Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

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34138 Publications

Numerische und experimentelle Untersuchungen zum Schwingungsverhalten eines Siedewasserreaktors

Altstadt, E.; Scheffler, M.; Weiß, F.-P.; Runkel, J.; Südmersen, U.

  • Contribution to proceedings
    Jahrestagung Kerntechnik '97, Aachen, 13. - 15. Mai 1997, Tagungsbericht S.437

Permalink: https://www.hzdr.de/publications/Publ-1606
Publ.-Id: 1606


Dwell-time effects in focused ion beam synthesis of cobalt disilicide: reflectivity measurements

Hausmann, S.; Bischoff, L.; Voelskow, M.; Teichert, J.; Möller, W.; Fuhrmann, H.

Cobalt disilicide layers were produced by 70 keV Co2+ focused ion beam implantation into Si(111) at temperatures of about 400°C and subsequent annealing. The CoSi2 layer quality depends on pixel dwell-time and subtrate temperature. Only properly chosen parameters result in a continuous layer. The dwell-time (1-250 µs) and substrate temperature (355-400°C) dependence was investigated by scanning electron microscopy, reflectivity measurements and Rutherford backscattering spectroscopy/channeling. The results show that the irradiation damage increases with dwell-time and decreases with temperature, indicating an interplay between the damage creation rate and the dynamic annealing rate. Already after implantation of less than a tenth part of the dose required for continuous layer formation, the quality of the resulting CoSi2 layer is predertermined.

  • Nuclear Instruments and Methods in Physics Research B, 148 (1999) 610-614
  • Lecture (Conference)
    11th Int. Conf. on Ion Beam Modification of Materials, Amsterdam, Aug. 31 – Sept. 4,1998

Permalink: https://www.hzdr.de/publications/Publ-1605
Publ.-Id: 1605


Die Nutzung erneuerbarer Energiequellen in Sachsen

Hackstein, G.; Riedel, J.; Rindelhardt, U.; Schwanitz, M.

Die Entwicklung und der aktuelle Stand der Nutzung erneuerbarer Energien in Sachsen wird referiert. Als besonders ausbaufähig - da an der Schwelle zur Wirtschaftlichkeit stehend - erweist sich die Windenergienutzung. Begrenzt sind danach die Ressourcen an Wasserkraft und Biomasse, deren Beitrag an einer künftigen Stromversorgung jeweils unter 2% liegen kann.

  • Wirtschaftsdienst IHK Dresden 9/1998, S. 33

Permalink: https://www.hzdr.de/publications/Publ-1604
Publ.-Id: 1604


Solarenergie - Photovoltaik

Rindelhardt, U.

Anhand ausgewählter Ergebnisse wird der aktuelle Stand der Nutzung der Photovoltaik vorgestellt. Trotz einer Reihe bemerkenswerter technischer Fortschritte bei den Hauptkomponenten und einer Vielzahl errichteter Demonstrationsanlagen liegen die Kosten von Solarstrom noch einen Faktor 10 zu hoch. Deshalb besteht nach wie vor ein erheblicher Forschungsbedarf, um diese Technologie zur Marktreife zu bringen.

  • Lecture (Conference)
    Tagung der Evangelischen Akademie Meißen, 12. - 14. Juni 1998

Permalink: https://www.hzdr.de/publications/Publ-1603
Publ.-Id: 1603


Use of the Renewable Energies in Saxony

Rindelhardt, U.

The paper gives an overview on the use of renewable energies in Saxony. Small water power stations have been used here since the last century. After a downward movement in the last decades a revitalisation is visible in the last years. In 1997 water power stations with a total power of approximately 60 MW are in operation. The wind energy use has been developed dynamically since 1992. The installed power reaches 100 MW, supplying 1% of the electricity need in Saxony.

  • Lecture (Conference)
    International Forum "Alternative Energy Sources", Lubawka (Poland), 28 - 29th May 1998

Permalink: https://www.hzdr.de/publications/Publ-1602
Publ.-Id: 1602


Ermittlung der Fehlertoleranz bei Kennlinienmessungen in Vorortuntersuchungen

Heilscher, G.; Schneider, M.; Becker, H.; Rindelhardt, U.

Voraussetzung zur Beurteilung der Leistungsfähigkeit von Photovoltaikanlagen ist die Kenntnis der Generatorleistung bei STC-Bedingungen PSTC . Da STC-Bedingungen im Betrieb der Anlage praktisch nicht auftreten, müssen die Generator-Kennlinien bei normalen Betriebsbedingungen gemessen werden und daraus mittels Näherungsverfahren die gesuchte Leistung ermittelt werden.
Im Beitrag werden die bei der Kennlinienmessung und den Umrechnungsverfahren auftretenden Fehler analysiert. Danach ist mit einem Gesamtfehler von 5,5 % zu rechnen.

  • Lecture (Conference)
    13. Symposium Photovoltaische Solarenergie, Staffelstein, 11. bis 13. März 1998, Tagungsband S. 323
  • Contribution to proceedings
    13. Symposium Photovoltaische Solarenergie, Staffelstein, 11. bis 13. März 1998, Tagungsband S. 323

Permalink: https://www.hzdr.de/publications/Publ-1601
Publ.-Id: 1601


BWR Physics and Thermohydraulics Complementary Actions to the IPSS-BWR R&D Cluster

Fiorini, G. L.; Friesen, E.; Hagen, T. V. D.; Lopez Jimenez, J.; Meloni, P.; Rindelhardt, U.

As a complement of the EU-IPSS-BWR R&D Cluster project the "BWR-Physics and Thermohydraulics Complementary Actions" contributed to answer issues which are identified for the future BWR plants: The design of innovative components, an enlarged assesment of the performances and a better understanding of the underlying physical phenomena both thermohydraulics and neutronics and the interaction of the two.
Partners from 5 EU countries were involved in the project.
The report summarizes the main results (concerning thermal valves, isolation condensers, emergency condensor, building condenser and dynamical properties of BWR) of the project.

  • Other report
    Final Report, CEA Cadarache: RT DER/SIS/LSS 98/32-1, February 1998

Permalink: https://www.hzdr.de/publications/Publ-1600
Publ.-Id: 1600


Windpotentiale in Sachsen

Hirsch, W.; Rindelhardt, U.; Brünig, D.

Im Bericht werden großflächige Untersuchungen zu windhöffigen Gebieten Sachsens vorgestellt. Für etwa 2/3 der Fläche Sachsens wurden die Windverhältnisse flächendeckend mit dem Programm WASP berechnet. Etwa 5% der Fläche Sachsens kann danach als windhöffig gelten. Als realistisches technisches Potential (Berücksichtigung von Bebauung, Naturschutzgebieten usw.) werden 5 TWh/a angesehen. Bis zum Jahr 2010 wird ein Erwartungspotential von 2 TWh/a geschätzt.

  • Other report
    Hrg.: Sächsisches Staatsministerium für Umwelt und Landesentwicklung, Reihe: Materialien zum Klimaschutz, Heft I/1997, 70 Seiten

Permalink: https://www.hzdr.de/publications/Publ-1599
Publ.-Id: 1599


Stand und Wirtschaftlichkeit der Windenergienutzung in den neuen Bundesländern

Rindelhardt, U.

Ende 1996 waren in den neuen Bundesländern insgesamt Windenergieanlagen mit einer Leistung von 274 MW in Betrieb. Der Zuwachs zum Vorjahr betrug 120 MW. In Mecklenburg-Vorpommern erreichte die Windenergie einen Anteil von 2% am Nettostromverbrauch des Landes. In der Arbeit wird ferner auf die wirtschaftlichen Rahmenbedingungen der Windenergienutzung eingegangen.

  • IDEE Informationsdienst Erneuerbare Energien, Nr. 25 (1997), S.10

Permalink: https://www.hzdr.de/publications/Publ-1598
Publ.-Id: 1598


BWR Physics and Thermohydraulics Complementary Actions to the BWR R & D Cluster

Fiorini, G. L.; Friesen, E.; Hagen, T. V. D.; Lopez Jimenez, J.; Meloni, P.; Rindelhardt, U.

An overview is given on the EU-IPSS-BWR R&D Cluster project "BWR-Physics and Thermohydraulics Complementary Actions". Six institutes/companies from 5 countries are working on three main topics:
- Design of innovative components (thermal valves, emergency condensers, isolation condensers and building condensers)
- Enlarged assesment of the performances of the innovative components
- Understanding of the physical phenomena which determine the dynamical behaviour of BWRs.
Selected results of the different topics are presented.

  • Lecture (Conference)
    Proceedings of the FISA-97 Symposium on EU Research on Severe Accidents Luxembourg, 17 to 19 November, 1997
  • Contribution to proceedings
    Proceedings of the FISA-97 Symposium on EU Research on Severe Accidents Luxembourg, 17 to 19 November, 1997

Permalink: https://www.hzdr.de/publications/Publ-1597
Publ.-Id: 1597


5 Years of Operational Experience in the German 1000-Roof-Programme: Results of Monitoring and Inspection

Becker, H.; Kiefer, K.; Hoffmann, V. U.; Rindelhardt, U.; Heilscher, G.

Within the framework of the German 1000-Roofs-PV-Programme, a total of 2011 grid connected PV systems with a total output of approximately 5.3 MWp were installed on the roofs of private houses. In addition to the recording and evaluation of the system data, another primary objective of the programme is the technical inspection of the PV systems and, in particular, the components used such as solar modules, cables, wires, diodes, fuses, terminals, overvoltage protection devices,DC isolating device and inverters. As some of the PV systems have now been in operation for as long as five years, it has been possible to gain valuable experience with regard to material time-to-failure, installation, environmental influences, maintenance, user behavior as well as on the stability and long term performance of the components used.

  • Lecture (Conference)
    Proceedings of the 14th European Photovoltaic Solar Energy Conference and Exhibition, Barcelona (Spain), 30 June - 4 July 1997, Volume II, p. 1677
  • Contribution to proceedings
    Proceedings of the 14th European Photovoltaic Solar Energy Conference and Exhibition, Barcelona (Spain), 30 June - 4 July 1997, Volume II, p. 1677

Permalink: https://www.hzdr.de/publications/Publ-1596
Publ.-Id: 1596


Technische Überprüfung von Photovoltaik-Systemen

Heilscher, G.; Schneider, M.; Pfatischer, R.; Feneberg, M.; Becker, H.; Rindelhardt, U.

Die Erfahrungen der Vermessung und von durchgeführten Vorort-Inspektionen an mehr als 100 PV-Anlagen zeigen die derzeit noch bestehende Notwendigkeit der Durchführung solcher Inspektionen. Das Ziel besteht in der Gewährleistung der Funktion und der Qualität des Gesamtsystems. Auf einzelne häufiger anzutreffende Fehlerquellen wird detailliert eingegangen.

  • Lecture (Conference)
    12. Symposium Photovoltaische Solarenergie, Staffelstein, 26. - 28. 2. 1997, Tagungsband S. 140
  • Contribution to proceedings
    12. Symposium Photovoltaische Solarenergie, Staffelstein, 26. - 28. 2. 1997, Tagungsband S. 140

Permalink: https://www.hzdr.de/publications/Publ-1595
Publ.-Id: 1595


Windmeßprogramm Sachsen, Teil II

Hirsch, W.; Rindelhardt, U.

Im Bericht werden flächendeckende Berechnungen des Windpotentials in ausgewählten Gebieten Sachsens vorgestellt. Dazu wurden vorliegende Meßwerte aufbereitet und als Atlasdateien für das Windatlasprogramm WASP allgemein zugänglich gemacht. Dies schließt auch Untersuchungen zu den zugehörigen Repräsentanzgebieten ein. Es wird gezeigt, das mit modernen Windenergieanlagen in Sachsen Erträge bis 2000 Vollbenutzungsstunden und mehr erreicht werden können.

  • Other report
    Abschlußbericht, Sächsisches Staatsministerium für Umwelt und Landesentwicklung (Hrsg.) (Materialien zum KLlimaschutz 1/1996), Dresden, November 1996

Permalink: https://www.hzdr.de/publications/Publ-1593
Publ.-Id: 1593


Energy Problems of the United Germany

Häfele, W.; Rindelhardt, U.

After the reunification of Germany, the energy situation in Germany has changed and particularly so in eastern Germany. There the demand for electric energy has suddenly decreased owing to industrial closures and accordingly, for this and for environmental reasons, the production of lignite has decreased as well. All nuclear capacity was shut down. Instead, a number of very modern high-performance coal-fired plants are being installed that also allow a sharp reduction of air pollution. Naturally, a modernisation and integration of the electrical grid is under way.

  • Paper presented at the SEC IFPA Meeting "Energy Strategy of the Countries with Transitional Economics", held at Moscow, June 24 - 25, 1993, Perspectives in Energy 2 (1993), p. 369
  • Lecture (Conference)
    Paper presented at the SEC IFPA Meeting "Energy Strategy of the Countries with Transitional Economics", held at Moscow, June 24 - 25, 1993

Permalink: https://www.hzdr.de/publications/Publ-1592
Publ.-Id: 1592


Fluorine-18 Labelling of Neurotensin Analogues for the Development of Tumour Imaging Agents

Scheunemann, M.; Mäding, P.; Steinbach, J.; Bergmann, R.; Iterbeke, K.; Tourwe, D.; Johannsen, B.

A promising approach for tracking tumours is to use radiolabelled derivatives of peptides such as Neurotensin (NT). This neuropeptide exhibits a high specific affinity to receptors located on various tumours like small cell lung carcinoma or human colon carcinoma. In order to develop a radiotracer to image the neurotensin receptor with PET the hexapeptide NT(8-13) and derivatives, such as pseudopeptides [Arg8psi(CH2NH)Arg9]NT(8-13) and [NMe-Arg8]NT(8-13) may serve as valuable starting materials.
Our labelling experiments revealed that [18F]SFB reacts with N-terminal Arg-peptides like NT(8-13) or the metabolically stabilized pseudopeptide [Arg8psi(CH2NH)Arg9]NT(8-13) with reasonable to good chemoselectivities in aqueous buffered solutions at pH values between 7.2 and 8.3. The radioactive product was identified by chromatographic comparison with a reference compound. The reactions carried out with nonradioactive SFB were shown to give the corresponding 4-FB peptides of which their structural identity was confirmed by proton NMR and MS studies. In summary the desired products of the reaction of [18F]SFB with NT(8-13) as well as [Arg8psi(CH2NH)Arg9]NT(8-13) were obtained after HPLC purification with r.c.y. of up to 43 % (related to [18F]SFB; decay corrected) within 80 min.

Keywords: Neurotensin(8-13); 18F-labelling; [18F]SFB; neurotensin receptor; pseudopeptide

  • Poster
    13th International Symposium of Radiopharmaceutical Chemistry, St Louis June 27 - July 1, 1999
  • Abstract in refereed journal
    J. Labelled Compd. Radiopharm. 42 (1999) S713-S714

Permalink: https://www.hzdr.de/publications/Publ-1590
Publ.-Id: 1590


Die Synthese von 18F-markierten Derivaten des Neurotensins für die Entwicklung neuartiger Radiotracer zur Diagnose von Tumoren

Scheunemann, M.; Mäding, P.; Steinbach, J.; Bergmann, R.; Iterbeke, K.; Tourwe, D.; Johannsen, B.

Neurotensin (NT) ist ein regulatorisches Tridekapeptid (Pyr-Leu-Tyr-Glu-Asn-Lys-Pro-Arg-Arg-Pro-Tyr-Ile-Leu), das bei Säugetieren sowohl im Zentralen Nervensystem als auch im Intestinaltrakt gebildet wird. Membranrezeptoren für dieses Peptid finden sich in verschiedenen Geweben. Insbesondere in manchen Tumoren, u.a. dem kleinzelligen Lungenkarzinom und dem Karzinom der Bauchspeicheldrüse werden Neurotensinrezeptoren verstärkt exprimiert. Das Ziel unserer Untersuchungen bestand darin, das biologisch aktive Hexapeptid NT(8-13) mit dem Isotop 18F in möglichst hoher Chemo- und Regioselektivität für die Anwendung in der Positronen Emissions Tomographie zu markieren. Die Umsetzung von NT(8-13) mit [18F]SFB gelang in wässrigem Puffer bei pH 7.2 - 8.3. Das Reaktionsprodukt 4-[18F]FB-NT(8-13) wurde über eine semipräparative HPLC an RP-18 gereinigt und fällt mit einer radiochemischen Reinheit von >99.5% und einer radiochemischen Ausbeute von 43% (zerfallskorrigiert) an. Die Substanz entspricht in ihrer chromatographischen Charakteristik der Referenzsubstanz, die durch Umsetzung von NT(8-13) mit nichtradioaktivem SFB gewonnen wurde. Durch Einbeziehen von Pseudopeptiden wie [Arg8Psi(CH2NH)Arg9]NT(8-13) möchten wir dem Problem der metabolischen Instabilität natürlicher Peptide in vivo begegnen.

