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Visar resultat 1 - 5 av 10 avhandlingar som matchar ovanstående sökkriterier.

1. 1. The long-term decline of the grey-sided vole (Clethrionomys rufocanus) in boreal Sweden: importance of focal forest patch and matrix

   Författare :Pernilla Christensen; Birger Hörnfeldt; Rolf A. Ims; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; : Destructive sampling; high quality habitat; focal habitat; landscape; habitat fragmentation; threshold; clear-cut; patch size and quality; long-term time-series; Terrestrial ecology; Terrestisk ekologi;

   Sammanfattning : There has been a long-term decline in number of cyclic vole populations in boreal Sweden since the 1970s. Several hypotheses have been suggested to explain this decline. Commonly for C. glareolus, C. LÄS MER

3. 2. Photonic Techniques for Real-Time Analog-to-Digital Conversion

   Författare :Johan Stigwall; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; tunable THz generation; photonic time-stretch; photonic sampling; Photonic analog-to-digital conversion; optical signal processin; photonic binary encoding; microwave photonics; photonic thresholding;

   Sammanfattning : All-electronic analog-to-digital conversion (ADC) technology is limited by the timing accuracy and inherent speed of semiconductor materials. Photonic techniques, however, can potentially enable real-time ADC at a considerably wider bandwidth, higher sample rate and/or resolution, thanks to the availability of extremely accurate optical clocks and the immense bandwidth of optical systems. LÄS MER

4. 3. Estimation of wood fibre length distributions from censored mixture data

   Författare :Ingrid Svensson; Sara Sjöstedt - de Luna; Lennart Bondesson; Aila Särkkä; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; censoring; fibre length distribution; identifiability; increment core; length bias; mixture; stochastic EM algorithm; Mathematical statistics; Matematisk statistik;

   Sammanfattning : The motivating forestry background for this thesis is the need for fast, non-destructive, and cost-efficient methods to estimate fibre length distributions in standing trees in order to evaluate the effect of silvicultural methods and breeding programs on fibre length. The usage of increment cores is a commonly used non-destructive sampling method in forestry. LÄS MER

5. 4. Experimental studies of materials migration in magnetic confinement fusion devices : Novel methods for measurement of macro particle migration, transport of atomic impurities and characterization of exposed surfaces

   Författare :Igor Bykov; Henric Bergsåker; Matej Mayer; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; fusion; tokamak; RFP; divertor; limiter; SOL; transport; migration; surface analysis; IBA; ion micro beam; beryllium; tritium; Physics; Fysik;

   Sammanfattning : During several decades of research and development in the field of Magnetically Confined Fusion (MCF) the preferred selection of materials for Plasma Facing Components (PFC) has changed repeatedly. Without doubt, endurance of the first wall will decide research availability and lifespan of the first International Thermonuclear Research Reactor (ITER). LÄS MER

7. 5. Application of the SASW-technique in geotechnical in-situ testing

   Författare :Mats Svensson; Institutioner vid LTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; teknisk geologi; Hydrogeologi; Spectral Analysis of Surface Waves; shear modulus; SASW; multichannel; inversion; Gmax; teknisk geografi; Environmental technology; pollution control; Miljöteknik; kontroll av utsläpp; geographical and geological engineering; Hydrogeology; Civil engineering; hydraulic engineering; offshore technology; soil mechanics; Väg- och vattenbyggnadsteknik;

   Sammanfattning : With the main aim to test the applicability of the surface wave seismic technique Spectral Analysis of Surface Waves (SASW), used for determination of the shear stiffness (shear modulus - Gmax), four areas of applications have been studied. The four areas have been sites with natural geological conditions, sites where non destructive testing is necessary, pavement testing and multichannel testing. LÄS MER