Precision Measuring Tools and Their Applications
Combination Square
Inventor: Laroy Starrett invented the combination square in 1887.
The combination square is one of the most practical and versatile tool inventions worldwide – the basic tool of every builder and professional. As the name suggests, this instrument can be used for many different purposes. It replaces a full set of fixed brackets: mean square, depth gauge, height gauge, tracer gauge, level, and plumb. It can also be used as an accurate ruler by removing the blade. This prevents overloading
Read MoreMechanical Properties of Materials: Ferrous Metals & Testing
Mechanical Properties of Materials
Elasticity
The ability of a material to regain its original form after the deforming force is removed.
Plasticity
The ability of a material to retain its new shape after being deformed.
Ductility
The ability of a material to be stretched into threads or wires.
Malleability
The ability of a material to be spread into thin sheets.
Hardness
The resistance a material offers to being scratched or penetrated by another material (wear resistance).
Fragility
The tendency of a material
Read MoreAC Electrical Machines: Synchronous Motors
AC Electrical Machines
Synchronous Motors and Generators
AC electrical machines are classified into two main types:
- Synchronous motors and generators: The coil inductor current is supplied by a separate source of direct current (DC).
- Induction motors: The inductor winding current is provided by magnetic induction.
Differences Between AC and DC Machines
The location of the coils and inductors differs depending on the type of machine. In an AC machine, there is no electrical connection between the rotor
Read MoreRadiation Detectors: Geiger Counters, Cloud Chambers, and More
Radiation Detectors: A Detailed Look
Geiger Counter
A Geiger counter consists of a central wire inside a hollow metal cylinder filled with gas at low pressure. An electrical voltage is applied between the cylinder and the wire, making the wire more positive than the cylinder. When radiation enters the tube and ionizes an atom in the gas, the released electron is attracted towards the positively charged central wire.
As the electrons accelerate toward the wire, they collide with other atoms, releasing
Read MoreTouchscreen Technologies: Ultrasonic, Near Field, and Standards
Touchscreen Technologies and Display Standards
Ultrasonic Touchscreen Technology
Used technology: Ultrasonic transducers generate surface waves transmitted through the glass surface and received by sensors on the opposite side. A pointer touching the screen absorbs some acoustic wave energy. The receiver measures changes in the received acoustic wave’s amplitude to detect the pointer’s position.
Advantages
- Total light transmission
- Protection through a graphical display
- Ability to detect the depth of the
Metal Cutting Principles: Forces, Tool Wear, and Operations
Cutting Forces and Temperatures
The chip consists of a plastically deformed workpiece. The plastic deformation of the cut layer occurs under the action of a force which must be greater than the resistance of the metal to deformation and destruction.
Temperature: Heat is released during the cutting process as the cut layer is deformed and frictional processes take place in the cutting area. Almost all mechanical work (about 99%) to cut the chip is converted into heat, so the temperature during cutting
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