By simulation experiments with a 10–5 mol/l solution of iodododecane labeled with131I in n-dodecane the influence of various materials and conditions, which are possible in nuclear fuel reprocessing, has been investigated. The formation of decomposition products was detected via HPLC with a radioactivity monitor. By means of252Cf plasma-desorption mass spectrometry (PDMS) the decomposition products were identified. It was found that a temperature of 100°C favored the formation of iodoalkanes with chain lengths of C1 to C11. The presence of TBP(tri-n-butyl-phosphate) accelerated the decomposition of iodododecane. In pure TBP only iodobutane was formed as a decomposition product.
Authors:O. Kindel, F. Herrmann, L. Schmidt, and P. Patzelt
In kerosene samples from nuclear fuel reprocessing, iodoalkanes with chain-lengths from C4 to C13 have been identified. The kerosene samples were purified by means of solid-phase extraction. By this method other fission products like125Sb and106Ru were quantitatively removed from the solution. The only remaining radioactive nuclide was thus129I. The iodoorganic compounds in the kerosene from the solvent were enriched from 6000 Bq/L to 100 000 Bq/L129I by vacuum distillation. Chromatographic separation by HPLC, fractionation, and -measurement of the fractions showed that at least one polar and one nonpolar iodoorganic compound were present. Derivatisation of the iodoorganic compounds with, 1,4-diazabicyclo-2,2,2-octane to quatermary ammonium salts and252Cf plasma desorption mass spectrometry of the products revealed that the main iodoorganic constituents in the kerosene were iodobutane as polar and iodododecane as nonpolar compound in approximately equal concentrations.
Authors:O. Kindel, V. Hoeflich, F. Herrmann, and P. Patzelt
A 10–5 mol 1–1 solutiopn of idododecane in n-dodecane was used to simulate a kerosene sample from nuclear fuel reporcessing. Several methods were developed for the quantitative removal of iodododecane from the n-dodecane solution. Decomposition to elemental iodine was achieved either by washing with hyperazeotropic nitric acid or by exposure to a high-intensity UV-light. Quantitative removal of iodododecane from n-dodecane was achieved by absorption on silver nitrate impregnated materila or on activated charcoal, which was impregnated with potassium thiocyanate or 1,4-diazabicyclo-2,2,2-octance. The reaction could be accelerated by stirring or heating. Thus a quantitative absorption of idododecane could be achieved within a few minutes. The results of the experiments were confirmed by absorption of iodoorganic compounds from kerosene of the Karl sruhe nuclear fuel reprocessing plant (WAK) on the tested material.
Authors:R. Bugoi, V. Cojocaru, B. Constantinescu, F. Constantin, D. Grambole, and F. Herrmann
Several fragments of ancient gold objects coming from an Eneolithic hoard and from Pietroasa Cloca cu Puii de Aur (The Golden Brood Hen with Its Chickens) hoard, unearthed on Romanian territory, and two Romanian native gold nuggets samples were analyzed using micro-PIXE technique. The purpose of the study was to clarify the metal provenance. Trace and minor elements (Cu, Te, Sn, Pb, Ti, Cr, V, Mn, Ta) and platinum group elements (PGE) concentrations were estimated. The presence of inclusions (micrometer size areas of composition different from the surroundings) was investigated. We found Si and Ca inclusions on two Eneolithic samples, and Ta inclusions on two samples from Pietroasa hoard. The measurements suggested an alluvial origin of gold for the Eneolithic samples and give indications for the possible gold ore sources of Pietroasa hoard.
Authors:J. Herrmann, U. Kormann, C. Schüepp, Y. Stocker, F. Herzog, and M. Entling
Habitat isolation is expected to reduce population densities of animals via reduced immigration. However, altered trophic interactions in isolated habitats may modify these effects, especially since the strength of isolation effects is expected to increase with trophic rank. Here, we studied effects of habitat isolation on a food-web module consisting of herbivorous beetles, predatory spiders, spider-preying wasps and arthropod-feeding birds. We compare two systems that were studied in subsequent years: a study on 29 mature apple orchards that varied in the degree of isolation from forest, and a study on 20 groups of newly planted cherry trees that showed similar variation in their degree of habitat isolation. No birds were observed on the young fruit trees. Wasps and spiders showed the expected lower abundances in isolated habitats. On mature trees, birds were present and showed lower abundances in isolated habitats. Wasps were reduced to a similar degree by habitat isolation as on the young trees. Surprisingly, spider densities on the mature trees were higher in isolated than in connected habitat. This contrasting response of spiders to habitat isolation is likely to be due to release from bird predation in isolated mature orchards. In both study systems, beetles showed no significant effect of habitat isolation. Our results confirm that the sensitivity to fragmentation increases with trophic rank, and suggest that trophic interactions should receive more attention in fragmentation studies.
Authors:W. Rudolph, C. Bauer, P. Gippner, D. Grambole, C. Heiser, F. Herrmann, and H. Thomas
Hydrogen surface contamination and depth profiles can be measured by the resonant nuclear reactions1H(19F,
)12C. The method was applied to study hydrogen-implanted silicon, amorphous silicon layers and silicon oxide films produced by anodic oxidation.
Authors:J. Alstad, G. Skarnemark, F. Haberberger, G. Herrmann, A. Nähler, M. Pense-Maskow, and N. Trautmann
The H-0.3 liquid-liquid centrifuge applied for rapid and efficient separation of two liquid phases, and the HG-0.1 gas-liquid centrifuge used to separate the gas phase stemming from a gas jet transportation system and the liquid phase, have been further improved. New centrifuges have been produced of PEEK, a plastic material, which makes them resistant to most aqueous and organic solutions. The performance with respect to time behavior and phase purity is comparable to the titanium centrifuges used so far. The H-0.3 centrifuge has been applied to solvent extraction studies of Zr, Nb, Mo, Hf, Ta, W and Pa from HF solutions into tri-n-octylamine.
Authors:K. Aleklett, R. Brandt, M. Bronikowski, V. Butsev, B. Chasteler, G. Dersch, G. Feige, E. Friedlander, E. Ganssauge, G. Haase, J. Herrmann, D. Hoffman, B. Judek, P. Kosma, B. Kulakov, E. Langrock, D. Lee, W. Loveland, F. Pille, N. Porile, W. Schulz, and G. Seaborg
In recent years the question of the unusual behavior of projectile fragments formed in the interaction of relativistic heavy ions with copper nuclei was studied using nuclear chemistry techniques. As targets we used various copper disk arrangements. It is not the intention of this conference contribution to give a complete account of the entire procedure and its results. However, we want to present a few more recent experimental findings, some of them even in a preliminary form. We want to stimulate the discussion about the entire problem which might be part of the so-called anomalon phenomenon, as observed in the field of relativistic heavy ion interactions with a few other techniques such as nuclear emulsions or bubble chambers.