Keywords: Neurotensin (8-13); Neurotensinrezeptor; Positronen Emissions Tomographie; [18F]SFB; Pseudopeptid

  • Poster
    4. Deutsches Peptidsymposium 21. - 24. März 1999 / Programm und Abstracts S. 134.

Permalink: https://www.hzdr.de/publications/Publ-1589
Publ.-Id: 1589


Revised Performance Data of Small Grid Connected PV Systems Based on in situ Measurements

Rindelhardt, U.; Teichmann, G.; Decker, B.; Grochowski, J.

The mean annual yield (700 kWh/a*kWp) and performance ratio (65%) of small grid connected PV systems which were installed within the 1000-Roofs-Programme in Germany are lower than expected. By investigating the parameters determining the performance ratio it could be shown that for well designed PV systems the PR should range within 70 to 80 %. The real power of the PV arrays as the most critical parameter of the performance ratio was measured with a newly developed PV system analyzer. In most investigated systems the measured power was 10 to 20 % lower than the nominal power. The revised performance data based on the measurements agree with the above given values. Based on a typical irradiation of 1100 kWh/m2 in module plane a mean annual yield of more than 800 kWh/a*kWp can be expected.

Keywords: Small grid connected PV systems - 1:Performance - 2:PV Array - 3

  • Poster
    Proceedings of the 14th European Union Photovoltaic Solar Energy Conference and Exhibition, Barcelona (Spain), 30. June - 04. July 1997, Volume II, p. 2652
  • Contribution to proceedings
    Proceedings of the 14th European Union Photovoltaic Solar Energy Conference and Exhibition, Barcelona (Spain), 30. June - 04. July 1997, Volume II, p. 2652

Permalink: https://www.hzdr.de/publications/Publ-1588
Publ.-Id: 1588


Measured Hot Water Consumption in Appartment Buildings as Key Design Parameter for Solar collector Installations

Mack, M.; Schwenk, C.; Vanoli, K.; Luboschik, U.; Schalajda, P.; Schnauss, M.; Valentin, G.; Gassel, A.; Rindelhardt, U.

The increasing number of solar collector installations for larger appartment buildings proves that solar thermal energy is a favourable option for this type of water heaters. When operated in a preheat-mode such installations can reach a high collector loop efficiency which - besides the lower specific costs of material and installation - provides additional cost benefit. However, there may be a substantial decrease in collector loop efficiency which causes a reduction of solar yield when the actual hot water consumption stays far behind the design value. Therefore it is important to review the available data of hot water consumption in appartment buildings.
The present contribution presents and reviews recently measured hot water consumption data from various appartment buildings at different locations in Germany. The objects represent a broad choice of different design situations, varying e. g. in the number of appartments, the size of the appartments, the specific number of occupants per appartment and the social environment of the occupants. The locations comprise urban and rural dwellings. The data very recent (the earliest data taken in 1992) and therefore reflect today's lifestyle.

  • Lecture (Conference)
    Proceedings of Eurosun 96, Freiburg, 16. - 19. 09. 1996, Volume 1, p. 246
  • Contribution to external collection
    Proceedings of Eurosun 96, Freiburg, 16. - 19. 09. 1996, Volume 1, p. 246

Permalink: https://www.hzdr.de/publications/Publ-1587
Publ.-Id: 1587


Numerical Simulation of the Emergency Condenser of the SWR1000

Krepper, E.; Schaffrath, A.; Aszódi, A.

The SWR1000 is a new innovative boiling water reactor concept, which is developed by Siemens AG. This concept is characterized in particular by passive safety systems (e.g. four emergency condensers, four building condensers, eight passive pressure pulse transmitters, six gravity-driven core flooding lines). In the framework of BWR Physics and Thermohydraulic Complementary Action (BWR-CA) to the EU BWR R&D Cluster emergency condenser tests were performed by Forschungszentrum Jülich at the NOKO test facility. In this paper post test calculations with ATHLET are presented, which aim at the determination of the removable power of the emergency condenser and its operation mode. The 1D thermal-hydraulic code ATHLET was extended by the module KONWAR for the calculation of the heat transfer coefficient during condensation in horizontal tubes. In addition, results of CFD-calculations using the code CFX-4 are presented, which investigate the natural convection during the heat up process at the secondary side of the NOKO test facility.

Keywords: BWR; emergency condenser; condensation in horizontal tubes; 1D-modelling; heat transfer in large pools; computational fluid dynamics

  • Nuclear Science and Engineering 135 (2000) No.3 267-279

Permalink: https://www.hzdr.de/publications/Publ-1586
Publ.-Id: 1586


Lifetimes and collectivity of low-lying states in 115Sn

Lobach, Y. N.; Käubler, L.; Schwengner, R.; Pasternak, A. A.

  • Physical Review C, Volume 59, Number 4, April 1999, 1975-1983

Permalink: https://www.hzdr.de/publications/Publ-1585
Publ.-Id: 1585


High-fold Gamma-ray spectroscopy of 117I: Coexistence of collective and noncollective structures

Paul, E. S.; Fossan, D. B.; Hauschild, K.; Hibbert, I. M.; Nolan, P. J.; Schnare, H.; Sears, J. M.; Thorslund, I.; Wadsworth, R.; Wilson, J. N.; Ragnarsson, I.

  • Physical Review C, Volume 59, Number 4, April 1999, 1984-1998

Permalink: https://www.hzdr.de/publications/Publ-1584
Publ.-Id: 1584


Complete scissors mode strength in heavy deformed odd-mass nuclei: a case study of 165Ho and 169Tm

Huxel, N.; von Brentano, P.; Eberth, J.; Enders, J.; Herzberg, R.-D.; von Neumann-Cosel, P.; Nicolay, N.; Pietralla, N.; Prade, H.; Rangacharyulu, C.; Reif, J.; Richter, A.; Schlegel, C.; Schwengner, R.; Skoda, S.; Thomas, H. G.; Wiedenhöver, I.; Winter, G.; Zilges, A.

  • Nuclear Physics A 645 (1999) 239-261

Permalink: https://www.hzdr.de/publications/Publ-1583
Publ.-Id: 1583


Capillary electrophoresis of 99mtechnetium radiopharmaceuticals

Jankowsky, R.; Noll, B.; Johannsen, B.

Diagnostically used 99mTc kit radiopharmaceuticals were analyzed using capillary zone electrophoresis with radioactivity detection: 99mTc-bis(bis(2-ethyloxyethyl)phosphino)ethane (99mTc-Myoview, 99mTc-Tetrofosmin), 99mTc-trans(1,2-bis(dehydro-2,2,5,5,-tetramethyl-3-furanone-4-methylene-amino)ethane)-tris(3-methoxy-1-propyl)phosphine) (99mTc-Technescan Q12, 99mTc-Furifosmin), 99mTc-methoxyisobutylisonitrile (99mTc-MIBI), 99mTc-L,L-ethylenecysteine diethylester dimer (99mTc-ECD), 99mTc-d,l-hexamethylene propyleneamine oxime (99mTc-HMPAO), 99mTc-diethylenetriaminepentaacetic acid (99mTc-DTPA), 99mTc-ethylene hepatobiliary iminodiacetic acid (99mTc-EHIDA), 99mTc-L,L-ethylenecysteine (99mTc-EC), 99mTc-mercaptoacetylglycylglycylglycine (99mTc-MAG3), 99mTc-dimercaptosuccinic acid (99mTc-DMSA), 99mTc-methylene diphosphonate (99mTc-MDP) and 99mNaTcO4. A pressure-driven capillary zone electrophoresis was employed to detect small anions of high electrophoretic mobility and cations within one run. Effective 99mTc complex charges could be determined by a neutral internal standard. All complexes showed the expected electrophoretic behaviours in view of their charges. Pure products were obtained for the majority of the studied complexes. In the case of 99mTc-Q12, 99mTc-EHIDA and 99mTc-MDP, complex mixtures were detected. The high potential of CE for the analysis of 99mTc radiopharmaceuticals could be shown.

Keywords: Radiopharmaceuticals; 99mTechnetium

  • Journal of Chromatography B, 724 (1999) 365-371

Permalink: https://www.hzdr.de/publications/Publ-1582
Publ.-Id: 1582


Relation between brain tissue pO2 and dopamine synthesis of basal ganglia - A 18FDOPA-PET study in newborn piglets

Bauer, R.; Brust, P.; Walter, B.; Vorwieger, G.; Bergmann, R.; Füchtner, F.; Steinbach, J.; El-Hallag, E.; Fritz, A.; Johannsen, B.; Zwiener, U.

Perinatal hypoxic-ischemic cerebral injury is a major determinant of neurologic morbidity and mortality in the neonatal period and later in childhood. There is evidence that the dopaminergic system is sensitive to oxygen deprivation. However, the respective enzyme activities have not been measured in the living neonatal brain yet.
In this study, we have used 18F-labelled 6-fluoro-L-3,4-dihydroxyphenylalanine (FDOPA) together with Positron-Emission-Tomography (PET) to estimate the activity of the DOPA decarboxylase (DDC), the ultimate enzyme in the synthesis of dopamine (DA), in the brain of newborn piglets under normoxic and moderate asphyxial conditions.
The study was performed on 8 newborn piglets (2-5 days old). In each piglet two PET studies were performed under control conditions and during 2-hour asphyxia. Simultaneously, brain tissue pO2 (LICOX pO2 Monitor, GMS mbH, Kiel-Mielkendorf, Germany) was recorded, brain venous blood samples were obtained from sagittal sinus, and cerebral blood flow (CBF) was measured with col-ored microspheres. Cerebral metabolic rate of oxygen (CMRO2) was determined as the product of CBF and cerebral AVDO2. Asphyxia was induced by lowering the inspired fraction of oxygen from 0.35 to 0.12 and adding about 6 % CO2 to the inspired gas, which resulted in moderate hypoxemia (39±6 mm Hg), hypercapnia (73±2 mm Hg) and a progredient combined respiratory/metabolic aci-dosis (p<0.01).
Asphyxia elicited an more than 3-fold increase of the CBF (p<0.01) so that CMRO2 remained un-changed throughout the asphyxial period. Despite this, brain tissue pO2 was reduced from 19±4 mm Hg to 6±3 mm Hg (p<0.01). Blood-brain transfer of FDOPA as well as permeability-surface area product (PS) from striatum were unchanged. However, striatal synthesis rate of FDA (fluoro-dopamine) from FDOPA (k3) was significantly increased (p<0.01).
This increase of the DDC activity due to moderately reduced brain tissue pO2 at unchanged CMRO2 may contribute to the ...

Keywords: DOPA decarboxylase activity; brain tissue pO2; cerebral blood flow; CMRO2; Positron Emission Tomography; Colored Microspheres; Newborn Piglets

  • J. Perinat. Med. 28 (2000) 54-60

Permalink: https://www.hzdr.de/publications/Publ-1581
Publ.-Id: 1581


Proceedings of the Miniworkshop "Electromagnetic Radiation off Colliding Hadron Systems: Dileptons and Bremsstrahlung"

Grosse, E.; Kämpfer, B.

Since several years various groups of the Institute of Nuclear und Hadron Physics at Forschungszentrurn Rossendorf (FZR) are involved in medium energy physics projects where electromagnetic signals play a role:
(i) pp bremsstrahlung experiments at COSY-ToF have been proposed by a group from Dresden with FZR participation, and a large part of the ToF detector system has been
built in Rossendorf.
(ii) The FZR is presently building one of the large wire chamber planes for the HADES detector at GSI and is also actively taking part in the HADES commissioning.
(iii) The theory group here at Rossendorf is working in the field of dilepton production and other electromagnetic processes.
To discuss the research in these fields with colleagues from other places and to coordinate the efforts this mini-workshop was organized. The idea was to discuss the results of the experiments at different accelerators, the status of the calculations and the plans for future investigations. Besides bremsstrahlung special emphasis will be on dielectron production; other processes with electromagnetic signals (like vector-meson production) have also been discussed.

  • Open Access Logo Wissenschaftlich-Technische Berichte / Forschungszentrum Rossendorf; FZR-258 April 1999
    ISSN: 1437-322X

Downloads:

Permalink: https://www.hzdr.de/publications/Publ-1579
Publ.-Id: 1579


Messtechniken in der Zweiphasenströmung

Prasser, H.-M.

Heutige thermohydraulische Rechenprogramme, wie sie für die Auslegung und Si-cher-heitsanalyse chemisch/verfahrenstechnischer und nuklearer Anlagen eingesetzt wer-den, weisen entscheidende Defizite auf. Die Übertragbarkeit der Rechenergebnisse ist nur auf geometrische und thermohydraulische Verhältnisse gegeben, für die die einzelnen Komponenten des Modells adaptiert bzw. validiert wurden. Um in Zukunft eine Verbesserung der Übertragbarkeit, eine größere Nutzerunabhängigkeit der Simulationsergebnisse und eine Erhöhung der Modellgenauigkeit zu erreichen, wird weltweit auf den Übergang zu einer dreidimensionalen Modellierung mit Hilfe von CFD-Codes gesetzt. Dieses Ziel setzt neue Maßstäbe für die meßtechnische Instrumentierung der Experimente, die für die Entwicklung und Validierung der hierfür erforderlichen Modelle und Computercodes erforderlich sind. Bisher lag der Schwerpunkt auf der Messung von Massen-, Energie- und Impulsbilanzen über ganze Strömungskanäle und Geschwindigkeits- bzw. Dampfgehaltsverteilungen wurden vorrangig zur Ermittlung dieser Bilanzen und für ein qualitatives Verständnis der ablaufenden Prozesse erfaßt. Nun kommt es darauf an, die Verteilungen der Meßgrößen in einer räumlichen und zeitlichen Auflösung zu messen, die lokal quantitative Aussagen über Zwischenphasen-Austauschterme und einen Vergleich mit den dreidimensionalen Simulationsrechnungen erlauben. In den nachfolgenden Kapiteln werden die neuen Anforderungen an die Zweiphasenmeßtechnik am Beispiel der Messung von Phasenverteilungen definiert und einzelne, besonders vielversprechende Entwicklungs-richtungen diskutiert. Als eigenen Beitrag werden die Rossendorfer Arbeiten zum Gittersensor vorgestellt.

Keywords: Zweiphasenmeßtechnik; Tomographie; Gittersensor; Blasengrößenverteilung; Gasgehalt; Phasenanteile

  • Lecture (Conference)
    Jahrestagung Kerntechnik, Karlsruhe, 18.-21.05.1999, FACHSITZUNG, Neue Ergebnisse aus F + E zur Fluiddynamik und Reaktorphysik, INFORUM GmbH, Bonn, Juni 1999
  • Contribution to proceedings
    Jahrestagung Kerntechnik, Karlsruhe, 18.-21.05.1999, FACHSITZUNG, Neue Ergebnisse aus F + E zur Fluiddynamik und Reaktorphysik, INFORUM GmbH, Bonn, Juni 1999

Permalink: https://www.hzdr.de/publications/Publ-1578
Publ.-Id: 1578


3D Nodal Expansion Method HEXNEM for Solution of the Neutron Diffusion Equation in Hexagonal Geometry

Grundmann, U.

The nodal expansion method (NEM) used in the hexagonal version of the code DYN3D is based on the node averaged values of fluxes in the node volume and averaged values of fluxes and currents at the interfaces of the nodes [1]. The 3-dimensional neutron diffusion equation for two energy groups is split into a 2-dimensional equation in the hexagonal plane solved with the help of Bessel functions and a 1-dimensional equation in axial direction solved by polynomial expansion. The two equation systems are coupled by the transversal bucklings. The accuracy of this method is sufficient for the VVER-440 where the assembly pitch is 14.7 cm. The assemblies of the VVER-1000 have a larger pitch of 24.1 cm. Comparing with mathematical benchmarks for the VVER-1000 the maximal deviation of powers is in the order of 5%. The new nodal expansion method HEXNEM presented here uses a different flux expansion in the nodes. In addition to the average values at the interfaces of the hexagon the values at the corner points are included, too. It is shown that the accuracy is improved for the VVER-1000 problems.

Keywords: neutron diffusion theory; nodal method; hexagonal geometry; two energy groups

  • Lecture (Conference)
    Jahrestagung Kerntechnik '99, 18. - 20. Mai, 1999, Karlsruhe, S. 15 - 18
  • Contribution to proceedings
    Jahrestagung Kerntechnik '99, 18. - 20. Mai, 1999, Karlsruhe, S. 15 - 18

Permalink: https://www.hzdr.de/publications/Publ-1577
Publ.-Id: 1577


Analysis of the Exercise 2 of the OECD - MSLB Benchmark with the Code DYN3D/R

Grundmann, U.; Kliem, S.; Rohde, U.

