Notes, summaries, assignments, exams, and problems for Technology

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" »

Technology Project Process and Building Materials

Technology Project Process

• Problem Analysis

  Tools for analysis, potential improvements, relevant knowledge, ideas, and theories.

• Technical Project

  • Idea Generation

    Each participant creates a sketch or drawing with a brief explanation detailing the object, its components, and operation.

  • Idea Selection

    Choose the most appropriate idea based on criteria such as potential for improvement, feasibility with available resources, frequency of suggestion, or innovative solutions to the problem.

  • Final Design

    Create detailed drawings, plans, and views of the object.

  • Material Selection

    Choose appropriate materials for each part considering technical, aesthetic, economic, and ecological factors, utilizing available resources.

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

Electrical Protection Devices

Protection devices safeguard electrical installations and connected components from potential overloads. They also protect people from electric shock, preventing current leakage to the ground and the consequent economic damage to the user.

Fuses

A fuse is connected in series with the circuit so that all the current flows through it. It consists of a base with two fixed contacts, a plug-piece cartridge or blade, and fusible material surrounded by a medium that acts as a means of extinction.

• Overload: Occurs when the current value in an electrical installation exceeds the fuse's rating.
• Short circuit: Occurs when a fault in an installation element or an accident causes a sudden surge in current, causing the fuse to blow.

DVD Data Storage

The DVD data zone consists of a highly reflective layer called the land. Projections known as pits rise from this land. These pits represent recorded data. The data track is recorded helically from the inside to the outside of the disc.

Pixelated Images and Freezing

If a DVD player displays pixelated images and freezes with different discs, the first step is to clean the lens.

DVD Photodetector Composition and Function

(Information needed)

DVD Servo Systems

DVD players have five servo systems:

1. Focus Control
2. Track Monitoring
3. Coil Monitoring (Tracking)
4. Sled Servo
5. Disc Speed Control

Symptoms of a Dirty Lens and Cleaning Procedure

A dirty lens can cause various playback issues. Here's how to clean it:

1. Moisten one end of a cotton swab with isopropyl

1. LAN Design Constraints

   Answer: The main constraints when designing Local Area Networks (LANs) include economy, geographical extension, the number of people, and call habits.

2. Subscriber Circuit Length Limits

   Answer: Parameters that limit the length of the subscriber circuit are attenuation limits, the signaling driver, and resistance.

3. Benchmark Frequencies: Europe & USA

   Answer: The high benchmark frequencies are 1000Hz (USA) and 800Hz (Europe).

4. Subscriber Circuit Design Criteria

   Answer: The basic criteria that apply to the design of subscriber circuits are signaling, attenuation, and resistance.

5. Electrical Resistance Formula

   Answer: The formula for calculating the electrical resistance of a conductor is: R = ρL/A (where R is resistance, ρ is resistivity,