Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

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33412 Publications

Nachweis von Bestrahlungsdefekten in WWER-RDB-Stählen durch Kleinwinkelstreuexperimente

Böhmert, J.
  • Lecture (Conference)
    Jahrestagung Kerntechnik 1995
  • Contribution to proceedings
    Proc. Jahrestagung Kerntechnik '95, Nürnberg, Mai 1995, S. 379 - 381

Permalink: https://www.hzdr.de/publications/Publ-267
Publ.-Id: 267


A Note on Thermocapillary Instability in the Presence of a Magnetic Field

Thess, A.; Nitschke, K.
We formulate the asymptotic theory of thermocapillary instability in a planar fluid layer heated from below in the presence of a strong magnetic field corresponding to high Hartmann number. Explicit asymptotic expressions are derived for the velocity perturbation, temperature perturbation and electric current density. Their spatial structure is characterized in terms of Hartmann boundary layers - a concept which permits a physical understanding of more complicated situations involving surface deformation, buoyancy and thermoelectric effects. The physical nature of large scale instabilities in the case of a deformable surface is clarified.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-61

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Permalink: https://www.hzdr.de/publications/Publ-264
Publ.-Id: 264


Tilted Cranking

Frauendorf, S.; Meng, J.; Reif, J.
  • Contribution to external collection
    Int. Sym. on Phys. with large gamma-ray arrays, Berkeley 1994
  • Open Access Logo Forschungszentrum Rossendorf; FZR-59 Preprint

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Permalink: https://www.hzdr.de/publications/Publ-262
Publ.-Id: 262


Three Contributions to the Seventh International Symposium on Small Particles and Inorganic Clusters

Frauendorf, S.; Reimann, S. M.; Pashkevich, V. V.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-58 Preprint

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Permalink: https://www.hzdr.de/publications/Publ-261
Publ.-Id: 261


Resonance phenomena at high level density

Sobeslavsky, E.; Dittes, F.-M.; Rotter, I.
  • Journal of Physics A 28 (1995) pp. 2963
  • Open Access Logo Forschungszentrum Rossendorf; FZR-60 Preprint

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Permalink: https://www.hzdr.de/publications/Publ-260
Publ.-Id: 260


Schaffung eines Internationalen Zentrums für Information und Frühwarnung bei nuklearen Ereignissen in mittel- und osteuropäischen Kernkraftwerken

Carl, H.; Schumann, P.; Zschau, J.
Im Rahmen eines vom Sächsischen Staatsministeriums für Wissenschaft und Kunst geförderten Vorhabens wurden 1994 die Untersuchungen zu den Aufgaben, zu den zu erwartenden Kosten und zu den Realisierungschancen für ein internationales Zentrum für Information und Frühwarnung bei nuklearen Ereignissen in mittel- und osteuropäischen Kernkraftwerken planmäßig fortgesetzt und das laufende Projekt mit dem Abschlußbericht zum 31.12.1994 abgeschlossen.
Für die anstehenden Aufgaben, nämlich Abschätzung der Emissionen, Prognose der Radioaktivitätsausbreitung, Verfolgung der Lageentwicklung und Mitwirkung bei der Vorbereitung von Notfallschutzmaßnahmen sind im wesentlichen radiologische Meßwerte über die freigesetzten radioaktiven Stoffe und meteorologischen Kennwerte zur Beschreibung der Ausbreitungsbedingungen an das Zentrum zu übertragen. Betriebliche Informationen über den Anlagenzustand sind nur im Sinne von Hintergrundinformationen erforderlich, wozu 8 bis 10 ausgewählte sicherheitsrelevante Betriebsparameter ausreichend sind.

Obwohl der Sinn eines solchen Vorhabens außer Frage steht, sind die Realisierungschancen ohne eine umfassende Förderung durch die EG und andere internationale Organisationen - World Association of Nuclear Operators WANO, International Atomic Energy Agency IAEA - gering.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-57

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Permalink: https://www.hzdr.de/publications/Publ-259
Publ.-Id: 259


Bestimmung von Actiniden in Bauschutt, Determination of actinides in concrete

Nebelung, C.; Hübener, S.; Bernhard, G.
  • Poster
    27. Jahrestagung Entsorgung, 25.-29.9.1995 Wolfenbüttel
  • Reihe: Fortschritte im Strahlenschutz; Entsorg. Band II; 27. Jahrestagung Wolfenbüttel, Fachverb. f. Strahlenschutz e. V., FS-95-77-1, ISSN 1013-4506

Permalink: https://www.hzdr.de/publications/Publ-256
Publ.-Id: 256


Aktuelle Ergebnisse der Untersuchungen zum Mechanismus der Neutronen Versprödung in Reaktordruckbehälterstahl

Große, M.; Böhmert, J.; Brauer, G.
Bestrahlungsinduzierte Ausscheidungen gelten als die strukturelle Ursache der Neutronenversprödung von Reaktordruckbehälterstahl (RDB-Stahl). Am Beispiel des WWER-440 RDB-Stahls 15Cr2MFA wird die Korrelation zwischen dem Volumenanteil an bestrahlungsinduzierten Ausscheidungen und der Erhöhung der Sprödbruchübergangstemperatur diskutiert. Es wird eine bimodale Abhängigkeit dieser beiden Größen gefunden. Ursache des bimodalen Verhaltens sind möglicherweise unterschiedliche Arten von bestrahlungsinduzierten Ausscheidungen, die vom Gehalt an Verunreinigungselementen bestimmt sind.
Erste resonante Röntgenkleinwinkelstreuexperimente an Material mit niedrigem Cu-Gehalt zeigen, daß Vanadium ein wesentlicher Bestandteil der bestrahlungsinduzierten Ausscheidungen ist. Die Ergebnisse von Neutronenkleinwinkelstreuung und Positronenannihilationsspektroskopie unterstützen die Hypothese, daß es sich bei den Ausscheidungen im RDB-Stahl 15Cr2MFA um Vanadiumkarbide handelt.
  • Lecture (Conference)
    Seminar GKSS Geesthacht Abt. WN, 1994

Permalink: https://www.hzdr.de/publications/Publ-254
Publ.-Id: 254


The New Rossendorf Nuclear Microprobe

Herrmann, F.; Grambole, D.

The New Rossendorf Nuclear Microprobe1)
F. Herrmann and D. Grambole

Recently a 3 MV tandetron accelerator was put into operation at the Research Center Rossendorf. At this accelerator we have installed a new nuclear microprobe. The object forming aperture can be changed continuously from 0 to 150 µm and in each direction independently. The magnetic quadrupole triplet delivered by Danfysik has an energy mass product of 45 MeV.amu. Magnetic coils placed behind it scan the beam over an area up to 1 x 1 mm². A manipulator with X-Y-Z-translation, 360° rotation, and tilt enables us together with the adequate detectors to apply ERDA, PIXE, RBS, and NRA. A PC based CAMAC system acquires data from four ADCs. Up to four elemental maps with up to 128 x 128 pixels can be displayed on-line. All events are stored together with their coordinates in list mode for further analysis.
A general problem for a quantitative analysis is the accuracy of charge measurement. Using the whole target chamber as a Faraday cup which would be the best method is impossible in our installation. A negatively biased electrode in front of the target for suppressing the secondary electrons cannot be used either. Therefore a precise current integrator was developed which can operate with a positive offset voltage of several hundred volts at the input. The principle of this integrator will be described as well as first experiences and comparisons to other charge measuring methods. Furthermore, a beam monitoring system based on this integrator was set up for an easy control of the beam.

1) The project was supported by Bundesminister für Forschung und Technologie under contract 03-GR3ROS
  • Nuclear Instruments and Methods in Physics Research B 104 (1995) 26-30
  • Lecture (Conference)
    Fourth International Conference on Nuclear Microprobe Technology and Applications Shanghai, China, October 10-14, 1994

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Permalink: https://www.hzdr.de/publications/Publ-252
Publ.-Id: 252


Interplay of Collective Flow Phenomena and Velocity Correlations of Intermediate - Mass Fragments in Collisions of Au+Au at E=100-400 A MeV

Kotte, R.; Kämpfer, B.; Mösner, J.; Neubert, W.; Wohlfarth, D.; u. a.
  • Physical Review C 51 (1995) 2686
  • Open Access Logo Forschungszentrum Rossendorf; FZR-56 Preprint

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Permalink: https://www.hzdr.de/publications/Publ-251
Publ.-Id: 251


Analysis of transients for NPP with VVER-440 using the code SiTAP

Kalinenko, V.
The report contains results of the analysis of the transients "Loop connection" and "SG tube rupture" for NPP with VVER-440 type reactors. To obtain detailled informations about NPP's dynamic characteristics, various variants of initial and boundary conditions are considered.
Calculation of these transients was performed with use of the code SiTAP developed at the Nuclear Safety Institute of Russian Research Centre "Kurchatov Institute". SiTAP is a multi-functional computer tool for fast analysis of transient and accidental processes of VVER type reactors for engineers working in the field of NPP dynamics.
SiTAP can be used for comparative analysis of several variants of accident scenarios to find out the conditions leading to the most severe consequences from safety point of view. For this cases, additional analyses using best-estimate codes should be carried out.
The results from SiTAP for faulty loop connection leading to a boron dilution accident are intended to be used as boundary conditions for a more detailled analysis by the help of the three-dimensional reactor core model DYN3D, developed in the Research Centre Rossendorf for the simulation of reactivity initiated accidents.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-54

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Permalink: https://www.hzdr.de/publications/Publ-250
Publ.-Id: 250


A Note on Bénard Marangoni Instability in the Presence of a Magnetic Field

Thess, A.; Nitschke, K.
Explicit asymptotic expressions are derived for the first unstable mode of surface tension driven instability in an electrically conducting fluid subjected to a strong magnetic field. The spatial structure of the velocity, temperature, and electric current density is characterized in terms of Hartmann boundary layers - a concept that permits a physical explanation of the role of the magnetic field and an understanding of scaling laws derived in previous work.
  • Physics of Fluids 7 (1995) 1176-1178

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Permalink: https://www.hzdr.de/publications/Publ-249
Publ.-Id: 249


Pushing and Cranking Corrections to the Meson Fields of the Bosonized Nambu & Jona-Lasinio Model

Schleif, M.; Wünsch, R.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-55 Preprint

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Permalink: https://www.hzdr.de/publications/Publ-248
Publ.-Id: 248


Wind Energy Ressources in Saxony: An Experimental Approach

Daniels, W.; Kuntzsch, J.; Rindelhardt, U.
In 1991 a special programme was initiated by the Saxonian Environmental Ministry to estimate the wind energy potential in Saxony and to identify sites for economic operation of wind energy converters.
In the frame of the programme 16 wind measuring stations were erected, more concentrated in orographically complicated regions. The wind speed was measured at two heights between 10 m and 36 m a. g. l. Ten-minutes-averaging-values of wind velocity and direction were registrated over a time of minimally one year.
The danish Wind-Atlas Program WASP was applied to calculate wind atlas librariers from the measured wind datas. The atlas library represents the regional wind climate of the measuring station. Because WASP was developed mainly for coast and lowland regions far from mountains, special efforts were necessary to estimate the region of representance in Saxony. It could be shown, that in lowland regions the area of representance regions in some cases was comparable with WASP results from coast regions. Especially in the mountain region of the "Erzgebirge" the representance regions was found to be very small. By means of atlas libraries the wind power density in the northern part of Saxony was calculated.

