Sökning: "nature cycles"

Visar resultat 6 - 10 av 73 avhandlingar innehållade orden nature cycles.

  1. 6. Terrestrial response to Dansgaard-Oeschger cycles and Heinrich events : the lacustrine record of Les Echets, south-eastern France

    Författare :Daniel S. Veres; Barbara Wohlfarth; John J. Lowe; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; lake sediments; palaeoclimate; organic matter; Dansgaard-Oeschger cycles; Heinrich events; MIS 3; Western Europe; Quaternary geology; Kvartärgeologi; Quarternary Geology; kvartärgeologi;

    Sammanfattning : Marine Isotope Stage (MIS) 3 was an interval characterized by large and abrupt temperature changes on a millennial time scale, the so-called Dansgaard-Oeschger (DO) cycles and Heinrich events. Evidence for this high-frequency climate variability has been identified in many marine and ice core records. LÄS MER

  2. 7. Thermodynamic Cycles using Carbon Dioxide as Working Fluid : CO2 transcritical power cycle study

    Författare :Chen Yang; Lundqvist Per; Carlos Infante Ferreria; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : The interest in utilizing the energy in low‐grade heat sources and waste heat is increasing. There is an abundance of such heat sources, but their utilization today is insufficient, mainly due to the limitations of the conventional power cycles in such applications, such as low efficiency, bulky size or moisture at the expansion outlet (e.g. LÄS MER

  3. 8. System Capability Feedback-Cycles in Automotive Software Development

    Författare :Magnus Ågren; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Continuous Software Engineering; Automotive Systems Engineering; Requirements Engineering; Software Architecture;

    Sammanfattning : Context: The automotive industry is currently going through rapid change, driven by new technology; for example, electrification, autonomous driving, and connected cars. This new technology is largely based on electronics and software, and vehicles are increasingly becoming software-intensive systems. LÄS MER

  4. 9. Efficiency Analysis of Drive-train for an Electrified Vehicle

    Författare :Ali Rabiei; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Drive cycles; Current vector control; Vehicle applications; Silicon carbide; Power electronics; Energy efficiency; Loss calculation; Electric machines;

    Sammanfattning : In this PhD thesis, various solutions to improve the energy efficiency in the electrical drive-train of an electrified vehicle such as modifications of the propulsioninverter or control of the electric machine, are proposed and their benefits arequantified from an energy efficiency point of view. The efficiency analysis isbased on modeling of a power electronics inverter, an electric machine and a battery in various drive cycles for an electrified vehicle. LÄS MER

  5. 10. Nonlinear and Nonparametric Dynamical Methods in Economics and Finance

    Författare :Gazi Salah Uddin; Bo Sjö; Ramo Gencay; Linköpings universitet; []
    Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Commodity markets; Nonlinear causality testing; Dependence structure; Business cycles; Timescale analysis; Growth dynamics; Portfolio management;

    Sammanfattning : The objectives of the thesis - which comprises six parts – can be summarized in i) implementing linear and nonlinear/nonparametric approaches toward detecting, measuring and analyzing the nature and directionality of causal relationships in financial markets, ii) elaborating on modern topics in financial investment analysis, iii) probing into the role of commodity futures in constructing optimal portfolios as well as iv) investigating growth dynamics via aggregated and disaggregated indices.The first paper named “Analyzing causal interactions between sectoral equity returns and commodity futures returns in the aftermath of the global financial crisis: The case of the US and EU equity returns”, aims to explore and compare the dependence and co-movement structure between commodity and various asset classes’ returns including the USA and EU stock markets via the use of linear and non-linear causality testing in a comparative context with the additional adjustment for cointegration and conditional heteroscedasticity. LÄS MER