The Cartesian version of the 3D core model DYN3D coupled with the thermohydraulic plant
model ATHLET will be used for the analysis of the OECD Main Steam Line Break (MSLB)
Benchmark which is based on real plant design and operational data of the TMI-1 PWR. The
three exercises of the benchmark are a point kinetics plant simulation (exercise 1), a
coupled 3D neutronics/core thermal-hydraulics evaluation of the core response (exercise 2)
and a best estimate coupled core-plant transient analysis (exercise 3). The presented
calculations of the exercise 2 are performed with the DYN3D code alone. The core boundary
conditions provided by calculations of the Penn State University with the TRAC-PF1/NEM code
system are used as input for the two scenarios of this exercise. Considering the best
estimate case (scenario 1) the reactor does not become critical during the transient.
Defining a more serious test for the codes, the efficiency of the control rods was
decreased to obtain a return to power in the transient (scenar io 2). The influence of
different thermohydraulic modelling on the results is investigated with the help of the
DYN3D calculations for scenario 2. The core averaged values as the total nuclear power or
the reactivity show a low sensitivity against the variation of the thermohydraulic model.
Considering local values as the maximum nodal Doppler temperature an impact of the
thermohydraulic model is observed.

Keywords: main steam line break; benchmark; pressurized water reactor; coupled neutronic thermohydraulic codes; DYN3D; ATHLET; 3-dimensional

  • Poster
    M&C'99 - Madrid International Conference on Mathematics and Computation, Reactor Physics and Enviromental Analysis in Nuclear Applications, pp. 1794-1803, Madrid, 27-30 September 1999
  • Contribution to proceedings
    M&C'99 - Madrid International Conference on Mathematics and Computation, Reactor Physics and Enviromental Analysis in Nuclear Applications, pp. 1794-1803, Madrid, 27-30 September 1999

Permalink: https://www.hzdr.de/publications/Publ-1576
Publ.-Id: 1576


Plasma based ion implantation

Möller, W.

  • Book (Authorship)
    H. Schlüter and A. Shivarova (eds.): Advanced Technologies Based on Wave and Beam Generated Plasmas, 191-244, 1999 Kluwer Academic Publishers
  • Lecture (Conference)
    NATO ASI, "Advanced Technologies Based on Wave and Beam Generated Plasmas", Sozopol, Bulgaria, May 28 - 30, 1998

Permalink: https://www.hzdr.de/publications/Publ-1575
Publ.-Id: 1575


Use of Instrumented Charpy Test for Determination of Ductile Crack Initiation Toughness

Viehrig, H.-W.; Böhmert, J.; Richter, H.; Valo, M.

The present paper reports the determination of dynamic crack initiation (Jid) values using the instrumented Charpy test. Under the condition of the impact bending test the critical step for evaluating of Jid is detection of ductile crack initiation point on the impact load displacement curve. In this paper the crack initiation is determined by using emission of acoustic waves (AE). Different kind of AE events can be observed during loading of a precracked and side-grooved Charpy size specimen. It was shown that characteristic AE signals appear in the vicinity of crack initiation for the first time. These results have been verified by the results of COD measurements using the inverted impact pendulum developed and installed by VTT Espoo/Finland (VTT Tester). Additionally "Cleavage R-Curves" (Ju- a), have been evaluated and the physical crack initiation toughness (JidSZW) was deduced by measurement of the stretch zone width (SZW).

Keywords: dynamic fracture toughness; ductile crack initiation; J-integral; single specimen method; multiple specimen method; acoustic emission; instrumented impact testing; crack extension curve

  • Book (Authorship)
    Pendulum Impact Testing: A Century of Progress, ASTM STP 1380, T. Siewert ans M.P. Manahan, Sr., Eds., American Society for Testing and Materials, West Conshohocken, PA, 2000, pp. 354-365

Permalink: https://www.hzdr.de/publications/Publ-1572
Publ.-Id: 1572


Can core/shell nanocrystals be formed by sequential ion implantation? Predictions from kinetic lattice Monte Carlo simulations

Strobel, M.; Heinig, K.-H.; Möller, W.

  • Nuclear Instruments and Methods in Physics Research B 148 (1999) 104-109
  • Lecture (Conference)
    11th Int. Conf. on Ion Beam Modification of Materials, Amsterdam, The Netherlands, Aug. 31 - Sept. 4, 1998

Permalink: https://www.hzdr.de/publications/Publ-1570
Publ.-Id: 1570


Institute of Ion Beam Physics and Materials Research; Annual Report 1998

von Borany, J.; Jäger, H.-U.; Möller, W.; Wieser, E.

  • Open Access Logo Wissenschaftlich-Technische Berichte / Forschungszentrum Rossendorf; FZR-253 März 1999
    ISSN: 1437-322X

Downloads:

Permalink: https://www.hzdr.de/publications/Publ-1569
Publ.-Id: 1569


CFD-Calculations to a Core Catcher Benchmark

Willschütz, H.-G.

There are numerous experiments for the exploration of the corium spreading behaviour, but comparable data have not been available up to now in the field of the long term behaviour of a corium expanded in a core catcher. The difficulty consists in the experimental simulation of the decay heat that can be neglected for the short-run course of events like relocation and spreading, which must, however, be considered during investigation of the long time behaviour.
Therefore the German GRS, defined together with Battelle Ingenieurtechnik a benchmark problem in order to determine particular problems and differences of CFD codes simulating an expanded corium and from this, requirements for a reasonable measurement of experiments, that will be performed later.
First the finite-volume-codes Comet 1.023, CFX 4.2 and CFX-TASCflow were used. To be able to make comparisons to a finite-element-code, now calculations are performed at the Institute of Safety Research at the Forschungszentrum Rossendorf with the code ANSYS/FLOTRAN.For the benchmark calculations of stage 1 a pure and liquid melt with internal heat sources was assumed uniformly distributed over the area of the planned core catcher of a EPR plant.
Using the Standard-k-e-turbulence model and assuming an initial state of a motionless superheated melt several large convection rolls will establish within the melt pool. The temperatures at the surface do not sink to a solidification level due to the enhanced convection heat transfer. The temperature gradients at the surface are relatively flat
while there are steep gradients at the ground where the no slip condition is applied. But even at the ground no solidification temperatures are observed.
Although the problem in the ANSYS-calculations is handled two-dimensional and not three-dimensional like in the finite-volume-codes, there are no fundamental deviations to the results of the other codes.

Keywords: corium pool; internal heat sources; CFD-Calculations with different codes; long term behaviour; core catcher

  • Open Access Logo Wissenschaftlich-Technische Berichte / Forschungszentrum Rossendorf; FZR-257 April 1999
    ISSN: 1437-322X

Downloads:

Permalink: https://www.hzdr.de/publications/Publ-1568
Publ.-Id: 1568


1:5 scaled Plexiglas Mixing Model of the PWR Konvoi

Höhne, T.

The coolant mixing in the downcomer and lower plenum depends significantly on the construction of the reactor vessel and on the instantaneous flow conditions. Therefore the Institute for Safety Research of Forschungszentrum Rossendorf has constructed a 1:5 mixing test facility representing the geometry of the German Konvoi type pressurized water reactor. The mock-up of the test facility and the measuring systems are explained in the poster.

Keywords: PWR; Coolant Mixing

  • Poster
    International Conference on Nuclear Engineering (ICONE-7), April 19-23 1999, Tokio, Japan
  • Lecture (Conference)
    International Conference on Nuclear Engineering (ICONE-7), April 19-23,1999, Tokio, Japan

Permalink: https://www.hzdr.de/publications/Publ-1566
Publ.-Id: 1566


Das INTRANET/INTERNET-Angebot der Zentralbibliothek des Forschungszentrums Rossendorf

Grünberg, H.; Rücker, C.

In einer ersten und noch immer währenden Phase bewirkten die Informationstechnologien, dass die klassischen Geschäftsgänge von Bibliotheken rechnergestützt durchgeführt werden können. Das betrifft die Erwerbung, die Katalogisierung, die Nutzerverwaltung, den Aufbau von Online-Katalogen, die Zeitschriftenverwaltung, die Budgetverwaltung, die Fernleiheprozeduren u.a. Bibliotheksroutinen. Mit den sich schnell entwickelnden Technologien des INTERNET und des INTRANET werden für wissenschaftliche Bibliotheken neue Aufgabenfelder geschaffen. Diese entwickeln und erweitern sich sehr dynamisch. Für wissenschaftliche Bibliotheken, die in der Regel ein modernes wisschenschaftlich-technisches Umfeld haben, stellt diese Entwicklung eine grosse Herausforderung dar. Wenn sie diese Herausforderung annehmen, dann haben sie ein gute Chance auch weiterhin ein anerkannter Partner im Forschungsprozeß ihrer Trägereinrichtungen zu bleiben. Die Zentralbibliothek des Forschungszentrums Rossendorf bietet unter Nutzung dieser modernen Technologien und ausgehend von den Bedürfnissen der Wissenschaftler neue und nützliche Dienste an. Diese Dienste basieren auf informations- und literaturbezogenen Inhouse-Datenbanken. Diese Datenbanken werden dezentral gepflegt (die Wissenschaftler geben über WEB-Klients selbst in diese Datenbanken Datensaetze ein). Sie stehen ueber das INTRANET allen autorisierten Nutzern zu Verfügung. Inzwischen sind mehrere solcher Datenbanken zum Rossendorfer Virtuellen Katalog (ROKAT) verknüpft. Mit der Pflege der Inhouse-Datenbanken kommt die Bibliothek einer von ihr erwarteten Aufgabe, der Dokumentation der wissenschaftlichen Leistungsfähigkeit der Forschungseinrichtung in eleganter und personell verkraftbaren Weise nach. Im Vortrag wird auf die Persönliche Literaturdatenbank, eine Datenbank, die für Wissenschaftler geschaffen wurde und die gleichermaßen der Bibliotheksarbeit dient, näher eingegangen.

  • Lecture (others)
    Vortrag HTW-Leipzig, Fachbereich Buch und Museum am 20.04.1999

Permalink: https://www.hzdr.de/publications/Publ-1565
Publ.-Id: 1565


Surface sensitivity of ion implanted titanium to hydroxyapatite formation

Pham, M. T.; Matz, W.; Reuther, H.; Richter, E.; Steiner, G.; Oswald, S.

Titanium surfaces containing CaO and P2O5 were prepared by ion implantation of Ca and P and subsequent oxidation. Their reactivity to form hydroxyapatite was examined by in situ microscopically recording the surface mineralization in a simulated body fluid. The ion implanted surfaces exhibit enhanced mineralization by inducing heterogeneous nucleation, growth, and proliferation of hydroxyapatite, relative to a control sample of pure Ti. The surface induced reactivity was shown to relate to the mineral precursors Ca2+ and (HPO4)2- directly supplied from the surface and the substrate-mediated nucleation by hydroxylated surface TiO2.

Keywords: biomaterials; titanium; hydroxyapatite

  • Journal of Materials Science Letters 19 (2000) 313
  • Mater. Sci. Lett. 19 (2000) 443-445

Permalink: https://www.hzdr.de/publications/Publ-1564
Publ.-Id: 1564


Synthesis and preliminary pharmacological investigations of 1-(1,2-dihydro-2-acenaphthylenyl)piperazine derivatives as potential atypical antipsychotic agents in mice

Srinivas, P.; Subramanian, A. R.; Brust, P.; Raghavan, S. A. V.; Rangisetty, J. B.; Gupta, C. N. V. H. B.; Sridhar, N.; Veeranjaneyulu, A.; Parimoo, P.

In research towards the development of new atypical antipsychotic agents, one strategy is that the dopaminergic system can be modulated through manipulation of the serotonergic system. The synthesis and preliminary pharmacological evaluation of a series of potential atypical antipsychotic agents based on the structure of 1-(1,2-dihydro-2-acenaphthylenyl) piperazine 7 is described. 7e from this series showed significant affinities at the 5-HT1A and 5-HT2A receptor and moderate affinity at the D2 receptor. 7e exhibits a high reversal of catalepsy induced by haloperidol indicating its atypical antipsychotic nature.

Keywords: 1-(1,2-dihydro-2-acenaphthylenyl) piperazine; 5-Hydroxytryptamine; catechol mimics; dopamine; atypical antipsychotics

  • IL FARMACO 54 (1999) 567-572

Permalink: https://www.hzdr.de/publications/Publ-1563
Publ.-Id: 1563


Characterization of the preferred orientation in EXAFS-samples

Hennig, C.; Nolze, G.

Preferred orientation in powder samples influences extendet X-ray absorption fine structure (EXAFS) measurements due to the polarization of synchrotron radiation. The polarization effect at the uranium LIII edge EXAFS and the analysis of preferred orientation is demonstrated using the natural mineral metatorbernite. For simple textures an X-ray diffraction measurement in Bragg-Brentano geometry allows to determine the crystallite orientation basing on a full pattern refinement including a preferred orientation model according to March-Dollase.

  • NEA-Conference, Genoble 1998, NEA-Report

Permalink: https://www.hzdr.de/publications/Publ-1560
Publ.-Id: 1560


Eurokonference and NEA Workshop Actinide - XAS - 98

Reich, T.

Euroconference and NEA Workshop Actinide-XAS-98

During recent years the interest in applying synchrotron radiation techniques to the investigation of radionuclides and actinides in particular has grown rapidly. Important research topics where a molecular-level understanding is mandatory include the behavior of radionuclides in the environment, nuclear waste management, radiopharmaceutical chemistry, and general actinide chemistry and physics.

On October 4-6, 1998 the first Euroconference and NEA Workshop on Speciation, Techniques, and Facilities for Radioactive Materials at Synchrotron Light Sources, Actinide-XAS-98, took place at the ESRF/ILL site. Over 90 scientists came from 13 European countries, USA, and Japan. Among them were 22 young scientists with an average age of 26 who benefited from travel awards provided by the European Commission. The main objectives of Actinide-XAS-98 were:
- to introduce the type of information that can be obtained from synchrotron-based techniques to environmental and radionuclide scientists,
- to report the latest results on radionuclide/actinide work, and
- to inform on protocols which are in place for actinide research at several synchrotron storage rings throughout the world.

The first day had tutorial character and introduced several synchrotron radiation techniques. H. Nitsche described the sources of environmental contamination by radionuclides, the importance of understanding the chemical behavior of radionuclides under environmental conditions, and the role x-ray absorption fine-structure (XAFS) spectroscopy plays in these investigations. D.C. Koningsberger, J. Goulon, and A. Filipponi presented the physical principle of XAFS and related experimental and theoretical aspects. V.I. Nefedov gave an introduction to x-ray photoelectron spectroscopy (XPS). D.K. Shuh described the complimentary application of XPS, near-edge x-ray absorption fine structure, and x-ray emission spectroscopy on actinide materials at e ...

  • ESRF News Letter 32, 7 (1999)

Permalink: https://www.hzdr.de/publications/Publ-1559
Publ.-Id: 1559


First identification of excited states in the N=Z nucleus 70Br

Borcan, C.; Schnare, H.; Schwengner, R.; Kaeubler, L.; Ortlepp, H. G.; Doenau, F.; Grawe, H.; Skoda, S.; Eberth, J.; Haertlein, T.; Koeck, F.; Pansegrau, D.; Schwalm, D.; Moszynski, M.; Wolski, D.; Weiszflog, M.; Axelsson, A.; Napoli, D.; Gadea, A.; Wadsworth, R.; Andrejtscheff, W.

Excited states in the N=Z nucleus 70Br have been investigated using the reaction 58Ni(16O,1p3n). Gamma rays were detected with one EUROBALL CLUSTER detector and three single HPGe detectors. Charged particles and neutrons were registered with the Rossendorf silicon ball and six modules of the EUROBALL neutron wall, respectively. The identification of gamma transitions in 70Br is based on the analysis of gamma-gamma-proton-neutron coincidences. A level scheme of 70Br has been established for the first time. It shows a multiplet-like structure of probably isospin T = 0 while T = 1 isobaric analogue states are not observed.

Keywords: Nuclear structure; Gamma-ray and particle spectroscopy; N = Z nuclei; p-n interaction; T = 0 and T = 1 states

  • European Physical Journal A 5 (1999) 243-246

Permalink: https://www.hzdr.de/publications/Publ-1558
Publ.-Id: 1558


ROBL - a CRG Beamline for Radiochemistry and Materials Research at the ESRF

Matz, W.; Schell, N.; Bernhard, G.; Claußner, J.; Oehme, W.; Prokert, F.; Reich, T.; Schlenk, R.; Pröhl, D.; Funke, H.; Eichhorn, F.; Betzl, M.; Dienel, S.; Brendler, V.; Denecke, M. A.; Krug, H.; Neumann, W.; Hüttig, G.; Reichel, P.; Strauch, U.

The paper describes the Rossendorf Beamline (ROBL) built by the Forschungszentrum Rossendorf at the ESRF. ROBL comprises two different and independently operating experimental stations: a radiochemistry laboratory for X-ray absorption spectroscopy of non-sealed radioactive samples and a general purpose materials research station for X-ray diffraction and reflectometry mainly of thin films and interfaces modified by ion beam techniques. The radiochemistry set-up is worldwide an unique installation at a modern synchrotron radiation source.