On the basis of these investigations the wind energy potential of Saxony could be estimated. Totally 500 usable sites were identified with an average number of 5 500-kW-wind turbines at each site. Using these capacity a yearly energy production of 2200 GWh seems to be possible.
  • Lecture (Conference)
    Proceedings of the European Wind Energy Association Conference EWEC'94, 10.-14. Oktober 1994, Thessaloniki, Greece, Volume I, p. 238 - 243
  • Contribution to proceedings
    Proceedings of the European Wind Energy Association Conference EWEC'94, 10.-14. Oktober 1994, Thessaloniki, Greece, Volume I, p. 238 - 243

Permalink: https://www.hzdr.de/publications/Publ-247
Publ.-Id: 247


Amorphization and Recrystallization of 6H-SiC by Ion Beam Irradiation

Heera, V.; Kögler, R.; Skorupa, W.; Stoemenos, J.
  • Journal of Applied Physics 77 (1995) 2999
  • Poster
    Poster und Proceedings bei MRS Spring Meeting 1994, San Francisco, Mat. Res. Soc. Symp. Proc. 339 (1994) 197

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Permalink: https://www.hzdr.de/publications/Publ-246
Publ.-Id: 246


Thermocapillary Bubble Migration at Higher Marangoni numbers - Theory and Experiment

Gerbeth, G.; Galindo, V.; Treuner, M.; Langbein, D.
Single bubble motion driven purely by thermocapillarity (i.e. a linear temperature gradient in the surrounding liquid) is analyzed theoretically with the following steps: A full numerical simulation up to Re of several hundreds depending on the Prandtl-number of the liquid, and a simple analytical treatment describing the asymptotic migration at high Re. Results of short-term microgravity experiments performed at drop Tower Bremen will be reported for 20 < Re < 160. The theoretical migration velocities are slightly higher than the experimental values which might be due to the short-time nature of the experiments. An unsteady theoretical analysis will be given explaining, at least in part, the remaining discrep-ancy between theory and experiment.
  • Lecture (Conference)
    1994 Meeting APS/DFD, Atlanta, 20-22 November
  • Bulltin of the American Physical Society, Series II, 39 (1994), 9, p. 1841

Permalink: https://www.hzdr.de/publications/Publ-245
Publ.-Id: 245


Control of the Cylinder Wake Instabilities by an External Magnetic Field

Mutschke, G.; Gerbeth, G.
The standard cylinder wake is considered for the magnetohydrodynamic (MHD) case: The fluid is electrically conducting and exposed to an external uniform magnetic field of different directions. In general, the magnetic field stabilizes the flow, the vortex street can be suppressed for each Re. A numerical simulation of the time-dependent flow as well as a simple analytical stability analysis will be presented and compared with available and own experiments. The experimentally found tendency of an increasing level of low-frequency perturbations for an increasing magnetic field will be discussed and compared with the analytical stability analysis. Typical features of the MHD case will be presented: Drag increase, up- and downstream wakes, surface pressure redistribution, recirculation bubbles at high Re, etc.
  • Lecture (Conference)
    and Proceedings: 1994 Meetingof the Division of Fluid Dynamics (APS/DFD), Atlanta, 20-22 November 1994, Bulletin of the American Physical Society, Series II, 39 (1994) 9, p. 1979

Permalink: https://www.hzdr.de/publications/Publ-244
Publ.-Id: 244


Photovoltaik in den neuen Bundesländern: Ergebnisse des 1000-Dächer-Programms in Sachsen

Rindelhardt, U.
Die Nutzung der Photovoltaik in den neuen Bundesländern wird am Beispiel Sachsens dargestellt. Der größte Impuls kam vom Bund-Länder-1000-Dächer-Photovoltaik-Programm, das die Installation von kleinen netzgekoppelten PV-Anlagen förderte. Weitere Anwendungen betreffen Nischenmärkte wie z.B. Parkscheinautomaten.
  • Lecture (Conference)
    Deutsch-Russische Konferenz "Erneuerbare Energiequellen in Rußland und Deutschland", Freiburg, 24.-26.10.1994, Tagungsband S. 44
  • Contribution to proceedings
    Deutsch-Russische Konferenz "Erneuerbare Energiequellen in Rußland und Deutschland", Freiburg, 24.-26.10.94, Tagungsband S. 44

Permalink: https://www.hzdr.de/publications/Publ-243
Publ.-Id: 243


"De re metallica" (G. Agricola) - IBA on air

Neelmeijer, C.; Wagner, W.; Schramm, H.-P.; Thiel, U.
On the occasion of Georgius Agricola's 500th birthday in 1994 attention has been focused on the paint material found in an exemplar of his famous scientific book “De re metallica”. The very thin color coatings on the highly sensitive paper substrate represent a challenge to the power and the guaranteed non-destructiveness of IBA. The combined implementation of PIXE and RBS on the external proton beam set-up allows one to determine the chemical elements of the pigments used and to identify the presence of organic layers. Results from selected colors are given to emphasize the complementary character of on-air PIXE-RBS analysis.
Keywords: ion beam analysis, non-destructive analysis, external proton beam, PIXE, RBS, book painting, thin layers
  • Nuclear Instruments and Methods in Physics Research B 99 (1995) 390
  • Lecture (Conference)
    Denton-Conf. 1994

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Permalink: https://www.hzdr.de/publications/Publ-242
Publ.-Id: 242


Slow, highly charged ions from a 7.25 GHz ECR ion source

Henke, D.; Tyrroff, H.; Grötzschel, R.; Wirth, H.
  • Contribution to external collection
    Beitrag zur HCI 1994

Permalink: https://www.hzdr.de/publications/Publ-241
Publ.-Id: 241


Interconnection lines following the surface topography fabricated by writing focused ion beam implantation

Bischoff, L.; Teichert, J.; Hesse, E.
The Rossendorf Focused Ion Beam IMSA-100 was used for writing Co-implantation over a topographical structure surface with a prtly controlled focus. After a subsequent annealing the resulting CoSi2 interconnection lines were analysed by SEM and electrical measurements. Also the influence of the depth of focus on the height of the surface contours as well as the resulting radial beam profiles were investigated.
  • Microelectronic Engineering 27 (1995) pp. 351-354

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Permalink: https://www.hzdr.de/publications/Publ-240
Publ.-Id: 240


Einbindung ins Fernnetz wird in Sachsen erprobt

Brünig, D.; Rindelhardt, U.
Solarwärme - Einbindung ins Fernwärmenetz wird in Sachsen erprobt
Die im Juni 1994 in Betrieb genommene solarthermische Anlage mit 100 m2 Kollektorfläche ist ein sächsisches Modellvorhaben. Neben der üblichen solaren Trinkwarmwasserbereitung - hier für die Schule - steht die Einspeisung von Solarwärme in ein neugeschaffenes gasbeheiztes Fernwärmenetz im Mittelpunkt eines Langzeitmeß- und analyseprogramms des Forschungszentrums Rossendorf. Die Solaranlage arbeitet nach dem Low-Flow-Prinzip der Kollektordurchströmung in Verbindung mit einer selbstregelnden Speicherschichtbeladung. Regelung und Meßdatenerfassung werden durch eine DDC-Anlage realisiert.
  • Sonnenenergie & Wärmetechnik 5/1994, S.21

Permalink: https://www.hzdr.de/publications/Publ-239
Publ.-Id: 239


Shell-model States and Collectivity in83Br48 and 85Rb48

Schwengner, R.; Winter, G.; Reif, J.; Prade, H.; Käubler, L.; Wirowski, R.; Nicolay, N.; Albers, S.; Esser, S.; von Brentano, P.; Andrejtscheff, W.
Excited states of the nuclei 83Br and 85Rb were populated
in the reaction 82Se(7Li,alpha2n) and 82Se(7Li,4n),
respectively, using the 7Li beams of the FN tandem accelerator
in Cologne (E=32 MeV) and of the 120 cm cyclotron in Rossendorf (E=35 MeV).Gamma-gamma-particle
coincidences were measured with six Ge and fourteen Si detectors installed
at the detector array Cologne OSIRIS CUBE. This technique enabled a reaction
channel selection. Multipole orders of the gamma-rays were derived from
directional correlations of coincident gamma-rays and from angular distributions.
Mean lifetimes were deduced for seven levels in 83Br and two
levels in 85Rb using the Doppler-shift-attenuation method. The
level scheme of 83Br has been extended up to (21+/2)
and 15-/2 states. In 85Rb a level sequence built
on the ground state has been established up to 15(-)/2 and a
new cascade of fast M1 transitions starting with a 17(-)/2 state
at 3198.2 keV has been found. Furthermore, several medium-spin states have
been newly introduced. The level sequences inboth nuclei have been interpreted
in terms of the shell model. The calculations performed in the model space
pi(0g9/2, 1p1/2, 1p3/2, 0f5/2)
v(0g9/2, 1p1/2) reproduce single-particle characteristics
as well as collective properties of the level sequences.
  • Physica Scripta T56 (1995) pp. 126

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Permalink: https://www.hzdr.de/publications/Publ-238
Publ.-Id: 238


Neutron-Core Excitations in 3686Kr50

Reif, J.; Winter, G.; Schwengner, R.; Prade, H.; Grawe, H.; Schubart, R.
Shell-model calculations for the N=50 nucleus 86Kr are presented
and compared toresults of recent in-beam experiments. Two model spaces
are considered: a pure proton configuration space containing the 0f5/2,
1p3/2, 1p1/2, 0g9/2 orbitals and a model
space including additionally the particlehole  excitation generated
by one neutron lifted from the 0g9/2 orbital across the shell
gap to the 1d5/2 orbital. The predictions of the shell-model
using various sets of residual interactions and based on pure proton excitations
are comparable with the experimental findings for the states of positive
parity below 4 MeV and for the negative-parity states with spins up to
7-. The inclusion of neutron-core excitations causes an improved
agreement between experimental and calculated level energies for the positive-parity
yrast states with spins 7, 9 and 10. The interpretation of neutron-core
excited high-spin states is supported by the comparision of the level structure
of 3686Kr50 to the experimental levels
of the valence-mirror nucleus 2864Ni36.
  • Physica Scripta T56 (1995) pp. 303

