Sökning: "Impact"

Visar resultat 6 - 10 av 10353 avhandlingar innehållade ordet Impact.

1. 6. Terrestrial consequences of hypervelocity impact – shock metamorphism, shock barometry, and newly discovered impact structures

   Författare :Sanna Alwmark; Berggrundsgeologi; []
   Nyckelord :Impact cratering; Impact structure; Shock metamorphism; Shock barometry; Quartz; Planar deformation features; Siljan; Målingen; Hummeln;

   Sammanfattning : Impact cratering was once considered a rare geological process of no, or little, importance to the evolution of the Solar System and planet Earth. After more than 50 years of space exploration and the discovery of numerous (~190 as of October 2016) impact structures on Earth, this view has changed, and it is now clear that impact craters are in fact one of the most common morphological features on solid bodies in the Solar System. LÄS MER

3. 7. Damage Tolerance of Impacted Composite Sandwich Structures

   Författare :Moeen ud din Saeed Rajput; Malin Åkermo; Stefan Hallström; Magnus Burman; Christian Berggreen; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; composite sandwich; cellular; polymer; material characterization; modulus; non-crimp fabric; low velocity impact; vibration; uncertainty analysis; drop-weight impact; fractography; barely visible impact damage; X-ray microtomography; compression-after-impact; bending-after-impact; high speed image processing; damage resistance; damage tolerance; Aerospace Engineering; Flyg- och rymdteknik;

   Sammanfattning : This thesis deals with damage tolerance of impacted sandwich structures for load bearing applications. Composite sandwich structures find wide application as lightweight solutions in aerospace components, since weight reduction and less fuel emissions are primary concerns for aircraft manufactures. LÄS MER

4. 8. Two problems of viscoelastic impact : prediction of impact force and identification of complex modulus

   Författare :Sven Ödeen; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Hållfasthetslära; Solid Mechanics;

   Sammanfattning : .... LÄS MER

5. 9. Two-Dimensional Signal Root Estimation in Blind Multichannel Impact Response Analysis

   Författare :Joakim Axmon; Matematisk statistik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; forestry; Silviculture; detection of decay.; Norway spruce; X-texture mode; signal subspace enhancement; partial forward-backward averaging; ESPRIT; state-space; Prony; frequency analysis; SIMO; impact response; Modal analysis; impact excitation; forestry technology; Skogsvetenskap; skogsbruk; skogsteknik; Electrical engineering; Elektroteknik; Signal processing; Signalbehandling;

   Sammanfattning : This doctoral dissertation concerns two-dimensional frequency estimation for modal analysis of single-input multiple-output impact responses from circularly cylindrical objects. The application is within detection of internal defects in trunks of spruce. LÄS MER

7. 10. Assessing mathematical creativity : comparing national and teacher-made tests, explaining differences and examining impact

   Författare :Jesper Boesen; Johan Lithner; Torulf Palm; Gunnar Gjone; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Mathematical reasoning; creative reasoning; moderate high stake; teacher made tests; imitative reasoning; assessment; impact; influence; effect; mathematical competence; national tests; MATHEMATICS; MATEMATIK; Mathematical reasoning; creative reasoning; moderate high stake; teacher made tests; imitative reasoning; assessment; impact; influence; effect; mathematical competence; national tests;

   Sammanfattning : Students’ use of superficial reasoning seems to be a main reason for learning difficulties in mathematics. It is therefore important to investigate the reasons for this use and the components that may affect students’ mathematical reasoning development. LÄS MER