Keywords: synchrotron radiation beamline; EXAFS; XANES; radiochemistry laboratory; radionuclides; X-ray diffraction and reflectometry; thin films; interfaces; melts

  • Journal of Synchrotron Radiation, 6 (1999) 1076-1085
  • Open Access Logo Forschungszentrum Rossendorf, Wissenschaftlich-Technische Berichte; FZR-256 April 1999
    ISSN: 1437-322X

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Permalink: https://www.hzdr.de/publications/Publ-1556
Publ.-Id: 1556


On the Space-Time Difference of Proton and Composite Particle Emission in Central Heavy-Ion Reactions at 400 AMeV

Kotte, R.; Barz, H. W.; Neubert, W.; Plettner, C.; Wohlfarth, D.; Alard, J. P.; Andronic, A.; Averbeck, R.; Basrak, Z.; Bastid, N.; Bendarag, N.; Berek, G.; Caplar, R.; Cindro, N.; Crochet, P.; Devismes, A.; Dupieux, P.; Dzelalija, M.; Eskef, M.; Fodor, Z.; Gobbi, A.; Grishkin, Y.; Herrmann, N.; Hildenbrand, K. D.; Hong, B.; Kecskemeti, J.; Kim, Y. J.; Kirejczyk, M.; Korolija, M.; Kowalczyk, M.; Kress, T.; Kutsche, R.; Lebedev, A.; Lee, K. S.; Leifels, Y.; Manko, V.; Merlitz, H.; Moisa, D.; Nianine, A.; Pelte, D.; Petrovici, M.; Rami, F.; Reisdorf, W.; de Schauenburg, B.; Schüll, D.; Seres, Z.; Sikora, B.; Sim, K. S.; Simion, V.; Siwek-Wilczynska, K.; Somov, A.; Stoicea, G.; Vasiliev, M. A.; Wagner, P.; Wisniewski, K.; Yang, J. T.; Yushmanov, Y.; Zhilin, A.

Small-angle correlations of pairs of nonidentical light charged particles
produced in central collisions of heavy ions
in the A=100 mass region at a beam energy of 400 AMeV are investigated with the FOPI detector system at GSI Darmstadt. The difference of longitudinal correlation functions with the
relative velocity parallel and anti-parallel to the center-of-mass velocity of the pair in the central source frame is studied. This method allows extracting the apparent
space-time differences of the emission of the charged particles. Comparing the correlations with results of a final-state interaction model delivers quantitative estimates of these asymmetries. Time delays as short as 1 fm/c or - alternatively - source radius differences of a few tenth fm are resolved.
The strong collective expansion of the participant zone introduces not only an apparent reduction of the source radius
but also a modification of the emission times. After correcting for both effects a complete sequence of space-time emission points of p, d, t, 3He, alpha particles is presented for the first time.

Keywords: Nuclear physics; Intermediate energy heavy-ion reactions; Multifragmentation; Fragment-fragment correlation; Final-state interaction; Radial flow

  • The European Physical Journal A 6 (1999) 185-195

Permalink: https://www.hzdr.de/publications/Publ-1555
Publ.-Id: 1555


Electromagnetic flow control for drag reduction and separation prevention

Weier, T.; Fey, U.; Gerbeth, G.; Mutschke, G.; Lielausis, O.; Platacis, E.

The flow of an electrically conducting fluid like sea-water can be
controlled by electromagnetic forces, i.e.~Lorentz-forces. These forces
may be generated by an appropriate chosen arrangement of permanent
magnets and electrodes. A strip like geometry as shown in fig. 1
produces a Lorentz-force with a streamwise component only. In a first
approximation this force is independent of the spanwise coordinate z and
decays exponentially with increasing wall distance y [1]. The successful
application of a surface parallel Lorentz force in streamwise direction
to control the flow around a cylinder has been demonstrated in
[2]. We consider here the action of such a force on a flat plate
boundary layer up to Re=9*10^5 and the flow around a NACA-0017-like
hydrofoil with Re<8*10^4. The experiments were carried out in a
saltwater facility and accompanied by flow visualizations in an open
channel with sodium hydroxide as the working fluid.

>From the boundary layer equations with the Lorentz-force term one gains
a characteristic parameter Z (Tsinober--Shtern parameter [1]) describing
the ratio of electromagnetic to viscous forces. If this parameter equals
one, the boundary layer equations have a solution with an exponential
flow profile similar to the asymptotic suction profile. A considerable
transition delay and therefore drastic drag reduction should be expected
from such a boundary layer [3], because the exponential profile has
proven to be much more stable than the Blasius one. Force balance
measurements on a flat plate show indeed the reduction of total drag by
more than 80\% (see fig. 2). However, this drag reduction is due to the
momentum added to the flow by the body force. The skin friction on the
contrary is even slightly increased, as can be concluded from the
velocity profiles in fig. 2. The reason for this behavior
lies in the real force distribution and probably the high turbulence level
of the environment. It is ...

  • Lecture (Conference)
    Proceedings of the 11th European Drag Reduction Working Meeting, Prague, Sept. 15-17 1999, pp.84-85
  • Contribution to proceedings
    Proceedings of the 11th European Drag Reduction Working Meeting, Prague, Sept. 15-17 1999, pp.84-85

Permalink: https://www.hzdr.de/publications/Publ-1553
Publ.-Id: 1553


[Re(NBH2SBH3)(Me2PhP)(Et2dtc)]2 - A novel rhenium dimer with the unusual bridging (NBH2SBH3)4- ligand

Abram, U.


The title compound is formed during the reaction of [ReN(Me2PhP)(Et2dtc)2] (Me2PhP = dimethylphenylphosphine, Et2dtc- = diethyldithiocarbamate) with excess BH3 in tetrahydrofurane. Two ReV atoms are linked by two (NBH2SBH3)4- units which act as three-dentate ligand via N, S and H forming an 8-membered metallacycle with additional co-ordination of a hydrido H atom trans to the nitrogen atom. The ReN multiple bond length is 1.70(1) Å which is only slightly longer than in the starting compound [ReN(Me2PhP)(Et2dtc)2] (1.666(6) Å).

Keywords: Keywords: Rhenium complexes; Nitrido bridges; Diborinyl sulfide; Crystal structure

  • Communication in Inorg. Chem. Communications

Permalink: https://www.hzdr.de/publications/Publ-1550
Publ.-Id: 1550


Two-phase flow in the anode chamber of alkaline chloride electrolysis cells

Schneider, C.

In membrane electrolysis cells a layer of spherical foam was found grow-ing with increasing performance. At the top a transition to cell foam oc-curs. Near the cell bottom the boundary layer of gas fraction and velocity at the electrode was measured. The velocity boundary layer changes from laminar to turbulent.

Keywords: gas fraction distribution; foam; bubble size; liquid circulation; hydrogen peroxide decomposition

  • Lecture (Conference)
    ECCE 2 - Second European Congress of Chemical Engineering - Montpellier 05.-07.10.1999, paper CDROM 09170010.pdf.
  • Contribution to proceedings
    ECCE 2 - Second European Congress of Chemical Engineering - Montpellier 05.-07.10.1999, paper CDROM 09170010.pdf.

Permalink: https://www.hzdr.de/publications/Publ-1549
Publ.-Id: 1549


Sources of Radiation Dose to Technologists by FDG-PET

Linemann, H.; Will, E.; Beuthien-Baumann, B.; Wittmüß, A.; Schröder, H.; Kutzner, H.; Hauptmann, A.

Introduction:
The aim of this study was to identify the main sources of radiation doses to technologists during PET studies to minimize the radiation exposure in routine F-18-FDG scanning.

Materials and methods:
The radiation exposure, personal dose and hand dose to technologists were measured during preparation and performance of F-18-FDG-PET scans.
The PET studies included dynamic brain scans with manual blood sampling, as well as heart and whole body scans without blood sampling. The injected activities varied between 260 and 370 MBq.
Transport of radiopharmaceutical (max. 7 GBq) in a lead container, 3 cm wall thickness. Preparation of the syringes in a lead box with window of 3 cm lead-equivalent. During injection the syringes were handled with a special pair of tongs. The syringe was shielded with an 8 mm tungsten wall. To protect the technologist from radiation emitted by the patient during manual blood sampling a movable radiation shield (2 cm lead) was placed between patient and technologist.

Results and conclusions:
Personal dose [µSv] at: syringe preparation - <=1; injection - 3; blood sampling - 28; patient handling - 15. Hand dose (rings) [µSv]: 27 left, 13 right. Hand dose (tapes) [µSv]: 710 left and right.
Assuming 13 PET studies/week and 52 working weeks/year the personal dose may lead to about 10 mSv/a.
Our measurements indicate that the maximal allowed hand dose per year will be reached after preparations of 500 syringes. Therefore, in PET facilities with a high patient throughput an automatic filling device has to be used.

Keywords: personal dose; hand dose; radiation exposure; FDG; PET; Positronen emissions tomography

  • Poster
    1999 ECAT USERS MEETING, 21-24. 4. 1999 in Amsterdam

Permalink: https://www.hzdr.de/publications/Publ-1548
Publ.-Id: 1548


No-carrier-added 11C-labelling of benzenoid compounds in ring positions by condensation of nitro-[11C]methane with pyrylium salts

Mäding, P.; Steinbach, J.; Johannsen, B.

A new synthesis is described for three n.c.a. nitro-[1-11C]benzenes 3a-c by condensation of nitro-[11C]methane (1) with the appropriate pyrylium salts 2a-c in the presence of a base such as t-BuOK in t-BuOH. For synthesizing 4-nitro-[4-11C]anisole (3a), tetrabutylammonium fluoride was successfully used as an auxiliary base. The best results were obtained in the synthesis of 3a. The conversion of 1 with 4-methoxypyrylium perchlorate (2a) yielded 3a of a radiochemical purity of up to 82 % and a mean specific radioactivity of 30 GBq/µmol (0.8 Ci/µmol) within 20 min. Related to 1, the reproducible radiochemical yields of 3a are in the range of 77 ± 5 % (decay-corrected). 2,6-Dimethyl-4-methoxy-nitro-[1-11C]benzene (3b) was prepared by reaction of 1 with 2,6-dimethyl-4-methoxypyrylium perchlorate (2b) in radiochemical yields of about 37 % (decay-corrected) within 10 min. 2-Nitro-[2-11C]mesitylene (3c) was obtained by condensation of 1 with 2,4,6-trimethylpyrylium tetrafluoroborate (2c) in radiochemical yields of about 29 % (decay-corrected) within 20 min. 13C/11C Co-labelling experiments were carried out in order to confirm the identity of 3a-c and the position of the label.

Keywords: 11C-ring labelling; nitro-[11C]methane; 4-nitro-[4-11C]anisole; 2,6-dimethyl-4-methoxy-nitro-[1-11C]benzene; 2-nitro-[2-11C]mesitylene

  • J. Labelled Cpd. Radiopharm. 43 (2000) 565-583

Permalink: https://www.hzdr.de/publications/Publ-1547
Publ.-Id: 1547


High-purity niobium for neutron activation detectors

Mönch, I.; Stephan, I.; Köthe, A.

High-purity niobium has successfully been used as neutron detector material in advanced neutron dosimetry. Reliable and accurate neutron dosimetry measurements are needed to control the neutron load of the reactor pressure vessel (RPV) during its operation. Neutrons-irradiation of the RPV material causes an embrittlement of the ferritic steel. The effect is highly safety-relevant and must, thus, be monitored. It is standard to use a set of several materials with different neutron activation or spallation reactions. An cases of the niobium detectors the nuclear reaction one makes use of 93Nb(n,n`)93mNb reaction. It is specially favourable because the energy dependence of this reaction is similar to the energy dependence of the damage function of the RPV material. Furthermore, the half-life is long (16.1 years) and results in a nearly constant weighting over the reactor cycle. Therefore, the decay correction is only small in comparison with other detectors.
Niobium of low purity is not appropriate for this purpose. Impurities can affect additional activation reactions. Especially detrimental is tantalum. The neutron capture of 181Ta leads to 182Ta resulting in high energy gamma lines (1121,1122 keV) and added excitation of the detected 16 and 18 keV niobium lines. The correction of these effects is difficult and yields additional errors.
The requirements of the purity are strict: a good niobium detector must not have a Ta concentration of more than 1 ppm.
The niobium was produced by a technology which consists of an electrolytic refining, melting processes and mechanical treatment. In the cathodic niobium (electrolysis conditions: T = 750°C, j=0.4 mA/mm²) the so-called "problematic element" Ta could not be detected by instrumental neutron-activation analysis (cTa <<1 at.ppm).
With the niobium produced in this way, the neutron fluence at the VVER-type RPVs of the nuclear power plants in Greifswald (Germany), Rovno, and Balakovo (Russia) were determined. Int ...

Keywords: High purity niobium; neutron detector; electrolytic refining

  • Lecture (Conference)
    Tagung Ultra High Purity Base 1999 Metals, Sendai, Japan
  • Material Transactions JIM Vol. 41, 1 (2000) 1ff

Permalink: https://www.hzdr.de/publications/Publ-1545
Publ.-Id: 1545


Euroconference and NEA Workshop Actinide-XAS-98

Reich, T.

Euroconference and NEA Workshop Actinide-XAS-98

  • Contribution to external collection
    ESRF Newsletter

Permalink: https://www.hzdr.de/publications/Publ-1542
Publ.-Id: 1542


Structures of Iodophenyltellurium(II) and Diiododi-(beta-naphtyl)tellurium(IV)

Schulz Lang, E.; Fernandes, R. M. J.; Silveira, E. T.; Abram, U.; Vazquez-Lopez, E. M.

Structures of Iodophenyltellurium(II) and Diiododi-(b-naphtyl-tellurium(IV)

Abstract. The reactions between diphenyl ditelluride, (PhTe)2, or di(b-naphtyl)-ditelluride, (b-naphtylTe)2, with equivalent amounts of iodine have been reinvestigated and the crystal and molecular structures of iodophenyltellurium(II), (PhTeI)4, and diiododi-(b-naphtyl)-tellurium(IV), (b-naphtyl)2TeI2, have been determined.
The structure of iodophenyltellurium(II) (space group Cc, a = 13.850(5) Å, b = 13.852(3) Å, c = 16.494(6) Å and b = 101.69(2)°, Z = 4) is built up by four PhTeI units which are linked by weak Te-Te interactions with Te-Te distances between 3.152(5) Å and 3.182(4) Å. The angles between the tellurium atoms are approximately 90° giving an almost perfect square. Long range secondary bonds (Te ---- I: about 4.2 Å) link the tetrameric units to give an infinite two-dimensional network.
Iodo(b-naphtyl)tellurium(II) is less stable than the phenyl derivative. Solutions of this compound decompose under formation of elemental tellurium and (b-naphtyl)2TeI2. (b-Naphtyl)2TeI2 crystallises in the monoclinic space group C 2/c (a = 21.198(6) Å, b = 5.8921(8) Å, c = 16.651(5) Å, b = 114.77(2)°). The tellurium atom is situated on a two-fold crystallographic axis and Te-I and Te-C bond lengths of 2.899(1) and 2.108(7) Å have been determined.



  • Zeitschrift für anorganische und allgemeine Chemie, 1999, 625, 1401-1404

Permalink: https://www.hzdr.de/publications/Publ-1540
Publ.-Id: 1540


Complexation and phase transfer of perrhenate and pertechnetate with guanidium hosts

Stephan, H.; Spies, H.; Berger, R.; Johannsen, B.; Schmidtchen, F. P.

Noncovalent binding of pertechnetate may be of considerable interest as a new approach to labelling organic compounds with technetium without any reduction step, and for removal of pertechnetate as an environmental contaminant. Effective and selective complexation of pertechnetate should be realisable on the basis of molecular assembled supramolecular receptors that can provide multi-point fixation of tetrahedral anion pertechnetate as shown in the figure.

This paper reports on complexation experiments of pertechnetate and its nonradioactive congener perrhenate using different guanidinium compounds. The characterisation of these Tc(VII) and Re(VII) complexes are supported by X-ray crystal structures, TLC, infrared and NMR spectra. Liquid-liquid extraction studies are performed in order to monitor the influence of competition anions on phase transfer and to evaluate the stoichiometry of the complexes extracted. Lipophilicity and ionisation properties of guanidinium hosts and their Tc(VII)/Re(VII) complexes are determined by RP-HPLC. Molecular modeling calculations are used for the interpretation of the experimental results.

  • Poster
    XXIV. International Symposium on Macrocyclic Chemistry, 18-23 July 1999, Barcelona
  • Contribution to proceedings
    XXIV. International Symposium on Macrocyclic Chemistry, 18-23 July 1999, Barcelona

Permalink: https://www.hzdr.de/publications/Publ-1539
Publ.-Id: 1539


Cora - a new control program for the roma detection system

Taut, S.

A new computer program has been developed for the control of the GSI Rotating Wheel Multi Detector Apparatus (ROMA) running under the Windows 95 and Windows NT 4.0 operating systems. It can be fitted to a lot of detection tasks in a highly flexible way.