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Permalink: https://www.hzdr.de/publications/Publ-237
Publ.-Id: 237


Enzymatic cleavage of Technetium and Rhenium complexes with DMSA ester ligands

Seifert, S.; Syhre, R.; Spies, H.; Johannsen, B.
  • Lecture (Conference)
    Technetium and Rhenium in Chemistry and Nuclear Medicine, Edited by Nicolini, M.; Bandoli, G. and Mazzi, U., SGEDITORIALI Padovo 4 (1995) 437-440
  • Contribution to external collection
    Technetium and Rhenium in Chemistry and Nuclear Medicine, Edited by Nicolini, M.; Bandoli, G. and Mazzi, U., SGEDITORIALI Padovo 4 (1995) 437-440

Permalink: https://www.hzdr.de/publications/Publ-236
Publ.-Id: 236


Technetium and Rhenium Complexes with Multidentale Thioether Ligands

Pietzsch, H.-J.; Spies, H.; Leibnitz, P.; Reck, G.; Johannsen, B.
  • Poster
    4th Intern. Sympos. on Tc in Chemistry and Nuclear Medicine, Brixen, in: Technetium and Rhenium in Chemistry and Nuclear Medicine, Edited by Nicolini, M.u.a., SGEDITORIALI Padova 4 (1995) 231-234
  • Contribution to external collection
    4th Intern. Sympos. on Tc in Chemistry and Nuclear Medicine, Brixen, in: Technetium and Rhenium in Chemistry and Nuclear Medicine, Edited by Nicolini, M.u.a., SGEDITORIALI Padova 4 (1995) 231-234

Permalink: https://www.hzdr.de/publications/Publ-235
Publ.-Id: 235


The n+1 -concept in the synthesic strategy of novel technetium and rhenium tracers

Spies, H.; Fietz, T.; Glaser, M.; Pietzsch, H.-J.; Johannsen, B.
  • Contribution to external collection
    Technotium and rhenium in chemistry and nuclear medicine, Edited by Nicolini, M.; Bandoli, G, and Mazzi, U., SGEDITORIALI Padova 4 (1995) 243-246

Permalink: https://www.hzdr.de/publications/Publ-234
Publ.-Id: 234


Tc - complexes of N- alkylated Mercaptoacetyl glycines as potential Tracers for imaging atherosclerotic lesions

Noll, B.; Noll, S.; Spies, H.; Johannsen, B.; Dinkelborg, L.; Semmler, W.
  • Poster
    Technetium and Rhenium in Chemistry and Nuclear Medicine, Edited by Nicolini, M.; Bandoli, G. and Mazzi, U., SGEDITORIALI, Padova 4 (1995) 433-436
  • Contribution to external collection
    Technetium and Rhenium in Chemistry and Nuclear Medicine, Edited by Nicolini, M.; Bandoli, G. and Mazzi, U., SGEDITORIALI, Padova 4 (1995) 433-436

Permalink: https://www.hzdr.de/publications/Publ-233
Publ.-Id: 233


Synthesis and characterization of isocyanide containing rhenium(III) complexes trans-[ReCl3(CNR)(PPh3)2] and crystal structure of trans-[ReCl3(CN-t-C4H9)(PPh3)2]

Spies, H.; Glaser, M.; Hahn, F. E.; Lügger, T.; Scheller, D.
  • Inorganica Chimica Acta 232 (1995) 235-239

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Permalink: https://www.hzdr.de/publications/Publ-232
Publ.-Id: 232


Tilted four -quasiparticle bands in even-even Xe-and Ba-nuclei

Dönau, F.; Frauendorf, S.; Vogel, O.; Gelberg, A.; von Brentano, P.
  • Nuclear Physics A 584 (1995) pp. 241

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Permalink: https://www.hzdr.de/publications/Publ-231
Publ.-Id: 231


Coupling of the Thermohydraulic Code ATHLET with the Neutron Kinetic Core Model DYN3D

Grundmann, U.; Lucas, D.; Rohde, U.
The coupling of advanced thermohydraulic codes with 3-dimensional neutron kinetic codes corresponds to the effort to replace conservative estimations by best estimate calculations. ATHLET is an advanced thermohydraulic code, developed by the German Gesellschaft fr Anlagen- und Reaktorsicherheit (GRS). Up to now only point kinetics and 1-dimensional neutron kinetics have been included. The DYN3D code, developed in the Research Centre Rossendorf (RCR) for the improvement of the simulation of reactivity initiated accidents in nuclear reactors with hexagonal fuel elements comprises 3-dimensional neutron kinetics, models for the thermohydraulics of the core including heat transfer from the fuel to the coolant and a fuel rod behavior model.

The reactor core model DYN3D was coupled with the ATHLET code on two basically different ways. The first way of coupling uses only the neutron kinetics part of the DYN3D code (internal coupling). This coupling along the core is very close and demands an high effort of programming due to the high number of coupling parameters.

In the second way the whole core is cut out from the ATHLET plant model. The core is completly modeled by the DYN3D code (external coupling). In this case the interfaces are located at the bottom and at the top of the core. At this interfaces the pressures, mass flow rates, enthalpies and concentrations of boron acid have to be transferred. This way of coupling is easy to realize by interconnection of an interface routine. It is effectively supported by the General Control and Simulation Modul (GCSM) of the ATHLET code. Almost no changes of the single programs are necessary. Another advantage of this coupling is that the complete DYN3D model can be used.

The disadvantage of this method is the splitting of the thermohydraulics. A closed implicit time integration of the whole system of thermohydraulic equations like in the ATHLET code would demand strong changes of the single programs o ...
  • Lecture (Conference)
    Int. Conf. on Mathematics and Computations, Reactor Physics and Environmental Analysis, April 30. - May 5., 1995, Portland, Oregon, USA, Proc., Vol. 1, pp. 257 - 263
  • Contribution to external collection
    Int. Conf. on Mathematics and Computations, Reactor Physics and Environmental Analysis, April 30. - May 5., 1995, Portland, Oregon, USA, Proc., Vol. 1, pp. 257 - 263

Permalink: https://www.hzdr.de/publications/Publ-230
Publ.-Id: 230


Thermocapillary convection in a liquid metal under influence of the magnetic field - experimental techniques and results of the tests

Gerbeth, G.; Bojarevics, A.; Gelfgat, Y. M.
Thermocapillary convection in low-Prandtl-number fluids up to now remains insufficiently studied experimentally due to difficulties to realize free surface conditions on liquid metals. A novel technique has been developed to produce small sized easily transportable deep vacuum container filled with a thin layer of gallium under a transparent glass window. The first tests showed that the free surface of the liquid gallium did not deteriorate during a period of up to 45 days. The flow pattern on the free surface, while point heating the bottom of the container, has been demonstrated. The temperature gradient on the free surface of the liquid gallium caused surface relief deformations of an order up to 10 - 100 microns. Video recordings of the tracer particle motion on the free surface of liquid gallium due to thermal convection and surface relief deformations due to changes in heating conditions has been made. The presence of the thermocapillary convection has been demonstrated.
  • Lecture (Conference)
    Konferenz "Energy Transfer in MHO Flows", Aussois / France, Sept.1994, pp. 117 - 126
  • Contribution to proceedings
    Konferenz "Energy Transfer in MHO Flows", Aussois / France, Sept.1994, pp. 117 - 126

Permalink: https://www.hzdr.de/publications/Publ-229
Publ.-Id: 229


A Conditioning Method for the Safe Disposal of Highly Radioactive Unstable Carbon-14-Labelled Organic Compounds

Heise, K.-H.; Bubner, M.; Nitsche, H.; Förster, E.
  • Lecture (Conference)
    Fifth International Conference on Radioactive Waste Management and Environmental Remediation, Berlin 1995

Permalink: https://www.hzdr.de/publications/Publ-228
Publ.-Id: 228


Einspeisung von Solarwärme in konventionelle Fern- und Nahwärmenetze

Brünig, D.; Naehring, F.; Rindelhardt, U.
In der Arbeit werden unterschiedliche Konzepte der Einbindung großer Solaranlagen in konventionelle Wärmesysteme untersucht. Am Beispiel der Solaranlagen in Oederan und Freital wird die dezentrale Einbindung und die Einkopplung in Fernwärmenetze mit den entsprechenden Vor- und Nachteilen diskutiert. Als entscheidender Parameter für den zu erwartenden Ertrag erweist sich das Temperaturniveau des aufnehmenden Netzes.
  • Energieanwendung, Energie- und Umwelttechnik 43 (1994), 445

Permalink: https://www.hzdr.de/publications/Publ-227
Publ.-Id: 227


Thermocapillary bubble migration -Drop tower experiments-

Galindo, V.; Gerbeth, G.; Treuner, M.; Langbein, D.; Rath, H. J.
Experiments on the thermocapillary bubble migration are presently carried out in the Drop Tower Bremen. After a heating period of about two hours, a sufficiently linear temperature gradient is established with paraffin liquids in a cavity. For the moment of drop of the capsule two bubbles with diameters of up to 2 mm are generated and the injection needles are retracted. During 4.74 s under strongly reduced gravity the speed of the bubble migration is observed with video camera, the temperature field by Pt 100 temperature gauges and the use of a differential interferometer. First experimental results with a liquid characterized by the Prandtl number Pr = 10 (n-decane) agree very well with theoretical data available both from literature as well as with numerical simulations. The correspoding Reynolds numbers are in the range between 20 < Re < 160. The experimental setup, the measuring technique and the evaluation method will be presented as well as comparison between experimental and theoretical results.
  • Lecture (Conference)
    "Drop Tower Days 94", Bremen, Juli 1994

Permalink: https://www.hzdr.de/publications/Publ-226
Publ.-Id: 226


External proton beam analysis of layered objects

Wagner, W.; Neelmeijer, C.
Ion-beam analysis for determining the elemental composition and to obtain depth information has been carried out with MeV protons in air by means of simultaneous external PIXE and RBS. Stainless steel products of extended size and a historic painting are analysed non-destructively. These objects include systems of layers with area densities up to some mg/cm2. Depth information is obtained by PIXE using energy variation of the primary proton beam and in addition directly from RBS for the outermost near-surface region. Main and secondary elements as well as impurities can be determined together with area densities. Particularly, the knowledge on the depth distribution of the pigments in paintings provides information on paint techniques.
Keywords: ion beam analysis, PIXE, RBS, external proton beam,layers, non-destructive analysis, art objects, near-surface analysis
  • Fresenius J. Anal. Chem. 353 (1995) 297

