Search for dissertations about: "break-up event"

Showing result 1 - 5 of 8 swedish dissertations containing the words break-up event.

  2. 1. The flux of extraterrestrial matter to Earth as recorded in Paleogene and Middle Ordovician marine sediments

    Author : Anders Cronholm; Berggrundsgeologi; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; L-chondite; sediment-disperesed; chromite; break-up event; Arenig-Llanvirn;

    Abstract : This thesis aims at reconstructing events in the solar system, mainly collisional events in the asteroid belt, by searches for extraterrestrial minerals in Paleogene and Middle Ordovician marine sediments on Earth. Recent empirical evidence show that Earth has experienced a few brief periods during the Phanerozoic when the flux of extraterrestrial matter significantly increased. READ MORE

  4. 2. Traces in Earth's geological record of the break-up of the L-chondrite parent body 470 Ma

    Author : Carl Alwmark; Berggrundsgeologi; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; L chondrite; Middle Ordovician; extraterrestrial material; meteorite flux; Sweden;

    Abstract : This thesis deals with signatures in sediments on Earth related to the L-chondrite parent body break-up event at 470 Ma. The aim of this thesis is twofold: (1) investigate if the increased flux of extraterrestrial material to Earth, following the disruption of the L-chondrite parent body included larger, asteroid-sized bodies (2) try to develop new methods and tools for finding and classifying relict cosmic material in sediments. READ MORE

  5. 3. Fibre flocculation during twin-wire roll forming

    Author : Roger Bergström; KTH; []
    Keywords : ;

    Abstract : At the division of Paper Technology a forming unitconsisting of headbox, forming roll unit and reservoir systemfor suspension recirculation has been constructed, with themain purpose to experimentally study the paper forming event byvisually following the fibre flow phenomena in the formingzone.The effect of various running parameters upon the pressuredistribution, which is in correlation to the flow phenomenaoccuring during forming, has been studied with a flush mountedpressure sensor. READ MORE

  6. 4. Beyond a Second Demographic Transition? Fertility and family dynamics in Iceland

    Author : Ari Klængur Jónsson; Gunnar Andersson; Gerda Neyer; Daniele Vignoli; Stockholms universitet; []
    Keywords : SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Family demography; Fertility; Family formation; Cohabitation; Nonmarital childbearing; Marriage; Marital dissolution; Iceland; Demography; demografi;

    Abstract : This thesis serves to bring Iceland into the realm of Nordic family-demographic and fertility research. Based on event-history techniques applied to Iceland longitudinal register data, I provide an overview of contemporary family-demographic trends during the last few decades. The thesis consists of four empirical studies. READ MORE

  7. 5. Conodont biostratigraphy, taxonomy and palaeoecology in the Darriwilian (Middle Ordovician) of Baltoscandia - with focus on meteorite and extraterrestrial chromite-rich strata

    Author : Johanna Mellgren; Berggrundsgeologi; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Conodonts; biostratigraphy; taxonomy; palaeoecology; morphometrics; extraterrestrial chromite; meteorites; Darriwilian; Middle Ordovician; Baltoscandia;

    Abstract : This thesis deals with conodont biostratigraphy and palaeoecology in the Darriwilian (Middle Ordovician) of Baltoscandia, with focus on limestone strata showing traces of the ~ 470 Ma L-chondrite parent body break-up. The evidence for this cosmic event includes abundant centimeter to decimeter-sized fossil meteorites and elevated levels of sediment-dispersed extraterrestrial L-type chromite found in a stratigraphical interval corresponding to the uppermost Lenodus antivariabilis, the L. READ MORE