The ROMA apparatus [1] has been used successfully for a lot of chemical investiga-tions of transactinide elements. In preparation of our seaborgium experiment at GSI in sum-mer 1998 [2] we developed a new control program. This was necessary because the old control code was running on an ATARI computer. In case of a damage of this computer, there would not have been the possibility of a replacement, which could possibly cancel the experiment.
The new program was designed to fulfill our special experimental requirements. A second feature is its support of the usual working conditions in a long running beam time. That means, persons without a deep understanding of a computer should be able to use this program without any difficulties, even if the programmer is not available. Thirdly, it should be highly flexible in order to adapt it to new experimental demands. Finally, the program should be to a great extent independent of the experiment hardware in order to be usable for similar apparatuses.
The program is written entire-ly in the C++ language using the Borland C++ Builder 1.0 programming environment based on the object oriented Virtual Component Library.

The program has to carry out the following tasks:

· control of the ROMA wheel movements according to the actual experiment;
· enabling and disabling the nuclear spectros-copy data acquisition;
· sending information about the actual ROMA status to the data acquisition hardware;
· processing requests of the acquisition hardware (e. g. switching in "daughter mode" [3]);
· processing user input (e. g. experiment and wheel setup dialog boxes).

The program is a Microsoft Windows applicatio ...

  • Poster
    1. Internationale Conference on the Chemistry and Physics of the Transactinide Elements TAN 99

Permalink: https://www.hzdr.de/publications/Publ-1538
Publ.-Id: 1538


Visualization of cavitating liquid flow behind fast acting valve

Dudlik, A.; Prasser, H.-M.; Schlüter, S.

The paper presents high speed measurements of the transient void fraction distribution in the cavitating flow behind fast acting butterfly valves. A new electrode mesh sensor with a time resolution of 1024 frames per second was used. As a result, a new method to avoid cavitational water hammers was found.

Keywords: Plant safety; pipelines; water hammers; cavitation collapses; fast two-phase flow visualisation

  • Poster
    ECCE 2 - Second European Congress of Chemical Engineering - Montpellier 05.-07.10.1999, paper CDROM 11270003.pdf.
  • Contribution to proceedings
    ECCE 2 - Second European Congress of Chemical Engineering - Montpellier 05.-07.10.1999, paper CDROM 11270003.pdf.

Permalink: https://www.hzdr.de/publications/Publ-1537
Publ.-Id: 1537


Measurement of Gas Fraction, Gas Velocity and Volume Flow by Electrode Mesh Sensors

Prasser, H.-M.

A new wire-mesh sensor for gas-liquid flows is presented. Air-water mixtures in a vertical pipe were studied in a wide range of superficial ve-locities. Gas fraction and gas velocity profiles as well as a high resolution imaging of the flow structure are obtained. A volume flow rate measure-ment is feasible.

Keywords: gas-liquid flow; flow visualisation; gas fraction; gas velocity; gas flow rate

  • Lecture (Conference)
    ECCE 2 - Second European Congress of Chemical Engineering - Montpellier 05.-07.10.1999, paper CDROM 11280001.pdf.
  • Contribution to proceedings
    ECCE 2 - Second European Congress of Chemical Engineering - Montpellier 05.-07.10.1999, paper CDROM 11280001.pdf.

Permalink: https://www.hzdr.de/publications/Publ-1536
Publ.-Id: 1536


Void fraction measurement in foams using needle shaped conductivity probes

Kern, T.

Needle Shaped Conductivity Probes have been applied to measure the properties of aqueous alcohol foams. Simultaneous usage of gamma densitometry and video imaging should allow a calibration and prove the values of the probe. The results show that the conductivity probes are able to measure in the foam zone as well as in the bubbly flow whereas the geometry of the foam causes some problems to detect reliably the foam bubbles.

Keywords: Conductivity Probes; Foam; Void Fraction; Bubble Size; Coalescence

  • Poster
    The Second European Congress on Chemical Engineering: "Chemical Engineering for competitiveness and employment in process industries", 5-7 October 1999, Montpellier, France, proceedings on CD-ROM, 09010004.pdf.
  • Contribution to proceedings
    The Second European Congress on Chemical Engineering: "Chemical Engineering for competitiveness and employment in process industries", 5-7 October 1999, Montpellier, France, proceedings on CD-ROM, 09010004.pdf.

Permalink: https://www.hzdr.de/publications/Publ-1535
Publ.-Id: 1535


Synthesis of [1-11C]phenol

Mäding, P.; Steinbach, J.

The synthesis of n.c.a. [1-11C]phenol (3) which is a further important aromatic 11C unit for potential PET radiotracers is decribed for the first time. [1-11C]aniline (1) was diazotized and the [1-11C]benzenediazonium bromide (2) formed was concentrated in situ to give 3. Before diazotization, 1 had to be purified twice by means of an adsorber resin and a cation exchange resin. Starting from the purified 1, 3 was obtained in a radiochemical purity of about 79 % within 10 min. Related to crude 1 from the one-pot process, thereproducible radiochemical yield of 3 was about 16 % (decay-corrected). 13C/11C Co-labelling experiments were carried out in order to confirm the identity of 3 and the position of the label.

Keywords: PET; 11C-ring labelling; diazotization; [1-11C]aniline; [1-11C]phenol

  • J. Labelled Cpd. Radiopharm. 43 (2000) 557-563

Permalink: https://www.hzdr.de/publications/Publ-1534
Publ.-Id: 1534


Electromagnetic Control of Flow Separation

Weier, T.; Fey, U.; Mutschke, G.; Gerbeth, G.; Lammers, G.; Lielausis, O.

The flow of electrically conducting fluids like sea water around bodies can be controlled by electromagnetic forces. These forces may be generated by a suitably chosen arrangement of permanent magnets and electrodes on the surface of the body.

We consider surface parallel Lorentz-forces acting in streamwise direction.This configuration allows to prevent the boundary layer from separation, resulting in higher lift and/or lower form drag of the body.Experimental results on the flow around a circular cylinder, an inclined plate and a hydrofoil are presented for Reynolds numbers up to 10**5. In the caseof the cylinder both steady and time-periodic forcing are applied.

The experiments were carried out in an open channel with sodium hydroxide as the working fluid and in a sea water facility. Flow visualizations showing serious separation delays will be presented together with values for drag and lift in different configurations.

Direct numerical simulations at low Reynolds numbers confirm the physical tendencies of the experiments.

Keywords: body force; flow control; flow separation; MHD; boundary layer

  • Contribution to proceedings
    2nd International Conference on Marine Electromagnetics, July 5--7, 1999, p. 197-205

Permalink: https://www.hzdr.de/publications/Publ-1533
Publ.-Id: 1533


A Benchmark for Coupled 3D Neutron Kinetics/Thermohydraulics System Codes - Main Steam Header Break in a NPP with VVER-440 Reactor

Kliem, S.; Danilin, S.; Kyrki-Rajamäki, R.; Hadek, J.; Kereszturi, A.; Siltanen, P.

Recently 3D neutron kinetics core models have been coupled to advanced thermohydraulics system codes. These coupled codes can be used for the analysis of the whole reactor system. In the framework of the international "Atomic Energy Research" (AER) association on VVER Reactor Physics and Reactor Safety, a benchmark for these code systems was defined. The reference reactor is the Russian VVER-440. The response of the reactor core to a main steam header break should be investigated. Solutions were received from the following five organizations: Kurchatov Institute Moscow (Russia), VTT Energy Espoo (Finland), Nuclear Research Institute Rez (Czech Republic), KFKI AEKI Budapest (Hungary) and Forschungszentrum Rossendorf (Germany). The paper presents an overview of the results of the benchmark. A good agreement in the thermohydraulic behaviour can be observed, the main differences between the solutions arise from the use of different nuclear data.

  • Lecture (Conference)
    Proc. International Conference on Mathematics and Computation, Reactor Physics and Environmental Analysis in Nuclear Applications (MC '99), vol. 1, pp. 359-368, Senda Editorial, S.A., Madrid (Spain)
  • Contribution to proceedings
    Proc. International Conference on Mathematics and Computation, Reactor Physics and Environmental Analysis in Nuclear Applications (MC '99), vol. 1, pp. 359-368, Senda Editorial, S.A., Madrid (Spain)

Permalink: https://www.hzdr.de/publications/Publ-1532
Publ.-Id: 1532


Efficient phase transfer of pertechnetate with bicyclic guanidinium compounds

Stephan, H.; Berger, R.; Spies, H.; Johannsen, B.; Schmidtchen, F.-P.

Extraction of pertechnetate with bicyclic guanidinium compounds has been studied in the system KTcO4-buffer-H2O/ligand-trichloromethane. Extraction data of guanidinium ligands have been compared with trialkylmethylammonium (Aliquat 336), tetraphenylphosphonium and tetraphenylarsonium chloride. The lipophilicity of extractants investigated was determined by RP-HPLC. The efficiency of pertechnetate extraction correlates with the lipophilicity of the guanidinium compounds. 1:1 complex formation in the organic phase was observed. The influence of hydroxide, chloride and bicarbonate on the pertechnetate extraction has been investigated. Pertechnetate is extracted with great preference over OH-, Cl- and HCO3-.

  • Journal of Radioanalytical and Nuclear Chemistry 242 (2) (1999) 399-403

Permalink: https://www.hzdr.de/publications/Publ-1531
Publ.-Id: 1531


Tetraphenylphosphonium tetrakis(1-methyl-1,2,3,4-tetrazole-5-thiolato-S)- aurate(III) hemihydrate

Schulz Lang, E.; Dahmer, M.; Abram, U.

The tetraphenylphosphonium salt of tetra(1-methyl-1,2,3,4-tetrazole-5-thiolato)aurate(III) crystallizes as H2O solvate in the monoclinic space group C2/c with the gold atom situated on an inversion centre. The tetrazole rings are arranged almost orthogonally to the square coordination sphere. Au-S-C angles of 106.16(11) and 107.14(12)° have been found.

  • Acta Crystallographica C (1999), C55, 854-856

Permalink: https://www.hzdr.de/publications/Publ-1529
Publ.-Id: 1529


Entwicklung von Zweiphasenmeßtechnik für vergleichende Untersuchungen zur Beschreibung von transienten Strömungen in Rohrleitungen

Prasser, H.-M.; Böttger, A.; Zschau, J.

Für die Untersuchung von transienten Zweiphasenströmungen in Rohrleitungen, bzw. Rohrleitungssegmenten wurden im Fraunhofer-Institut für Umwelt, Sicherheits- und Energietechnik e.V. Oberhausen (UMSICHT) eine Druckstoßanlage als Freiluftanlage errichtet. Diese Anlage besteht aus zwei ca. 200 m langen Rohrleitungen mit den Nennweiten DN50 und DN100. Aufgabe des FZR war die Instrumentierung der Anlage mit Zweiphasenmeßtechnik sowie die Mitwirkung bei den experimentellen Untersuchungen und deren Interpretation. Die Anlage wurde vom FZR mit 16 nadelförmigen Leitfähigkeitssonden, einem neuartigen Gittersensor-Meßsystem und Ultraschall-Aufnehmern ausgerüstet. Mit den Gittersensoren, die 1024 Messungen pro Sekunde ermöglichten, wurde die bisher zugängliche Zeitauflösung hinsichtlich der Erfassung des gesamten Strömungsquerschnitts um etwa eine Größenordnung überboten. Die hinter einer schnellschließenden Klappe auftretenden großräumige Kavitationsblasen wurden visualisiert, deren maximale Ausdehnung in Strömungsrichtung mit zunehmender Strömungsgeschwindigkeit und Rohrleitungslänge anwächst. Innerhalb der Kavitationsblase liegt kurze Zeit nach dem Schließen der Armatur eine geschichtete Strömung vor. Die durch den Gegendruck abgebremste und erneut in Richtung auf die Armatur beschleunigte Flüssigkeitssäule prallt als Schwall auf die geschlossene Armatur, wodurch der Kavitationsschlag entsteht. Nachfolgend werden durch Reflexionen der Druckwelle weitere Kavitationsblasen erzeugt. In der Klappe tritt während des Schließvorgangs Kavitation auf. Die charakteristischen Dampfgehaltsverteilungen sind stark transient und weisen ausgeprägte räumliche Verteilungen auf. Auch vor der schnellschließenden Armatur treten unter bestimmten Bedingungen Kavitationsblasen auf, wenn die anfängliche Druckwelle vom Anfang der Rohrleitung als Entspannungswelle reflektiert wird und zurückkehrt.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-233 Februar 1999 ISSN 1437-322X, Abschlußbericht zum Vorhaben 11ZF9504/1
    ISSN: 1437-322X

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Permalink: https://www.hzdr.de/publications/Publ-1527
Publ.-Id: 1527


Physico-chemical characterization of Seaborgium as oxide hydroxide

Hübener, S.; Brüchle, W.; Dressler, R.; Eichler, B.; Gäggeler, H. W.; Grantz, M.; Heyne, H.; Jäger, E.; Jost, D. T.; Kirbach, U. u. a.


The physico-chemical characterization of seaborgium as oxide hydroxide, performed in 1998 at the GSI accelerator UNILAC, continues earlier gas chromatographic studies of seabor-gium oxychlorides [1, 2]. In our former studies seaborgium behaved like a typical group 6 element despite the relativistic effects, which are increasing with the nuclear charge and cause unexpected chemical properties of the lighter transactinide elements rutherfordium and dubnium [3, 4]. To characterize seaborgium its properties have to be compared with those of other elements, first of all its homologues molybdenum and tungsten. The clear gra-dation of their chemical properties favors the oxides of the group 6 elements for studies of the influence of relativistic effects on the chemical properties of seaborgium. All the more as gas chromatographic studies of oxides or oxide hydroxides, respectively, provide high selec-tivity with regard to the lighter transactinides and interfering actinides. But on the other hand, the surface reactions dissociative adsorption and associative desorption governing the reac-tion ...

  • Lecture (Conference)
    I. Intern. Conference in the Chemistry and Physics of the Transactinide Elements TAV 99

Permalink: https://www.hzdr.de/publications/Publ-1526
Publ.-Id: 1526


Biologische Charakterisierung von 18F-markierten Neurotensinderivaten zur Tumordarstellung mit der Positronen-Emissions-Tomografie.

Bergmann, R.; Rodig, H.; Brust, P.; Scheunemann, M.; Mäding, P.; Steinbach, J.; Iterbeke, K.; Tourwe, D.; Johannsen, B.

Mit dem bildgebenden Verfahren der Positronen-Emissions Tomographie (PET) können Transportprozesse, Enzymreaktionen und Rezeptoren in vivo, räumlich, zeitlich und quantitativ mit großer Sensitivität erfaßt werden. Entsprechend werden auch diagnostische Fragestellungen in der Medizin gelöst, die Veränderungen der genannten biochemischen Prozesse beinhalten. Eine Voraussetzung sind mit Positronenstrahlern z.B. mit 18F (T1/2=110 min) oder 11C (T1/2=20 min) markierte Radiotracer, die hochspezifisch mit biologischen Bin-dungspartnern reagieren und eine geeignete Biokinetik besitzen. Zu solchen Radiotracern gehören auch ra-dioaktiv markierte Peptide und deren Derivate. In klinischen Untersuchungen werden bereits radioaktiv mar-kierte Somatostatinanaloga zur Tumordetektion eingesetzt (1). Ein ähnliches Potential besitzt auch Neuro-tensin (NT). Die G-Protein abhängigen Membranrezeptoren für NT werden auch in verschiedenen Tumoren, z.B. kleinzelligen Lungenkarzinomen, Pankreaskarzinomen u.a., überexprimiert (2). Ziel der Arbeiten ist es, einen Radiotracer zu entwickeln, der die in vivo Darstellung solcher Tumore mit PET ermöglicht. Dazu sind NT-Agonisten erforderlich, die durch Bindung und durch Internalisierung in der Targetregion angereichert werden, gleichzeitig aber auch schnell aus dem Blut eliminiert werden.
Die erstmalig mit 4-[18F]Fluorsuccinimidylbenzoat an der alpha-Aminogruppe des N-Terminus 18F-markierten lysinfreien Peptide 4-[18F]FB-NT(8-13) und 4-[18F]FB-[Arg8Y(CH2NH)Arg9]NT(8-13) (4) wurden in vitro auf Rezeptoraffinität, Bindung an NT-Rezeptoren in Hirnschnitten und in vivo mit PET und durch Messung der Verteilung in Ratten charakterisiert.
Zur Affinitätsbestimmung in vitro wurden die radioaktiv markierten Peptide eine Stunde bei 37°C mit den stabil NTR1-Rezeptor exprimierenden HT-29 Zellen inkubiert. Beide Peptide binden an diesen Rezeptor. Für 4-[18F]FB-NT(8-13) wurde ein KD von 5,1 nM ermittelt. In Simultanuntersuchungen mit [3H]NT korreliert deren Rez ...

Keywords: Peptide; Positron Emission Tomography; Tumour

  • Poster
    4. Deutsches Peptidsymposium, Leipzig, 21.3. - 24.3.1999,

Permalink: https://www.hzdr.de/publications/Publ-1524
Publ.-Id: 1524


Long-distance transport of radionuclides between PET cyclotron and PET radiochemistry

Preusche, S.; Füchtner, F.; Steinbach, J.; Zessin, J.; Krug, H.; Neumann, W.