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Publ.-Id: 225


Dekontaminationsuntersuchungen an Bauteilen der radiochemischen Anlage AMOR-I

Friedrich, H.; Bernhard, G.
  • Poster
    GDCh - Fachtagung 5.-7.9.1994

Permalink: https://www.hzdr.de/publications/Publ-224
Publ.-Id: 224


Analysis of Art Objects by the Combined Application of three Ion Beam Methods on Air

Neelmeijer, C.; Wagner, W.; Schramm, H.-P.
The simultaneous combination of PIXE, RBS and PIGE at the external proton beam is presented as a useful tool for non-destructive studies on a variety of art objects, i.e. oil paintings, book paintings and historical glasses.
Keywords: ion beam analysis, external proton beam, non-destructive analysis, PIXE, PIGE, RBS, art objects
  • Contribution to external collection
    4th International Conf. on Non-Destructive Testing of Works of Art (1994) p. 296

Permalink: https://www.hzdr.de/publications/Publ-223
Publ.-Id: 223


A Retarding Field Energy Analyser to measure the Energy Distributions of Liquid Metal Ion Sources

Stins, O. W. M.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-53

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Permalink: https://www.hzdr.de/publications/Publ-222
Publ.-Id: 222


Bericht der Frühjahrstagung der Studiengruppe Elektronische Instrumentierung vom 21. bis 23. März 1994 in Berlin

Gabriel, F.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-48

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Publ.-Id: 221


Verifikation des 3-dimensionalen Kernmodells DYN3D/M2

Grundmann, U.; Rohde, U.
Es wird eine Übersicht über die wesentlichsten Ergebnisse bisheriger Arbeiten zur Verifikation des dreidimensionalen Kernmodells DYN3D/M2 für Reaktoren mit hexagonalen Brennelementen gegeben. Verifikationsuntersuchungen für stationäre und instationäre Leistungsdichteberechnung, Thermohydraulik und Brennstabmodell sowie das Gesamtmodell werden beschrieben. Die Verifikation erfolgte durch Nachrechnung von Einzeleffekttests und Experimenten an WWER-spezifischen Versuchsanlagen, Vergleich mit anderen Codes und Benchmarklösungen sowie teilweise durch Vergleich berechneter Parameter mit Betriebsmeßdaten aus KKW mit WWER. Verifikationsbedarf besteht insbesondere noch für das Gesamtmodell und die Anwendung auf den WWER-1000.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-47

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Publ.-Id: 220


Institute of Radiochemistry; Annual Report 1993

Nitsche, H.; Bernhard, G.; Engelmann, H.-J.; Geipel, G.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-43

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Permalink: https://www.hzdr.de/publications/Publ-219
Publ.-Id: 219


Paint layer studies using PIXE and RBS on air

Wagner, W.; Neelmeijer, C.; Schramm, H.-P.
To identify layer structures of oil paintings and to determine their elemental composition, external beam PIXE and in addition external beam RBS have been applied simultaneously. The beam energy is varied to obtain depth information by means of PIXE. To check the evidence of the idea a set of test paint layers is prepared. It is found that a combination of the two ion-beam analysis techniques delivers the information needed. The pigment components of the test layers are detected and attached to the layers and additionally the layer thickness is determinable. As an example measurements on the historical painting "14 Nothelfer" (L. Cranach the elder) are presented which are gained by means of external PIXE at various proton energies coupled with external beam RBS.
Keywords: ion beam analysis, external proton beam, non-destructive avalysis, paint layers, PIXE, RBS
  • Contribution to external collection
    4th Int. Conf. on Non-destructive Testing of Works of Art (1994) p. 316

Permalink: https://www.hzdr.de/publications/Publ-217
Publ.-Id: 217


Fluenzberechnungen für das Bestrahlungsprogramm Rheinsberg von Materialproben im Rheinsberger Reaktor im Zeitraum 1984-1988

Barz, H.-U.; Konheiser, J.
Im Zeitraum von 1984 - 1988 wurde am Rheinsberger Reaktor ein umfangreiches Bestrahlungsprogramm für Stahlproben aus verschiedenen Druckbehältermaterialien durchgeführt. Zielstellung des Vorhabens ist die Ermittlung der Veränderung der bruchmechanische Eigenschaften durch den Einfluß der Neutronenstrahlung.
Ein Teilaspekt für diese Zielstellung ist die Bestimmung der Parameter für die Neutronenbelastung. In diesem Bericht werden das methodische Vorgehen zur Gewinnung dieser Werte beschrieben, mögliche Fehlerquellen diskutiert sowie ein umfangreicher Überblick über die Ergebnisse gegeben.
Grundlage der transporttheoretischen Berechnungen bei gegebenen Spaltquellen war die Vielgruppen-Monte-Carlo-Methode mit speziellen Verfahren zur Minimierung der statistischen Fehler, so daß Ergebnisse mit kleinem statistischen Fehler für jede Einzelprobe, die im allgemeinen noch in vertikaler bzw. horizontaler Richtung unterteilt wurde, erzielt werden konnten.
Zur Berechnung der Spaltquelle wurde die für ein Zeitraster für jedes Kassettenelement gegebenen Abbranddaten zugrunde gelegt, auf deren Basis für jeder Reaktorbetriebsperiode die integralen Spaltquellverteilungen für verschiedene Spaltisotope berechnet wurden.
Dargestelt werden die für die Neutronenversprödung relevanten Ergebnisse, nämlich die kumulativen Neutronenflüsse im Energiebereich größer 0,5 und 1 MeV sowie eine dpa-Rate. Als allgemeines Resultat kann man die starke Abhängigkeit der Ergebnisse in radialer Richtung vom Reaktormittelpunkt anführen. Dagegen ergaben sich in azimulater und vertikaler Richtung nur relativ schwache Veränderungen.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-51 August 1994

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Permalink: https://www.hzdr.de/publications/Publ-216
Publ.-Id: 216


Characterization of Irradiation-induced Precipitates by Small Angle X-ray and Neutron Scattering Experiments Effects of Radiation on Materials

Große, M.; Böhmert, J.; Eichhorn, F.; Brauer, G.
The nature of the irradiation-induced precipitates in the VVER-440-type steel 15Kh2MFA has been investigated by the combination of small angle neutron scattering and anomalous small angle X-ray scattering. By the method of contrast variation information about the chemical composition of the irradiation-induced precipitates was obtained. ASAXS experiments with variation of the X-ray energy near to the energy of the vanadium K-absorption edge prove the content of vanadium within the irradiation-induced precipitates. The scattering density of the precipitates is lower than the scattering density of the iron matrix. The chemical shift of the vanadium-K -absorption-edge and the results of the variation of the contribution of the magnetic scattering in the SANS experiment show, that vanadium does not precipitate in an elementary state. By assuming the precipitates being vanadium carbide these results can be explained in the best way.
  • Lecture (Conference)
    17th Volume, ASTM STP 1270, D.S. Gelles, R.K. Nanstadt, A.S. Kumar, E.A. Little, Eds., American Society for Testing and Materials, Philadelphia, p. 1123
  • Contribution to external collection
    17th Volume, ASTM STP 1270, D.S. Gelles, R.K. Nanstadt, A.S. Kumar, E.A. Little, Eds., American Society for Testing and Materials, Philadelphia, p. 1123

Permalink: https://www.hzdr.de/publications/Publ-214
Publ.-Id: 214


ASAXS and SANS Investigations of the Chemical Composition of Irradiation-induced Precipitates in Nuclear Pressure Vessel Steels

Große, M.; Böhmert, J.; Eichhorn, F.; Brauer, G.; Haubold, H.-G.; Goerigk, G.
The deterioration of the mechanical properties of reactor pressure vessel (RPV) steels during their irradiation in a nuclear power plant is known as neutron embrittlement. The structural reason of the neutron embrittlement of low alloyed RPV steel is the radiation-induced formation of precipitates. Up to now the chemical composition of these precipitates in the VVER 440 type RPV steel 15Kh2MFA are not clarified.
A combination of small angle neutron scattering (SANS) and small angle X-ray scattering (SAXS) using methods of contrast variation were employed to determine the chemical composition of the irradiation-induced precipitates in the 15Kh2MFA steel.
The difference between the scattering intensities from irradiated and unirradiated specimens gives the small angle scattering effect of the radiation damages. Irradiation-induced precipitates were found with a mean diameter of = 1...2 nm. The defect volume fraction is depending on the neutron fluence and amounts 0.1 - 0.35 %.
Information about the chemical composition was obtained by using the magnetic scattering contrast in the SANS experiment and the anomalous scattering contrast in the SAXS measurements.
A scan of the X-ray energy in the range of the V-, Cr-, Mn-, and Fe-K-absorption edges proves that the precipitates are vanadium rich. The scattering density of the precipitates is lower than the scattering density of the matrix.
This facts and the results of the magnetic contrast variation in the SANS experiments are in agreement with the assumption that the irradiation-induced precipitates are vanadium carbides.
  • Nuclear Instruments and Methods in Physics Research B97 (1995), 487 - 490

Permalink: https://www.hzdr.de/publications/Publ-213
Publ.-Id: 213


A novel setup for spectroscopic ellipsometry using an acousto-optic tuneable filter

Fukarek, W.; von Keudell, A.
  • Review of Scientific Instruments 66 (1995) 6, pp. 3545-3550 (zum Patent angemeldet am 20.12.93)

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Permalink: https://www.hzdr.de/publications/Publ-211
Publ.-Id: 211


Particle excitations and collectivity in the N=48 nuclei 83Br and 85Rb

Schwengner, R.; Winter, G.; Reif, J.; Prade, H.; Käubler, L.; Wirowski, R.; Nicolay, N.; Albers, S.; Esser, S.; von Brentano, P.; Andrejtscheff, W.
Excited states of the nuclei 83Br and 85Rb were populated
in the reaction 82Se(7Li,alpha2n) and 82Se(7Li,4n),
respectively, using the 7Li beams of the FN tandem accelerator
in Cologne (E=32 MeV) and of the 120 cm cyclotron in Rossendorf (E=35 MeV).Gamma-gamma-particle
coincidences were measured with six Ge and fourteen Si detectors installed
at the detector array Cologne OSIRIS CUBE. This technique enabled a reaction
channel selection. Multipole orders of the gamma-rays were derived from
directional correlations of coincident gamma-rays and from angular distributions.
Mean lifetimes were deduced for seven levels in 83Br and two
levels in 85Rb using the Doppler-shift-attenuation method. The
level scheme of 83Br has been extended up to (21+/2)
and 15-/2 states. In 85Rb a level sequence built
on the ground state has been established up to 15(-)/2 and a
new cascade of fast M1 transitions starting with a 17(-)/2 state
at 3198.2 keV has been found. Furthermore, several medium-spin states have
been newly introduced. The level sequences inboth nuclei have been interpreted
in terms of the shell model. The calculations performed in the model space
pi(0g9/2, 1p1/2, 1p3/2, 0f5/2)
v(0g9/2, 1p1/2) reproduce single-particle characteristics
as well as collective properties of the level sequences.
  • Nuclear Physics A 584 (1995) pp. 159

