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

Understanding Sound Types

Analogue Sound Explained

Analogue sound imitates the vibrations of real sound. Its electrical signal has an analogue curve similar to a real sound wave.

Digital Sound Explained

Digital sound recording does not imitate vibrations but converts them into a binary code, the language computers use.

Digital sound is obtained through a converter. It transforms real sound (analogue) into a computer-readable format.

The Digitization Process

Role of the Converter

A converter is a device that transforms real sound into digital sound. The process is called sampling.

Sound Reproduction

To reproduce sound, the converter follows the inverse process, transforming the digital information back into real sound.

The MIDI System: Digital Communication

... Continue reading "Digital Audio Essentials: Sound, MIDI, and Formats" »

... Continue reading "Content" »

Investigative & Forensic Terminology

Forensic Kit A collection of tools used to discover scientific information about crimes.Fingerprint Powder A substance used to identify individuals by revealing the impression made on a surface by fingerprints.Slides Small pieces of photographic film projected onto a screen, often used for viewing evidence.Target To identify or concentrate on a specific person, object, or objective.Stakeouts Periods of surveillance conducted to gather evidence of criminal activity.Backup Support or help, often referring to additional personnel or resources.Lie Detector Test A test used to find out whether a person is telling the truth, typically involving a polygraph machine.Microfiche A small sheet of film on which... Continue reading "Essential Vocabulary for Investigations and Descriptions" »

Engine Operation & Control

1. Engine Start Procedure: For starting the engine, the H.P. cock should initially be closed.

19. Reheat and EPR: When reheat is used, Engine Pressure Ratio (EPR) remains constant.

22. Air Bleed and EGT: As air is bled off the engine, Exhaust Gas Temperature (EGT) will increase.

29. Reheat and Mass Gas Flow: When reheat is selected and in operation, the mass gas flow decreases.

38. Air Bleed and EGT (Repeat): As air is bled off the engine, Exhaust Gas Temperature (EGT) will increase.

Engine Components & Types

2. Clamshell Position: Clamshells are positioned 45º to the thrust line.

6. Anti-Icing Air Source: Air for anti-icing is taken from the H.P. compressor.

7. Centrifugal Compressor Impeller Types: The two types... Continue reading "Aircraft Turbine Engine Principles and Systems" »

Moulds for Casting

Mould made of ceramic material e.g. sand particles, bound together with a BINDER which may be:

• Clay: 90% sand, 8% clay, 2% water - green sand mould.
• Thermosetting resin system - coat sand with two or more reactants which cure to form a resin (typically 1 - 2 parts binder to 100 parts sand):
  • Curing begins immediately components are combined, for a period of time after initial mixing the sand is workable and flowable to allow filling of mould - No bake systems.
  • Phenolic - urethane no bake is most common.
  • Curing occurs upon application of heat – heat cured binder system.
  • Liquid thermosetting binder and a catalyst are mixed with dry sand. Upon heating the catalyst releases acid which induces a rapid cure in 10 – 15 s. Pattern is

... Continue reading "Types of Moulds and Their Characteristics for Casting" »

Network Security Essentials

Common Protocols and Ports

• TCP: Transmission Control Protocol
• SSH (TCP 22): Secure Shell
• Telnet (TCP 23): Insecure remote access
• HTTP (TCP 80): Hypertext Transfer Protocol
• HTTPS (TCP 443): Secure HTTP using SSL/TLS
• SSL/TLS: Encrypts web server communication with RSA and public/private key encryption
• FTP (TCP 21): File Transfer Protocol
• TFTP (UDP 69): Trivial File Transfer Protocol (no authentication or encryption)
• SNMP (UDP 161): Simple Network Management Protocol
• LDAP (TCP 389): Lightweight Directory Access Protocol
• NetBIOS (UDP 137/138): Network Basic Input/Output System
• Kerberos (UDP 88): Authentication protocol

Network Architecture

Internet → Router → Firewall → DMZ → Servers → Internal Network

• NAT/PAT: Network/Port

... Continue reading "Network Security & Incident Response: A Comprehensive Guide" »

Understanding Plastic Materials: Types and Applications

Thermoplastics: Properties and Common Uses

What are Thermoplastics?

Thermoplastics are composed of polymer chains that are weakly connected to each other. When thermoplastics are heated, they soften and can be molded into different shapes. Once they cool down, this process can be repeated as many times as needed, making them highly recyclable and versatile.

Key Types of Thermoplastics and Their Applications:

• Polyethylene Terephthalate (PET): Impermeable, transparent, and light.
  • Applications: Packaging for food, drinks, personal hygiene products, cosmetics, and cleaning products.
• High-Density Polyethylene (HDPE): Rigid and resistant.
  • Applications: Buckets, bottles, packaging for cleaning products,

... Continue reading "Plastic Materials: Properties, Types, and Applications" »

STONE MATERIALS: Stone materials are often used for construction because they are strong, durable and very resistant to weather conditions.

1.1. Extracting and processing stone: Stone is extracted from natural deposits. Some types exist as large blocks, such as marble and granite from quarries, which must be cut into smaller pieces. Other materials, such as gravel and sand, are aggregates.

1.2. Natural stone: -Limestone is a porous sedimentary rock. It is often used for sculptures and buildings, as well as for breakwaters in ports. -Limestone is used to produce lime and cement.

-Marble is a hard rock. Marble is cool to the touch and well-known for its resistance to compression and extreme weather conditions. Marble comes in a variety of colors... Continue reading "Stone Materials: Types, Properties, and Uses" »

This document provides answers to common questions about essential household systems, including electricity, water, heating, and smart home technology.

Electricity Distribution Board Components and Functions

What does an electricity distribution board contain? What functions do they have? Identify the different parts of a board in the photo (photo not provided).

Answer:

Components often include: EAO - Main switch, EO - RCCB, EAT - MCBs.

Functions:

• To protect people from accidental contact with electricity.
• To protect the system from excessive energy (overcurrents, short circuits).

Common Household Utilities

Name different household utilities.

Answer:

Electricity, gas, water supply, drainage, heating, and air conditioning.

When Does a Main Circuit Breaker

... Continue reading "Understanding Key Home Systems" »

Supercomputer

Supercomputers are the fastest type of computer available, used for complex calculations in specialized fields like weather forecasting. Their high cost limits their use to specific applications.

Mainframe

Mainframes were originally large cabinets housing central processing units. With the advent of smaller computers, the term evolved to describe powerful machines capable of handling large-scale operations and supporting numerous users simultaneously.

Minicomputer

Minicomputers are mid-sized systems that bridge the gap between mainframes and workstations. They can support multiple users and offer processing power suitable for various tasks.

Personal Computer (PC)

Personal computers are small, affordable computers designed for individual... Continue reading "Computer Types: From Supercomputers to Personal PCs" »