The Rossendorf PET Center has a special feature: its PET cyclotron and the radiochemical laboratories are 500 metres away from each other. The distance is bridged by our radionuclide transport system (RATS).
Details of RATS such as layout, technical parameters, control system, radiation protection and our experience in long-distance transport of radionuclides, are indicated below.

Keywords: RATS

  • Appl. Rad. Isot. 51 (1999) 625-630

Permalink: https://www.hzdr.de/publications/Publ-1523
Publ.-Id: 1523


[Re{NB(C6F5)3}(Et2dtc)2]2 - Dimerization as a Consequence of the Formation of a Nitrido Bridge

Abram, U.

Abstract. The title compound is formed from the five-coordinate [ReN(Et2dtc)2] upon reaction with B(C6F5)3. As a consequence of the formation of a nitrido bridge between Re and B the structural trans influence of the nitrido ligand decreases and its trans position which is not occupied in the edduct becomes available for co-ordination. The dimer is built up by two [Re{NB(C6F5)3}(Et2dtc)2] units which are linked by weak bonds between the metal and each one sulphur atom of the neighbouring unit (Re-S: 2.856(6) and 2.835(6) Å, respectively).
Keywords: Rhenium complexes, Nitrido bridges, Crystal structure, Dimerization

Keywords: Rhenium complexes; Nitrido bridges; Crystal structure; Dimerization

  • Communication in Zeitschrift für anorganische und allgemeine Chemie 1999, 625, 839-841

Permalink: https://www.hzdr.de/publications/Publ-1522
Publ.-Id: 1522


Basic aqueous chemistry of [M(OH2)3(CO)3]+(M=Re,Tc) directed towards radiopharmaceutical application

Alberto, R.; Schibli, R.; Waibl, R.; Abram, U.; Schubiger, P. A.


Abstract
A review on the synthesis and properties of the organometallic aqua-ion [M(OH2)3(CO)3]+ (M = Re, 99Tc, 99mTc), as relevant for radiopharmaceutical application, is presented. These important starting compounds can be prepared quantitatively a) on the no carrier added level (99mTc) in water or b) in organic solvents (Re, 99Tc) at atmospheric pressure in a short time and from [MO4]-. The main characteristics of these carbonyl complexes are the high substitution stability of the three CO ligands and the substitution lability of the coordinated water molecules. [M(OH2)3(CO)3]+ can be considered as a "semi aquo-ion". On the macroscopic level, upon titration with OH-, hydroxo-bridged oligomers have been isolated and characterized. The formation of hydroxo-bridged complexes is a consequence of the considerable Broenstedt acidity of [M(OH2)3(CO)3]+, whereas on the no carrier added level (n.c.a.) no such behavior was observed. Conditions and products of the water exchange by imidazole (im) and derivatives thereof (histamine, histidine) will be presented. The different mononuclear complexes with these ligands are of extraordinary inertness, which is the base for a potential application in biology and nuclear medicine. Finally, as a base for bioorganometallic chemistry, the adoption of the results from basic coordination chemistry to the labeling of biomolecules with an organometallic moiety will be exemplified with a selected penta-peptide and a recombinant single chain fragment.
Keywords: Tc-carbonyls, Tc-peptide complexes, scFv, cancer diagnosis, radiopharmacy

  • Coord. Chem. Rev. 190-192 (1999) 901-919

Permalink: https://www.hzdr.de/publications/Publ-1521
Publ.-Id: 1521


Synthese, Charakterisierung und Struktur von Carbonyl- und Hydrido-Isocyanatokomplexen des Rutheniums

Bonfada, E.; Maichle-Mößmer, C.; Strähle, J.; Abram, U.


Synthesis, Characterization and Structure of Carbonyl and Hydrido Isocyanato Complexes of Ruthenium

Abstract. [Ru(CO)H(NCO)(PPh2Me)3] is formed during the reaction between [RuCl3(PPh2Me)3] and NaOCN in EtOH. The compound crystallizes in the monoclinic space group P21/n (a=1256.4(4), b=1487.2(2), c=1993.5(5) pm, b=97.28(1)°, Z=4). The distorted octahedral coordination sphere of RuII contains the phosphine ligands in meridional arrangement, their P atoms forming a plane together with the hydride ligand.
The reaction of [RuCl3(PPh3)2] with NaOCN in EtOH yields [Ru(NCO)-(CO)(CH3COO)-(PPh3)2] with trans coordinated Ph3P ligands.
The formation of hydrido, carbonyl and acetato ligands are due to the reaction of the transition metal with the solvent ethanol.





  • Zeitschrift für anorganische und allgemeine Chemie 1999, 625, 1327-1330

Permalink: https://www.hzdr.de/publications/Publ-1520
Publ.-Id: 1520


Raman investigation of lattice defects in the CoSi2 synthesis using focused ion beam implantation

Teichert, J.; Hobert, H.; Bischoff, L.; Hausmann, S.

CoSi2 layers were produced by 70 keV Co focused ion implantation into (111)Si. Within a comparative study the CoSi2 layer quality and implantation damage were investigated as a function of pixel dwell-time and substrate temperature. Irradiation damage measurements were done by micro-Raman analysis. The results suggest that the dwell-time dependence of the CoSi2 layer formation - continuous layers for short and disrupted for long dwell-time - is caused by an adequate change from crystalline to amorphous silicon.

Keywords: Focused ion beam; Raman scattering; Ion implantation; Damage; CoSi2

  • Contribution to proceedings
    European Workshop Materials for Advanced Metallization, 8.-10. März, Ostende, Belgien
  • Microelectronic Engineering 50 (2000) 187-192

Permalink: https://www.hzdr.de/publications/Publ-1519
Publ.-Id: 1519


Integral representation of the RPA correlation energy

Dönau, F.; Almehed, D.; Nazmitdinov, R.

Using the spectral function F'(z)/F(z) the RPA correlation energy and other properties of a finite system can be written as a contour integral in a compact way. This yields a transparent expression and reduces drastically the numerical efforts for obtaining reliable values. The method applied to pairing vibrations in rotating nuclei as an illustrative example.

Keywords: Random Phase Approximation; Hatree-Fock

  • Physics Review Letters 83, 1999, 280-3

Permalink: https://www.hzdr.de/publications/Publ-1518
Publ.-Id: 1518


Kolloidchemische Untersuchung an Wasser aus dem Hauptwässerungsstollen des Freiberger Bergbaureviers

Richter, W.; Zänker, H.; Brendler, V.

Der Rothschönberger Stolln leitet den Hauptteil der Grubenwässer des stillgelegten Freiberger Bergbaureviers in die Triebisch, einem Nebenfluß der Elbe. Das Ziel unserer Untersuchungen waren Aussagen über den kolloidalen bzw. kolloidgebundenen Anteil der wichtigsten toxischen Elemente am Mundloch des Stollens.

Es wurden Wasserproben in den Monaten Februar, April, August, Oktober sowie Dezember 1998 genommen. Nach Vor-Ort-Analysen (T, pH, O2-Gehalt, Redox-Potential und Leitfähigkeit) wurden die Proben im Labor kolloidchemisch mit den folgenden Techniken untersucht: Filtration bzw. Ultrafiltration, Zentrifugation, Sedimentation, Photonenkorrelationsspektroskopie (PCS) und Rastereletronenmikroskopie (REM) mit energiedisperser Röntgenanalyse (EDX). Die chemischen Analysen erfolgten mittels induktiv gekoppelter Plasma-Massenspektroskopie (ICP-MS), Atomabsorptionsspektroskopie (AAS) sowie Ionenchromatographie (IC). Von der Arbeitsgruppe J. Thieme (Universität Göttingen, Einrichtung Röntgenphysik) wurden parallel röntgenmikroskopische Untersuchungen mittels Synchrotronstrahlung durchgeführt.

Die PCS-Messungen an den Wasserproben ergaben, daß im Wasser des Rothschönberger Stollns Kolloidpartikel im Bereich von 100 bis 300 nm mit einem Maximum bei ca. 200 nm anwesend sind. Ihre Konzentration beträgt etwa 1 mg/l. Auf REM-Aufnahmen an beladenen Kernspurfiltern sind diese Partikel zu erkennen. Die Abnahme der Streulichtintensität bei den PCS-Messungen und der chemischen Gehalte in den Zentrifugaten nach der Parallel-Zentrifugation mit zunehmender Zentrifugalbeschleunigung ergeben, daß es zwei Gruppen von chemischen Elementen gibt. Während die Elemente Fe, Al, Pb, As, La, Y und Cu mit wachsender Zentrifugalbeschleunigung und beim Filtrieren mit sinkender Porenweite zunehmend abgeschieden werden, lassen sich alle übrigen der 25 mit ICP-MS/AAS analysierten Elemente nicht abzentrifugieren bzw. passieren alle Filter und Ultrafilter bis zu einer Porenweite von 3kD (ca. 1, ...

  • Lecture (Conference)
    5. Kolloquium des DFG Schwerpunktprogramms "Geochemische Prozesse..."

Permalink: https://www.hzdr.de/publications/Publ-1517
Publ.-Id: 1517


Elektromagnetische Grenzschichtkontrolle - Theorie und Numerik

Mutschke, G.; Avilov, V.; Gerbeth, G.

Im Rahmen des Verbundprojektes wurden theoretische Untersuchungen zur Modellierung der aus periodischen Anordnungen von alternierenden Magneten und Elektroden entstehenden wandnahen Lorentzkräfte bei Körperumströmungen in schwach-leitfähigen Fluiden durchgeführt. Hierbei konnte die Beschreibung der Lorentzkräfte für die klassische Konfiguration aus rechteckigen Magneten und Elektroden entschieden verbessert werden. Diese Modellierung war notwendige Voraussetzung für die Durchführung numerischer Simulationen von Platten- und Tragflügelumströmungen, für welche im Rahmen des Verbundprojektes Umströmungsexperimente an der HSVA durchgeführt wurden. Existierende Codes zur Berechnung turbulenter Umströmungen enthalten stets aus der Turbulenztheorie abgeleitete Wandfunktionen für den wandnahen Bereich. Diese können hier nicht verwendet werden, da die elektromagnetische Kraft gerade im wandnahen Bereich ihre Wirkung entfaltet. Deshalb wurde bewußt eine direkte numerische Simulation der Umströmung gewählt, obwohl diese zunächst auf relativ niedrige Reynolds-Zahlen beschränkt ist. Hierbei fand ein moderner Code mit spektralen Elementen Anwendung. Die Simulationen belegen, daß mit Hilfe der Grenzschichtkontrolle durch wandparallele Lorentzkräfte die Strömungsablösung an der Saugseite eines angestellten Ruders wirksam verzögert bzw. unterdrückt werden kann und damit eine erhebliche Auftriebsverbesserung erreicht wird.


  • Poster
    Statusseminar "Technische Anwendungen von Erkenntnissen der Nichtlinearen Dynamik", Frankfurt, 23./24.02.1999 Tagungsband. S. 201-204
  • Contribution to proceedings
    Statusseminar "Technische Anwendungen von Erkenntnissen der Nichtlinearen Dynamik", Frankfurt, 23./24.02.1999 Tagungsband. S. 201-204

Permalink: https://www.hzdr.de/publications/Publ-1515
Publ.-Id: 1515


Elektromagnetische Grenzschichtkontrolle - Experimente an der Hamburgischen Schiffbauversuchsanstalt

Fey, U.; Weier, T.; Lammers, G.


Im Rahmen des Verbundprojektes wurden Meßreihen zur Umströmung einer ebenen Platte und eines ruderförmigen Körpers durchgeführt. Die jeweils oberflächenparallele elektromagnetische Kraft entsteht durch die Kopplung äußerer elektrischer und magnetischer Felder, die von einer streifenartigen, wechselweisen Belegung der Körperoberflächen mit Permanentmagneten und Elektroden ausgehen. Aufgrund der Feldverteilungen ist die Kraftwirkung auf den Bereich der Strömungsgrenzschicht beschränkt. Es fanden Permanentmagnete mit einer Feldstärke im Bereich von 0.2 bis 0.4 Tesla Verwendung. Die Elektroden wurden mit Gleichstrom gespeist, bei maximalen mittleren Stromdichten von bis zu 0.5 A/cm2. Die Plattenexperimente zeigten eine deutliche Reduzierung des Strömungswiderstandes, die bei maximalem Elektrodenstrom bis zu 80% betrug. Dieses Ergebnis wird allerdings durch einen energetischen Aufwand erreicht, der die Einsparungen beim Reibungswiderstand überwiegt. Laser-Doppler Messungen der Grenzschichtprofile bestätigten das physikalische Konzept, durch die elektromagnetische Volumenkraft der Grenzschicht ein stabileres Profil aufzuprägen, welches bei höherem Elektrodenstrom in das eines Wandstrahles übergeht. Die Untersuchungen am Ruder waren vor allem auf die Unterdrückung der Strömungsablösung an der Saugseite des Profiles und die damit verbundene Auftriebserhöhung gerichtet. Dadurch konnte eine deutlich verbesserte Ruderwirkung erreicht werden. Experimentelle Weiterführungen des Konzeptes und Probleme infolge der auftretenden Elektrolyseblasen sowie Aspekte der Auswahl geeigneten Elektroden-materials werden diskutiert.

  • Poster
    Statusseminar "Technische Anwendungen von Erkenntnissen der Nichtlinearen Dynamik", Frankfurt, 23./24.02.1999, Tagungsband S. 205-208
  • Contribution to proceedings
    Statusseminar "Technische Anwendungen von Erkenntnissen der Nichtlinearen Dynamik", Frankfurt, 23./24.02.1999, Tagungsband S. 205-208

Permalink: https://www.hzdr.de/publications/Publ-1514
Publ.-Id: 1514


Kontrolle der Nichtlinearen Dynamik von Strömungsgrenzschichten - Anwendung bei Schiffen

Gerbeth, G.

Das Ablösen von Wirbeln an umströmten Körpern bzw. das Verständnis der körpernahen Strömungsgrenzschicht sind ein altes Problem der Strömungsforschung von offensichtlich großer praktischer Bedeutung. Der hochgradig nichtlineare Charakter dieser Phänomene beschränkt heute und auf absehbare Zeit die Möglichkeit einer direkten numerischen Simulation auf relativ niedrige, für praktische Zwecke wenig relevante Reynolds-Zahlen.
Für den Fall, dass die strömende Flüssigkeit eine elektrische Leitfähigkeit wie die von Seewasser hat, wird im Verbundprojekt die Idee einer gezielten Grenzschichtkontrolle mittels geeigneter elektromagnetischer Felder untersucht. Durch wechselweise Anordnung von Permanentmagneten und Elektroden kann, entsprechende Stromzufuhr an den Elektroden voraussgesetzt, eine Volumenkraft erzeugt werden, die die Strömungsgrenzschicht vollständig kontrolliert. Experimentelle Ergebnisse von Umströmungsmessungen an einer ebenen Platte und einem Ruder, durchgeführt an der Hamburgischen Schiffbauversuchsanstalt, zeigen eindeutig die starke elektromagnetische Kontrollmöglichkeit, die sich u.a. in einem erheblich reduzierten Strömungswiderstand oder einer Unterdrückung der Wirbelablösung niederschlägt. Die ernergetische Bilanz wird analysiert. Das Anwendungspotential im Schiffbau dieser relativ universell einsetzbaren Möglichkeit zur Strömungskontrolle wird aufgezeigt. Weiterführende, bisher nicht realisierte Varianten wie die Optimierung der Stromzufuhr oder der geometrischen Anordnung von Magneten und Elektroden werden diskutiert.


  • Lecture (Conference)
    Statusseminar Nichtlineare Dynamik, Frankfurt, 23./24.02.1999

Permalink: https://www.hzdr.de/publications/Publ-1513
Publ.-Id: 1513


Linearized solution of quasi-steady Stefan problem in vertical gradient freeze configuration

Grants, I.; Gerbeth, G.

The present paper deals with a shape of a sharp phase boundary under conductivity controlled quasisteady solidification in a long cylinder with a given surface temperature and growth velocity. An approximate analytical closed form solution is obtained linearizing the Stefan problem in a neighbourhood of the practically desirable planar interface. The relative error of the solution is evaluated numerically and shown below 15% for reasonable interface depths (1/2 of the crystal radius) and desreasing linearly (or more rapidly) as interface deformation decreases.

  • Journal of Crystal Growth Elsevier 207 (1999) 138-147

Permalink: https://www.hzdr.de/publications/Publ-1512
Publ.-Id: 1512


Spin-up instability of electromagnetically levitated spherical bodies

Gerbeth, G.; Priede, J.

Stability of a solid sphere in both uniform and linear alternating magnetic fields is considered with respect to virtual rotations. When the frequency of the alternating magnetic field exceeds certain critical threshold despending on the configuration of the field, the sphere is found to spin up around a horizontal axis. The physical mechanism of this instability is the same as that of operation of a single-phase electromotor. Sufficiently small rotational disturbances can be completely suppressed by imposing an axial steady magnetic field of strength comparable to hat of the alternating field. Non-linear stability analysis shows that for sufficiently high frequencies spin-up can be caused by large disturbances even when all infinitesimal disturbances are stable.