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Permalink: https://www.hzdr.de/publications/Publ-209
Publ.-Id: 209


Evaluation of Radioselenium Labeled Selenomethionine, a Potential Tracer for Brain Protein Synthesis by PET

Bergmann, R.; Brust, P.; Kampf, G.; Coenen, H. H.; Stöcklin, G.
  • J. Nucl. Med. Biol. 22 (1995) 475-481

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Publ.-Id: 207


Reverse Currents of p+/n diodes after High Energy Implantation of C+ and Ge+ ions and Annealing

Kögler, R.; von Borany, J.; Panknin, D.; Skorupa, W.; Baither, D.
  • Nuclear Instruments and Methods in Physics Research B 96 (1995) 814
  • Lecture (Conference)
    IIT 94

Permalink: https://www.hzdr.de/publications/Publ-206
Publ.-Id: 206


Technetium- and Rhenium Complexes with Thioether Ligands-IV. Synthesis and Structural Characterization of Binuclear Oxorhenium (V) Complexes with Bidentate Thioether Coordination

Pietzsch, H.-J.; Spies, H.; Leibnitz, P.; Reck, G.
  • Polyhedron 14 (1995) 13-14 pp.1849-1853

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Publ.-Id: 205


A New Method for Acoustic Leak Detection at Complicated Geometrical Structures

Hessel, G.; Schmitt, W.; Weiß, F.-P.
A method for detecting and localizing leaks at complicated three-dimensional topologies by measuring the leak induced structure-borne and airborne sound and by applying pattern recognition procedures is being developed. The sound patterns necessary to train fuzzy logic classifiers and neural networks are generated with simulated leaks at the original structure. As features for characterizing the occurrence and the location of a leak, coherence values between high-frequency microphone signals and RMS-values of acoustic emission sensors are used. The method is even applicable when localization based on propagation time differences or sound attenuation differences fail. The method is prototypically developed for a soviet-type pressurized VVER-reactor.
  • Contribution to proceedings
    IFAC Symposium on Fault Detection, Supervision and Safety for Technical Processes SAFEPROCESS'94, June 13-16, 1994, Helsinki, Finland, Vol. 1, pp. 153 - 158

Permalink: https://www.hzdr.de/publications/Publ-204
Publ.-Id: 204


Functionalization of Technetium Complexes to Make Them Active in Vivo

Spies, H.; Johannsen, B.
  • The Analyst, 120 (1995)

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Publ.-Id: 203


Component Vibration of VVER-reactors -Diagnostics and modelling-

Altstadt, E.; Liewers, P.; Scheffler, M.; Schumann, P.; Weiß, F.-P.
Flow induced vibrations of reactor pressure vessel (RPV) internals (control element and core barrel motions) at VVER-440 reactors have lead to the development of dedicated methods for on-line monitoring. These methods need a certain developed stage of the faults to be detected. To achieve a real sensitive early detection of mechanical faults of RPV internals, a theoretical vibration model was developed based on finite elements. The model comprises the whole primary circuit including the steam generators (SG). By means of that model all eigenfrequencies up to 30 Hz and the corresponding mode shapes were calculated for the normal vibration behaviour. Moreover the shift of eigenfrequencies and of amplitudes due to the degradation or to the failure of internal clamping and spring elements could be investigated, showing that a recognition of such degradations even inside the RPV is possible by pure excore vibration measurements. A true diagnostics, that is the identification of the failed component, might become possible because different faults influence different and well separated eigenfrequencies.
  • Progress in Nuclear Energy, Vol. 29, Number 3/4, pp. 129 - 138
  • Lecture (Conference)
    IMORN-25, 13.-15. Juni 1994

Permalink: https://www.hzdr.de/publications/Publ-202
Publ.-Id: 202


Rapidity dependence of thermal dileptons resulting from hadronizing quark-gluon matter with finite baryon charge

Kämpfer, B.; Pavlenko, O. P.; Gorenstein, M. I.; Peshier, A.; Soff, G.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-50 Preprint
  • Zeitschrift für Physik A 353 (1995) pp. 71

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Publ.-Id: 201


Nodales Modell zur Berechnung der Neutronenflußdichteschwankungen infolge stochastischer Schwingungen von Regelelementen mit hexagonalem Querschnitt

Hollstein, F.
Auf der Basis eines dreidimensionalen nodalen Geometriemodells für den WWER-440-Reaktor mit Nodes in Hexagonal-z-Geometrie werden die Beziehungen zur iterativen Berechnung der mittleren Neutronenflußdichte in einer Node sowie deren Schwankungen infolge stochastischer Regelelementschwingungen dargestellt.

Für die Rauschquellenmodellierung werden entsprechend der Konstruktion eines Regelelementes als räumliches Doppelpendel mit Absorber- und Brennstoffteil zwei verschiedene geometrische und neutronenphysikalische Ansätze verwendet.
Das durch Schwingungen der Brennstoffteile verursachte Neutronenflußrauschen wird auf Flächenquellen zurückgeführt. Die Flächenquellen werden dabei durch Materialparameterschwankungen infolge der Regelelementverlagerung innerhalb des Führungskanals induziert.
Für den Absorberteil wird das Modell des "thermisch schwarz" absorbierenden Hohlzylinders auf Körper mit hexagonalem Querschnitt übertragen.
Beide Rauschquellen werden als Störungen der über die Nodeoberflächenteile gemittelten partiellen Neutronenstromdichten in der Zweigruppendiffusionsnäherung beschrieben.
Die Übertragung der Rauschsignale wird in der Prompt-Response-Approximation behandelt. Die Kopplung von "Zweigruppen-Quell-Nodes" mit "Eingruppen-Übertragungs-Nodes" wird auf der Basis der modifizierten Eingruppendiffusionsnäherung realisiert.
Die dargestellten Algorithmen sind Grundlage für die Entwicklung eines Rechenpgrogramms zur Untersuchung der ortsabhängigen Übertragungsfunktionen von Neutronenflußdichteschwankungen mit stochastischen Regelelementschwingungen als Rauschquelle.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-52

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Publ.-Id: 200


An new effective model of the quark-gluon plasma with thermal parton masses

Peshier, A.; Kämpfer, B.; Pavlenko, O. P.; Soff, G.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-49 Preprint
  • Book (Authorship)
    "Hot Hadronic Matter: Theory and experiment", NATO ASI series B, 346 (1995) pp. 139
  • Physics Letters B 337 (1994) pp. 235

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Permalink: https://www.hzdr.de/publications/Publ-199
Publ.-Id: 199


Aufbau eines technischen Systems zur Verbesserung der betrieblichen Überwachung der KKW durch die staatlichen Aufsichtsbehörden (Saporoshje)

Beyer, M.; Carl, H.; Langer, L.; Schumann, P.; Seidel, A.; Zschau, J.; Nowak, K.; Tolksdorf, P.
Es wird ein techisches System zur Verbesserung der betrieblichen Überwachung eines WWER-1000-Reaktorblockes im KKW Saporoshje vorgestellt, das die Aufsichtsbehörde in die Lage versetzen soll, diesen Block unabhängig vom Betreiber zu beaufsichtigen, seinen Sicherheitszustand zu beurteilen und durch Auflagen zu beeinflussen. Das System gestattet auf Grund moderner Ausrüstung eine frühzeitige Meldung von Störungen aller Art und der damit verbundenen Aktivitätsfreisetzungen. Es stellt eine Grundlage für die Frühwarnung der Öffentlichkeit in Gefahrensituationen sowie für eine effektive Einleitung von Notfallschutzmaßnahmen dar. Dazu werden 49 betriebliche Parameter vom Reaktorblock, 18 block- und analgenspezifische radiologische und 6 meteorologische Meßgrößen überwacht. Die geschätzten Kosten für die Realisierung einer Minimalvariante (ohne Baumaßnahmen und Installationsaufwand) belaufen sich auf ca. 1,3 Mio. DM, zuzüglich 650 TDM für notwendige Ertüchtigungen der Meßtechnik. Der Anschluß eines weiteren WWER-1000-Blockes verursacht entsprechende Kosten von etwa 200 TDM.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-44: Kurzfassung (nicht zur Veröffentl. freigeg.)
  • Open Access Logo Forschungszentrum Rossendorf; FZR-45: Anlage A: Textteil (nicht zur Veröffentl. freigeg.)

Permalink: https://www.hzdr.de/publications/Publ-198
Publ.-Id: 198


Unified description of quasi-free and resonant processes of hypernuclear production and decay

Wünsch, R.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-92-03, March 1992

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Permalink: https://www.hzdr.de/publications/Publ-197
Publ.-Id: 197


Description of an open quantum mechanical system

Rotter, I.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-42 Preprint

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Permalink: https://www.hzdr.de/publications/Publ-196
Publ.-Id: 196


Writing implantation with a high current Focused Ion Beam to form CoSi2 - Microstructures

Bischoff, L.; Teichert, J.; Hesse, E.; Panknin, D.; Skorupa, W.
  • Lecture (Conference)
    EIPB '94, New Orleans, 31.5.-3.6.1994

Permalink: https://www.hzdr.de/publications/Publ-195
Publ.-Id: 195


ASAXS and SANS investigations of the chemical composition of irradiation-induced precipitates in nuclear pressure vessel steels

Große, M.; Böhmert, J.; Eichhorn, F.; Brauer, G.; Haubold, H.-G.; Goerigk, G.
  • Poster
    1st European Conference on Synchrotron Radiation in Material Science, Chester UK, 2.-8.7.1994

Permalink: https://www.hzdr.de/publications/Publ-194
Publ.-Id: 194


Recherche zu Gruppendatenbibliotheken für die Anwendung des Programmes DYN3D auf Reaktoren vom Typ WWER

Mittag, S.
Für die Berechnung des Reaktorverhaltens mit Kernmodellen (wie DYN3D) werden sog. Weniggruppen-Neutronendaten benötigt. Es wird eine Übersicht zu entsprechenden Datenbibliotheken für die Spaltzonen von russischen WWER-Reaktoren aufgestellt. Die Informationen über verwendete Primärdaten und die Genauigkeit der Zellcodes für die Gruppendatengenerierung werden im wesentlichen in Tabellenform gegeben. Zur Beurteilung der Qualität der Daten werden Vergleiche zwischen gemessenen und berechneten Reaktorparametern zusammengestellt. Die verfügbaren Informationen ergeben keine signifikanten Qualitätsunterschiede zwischen den einzelnen Datenbibliotheken.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-46

