost net-baryon-free central rapidity region and the net-baryon-rich fragmentation region. We calculate the net-baryon rapidity loss and the nuclear excitation energy using the energy-momentum tensor obtained from the McLerran-Venugopalan model. Nuclear compression during the collision is further estimated using a simple space-time picture. The results show that extremely high baryon densities, about twenty times larger than the normal nuclear density, can be achieved in the fragmentation regions. (paper)

  1. Evaluating realized seed dispersal across fragmented tropical landscapes : a two-fold approach using parentage analysis and the neighbourhood model

    NARCIS (Netherlands)

    Ismail, Sascha A.; Ghazoul, Jaboury; Ravikanth, Gudasalamani; Kushalappa, Cheppudira G.; Uma Shaanker, Ramanan; Kettle, Chris J.

    2017-01-01

    Despite the importance of seed dispersal for survival of plant species in fragmented landscapes, data on seed dispersal at landscape scales remain sparse. Effective seed dispersal among fragments determines recolonization and plant species persistence in such landscapes. We present the first

  2. Contribution to numerical and mechanical modelling of pellet-cladding interaction in nuclear reactor fuel rod

    International Nuclear Information System (INIS)

    Retel, V.

    2002-12-01

    Pressurised water reactor fuel rods (PWR) are the place of nuclear fission, resulting in unstable and radioactive elements. Today, the mechanical loading on the cladding is harder and harder and is partly due to the fuel pellet movement. Then, the mechanical behaviour of the cladding needs to be simulated with models allowing to assess realistic stress and strain fields for all the running conditions. Besides, the mechanical treatment of the fuel pellet needs to be improved. The study is part of a global way of improving the treatment of pellet-cladding interaction (PCI) in the 1D finite elements EDF code named CYRANO3. Non-axisymmetrical multidirectional effects have to be accounted for in a context of unidirectional axisymmetrical finite elements. The aim of this work is double. Firstly a model simulating the effect of stress concentration on the cladding, due to the opening of the radial cracks of fuel, had been added in the code. Then, the fragmented state of fuel material has been taken into account in the thermomechanical calculation, through a model which led the strain and stress relaxation in the pellet due to the fragmentation, be simulated. This model has been implemented in the code for two types of fuel behaviour: elastic and viscoplastic. (author)

  3. Nuclear spin noise in the central spin model

    Science.gov (United States)

    Fröhling, Nina; Anders, Frithjof B.; Glazov, Mikhail

    2018-05-01

    We study theoretically the fluctuations of the nuclear spins in quantum dots employing the central spin model which accounts for the hyperfine interaction of the nuclei with the electron spin. These fluctuations are calculated both with an analytical approach using homogeneous hyperfine couplings (box model) and with a numerical simulation using a distribution of hyperfine coupling constants. The approaches are in good agreement. The box model serves as a benchmark with low computational cost that explains the basic features of the nuclear spin noise well. We also demonstrate that the nuclear spin noise spectra comprise a two-peak structure centered at the nuclear Zeeman frequency in high magnetic fields with the shape of the spectrum controlled by the distribution of the hyperfine constants. This allows for direct access to this distribution function through nuclear spin noise spectroscopy.

  4. Fragmentation of atomic clusters: A theoretical study

    International Nuclear Information System (INIS)

    Lopez, M.J.; Jellinek, J.

    1994-01-01

    Collisionless fragmentation of nonrotating model n-atom metal clusters (n=12, 13, and 14) is studied using isoergic molecular-dynamics simulations. Minimum-energy paths for fragmentation are mapped out as functions of the distance between the centers of mass of the fragments. These paths provide information on the fragmentation energies for the different fragmentation channels. Fragmentation patterns (distributions of the fragmentation channel probabilities) and global and channel-specific fragmentation rate constants are computed and analyzed as functions of the internal energy and of the size of the clusters. The trends derived from the dynamics are compared with those obtained using the RRK and TST statistical approaches. The dynamics of the fragmentation process is analyzed in terms of characteristic quantities such as the distance between the centers of mass of the fragments, their relative translational energy, and their interaction energy, all considered as functions of time

  5. The glass model of Muelheim-Kaerlich nuclear power station

    International Nuclear Information System (INIS)

    Kuttruf, H.; Lemke, W.

    1986-01-01

    The glass model represents the nuclear steam generator system of Muelheim-Kaerlich nuclear power station on a scale of 1:25 and in simplified form, so that the thermohydraulic behaviour in both normal operational and fault conditions can be represented. A set-up time of about one hour results in a helpful aid to instruction. (orig.) [de

  6. Chaotic behaviour of the nuclear shell-model hamiltonian

    International Nuclear Information System (INIS)

    Dias, H.; Hussein, M.S.; Oliveira, N.A. de; Wildenthal, B.H.

    1987-11-01

    Large scale nuclear shell-model calculations for several nuclear systems are discussed. In particular, the statistical baheviour of the energy eigenvalues and eigenstates, are discussed. The chaotic behaviour of the NSMH is then shown to be quite useful in calculating the spreading width of the highly collective multipole giant resonances. (author) [pt

  7. Nuclear model codes available at the Nuclear Energy Agency Computer Program Library (NEA-CPL)

    International Nuclear Information System (INIS)

    Sartori, E.; Garcia Viedma, L. de

    1976-01-01

    This paper briefly outlines the objectives of the NEA-CPL and its activities in the field of Nuclear Model Computer Codes. A short description of the computer codes available from the CPL in this field is also presented. (author)

  8. Building better optical model potentials for nuclear astrophysics applications

    International Nuclear Information System (INIS)

    Bauge, Eric; Dupuis, Marc

    2004-01-01

    In nuclear astrophysics, optical model potentials play an important role, both in the nucleosynthesis models, and in the interpretation of astrophysics related nuclear physics measurements. The challenge of nuclear astrophysics resides in the fact that it involves many nuclei far from the stability line, implying than very few (if any) experimental results are available for these nuclei. The answer to this challenge is a heavy reliance on microscopic optical models with solid microscopic physics foundations that can predict the relevant physical quantities with good accuracy. This use of microscopic information limits the likelihood of the model failing spectacularly (except if some essential physics was omitted in the modeling) when extrapolating away from the stability line, in opposition to phenomenological models which are only suited for interpolation between measured data points and not for extrapolating towards unexplored areas of the chart of the nuclides.We will show how these microscopic optical models are built, how they link to our present knowledge of nuclear structure, and how they affect predictions of nuclear astrophysics models and the interpretation of some key nuclear physics measurements for astrophysics

  9. Covariance matrices for nuclear cross sections derived from nuclear model calculations

    International Nuclear Information System (INIS)

    Smith, D. L.

    2005-01-01

    The growing need for covariance information to accompany the evaluated cross section data libraries utilized in contemporary nuclear applications is spurring the development of new methods to provide this information. Many of the current general purpose libraries of evaluated nuclear data used in applications are derived either almost entirely from nuclear model calculations or from nuclear model calculations benchmarked by available experimental data. Consequently, a consistent method for generating covariance information under these circumstances is required. This report discusses a new approach to producing covariance matrices for cross sections calculated using nuclear models. The present method involves establishing uncertainty information for the underlying parameters of nuclear models used in the calculations and then propagating these uncertainties through to the derived cross sections and related nuclear quantities by means of a Monte Carlo technique rather than the more conventional matrix error propagation approach used in some alternative methods. The formalism to be used in such analyses is discussed in this report along with various issues and caveats that need to be considered in order to proceed with a practical implementation of the methodology

  10. Excited nuclei fragmentation

    International Nuclear Information System (INIS)

    Ngo, C.

    1986-11-01

    Experimental indications leading to the thought of a very excited nucleus fragmentation are resumed. Theoretical approaches are briefly described; they are used to explain the phenomenon in showing off they are based on a minimum information principle. This model is based on time dependent Thomas-Fermi calculation which allows the mean field effect description, and with a site-bound percolation model which allows the fluctuation description [fr

  11. Far from the intermediate nuclear field

    International Nuclear Information System (INIS)

    Dietrich, K.; Wagner, G.J.; Gregoire, C.; Campi, X.; Silvestre-Brac, B.; Platchkov, S.; Mayer, B.; Abgrall, Y.; Bohigas, O.; Grange, P.; Signarbieux, C.

    1988-01-01

    Pairing correlations in nuclear physics; the BCS state and quasi-particles; the layer model; collision effects on nuclear dynamics; the theory of cluster formation (application to nucleus fragmentation); short range correlations (few-particle systems); deuterium electron scattering; dibaryonic resonances; traditional and exotic hadron probes of nuclear structure; spectral fluctuations and chaotic motion; corrections to the intermediate nuclear field (nonrelativistic and other effects); and heavy nuclei splitting and nuclear superfluidity are introduced [fr

  12. Nuclear Hybrid Energy Systems FY16 Modeling Efforts at ORNL

    Energy Technology Data Exchange (ETDEWEB)

    Cetiner, Sacit M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Greenwood, Michael Scott [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Harrison, Thomas J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Qualls, A. L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Guler Yigitoglu, Askin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Fugate, David W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-01

    A nuclear hybrid system uses a nuclear reactor as the basic power generation unit. The power generated by the nuclear reactor is utilized by one or more power customers as either thermal power, electrical power, or both. In general, a nuclear hybrid system will couple the nuclear reactor to at least one thermal power user in addition to the power conversion system. The definition and architecture of a particular nuclear hybrid system is flexible depending on local markets needs and opportunities. For example, locations in need of potable water may be best served by coupling a desalination plant to the nuclear system. Similarly, an area near oil refineries may have a need for emission-free hydrogen production. A nuclear hybrid system expands the nuclear power plant from its more familiar central power station role by diversifying its immediately and directly connected customer base. The definition, design, analysis, and optimization work currently performed with respect to the nuclear hybrid systems represents the work of three national laboratories. Idaho National Laboratory (INL) is the lead lab working with Argonne National Laboratory (ANL) and Oak Ridge National Laboratory. Each laboratory is providing modeling and simulation expertise for the integration of the hybrid system.

  13. Intermittency in nuclear multifragmentation

    International Nuclear Information System (INIS)

    Ploszajczak, M.; Tucholski, A.

    1990-07-01

    Fluctuations of the fragment size distribution in a percolation model and in nuclear multifragmentation following the breakup of high energy nuclei in the nuclear emulsion are studied using the method of scaled factorial moments. An intermittent patern of fluctuations is found in the data as well as in the percolation lattice calculation. This is a consequence of both a self-similarity in the fragment size distribution and a random character for the scaling law. These fluctuations are in general well-described by percolation model. The multifractal dimensions are calculated and their relevance to the study of possible critical behaviour is pointed out. (orig.)

  14. A Monte Carlo Approach to Modeling the Breakup of the Space Launch System EM-1 Core Stage with an Integrated Blast and Fragment Catalogue

    Science.gov (United States)

    Richardson, Erin; Hays, M. J.; Blackwood, J. M.; Skinner, T.

    2014-01-01

    The Liquid Propellant Fragment Overpressure Acceleration Model (L-FOAM) is a tool developed by Bangham Engineering Incorporated (BEi) that produces a representative debris cloud from an exploding liquid-propellant launch vehicle. Here it is applied to the Core Stage (CS) of the National Aeronautics and Space Administration (NASA) Space Launch System (SLS launch vehicle). A combination of Probability Density Functions (PDF) based on empirical data from rocket accidents and applicable tests, as well as SLS specific geometry are combined in a MATLAB script to create unique fragment catalogues each time L-FOAM is run-tailored for a Monte Carlo approach for risk analysis. By accelerating the debris catalogue with the BEi blast model for liquid hydrogen / liquid oxygen explosions, the result is a fully integrated code that models the destruction of the CS at a given point in its trajectory and generates hundreds of individual fragment catalogues with initial imparted velocities. The BEi blast model provides the blast size (radius) and strength (overpressure) as probabilities based on empirical data and anchored with analytical work. The coupling of the L-FOAM catalogue with the BEi blast model is validated with a simulation of the Project PYRO S-IV destruct test. When running a Monte Carlo simulation, L-FOAM can accelerate all catalogues with the same blast (mean blast, 2 s blast, etc.), or vary the blast size and strength based on their respective probabilities. L-FOAM then propagates these fragments until impact with the earth. Results from L-FOAM include a description of each fragment (dimensions, weight, ballistic coefficient, type and initial location on the rocket), imparted velocity from the blast, and impact data depending on user desired application. LFOAM application is for both near-field (fragment impact to escaping crew capsule) and far-field (fragment ground impact footprint) safety considerations. The user is thus able to use statistics from a Monte Carlo

  15. Concurrent algorithms for nuclear shell model calculations

    International Nuclear Information System (INIS)

    Mackenzie, L.M.; Macleod, A.M.; Berry, D.J.; Whitehead, R.R.

