Miocene to Pleistocene gluconite-rich layers of the US Mid-Atlantic margin

Glauconite is generally agreed to be a reliable indicator of low sedimentation rate, but little systematic work has been done to specify the role of glauconite in a sequence-stratigraphic framework. Ocean Drilling Program Leg 174A recovered a good record of late Tertiary sediments along the shelf edge of the New Jersey US Atlantic margin, and glauconite was present in many intervals of the cores, sometimes in vertical proximity to sequence boundaries. Leg 174A glauconite was analyzed with binocular microscope, XRD and SEM to determine the percent of potassium and degree of maturity in order to relate occurrence to depositional environment. Seismic data were used to locate sequence boundaries, and percent glauconite was visually estimated. Glauconite samples from Site 1073 were found to have formed within a lowstand systems tract (LST), and as part of a distal condensed section (CS) within a transgressive systems tract (TST). These results are comparable to those from nearby Site 903 of Leg 150, which indicate a similar depositional setting for glauconite. Glauconites at shelf Sites 1071 and 1072 likely formed in the TST as well. Onshore, glauconite occurs mainly in transgressive systems tracts. The Miocene appears to be the upper limit of glauconite formation onshore. As the magnitude of sea-level change decreased, present onshore locations became too nearshore to maintain sediment-free environments, and the zone of glauconite deposition moved seaward. The same process did not occur offshore until the Plio-Pleistocene. Low subsidence-rate margins such as the US Atlantic are subject more to the variations of sea-level than to changes in sediment supply, tectonics, or other factors influencing their depositional patterns. Although glauconite occurrence is widespread in the stratigraphic record, this study demonstrates that for low subsidence-rate margins, primary deposition of glauconite is largely restricted to the TST.

Roślinność wodna, błotna i bagienna północnej części Dolnych Łużyc

Wydział Biologii

Measurement of picosecond lifetimes in neutron-rich Xe isotopes

Background: Lifetimes of nuclear excited states in fission fragments have been studied in the past following isotope separation, thus giving access mainly to the fragments' daughters and only to long-lived isomeric states in the primary fragments. For the first time now, short-lived excited states in the primary fragments, produced in neutron-induced prompt fission of U-235 and Pu-241, were studied within the EXILL&FATIMA campaign at the intense neutron-beam facility of the Institute Laue-Langevin in Grenoble. Purpose: We aim to investigate the quadrupole collective properties of neutron-rich even-even Xe-138,Xe-140,Xe-142 isotopes lying between the double shell closure N = 82 and Z = 50 and a deformed region with octupole collectivity. Method: The gamma rays emitted from the excited fragments were detected with a mixed array consisting of 8 HPGe EXOGAM Clover detectors (EXILL) and 16 LaBr3(Ce) fast scintillators (FATIMA). The detector system has the unique ability to select the interesting fragment making use of the high resolution of the HPGe detectors and determine subnanosecond lifetimes using the fast scintillators. For the analysis the generalized centroid difference method was used. Results: We show that quadrupole collectivity increases smoothly with increasing neutron number above the closed N = 82 neutron shell. Our measurements are complemented by state-of-the-art theory calculations based on shell-model descriptions. Conclusions: The observed smooth increase in quadrupole collectivity is similar to the evolution seen in the measured masses of the xenon isotopic chain and is well reproduced by theory. This behavior is in contrast to higher Z even-even nuclei where abrupt change in deformation occurs around N = 90.

Swedish-speaking Finns: a multi-method qualitative study of belonging and identification

The Swedish-speaking minority in Finland, often described as an ‘elite minority’, holds a special position in the country. With linguistic rights protected by the constitution of Finland, Swedish-speakers, as a minority of only 5.3%, are often described in public discourse and in academic and statistical studies as happier, healthier and more well off economically than the Finnish-speaking majority. As such, the minority is a unique example of language minorities in Europe. Knowledge derived from qualitatively grounded studies on the topic is however lacking, meaning that there is a gap in understanding of the nature and complexity of the minority. Drawing on ethnographic research conducted in four different locations in Finland over a period of 12 months, this thesis provides a theoretically grounded and empirically informed rich account of the identifications and sites of belonging of this diverse minority. The thesis makes a contribution to theoretical, methodological and empirical research on the Swedish-speaking minority, debates around identity and belonging, and ethnographic methodological approaches. Making use of novel methodology in studying Swedish-speaking Finns, this thesis moves beyond generalisations and simplifications on its nature and character. Drawing on rich ethnographic empirical material, the thesis interrogates various aspects of the lived experience of Swedish-speaking Finns by combining the concepts of belonging and identification. Some of the issues explored are the way in which belonging can be regionally specific, how Swedish-speakers create Swedish-spaces, how language use is situational and variable and acts as a marker of identity, and finally how identifications and sites of belonging among the minority are extremely varied and complex. The thesis concludes that there are various sites of belonging and identification available to Swedish-speakers, and these need to be studied and considered in order to gain an accurate picture of the lived experience of the minority. It also argues that while identifications are based on collective imagery, this imagery can vary among Swedish-speakers and identifications are multiple and situational. Finally, while language is a key commonality for the minority, the meanings attached to it are not only concerned with ‘Finland Swedishness’, but connected to various other factors, such as the context a person grew up in and the region one lives in. The complex issues affecting the lived experience of Swedish-speaking Finns cannot be understood without the contribution of findings from qualitative research. This thesis therefore points towards a new kind of understanding of Swedish-speaking Finns, moving away from stereotypes and simplifications, shifting our gaze towards a richer perception of the minority.

An approximate method for the solution of an influence function foil rolling model

Fleck and Johnson (Int. J. Mech. Sci. 29 (1987) 507) and Fleck et al. (Proc. Inst. Mech. Eng. 206 (1992) 119) have developed foil rolling models which allow for large deformations in the roll profile, including the possibility that the rolls flatten completely. However, these models require computationally expensive iterative solution techniques. A new approach to the approximate solution of the Fleck et al. (1992) Influence Function Model has been developed using both analytic and approximation techniques. The numerical difficulties arising from solving an integral equation in the flattened region have been reduced by applying an Inverse Hilbert Transform to get an analytic expression for the pressure. The method described in this paper is applicable to cases where there is or there is not a flat region.

A new low temperature synthesis route of fraipontite (Zn,Al)3(Si,Al)2O5(OH)4

A low temperature synthesis method based on the decomposition of urea at 90°C in water has been developed to synthesise fraipontite. This material is characterised by a basal reflection 001 at 7.44 Å. The trioctahedral nature of the fraipontite is shown by the presence of a 06l band around 1.54 Å, while a minor band around 1.51 Å indicates some cation ordering between Zn and Al resulting in Al-rich areas with a more dioctahedral nature. TEM and IR indicate that no separate kaolinite phase is present. An increase in the Al content however, did result in the formation of some SiO2 in the form of quartz. Minor impurities of carbonate salts were observed during the synthesis caused by to the formation of CO32- during the decomposition of urea.