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Questions and Answers
What is the primary indication of setting time?
What is the primary indication of setting time?
What is the relationship between setting time and the completion of a reaction?
What is the relationship between setting time and the completion of a reaction?
What happens to the material after it reaches its setting time?
What happens to the material after it reaches its setting time?
What is the primary characteristic of a material that has reached its setting time?
What is the primary characteristic of a material that has reached its setting time?
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What is the implication of a material's setting time on its usage?
What is the implication of a material's setting time on its usage?
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What is the primary difference between setting time and the completion of a chemical reaction?
What is the primary difference between setting time and the completion of a chemical reaction?
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What is the significance of setting time in materials science?
What is the significance of setting time in materials science?
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What happens when a material reaches its setting time?
What happens when a material reaches its setting time?
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What is the primary difference between adsorption and absorption?
What is the primary difference between adsorption and absorption?
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What is the term that encompasses both adsorption and absorption?
What is the term that encompasses both adsorption and absorption?
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In which of the following processes do molecules penetrate the bulk of the material?
In which of the following processes do molecules penetrate the bulk of the material?
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What is the primary location where adsorption takes place?
What is the primary location where adsorption takes place?
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What is the key characteristic that distinguishes adsorption from absorption?
What is the key characteristic that distinguishes adsorption from absorption?
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Which of the following is NOT a characteristic of absorption?
Which of the following is NOT a characteristic of absorption?
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What is the relationship between sorption and adsorption?
What is the relationship between sorption and adsorption?
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Which of the following is an example of a process that is characterized by sorption?
Which of the following is an example of a process that is characterized by sorption?
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Study Notes
Material Properties
- As the force increases, the crack grows until it reaches the other surface, causing complete fracture of the sample.
Hardness
- Measures the ease of cutting, finishing, and polishing a material
- Also indicates scratch resistance
- Various hardness tests exist, including:
- Brinell
- Rockwell
- Barcrol
- Shore A
- Knoop
- Vickers (most common)
- Each test uses a different indenter, a piece of diamond with a specific geometric shape (e.g., sphere, rhomboidal pyramid, square pyramid)
- Each material has its own unique hardness number, determined by the load applied
Surface Energy and Wettability
- Surface energy is the sum of all intermolecular forces on a material's surface
- Contact angle is the angle between a liquid drop and a smooth surface, indicating wettability
- Important in dentistry, as it affects the color matching of fillings under different light sources
Setting Time
- The time required for a material to set or harden from a plastic or fluid state
- Does not indicate the completion of the reaction, but rather when the material can no longer be used
Material Properties
- Toughness is the resistance of a material to fracture, indicating the amount of energy required to cause fracture or break a material.
Fracture Toughness
- Fracture Toughness (KIC) measures the energy consumed in plastic deformation.
- The Fracture Toughness test involves applying a force onto a sample with a specific morphology, such as a notch or crack, to measure the energy required to cause fracture.
Abrasive Wear
- Abrasive wear occurs through two-body wear, where direct sliding action occurs between antagonistic objects with no intermediate layer transmitting forces between the interlocking surfaces.
Rheological Properties
- Viscosity is the resistance of a fluid to flow, measured as shear stress/strain.
- The unit of viscosity is Poise (1 P = 0.1 Pa-s), or Centipoise (100 cP = 1P).
- Types of viscous fluids can be classified according to their flow behavior:
- Newtonian fluids: viscosity is constant and independent of stress rate.
Sorption
- Sorption is a general term that describes both adsorption and absorption.
- Adsorption involves molecules being taken up by the surface, whereas absorption involves molecules being taken up by the volume.
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Description
This quiz explores the concept of material fracture when subjected to increasing force, resulting in cracks and eventual breakage.