    1988-01-01

    The calculation of nuclear properties has proved very successful for light nuclei, but is limited by the power of the present generation of computers. Starting with an analysis of current techniques, this paper discusses how these can be modified to map parallelism inherent in the mathematics onto appropriate parallel machines. A prototype dedicated multiprocessor for nuclear structure calculations, designed and constructed by the authors, is described and evaluated. The approach adopted is discussed in the context of a number of generically similar algorithms. (orig.)

  16. Light-front nuclear shell-model

    International Nuclear Information System (INIS)

    Johnson, M.B.

    1990-01-01

    I examine the effects of nuclear structure on high-energy, high-momentum transfer processes, specifically the EMC effect. For pedagogical reasons, a fictitious but simple two-body system consisting of two equal-mass particles interacting in a harmonic oscillator potential has been chosen. For this toy nucleus, I utilize a widely-used link between instant-form and light-front dynamics, formulating nuclear structure and deep-inelastic scattering consistently in the laboratory system. Binding effects are compared within conventional instant-form and light-front dynamical frameworks, with appreciable differences being found in the two cases. 20 refs

  17. Power systems with nuclear-electric generators - Modelling methods

    International Nuclear Information System (INIS)

    Valeca, Serban Constantin

    2002-01-01

    This is a vast analysis on the issue of sustainable nuclear power development with direct conclusions regarding the Nuclear Programme of Romania. The work is targeting specialists and decision making boards. Specific to the nuclear power development is its public implication, the public being most often misinformed by non-professional media. The following problems are debated thoroughly: - safety, nuclear risk, respectively, is treated in chapter 1 and 7 aiming at highlighting the quality of nuclear power and consequently paving the way to public acceptance; - the environment considered both as resource of raw materials and medium essential for life continuation, which should be appropriately protected to ensure healthy and sustainable development of human society; its analysis is also presented in chapter 1 and 7, where the problem of safe management of radioactive waste is addressed too; - investigation methods based on information science of nuclear systems, applied in carrying out the nuclear strategy and planning are widely analyzed in the chapter 2, 3 and 6; - optimizing the processes by following up the structure of investment and operation costs, and, generally, the management of nuclear units is treated in the chapter 5 and 7; - nuclear weapon proliferation as a possible consequence of nuclear power generation is treated as a legal issue. The development of Romanian NPP at Cernavoda, practically, the core of the National Nuclear Programme, is described in chapter 8. Actually, the originality of the present work consists in the selection and adaptation from a multitude of mathematical models applicable to the local and specific conditions of nuclear power plant at Cernavoda. The Romanian economy development and power development oriented towards reduction of fossil fuel consumption and protection of environment, most reliably ensured by the nuclear power, is discussed in the frame of the world trends of the energy production. Various scenarios are

  18. Equations of the quasiparticle-phonon nuclear model with effective finite-rank separable interactions

    International Nuclear Information System (INIS)

    Solov'ev, V.G.

    1989-01-01

    Basic equations are derived for the quasiparticle-phonon nuclear model for the finite-rank separable isoscalar and isovector multipole and spin-multipole and isovector tensor particle-hole and particle-particle interactions between quasiparticles. For even-even spherical nuclei it is shown that in the calculation of single-phonon states in the random phase approximation a significant complication arises due to the finite rank n max >1 of separable interactions. Taking into account separable interactions with n max >1 does not lead to significant difficulties in the calculation of fragmentation of quasiparticle and collective states. It is asserted that the model can be used as a basis for calculations of many characteristics of complex nuclei

  19. Operational characteristics of nuclear power plants - modelling of operational safety

    International Nuclear Information System (INIS)

    Studovic, M.

    1984-01-01

    By operational experience of nuclear power plants and realize dlevel of availability of plant, systems and componenst reliabiliuty, operational safety and public protection, as a source on nature of distrurbances in power plant systems and lessons drawn by the TMI-2, in th epaper are discussed: examination of design safety for ultimate ensuring of safe operational conditions of the nuclear power plant; significance of the adequate action for keeping proess parameters in prescribed limits and reactor cooling rquirements; developed systems for measurements detection and monitoring all critical parameters in the nuclear steam supply system; contents of theoretical investigation and mathematical modeling of the physical phenomena and process in nuclear power plant system and components as software, supporting for ensuring of operational safety and new access in staff education process; program and progress of the investigation of some physical phenomena and mathematical modeling of nuclear plant transients, prepared at faculty of mechanical Engineering in Belgrade. (author)

  20. Seismic model of the nuclear boiler SPX2

    International Nuclear Information System (INIS)

    Christodoulou, K.

    1982-01-01

    A model of the nuclear boiler SPX2 is proposed in this paper enabling to carry out comparative calculations on the response to seismic effects. The calculations are made in CISE and SEPTEN departments of Electricite de France [fr

  1. The U(3) principle as base of a microscopical U(3) model for the clarification of the phenomenon of nuclear molecules

    International Nuclear Information System (INIS)

    Bader, R.

    1985-01-01

    The tenor of this thesis is the regarding of the U(3) symmetry in the study of nuclear reactions. By the description of the two colliding fragments and their relative motion by means of U(3) quantum numbers U(3) channels and U(3) channel sets are defined. It is shown that in certain collisions the U(3) symmetry of U(3) channels is incompatible with the U(3) symmetry of the compound nucleus. For these U(3) channels the formation of the compound nucleus is forbidden. In this framework a microscopical U(3) model for the phenomenon of the nuclear molecule resonances is developed. U(3) barriers which play an important role in this model are responsible for the repulsion between the two fragments. By microscopical calculations it is confirmed that by the U(3) channels allowed above the U(3) barriers an attraction between the two fragments arises. This interchange of attraction and repulsion leads to the formation of nuclear molecules. Furthermore it is shown that this incompatibility and by this the phenomenon of nuclear molecule resonances can be reduced to an U(3) principle in which the Pauli principle is contained. Basing on this U(3) principle selection rules are formulated which predict candidates for nuclear molecule resonances. This explains why only some binary systems tend to the molecule formation. (orig./HSI) [de

  2. Photon-hadron fragmentation: theoretical situation

    International Nuclear Information System (INIS)

    Peschanski, R.

    1983-07-01

    Using a selection of new experimental results models of hadronic fragmentation and their phenomenological comparison are presented. Indeed a convenient theory of hadronic fragmentation -for instance based on Q.C.D.- does not exist: low transverse momentum fragmentation involves the badly known hadronic long-range forces. Models should clarify the situation in the prospect of an eventual future theory

  3. Sustainable multilateral nuclear fuel cycle framework. (2) Models for multilateral nuclear fuel cycle approach

    International Nuclear Information System (INIS)

    Adachi, T; Tanaka, S; Tazaki, M; Akiba, M; Takashima, R; Kuno, Y

    2011-01-01

    To construct suitable models for a reliable and sustainable international/regional framework in the fields of nuclear fuel cycle, it is essential to reflect recent political situations including such that 1) a certain number of emerging countries especially in south-east Asia want to introduce and develop nuclear power in the long-terms despite the accident of the Fukushima Daiichi NPP, and 2) exposition of nuclear proliferation threats provided by North Korea and Iran. It is also to be considered that Japan is an unique country having enrichment and reprocessing facilities on commercial base among non-nuclear weapon countries. Although many models presented for the internationalization have not been realized yet, studies at the University of Tokyo aim at multilateral nuclear approach (MNA) in Asian-Pacific countries balancing between nuclear non-proliferation and nuclear fuel supply/service and presenting specific examples such as prerequisites for participating countries, scope of cooperative activities, ownership of facilities and type of agreements/frameworks. We will present a model basic agreement and several bilateral and multi-lateral agreements for the combinations of industry or government led consortia including Japan and its neighboring countries and made a preliminary evaluation for the combination of processes/facilities based on the INFCIRC/640 report for MNA. (author)

  4. Tumor penetration with intact MAb and fragments demonstrated in vitro on tumor spheroids and in vivo in the nude mouse model

    International Nuclear Information System (INIS)

    Buchegger, F.; Halpern, S.E.; Sutherland, R.M.; Schreyer, M.; Mach, J.P.

    1986-01-01

    Tumor spheroids grown in culture represent a good in vitro model for the study of tumor penetration phenomena of potential radiotherapeutics. Using this system, it was found that Fab-fragments penetrate tumors more quickly and deeply than complete antibodies. These results were confirmed in tumor bearing nephrectomized nude mice

  5. Analytical solution of dispersion relations for the nuclear optical model

    Energy Technology Data Exchange (ETDEWEB)

    VanderKam, J.M. [Center for Communications Research, Thanet Road, Princeton, NJ 08540 (United States); Weisel, G.J. [Triangle Universities Nuclear Laboratory, and Duke University, Box 90308, Durham, NC 27708-0308 (United States); Penn State Altoona, 3000 Ivyside Park, Altoona, PA 16601-3760 (United States); Tornow, W. [Triangle Universities Nuclear Laboratory, and Duke University, Box 90308, Durham, NC 27708-0308 (United States)

    2000-12-01

    Analytical solutions of dispersion integral relations, linking the real and imaginary parts of the nuclear optical model, have been derived. These are displayed for some widely used forms of the volume- and surface-absorptive nuclear potentials. When the analytical solutions are incorporated into the optical-model search code GENOA, replacing a numerical integration, the code runs three and a half to seven times faster, greatly aiding the analysis of direct-reaction, elastic scattering data. (author)

  6. Fire models for assessment of nuclear power plant fires

    International Nuclear Information System (INIS)

    Nicolette, V.F.; Nowlen, S.P.

    1989-01-01

    This paper reviews the state-of-the-art in available fire models for the assessment of nuclear power plants fires. The advantages and disadvantages of three basic types of fire models (zone, field, and control volume) and Sandia's experience with these models will be discussed. It is shown that the type of fire model selected to solve a particular problem should be based on the information that is required. Areas of concern which relate to all nuclear power plant fire models are identified. 17 refs., 6 figs

  7. Evaluating nuclear physics inputs in core-collapse supernova models

    Science.gov (United States)

    Lentz, E.; Hix, W. R.; Baird, M. L.; Messer, O. E. B.; Mezzacappa, A.

    Core-collapse supernova models depend on the details of the nuclear and weak interaction physics inputs just as they depend on the details of the macroscopic physics (transport, hydrodynamics, etc.), numerical methods, and progenitors. We present preliminary results from our ongoing comparison studies of nuclear and weak interaction physics inputs to core collapse supernova models using the spherically-symmetric, general relativistic, neutrino radiation hydrodynamics code Agile-Boltztran. We focus on comparisons of the effects of the nuclear EoS and the effects of improving the opacities, particularly neutrino--nucleon interactions.

  8. The study of hadronic matter at the highest density; the search for the deconfined quark-gluon phase using 2 TeV anti p-p collisions; and the exclusive study of nuclear fragmentation using the Lawrence Berkeley Laboratory EOS-TPC

    International Nuclear Information System (INIS)

    Scharenberg, R.P.; Hirsch, A.S.

    1990-01-01

    This report discusses the: Fermilab experiment 735, a search for the quark-gluon plasma; an exclusive study of nuclear fragmentation using the EOS-TPC; and a study of the central rapidity region at the relativistic heavy ion collider

  9. Solving the nuclear shell model with an algebraic method

    International Nuclear Information System (INIS)

    Feng, D.H.; Pan, X.W.; Guidry, M.

    1997-01-01

    We illustrate algebraic methods in the nuclear shell model through a concrete example, the fermion dynamical symmetry model (FDSM). We use this model to introduce important concepts such as dynamical symmetry, symmetry breaking, effective symmetry, and diagonalization within a higher-symmetry basis. (orig.)

