Search for dissertations about: "Mixture quality"

Showing result 16 - 20 of 145 swedish dissertations containing the words Mixture quality.

  2. 16. Mixture toxicity of pesticides and biological effects in agricultural streams : field and laboratory studies

    Author : Jenny Rydh Stenström; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : The main objective of this thesis was to examine pesticide mixture toxicity and its effects on aquatic biota in agricultural streams. This was accomplished by (1) calculating the ΣTUs for algae and Daphnia magna and a pesticide toxicity index (PTI) based on water quality standards (WQS) for long-term monitoring data (2002-2010), (2) by performing algal inhibition tests with Pseudokirchneriella subcapitata, using both collected in situ water samples and reconstituted water spiked with field-observed pesticide mixtures, and (3) by studying seasonal changes in macroinvertebrate and diatom communities during 2008 in four agricultural streams and determine a set of community-based metrics such as species richness, diversity, ASPT, SPEAR and IPS. READ MORE

  4. 17. Methods for longitudinal brain imaging studies with dropout

    Author : Tetiana Gorbach; Xavier de Luna; Anders Lundquist; Martin A. Lindquist; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Missing data; nonignorable dropout; sensitivity analysis; uncertainty intervals; pattern-mixture models; aging; cognition; MRI; brain structure; resting-state functional connectivity; Statistics; statistik;

    Abstract : One of the challenges in aging research is to understand the brain mechanisms that underlie cognitive development in older adults. Such aging processes are investigated in longitudinal studies, where the within-individual changes over time are observed. However, several methodological issues exist in longitudinal analyses. READ MORE

  5. 18. Reliability-based Design Procedure for Flexible Pavements

    Author : Yared Hailegiorgis Dinegdae; Björn Birgisson; Nicole Kringos; Nils Rydén; William Buttlar; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Top-Down fatigue cracking; asphalt mixture morphology; fracture mechanics; response surface; reliability analysis; load resistance factor design; Byggvetenskap; Civil and Architectural Engineering;

    Abstract : Load induced top-down fatigue cracking has been recognized recently as a major distress phenomenon in asphalt pavements. This failure mode has been observed in many parts of the world, and in some regions, it was found to be more prevalent and a primary cause of pavements failure. READ MORE

  6. 19. Coding Speech for Packet Networks

    Author : Jonas Lindblom; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; packet loss concealment; voice over IP; speech coding; harmonic modeling; vector quantization; sinusoidal modeling; Gaussian mixture modeling; bounded support; frame erasure; variable dimension;

    Abstract : The topic of this thesis is speech coding for packet networks. Problems related to the use of packet networks for voice communication are addressed. Real-time voice communication is for example very delay sensitive; if the total end-to-end delay in a telephone session grows large, it is perceived as annoying. READ MORE

  7. 20. Volatile organic compounds from microorganisms : identification and health effects

    Author : Anna-Sara Claeson; Anna-Lena Sunesson; Jan-Olof Levin; Steven Nordin; Bengt Järvholm; Charles Weschler; Umeå universitet; []
    Keywords : microorganisms; building materials; VOCs; MVOCs; amines; LC-MS MS; exposure; perceived air quality; Occupational and Environmental Medicine; arbets- och miljömedicin;

    Abstract : Damp building materials are subjected to degradation processes due to moisture and also microbial growth, with both of these giving rise to emissions of volatile organic compounds (VOCs) that may contribute to indoor air health problems. The overall aim of this thesis was to investigate emissions of reactive and non-reactive VOCs from damp building materials and from the microorganisms growing on them, and also to investigate the possible health impact of these compounds. READ MORE