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Permalink: https://www.hzdr.de/publications/Publ-193
Publ.-Id: 193


Thermocapillary bubble migration in a drop tower experiment

Treuner, M.; Langbein, D.; Galindo, V.; Gerbeth, G.
  • Lecture (Conference)
    und Proceedings: 45th IAF Congress, Jerusalem, 9.-14.10.1994

Permalink: https://www.hzdr.de/publications/Publ-192
Publ.-Id: 192


Synthesis and molecular structure of chlore(3-thiapentane-1.5-dithiolato)oxorhenium(V)

Fietz, T.; Spies, H.; Pietzsch, H.-J.; Leibnitz, P.
  • Inorganica Chimica Acta 231 (1995) pp. 233-236

Permalink: https://www.hzdr.de/publications/Publ-191
Publ.-Id: 191


Buried (fe 2-x Co x) Si2 layers with variable band gap formed in silicon by ion beam synthesis (IBS)

Panknin, D.; Wieser, E.; Skorupa, W.; Henrion, W.; Lange, H.
  • Journal of Applied Physics A 62 (1996), 155

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Permalink: https://www.hzdr.de/publications/Publ-190
Publ.-Id: 190


Ermittlung dynamischer Rißeinleitungszähigkeiten mit dem instrumentierten Kerbschlagbiegeversuch bei elastisch-plastischem Werkstoffverhalten

Richter, H.; Viehrig, H.-W.; Winkler, S.
Rißwiderstandskurven sind zum unentbehrlichen Instrumentarium zur Beschreibung des Versagens rißbehafteter Komponenten bei elastisch-plastischem Werkstoffverhalten geworden. Die Abhängigkeit der R-Kurve von der Dicke der jeweiligen Proben gestattet aber nur bedingt die Übertragung der Versuchsergebnisse auf das Bauteilverhalten. In der Literatur wird gezeigt, daß der Beginn der stabilen Rißeinleitung einen echten, geometrieunabhängigen Werkstoffkennwert darstellt. Als anerkannte Methode zur Bestimmung kritischer Rißeinleitungsparameter wird die Messung der Stretchzonenbreite vor der Rißspitze (SZW) verwendet. In quasistatischen Einproben (EPT)- oder in Mehrprobentechniken (MPT) lassen sich mit Hilfe von kritschen SZW gültige Rißeinleitungszähigkeiten auf J-Integralbasis bestimmen.
Noch ungelöst ist das Problem der Ermittlung von dynamischen Rißeinleitungszähigkeiten in EPT mit Hilfe des instrumentierten Kerbschlagbiegeversuches. Hierfür muß durch Messung physikalischer Größen, die mit dem Rißeinleitungsprozeß in Verbindung stehen, der Zeitpunkt der Rißeinleitung detektiert werden. Derartige physikalische Detektionsverfahren sind beispielsweise akustische Emission, elektrische und magnetische Emission. Man erkennt, daß alle drei Verfahren nur indirekt auf Rißbildungsprozesse reagieren. Erste Experimente mit einer Instrumentierung des Kerbschlagbiegeversuchs werden vorgestellt, wobei neben der Schlagkraft gleichzeitig akustische, magnetische und elektrische Emission erfaßt werden.
Durch die simultane Erfassung der Signale verschiedener Methoden in Zusammenhang mit hochauflösender Meßtechnik und mathematisch-numerischen Verfahren der Signalauswertung kann erwartet werden, daß die charakteristischen Zeitpunkte für Rißeinleitung und stabilen Rißfortschritt zuverlässig detektiert werden können.
  • Contribution to proceedings
    Tagungsband der 26. Vortragsveranstaltung des DVM-AK "Bruchvorgänge", Magdeburg, 22. - 23. Februar 1994, S. 373 - 383

Permalink: https://www.hzdr.de/publications/Publ-189
Publ.-Id: 189


Effects of flow on intermediate mass fragments in central gold on gold collisions

Heide, B.; Barz, H.-W.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-41 Preprint
  • Physics Letters B 337 (1994) pp. 53
  • Physics Letters B 340 (1994) pp. 267 (Erratum)

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Publ.-Id: 188


Institute of Nuclear and Hadron Physics; Annual Report 1993

Dönau, F.; Prade, H.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-35

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Permalink: https://www.hzdr.de/publications/Publ-187
Publ.-Id: 187


Institute of Bioinorganic and Radiopharmaceutical Chemistry; Annual Report 1993

Johannsen, B.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-32

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Permalink: https://www.hzdr.de/publications/Publ-186
Publ.-Id: 186


N.C.A. 11C-labelling of aromatic compounds in the ring-position: synthesis of nitro-[1-11C]benzene and [1-11C]aniline

Steinbach, J.; Mäding, P.; Füchtner, F.; Johannsen, B.
  • Journal of Labelled Compounds and Radiopharmaceuticals 36 (1994) 1 pp. 33

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Publ.-Id: 185


High Specific Activity 17alpha-Cyanomethyl-17ß-hydroky-[14alpha, 15alpha-3H]estra-4,9-dien-3-one

Droescher, P.; Römer, J.
  • Journal of Labelled Compounds and Radiopharmaceuticals 36 (1995) 2, pp. 111-119

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Permalink: https://www.hzdr.de/publications/Publ-184
Publ.-Id: 184


Radial pattern of nuclear decay processes

Iskra, W.; Müller, M.; Rotter, I.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-39 Preprint
  • Physical Review C 51 (1995) pp. 1842

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Permalink: https://www.hzdr.de/publications/Publ-182
Publ.-Id: 182


Photovoltaik - Beispielhafte Anlagen in Sachsen

Rindelhardt, U.
Aufgrund verschiedener Förderprogramme des Bundes bzw. des Freistaates Sachsen wurden bis Mai 1994 in Sachsen netzgekoppelte Photovoltaikanlagen mit einer Leistung von insgesamt 400 kWp errichtet. Im Vortrag wird hauptsächlich auf die Ergebnisse der Anlagen eingegangen, die im Rahmen des Bund-Länder-1000-Dächer-Photovoltaik-Programmes errichtet wurden. Weiterhin werden die 40-kWp-Anlage zur Versorgung der Kirnitzschtalbahn (Sächsische Schweiz) und die mit amorphen Si-Modulen ausgerüstete 7,5-kWp-Anlage im SOS-Kinderdorf Zwickau vorgestellt.
  • Lecture (Conference)
    Konferenz "Erneuerbare Energien in Sachsen" des Forums für Zukunftsenergien, Chemnitz, 1.6.1994

Permalink: https://www.hzdr.de/publications/Publ-181
Publ.-Id: 181


Kaon Polarization in Nuclear Matter

Kolomeitsev, E. E.; Voskresensky, D. N.; Kämpfer, B.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-40 Preprint
  • Nuclear Physics A 588 (1995) pp. 889

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Publ.-Id: 180


Solar betriebene netzunabhängige Meßstation - Energiebilanzen eines einjährigen Betriebes

Futterschneider, H.; Rindelhardt, U.; Morgenstern, H.
Für die dosimetrische Umgebungsüberwachung des Forschungsstandortes Rossendorf wurden zwei solar betriebene netzunabhängige Meßsysteme konzipiert und in einem einjährigen Meßzyklus erprobt. Eine wesentliche Forderung bestand in der Gewährleistung einer 100%igen Versorgungssicherheit der Meßsonden.
Die energetisch relevanten Ergebnisse dieser Langzeiterprobung werden diskutiert. Zur Analyse der Energiebilanzen wurden die 10-Minuten-Mittelwerte von Mudolstrom ,und -spannung, Batteriestrom und -spannung, der jeweilige Laststrom und die solare Einstrahlung gemessen. Beide Systeme liefen auch im sehr einstrah- lungsarmen Winter 1993/94 ohne Ausfall. Die vollständige Jahresbilanz des Systems 1 ergab einen reinen Solarbetrieb während 3022 h, einen Batteriebetrieb während 4686 h und in der restlichen Zeit einen Mischbetrieb.
Die gewählte Dimensionierung der beiden photovoltaischen Energieversorgungssysteme erwies sich als ausreichend für einen sicheren Betrieb, die der Auslegung zugrunde liegenden Parameter (spezifische Modulgröße 33 - 41 Wp/W, spezifische Batteriegröße 33 d) können für Systeme mit beliebig großen Lasten verallgemeinert werden.
  • Lecture (Conference)
    9. Internationales Sonnenforum, Stuttgart, 28.6.-1.7.1994, Tagungsbaricht S. 1243 - 1250
  • Contribution to proceedings
    9. Internationales Sonnenforum, Stuttgart, 28.6.-1.7.1994, Tagungsbaricht S. 1243 - 1250

Permalink: https://www.hzdr.de/publications/Publ-179
Publ.-Id: 179


ZERO-POINT Energy Corrected Solitonic Configurations of the Semibosonized NAMBU & JONA-LASINIO Model

Wünsch, R.; Schleif, M.
  • Lecture (Conference)
    Int. Conf. on "Mesons and Nuclei", Dubna, May 1994, World Scientific Publishing Co

Permalink: https://www.hzdr.de/publications/Publ-178
Publ.-Id: 178


Double-grid avalanche counters with large dynamic range

Seidel, W.; u. a.
  • Book (Authorship)
    Fa. ALTIUM, USA, Buch über P-CAD

Permalink: https://www.hzdr.de/publications/Publ-177
Publ.-Id: 177


Solare Brauchwasserbereitung und Einspeisung solarer Überschüsse in den Fernwärmerücklauf

Brünig, D.; Naehring, F.; Rindelhardt, U.
In der Stadt Freital wird ein Modellvorhaben zur Integration solarer Warmwasserbereitung in ein neu geschaffenes Fernwärmesystem auf Erdgasbasis realisiert. Das Projekt beinhaltet den Bau einer solarthermischen Anlage mit einer Kollektorfläche von 100 m² auf einer Schule und deren Einbindung in die im Keller der Schule errichtete Heizzentrale für das umliegende Wohngebiet. Mittels eines umfangreichen Meßprogramms werden die Ergebnisse erfaßt und analysiert.
  • Poster
    Viertes Symposium Thermische Solarenergie, Staffelstein, 9.-10.6.1994, Tagungsband S. 241
  • Contribution to proceedings
    Viertes Symposium Thermische Solarenergie, Staffelstein, 9.-10.6.1994, Tagungsband S. 241

Permalink: https://www.hzdr.de/publications/Publ-176
Publ.-Id: 176


Particle identification in a wide dynamic range based on pulse-shape analysis with solid-state detectors

Pausch, G.; Bohne, W.; Hilscher, D.; Ortlepp, H.-G.; Polster, D.
  • Nuclear Instruments and Methods in Physics Research A 349 (1994) 2/3 pp. 281-284
  • Open Access Logo Forschungszentrum Rossendorf; FZR-38