  10. The string model of nuclear scattering: an introduction

    International Nuclear Information System (INIS)

    Werner, Klaus

    1995-01-01

    We discuss the string model of hadronic and nuclear scattering at ultrarelativistic energies. The man purpose is to treat theoretical concepts common to essentially all successful models: strings, Pomerons, and their marriage int he string model approach. We stay an introductory level without going into technical details. (author)

  11. Monte Carlo Numerical Models for Nuclear Logging Applications

    Directory of Open Access Journals (Sweden)

    Fusheng Li

    2012-06-01

    Full Text Available Nuclear logging is one of most important logging services provided by many oil service companies. The main parameters of interest are formation porosity, bulk density, and natural radiation. Other services are also provided from using complex nuclear logging tools, such as formation lithology/mineralogy, etc. Some parameters can be measured by using neutron logging tools and some can only be measured by using a gamma ray tool. To understand the response of nuclear logging tools, the neutron transport/diffusion theory and photon diffusion theory are needed. Unfortunately, for most cases there are no analytical answers if complex tool geometry is involved. For many years, Monte Carlo numerical models have been used by nuclear scientists in the well logging industry to address these challenges. The models have been widely employed in the optimization of nuclear logging tool design, and the development of interpretation methods for nuclear logs. They have also been used to predict the response of nuclear logging systems for forward simulation problems. In this case, the system parameters including geometry, materials and nuclear sources, etc., are pre-defined and the transportation and interactions of nuclear particles (such as neutrons, photons and/or electrons in the regions of interest are simulated according to detailed nuclear physics theory and their nuclear cross-section data (probability of interacting. Then the deposited energies of particles entering the detectors are recorded and tallied and the tool responses to such a scenario are generated. A general-purpose code named Monte Carlo N– Particle (MCNP has been the industry-standard for some time. In this paper, we briefly introduce the fundamental principles of Monte Carlo numerical modeling and review the physics of MCNP. Some of the latest developments of Monte Carlo Models are also reviewed. A variety of examples are presented to illustrate the uses of Monte Carlo numerical models

  12. Nuclear Hybrid Energy System Model Stability Testing

    Energy Technology Data Exchange (ETDEWEB)

    Greenwood, Michael Scott [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cetiner, Sacit M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Fugate, David W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-04-01

    A Nuclear Hybrid Energy System (NHES) uses a nuclear reactor as the basic power generation unit, and the power generated is used by multiple customers as combinations of thermal power or electrical power. The definition and architecture of a particular NHES can be adapted based on the needs and opportunities of different localities and markets. For example, locations in need of potable water may be best served by coupling a desalination plant to the NHES. Similarly, a location near oil refineries may have a need for emission-free hydrogen production. Using the flexible, multi-domain capabilities of Modelica, Argonne National Laboratory, Idaho National Laboratory, and Oak Ridge National Laboratory are investigating the dynamics (e.g., thermal hydraulics and electrical generation/consumption) and cost of a hybrid system. This paper examines the NHES work underway, emphasizing the control system developed for individual subsystems and the overall supervisory control system.

  13. Modified quark-meson coupling model for nuclear matter

    International Nuclear Information System (INIS)

    Jin, X.; Jennings, B.K.

    1996-01-01

    The quark-meson coupling model for nuclear matter, which describes nuclear matter as nonoverlapping MIT bags bound by the self-consistent exchange of scalar and vector mesons, is modified by introducing medium modification of the bag constant. We model the density dependence of the bag constant in two different ways: One invokes a direct coupling of the bag constant to the scalar meson field, and the other relates the bag constant to the in-medium nucleon mass. Both models feature a decreasing bag constant with increasing density. We find that when the bag constant is significantly reduced in nuclear medium with respect to its free-space value, large canceling isoscalar Lorentz scalar and vector potentials for the nucleon in nuclear matter emerge naturally. Such potentials are comparable to those suggested by relativistic nuclear phenomenology and finite-density QCD sum rules. This suggests that the reduction of bag constant in nuclear medium may play an important role in low- and medium-energy nuclear physics. copyright 1996 The American Physical Society

  14. Infrastructure development assistance modeling for nuclear power plant

    International Nuclear Information System (INIS)

    Park, J. H.; Hwang, K.; Park, K. M.; Kim, S. W.; Lee, S. M.

    2012-01-01

    The purpose of this paper is to develop a model, a general frame to be utilized in assisting newcomer countries to start a nuclear power program. A nuclear power plant project involves technical complexity and high level of investment with long duration. Considering newcomers are mostly developing countries that lack the national infrastructure, key infrastructure issues may constitute the principal constraints to the development of a nuclear power program. In this regard, it is important to provide guidance and support to set up an appropriate infrastructure when we help them with the first launch of nuclear power plant project. To date, as a sole nuclear power generation company, KHNP has been invited many times to mentor or assist newcomer countries for their successful start of a nuclear power program since Republic of Korea is an exemplary case of a developing country which began nuclear power program from scratch and became a major world nuclear energy country in a short period of time. Through hosting events organized to aid newcomer countries' initiation of nuclear power projects, difficulties have been recognized. Each event had different contents according to circumstances because they were held as an unstructured and one-off thing. By developing a general model, we can give more adequate and effective aid in an efficient way. In this paper, we created a model to identify necessary infrastructures at the right stage, which was mainly based on a case of Korea. Taking into account the assistance we received from foreign companies and our own efforts for technological self-reliance, we have developed a general time table and specified activities required to do at each stage. From a donor's perspective, we explored various ways to help nuclear infrastructure development including technical support programs, training courses, and participating in IAEA technical cooperation programs on a regular basis. If we further develop the model, the next task would be to

  15. Infrastructure development assistance modeling for nuclear power plant

    Energy Technology Data Exchange (ETDEWEB)

    Park, J. H.; Hwang, K.; Park, K. M.; Kim, S. W.; Lee, S. M. [Korea Hydro and Nuclear Power Co., LTD, 23, 106 gil, Yeongdong-daero, Gangnam-gu, 153-791 (Korea, Republic of)

    2012-07-01

    The purpose of this paper is to develop a model, a general frame to be utilized in assisting newcomer countries to start a nuclear power program. A nuclear power plant project involves technical complexity and high level of investment with long duration. Considering newcomers are mostly developing countries that lack the national infrastructure, key infrastructure issues may constitute the principal constraints to the development of a nuclear power program. In this regard, it is important to provide guidance and support to set up an appropriate infrastructure when we help them with the first launch of nuclear power plant project. To date, as a sole nuclear power generation company, KHNP has been invited many times to mentor or assist newcomer countries for their successful start of a nuclear power program since Republic of Korea is an exemplary case of a developing country which began nuclear power program from scratch and became a major world nuclear energy country in a short period of time. Through hosting events organized to aid newcomer countries' initiation of nuclear power projects, difficulties have been recognized. Each event had different contents according to circumstances because they were held as an unstructured and one-off thing. By developing a general model, we can give more adequate and effective aid in an efficient way. In this paper, we created a model to identify necessary infrastructures at the right stage, which was mainly based on a case of Korea. Taking into account the assistance we received from foreign companies and our own efforts for technological self-reliance, we have developed a general time table and specified activities required to do at each stage. From a donor's perspective, we explored various ways to help nuclear infrastructure development including technical support programs, training courses, and participating in IAEA technical cooperation programs on a regular basis. If we further develop the model, the next task

  16. Testing the predictive power of nuclear mass models

    International Nuclear Information System (INIS)

    Mendoza-Temis, J.; Morales, I.; Barea, J.; Frank, A.; Hirsch, J.G.; Vieyra, J.C. Lopez; Van Isacker, P.; Velazquez, V.

    2008-01-01

    A number of tests are introduced which probe the ability of nuclear mass models to extrapolate. Three models are analyzed in detail: the liquid drop model, the liquid drop model plus empirical shell corrections and the Duflo-Zuker mass formula. If predicted nuclei are close to the fitted ones, average errors in predicted and fitted masses are similar. However, the challenge of predicting nuclear masses in a region stabilized by shell effects (e.g., the lead region) is far more difficult. The Duflo-Zuker mass formula emerges as a powerful predictive tool

  17. Development of real options model for nuclear power plants

    International Nuclear Information System (INIS)

    Ono, Kenji

    2004-01-01

    As the Japanese electricity market is deregulated, it becomes more important for electric utilities to recognize their financial risks and to adopt strategic and scientific decision making methodology. We have developed two models for valuation of Japanese nuclear power plants to support utilities' decision making. One is a net present value (NPV) model using discounted cash flow analysis method. Another is a real options model. This model is based on strict financial technology theory and can calculate value of early retirement, life extension and new unit addition options of nuclear units under electricity price uncertainty. This can also derive an optimal period for retirement, life extension and new unit addition. (author)

  18. Modeling the degradation of nuclear components

    International Nuclear Information System (INIS)

    Stock, D.; Samanta, P.; Vesely, W.

    1993-01-01

    This paper describes component level reliability models that use information on degradation to predict component reliability, and which have been used to evaluate different maintenance and testing policies. The models are based on continuous time Markov processes, and are a generalization of reliability models currently used in Probabilistic Risk Assessment. An explanation of the models, the model parameters, and an example of how these models can be used to evaluate maintenance policies are discussed

  19. Identification of a nuclear plant dynamics via ARMAX model

    International Nuclear Information System (INIS)

    Yamamoto, Shigeki; Otsuji, Tomoo; Muramatsu, Eiichi

    2000-01-01

    Dynamics of the reactor of nuclear ship 'Mutsu' is described by a linear time-invariant discrete-time model which is referred to as ARMAX (Auto-Regressive Moving Average eXogenious inputs) model. Applying system identification methods, parameters of the ARMAX model are determined from input-output data of the reactor. Accuracy of the model is examined in time and frequency domain. We show that the model can be a good approximation of the plant dynamics. (author)

  20. Mitochondrial cristae remodelling is associated with disrupted OPA1 oligomerisation in the Huntington's disease R6/2 fragment model.

    Science.gov (United States)

    Hering, Tanja; Kojer, Kerstin; Birth, Nathalie; Hallitsch, Jaqueline; Taanman, Jan-Willem; Orth, Michael

    2017-02-01

    There is evidence of an imbalance of mitochondrial fission and fusion in patients with Huntington's disease (HD) and HD animal models. Fission and fusion are important for mitochondrial homeostasis including mitochondrial DNA (mtDNA) maintenance and may be relevant for the selective striatal mtDNA depletion that we observed in the R6/2 fragment HD mouse model. We aimed to investigate the fission/fusion balance and the integrity of the mitochondrial membrane system in cortex and striatum of end-stage R6/2 mice and wild-type animals. Mitochondrial morphology was determined using electron microscopy, and transcript and protein levels of factors that play a key role in fission and fusion, including DRP1, mitofusin 1 and 2, mitofilin and OPA1, and cytochrome c and caspase 3 were assessed by RT-qPCR and immunoblotting. OPA1 oligomerisation was evaluated using blue native gels. In striatum and cortex of R6/2 mice, mitochondrial cristae morphology was abnormal. Mitofilin and the overall levels of the fission and fusion factors were unaffected; however, OPA1 oligomerisation was abnormal in striatum and cortex of R6/2 mice. Mitochondrial and cytoplasmic cytochrome c levels were similar in R6/2 and wild-type mice with no significant increase of activated caspase 3. Our results indicate that the integrity of the mitochondrial cristae is compromised in striatum and cortex of the R6/2 mice and that this is most likely caused by impaired OPA1 oligomerisation. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Modelling the distribution of the invasive Roesel’s bush-cricket (Metrioptera roeselii in a fragmented landscape

    Directory of Open Access Journals (Sweden)

    Sonja Preuss

    2011-11-01

    Full Text Available The development of conservation strategies to mitigate the impact of invasive species requires knowledge of the species ecology and distribution. This is, however, often lacking as collecting biological data may be both time-consuming and resource intensive. Species distribution models can offer a solution to this dilemma by analysing the species-environment relationship with help of Geographic information systems (GIS. In this study, we model the distribution of the non-native bush-cricket Metrioptera roeselii in the agricultural landscape in mid-Sweden where the species has been rapidly expanding in its range since the 1990s. We extract ecologically relevant landscape variables from Swedish CORINE land-cover maps and use species presence-absence data from large-scale surveys to construct a species distribution model (SDM. The aim of the study is to increase the knowledge of the species range expansion pattern by examining how its distribution is affected by landscape composition and structure, and to evaluate SDM performance at two different spatial scales. We found that models including data on a scale of 1 × 1 km were able to explain more of the variation in species distribution than those on the local scale (10 m buffer on each side of surveyed road. The amount of grassland in the landscape, estimated from the area of arable land, pasture and rural settlements, was a good predictor of the presence of the species on both scales. The measurements of landscape structure – linear elements and fragmentation - gave ambivalent results which differed from previous small scaled studies on species dispersal behaviour and occupancy patterns. The models had good predictive ability and showed that areas dominated by agricultural fields and their associated grassland edges have a high probability being colonised by the species. Our study identified important landscape variables that explain the distribution of M. roeselii in Mid-Sweden that may also

  2. A new statistical scission-point model fed with microscopic ingredients to predict fission fragments distributions; Developpement d'un nouveau modele de point de scission base sur des ingredients microscopiques

