Notes, abstracts, papers, exams and problems of Technology

Development and Implementation of Demolition

1. Dismantling of industrial equipment.
2. Demolition or removal of bodies and covered ledges.
3. Demolition or removal of the deck.
4. Demolition of elements at each plant: interior partition walls, curtain walls, and cargo.
5. Demolition of structural elements: forged with beams, reinforced concrete slabs (one-direction, two-directions), beams, brackets, domes.

Types of Demolition

According to Procedure

1. Element by element.
2. With collapse.
3. Mixed or combined.

According to Media

1. Manual.
2. Mechanical.
3. Thermal.
4. By explosives.

Design of a Sanitation Network

• If the network is public: Mixed.
• If two networks (wastewater and stormwater): Separator system.

Basic Sanitation Network Requirements

1. Dispose of water seal to prevent the passage of air.

Machines and Energy

Machines use energy to perform useful work.

Fossil Fuels

Fossil fuels, such as coal, oil, and natural gas, can be burned to release heat energy.

Nuclear Fuel

Nuclear fuel, including uranium and radioactive materials like plutonium, can undergo fission reactions to produce electricity.

Renewable Energy

Renewable energy sources were the first to be used historically, powering machines such as mills.

Water Wheel

A water wheel utilizes the energy of flowing water through a system of blades. It has various applications, such as grinding wheat to make flour.

• Wheels running low: These are the simplest type, with the bottom submerged. The force of the water current moves the wheel.
• Current average: This type of wheel is used when the current

Rigid Couplings

Rigid couplings are used when trees are on the same axis and do not change their position. There are several types:

• Flange Couplings: These are based on placing two flanges on the ends of the shafts so that when tightening the screws, the flanges are joined together.
• Clamp Couplings: These use a tapered internal conical piece that is compressed when tightening the screws, pressing the two pieces together.

Mobile Couplings

Mobile couplings are designed to accommodate some degree of misalignment or movement between shafts.

• Couplings with Gaskets: These absorb minor irregularities through elastic rotation and allow for very little misalignment.
• Universal or Cardan Joints: These transmit motion between two non-aligned trees.
• Homokinetic

Laying Ground Facilities Project

The process involves several key steps:

• Research
• Determination
• Design
• Calculation of resistance
• Computation step of crack on the outside of the installation
• Calculation of contact and step voltages inside the installation
• Checking
• Research
• Correction

Wenner Method

The Wenner method is the most used and recommended technique to measure the resistivity of the ground.

High Voltage Open Circuit Procedure

1. Open the switch.
2. Open the disconnectors.

High Voltage Circuit Closing Procedure

1. Close the disconnectors.
2. Close the switch.

Lockout or Interlock Device

A lockout or interlock device is the set of operations aimed at preventing the operation of a device and maintaining it in a given position.

Verification of Absence of Tension

It is necessary... Continue reading "Grounding Systems & Electrical Safety Procedures" »

Operation of Drive Elements, Control, and a Hydraulic System

Hydraulic Group

Generates hydraulic energy. A motor-driven pump converts energy. If the flow encounters resistance, there is pressure to fit in the pressure relief valve. Fluid drains back to the tank through a filter. The tank stores and conditions the oil.

Hydraulic Actuators

Converting hydraulic energy into mechanical energy. Conversion by rotating movement (hydraulic motor, which is at the pump's traverse), or linear movement cylinder.

Cylinders:

1. Single-acting
2. Double-acting
3. Special
4. Plunger (double-acting piston rod makes)
5. Differential (double-acting 2:1 ratio S side plunger rod side)
6. Equilibrated (dual stem)
7. Telescopic (short length, big race)

Valves

Responsible for controlling flow regulation... Continue reading "Understanding Hydraulic Systems: Actuators, Valves, and Control" »

What are Monomers and Polymers?

Plastics are formed by the combination of low molecular weight molecules called monomers. Polymers are formed by joining monomers.

• The union of monomers results in large molecules called polymers.

What is Polymerization?

Polymerization is a chemical reaction that joins monomers into large chains to build macromolecules called polymers.

Artificial vs. Synthetic Plastics

Artificial plastics are created by transforming natural materials. Synthetic plastics are created from materials such as oil and gas.

Thermoplastics vs. Thermosetting Plastics

Thermoplastics can be heated and molded multiple times. Thermosets can only be heated and molded once.

Plastic Applications

Thermoset Applications

• Phenol formaldehyde (PF) combined

Material Science Timeline

• 1769: Discovery of the steam engine (Watt)
• 1831: Discovery of the dynamo (Faraday)
• 1913: Popularization of stainless steel
• 1950: Discovery of silicones and first use in aircraft
• 1960: Perfection of silicon crystals (almost perfect purity)
• 1962: Discovery of the nickel and titanium alloy
• 1971: Presentation of soft contact lenses (Bausch & Lomb)
• 1983: First mobile phone
• 1991: First Web page

Second Industrial Revolution Key Points

• New production systems improve accelerated production.
• Amendment to the way we produce at all levels.
• Minimization of production costs.

Plastics: An Overview

Plastics are characterized by their plasticity, a property that allows them to be easily molded into the most convenient shapes. Their history began... Continue reading "Material Science Timeline and Innovations" »

Mechanisms

Mechanisms are devices that transmit motion to perform a job. They are used to transmit motion in two primary ways:

Linear Motion Transmission

1. Fixed Pulleys

   A fixed pulley is a wheel with a grooved edge that rotates around a central axis. A rope or belt passes through the groove. The force applied at one end of the rope equals the resistance at the other (F = R). The advantage of a fixed pulley is the change in the direction of motion.

2. Movable Pulleys

   In a movable pulley, one end of the rope is fixed, and the resistance hangs from the pulley's axle. The force required is half the resistance (F = R/2).

3. Pulley Systems (Hoists)

   A hoist combines fixed and movable pulleys. The force required is calculated as F = R/(2n), where 'n' is the number

Different Properties of Materials

The ability of a resistance material to resist forces without distorting excessively or breaking is a crucial property.

• Toughness

  Toughness is the property that some materials have to withstand forces repeatedly without breaking.

• Resilience

  Resilience is the property of a material to recover its original shape after being deformed by an effort.

• Ductility

  Ductility is the property of certain materials to deform permanently into a thin wire without breaking.

• Malleability

  Malleability is the property of certain materials to deform permanently in the form of a thin sheet without breaking.

• Hardness

  Hardness is the property that indicates the opposition a material offers to being penetrated or scratched.

Different Types of Stresses

• Traction

  Traction