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Publ.-Id: 175


General Axial Shapes of Sodium Clusters

Frauendorf, S.; Pashkevich, V. V.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-37 Preprint
  • Annals of Physics 5 (1996) pp. 34-56

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Permalink: https://www.hzdr.de/publications/Publ-174
Publ.-Id: 174


Institute of Ion Beam Physics and Materials Research; Annual Report 1993

Möller, W.; Wieser, E.; Kirch, S.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-36

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Publ.-Id: 173


Detailed Monitoring Results and Operating Experiences from 200 Grid Connected Photovoltaic Systems in Germany

Jahn, U.; Grochowski, J.; Decker, B.; Rindelhardt, U.; Teichmann, G.
The German 1000 Roofs Programme includes more than 2000 grid connected photovoltaic (PV) plants, which are being supported by the Federal Ministry for Research and Technology and the governments of the Federal States. Monitoring data, which are continuously produced from the installed PV plants, are now availabe. This paper presents some recent monitored performance data from 250 installed PV systems in Saxony and Lower Saxony together with operating experiences gathered from technical inspections of the projects.
  • Lecture (Conference)
    Proceedings of the 12th European Photovoltaic Solar Energy Conference and Exhibition, Amsterdam, 11-15 April, 1994, Volume I, p. 919 - 922
  • Contribution to proceedings
    Proceedings of the 12th European Photovoltaic Solar Energy Conference and Exhibition, Amsterdam, 11-15 April, 1994, Volume I, p. 919 - 922

Permalink: https://www.hzdr.de/publications/Publ-171
Publ.-Id: 171


Dielectron production in pp and pd collisions at 1-5 GeV

Titov, A. I.; Kämpfer, B.; Bratkovskaya, E. L.
  • Physical Review C 51 (1995) pp. 227
  • Open Access Logo Forschungszentrum Rossendorf; FZR-34 Preprint

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Permalink: https://www.hzdr.de/publications/Publ-169
Publ.-Id: 169


Relaxation of Radiation Damages

Schmidt, B.; Eremin, V.; Ivanov, A.; Strokan, N.; Verbitskaya, E.; Li, Z.
The behavior of radiation-induced carbon-related defects in high-resistivity silicon detectors has been investigated. The defects were introduced by alpha-praticle irradiation and investigated by deep-level transient spectroscopy. An unusual defect behavior consists in low-temperature anealing, including self-annealing at room temperatur, of the interstitial carbon Ci with a simultaneous increase of the Ci-Oi-complex concentration. The kinetic parameters of the process have been determined from the increase of the Ci-center concentration versus time. Two annealing velocities have been observed, which arise from different heat treatments during the detector fabrication process.
  • Journal of Applied Physics 76 (7),1994, 4072-4076

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Publ.-Id: 168


Electromagnetic detection of nonconducting inclusions in a liquid metal flow

Gerbeth, G.; Block, F. R.; Dittmer, R.
The paper describes a first experimental test of a new electromagnetically based bubble detection method in an electrically conducting fluid. A reliable and contin-uous bubble detection method is important for a lot of liquid metal flows, in particular, flows of reactive liquid metals like sodium or lithium. Moreover, the method is suitable for the detection of any inhomogeneity having different electrical conductivity compared to the bulk flow.
The experimental approach for the detection of inhomogeneities was developed at RWTH Aachen for an early slag detection in steel production. The method is based on the fact that a primary electromagnetic field is changed by the motion of an electrically conducting fluid. This change is very sensitive to any inhomogeneities in the flow which have a different electrical conductivity compared to that of the fluid. The signals of suitably arranged secondary coils are evaluated in order to separate the influence of the inhomogeneity. In the experiments performed at the sodium facility of RCR we were able to detect single bubbles which were of diameters in the range 0.5 - 2 mm.
Compared to usual, mainly acoustically based detection methods the following advantages of the electromagnetic approach are obvious:
- No time delay between bubble occurence in the coil region and the signal.
- High sensitivity up to single bubble detection.
- Contactless method. No need to install sensors at hot walls, even a thermal isolation between the coils and the channel is possible.
- Every flowing bubble is detected whereas acoustic methods are able to detect acoustically active bubbles only.
The results of our experiment show convincingly the efficiency of such an electromagnetic detection method.
  • Lecture (Conference)
    "Electromagnetic Proceeding of Materials", Okt. 94, Nagoya, Japan und als Publ. bei ISIJ Japan

Permalink: https://www.hzdr.de/publications/Publ-167
Publ.-Id: 167


Theoretical Aspects of Thermocapillary Convection in Liquid Metals under Magnetic Fields Influence

Priede, J.; Gerbeth, G.; Thess, A.
Magnetic fields provide the possibility to influence the convective flow pattern in an predefined contactless way, in particular, to suppress and control oscillatory instabilities. Therefore, there is increasing interest now in the use of magnetic fields in a variety of materials processing technologies like crystal growth from the melt or directional solidification.
Available knowledge is very limited on the influence of a steady magnetic field (described by the Hartmann number Ha) on convective motions, described by the Grashoff number Gr (buoyancy), and by the Marangoni number Ma (thermocapillarity at free surfaces) in low Prandtl number fluids like liquid metals. Therefore, in the present paper we present theoretical results on the prototype problem of an infinitely extended fluid layer heated either from the side or from the bottom, and exposed to a steady external magnetic field.
In the first part we consider the stability of a unidirectional thermocapillary flow set up by a temperature gradient parallel to the free surface. The magnetic field is supposed to be parallel to the free surface. In this case the magnetic field has no influence on the basic flow, the stability of which is well known without magnetic field. The restriction to disturbances propagating in the same direction as the magnetic field allows to obtain an analytical solution of the stability problem and an explicit expression for the dispersion relation. The hydrothermal wave instability is suppressed by the magnetic field, the critical Marangoni number grows proportionally to Ha. The most unstable wave pattern is stretched along the field lines. The wave number of the most unstable mode decreases as Ha-4/5 for Ha >> 1.
The second part of this communication is devoted to the analysis of the thermocapillary instability in a layer with both temperature gradient and magnetic field being perpendicular to the free surface. Although this problem has been extensively treated in the past, the ...
  • Lecture (Conference)
    "Electromagnetic Processing of Materials", Okt. 94, Nagoya, Japan und als Publ. bei ISIJ Japan

Permalink: https://www.hzdr.de/publications/Publ-166
Publ.-Id: 166


Hydrothermal Wave Instability of Thermocapillary Driven Convection in a Plane Layer Subjected to a Uniform Magnetic Field

Priede, J.; Gerbeth, G.
Thermocapillary driven motion is considered in a horizontal electrically conducting fluid layer heated from the side and exposed to a magnetic field coplanar to the layer. The hydrothermal wave instability and its control by the magnetic field is studied by a linear stability analysis. The special assumption of disturbances traveling crosswise the basic flow allows an analytical solution of the problem. For a particular class of perturbations considered here, the critical Marangoni number and the wavelength of the most unstable mode increase directly with the strength of the applied magnetic field.
  • Advances in Space Research, Vol. 16, No. 7, pp. 55 - 58, Pergamon Press, 1995
  • Lecture (Conference)
    "30th COSPAR Scientific Assembly", Juli 94, Hamburg

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Publ.-Id: 165


Anisotropic transport in MHD turbulence: Experimental results using small gas bubbles as local tracers

Eckert, S.; Gerbeth, G.; Witke, W.; Langenbrunner, H.
It is well known now that in a liquid metal duct flow exposed to a strong transverse magnetic field turbulent fluctuations can persist even when the mean flow can be regarded as laminar with respect to the overall pressure drop. It was also found, that these fluctuations can even be increased under distinct conditions. This effect is in line with the model of two-dimensional MHD turbulence. While 3D turbulence elements are effectively damped by the magnetic field, 2D eddies with axes in the direction of the B-field are not influenced by this damping mechanism. The use of this 2D turbulence allows an enhancement of the heat/mass transport perpendicular to the flow direction without a significant influence on the overall pressure drop.
There is an ongoing research in the FZR MHD group on local transport phenomena in a turbulent LM duct flow exposed to a transverse magnetic field. Measurements were performed at the FZR sodium facility. The advantage of sodium is that high MHD parameters (Ha = 3000, N = 800) can be reached with moderate values of the magnetic field (B = 0.5 T). On the other hand the properties of sodium cause considerable difficulties with respect to any local measurements in such a flow (velocity, fluctuation intensities). Thus the idea was created to use small gas bubbles (argon) as local tracers for the investigation of local transport mechanisms. In the case of our experimental conditions a volumetric gas flow ratio lower than 0.09 clearly indicates a pure bubbly flow regime. The bubbles are injected by means of a single injector in the center of the channel cross section or in the vicinity of a channel wall. The injector was located in the region where the flow enters into the magnetic field. A traversing mechanism allows to move the B-field-region. Single wire resistivity probes are used for measuring the local void fraction and the number of bubbles.
The measured local dispersion of bubbles shows a significant anisotropy which clearly corre ...
  • Lecture (Conference)
    Proceedings of the Second International Conference on ENERGY TRANSFER IN MAGNETOHYDRODYNAMIC FLOWS, Aussois, France, September 26-30, 1994, pp. 787 - 799
  • Contribution to proceedings
    Proceedings of the Second International Conference on ENERGY TRANSFER IN MAGNETOHYDRODYNAMIC FLOWS, Aussois, France, September 26-30, 1994, pp. 787 - 799

Permalink: https://www.hzdr.de/publications/Publ-164
Publ.-Id: 164


Thermocapillary Instabilities in Liquid Metals: Hartmann Number Versus Prandtl-Number

Priede, J.; Gerbeth, G.; Thess, A.
The technical need for instability postponement, turbulence suppression and flow control in material processing as well as the seek for low-cost alternatives to space-technologies for crystal growth are currently leading to an increased interest in the interaction between thermocapillary flows in electrically conducting fluids and magnetic fields. While the interplay between isothermal flows and magnetic fields is well understood, our physical understanding of the influence of magnetic fields on thermocapillary flow phenomena, i.e. flows driven by surface tension gradients, leaves still much to be desired.
The goal of the püresent communication is to demonstrate that a magnetic field acting on the thermocapillary flow of a low Prandtl number fluid causes the fluid to behave like a high Prandtl number fluid. This important feature is exemplified by considering the linear stability of a unidirectional thermocapillary flow set up by a temperature gradient parallel to the free surface of an unbounded planar fluid layer. The magnetic field is supposed to be normal to the free surface. Our problem is the magnetic counterpart to the work of Smith & Davis. We report results of a comprehensive study of the critical Marangoni number for the onset of hydrothermal waves as a function of the Hartmann number and of the Prandtl number. For weak magnetic field the instability mechanism in liquid metals is found to be the same as in the nonmagnetic case for low Prandtl numbers. For sufficiently strong magnetic field the basic flow and the most unstable perturbation are confined to a thin Hartmann boundary layer below the free surface which leads to a decrease of the effective viscous diffusion time-scale as Ha-2. Our Computations reveal that at a certain value of the Hartmann number, when the effective viscous time equals the thermal diffusion time, the character of the instability changes discontinously. The new type of instability is reminiscent of the instability mechanism w ...
  • Magnetohydrodynamics, Proc. Energy Transfer in MHD Flows, Conference, Aussois, France, Sept. 1994, pp. 571 - 580
  • Lecture (Conference)
    "Energy Transfer in MHD Flows", Sept. 1994, Aussois, Frankreich, pp. 571 - 580
  • Contribution to external collection
    "Energy Transfer in MHD Flows", Sept. 1994, Aussois, Frankreich, pp. 571 - 580