    Energy Technology Data Exchange (ETDEWEB)

    Heinrich, S

    2006-07-01

    Nucleus fission process is a very complex phenomenon and, even nowadays, no realistic models describing the overall process are available. The work presented here deals with a theoretical description of fission fragments distributions in mass, charge, energy and deformation. We have reconsidered and updated the B.D. Wilking Scission Point model. Our purpose was to test if this statistic model applied at the scission point and by introducing new results of modern microscopic calculations allows to describe quantitatively the fission fragments distributions. We calculate the surface energy available at the scission point as a function of the fragments deformations. This surface is obtained from a Hartree Fock Bogoliubov microscopic calculation which guarantee a realistic description of the potential dependence on the deformation for each fragment. The statistic balance is described by the level densities of the fragment. We have tried to avoid as much as possible the input of empirical parameters in the model. Our only parameter, the distance between each fragment at the scission point, is discussed by comparison with scission configuration obtained from full dynamical microscopic calculations. Also, the comparison between our results and experimental data is very satisfying and allow us to discuss the success and limitations of our approach. We finally proposed ideas to improve the model, in particular by applying dynamical corrections. (author)

  3. Large scale Bayesian nuclear data evaluation with consistent model defects

    International Nuclear Information System (INIS)

    Schnabel, G

    2015-01-01

    The aim of nuclear data evaluation is the reliable determination of cross sections and related quantities of the atomic nuclei. To this end, evaluation methods are applied which combine the information of experiments with the results of model calculations. The evaluated observables with their associated uncertainties and correlations are assembled into data sets, which are required for the development of novel nuclear facilities, such as fusion reactors for energy supply, and accelerator driven systems for nuclear waste incineration. The efficiency and safety of such future facilities is dependent on the quality of these data sets and thus also on the reliability of the applied evaluation methods. This work investigated the performance of the majority of available evaluation methods in two scenarios. The study indicated the importance of an essential component in these methods, which is the frequently ignored deficiency of nuclear models. Usually, nuclear models are based on approximations and thus their predictions may deviate from reliable experimental data. As demonstrated in this thesis, the neglect of this possibility in evaluation methods can lead to estimates of observables which are inconsistent with experimental data. Due to this finding, an extension of Bayesian evaluation methods is proposed to take into account the deficiency of the nuclear models. The deficiency is modeled as a random function in terms of a Gaussian process and combined with the model prediction. This novel formulation conserves sum rules and allows to explicitly estimate the magnitude of model deficiency. Both features are missing in available evaluation methods so far. Furthermore, two improvements of existing methods have been developed in the course of this thesis. The first improvement concerns methods relying on Monte Carlo sampling. A Metropolis-Hastings scheme with a specific proposal distribution is suggested, which proved to be more efficient in the studied scenarios than the

  4. A probabilistic model for US nuclear power construction times

    International Nuclear Information System (INIS)

    Shash, A.A.H.

    1988-01-01

    Construction time for nuclear power plants is an important element in planning for resources to meet future load demands. Analysis of actual versus estimated construction times for past US nuclear power plants indicates that utilities have continuously underestimated their power plants' construction durations. The analysis also indicates that the actual average construction time has been increasing upward, and the actual durations of power plants permitted to construct in the same year varied substantially. This study presents two probabilistic models for nuclear power construction time for use by the nuclear industry as estimating tool. The study also presents a detailed explanation of the factors that are responsible for increasing and varying nuclear power construction times. Observations on 91 complete nuclear units were involved in three interdependent analyses in the process of explanation and derivation of the probabilistic models. The historical data was first utilized in the data envelopment analysis (DEA) for the purpose of obtaining frontier index measures for project management achievement in building nuclear power plants

  5. A New Dynamic Model for Nuclear Fuel Cycle System Analysis

    International Nuclear Information System (INIS)

    Choi, Sungyeol; Ko, Won Il

    2014-01-01

    The evaluation of mass flow is a complex process where numerous parameters and their complex interaction are involved. Given that many nuclear power countries have light and heavy water reactors and associated fuel cycle technologies, the mass flow analysis has to consider a dynamic transition from the open fuel cycle to other cycles over decades or a century. Although an equilibrium analysis provides insight concerning the end-states of fuel cycle transitions, it cannot answer when we need specific management options, whether the current plan can deliver these options when needed, and how fast the equilibrium can be achieved. As a pilot application, the government brought several experts together to conduct preliminary evaluations for nuclear fuel cycle options in 2010. According to Table 1, they concluded that the closed nuclear fuel cycle has long-term advantages over the open fuel cycle. However, it is still necessary to assess these options in depth and to optimize transition paths of these long-term options with advanced dynamic fuel cycle models. A dynamic simulation model for nuclear fuel cycle systems was developed and its dynamic mass flow analysis capability was validated against the results of existing models. This model can reflects a complex combination of various fuel cycle processes and reactor types, from once-through to multiple recycling, within a single nuclear fuel cycle system. For the open fuel cycle, the results of the developed model are well matched with the results of other models

  6. Thermohydraulic tests in nuclear fuel model

    International Nuclear Information System (INIS)

    Ladeira, L.C.D.; Navarro, M.A.

    1984-01-01

    The main experimental works performed in the Thermohydraulics Laboratory of the NUCLEBRAS Nuclear Technology Development Center, in the field of thermofluodynamics are briefly described. These works include the performing of steady-state flow tests in single tube test sections, and the design and construction of a rod bundle test section, which will be also used for those kind of testes. Mention is made of the works to be performed in the near future, related to steady-state and transient flow tests. (Author) [pt

  7. Models of high energy nuclear collisions

    International Nuclear Information System (INIS)

    Glendenning, N.K.

    1978-06-01

    The discussion covers nuclear collisions at relativistic energies including classes of high energy nucleus--nucleus collisions, and the kinetics of a central collision; and the asymptotic hadron spectrum including known and unknown hadrons, the relevance of the spectrum and the means of its study, thermodynamics of hadronic matter, examples of hadronic spectra, the temperature, composition of the initial fireball and its expansion, isoergic expansion with no pre-freezeout radiation, isentropic expansion of the fireball, the quasi-dynamical expansion, and finally antinuclei, hypernuclei, and the quark phase. 28 references

  8. Radiation Damage in Nuclear Fuel for Advanced Burner Reactors: Modeling and Experimental Validation

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Niels Gronbech; Asta, Mark; Ozolins, Nigel Browning' Vidvuds; de Walle, Axel van; Wolverton, Christopher

    2011-12-29

    The consortium has completed its existence and we are here highlighting work and accomplishments. As outlined in the proposal, the objective of the work was to advance the theoretical understanding of advanced nuclear fuel materials (oxides) toward a comprehensive modeling strategy that incorporates the different relevant scales involved in radiation damage in oxide fuels. Approaching this we set out to investigate and develop a set of directions: 1) Fission fragment and ion trajectory studies through advanced molecular dynamics methods that allow for statistical multi-scale simulations. This work also includes an investigation of appropriate interatomic force fields useful for the energetic multi-scale phenomena of high energy collisions; 2) Studies of defect and gas bubble formation through electronic structure and Monte Carlo simulations; and 3) an experimental component for the characterization of materials such that comparisons can be obtained between theory and experiment.

  9. Localization by whole-body autoradiography of intact and fragmented radiolabeled antibodies in a metastatic human colonic cancer model

    International Nuclear Information System (INIS)

    Fand, Irwin; Sharkey, R.M.; Grundy, J.P.; Goldenberg, D.M.

    1992-01-01

    In this report, we have employed macroautoradiography to compare the tumor targeting of 125 I-labeled anti-carcinoembryonic antigen (CEA) MAb (NP-4) to 125 I-labeled anti-colon-specific antigen-p (CSAp) MAb (Mu-9) and their labeled F(ab') 2 and Fab' fragments, in nude mice each bearing large dorsal human colonic tumor xenografts, and small nodular tumors in the liver and lungs. Using intact MAbs (NP-4 and Mu-9), clearance of background radioactivity was delayed to 3-7 days post-treatment. Treatment with F(ab') 2 and Fab' fragments of both NP-4 and Mu-9 MAbs, however, promoted clearance of background 125 I-radioactivity which was well advanced by 6-24 h and complete by 24-48 h after injection. Localization of 125 I-radioactivity in large and micrometastatic tumor perimeters was the most characteristic uptake pattern observed for both intact and fragmented MAbs. Qualitative analysis of macroautoradiographic images and quantitative densitometry indicated that the higher tumor-to-blood ratios achieved with labeled F(ab') 2 and Fab' fragments at early time points, compared to labeled whole immunoglobulin, appeared to be more a function of rapid plasma clearance, tumor mass, location of xenografts and specific tumor growth patterns than increased tumor penetrance by lower molecular weight univalent and bivalent immune fragments. (Author)

  10. Modeling of the core of Atucha II nuclear power plant

    International Nuclear Information System (INIS)

    Blanco, Anibal

    2007-01-01

    This work is part of a Nuclear Engineer degree thesis of the Instituto Balseiro and it is carried out under the development of an Argentinean Nuclear Power Plant Simulator. To obtain the best representation of the reactor physical behavior using the state of the art tools this Simulator should couple a 3D neutronics core calculation code with a thermal-hydraulics system code. Focused in the neutronic nature of this job, using PARCS, we modeled and performed calculations of the nuclear power plant Atucha 2 core. Whenever it is possible, we compare our results against results obtained with PUMA (the official core code for Atucha 2). (author) [es

  11. Methodology and preliminary models for analyzing nuclear-safeguards decisions

    International Nuclear Information System (INIS)

    Judd, B.R.; Weissenberger, S.

    1978-11-01

    This report describes a general analytical tool designed with Lawrence Livermore Laboratory to assist the Nuclear Regulatory Commission in making nuclear safeguards decisions. The approach is based on decision analysis - a quantitative procedure for making decisions under uncertain conditions. The report: describes illustrative models that quantify the probability and consequences of diverted special nuclear material and the costs of safeguarding the material; demonstrates a methodology for using this information to set safeguards regulations (safeguards criteria); and summarizes insights gained in a very preliminary assessment of a hypothetical reprocessing plant

  12. Fragmentation of water on swift {sup 3}He{sup 2+} ion impact

    Energy Technology Data Exchange (ETDEWEB)

    Sabin, John R. [Quantum Theory Project, Departments of Chemistry and Physics, P.O. Box 118435, University of Florida, Gainesville, FL 32611-8435 (United States); Institut for Fysik og Kemi, Suddansk Universitet, 5230 Odense M (Denmark)], E-mail: sabin@qtp.ufl.edu; Cabrerra-Trujillo, Remigio [Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Apartado Postal 48-3, Cuernavaca, Morelos 62251 (Mexico); Stolterfoht, Nikolaus [Hahn-Meitner Institut, Glienickerstrasse 100, D-14109 Berlin (Germany); Deumens, Erik; Ohrn, Yngve [Quantum Theory Project, Departments of Chemistry and Physics, P.O. Box 118435, University of Florida, Gainesville, FL 32611-8435 (United States)

    2009-01-15

    Charge exchange and fragmentation are the usual results in ion-molecule collision systems, and the specifics of the fragmentation process determine the chemical destiny of the target system. In this paper, we report recent progress on calculations of the fragmentation patterns for the model system He{sup 2+} + H{sub 2}O for projectile energies of a few keV. The calculations are obtained using the electron-nuclear dynamics (END) method for solution of the time-dependent Schroedinger equation.

  13. Fission fragment yields from heavy-ion-induced reactions measured with a fragment separator

    Science.gov (United States)

    Tarasov, O. B.; Delaune, O.; Farget, F.; Morrissey, D. J.; Amthor, A. M.; Bastin, B.; Bazin, D.; Blank, B.; Cacéres, L.; Chbihi, A.; Fernández-Dominguez, B.; Grévy, S.; Kamalou, O.; Lukyanov, S. M.; Mittig, W.; Pereira, J.; Perrot, L.; Saint-Laurent, M.-G.; Savajols, H.; Sherrill, B. M.; Stodel, C.; Thomas, J. C.; Villari, A. C.

    2018-04-01

    The systematic study of fission fragment yields under different initial conditions has provided valuable experimental data for benchmarking models of fission product yields. Nuclear reactions using inverse kinematics coupled to the use of a high-resolution spectrometer with good fragment identification are shown here to be a powerful tool to measure the inclusive isotopic yields of fission fragments. In-flight fusion-fission was used in this work to produce secondary beams of neutron-rich isotopes in the collisions of a 238U beam at 24 MeV/u with 9Be and 12C targets at GANIL using the LISE3 fragment separator. Unique identification of the A, Z, and atomic charge state, q, of fission products was attained with the Δ E- TKE-B ρ- ToF measurement technique. Mass, and atomic number distributions are reported for the two reactions. The results show the importance of different reaction mechanisms in the two cases. The optimal target material for higher yields of neutron-rich high- Z isotopes produced in fusion-fission reactions as a function of projectile energy is discussed.

