301 resultados para ultra-som intravascular


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Avhandlingens primära syfte är att upprätta en förståelse för visuell kompetens som en del av visuell litteracitet inom multimodal digital kommunikation i undervisningen. Avhandlingens sekundära syfte är att ur ett pedagogiskt perspektiv lyfta fram visuell litteracitet och visuell kompetens i multimodala diskussioner kring digital pedagogik. Forskningen är kvalitativ och har både teoretisk och empirisk förankring. Den empiriska studien har en fenomenologisk metodansats. Visuell kompetens innebär att visuell läsning behärskas, vilket förutsätter fungerande vokabulär, kritiskt förhållningssätt och kunskaper i läsning och tolkning och användning av bilder. Den visuella grammatikteorin innefattar bildens syntax och semantik. Bilden är ett kontextbundet fenomen, där kontexten berör sociala aspekter, bildens fysiska omgivning samt innehåll. Det empiriska resultatet är att visuell inverkan i undervisningen präglar förberedelser och lektionsmål, berör visuell kommunikationskompetens, inkluderar visuella element som verktyg, strävar involvera flera element i inlärningen och strävar efter att undvika passiva demonstrationer som undervisningsmetod. Bilder behövs som kommunikativt stöd, som inlärningsmetod och som en del i aktivitetspedagogisk undervisning. Genom stöd från läraren kan barnet nå visuell litteracitet som ett kompetensmål, vilket kan ske genom multimodal undervisning.

Relevância:

20.00% 20.00%

Publicador:

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The aim of this work was to calibrate the material properties including strength and strain values for different material zones of ultra-high strength steel (UHSS) welded joints under monotonic static loading. The UHSS is heat sensitive and softens by heat due to welding, the affected zone is heat affected zone (HAZ). In this regard, cylindrical specimens were cut out from welded joints of Strenx® 960 MC and Strenx® Tube 960 MH, were examined by tensile test. The hardness values of specimens’ cross section were measured. Using correlations between hardness and strength, initial material properties were obtained. The same size specimen with different zones of material same as real specimen were created and defined in finite element method (FEM) software with commercial brand Abaqus 6.14-1. The loading and boundary conditions were defined considering tensile test values. Using initial material properties made of hardness-strength correlations (true stress-strain values) as Abaqus main input, FEM is utilized to simulate the tensile test process. By comparing FEM Abaqus results with measured results of tensile test, initial material properties will be revised and reused as software input to be fully calibrated in such a way that FEM results and tensile test results deviate minimum. Two type of different S960 were used including 960 MC plates, and structural hollow section 960 MH X-joint. The joint is welded by BöhlerTM X96 filler material. In welded joints, typically the following zones appear: Weld (WEL), Heat affected zone (HAZ) coarse grained (HCG) and fine grained (HFG), annealed zone, and base material (BaM). Results showed that: The HAZ zone is softened due to heat input while welding. For all the specimens, the softened zone’s strength is decreased and makes it a weakest zone where fracture happens while loading. Stress concentration of a notched specimen can represent the properties of notched zone. The load-displacement diagram from FEM modeling matches with the experiments by the calibrated material properties by compromising two correlations of hardness and strength.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Strenx® 960 MC is a direct quenched type of Ultra High Strength Steel (UHSS) with low carbon content. Although this material combines high strength and good ductility, it is highly sensitive towards fabrication processes. The presence of stress concentration due to structural discontinuity or notch will highlight the role of these fabrication effects on the deformation capacity of the material. Due to this, a series of tensile tests are done on both pure base material (BM) and when it has been subjected to Heat Input (HI) and Cold Forming (CF). The surface of the material was dressed by laser beam with a certain speed to study the effect of HI while the CF is done by bending the specimen to a certain angle prior to tensile test. The generated results illustrate the impact of these processes on the deformation capacity of the material, specially, when the material has HI experience due to welding or similar processes. In order to compare the results with those of numerical simulation, LS-DYNA explicit commercial package has been utilized. The generated results show an acceptable agreement between experimental and numerical simulation outcomes.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Julkaisutiedot kolofonista.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Julkaisutiedot kolofonista.