  • IEEE Transactions on Magnetics, Vol. 36. No. 1, Januar 2000

Permalink: https://www.hzdr.de/publications/Publ-1511
Publ.-Id: 1511


Oscillatory instability of electromagnetically levitated solid bodies

Priede, J.; Gerbeth, G.

This paper presents a linear-stability analysis of small-amplitude oscillations of a solid body suspended in an alternating magnetic field. An original theory is developed for an arbitrary configuration of the magnetic field. Stability of a solid sphere in an axisymmetric linear magnetic field is calculated analytically. Oscillations of the sphere are found to develop as the frequency of the field exceeds certain critical threshold relative to the characteristic diffusion time of the magnetic field in the sphere. The critical frequency for the onset of oscillations in linear magnetic field coincides with the critical frequency for the spin-up instability in uniform magnetic field. The growth rate of oscillations attains a maximum at some frequency above the threshold and tends to zero at high frequencies.

  • Journal IEEE Transactions on Magnetics, USA, Vol. 36. No. 1, pp. 354-357, January 2000

Permalink: https://www.hzdr.de/publications/Publ-1510
Publ.-Id: 1510


Electromagnetic control of flow around bodies

Gerbeth, G.

The flow around bodies (cylinder, plate) can be controlled by applying
electromagnetic forces originating from electrodes and permanent magnets
suitably placed on the surface of the body. There is a large variety for
applying those forces with respect to the geometrical arrangement and the
electrical current feeding the electrodes. The goals of this approach are
flow stabilization, drag reduction or manoeuvrability of the body in an
electrically low-conducting fluid like seawater.

Experimental and numerical results of our research programme will be
presented. Experiments were performed using a copper sulfate electrolytic
solution, a sodium hydroxide loop and large saltwater channels available at
a shipbuilding research center in Hamburg. A strong flow control has been
confirmed. The energetic limitations of the approach will be discussed

  • Lecture (others)
    Einladungsvortrag am LEGI Grenoble (04.02.1999)

Permalink: https://www.hzdr.de/publications/Publ-1509
Publ.-Id: 1509


Synthesis and Autoradiographical Evaluation of a Novel High-Affinity Tc-99m Ligand for the 5-HT2A Receptor

Pietzsch, H.-J.; Scheunemann, M.; Kretzschmar, M.; Elz, S.; Pertz, H. H.; Seifert, S.; Brust, P.; Spies, H.; Syhre, R.; Johannsen, B.

The synthesis and in vitro autoradiography of a novel Tc-99m ligand with subnanomolar affinity to the 5-HT2A receptor is reported. The complex combines the 4-(4-fluoro)-benzoyl piperidine portion derived from the 5-HT2A receptor antagonist ketanserin with a neutral oxotechnetium(V) chelate in form of a mixed ligand "3+1" unit containing the SNS/S donor set. The analogous rhenium compound has been synthesized as a surrogate for the Tc-99m complex for use in receptor binding assays and for complete structural characterization.
In competition experiments the Tc-99 complex as well as its Re analogue display subnanomolar affinity towards the 5-HT2A receptor (Ki 0.44 nM for Tc, 0.25 nM for Re).
The subnanomolar 5-HT2A receptor binding of the Re complex was confirmed by functional in vitro antagonism of contractile effects evoked by 5-HT in rat arterial tissue. Re 1 inhibited 5-HT-induced, 5-HT2A receptor-mediated contractions of isolated rat tail artery in a competitive fashion and possessed nanomolar affinity (pA2 = 9.08). Like ketanserin, Re 1 displayed moderate affinity for adrenergic alpha1D (pA2 = 8.23) and histamine H1 receptors (pA2 = 8.00), and was >600fold up to 10,700fold less active at several neurotransmitter receptor subtypes.
Autoradiographic studies clearly indicate the accumulation of the Tc-99m compound in 5-HT2A receptor rich areas of the brain. This enrichment can be blocked by 5-HT2A receptor antagonists such as mianserin and ketanserin and is therefore specific.

Keywords: Serotonin-5-HT2A receptor; Tc-99m receptor ligand; ketanserin analogue; ligand synthesis; in vitro autoradiography; receptor binding assay

  • Nuclear Medicine and Biology, 26 (1999) 865-875

Permalink: https://www.hzdr.de/publications/Publ-1508
Publ.-Id: 1508


A new mechano-optical technique to measure local velocities in opaque fluids

Eckert, S.; Witke, W.; Gerbeth, G.

A novel technique has been developed to measure the local velocities in opaque liquid flows such as liquid metals. The measuring principle is based on the separation of a direct mechanical interaction between flow and sensor tip and the optical acquisition and processing of the signal. In principle, this fact allows the extension of the range of applicability to higher temperatures. Furthermore, the insensitivity of the system to electrical noise and external magnetic fields can be considered as an
important advantage. Until now, the sensor has been tested in metallic melts up to temperatures of about 350 °C. We present measurements of the local velocity obtained in an eutectic InGaSn melt driven by a rotating magnetic field.

Keywords: flow measurement technique; local sensor; velocity; opaque fluids; liquid metals; mechano-optical principle; rotating magnetic field

  • Flow Measurement and Instrumentation, Vol. 11/2 (2000) 71-78

Permalink: https://www.hzdr.de/publications/Publ-1507
Publ.-Id: 1507


HEXNEM - A Nodal Method for the Solution of the Neutron Diffusion Equation in Hexagonal Geometry

Grundmann, U.

The nodal expansion method HEXNEM presented here bases on the transverse integration in axial direction and over the hexagonal plane of the nodes. For that, the 3-dimensional problem is split into a 2-dimensional problem in the hexagonal plane and a 1-dimensional problem in the z-direction. The 2-dimensional hexagonal problem is solved by an expansion of the neutron flux using two-dimensional polynomials and exponential functions being the solutions of the homogeneous equation. The transversal leakage term and the fission and scattering sources are approximated by the polynomials. To improve the accuracy, the method is not only based on the side averaged fluxes and currents but also on the corner point values. An analogous flux expansion is used for the solution of the 1-dimensional equation in axial direction. An inner and outer iteration procedure is applied to the solution of the problem. This method leads to an improvement of the accuracy against the simpler method implemented in the code DYN3D. It is shown by comparing the results with reference solutions of 2- and 3-dimensional benchmark problems.

Keywords: neutron diffusion; diffusion equation; nodal methods; 3-dimensional; benchmarks

  • Lecture (Conference)
    M & C '99 - Madrid Proc. of the International Conference on Mathematics and Computation, Reactor Physics and Enviromental Analysis in Nuclear Applications, pp. 1086-1094, Madrid, 27 - 30 September,1999
  • Contribution to proceedings
    M & C '99 - Madrid Proc. of the International Conference on Mathematics and Computation, Reactor Physics and Enviromental Analysis in Nuclear Applications, pp. 1086-1094, Madrid, 27 - 30 September,1999

Permalink: https://www.hzdr.de/publications/Publ-1506
Publ.-Id: 1506


Elastic plastic finite element analysis of a BWR feed water distributor exposed to an extreme pressure load

Altstadt, E.; Ohlmeyer, H.; Otremba, F.; Weiß, F.-P.

During a hypothetical break of a BWR feed water line, the feed water distributor (FWD) inside the RPV is subjected to a high pressure load for a short time (10 ms). Because of the sudden coolant release from the inner volume of the FWD there is a pressure difference between the inner and outer surface. It is conservatively assumed that the pressure difference nearly can reach the operating pressure for a few milliseconds. The distributor box and the ring line of the feed water distributor are modelled with shell and volume elements capable of being used for large strain analyses with elastic-plastic material behaviour. It is demonstrated by non-linear static calculations (without consideration of the inertia of the material) that a buckling instability occurs at about 60% and 80% of the maximum pressure load. The arc-length method is used for the numerical solution to overcome these points of instability. To evaluate the influence of the dynamics of the process a non-linear transient analysis is done showing that the maximum strain occurs with a time delay to the pressure peak. The maximum plastic strain differs only insignificantly between static and transient solution. Inspite of the large strains the mechanical integrity is maintained during the hypothetical event.

Keywords: BWR; Finite element analysis; Large strain; Plasticity; Transient analysis

  • Lecture (Conference)
    15-th International Conference on Structural Mechanics in Nuclear Technology (SMIRT-15), Seoul, Korea, August 15-20 1999, Proceedings Vol. VII pp. 177-184
  • Contribution to proceedings
    15-th International Conference on Structural Mechanics in Nuclear Technology (SMIRT-15), Seoul, Korea, August 15-20 1999, Proceedings Vol. VII pp. 177-184

Permalink: https://www.hzdr.de/publications/Publ-1505
Publ.-Id: 1505


Some Issues by Using the Master Curve Concept

Viehrig, H.-W.; Böhmert, J.

The master curve concept allows to determine limit curves of fracture toughness for defined failure probabilities and a reference temperatures based on it. Thus fracture mechanical values can be supplied for the stress analysis. This paper presents the application of the master curve concept for the determination of the reference temperature over the thickness of a plate of RPV steel. It was shown that the master curve concept is applicable for the fracture mechanical characterisation of material in different conditions using small test specimens. A special problem with the use small specimens is the definition of the test temperature, at which fracture toughness values can be determined within the validity limits. It became clear that the criteria for definition the test temperature and the minimum number of specimens indicated in the ASTM E1921-97 standard are applicable and sufficient respectively only for homogeneous materials.

Keywords: reactor pressure vessel steel; fracture mechanical assesment; trend curves; J-integral concept; fracture mechanical values

  • Lecture (Conference)
    Proc. of the 15th International Conference on Structural Mechanics in Reactor Technology (SmiRT-15), Seoul, Korea, August 1999, Vol. 5, p. 383-390
  • Contribution to proceedings
    Proc. of the 15th International Conference on Structural Mechanics in Reactor Technology (SmiRT-15), Seoul, Korea, August 1999, Vol. 5, p. 383-390

Permalink: https://www.hzdr.de/publications/Publ-1504
Publ.-Id: 1504


On the uniqueness of velocity reconstruction in conducting fluids from measurements of induced electromagnetic fields

Stefani, F.; Gerbeth, G.

The problem of velocity reconstruction in conducting fluids from measurements of induced magnetic fields and electric potentials is discussed in spherical geometry.
Under the special case that the externally applied magnetic field is uniform and homogeneous throughout the fluid, the non-uniqueness problem is treated in detail. Assuming kinetic energy minimization for the moving fluid it is shown that the velocity field can be reconstructed completely.

Keywords: Inverse Problems; Magnetohydrodynamics

  • Inverse Problems 16 (2000), pp. 1-9

Permalink: https://www.hzdr.de/publications/Publ-1503
Publ.-Id: 1503


Methodische Untersuchungen zum Einsatz von Positronenemittern für die Dichtebestimmung in leichten Medien

Hensel, F.

In der vorliegenden Arbeit wird der Einsatz von Positronenemittern zur Bestimmung der Dichte eines zweiphasigen Mediums beschrieben. Zur Messung wird die Dichteabhängigkeit der Positronenreichweite ausgenutzt. Die Realisierbarkeit des Verfahrens wird zunächst in einer Computersimulation geprüft. Danach werden Experimente an einem hochauflösenden PET-Scanner vorgestellt. Bei diesen Experimenten wird die Dichteabhängigkeit der Reichweite von Positronen anhand von Modellmedien aus festen Schaumstoffen untersucht. Dabei werden die in der Computersimulation erzielten Ergebnisse bestätigt. Aus den experimentellen Ergebnissen wird ein Modell zur Beschreibung der Abnahme der Koinzidenzrate in Abhängigkeit von der Entfernung des Detektors von der Positronenquelle und der Mediendichte entwikkelt. Auf der Basis des Modells erfolgt die Konzipierung einer für die Dichtemessung optimierten Detektoranordnung. Die Funktionsweise dieses Detektorsystems wird in Form technischer Unterlagen und experimenteller Ergebnisse beschrieben. Mit dem optimierten Detektorsystem werden die Untersuchungen an den Modellmedien nochmals durchgeführt, wobei die bisherigen Ergebnisse bestätigt werden.

Das beschriebene Meßverfahren dient der Bestimmung der mittleren Dichte in einem überwiegend gasförmigen Medium, wobei eine Mittelwertbildung über das Meßvolumen erfolgt. Das Verfahren kombiniert die Vorteile bekannter densitometrischer Meßmethoden auf der Basis einer Schwächung von Strahlung, indem die hohe Dichtesensitivität der Positronenstrahlung mit der relativ geringen Absorption der energiereichen Annihilationsquanten kombiniert wird.

Keywords: densitometry; positron; positron range; positron emitters; foam; two-phase flow; polymer foam; annihilation radiation detection; coincidence detection; CAMAC applications

  • Open Access Logo Wissenschaftlich-Technische Berichte / Forschungszentrum Rossendorf; FZR-254 Februar 1999, ISSN 1437-322X
    ISSN: 1437-322X

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Permalink: https://www.hzdr.de/publications/Publ-1500
Publ.-Id: 1500


Complex formation of Uranium(IV) with Phosphate studied by laser-induced photoacoustic spetrosopy

Geipel, G.; Bernhard, G.; Brendler, V.; Rutsch, M.; Nitsche, H.

Uranium can occur in reducing phosphate-containing environments as uranium(IV)-hadrogenphosphate, U(HPO4)2.4H2O. No thermodynamic complex formation constants are available for the uranium(IV)-phosphate complexes because of their low water solubility. For example, the solubility product /1/ of U(HPO4)2.4H2O limits the uranium(IV) concentration in 1 M perchloric acid to less than 1.2 x 10-4 M. We studied the formation of this complex at uranium concentrations between 2x10-6 M and 1x10-4M by Laser-Induced Photoacoustic Spectroscopy in acid media. To determine the complex formation constant we measured and analyzed the spectra from 610 nm to 690 nm. The spectra were corrected for the absorption of the solvent water. The solvated uranium(IV) shows a very intensive absorption band with a maximum at 649.8 nm and a smaller maximum at 671.9 nm. We found a shoulder at 630.0 nm by deconvoluting the absorption spectrum. The spectrum changes with increasing phosphate concentration. At a total phosphate concentration of 1.5x10-3M, we found maxima at 656.6 nm and 667.0 nm. Additionally a shoulder at 645.0 nm is found. Two isosbestic points were determined at 661.4 nm and 669.4 nm. Results will be presented for the determination of the formation equilibrium and the complex formation constant(s).

  • Lecture (Conference)
    Migration´99, Village

Permalink: https://www.hzdr.de/publications/Publ-1499
Publ.-Id: 1499


Classification of Desulfovibrio isolates recovered from a uranium mining weaste pile

Wober, J.; Flemming, K.; Pietzsch, K.; Hard, B.; Selenska-Pobell, S.

A large variety of bacteria was demonstrated to be present in soil and sediment samples of a uranium waste pile in Saxony, Germany. Anaerobic sulfate-reducing bacteria belonging to the genus Desulfovibrio were found among them. The study of these bacteria, which are also known to reduce U(VI), is of great importance for the development of bioremediation procedures for decontamination of the environments polluted with uranium. The indigenous for the waste Desulfovibrio isolates were classified by the use of Amplified Ribosomal DNA Restriction Endonucleases Analysis (ARDREA), Random Amplified Polymorphic DNA (RAPD), Repetitive Primer Amplified Polymorphic DNA (rep-APD), 16S rDNA Sequencing, and as well as with classical microbiological methods.
Using 16S- and IGS-ARDREA the pile isolates were phylogenetically affiliated to Desulfovibrio vulgaris (oxamicus). The RAPD and rep-APD analyses have demonstrated a close genomic relationship between the pile isolates, but D. vulgaris (oxamicus) 1925T was not closely related to them. These results are in agreement to the taxonomic characterization of the strains by comparison of the fatty acid spectra.

  • Poster
    VAAM-Conference, Göttingen

Permalink: https://www.hzdr.de/publications/Publ-1498
Publ.-Id: 1498


Molecular charakterization of Thiobacillus isolates recovered from a uranium mining waste pile

Kutschke, S.; Selenska-Pobell, S.


In natural bioleaching systems autochtonic microorganisms are involved in the solubilization of metals from solid minerals. The widest spreaded mesophilic group of bioleaching microorganisms are the chemolithoautotrophic bacteria Thiobacillus ferrooxidans, Thiobacillus thiooxidans and Leptospirillum ferrooxidans.
From the soil samples of different sites and depths of a former uranium mine in Saxony, Germany, several Thiobacillus strains were cultured. They were classified by the use of the amplified ribosomal DNA restriction enzyme analysis (ARDREA). The genomic organization of the strains was investigated using random amplified polymorphic DNA (RAPD) and pulsed-field gel electrophoresis (PFGE).
All strains were affiliated to the species T. ferrooxidans. Moreover, it was possible to distinguish members belonging to the two closely related phylogenetic groups of the species - one related to the reference strain T. ferrooxidans ATCC 33020 (recovered from a uranium mine) and a second one, related to the strain 21834 (recovered from a coal mine).
By the use of the RAPD and PFGE fingerprinting methods it was demonstrated that the strains recovered from different depths differ in their genomic organization.