  14. Correlations between isospin dynamics and Intermediate Mass Fragments emission time scales: a probe for the symmetry energy in asymmetric nuclear matter

    International Nuclear Information System (INIS)

    De Filippo, E; Cardella, G; Guidara, E La; Pagano, A; Papa, M; Amorini, F; Colonna, M; Gianì, S; Grassi, L; Han, J; Maiolino, C; Auditore, L; Minniti, T; Baran, V; Berceanu, I; Geraci, E; Grzeszczuk, A; Guazzoni, P; Lanzalone, G; Lombardo, I

    2013-01-01

    We show new data from the 64 Ni+ 124 Sn and 58 Ni+ 112 Sn reactions studied in direct kinematics with the CHIMERA detector at INFN-LNS and compared with the reverse kinematics reactions at the same incident beam energy (35 A MeV). Analyzing the data with the method of relative velocity correlations, fragments coming from statistical decay of an excited projectile-like (PLF) or target-like (TLF) fragments are discriminated from the ones coming from dynamical emission in the early stages of the reaction. By comparing data of the reverse kinematics experiment with a stochastic mean field (SMF) + GEMINI calculations our results show that observables from neck fragmentation mechanism add valuable constraints on the density dependence of symmetry energy. An indication is found for a moderately stiff symmetry energy potential term of EOS.

  15. The Zero-Degree Detector system for fragmentation studies

    International Nuclear Information System (INIS)

    Adams, J.H.; Christl, M.J.; Howell, L.W.; Kuznetsov, E.

    2007-01-01

    The measurement of nuclear fragmentation cross-sections requires the detection and identification of individual projectile fragments. If light and heavy fragments are recorded in the same detector, it may be impossible to distinguish the signal from the light fragment. To overcome this problem, we have developed the Zero-degree Detector System (ZDDS). The ZDDS enables the measurement of cross-sections for light fragment production by using pixelated detectors to separately measure the signals of each fragment. The system has been used to measure the fragmentation of beams as heavy as Fe at the NASA Space Radiation Laboratory at Brookhaven National Laboratory and the Heavy Ion Medical Accelerator in Chiba, Japan

  16. A nuclear data acquisition system flow control model

    International Nuclear Information System (INIS)

    Hack, S.N.

    1988-01-01

    A general Petri Net representation of a nuclear data acquisition system model is presented. This model provides for the unique requirements of a nuclear data acquisition system including the capabilities of concurrently acquiring asynchronous and synchronous data, of providing multiple priority levels of flow control arbitration, and of permitting multiple input sources to reside at the same priority without the problem of channel lockout caused by a high rate data source. Finally, a previously implemented gamma camera/physiological signal data acquisition system is described using the models presented

  17. Loss of laforin or malin results in increased Drp1 level and concomitant mitochondrial fragmentation in Lafora disease mouse models.

    Science.gov (United States)

    Upadhyay, Mamta; Agarwal, Saloni; Bhadauriya, Pratibha; Ganesh, Subramaniam

    2017-04-01

    Lafora disease (LD) is an autosomal recessive form of a fatal disorder characterized by the myoclonus epilepsy, ataxia, psychosis, dementia, and dysarthria. A hallmark of LD is the presence of abnormal glycogen inclusions called Lafora bodies in the affected tissues including the neurons. LD can be caused by defects either in the laforin phosphatase coded by the EPM2A gene or in the malin E3 ubiquitin ligase coded by the NHLRC1 gene. The mouse models of LD, created by the targeted disruption of the LD genes, display several neurodegenerative changes. Prominent among them are the autophagic defects, abnormally large lysosomes, neurofibrillary tangles, amyloid beta deposits, and abnormal mitochondria. However, whether or not such neurodegenerative changes are a direct effect of the loss of laforin/malin was not unequivocally established. Here, we show that laforin- or malin-deficient neurons and fibroblasts display a significantly higher number of fragmented mitochondria. Loss of laforin or malin resulted in increased levels of the mitochondrial fission GTPase Drp1, its enhanced mitochondrial targeting, and increased intracellular calcium levels. Intriguingly, laforin and malin display opposite effects on the cellular level of parkin, an ubiquitin ligase of Drp1; loss of laforin led to reduced levels of parkin while the loss of malin resulted in increased parkin levels. Laforin and malin, however, interact with and positively regulate the activity of parkin, thus explaining the molecular basis of increased Drp1 levels in LD tissues. Our results suggest that laforin and malin are novel regulators of mitochondrial quality control pathway and that the mitochondrial dysfunction resulting from the increased Drp1 levels could underlie neuropathology in LD. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Process of Fragment-Based Lead Discovery—A Perspective from NMR

    Directory of Open Access Journals (Sweden)

    Rongsheng Ma

    2016-07-01

    Full Text Available Fragment-based lead discovery (FBLD has proven fruitful during the past two decades for a variety of targets, even challenging protein–protein interaction (PPI systems. Nuclear magnetic resonance (NMR spectroscopy plays a vital role, from initial fragment-based screening to lead generation, because of its power to probe the intrinsically weak interactions between targets and low-molecular-weight fragments. Here, we review the NMR FBLD process from initial library construction to lead generation. We describe technical aspects regarding fragment library design, ligand- and protein-observed screening, and protein–ligand structure model generation. For weak binders, the initial hit-to-lead evolution can be guided by structural information retrieved from NMR spectroscopy, including chemical shift perturbation, transferred pseudocontact shifts, and paramagnetic relaxation enhancement. This perspective examines structure-guided optimization from weak fragment screening hits to potent leads for challenging PPI targets.

  19. Development of ITER 3D neutronics model and nuclear analyses

    International Nuclear Information System (INIS)

    Zeng, Q.; Zheng, S.; Lu, L.; Li, Y.; Ding, A.; Hu, H.; Wu, Y.

    2007-01-01

    ITER nuclear analyses rely on the calculations with the three-dimensional (3D) Monte Carlo code e.g. the widely-used MCNP. However, continuous changes in the design of the components require the 3D neutronics model for nuclear analyses should be updated. Nevertheless, the modeling of a complex geometry with MCNP by hand is a very time-consuming task. It is an efficient way to develop CAD-based interface code for automatic conversion from CAD models to MCNP input files. Based on the latest CAD model and the available interface codes, the two approaches of updating 3D nuetronics model have been discussed by ITER IT (International Team): The first is to start with the existing MCNP model 'Brand' and update it through a combination of direct modification of the MCNP input file and generation of models for some components directly from the CAD data; The second is to start from the full CAD model, make the necessary simplifications, and generate the MCNP model by one of the interface codes. MCAM as an advanced CAD-based MCNP interface code developed by FDS Team in China has been successfully applied to update the ITER 3D neutronics model by adopting the above two approaches. The Brand model has been updated to generate portions of the geometry based on the newest CAD model by MCAM. MCAM has also successfully performed conversion to MCNP neutronics model from a full ITER CAD model which is simplified and issued by ITER IT to benchmark the above interface codes. Based on the two updated 3D neutronics models, the related nuclear analyses are performed. This paper presents the status of ITER 3D modeling by using MCAM and its nuclear analyses, as well as a brief introduction of advanced version of MCAM. (authors)

  20. Validating neural-network refinements of nuclear mass models

    Science.gov (United States)

    Utama, R.; Piekarewicz, J.

    2018-01-01

    Background: Nuclear astrophysics centers on the role of nuclear physics in the cosmos. In particular, nuclear masses at the limits of stability are critical in the development of stellar structure and the origin of the elements. Purpose: We aim to test and validate the predictions of recently refined nuclear mass models against the newly published AME2016 compilation. Methods: The basic paradigm underlining the recently refined nuclear mass models is based on existing state-of-the-art models that are subsequently refined through the training of an artificial neural network. Bayesian inference is used to determine the parameters of the neural network so that statistical uncertainties are provided for all model predictions. Results: We observe a significant improvement in the Bayesian neural network (BNN) predictions relative to the corresponding "bare" models when compared to the nearly 50 new masses reported in the AME2016 compilation. Further, AME2016 estimates for the handful of impactful isotopes in the determination of r -process abundances are found to be in fairly good agreement with our theoretical predictions. Indeed, the BNN-improved Duflo-Zuker model predicts a root-mean-square deviation relative to experiment of σrms≃400 keV. Conclusions: Given the excellent performance of the BNN refinement in confronting the recently published AME2016 compilation, we are confident of its critical role in our quest for mass models of the highest quality. Moreover, as uncertainty quantification is at the core of the BNN approach, the improved mass models are in a unique position to identify those nuclei that will have the strongest impact in resolving some of the outstanding questions in nuclear astrophysics.

  1. Nuclear reactor power control system based on flexibility model

    International Nuclear Information System (INIS)

    Li Gang; Zhao Fuyu; Li Chong; Tai Yun

    2011-01-01

    Design the nuclear reactor power control system in this paper to cater to a nonlinear nuclear reactor. First, calculate linear power models at five power levels of the reactor as five local models and design controllers of the local models as local controllers. Every local controller consists of an optimal controller contrived by the toolbox of Optimal Controller Designer (OCD) and a proportion-integration-differentiation (PID) controller devised via Genetic Algorithm (GA) to set parameters of the PID controller. According to the local models and controllers, apply the principle of flexibility model developed in the paper to obtain the flexibility model and the flexibility controller at every power level. Second, the flexibility model and the flexibility controller at a level structure the power control system of this level. The set of the whole power control systems corresponding to global power levels is to approximately carry out the power control of the reactor. Finally, the nuclear reactor power control system is simulated. The simulation result shows that the idea of flexibility model is feasible and the nuclear reactor power control system is effective. (author)

  2. Modeling the optimal management of spent nuclear fuel

    International Nuclear Information System (INIS)

    Nachlas, J.A.; Kurstedt, H.A. Jr.; Swindle, D.W. Jr.; Korcz, K.O.

    1977-01-01

    Recent governmental policy decisions dictate that strategies for managing spent nuclear fuel be developed. Two models are constructed to investigate the optimum residence time and the optimal inventory withdrawal policy for fuel material that presently must be stored. The mutual utility of the models is demonstrated through reference case application

  3. ENVI Model Development for Korean Nuclear Spent Fuel Options Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Sunyoung; Jeong, Yon Hong; Han, Jae-Jun; Lee, Aeri; Hwang, Yong-Soo [Korea Institute of Nuclear Nonproliferation and Control, Daejeon (Korea, Republic of)

    2015-10-15

    The disposal facility of the spent nuclear fuel will be operated from 2051. This paper presents the ENVI code developed by GoldSim Software to simulate options for managing spent nuclear fuel (SNF) in South Korea. The ENVI is a simulator to allow decision-makers to assist to evaluate the performance for spent nuclear fuel management. The multiple options for managing the spent nuclear fuel including the storage and transportation are investigated into interim storage, permanent disposal in geological repositories and overseas and domestic reprocessing. The ENVI code uses the GoldSim software to simulate the logistics of the associated activities. The result by the ENVI model not only produces the total cost to compare among the multiple options but also predict the sizes and timings of different facilities required. In order to decide the policy for spent nuclear management this purpose of this paper is to draw the optimum management plan to solve the nuclear spent fuel issue in the economical aspects. This paper is focused on the development of the ENVI's logic and calculations to simulate four options(No Reprocessing, Overseas Reprocessing, Domestic Reprocessing, and Overseas and Domestic Reprocessing) for managing the spent nuclear fuel in South Korea. The time history of the spent nuclear fuel produced from both the existing and future NPP's can be predicted, based on the Goldsim software made available very user friendly model. The simulation result will be used to suggest the strategic plans for the spent nuclear fuel management.

