lecture 3 Flashcards
The faster we mix alginates and gypsum, the less viscous and more fluid they become: psuedoplastic fluids
Not thixotropic; thixo is a subcategory of pseudoplastic
ye
Fluids that become more flowable upon repeated application of pressure are thixotropic fluids such as: synovial fluid in the TMJ
ye
what are the three dimensions of colour?
Hue: dominant color of an object
Value: relative darkness or lightness of a color (grey scale)
Will give a scale; if it gives a value of a peak of 0, you are looking at air; if it gives something else, you are looking at tissue
Radiology?
Chroma: degree of saturation of a specific hue
The amount of x-rays absorbed is a function of density and thickness of the material, and the energy of radiation
Phosphorous and metals with a higher atomic number are radiopaque
what are the types of corrosion?
- glavanic
- crevice
- pitting
- intergranular
- homogenous attack
- stress cracking corrosion
- fatigue corrosion
study slide 8
ye
passivisity = ability of a metal to resist corrosion due the formation of a surface oxide layer
ye
study slide 10
ye
young’s modulus?
stress/strain
shear modulus?
shear stress/shear strain, tau/gamma; tau = force/area, gamma = change in x/y (see slide 19)
Brittle materials like ceramics fracture at low tensile loads, but exhibit outstanding characteristics under compression because under compression, cracks close up rather than propagate
ye
study slide 20/22 (creep strain)
ye
what is fatigue?
Fatigue is the mechanical behaviur of a material stressed cyclically at levels below σy
what is endurance limit?
The endurance limit of a dental alloy (σel) increases with the decrease in grain size
To design a dental material for fatigue applications, stay under the (σel)
study slide 24
ye