  • Poster
    VAAM-Conference, Göttingen

Permalink: https://www.hzdr.de/publications/Publ-1497
Publ.-Id: 1497


Bacterial Diversity and Activity in Uranium Waste Piles

Selenska-Pobell, S.; Flemming, K.; Kutschke, S.; Panak, P.; Satschanska, G.

Bacterial diversity in subsurface soil samples drawn from different depths of several uranium waste piles was studied using the 16S rDNA retrieval. Extremely high diversity was found in all samples investigated. In particular, the presence of several dominant 16S rDNA groups related to the genara $\I Thiobacillus, Bacillus, Pseudomonas, Desulfovibrio $$END was demonstrated. One of these 16S rDNA groups was affiliated to the species $\IT. ferrooxidans$$END. Interestingly, this group includes three 16S rDNA types which possess slightly different sequences. Strains of $\IT. ferrooxidans$$END corresponding to two of the mentioned three 16S rDNA types were recovered from two soil samples polluted in different extend with heavy metals. The two groups of isolates have different genomic organization. In addition, the members of the group recovered from the more polluted sample are tollerant to higher concentrations of uranyl ions which are lethal for the isolates of the second group. The expression of at least three genes of the U-tolerant strains is influenced by by the presence of uranyl ions in the nutrient medium. The capability of the U-mine isolates to interact with U(VI) was studied, and it was found that they accumulate significantly higher amounts of U(VI) in comparison to several reference $\IT. ferrooxidans$$END strains recovered from other environments. Using time-resolved laser fluorescence spectroscopy it was shown that the complexes build by one of the U-waste isolates with U(VI) are much stronger than those build by the reference strains. This is the first report which demonstrates a microdiversity in closely related natural isolates of $\IT. ferrooxidans$$END. We suggest that the microdiversity obsrved reflects the genetic adaptation of the strains studied to the different heavy metal concentrations in their natural environments.

  • Lecture (Conference)
    ISSM 4th Conference, Colorado

Permalink: https://www.hzdr.de/publications/Publ-1496
Publ.-Id: 1496


Classification of Desulfovibrio isolates recovered from a uranium mining waste pile

Wober, J.; Flemming, K.; Selenska-Pobell, S.


A large variety of bacteria was demonstrated to be present in soil and sediment samples of a uranium waste pile in Saxony, Germany. Anaerobic sulfate-reducing bacteria belonging to the genus Desulfovibrio were found among them. The study of these bacteria, which are also known to reduce U(VI), is of great importance for the development of bioremediation procedures for decontamination of the environments polluted with uranium. The indigenous for the waste Desulfovibrio isolates were classified by the use of Amplified Ribosomal DNA Restriction Endonucleases Analysis (ARDREA), Random Amplified Polymorphic DNA (RAPD), Repetitive Primer Amplified Polymorphic DNA (rep-APD), and 16S rDNA Sequence.
The 16S and IGS rDNA retrieval allowed us to affiliate the natural Desulfovibrio isolates to the subspecies Desulfovibrio vulgaris (oxamicus). Using RAPD and rep-APD analyses, the natural isolates were grouped in particular cluster which was not very closely related to the type strain D. vulgaris (oxamicus) 1925T. Results demonstrating the capability of the uranium waste isolates to reduce U(VI) to U(IV) will be presented.

  • Lecture (Conference)
    BAGECO 6th Symposium, Florenz

Permalink: https://www.hzdr.de/publications/Publ-1495
Publ.-Id: 1495


Bacterial diversity and activity in Uranium waste piles

Selenska-Pobell, S.; Flemming, K.; Kutschke, S.; Panak, P.; Satschanska, G.; Wober, J.


Bacterial diversity in soil samples drawn from different depths of several uranium waste piles was studied using 16S rDNA retrieval, RISA and rep-APD. Extremely high diversity was found in all samples investigated. Several dominant 16S rDNA groups related to the genera Thiobacillus, Bacillus, Pseudomonas, and Desulfovibrio were demonstrated. One of these groups was affiliated to the species T. ferrooxidans. This group includes three 16S rDNA types with slightly different sequences. Strains of T. ferrooxidans corresponding to two of the mentioned three 16S rDNA types were recovered from two samples of the waste polluted in different extend with heavy metals. The interactions of the natural T. ferrooxidans strains with U(VI) were group-specific. Microdiversity at the level of 16S- and IGS-rDNA was found also among the group of the uranium reducing Desulfovibrio waste isolates. The latter were affiliated to Desulfovibrio vulgaris subspecies oxamicus. These natural isolates are able to reduce more effectively higher amounts of U(VI) than the reference Desulfovibrio strains. In contrast to the reference strains, the waste isolates reduce U(VI) to U(IV) independently of the pH range of the medium. This is the first report demonstrating microdiversity of closely related natural isolates of T. ferrooxidans and D. vulgaris subsp. oxamicus. We suggest that the microdiversity observed reflects the genetic adaptation of the strains studied to the different heavy metal concentrations in their natural environments.

  • Lecture (Conference)
    BAGECO 6th Symposium, Florenz

Permalink: https://www.hzdr.de/publications/Publ-1494
Publ.-Id: 1494


Charakterization of Thiobacillus isolates from a Uranium mining waste pile

Kutschke, S.; Panak, P.; Selenska-Pobell, S.

In the natural bioleaching systems autochtonic microorganisms are involved in the solubilization of metals from solid minerals. The widest spreaded mesophilic group of bioleaching microorganisms are the chemolithoautotrophic bacteria Thiobacillus ferrooxidans, Thiobacillus thiooxidans, and Leptospirillum ferrooxidans.
From soil samples drawn from two particular sites of a former uranium mine in Saxony, Germany, which were polluted in different extend with heavy metals, several Thiobacillus strains were cultured. Using ARDREA the strains were classified in two uranium-waste-site-specific 16S rDNA subgroups of the species Thiobacillus ferrooxidans. Moreover, RAPD and PFGE analyses have demonstrated that the natural T. ferrooxidans isolates possess also group-specific genomic organization. The strains from the more polluted sample were tolerant to higher concentrations of uranyl ions which were lethal for the isolates of the second group. In these strains the expression of at least three genes was influenced by the presence of uranyl ions. The uranium binding capability of the uranium mine isolates was strain-specific and higher than those of the reference T. ferrooxidans strains recovered from other environments.

  • Lecture (Conference)
    BAGECO 6th Symposium, Florenz

Permalink: https://www.hzdr.de/publications/Publ-1493
Publ.-Id: 1493


Spectroscopic properties of Uranium(VI) minerals studied by time-resolved laser-induced fluorescence spectroscopy (TRLFS)

Geipel, G.; Bernhard, G.; Brendler, V.; Rutsch, M.; Nitsche, H.

About 160 uranium minerals are known. Although many of these minerals show fluorescence properties, detailed fluorescence spectra are not published in the literature. We studied the fluorescence properties of 120 uranium minerals in order to provide a data base of potential solids that may form in the flooding process of defunct uranium mines.

  • Poster
    Migration´99, Conference Incline Village, CA

Permalink: https://www.hzdr.de/publications/Publ-1491
Publ.-Id: 1491


Investigation of Humic Acid Complexation Behavior with UO2 2+ Ions using Modified Synthetic and Natural Humic Acids

Pompe, S.; Schmeide, K.; Bubner, M.; Geipel, G.; Heise, K.-H.; Bernhard, G.; Nitsche, H.

Humic acids influence the speciation and migration behavior of actinide ions in the environment. Due to their complex and heterogeneous nature, a thermodynamically based description of their complexation behavior with metal ions is difficult. Numerous uncertainties exist in the description of the complexation process, e.g., the kind and number of complexing functional groups is uncertain.
We are investigating the influence of different functional groups on the complexation behavior of humic acids to improve the understanding of the humic acid - metal ion interaction. Such information is very important for a more precise modeling of geochemical processes in the presence of humic acids.
We synthesized and characterized synthetic and natural humic acids with blocked phenolic hydroxyl groups. With these humic acids, we investigate the influence of phenolic hydroxyl groups on the complexation behavior of humic acids with UO22+ ions. The investigations were carried out by laser-induced fluorescence spectroscopy and FTIR spectroscopy.
For the first time, we compared the complexation behavior of a modified and non-modified synthetic humic acid with UO22+ ions at pH 4 by laser-induced fluorescence spectroscopy. The spectroscopic results show that the blocking of the phenolic hydroxyl groups changes the interaction behavior between the humic acid and the UO2 2+ ion.

  • Lecture (Conference)
    Migration´99 - Conference, Incline Village, Lake Tahoe, USA, 26.9.-1.10.1999

Permalink: https://www.hzdr.de/publications/Publ-1489
Publ.-Id: 1489


Effect of Humic Acid on the Uranium(VI) Sorption onto Phyllite and its Mineralogical Constituents

Schmeide, K.; Pompe, S.; Bubner, M.; Heise, K.-H.; Bernhard, G.; Nitsche, H.


Organic materials, such as humic and fulvic acids, that are present in natural aquifers interact with dissolved inorganic contaminants and affect their sorption behavior on geological materials and thus, their migration in aquifers. Consequently, a quantification of the influence of humic material on radionuclide sorption is necessary.
Phyllite was used as site-specific rock material because it is quite common in the Western ‘Erzgebirge' in Saxony, Germany, and is closely associated with uranium deposits of the uranium mining areas in East Germany. Site specific humic acid, isolated from the bog ‘Kleiner Kranichsee' and a 14C-labelled synthetic humic acid were used for the experiments.
The effect of humic acid was studied on the sorption behavior of uranium(VI) onto phyllite and its mineralogical components muscovite, albite and quartz in air-equilibrated batch experiments as a function of pH. The uranium sorption is strongly affected by both the pH and the presence of organic material. The kinetics and reversibility of the uranium and humic acid sorption were studied using the 14C-labelled humic acid. Furthermore, the influence of competing sulfate ions on the uranyl and humic acid sorption onto phyllite was determined, because seepage waters of the uranium mining areas in Saxony contain, among other anions, relatively high concentrations of sulfate (3 10-2 M).


  • Poster
    Migration´99 - Conference

Permalink: https://www.hzdr.de/publications/Publ-1488
Publ.-Id: 1488


Azimuthal anisotropies as stringent test for nuclear transport models

Crochet, P.; Rami, F.; Dona, R.; Coffin, J. P.; Fintz, P.; Guillaume, G.; Jundt, F.; Kuhn, C.; Roy, C.; de Schauenburg, B.; Tizniti, L.; Wagner, P.; Alard, J. P.; Andronic, A.; Basrak, Z.; Bastid, N.; Belyaev, I.; Bendarag, A.; Berek, G.; Best, D.; Biegansky, J.; Buta, A.; Caplar, R.; Cindro, N.; Dupieux, P.; Dzelalija, M.; Fan, Z. G.; Fodor, Z.; Fraysse, L.; Freifelder, R. P.; Gobbi, A.; Herrmann, N.; Hildenbrand, K. D.; Hong, B.; Jeong, S. C.; Kecskemeti, J.; Kirejczyk, M.; Koncz, P.; Korolija, M.; Kotte, R.; Lebedev, A.; Leifels, Y.; Manko, V.; Moisa, D.; Mösner, J.; Neubert, W.; Pelte, D.; Petrovici, M.; Pinkenburg, C.; Reisdorf, W.; Ritman, J. L.; Sadchikov, A. G.; Schüll, D.; Seres, Z.; Sikora, B.; Simion, V.; Siwek-Wilczynska, K.; Sodan, U.; Teh, K. M.; Trzaska, M.; Wang, G. S.; Wessels, J. P.; Wienold, T.; Wisniewski, K.; Wohlfarth, D.; Zhilin, A.

  • Nuclear Physics A 627 (1997) 522-542

Permalink: https://www.hzdr.de/publications/Publ-1486
Publ.-Id: 1486


Charged pions from Ni on Ni collisions between 1 and 2 AGeV

Pelte, D.; Eskef, M.; Goebels, G.; Häfele, E.; Herrmann, N.; Korolija, M.; Merlitz, H.; Mohren, S.; Trzaska, M.; Alard, J. P.; Amouroux, V.; Andronic, A.; Basrak, Z.; Bastid, N.; Belyaev, I.; Best, D.; Biegansky, J.; Buta, A.; Caplar, R.; Cindro, N.; Coffin, J. P.; Crochet, P.; Dupieux, P.; Dzelalija, M.; Erö, J.; Fintz, P.; Fodor, Z.; Genoux-Lubain, A.; Gobbi, A.; Guillaume, G.; Hildenbrand, K. D.; Hong, B.; Jundt, F.; Kecskemeti, J.; Kirejczyk, M.; Koncz, P.; Korchagin, Y.; Kotte, R.; Kuhn, C.; Lambrecht, D.; Lebedev, A.; Legrand, I.; Leifels, Y.; Manko, V.; Mösner, J.; Moisa, D.; Neubert, W.; Petrovici, M.; Pinkenburg, C.; Pras, P.; Rami, F.; Ramillien, V.; Reisdorf, W.; Vasiliev, M. A.; Wagner, P.; Wang, G. S.; Wienold, T.; Wohlfarth, D.; Zhilin, A.

  • Zeitschrift für Physik A 359, 55-64 (1997)

Permalink: https://www.hzdr.de/publications/Publ-1485
Publ.-Id: 1485


Verhinderung des Kavitationsschlages beim schnellen Absperren einer Flüssigkeitsleitung

Dudlik, A.; Prasser, H.-M.; Schlüter, S.

Beim Schließen einer schnellwirkenden Absperrarmatur in einer Rohrleitung, in der eine Flüssigkeit strömt, kann es zu Kavitationsschlägen kommen. In vielen technischen Anwendungen ist ein möglichst rasches Absperren von Rohrleitungen erforderlich, insbesondere wenn es um die Beherrschung von Störungen geht. Es wird eine Methode zur Verhinderung des Kondensationsschlages vorgeschlagen. Sie besteht in der Einführung einer Hilfsarmatur, die sich hinter der eigentlichen Absperrarmatur befindet. Diese Hilfsarmatur wird zu dem Zeitpunkt geschlossen, an dem die Kavitationsblase ihre größte Ausdehnung in der Rohrleitung erreicht hat. Die Blase wird dadurch zwischen den beiden Armaturen eingeschlossen und so am Kollabieren gehindert. Im Vortrag werden die Meßergebnisse vorgestellt, die Rohrleitungs-Versuchsfeld von Fraunhofer UMSICHT mit Zweiphasen-Meßtechnik aus Rossendorf erhalten wurden. Die Auslegungskriterien für eine solche Anordnung werden diskutiert.

  • Lecture (Conference)
    4. VDI-Fachtagung Anlagen-, Arbeits- und Umweltsicherheit, Köthen, 5.-6. November 1998
  • Contribution to proceedings
    4. VDI-Fachtagung Anlagen-, Arbeits- und Umweltsicherheit, Köthen, 5.-6. November 1998, Preprints, Vortrag V18, 5./6.

Permalink: https://www.hzdr.de/publications/Publ-1482
Publ.-Id: 1482


Physical Information in the Thermal Continuum Dilepton Spectra

Gallmeister, K.; Kämpfer, B.; Pavlenko, O. P.

  • Contribution to external collection
    Progress in Particle and Nuclear Physics 42 (1999) 333-334

Permalink: https://www.hzdr.de/publications/Publ-1481
Publ.-Id: 1481


Dileptons, Charm and Bottom in Relativistic Heavy-Ion Collisions

Kämpfer, B.; Pavlenko, O. P.; Gallmeister, K.

  • Contribution to external collection
    Progress in Particle and Nuclear Physics 42 (1999) 335-343

Permalink: https://www.hzdr.de/publications/Publ-1480
Publ.-Id: 1480


Synthesis and preliminary binding affinities of 1(1,2-dihydro-2-acenaphthylenyl)piperazine - a new arylpiperazine

Srinivas, P.; Brust, P.; Subramanian, A. R.; Raghavan, S. A. V.; Rangisetty, J. B.; Gupta, C. N. V. H. B.; Parimoo, P.

The first synthesis of 1-(1,2-dihydro-2-acenaphthylenyl)piperazine (5) – a new arylpiperazine is described. Preliminary binding studies on this new arylpiperazine reveal affinity for the 5-HT1A and 5-HT2A receptor subtypes. Incorporation of a dopamine pharmacophore onto this arylpiperazine provided compound (7) a potential antipsychotic with an atypical profile.

Keywords: Arylpiperazine; 1-(1,2-dihydro-2-acenaphthylenyl)piperazine; 5-HT; Dopamine; Atypical antipsychotic

  • Pharmaceutica Acta Helvetiae 74 (1999) 73-73

Permalink: https://www.hzdr.de/publications/Publ-1479
Publ.-Id: 1479


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