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

Plastics

Plastics are materials formed by chains of carbon and hydrogen atoms. We call the chains polymers, while the atoms that form them are called monomers.

Thermoplastics

Thermoplastic materials are plastics that are softened by heating and can be formed and melted as many times as we want. This is because their polymers have weak bonds. (Polyethylene (PE), Polystyrene (PS), PVC (polyvinyl chloride))

Thermoset Plastics

The polymers of thermoset plastics criss-cross to form networks. Because of this bond, the plastics can be shaped using heat; however, once they have been formed, they cannot be re-melted to create different forms. (Melamine, Bakelite, Polyester resins)

Elastomers

Elastomers are very flexible materials that recover their shape and... Continue reading "Understanding Plastics: Types and Manufacturing Processes" »

Acceso Telnet

Switch(config)#line vty 0 15

Switch(config-line)#password cisco

Switch(config-line)#login Switch(config-line)#exit

Switch(config)#

Acceso remoto por SSH

Switch(config)#interface vlan 1

Switch(config-if)#ip address 192.168.20.1 255.255.255.0

Switch(config-if)#no shutdown

Switch(config)#hostname S1

S1(config)#ip domain-name cisco.com

S1(config)#crypto key generate rsa

The name for the keys will be: S1.cisco.com Choose the size of the key modulus in the range of 360 to 2048 for your General Purpose Keys. Choosing a key modulus greater than 512 may take a few minutes.

How many bits in the modulus [512]: 1024 % Generating 1024 bit RSA keys, keys will be non-exportable... [OK]

S1(config)# username usuario secret cisco *mar 1 1:13:48.23: %SSH-5-ENABLED:... Continue reading "Configuring and Securing Network Switches" »

Cloud Platforms

Cloud platforms enable outsourcing much of a company's IT department. This pushes knowledge workers out and often automates their work. Data analysis, customer information storage, and server maintenance can be moved to the cloud, providing the capitalist rationale for using these platforms.

Amazon Web Services (AWS) was developed internally to handle the company's increasingly complex logistics while building a massive logistical network.

Industrial Platforms

As data collection, storage, and analysis become cheaper, more companies bring platforms into traditional manufacturing. The most significant attempt is the 'industrial internet of things' or 'industrial internet'. As factories implement industrial internet components, a major... Continue reading "Platform Capitalism: Data as Raw Material" »

Ten Engineering Achievements:

• Telephone
• Computers
• AC and refrigeration
• Electronics
• Airplane
• Automobile
• Highways
• Spacecraft
• Internet
• Household appliances
• Imaging
• Radio and TV

Ten of Fourteen Challenges:

• Provide clean access to water
• Enhance VR
• Prevent nuclear terror
• Improve urban infrastructure
• Make solar energy economical
• Secure cyberspace
• Producing energy from fusion
• Manage the nitrogen cycle
• Engineer better medicine
• Advance health informatics

12 Steps:

1. Recognition of need
2. Problem identification and specification
3. Information gathering
4. Incubation and ideation
5. Development of concepts
6. Synthesis
7. Analysis
8. Prototyping and testing
9. Manufacturing
10. Marketing
11. Maintenance
12. Afterlife

Fundamental Differences Between Engine Lathe and Vertical Mill:

Lathe - the workpiece rotates but remains stationary,... Continue reading "Engineering Achievements, Challenges, and Key Concepts" »

Gear Mechanisms and Cogwheels Explained

Cogwheels are sets of wheels that have teeth, often called cogs. These teeth fit into the spaces between the teeth of another wheel, allowing one wheel to move the other. They transmit rotary motion between two connected axles, which can be parallel, perpendicular, or oblique. Gears can be cylindrical or conical, and all teeth must be the same shape and size. The two wheels and their corresponding axles rotate in opposite directions.

In this system, N1 and N2 represent the velocities of the corresponding wheels, while Z1 and Z2 are the numbers of teeth. The ratio Z1/Z2 is known as the gear ratio.

Uses:

• Industrial machinery
• Vehicles
• Domestic appliances (e.g., drills, food processors)

Worm Gear Systems: Function

... Continue reading "Mechanical Gear Systems: Types and Applications" »

Stone Materials in Construction

Stone materials are frequently used in construction due to their strength, durability, and resistance to weathering. Common applications include stone walls, cement pavements, and concrete pillars.

1.1 Extracting and Processing Stone

Stone is extracted from natural deposits. Some types, like marble and granite, exist as large blocks in quarries and require cutting into smaller pieces. Others, such as gravel and sand, are aggregates—fragments or grains of various sizes.

Stone Blocks

Certain stones, like granite and marble, are extracted in large blocks, which are then cut, shaped, and finished.

Quarrying

Large stone blocks are removed from the Earth's crust using methods like controlled explosions, mechanical drilling,... Continue reading "Stone Materials in Construction: Extraction, Processing & Applications" »

Construction and Engineering Terminology

Redesign (rediseño): Designing again in order to improve or change a design.

Regulations (Regulaciones): Laws and standards that a design must comply with, for example, safety regulations and quality standards.

Scale (Escala): The ratio between the size of items shown on a drawing and their actual size (in reality).

Schedule (horario): A list of planned activities or things to be done showing the times or dates when.

Set of (conjunto de): Collection/group.

Sketch (Boceto): A rough drawing of initial ideas, also used when production problems require engineers to amend design details and issue them to the workforce immediately.

Slab (Losa): The block of concrete that makes up a floor. It can be laid on the ground... Continue reading "Construction & Engineering Terminology: Definitions & Translations" »

... Continue reading "Understanding IoT: Components, Applications, and Future" »

Understanding Electricity and Electronics

Electricity

Matter is formed by atoms consisting of negatively charged particles (electrons) and positively charged particles (protons). Between these particles, there are forces of attraction or repulsion that generate a type of energy called electricity.

In a balanced atom, the number of protons is equal to the number of electrons. The forces of attraction and repulsion between these particles are balanced. When this balance is disturbed, the electrical forces become unbalanced and the electrons are driven by their electrical energy to other atoms in search of new balances.

We call this transfer of charges electrical current, and it is produced in conducting materials.

Conducting materials transmit electrical... Continue reading "Understanding Electricity and Electronics: DC and AC" »

Search Engine Functions: Crawling, Indexing, Publishing

Crawling

The process by which search engine robots (also known as spiders or web crawlers) discover new and updated web pages and add them to the search engine index. They achieve this by performing an algorithmic scan to determine which pages to crawl, then follow links to interconnect content across the web.

Indexing

Once a document or web page is located, it is processed and stored in a vast database, making it available for user retrieval. Search engines maintain large data centers where their robots process all the pages and information gathered during crawling.

Serving Search Results

The primary goal of search engines is to provide an almost immediate and relevant answer to the user's... Continue reading "Search Engine Mechanics: Crawling, Indexing, and Ranking" »