Notes, abstracts, papers, exams and problems of Technology

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

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

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" »

Tough:we can manufacture Windows, bottles or Lenses for impact resistant glasses.Littles Resistant to strain:we cannot build structures (bridges, buildings…) with plastic, not object (ladders, bicycles…) that must resisit great strains.Phoodegradable: continued exposure to Sunligth degrades them and makes them more brittle over time.

MÉTODOS:

Compression:applies mainly to termostable plastics.Plastic Is placed in a Steel mold and it is heated to make it pasty.Pressure is applied With a hydraulic press so that the plastic takes the shape of the mold(lamp Holders).Vacunn forming: a plastic Sheet is placed on the mold of the object we want to manufacture.Using electric Resistances the sheet is heated untilit softens. The mold and the hot sheet

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" »

What is Cloud Computing?

Cloud computing is the delivery of computing services over the internet to offer faster innovation, flexible resources, and economies of scale.

Top Benefits of Cloud Computing

• Cost: Eliminates the capital expense of buying hardware and software and setting up and running on-site data centers.
• Speed: Most cloud computing services are provided self-service and on-demand, so even huge amounts of computing resources can be provisioned in minutes.
• Global Scale: Offers the ability to scale elastically.
• Productivity: Cloud computing removes the need for many tasks, so IT teams can spend time achieving more important business goals.
• Performance: Reduces network latency for applications and provides greater economies of scale.
• Security:

1. Non-Volatile Memory

Non-volatile memory retains stored information even when not powered. It is used for secondary storage or long-term persistent storage. Examples include:

• CD
• Hard Disk (similar reading and writing time)
• Solid-State Drive (SSD): No moving mechanical components, no difference for sequential vs. random reading, but a significant difference between reading and writing.
• ROM
• Flash Memory
• Magnetic Tape: Natural sequential reading and writing, suitable for backups.

2. File System

A file is a contiguous logical address space that can be written to, read from, opened, closed, and deleted. It has the following attributes:

• Name
• Unique ID
• Type
• Location
• Size
• Protection
• Date

Information about files is stored in file system structures.

3. Directory

A directory... Continue reading "File Systems: Structure, Management, and Optimization" »

Technology: Creating Practical Solutions

Technology is creating practical solutions to satisfy human needs and problems.

Factors in the Technological Process

Physical and scientific concepts

Technical drawing

Materials and their properties

Work techniques

Economic factors

Information technology

Stages of the Technological Process

Needs and problems

Collecting information

Designing (drawing)

Planning (materials-tools-time-money-people in charge)

Building

Evaluating and checking

Writing a report

Materials for technical use

Solid Bulk Terminals

As the name implies, solid bulk terminals handle bulk cargo and are typically located near port entrances.

Design

These terminals don't require a continuous berth. The current trend is to construct them with a light working platform.

Goods

Solid bulk terminals handle various goods, categorized as follows:

• Primary Bulk Cargo: Iron ore, cereals, coal, bauxite, and phosphates.
• Secondary Bulk Cargo: Metals, minerals for construction (coke, cast iron, cement, magnesium ore, scrap), and other agricultural products.

Storage

Storage methods depend on the cargo type:

• Clean Bulk: Products for human or animal consumption (cereals, flour, animal feed) require specific handling and storage facilities.
• Dirty Bulk: Materials from mining and steel