Notes, summaries, assignments, exams, and exercises for Technology for Secondary education

Thermoplastics

• Polystyrene (PS): Obtained from benzene; resists impact. (Drawing tools, automobile interiors)
• Polyvinyl Chloride (PVC): Obtained from acetylene and hydrochloric acid; offers mechanical resistance and hardness. (Pipes, cabinets, windows)
• Polymethyl Methacrylate (PMMA): Transparent and impact-resistant. (Decorative items, goggles)
• Polycarbonate (PC): Derived from carbonic acid; features transparent gloss. (Police badges, CDs)
• Polyamide (PA): High strength, stiffness, and good toughness at high temperatures. (Toothbrushes, racket strings)

Thermosets

• Phenolic Resin (PF): A hard, dark, and fragile plastic obtained from phenol and formaldehyde. (Telephones, kitchen utensil handles)
• Polyester Resin (UP): Obtained from coal tar and styrene;

Oil Tank Functions and Design

The oil tank, or reservoir, serves several critical functions in a hydraulic system.

Key Objectives of an Oil Tank

• Store System Fluid: To provide an adequate supply of hydraulic fluid for the system.
• Contaminant Settlement: To allow contaminants in suspension to settle out of the fluid.
• Temperature Regulation: To help maintain the fluid temperature within desired limits by dissipating heat.
• Air Dissipation: To facilitate the release of dissolved air or foam from the fluid.

Baffle Positioning in Oil Tanks

The position of baffles inside the tank is very important. Firstly, they establish separation between the suction line and the return line, preventing aerated or contaminated return oil from being immediately drawn back...

Common Cyberattacks and Threats

• Cyberattack: An attempt to damage or gain unauthorized access to systems — intento de dañar o acceder sin permiso
• Phishing: Fraudulent messages used to steal user credentials — mensajes falsos para robar datos
• Malware: Malicious software designed to harm systems — software que daña sistemas
• Ransomware: Malware that encrypts data and demands payment — programa que cifra datos y pide dinero

Advanced Attacker Techniques

• Lateral movement: Moving through a network to access other systems — moverse por la red para acceder a otros equipos
• Credential theft / harvesting: Stealing usernames and passwords — robo de usuarios y contraseñas
• Unauthorized access: Entering a system without permission — acceso sin permiso
• Social

Poodle Instantiation Example

B. The Poodle variable myDog is instantiated as a Poodle. The instance variable size is initialized to "toy". An implicit call to the no-argument Dog constructor is made, initializing the instance variable name to "NoName".

Book Instantiation Example

C. Object myBook is created using the one-argument Book constructor, which uses super to set myBook's title attribute to "Adventure Story". Object yourBook is created using super to call the Publication no-argument constructor to set yourBook's title attribute to "Generic".

Tree Instantiation Example

B. Object tree1 is created using the DeciduousTree constructor, which uses super to set tree1's treeVariety attribute to "Oak". Object tree2 is created using the EvergreenTree...

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

Understanding Platform Capitalism by Nick Srnicek

This article examines Platform Capitalism by Nick Srnicek. This global business model defines the modern age of social media, big data analytics, and tech-centered venture capital investment. Major platform operators—including Google, Amazon, Facebook, Microsoft, and Apple—are now competing for business in sectors like education, where technology investment has boomed due to increased startup funding.

Defining the Digital Platform

The concept of the “platform” in platform capitalism is complex. Broadly, a platform refers to internet-based applications, such as social media sites, that process information, channel social traffic, and enable the creation and sharing of user-generated content....

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

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,...

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

Understanding Malware Threats

Malware encompasses any program, document, or message that can harm your computer. This harm can include deleting data, slowing down performance, or causing programs to malfunction.

Types of Malware

Viruses

A virus is a program that installs itself on your computer without your knowledge. Its primary purpose is to spread to other computers and execute malicious actions.

• Objectives: Affect the integrity and availability of data and software.
• Affected Elements: Data and software.
• Solution: Antivirus software (scanning, file checking, and resident protection). Prevention, detection, and recovery are key.

Trojans

Trojans are small applications disguised as utility programs, images, or messages. Their purpose is to create a...