  4. ENVI Model Development for Korean Nuclear Spent Fuel Options Analysis

    International Nuclear Information System (INIS)

    Chang, Sunyoung; Jeong, Yon Hong; Han, Jae-Jun; Lee, Aeri; Hwang, Yong-Soo

    2015-01-01

    The disposal facility of the spent nuclear fuel will be operated from 2051. This paper presents the ENVI code developed by GoldSim Software to simulate options for managing spent nuclear fuel (SNF) in South Korea. The ENVI is a simulator to allow decision-makers to assist to evaluate the performance for spent nuclear fuel management. The multiple options for managing the spent nuclear fuel including the storage and transportation are investigated into interim storage, permanent disposal in geological repositories and overseas and domestic reprocessing. The ENVI code uses the GoldSim software to simulate the logistics of the associated activities. The result by the ENVI model not only produces the total cost to compare among the multiple options but also predict the sizes and timings of different facilities required. In order to decide the policy for spent nuclear management this purpose of this paper is to draw the optimum management plan to solve the nuclear spent fuel issue in the economical aspects. This paper is focused on the development of the ENVI's logic and calculations to simulate four options(No Reprocessing, Overseas Reprocessing, Domestic Reprocessing, and Overseas and Domestic Reprocessing) for managing the spent nuclear fuel in South Korea. The time history of the spent nuclear fuel produced from both the existing and future NPP's can be predicted, based on the Goldsim software made available very user friendly model. The simulation result will be used to suggest the strategic plans for the spent nuclear fuel management

  5. Mild aerobic exercise blocks elastin fiber fragmentation and aortic dilatation in a mouse model of Marfan syndrome associated aortic aneurysm.

    Science.gov (United States)

    Gibson, Christine; Nielsen, Cory; Alex, Ramona; Cooper, Kimbal; Farney, Michael; Gaufin, Douglas; Cui, Jason Z; van Breemen, Cornelis; Broderick, Tom L; Vallejo-Elias, Johana; Esfandiarei, Mitra

    2017-07-01

    Regular low-impact physical activity is generally allowed in patients with Marfan syndrome, a connective tissue disorder caused by heterozygous mutations in the fibrillin-1 gene. However, being above average in height encourages young adults with this syndrome to engage in high-intensity contact sports, which unfortunately increases the risk for aortic aneurysm and rupture, the leading cause of death in Marfan syndrome. In this study, we investigated the effects of voluntary (cage-wheel) or forced (treadmill) aerobic exercise at different intensities on aortic function and structure in a mouse model of Marfan syndrome. Four-week-old Marfan and wild-type mice were subjected to voluntary and forced exercise regimens or sedentary lifestyle for 5 mo. Thoracic aortic tissue was isolated and subjected to structural and functional studies. Our data showed that exercise improved aortic wall structure and function in Marfan mice and that the beneficial effect was biphasic, with an optimum at low intensity exercise (55-65% V̇o 2max ) and tapering off at a higher intensity of exercise (85% V̇o 2max ). The mechanism underlying the reduced elastin fragmentation in Marfan mice involved reduction of the expression of matrix metalloproteinases 2 and 9 within the aortic wall. These findings present the first evidence of potential beneficial effects of mild exercise on the structural integrity of the aortic wall in Marfan syndrome associated aneurysm. Our finding that moderate, but not strenuous, exercise protects aortic structure and function in a mouse model of Marfan syndrome could have important implications for the medical care of young Marfan patients. NEW & NOTEWORTHY The present study provides conclusive scientific evidence that daily exercise can improve aortic health in a mouse model of Marfan syndrome associated aortic aneurysm, and it establishes the threshold for the exercise intensity beyond which exercise may not be as protective. These findings establish a platform

  6. Study of stochastic approaches of the n-bodies problem: application to the nuclear fragmentation; Etude des approches stochastiques du probleme a N corps: application a la multifragmentation nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Guarnera, A.

    1996-07-09

    In the last decade nuclear physics research has found, with the observation of phenomena such as multifragmentation or vaporization, the possibility to get a deeper insight into the nuclear matter phase diagram. For example, a spinodal decomposition scenario has been proposed to explain the multifragmentation: because of the initial compression, the system may enter a region, the spinodal zone, in which the nuclear matter is no longer stable, and so any fluctuation leads to the formation of fragments. This thesis deals with spinodal decomposition within the theoretical framework of stochastic mean filed approaches, in which the one-body density function may experience a stochastic evolution. We have shown that these approaches are able to describe phenomena, such as first order phase transitions, in which fluctuations and many-body correlations plan an important role. In the framework of stochastic mean-filed approaches we have shown that the fragment production by spinodal decomposition is characterized by typical time scales of the order of 100 fm/c and by typical size scales around the Neon mass. We have also shown that these features are robust and that they are not affected significantly by a possible expansion of the system or by the finite size of nuclei. We have proposed as a signature of the spinodal decomposition some typical partition of the largest fragments. The study and the comparison with experimental data, performed for the reactions Xe + Cu at 45 MeV/A and Xe + Sn at 50 MeV/A, have shown a remarkable agreement. Moreover we would like to stress that the theory does not contain any adjustable parameter. These results seem to give a strong indication of the possibility to observe a spinodal decomposition of nuclei. (author).

  7. Model integration and the economics of nuclear power

    International Nuclear Information System (INIS)

    Lundgren, S.

    1985-01-01

    The author proposes and applies a specific approach to model integration, i.e. the merger of two or several independently developed models. The approach is intended for integrations of activity analysis sector models and applied general equilibrium models. Model integration makes it possible to extend the range of applicability of applied general equilibrium models by exploiting the information contained in sector models. It also makes it possible to evaluate the validity of the partial equilibrium analyses in which sector models often are employed. The proposed approach is used to integrate a sector model of electricity and heat production with a general equilibrium model of the Swedish economy. Both models have been constructed within the research programme. The author uses the integrated model to look at two issues concerning the role of nuclear power on the Swedish electricity market: What are the likely consequences of a nuclear power discontinuation and how does the nuclear power investment programme of the 1970's and the early 1980's compare with a socially efficient one. (Author)

  8. Nuclear surface vibrations in bag models

    International Nuclear Information System (INIS)

    Tomio, L.

    1984-01-01

    The main difficulties found in the hadron bag models are reviewed from the original version of the MIT bag model. Following, with the aim to answer two of the main difficulties in bag models, viz., the parity and the divergence illness, a dynamical model is presented. In the model, the confinement surface of the quarks (bag) is treated like a real physical object which interacts with the quarks and is exposed to vibrations. The model is applied to the nucleon, being observed that his spectrum, in the first excited levels, can be reproduced with resonable precision and obeying to the correct parity order. In the same way that in a similar work of Brown et al., it is observed to be instrumental the inclusion of the effect due to pions. (L.C.) [pt

  9. Schematic model of nuclear spin excitations

    International Nuclear Information System (INIS)

    Boucher, P.M.

    1990-01-01

    A simple model to estimate the strength of spin and nonspin collective states is presented. The model was inspired by early schematic models based on energy-weighted sum rules and is a useful tool for interpreting experimental data without the complexities of realistic microscopic calculations. The strength of collective states is calculated by assuming that a single collective state completely exhausts the energy-weighted sum rule. 19 refs

  10. Health effects models for nuclear power plant accident consequence analysis

    International Nuclear Information System (INIS)

    Abrahamson, S.; Bender, M.A.; Boecker, B.B.; Scott, B.R.

    1993-05-01

    The Nuclear Regulatory Commission (NRC) has sponsored several studies to identify and quantify, through the use of models, the potential health effects of accidental releases of radionuclides from nuclear power plants. The Reactor Safety Study provided the basis for most of the earlier estimates related to these health effects. Subsequent efforts by NRC-supported groups resulted in improved health effects models that were published in the report entitled open-quotes Health Effects Models for Nuclear Power Plant Consequence Analysisclose quotes, NUREG/CR-4214, 1985 and revised further in the 1989 report NUREG/CR-4214, Rev. 1, Part 2. The health effects models presented in the 1989 NUREG/CR-4214 report were developed for exposure to low-linear energy transfer (LET) (beta and gamma) radiation based on the best scientific information available at that time. Since the 1989 report was published, two addenda to that report have been prepared to (1) incorporate other scientific information related to low-LET health effects models and (2) extend the models to consider the possible health consequences of the addition of alpha-emitting radionuclides to the exposure source term. The first addendum report, entitled open-quotes Health Effects Models for Nuclear Power Plant Accident Consequence Analysis, Modifications of Models Resulting from Recent Reports on Health Effects of Ionizing Radiation, Low LET Radiation, Part 2: Scientific Bases for Health Effects Models,close quotes was published in 1991 as NUREG/CR-4214, Rev. 1, Part 2, Addendum 1. This second addendum addresses the possibility that some fraction of the accident source term from an operating nuclear power plant comprises alpha-emitting radionuclides. Consideration of chronic high-LET exposure from alpha radiation as well as acute and chronic exposure to low-LET beta and gamma radiations is a reasonable extension of the health effects model

  11. Anti-colchicine Fab fragments prevent lethal colchicine toxicity in a porcine model: a pharmacokinetic and clinical study.

    Science.gov (United States)

    Eddleston, Michael; Fabresse, Nicolas; Thompson, Adrian; Al Abdulla, Ibrahim; Gregson, Rachael; King, Tim; Astier, Alain; Baud, Frederic J; Clutton, R Eddie; Alvarez, Jean-Claude

    2018-08-01

    Colchicine poisoning is commonly lethal. Colchicine-specific Fab fragments increase rat urinary colchicine clearance and have been associated with a good outcome in one patient. We aimed to develop a porcine model of colchicine toxicity to study the pharmacokinetics and efficacy of ovine Fab. A Göttingen minipig critical care model was established and serial blood samples taken for colchicine and Fab pharmacokinetics, clinical chemistry, and haematology. Animals were euthanised when the mean arterial pressure fell below 45 mmHg without response to vasopressor, or at study completion. Initial studies indicated that oral dosing produced variable pharmacokinetics and time-to-euthanasia. By contrast, intravenous infusion of 0.25 mg/kg colchicine over 1 h produced reproducible pharmacokinetics (AUC 0-20 343 [SD = 21] µg/L/h), acute multi-organ injury, and cardiotoxicity requiring euthanasia a mean of 22.5 (SD = 3.2) h after dosing. A full-neutralising equimolar Fab dose given 6 h after the infusion (50% first hour, 50% next 6 h [to reduce renal-loss of unbound Fab]) produced a 7.35-fold increase in plasma colchicine (AUC 0-20 2,522 [SD = 14] µg/L/h), and removed all free plasma colchicine, but did not prevent toxicity (euthanasia at 29.1 [SD = 3.4] h). Earlier administration over 1 h of the full-neutralising dose, 1 or 3 h after the colchicine, produced a 12.9-fold (AUC 0-20 4,433 [SD = 607] µg/L/h) and 6.0-fold (AUC 0-20 2,047 [SD = 51] µg/L/h) increase in plasma colchicine, respectively, absence of free plasma colchicine until 20 h, and survival to study end without marked cardiotoxicity. Colchicine-specific Fab given early, in equimolar dose, bound colchicine, eliciting its movement into the blood, and preventing severe toxicity. Clinical studies are now needed to determine how soon this antidote must be given to work in human poisoning.

  12. Relationship between Disease Activity and Circulating Level of Collagen II C-Telopeptide Fragments in Papain Induced Osteoarthritis Rat Model

    Directory of Open Access Journals (Sweden)

    Humaira Majeed Khan

    2014-01-01

    Full Text Available Osteoarthritis (OA is a progressive degeneration of articular cartilage leading to failure in functional mobility of joints. It is characterized by morphological, biochemical and molecular changes in histology of cartilage. Different biological markers are used as indicators to precisely predict the stage of cartilage destruction of joints in OA patients and to evaluate the therapeutic efficacy of drugs used for OA. The present research was chalked out to establish relationship between disease activity and serum level of C-terminal telopeptide of type II collagen (CTX-II in experimentally induced OA rat model. Out of 30 male Wistar rats, 25 were used to induce OA by injecting papain (10mg/0.5mL of 0.05M sodium acetate in right knee joints whereas five (control were injected with sterile normal saline solution on day 0. Blood samples (5mL each were collected on weekly basis up to 28th days of post papain injection. Sera were separated and subjected to perform ELISA for estimating CTX-II fragments as cartilage biomarker (CartiLaps ® ELISA kit in experimental groups. Maximum level of CTX–II (pg/mL (40.44±3.07 was observed in sera samples of day 14 post papain injection followed by days 21 (40.22±2.01, 28 (36.82±3.81, 7 (34.48±4.17, 1 (15.08±4.22 and day 0 (2.55±0.10. The early changes in serum CTX-II from day 0 to 14 showed significant association with cartilage damage. Later on, no significant difference was observed in CTX-II level on day 14, 21 and 28 post papain injection. It is concluded that elevation in serum CTX-II level was concomitant with the onset of disease and degradation of cartilage. Moreover, CTX-II is a sensitive diagnostic biomarker to monitor joint disorder severity in papain induced OA rat experimental model on different days. These findings may be used as base line for early diagnosis of disease and initiation of therapy for successful outcome.

