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

Properties of Metals

PROPERTIES OF METALS: good electrical, thermal and acoustic conductors; ductile and malleable; tough; they melt at high temperatures, expand when the temperature rises and contract when it cools; some are magnetic; rust when they come into contact with air and oxygen (not all); can be recycled and reused, some are toxic for the environment.

Ferrous Metals

FERROUS METALS: main component is iron.

PURE IRON: greyish white colour, good magnetic properties. Disadvantages: only melts at high temperature, difficult to machine, fragile and brittle. Uses: rarely used, used in electronics and electrical components. CAST IRON: very hard and resistant. Uses: machine parts, casing for engines, stands for machines, pistons, street lamps,... Continue reading "Properties of Metals and Ferrous vs. Non-Ferrous Metals" »

Function Definition

A function definition in C++ consists of the statements that constitute a function. It includes:

• Name: The identifier of the function.
• Parameter List: Variables enclosed in parentheses that hold values passed to the function.
• Body: Statements within curly braces that perform the function's task.
• Return Type: The data type of the value the function returns (e.g., int, double, void if no value is returned).

Function Header

The function header declares the function. It consists of:

• Return Type
• Name
• Parameter List

For example: void evenOrOdd(int num). Note that there is no semicolon at the end of the header.

Function Return Type

• If a function returns a value, the return type must be specified (e.g., int main()).
• If a function doesn't return

What is Injection Molding?

Injection molding is a manufacturing process for producing parts in large volumes. It is most typically used in mass-production processes where the same part is being created thousands or even millions of times in succession.

Injection Molding Machine

Why Use Injection Molding?

The principal advantage of injection molding is the ability to scale production en masse. Once the initial costs have been paid, the price per unit during injection molded manufacturing is extremely low. The price also tends to drop drastically as more parts are produced. Other advantages include the following:

• Molding is very repeatable. That is, the second part you produce is going to be practically identical to the first one. This is a wonderful

Pre-Flight & Taxi Procedures

Before Taxi

• Pitot Heat: Check
• Ammeter: Check rise
• Taxi Clearance: As Required
• Altimeter: Set and check
• Transponder: Set code
• Propeller: Full forward
• Area: Clear

Taxi

• Throttle: Idle
• Parking Brake: Release
• Landing Light: On
• Brakes: Check
• Steering: Check
• Flight Instruments: Check
• Takeoff Brief: Perform

Takeoff & Climb Procedures

Takeoff

• Area Ahead: Clear
• Transponder: ALT
• Strobe & Landing Lights: On
• Fuel Pump: On
• Propeller: Full forward
• Mixture: Full forward
• Flaps: Set
• Trim: Takeoff setting
• Directional Gyro: Set
• Takeoff Clearance: Received
• Throttle: Full forward
• Engine Gauges: Check

After Takeoff

• Brakes: Apply
• Gear: Up
• Airspeed: Refer to table
• Flaps: Up
• Throttle: Full forward
• Propeller: 2700 RPM
• Landing Light: Off
• Fuel Pump: On
• Engine Gauges:

Understanding Electrical Safety and Protection

The physiological effects and after-effects of electric current are determined by several critical factors:

• Type of current
• Current magnitude
• Frequency
• Duration of current passing through the body
• Resistance of the human body
• The insulation properties of the skin

Conductor Identification: Notation and Colors

Proper identification of conductors is crucial for electrical safety. Here are the standard notations and colors for insulated conductors:

• Working Conductor: Wire of the current system for power supply and energy transmission. Colors: Black, Brown, and Grey.
• Neutral Conductor: Wire connected to the source node, which contributes to energy transmission. Color: Light Blue.
• Protective Conductor: Wire required

Computer Fundamentals

Basic Computer Scheme

Input, Process, Output.

Binary Code

Information in a PC is processed using binary code.

RAM (Random Access Memory)

A type of data storage generally located on the motherboard. It is volatile; all information is lost when the computer turns off.

ROM (Read-Only Memory)

A non-volatile memory used in computers and other electronic devices.

CPU (Central Processing Unit)

The brain of the computer where most calculations take place. The CPU is the most important part of a computer system.

Motherboard

The physical arrangement in a computer that contains all the computer's components.

Analog vs. Digital Technology

In analog technology, information is translated into electric pulses of varying amplitude. In digital technology,... Continue reading "Computer Fundamentals and Internet Connections" »

Home Automation and Telecommunication

Home Automation

Home Automation refers to the use of computer and information technology to control a home. This includes various aspects such as:

• HVAC (Heating, Ventilation, and Air Conditioning): Controls the temperature and air quality in your home.
• Lighting: Allows you to control lights remotely and automate lighting schedules.
• Intercom: Enables communication within the home or with visitors at the door.
• Smart Window: Windows that can be automatically tinted or adjusted for optimal energy efficiency.
• Video Door Phone System: Allows you to see and communicate with visitors at your door remotely.
• Socket: Smart sockets that can be controlled remotely and monitor energy usage.
• TV Set: Integration with smart TVs

parallel circuits

Mechanisms

Mechanisms are devices that transform movement. They can change the speed, direction, force, or type of movement.

Belts and Pulleys

A belt passes around two pulley wheels. If the driver wheel moves, it moves the belt, and the belt moves the driven wheel.

A pulley is a wheel that turns when a rope, belt, or chain passes through it.

Levers

The lever is a basic mechanism. It's typically made of a bar of wood or metal that pivots around a fixed point called a fulcrum.

• First-type lever Examples: Scissors, pliers, bottle opener, seesaw.
• Second-type lever Examples: Wheelbarrow, paint chippers, nutcrackers.
• Third-type lever Examples: Catapult, baseball bat, human arm.

Effort x Effort arm = Load x Load arm

Questions about levers and pulleys

1. What does

Mechanisms

A mechanism is a group of elements that transmit and transform forces and movements from a motive (or driver) element to a receptor (or driven) element. Mechanisms allow us to perform operations more easily and with less effort.

Classification of Mechanisms

• Movement Transmission Mechanisms
  • Linear Transmission (e.g., pulleys, levers)
  • Circular Transmission (e.g., friction wheels, pulleys and belts, gears, chain drives)
• Movement Transformation Mechanisms (e.g., rack and pinion, handle-winch, crank-connecting rod, cam and eccentric)

Lever

A lever is a rigid bar that pivots around a fixed point called a fulcrum. It is used to amplify force, allowing a larger force to be overcome with a smaller effort. However, to achieve this force multiplication,... Continue reading "Mechanisms: Levers, Pulleys, Gears, and More" »