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

Heavy Work

This term refers to the part of a building's construction that includes the foundation, structural framework, walls, and roof girders.

Joist

A smaller beam, sometimes supported by principal beams or girders. In the context of poplar wood, this name also refers to the first piece carved with an axe from the tip of the trunk, typically 5 feet long.

Cuarton

This term indicates a piece obtained by sawing a whole tree crosswise. Generally, this name is given to sawn pieces with a thickness and width ranging from 2 to 6 inches.

Crowbar / Prop

This term can refer to:

• Vertical uprights or props used to support the formwork for concrete slabs and beams. Shims are often placed at their base to adjust the height.
• A sturdy lever or bar used for prying

Industrial Processes and Materials

Item 1: Production Cycle and Industry Types

1. The Production Cycle:

Industries can be classified into:

• Extractive Industries
• Processing Industries

2. Extraction of Raw Materials:

According to the type of resource:

• Mineral energetics
• Non-metallic rocks and minerals
• Hydrocarbons
• Plant and animal materials

3. Processing Industries:

• Steel and metal
• Petrochemicals
• Paper and artificial wood industries
• Textiles and leather
• Industrial ceramics, glass, and building materials

4. Automobile Manufacturing Process:

1. Realization of parts by melting and molding.
2. Union of parts by welding, adhesives, or threaded elements.
3. Realization of finishing by coating with paints, enamels, and varnishes.
4. Control, product warehousing, and packaging.

5. Saving

Camera Types for Video and Television

The camera's function is to capture the image. We can find a wide variety of video and television cameras, from cheaper designs to more sophisticated markets. We can find a great variety of models. When choosing a camera, several factors must be considered: price, practical aspects (e.g., weight), operational characteristics, and performance (image quality).

Studio Cameras

Studio cameras, for example, are used on set and are usually connected to a production control room. They create high-quality images. They tend to be large, bulky, heavy, expensive, and difficult to transport. They usually incorporate a prompter.

EFP Cameras

EFP stands for Electronic Field Production. These are lightweight cameras. Normally,... Continue reading "Camera Types and Supports for Video Production" »

**Plastic Materials: Properties, Types, and Manufacturing**

**Properties of Plastics**

Definition: Plastics are materials of organic origin, solid at room temperature, and easily molded by applying heat. They have a high molecular weight.

Most used: Polypropylene (PP)

Qualities:

• Weight reduction
• Noise damping
• Impact absorption
• Chemical resistance
• Corrosion resistance
• Thermal and acoustic insulation

Disadvantages:

• Low mechanical resistance
• Cannot withstand high temperatures
• Easily scratched
• Can easily capture moisture
• Sensitivity to sunlight
• Sensitivity to environmental conditions

**Chemical Processes**

Plastics are of organic origin and are chemical compounds formed by the union of several units. They can be formed by polymerization, polycondensation, or polyaddition.... Continue reading "Plastic Materials: Properties, Types, and Manufacturing Processes" »

Autoclave: Moist Heat Sterilization

Autoclave sterilization utilizes moist heat to effectively destroy spores, fungi, bacteria, and viruses. This process requires temperatures above 120°C. The autoclave chamber features a thick, stainless steel wall and a sealing lid. It includes a pressure gauge to monitor temperature and pressure, and a safety valve that activates when pressure reaches a dangerous level. A key controls the steam vent, enabling cooling. The tank contains water up to a specific level and a grid for placing objects. Heating can be electric or gas-powered.

Sterilization Phases in the Autoclave Process

Conditioning

Objects are placed on the grid, the lid is closed, and the vent key is opened.

Exposure to Vapor

The vent key is closed,... Continue reading "Autoclave and Ethylene Oxide Sterilization Methods" »

LDR (Light Dependent Resistor): These are resistors whose resistance value changes when illuminated by light (visible or invisible, such as ultraviolet or infrared).

LDR Features:

1. Its resistance value depends on the amount of light that strikes it.
2. Ohm's Law does not apply directly.
3. Typically made from cadmium sulfide. This material, when kept in the dark, has very few free electrons, resulting in high resistance. However, when illuminated, it releases electrons, decreasing the resistance. This makes it a photoconductor.
4. Manufacturers provide values such as resistance in total darkness (R), resistance under illumination (e.g., 1000 lux), permissible maximum stress, and maximum power.
5. Can be used in lighting systems as detectors.

NTC (Negative Temperature

Railway Track Crossings: Name, Schema Usage, and Design

Crossings are essential devices that ensure the continuity of connections via different paths and can provide maximum security. They consist of combinations of two devices:

• Bypass: Allows the separation of a railroad into two or more tracks.
• Journey: Allows the intersection of two roads.

Components of Diversions and Crossings

Diversions and crossings are formed from three elements:

• Change: The contra-needle assembly. The needle is the mobile part, and the immobile part is the contra-needle. The end of the needle tip, which is not machined, connects to the union rails and is called the heel. The contra-needle is a normal lane. The needle has to transition from one lane to become normal to an

Common PC Power Problems

Some of the most common power problems and their descriptions:

• High Voltage Fluctuations: Unexpected spikes in voltage.
• Power Outages: A total loss of electrical power.
• Overvoltage: An increase in voltage beyond the normal level. This can occur when a high-energy device is suddenly switched off.
• Voltage Drop: The opposite of overvoltage; a gradual decrease in voltage, potentially leading to a power outage.

Symptoms of Power Supply Issues

Some symptoms that may indicate a power supply problem include:

• Unexpected Freezing: The PC freezes for no apparent reason.
• Data Errors: Write errors or errors accessing files occur.
• Component Failures: Internal components fail, their intensity varies, or the PC behaves strangely when connecting

Questions and Answers About Materials

1. What Kinds of Natural Fiber Fabrics Are There?

• a) Plant and animal fibers, including those of seaweeds.
• b) Plant and animal fibers.
• c) Plant, animal, and mineral fibers.
• d) Animal and seaweed fibers.

2. What Fibers Are Manufactured Without the Use of Any Natural Product?

• a) All use natural products.
• b) Synthetic.
• c) Artificial.
• d) Both b and c.

3. What Characteristic Should a Fabric Have If It Will Be in Contact With Skin for Many Hours?

• a) Tensile strength.
• b) Hygroscopy.
• c) Resistance to chemicals.
• d) Soft to the touch.

4. The Origin of Plastic Can Be:

• a) Natural and artificial.
• b) Natural, artificial, and synthetic.
• c) Elementary, artificial, and natural.
• d) Natural and recycled.

5. The Degree of Polymerization Is:

• a)

Understanding Cryptography: Key Concepts

Confidentiality: Prevents the disclosure of information.

Authentication: The act of establishing or confirming that something or someone is authentic.

Integrity: Prevents the modification or destruction of unauthorized information. Passive threat.

Symmetric vs. Asymmetric Keys

Symmetric Key: In symmetric key systems, the same key is used to encrypt and decrypt.

Asymmetric Key: In asymmetric key systems, encryption uses one key, and decryption uses a complementary key.

Cryptography Explained

Cryptography is the art of writing messages with a secret key or in an enigmatic way. It's a branch of mathematics, informatics, and telematics that uses mathematical methods and techniques to encrypt messages or files through... Continue reading "Understanding Cryptography: Confidentiality, Integrity, and Authentication" »