  13. Nuclear facility safeguards systems modeling using discrete event simulation

    International Nuclear Information System (INIS)

    Engi, D.

    1977-01-01

    The threat of theft or dispersal of special nuclear material at a nuclear facility is treated by studying the temporal relationships between adversaries having authorized access to the facility (insiders) and safeguards system events by using a GASP IV discrete event simulation. The safeguards system events--detection, assessment, delay, communications, and neutralization--are modeled for the general insider adversary strategy which includes degradation of the safeguards system elements followed by an attempt to steal or disperse special nuclear material. The performance measure used in the analysis is the estimated probability of safeguards system success in countering the adversary based upon a predetermined set of adversary actions. An exemplary problem which includes generated results is presented for a hypothetical nuclear facility. The results illustrate representative information that could be utilized by safeguards decision-makers

  14. The dynamics of fragment formation

    International Nuclear Information System (INIS)

    Keane, D.

    1994-09-01

    We demonstrate that in the Quantum Molecular Dynamics model, dynamical correlations can result in the production rate for final state nucleon clusters (and hence composite fragments) being higher than would be expected if statistics and the available phase space were dominant in determining composite formation. An intranuclear cascade or a Boltzmann-Uehling-Uhlenbeck model, combined with a statistical approach in the late stage of the collision to determine composites, provides an equivalent description only under limited conditions of centrality and beam energy. We use data on participant fragment production in Au + Au collisions in the Bevalac's BOS time projection chamber to map out the parameter space where statistical clustering provides a good description. In particular, we investigate momentum-space densities of fragments up to 4 He as a function of fragment transverse momentum, azimuth relative to the reaction plane, rapidity, multiplicity and beam energy

  15. Application of sequential fragmentation/transport theory to deposits of 1723 and 1963-65 eruptions of Volcan Irazu, Costa Rica: positive dispersion case and fractal model

    International Nuclear Information System (INIS)

    Brenes, Jose; Alvarado, Guillermo E.

    2013-01-01

    The theory of Fragmentation and Sequential Transport (FST) was applied to the granulometric analyzes of the deposits from the eruptions of 1723 and 1963-65 of the Volcan Irazu. An appreciable number of cases of positive dispersion was showed, associated in the literature with aggregation processes. A new fractal dimension defined in research has shown to be the product of secondary fragmentation. The application of the new dimension is used in the analyses of the eruptions of 1723 and 1963-65. A fractal model of a volcanic activity is formulated for the first time. The Hurst coefficient and the exponent of the law of powers are incorporated. The existence of values of dissidence near zero have been indicators of an effusive process, as would be the lava pools. The results derived from the model were agreed with field observations. (author) [es

  16. Numerical simulation of interior flow field of nuclear model pump

    International Nuclear Information System (INIS)

    Wang Chunlin; Peng Na; Kang Can; Zhao Baitong; Zhang Hao

    2009-01-01

    Reynolds time-averaged N-S equations and the standard k-ε turbulent model were adopted, and three-dimensional non-structural of tetrahedral mesh division was used for modeling. Multiple reference frame model of rotating fluid mechanical model was used, under the design condition, the three-dimensional incompressible turbulent flow of nuclear model pump was simulated, and the results preferably post the characteristics of the interior flow field. This paper first analyzes the total pressure and velocity distribution in the flow field, and then describes the interior flow field characteristics of each part such as the impeller, diffuser and spherical shell, and also discusses the reasons that cause these characteristics. The study results can be used to estimate the performance of nuclear model pump, and will provide some useful references for its hydraulic optimized design. (authors)

  17. Self-consistent mean-field models for nuclear structure

    International Nuclear Information System (INIS)

    Bender, Michael; Heenen, Paul-Henri; Reinhard, Paul-Gerhard

    2003-01-01

    The authors review the present status of self-consistent mean-field (SCMF) models for describing nuclear structure and low-energy dynamics. These models are presented as effective energy-density functionals. The three most widely used variants of SCMF's based on a Skyrme energy functional, a Gogny force, and a relativistic mean-field Lagrangian are considered side by side. The crucial role of the treatment of pairing correlations is pointed out in each case. The authors discuss other related nuclear structure models and present several extensions beyond the mean-field model which are currently used. Phenomenological adjustment of the model parameters is discussed in detail. The performance quality of the SCMF model is demonstrated for a broad range of typical applications

  18. A multi-species modelling approach to examine the impact of alternative climate change adaptation strategies on range shifting ability in a fragmented landscape

    OpenAIRE

    Synes, Nicholas W.; Watts, Kevin; Palmer, Stephen C.F.; Bocedi, Greta; Bartoń, Kamil A.; Osborne, Patrick E.; Travis, Justin M.J.

    2015-01-01

    An individual-based model of animal dispersal and population dynamics was used to test the effects of different climate change adaptation strategies on species range shifting ability, namely the improvement of existing habitat, restoration of low quality habitat and creation of new habitat. These strategies were implemented on a landscape typical of fragmentation in the United Kingdom using spatial rules to differentiate between the allocation of strategies adjacent to or away from existing h...

  19. Fuzzy model-based control of a nuclear reactor

    International Nuclear Information System (INIS)

    Van Den Durpel, L.; Ruan, D.

    1994-01-01

    The fuzzy model-based control of a nuclear power reactor is an emerging research topic world-wide. SCK-CEN is dealing with this research in a preliminary stage, including two aspects, namely fuzzy control and fuzzy modelling. The aim is to combine both methodologies in contrast to conventional model-based PID control techniques, and to state advantages of including fuzzy parameters as safety and operator feedback. This paper summarizes the general scheme of this new research project

  20. Simulation model of nuclear power plant turbine

    International Nuclear Information System (INIS)

    Dutta, Anu; Thangamani, I.; Chakraborty, G.; Ghosh, A.K.

    2006-04-01

    A computer code TURDYN has been developed for prediction of HP and LP turbine torque under thermodynamic transient conditions. The model is based on the conservation laws of mass and energy. All the important components of turbine systems e.g. high pressure turbine, low pressure turbine, feed heaters, reheater, moisture separator have been considered. The details of the mathematical formulation of the model and open loop responses for specific disturbances are presented. (author)

  1. A model for nuclear research reactor dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Barati, Ramin, E-mail: Barati.ramin@aut.ac.ir; Setayeshi, Saeed, E-mail: setayesh@aut.ac.ir

    2013-09-15

    Highlights: • A thirty-fourth order model is used to simulate the dynamics of a research reactor. • We consider delayed neutrons fraction as a function of time. • Variable fuel and temperature reactivity coefficients are used. • WIMS, BORGES and CITVAP codes are used for initial condition calculations. • Results are in agreement with experimental data rather than common codes. -- Abstract: In this paper, a useful thirty-fourth order model is presented to simulate the kinetics and dynamics of a research reactor core. The model considers relevant physical phenomena that govern the core such as reactor kinetics, reactivity feedbacks due to coolant and fuel temperatures (Doppler effects) with variable reactivity coefficients, xenon, samarium, boron concentration, fuel burn up and thermal hydraulics. WIMS and CITVAP codes are used to extract neutron cross sections and calculate the initial neuron flux respectively. The purpose is to present a model with results similar to reality as much as possible with reducing common simplifications in reactor modeling to be used in different analyses such as reactor control, functional reliability and safety. The model predictions are qualified by comparing with experimental data, detailed simulations of reactivity insertion transients, and steady state for Tehran research reactor reported in the literature and satisfactory results have been obtained.

  2. Design of nuclear power generation plants adopting model engineering method

    International Nuclear Information System (INIS)

    Waki, Masato

    1983-01-01

    The utilization of model engineering as the method of design has begun about ten years ago in nuclear power generation plants. By this method, the result of design can be confirmed three-dimensionally before actual production, and it is the quick and sure method to meet the various needs in design promptly. The adoption of models aims mainly at the improvement of the quality of design since the high safety is required for nuclear power plants in spite of the complex structure. The layout of nuclear power plants and piping design require the model engineering to arrange rationally enormous quantity of things in a limited period. As the method of model engineering, there are the use of check models and of design models, and recently, the latter method has been mainly taken. The procedure of manufacturing models and engineering is explained. After model engineering has been completed, the model information must be expressed in drawings, and the automation of this process has been attempted by various methods. The computer processing of design is in progress, and its role is explained (CAD system). (Kako, I.)

  3. Infinite nuclear matter model and mass formulae for nuclei

    International Nuclear Information System (INIS)

    Satpathy, L.

    2016-01-01

    The matter composed of the nucleus is a quantum-mechanical interacting many-fermionic system. However, the shell and classical liquid drop have been taken as the two main features of nuclear dynamics, which have guided the evolution of nuclear physics. These two features can be considered as the macroscopic manifestation of the microscopic dynamics of the nucleons at fundamental level. Various mass formulae have been developed based on either of these features over the years, resulting in many ambiguities and uncertainties posing many challenges in this field. Keeping this in view, Infinite Nuclear Matter (INM) model has been developed during last couple of decades with a many-body theoretical foundation employing the celebrated Hugenholtz-Van Hove theorem, quite appropriate for the interacting quantum-mechanical nuclear system. A mass formula called INM mass formula based on this model yields rms deviation of 342 keV being the lowest in literature. Some of the highlights of its result includes its determination of INM density in agreement with the electron scattering data leading to the resolution of the long standing 'r 0 -paradox' it predicts new magic numbers giving rise to new island of stability in the drip-line regions. This is the manifestation of a new phenomenon where shell-effect over comes the repulsive component of nucleon-nucleon force resulting in the broadening of the stability peninsula. Shell quenching in N= 82,and N= 126 shells, and several islands of inversion have been predicted. The model determines the empirical value of the nuclear compression modulus, using high precission 4500 data comprising nuclear masses, neutron and proton separation energies. The talk will give a critical review of the field of mass formula and our understanding of nuclear dynamics as a whole

  4. Using niche-modelling and species-specific cost analyses to determine a multispecies corridor in a fragmented landscape

    Science.gov (United States)

    Zurano, Juan Pablo; Selleski, Nicole; Schneider, Rosio G.

    2017-01-01

    Misiones, Argentina, contains the largest remaining tract of Upper Paraná Atlantic Forest ecoregion; however, ~50% of native forest is unprotected and located in a mosaic of plantations, agriculture, and pastures. Existing protected areas are becoming increasingly isolated due to ongoing habitat modification. These factors, combined with lower than expected regional carnivore densities, emphasize the need to understand the effect of fragmentation on animal movement and connectivity between protected areas. Using detection dogs and genetic analyses of scat, we collected data on jaguars (Panthera onca), pumas (Puma concolor), ocelots (Leopardus pardalis), oncillas (Leopardus tigrinus), and bush dogs (Speothos venaticus) across habitats that varied in vegetation, disturbance, human proximity, and protective status. With MaxEnt we evaluated habitat use, habitat suitability, and potential species richness for the five carnivores across northern-central Misiones, Argentina. Through a multifaceted cost analysis that included unique requirements of each carnivore and varying degrees of overlap among them, we determined the optimal location for primary/secondary corridors that would link the northern-central zones of the Green Corridor in Misiones and identified areas within these corridors needing priority management. A secondary analysis, comparing these multispecies corridors with the jaguar’s unique requirements, demonstrated that this multispecies approach balanced the preferences of all five species and effectively captured areas required by this highly restricted and endangered carnivore. We emphasize the potential importance of expanding beyond a single umbrella or focal species when developing biological corridors that aim to capture the varied ecological requirements of coexisting species and ecological processes across the landscape. Detection dogs and genetic analyses of scat allow data on multiple species to be collected efficiently across multiple habitat

  5. Common modelling approaches for training simulators for nuclear power plants

    International Nuclear Information System (INIS)

    1990-02-01

    Training simulators for nuclear power plant operating staff have gained increasing importance over the last twenty years. One of the recommendations of the 1983 IAEA Specialists' Meeting on Nuclear Power Plant Training Simulators in Helsinki was to organize a Co-ordinated Research Programme (CRP) on some aspects of training simulators. The goal statement was: ''To establish and maintain a common approach to modelling for nuclear training simulators based on defined training requirements''. Before adapting this goal statement, the participants considered many alternatives for defining the common aspects of training simulator models, such as the programming language used, the nature of the simulator computer system, the size of the simulation computers, the scope of simulation. The participants agreed that it was the training requirements that defined the need for a simulator, the scope of models and hence the type of computer complex that was required, the criteria for fidelity and verification, and was therefore the most appropriate basis for the commonality of modelling approaches. It should be noted that the Co-ordinated Research Programme was restricted, for a variety of reasons, to consider only a few aspects of training simulators. This report reflects these limitations, and covers only the topics considered within the scope of the programme. The information in this document is intended as an aid for operating organizations to identify possible modelling approaches for training simulators for nuclear power plants. 33 refs

  6. Three-dimensional modeling of nuclear steam generator

    International Nuclear Information System (INIS)

    Bogdan, Z.; Afgan, N.

