Sökning: "background inertia"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden background inertia.

  1. 1. Dynamic neck formation in elastic-plastic tensile bars

    Författare :Kristina Nilsson; Lund University.; Lunds universitet.; [2000]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; dynamic loading; necking; inertia; localization zones; numerical simulation; finite elements; non-linear;

    Sammanfattning : The time development of neck formation in ductile elastic-plastic bars is analyzed numerically in order to obtain a qualitative description of the features of dynamic neck localization under impact conditions. The full time history is visualized using contour plots of the time development of a strain rate parameter. LÄS MER

  2. 2. Simulation of dynamic instabilities during high rate deformation of ductile bars and plates

    Detta är en avhandling från Division of Mechanics, Lund University

    Författare :Kristina Nilsson; Lund University.; Lunds universitet.; [2005]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; numerical simulation; non-linear; wave propagation; multiple necking; necking; buckling; fracture; Mechanical engineering; Maskinteknik; finite elements; cohesive elements; dynamic; J2-flow theory; J2-deformation theory; viscoplastic; background inertia;

    Sammanfattning : In this thesis, some of the phenomena occurring in plates and cylindrical bars subjected to dynamic loading are investigated. Numerical simulations using a dynamic finite element code are performed for a number of different sized specimens with various initial surface imperfections. Typically imposed loading velocities are in the range 10m/s.. LÄS MER

  3. 3. Nitrogen land-sea fluxes in the Baltic Sea catchment Empirical relationships and budgets

    Detta är en avhandling från Stockholm : Department of Applied Environmental Science (ITM)

    Författare :Hanna Eriksson Hägg; Stockholms universitet.; [2010]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nitrogen fluxes; Baltic Sea; primary emissions; riverine export; Scenario analysis; climate change; animal protein consumption; fertilizer use; NATURAL SCIENCES Chemistry Environmental chemistry; NATURVETENSKAP Kemi Miljökemi; tillämpad miljövetenskap; Applied Environmental Science;

    Sammanfattning : In this thesis empirical relationships and modeling tools are used to describe the relationship between human activities and meso- and large scale riverine N fluxes from land to sea.On a large scale Paper I showed that by only having knowledge about human population size and runoff one can estimate the riverine export of DIN (r2= 0.76). LÄS MER

  4. 4. Service life estimations in the design of a PCM based night cooling system

    Detta är en avhandling från Stockholm : KTH

    Författare :Göran Hed; Högskolan i Gävle.; KTH.; [2005]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TECHNOLOGY Civil engineering and architecture Building engineering; TEKNIKVETENSKAP Samhällsbyggnadsteknik och arkitektur Byggnadsteknik; TECHNOLOGY Civil engineering and architecture Building manufacturing engineering; TEKNIKVETENSKAP Samhällsbyggnadsteknik och arkitektur Byggproduktionsteknik;

    Sammanfattning : The use of Phase Change Material, PCM, to change the thermal inertia of lightweight buildings is investigated in the CRAFT project C-TIDE. It is a joint project with Italian and Swedish partners, representing both industry and research. PCMs are materials where the phase change enthalpy can be used for thermal storage. LÄS MER

  5. 5. Severe asphyxia due to substandard care during labour

    Detta är en avhandling från Stockholm : Karolinska Institutet, Department of Clinical Science and Education, Södersjukhuset

    Författare :Sophie Berglund; Karolinska Institutet.; Karolinska Institutet.; [2010]
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Asphyxia; Apgar score; labour; delivery; oxytocin; vacuum extraction; Caesarean section; substandard care; medical malpractice; cerebral palsy; neonatal resuscitation; perinatal death; neonatal death; fetal blood sampling; CTG; FHR;

    Sammanfattning : Aim The objective of the thesis was to describe the most common causes of substandard care during labour contributing to severe asphyxia or neonatal death, to study risk factors related to asphyxia associated with substandard care and to explore the occurrence of substandard care during labour. Background There are about 100 000 infants born every year in Sweden. LÄS MER