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Publ.-Id: 163


Numerical simulation of the two-dimensional MHD flow around a circular cylinder

Shatrov, V.; Mutschke, G.; Gerbeth, G.
In the present paper the time-dependent, two-dimensional, incompressible MHD flow around a circular cylinder is investigated numerically using a finite difference method in stream function-vorticity formulation. The calculations are restricted to the typical situation of liquid metal flows under laboratory conditions where the magnetic Reynolds number is small. The flow is investigated in the parameter range of Re < 10000 and magnetic interaction parameter N < 20 (N = Ha²/Re).
To validate the numerical method, a comparison with the few published numerical results (MOCHIMARU, TSINOBER) is performed, and a good agreement is found. Furthermore, the influence of different outer boundary conditions is tested.
The two cases of a magnetic field aligned to the flow as well as perpendicular to it are investigated in detail. The influence of the magnetic forces on the flow is shown in stream function and vorticity isoline plots for different Reynolds numbers and interaction parameters. The vorticity and pressure distribution at the cylinder surface and the induced magnetic field are calculated and compared with experimental results. The occurrence of a large, but slow recirculation eddy behind the cylinder for a strong aligned magnetic field is discussed. The motion of the fluid becomes more and more stagnant in that region for increasing magnetic fields.
The downstream wake is characterized by the velocity profiles, and the farfield of the vorticity is discussed.
As expected, the influence of the magnetic field on the flow in general is a stabilizing one. In particular, the suppression of an instationary wake flow can be achieved by the magnetic forces. A stability line in the (Re,N)-plane is extracted from the numerical simulations. This result will be compared with a linear stability analysis based on a Galerkin approach.
  • Magnitnaya gidrodinamika 1997 Vol. 33, No. 1, p. 3-13 (in Russian)
  • Lecture (Conference)
    "Energy Transfer in MHD Flows", Sept. 1994, Aussois, Frankreich, pp. 745 - 756
  • Contribution to external collection
    "Energy Transfer in MHD Flows", Sept. 1994, Aussois, Frankreich, pp. 745 - 756

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Publ.-Id: 162


Influence of external magnetic fields on slip ratio in LMMHD two-phase flow

Eckert, S.; Gerbeth, G.; Mihalache, G.; Thibault, J.-P.
LMMHD two-phase flow modelling strongly depends on the accuracy of the constitutive equations and the corresponding closure laws. Several questions rise from various attempts to model these flows. They are mainly connected with the modification of two-phase flow (interfacial dragging, wall friction, apparent elec- trical conductivity, etc.) due to the electromagnetic forces.
The present paper presents a comprehensive survey of the LMMHD two-phase investigations performed in our two laboratories using different liquid systems, mercury-air (LEGI-IMG) and sodium-argon (FZR), with quite different properties. The remarkable difference in the material properties allow us to reach a wide range of nondimensional parameters.
For theoretical predictions a two fluid model (LEGI-IMG) and a bubbly flow model (FZR) have been developed in order to meet the requirements of the corresponding facilities.
The experiments have been realized in rectangular vertical test sections immersed into a transverse magnetic field. The gas is injected in the entrance region of the magnetic field. The distribution of the local void fraction across the channel cross section was measured by means of single wire resistivity probes. The electrical boundary conditions of the test sections are rather different. While the FZR test section consists of a simple stainless steel channel (thickness of the walls: 5 mm), the LEGI-IMG configuration, which includes segmented copper electrodes and an external load resistance, is more similar to a MHD generator. In the FZR experiment a volumetric quality in the range of 0.06 - 0.09 leads to a pure bubbly flow regime. In contrast to this the LEGI-IMG facility usually work with considerable higher gas flow rates.
We present experimental results showing the dependence of the mean values of the void fraction, the slip ratio and the gas velocity on the magnetic field strength as well as on the mean sodium velocity. These results will be compared with the theoreti ...
  • Poster
    "Energy Transfer in MHD Flows", Sept. 1994, Aussois, Frankreich, pp. 607 - 616
  • Contribution to external collection
    "Energy Transfer in MHD Flows", Sept. 1994, Aussois, Frankreich, pp. 607 - 616

Permalink: https://www.hzdr.de/publications/Publ-161
Publ.-Id: 161


On Stability of MHD flow around a cylinder in an aligned magnetic fields

Weier, T.; Mutschke, G.; Gerbeth, G.; Alemany, A.; Pilaud, A.
The hydromagnetic stability of the flow of an incompressible conducting fluid around a circular cyliner in a uniform magnetic field parallel to the mean flow is investigated with different approaches:
Experiments for 1000 < Re < 9000
a simple analytical model
numerical simulation for Re < 1000.
Main goal of the investigations is to find the stability curce inthe (Re, N)-plane, and to distinguish between 2D and 3D instabilities.
Experimental results will be presented based on hot-wire measurements in the down-stream cylinder wake. The suppression of the vortex street by increasing magnetic fields is clearly identified.
Parallel to the disappearance of the typical Kármán frequency an increase of low frequency fluctuations is observed in the spectrum. This will be discussed in therms of theoretical predictions for long-wave MHD instabilities.
More physical insight into the stability behaviour is obtained by a simple Kolmogorov flow modelling of the cylinder wake and the corresponding stability analysis. Theoretical results will be presented for the 2D case: critical Reynolds number, wave number and Strouhal number as function of the magnetic field.
The critical wave number jumbs form the region of the typical Kármán value to very low values at a distinct magnetic field strength. The simple model is extended to include 3D instabilities in the flow. Limitations of the model and the comparison to experiments will be discussed.
Finally the 2D case for Re < 1000 will be compared with results of a full numerical simulation.
  • Magnitnaya gidrodinamika 1997 Vol. 33, No. 1, p. 14-22 (in Russian)
  • Lecture (Conference)
    "Energy Transfer in MHD Flows", Sept. 1994, Aussois, Frankreich

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Permalink: https://www.hzdr.de/publications/Publ-160
Publ.-Id: 160


Unsteady Thermocapillary Drop Migration in a Uniform Temperature Gradient

Galindo, V.; Gerbeth, G.; Langbein, D.; Treuner, M.
A theoretical analysis of liquid drop unsteady migration under microgravity conditions is presented, if an interfracial tension gradient is generated on the drop surface by a uniform temperature gradient in the surrounding liquid. The effect of buoyancy due to a residual gravity vector aligned parallel to the temperature gradient is included. The relevant equations are solved in the creeping flow limit where in the convective transport of momentum as well as that of the energy is neglected, i.e. at low Reynolds and Marangoni numbers. The flow and the temperature field within and around the drop are obtained after transforming the results from the Laplace transform domain, in which they are derived, to the time domain. The time transient behaviour of the Migration speed depends strongly on the choice of the initial flow and temperature fields. The comparison with other initial conditions from the literature is performed.
  • Lecture (Conference)
    "Drop Tower Days 94", Bremen, Juli 1994
  • Contribution to external collection
    Proc. "Drop Tower Days 94", Bremen, Juli 1994, pp. 90 - 94

Permalink: https://www.hzdr.de/publications/Publ-159
Publ.-Id: 159


Some proposals for Marangoni experiments with a pre-prepared temperature gradient

Gerbeth, G.
A serious disadvantage of a lot of microgravity experiments on Marangoni convection is often times the fact that most of the valuable time under microgravity is lost for preparing the necessary temperature gradient. Therefore, the paper will discuss two possibilities of short-term marangoni experiments where the temperature gradient over a plane fluid layer can be prepared in advance, but keeps the fluid motionless.
At first, a convective motion will be started simply by switching off gravity which can result in long-wave surface capillary waves. Such a motion due to surface deformations is suppressed under earth conditions.
Second, various types of Marangoni motions will be discussed for liquid metals exposed to an external magnetic field. Instability thresholds are increased by the magnetic field, i.e. the liquid can be kept motionless by means of the magnetic field under a given temperature gradient.
The paper will discuss the feasibility of such investigations in drop tower experiments.
  • Lecture (Conference)
    "Drop Tower Days 94", Bremen, Juli 1994

Permalink: https://www.hzdr.de/publications/Publ-158
Publ.-Id: 158


Transportreaktionen der Elemente der 6. Gruppe im O2-H2O(g)/SiO2(s)-System

Roß, A.; Hübener, S.; Eichler, B.
  • Lecture (Conference)
    Vortragstagung Fachgruppe Nuklearchemie der GDCh, 5.-7.9.1994

Permalink: https://www.hzdr.de/publications/Publ-156
Publ.-Id: 156


Modellexperimente zur physikochemischen Charakterisierung des Elements 106 als Oxid

Hübener, S.; Roß, A.; Funke, H.
  • Poster
    Vortragstagung der Fachgruppe Nuklearchemie der GDCh

Permalink: https://www.hzdr.de/publications/Publ-155
Publ.-Id: 155


Zur Bestimmung von Actiniden in Bauschutt

Hübener, S.; Nebelung, C.; Bernhard, G.
  • Poster
    Vortragstagung der GDCh-Fachgruppe Nuklearchemie 05.09.-07.09.1994, Berlin

Permalink: https://www.hzdr.de/publications/Publ-154
Publ.-Id: 154


Dekontaminationsuntersuchungen an Bauteilen der Anlage "AMOR-I"

Friedrich, H.; Bernhard, G.; Boeßert, W.
  • Poster
    Vortragstagung der GDCh-Fachgruppe Nuklearchemie

Permalink: https://www.hzdr.de/publications/Publ-153
Publ.-Id: 153


Elektroanalytische IN-SITU-Verfolgung von Schwermetallretentions- und Auslaugungsprozessen an Gesteinsmaterial

Thieme, M.; Geipel, G.; Bernhard, G.; Nitsche, H.
  • Poster
    Analytica Conference 1994, 4/94

Permalink: https://www.hzdr.de/publications/Publ-152
Publ.-Id: 152


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