    1985-01-01

    In this paper mathematical model for steady-state simulation of thermodynamic and hydraulic behaviour of U-tube nuclear steam generator is described. The model predicts three-dimensional distribution of temperatures, pressures, steam qualities and velocities in the steam generator secondary loop. In this analysis homogeneous two phase flow model is utilized. Foe purpose of the computer implementation of the mathematical model, a special flow distribution code NUGEN was developed. Calculations are performed with the input data and geometrical characteristics related to the D-4 (westinghouse) model of U-tube nuclear steam generator built in Krsko, operating under 100% load conditions. Results are shown in diagrams giving spatial distribution of pertinent variables in the secondary loop. (author)

  7. Relativistic nuclear matter with alternative derivative coupling models

    International Nuclear Information System (INIS)

    Delfino, A.; Coelho, C.T.; Malheiro, M.

    1994-01-01

    Effective Lagrangians involving nucleons coupled to scalar and vector fields are investigated within the framework of relativistic mean-field theory. The study presents the traditional Walecka model and different kinds of scalar derivative coupling suggested by Zimanyi and Moszkowski. The incompressibility (presented in an analytical form), scalar potential, and vector potential at the saturation point of nuclear matter are compared for these models. The real optical potential for the models are calculated and one of the models fits well the experimental curve from-50 to 400 MeV while also gives a soft equation of state. By varying the coupling constants and keeping the saturation point of nuclear matter approximately fixed, only the Walecka model presents a first order phase transition of finite temperature at zero density. (author)

  8. Multiscale Modeling and Uncertainty Quantification for Nuclear Fuel Performance

    Energy Technology Data Exchange (ETDEWEB)

    Estep, Donald [Colorado State Univ., Fort Collins, CO (United States); El-Azab, Anter [Florida State Univ., Tallahassee, FL (United States); Pernice, Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Peterson, John W. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Polyakov, Peter [Univ. of Wyoming, Laramie, WY (United States); Tavener, Simon [Colorado State Univ., Fort Collins, CO (United States); Xiu, Dongbin [Purdue Univ., West Lafayette, IN (United States); Univ. of Utah, Salt Lake City, UT (United States)

    2017-03-23

    In this project, we will address the challenges associated with constructing high fidelity multiscale models of nuclear fuel performance. We (*) propose a novel approach for coupling mesoscale and macroscale models, (*) devise efficient numerical methods for simulating the coupled system, and (*) devise and analyze effective numerical approaches for error and uncertainty quantification for the coupled multiscale system. As an integral part of the project, we will carry out analysis of the effects of upscaling and downscaling, investigate efficient methods for stochastic sensitivity analysis of the individual macroscale and mesoscale models, and carry out a posteriori error analysis for computed results. We will pursue development and implementation of solutions in software used at Idaho National Laboratories on models of interest to the Nuclear Energy Advanced Modeling and Simulation (NEAMS) program.

  9. Application of 3-dimensional CAD modeling system in nuclear plants

    International Nuclear Information System (INIS)

    Suwa, Minoru; Saito, Shunji; Nobuhiro, Minoru

    1990-01-01

    Until now, the preliminary work for mutual components in nuclear plant were readied by using plastic models. Recently with the development of computer graphic techniques, we can display the components on the graphics terminal, better than with use of plastic model and actual plants. The computer model can be handled, both telescopically and microscopically. A computer technique called 3-dimensional CAD modeling system was used as the preliminary work and design system. Through application of this system, database for nuclear plants was completed in arrangement step. The data can be used for piping design, stress analysis, shop production, testing and site construction, in all steps. In addition, the data can be used for various planning works, even after starting operation of plant. This paper describes the outline of the 3-dimensional CAD modeling system. (author)

  10. Nuclear reactor fuel rod behavior modelling and current trends

    International Nuclear Information System (INIS)

    Colak, Ue.

    2001-01-01

    Safety assessment of nuclear reactors is carried out by simulating the events to taking place in nuclear reactors by realistic computer codes. Such codes are developed in a way that each event is represented by differential equations derived based on physical laws. Nuclear fuel is an important barrier against radioactive fission gas release. The release of radioactivity to environment is the main concern and this can be avoided by preserving the integrity of fuel rod. Therefore, safety analyses should cover an assessment of fuel rod behavior with certain extent. In this study, common approaches for fuel behavior modeling are discussed. Methods utilized by widely accepted computer codes are reviewed. Shortcomings of these methods are explained. Current research topics to improve code reliability and problems encountered in fuel rod behavior modeling are presented

  11. The Gogny-Hartree-Fock-Bogoliubov nuclear-mass model

    Energy Technology Data Exchange (ETDEWEB)

    Goriely, S. [Universite Libre de Bruxelles, Institut d' Astronomie et d' Astrophysique, CP-226, Brussels (Belgium); Hilaire, S.; Girod, M.; Peru, S. [CEA, DAM, DIF, Arpajon (France)

    2016-07-15

    We present the Gogny-Hartree-Fock-Bogoliubov model which reproduces nuclear masses with an accuracy comparable with the best mass formulas. In contrast to the Skyrme-HFB nuclear-mass models, an explicit and self-consistent account of all the quadrupole correlation energies is included within the 5D collective Hamiltonian approach. The final rms deviation with respect to the 2353 measured masses is 789 keV in the 2012 atomic mass evaluation. In addition, the D1M Gogny force is shown to predict nuclear and neutron matter properties in agreement with microscopic calculations based on realistic two- and three-body forces. The D1M properties and its predictions of various observables are compared with those of D1S and D1N. (orig.)

  12. Fission fragment mass distributions via prompt γ-ray spectroscopy

    Indian Academy of Sciences (India)

    The distribution of fragment masses formed in nuclear fission is one of the most strik- ing features .... 80. 100. 120. 140. 160. 10. 3. 10. 4. Fragment Mass. Relative yield. Sn. Cd. Te. Pd ... the secondary fragment at Z = 50 and N = 82 shells, where the yields are depleted. Both ... More systematic experimental data are required.

  13. Integrated multi-scale modelling and simulation of nuclear fuels

    International Nuclear Information System (INIS)

    Valot, C.; Bertolus, M.; Masson, R.; Malerba, L.; Rachid, J.; Besmann, T.; Phillpot, S.; Stan, M.

    2015-01-01

    This chapter aims at discussing the objectives, implementation and integration of multi-scale modelling approaches applied to nuclear fuel materials. We will first show why the multi-scale modelling approach is required, due to the nature of the materials and by the phenomena involved under irradiation. We will then present the multiple facets of multi-scale modelling approach, while giving some recommendations with regard to its application. We will also show that multi-scale modelling must be coupled with appropriate multi-scale experiments and characterisation. Finally, we will demonstrate how multi-scale modelling can contribute to solving technology issues. (authors)

  14. Organization model and formalized description of nuclear enterprise information system

    International Nuclear Information System (INIS)

    Yuan Feng; Song Yafeng; Li Xudong

    2012-01-01

    Organization model is one of the most important models of Nuclear Enterprise Information System (NEIS). Scientific and reasonable organization model is the prerequisite that NEIS has robustness and extendibility, and is also the foundation of the integration of heterogeneous system. Firstly, the paper describes the conceptual model of the NEIS on ontology chart, which provides a consistent semantic framework of organization. Then it discusses the relations between the concepts in detail. Finally, it gives the formalized description of the organization model of NEIS based on six-tuple array. (authors)

  15. Modeling issues in nuclear plant fire risk analysis

    International Nuclear Information System (INIS)

    Siu, N.

    1989-01-01

    This paper discusses various issues associated with current models for analyzing the risk due to fires in nuclear power plants. Particular emphasis is placed on the fire growth and suppression models, these being unique to the fire portion of the overall risk analysis. Potentially significant modeling improvements are identified; also discussed are a variety of modeling issues where improvements will help the credibility of the analysis, without necessarily changing the computed risk significantly. The mechanistic modeling of fire initiation is identified as a particularly promising improvement for reducing the uncertainties in the predicted risk. 17 refs., 5 figs. 2 tabs

  16. Nuclear anapole moment and tests of the standard model

    International Nuclear Information System (INIS)

    Flambaum, V. V.

    1999-01-01

    There are two sources of parity nonconservation (PNC) in atoms: the electron-nucleus weak interaction and the magnetic interaction of electrons with the nuclear anapole moment. A nuclear anapole moment has recently been observed. This is the first discovery of an electromagnetic moment violating fundamental symmetries--the anapole moment violates parity and charge-conjugation invariance. We describe the anapole moment and how it can be produced. The anapole moment creates a circular magnetic field inside the nucleus. The interesting point is that measurements of the anapole allow one to study parity violation inside the nucleus through atomic experiments. We use the experimental result for the nuclear anapole moment of 133 Cs to find the strengths of the parity violating proton-nucleus and meson-nucleon forces. Measurements of the weak charge characterizing the strength of the electron-nucleon weak interaction provide tests of the Standard Model and a way of searching for new physics beyond the Standard Model. Atomic experiments give limits on the extra Z-boson, leptoquarks, composite fermions, and radiative corrections produced by particles that are predicted by new theories. The weak charge and nuclear anapole moment can be measured in the same experiment. The weak charge gives the mean value of the PNC effect while the anapole gives the difference of the PNC effects for the different hyperfine components of an electromagnetic transition. The interaction between atomic electrons and the nuclear anapole moment may be called the ''PNC hyperfine interaction.''

  17. Overview of geochemical modeling needs for nuclear waste management

    International Nuclear Information System (INIS)

    Isherwood, D.J.; Wolery, T.J.

    1985-01-01

    Geochemical modeling needs for nuclear waste management are discussed with an emphasis on data base development and computer code. Other areas for future research include: precipitation kinetics, fixed fugacity, sorption, glasslt. slashwater interactions, redox disequilibrium and kinetics, radiolysis, solid solutions, and isotopic fractionation. 15 references

  18. A different interpretation of the nuclear shell model

    International Nuclear Information System (INIS)

    Fabre de la Ripelle, M.

    1984-12-01

    In the first order approximation the nucleons are moving into a collective well extracted from the two-body N-N interaction. The nuclear shell model is explained by the structure of the first order solution of the Schroedinger equation. In the next step the two-body correlations generated by the N-N potential are introduced in the wave function

  19. Statistical properties of the nuclear shell-model Hamiltonian

    International Nuclear Information System (INIS)

    Dias, H.; Hussein, M.S.; Oliveira, N.A. de

    1986-01-01

    The statistical properties of realistic nuclear shell-model Hamiltonian are investigated in sd-shell nuclei. The probability distribution of the basic-vector amplitude is calculated and compared with the Porter-Thomas distribution. Relevance of the results to the calculation of the giant resonance mixing parameter is pointed out. (Author) [pt

  20. EMPIRE-II statistical model code for nuclear reaction calculations

    Energy Technology Data Exchange (ETDEWEB)

    Herman, M [International Atomic Energy Agency, Vienna (Austria)

    2001-12-15

    EMPIRE II is a nuclear reaction code, comprising various nuclear models, and designed for calculations in the broad range of energies and incident particles. A projectile can be any nucleon or Heavy Ion. The energy range starts just above the resonance region, in the case of neutron projectile, and extends up to few hundreds of MeV for Heavy Ion induced reactions. The code accounts for the major nuclear reaction mechanisms, such as optical model (SCATB), Multistep Direct (ORION + TRISTAN), NVWY Multistep Compound, and the full featured Hauser-Feshbach model. Heavy Ion fusion cross section can be calculated within the simplified coupled channels approach (CCFUS). A comprehensive library of input parameters covers nuclear masses, optical model parameters, ground state deformations, discrete levels and decay schemes, level densities, fission barriers (BARFIT), moments of inertia (MOMFIT), and {gamma}-ray strength functions. Effects of the dynamic deformation of a fast rotating nucleus can be taken into account in the calculations. The results can be converted into the ENDF-VI format using the accompanying code EMPEND. The package contains the full EXFOR library of experimental data. Relevant EXFOR entries are automatically retrieved during the calculations. Plots comparing experimental results with the calculated ones can be produced using X4TOC4 and PLOTC4 codes linked to the rest of the system through bash-shell (UNIX) scripts. The graphic user interface written in Tcl/Tk is provided. (author)