Notes, summaries, assignments, exams, and exercises for Technology for Baccalaureate

Sawing and Drying

Performed in mills or sawmills, this process requires the following steps:

• Peeling: Removing bark to eliminate external and internal impurities.
• Parting: Cutting to the appropriate length and thickness.
• Drying: The final operation, which can be performed outdoors or under sheds to protect the wood from direct sunlight or rain.

Cutting Techniques for Timber

At the end of the milling process, each log is processed to obtain the maximum amount of marketable timber. Cutting techniques depend on:

• The characteristics of the trunk being used.
• The implementation of standard measures for various cuts.
• Customer needs and requirements.

Common cutting methods include: sawn into boards, barracks sawing, coastal sawing, and mesh sawing.

Surface Wood

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...

Thermal Machines and Energy Conversion

Thermal machines are systems designed to transform thermal energy into mechanical energy or vice versa.

Classification of Thermal Machines

External Combustion Engines

• Alternative: Steam engines utilizing single and double-effect mechanisms.
• Rotary: Closed-cycle systems such as steam turbines.

Internal Combustion Engines

• Alternative: Otto engines (4-stroke and 2-stroke) and Diesel engines (4-stroke and 2-stroke).
• Rotary: Wankel engines, open-cycle turbines, and gas turbines.

Heat Engine Fundamentals

A heat engine is a motor machine that converts thermal energy or heat into mechanical energy. In internal combustion machines, the fuel burns inside the machine, and the produced gases are responsible for driving the...

Local Area Networks (LAN)

A Local Area Network (LAN) consists of computers interconnected via cables to share resources and information. A cable connection is established through a network card, and computers must utilize network software to share connected devices. The TCP/IP protocol is used, and each computer is identified by a unique IP address.

Network Topologies

• Ring Network: Computers are connected in a closed loop. Information travels in a ring; each computer analyzes if it is the recipient, otherwise, it passes the information to the next node.
• Star Network: Computers are not directly linked but connect through a specific device:
  • Hub: Network cables from each computer reach the hub. The hub receives data and forwards it to the recipient,

Mechanical Power Transmission Systems

Shafts and Couplings

A shaft is a rotating machine element that transmits power or energy. A shaft can also be cylindrical and support rotating parts without transmitting power. Couplings connect two shafts:

• Rigid Coupling: Shafts are aligned and maintain their position during rotation (using flanges and couplings).
• Flexible Coupling: Allows for slight misalignment between shafts during operation.

Gear Trains and Powertrains

A gear train refers to a pair of meshing gears. A powertrain consists of two or more gear pairs that alter the rotational speed of the final shaft.

Joints

Joints transmit motion and forces. These forces can be in opposite, same, or different directions.

Chains and Belts

• Chain: Ideal for dusty

Classification of Non-Ferrous Metals

• Heavy: Copper, lead, tin, zinc, nickel, chromium, mercury, tungsten
• Light: Aluminum, titanium
• Ultralight: Magnesium

Copper

Minerals

• Cuprite, chalcopyrite, malachite, and native copper

Obtaining Process

• Wet Method: Electrolytic
• Dry Method: Grinding, separation, roasting, calcination, and reduction

Refinement

• Phase-phase thermal electrolytic

Features

• High electrical conductivity, ductility, and low resistance

Alloys

• Bronze, brass, and aluminum bronzes

Aluminum

Obtaining Process

• Bayer Method: Aluminum-electrolytic refinement

Characteristics

• Laminated, high affinity for oxygen, corrosion-resistant, weldable, and hard

Applications

• Industrial metals to form

Alloys

• Duralumin, aluminum-magnesium, aluminum-silicon, and Alnico

Lead

Obtaining

Material Classification

Natural Materials

These materials are obtained directly from nature, such as:

• Wood
• Coal
• Metal
• Stone

Artificial Materials

These materials are derived from natural materials through processing, such as:

• Glass
• Paper
• Cement

Synthetic Materials

These materials are created through chemical reactions involving artificial materials, such as:

• Plastics

Material Types and Their Properties

Ceramics

Ceramics exhibit the following properties:

• Fragility
• Low thermal conductivity
• Low electrical conductivity
• Hardness
• Brittleness

Metallic Materials

Metals possess these characteristics:

• High electrical and thermal conductivity
• Resistance
• Ductility
• Malleability
• Ability to form alloys with other elements to enhance properties

Plastics/Polyesters

Plastics and polyesters...

Unijunction Transistor (UJT)

A unijunction transistor (UJT) is a three-lead electronic semiconductor device with only one junction that acts exclusively as an electrically controlled switch. The UJT is not used as a linear amplifier. It is used in free-running oscillators, synchronized or triggered oscillators, and pulse generation circuits at low to moderate frequencies (hundreds of kilohertz). It is widely used in the triggering circuits for silicon controlled rectifiers. The low cost per unit, combined with its unique characteristic, have warranted its use in a wide variety of applications like oscillators, pulse generators, saw-tooth generators, triggering circuits, phase control, timing circuits, and voltage- or current-regulated supplies....

Wired Network Technologies

The wired network is mostly set up using an Ethernet cable. This can be done using three primary technologies:

Twisted Pair Wires

This technology was invented by Alexander Graham Bell. These wires are the oldest means of communication in computer networking. For more than 100 years, phone technology has used these wires. Most of us use these twisted wires in our homes and offices. They are the least expensive mode of communication used in networks.

In this setup, there is a pair of two copper wires, each 1-2 mm thick, twisted around each other in a spiral pattern. These are used to avoid interference from nearby similar pairs. There are a number of pairs bundled together in a cable by wrapping the pairs in a protective...

Aircraft Safety Regulations

1. Never smoke in the lavatories.
2. Never store your bag above your head in the overhead compartment during takeoff or landing.
3. Never listen to a radio on the plane without headphones.
4. Fasten your seat belt when the "Fasten Seat Belt" light is flashing.
5. Never inflate your life jacket inside the aircraft.
6. Always know the location of your nearest emergency exit.

Engine Cooling System Description

The water is stored in the radiator and the engine jacket. It's pumped along the bottom hose from the radiator to the engine jacket. It flows through the engine jacket and the heater radiator to the thermostat. When the thermostat is closed, the water keeps going round the engine circuit. When it is open, the water passes along the top...