Technical Processes: Tunnel Boring, Diesel Engines, and Corrosion Control

Tunnel Boring Process

1. Cutting the Rock Surface. The face of the cutter rotates about seven times a minute, and the teeth cut large circles into the surface of the rock.
2. Collecting the Rocks. Pieces of the rock fall to the ground, and when the cutter face rotates upwards, the rocks fall onto conveyor belts.
3. Moving the Cutter. Hydraulic cylinders push the body of the cutter slowly forwards. The steel shoes move outwards and grip the tunnel walls, while two legs push down and lift the machine off the floor.
4. Supplying the Electricity. The power is connected to the cutters by means of a 13,800-volt cable.
5. Strengthening the Roof. When the machine moves forwards, holes are drilled into the roof of the tunnel, and then the holes are filled with bolts and cement.
6. Machine Operation and Monitoring. The machine operator sits in a cabin at the heart of the machine, where they control its speed and direction. Video cameras monitor the cutter and the tunnel.

How Diesel Engines Differ from Petrol Engines

Diesel engines differ from petrol engines in one key respect: when a mixture of diesel and air is compressed inside a hot cylinder, it will explode. A diesel engine must therefore work in a way which prevents the diesel from exploding before the piston is at the top of the cylinder.

The engine takes in only air during the intake stage of the cycle. Therefore, the air during the compression stage is pressurized. It is only when full compression has occurred that the fuel injector above each cylinder forces vaporized diesel into the combustion chamber.

Diesel engines operate at lower speeds than petrol engines. However, they are more able to power heavy vehicles as they can produce greater amounts of power than petrol engines.

Understanding and Preventing Metal Rusting

Rusting is a chemical process produced when water, oxygen molecules contained in the air, and iron mix. This mixture forms a layer of rust and weakens the metal.

Areas Commonly Affected by Rust

• Construction structures
• Train rails
• Ships
• Car chassis
• Other iron-based items

If rusting is superficial, we can clean it and prevent further damage by painting the metal. However, if the rusting has produced a gap in the metal, an accident could happen.

Rust Prevention Methods

In order to avoid the process, we can use different metals that self-protect from rusting, such as aluminum, stainless steel, copper, and other alloys. Finally, I would like to emphasize that rusting is produced in some materials we use daily, but we can prevent it by painting or replacing the metals.