Notes, abstracts, papers, exams and problems of Technology

Plastic Extrusion and Molding Processes

Extrusion profiles are used to create long, uniform sections. This process utilizes a specialized machine called an extruder, which operates similarly to a kitchen cutting machine. Plastic granules are poured into a feed hopper and flow into a chamber where a screw rotates. The extruder heats the plastic to between 150 and 250 degrees Celsius to soften it and force it through a die, creating the desired shape.

Extrusion and Blow Molding

Extrusion and blow molding are used for creating items like electrical lighting components, bottles, and toys. A hollow preform, called a parison, is extruded and then placed into a mold. Air pressure is then injected to expand the plastic, conforming it to the mold's shape.... Continue reading "Plastic Extrusion and Molding Processes: A Comprehensive Look" »

Hot Water System Essentials

1. Tube Layout Characteristics: Pre-Use Checks

• Measuring diameter and wall thickness
• Analyzing galvanized steel tubing
• Testing hot water flow capacity (if applicable)
• Checking width
• Identifying accessory types

2. Tube Layout: Records Before Covering

• Ensuring no water leaks from joints under load tests
• Positioning hot water lines above cold water lines
• Maintaining minimum distances from other utilities:
  • 3 cm from gas pipes
  • 4 cm from other pipes
  • 30 cm from electrical lines

3. Types of Pipe Connections

• Concrete (with metal jacket): Double-shirt welding bead (interior and exterior)
• Steel: Thread, flange, or welding
• Cast Iron: Flange connection, automatic and mechanical joint gasket
• Polyvinyl Chloride (PVC): Screw joints, gluing, or ring

Water and Sewage

• Greywater: Waters that have been used in toilets, etc.
• Sewage: Waters that have been used to remove excrement.
• Downpipe: A conduit that carries wastewater to sewers.
• Distribution Network: Deals with the distribution of water ready to drink, called potable water.
• Siphon Outlet: U-shaped tube that always contains water to prevent the passage of odors.

Environmental Design

• Environmental Design: Aims to achieve thermal comfort inside a house naturally, taking into account the environmental conditions of the house and climate.

Broadband and Digital TV

• Broadband: A communication connection that allows faster data flow between sender and receiver.
• Decoder: A device that receives a signal and interprets it by offering a sound and signal that

IPL (Initial Program Load)

IPL (Initial Program Load) -> Power On Self Test (POST)

BIOS (Basic Input/Output System)

BIOS: A set of input and output routines. It handles the communication between the operating system and hardware.

Types of Memory

• RAM (Random Access Memory): For both reading and writing.
• ROM (Read-Only Memory): For reading only.

Types of ROMs

• ROM: Read-Only Memory.
• PROM: Programmable Read-Only Memory. A digital memory where each bit's value depends on a fuse that can be burned only once.
• EPROM: Erasable Programmable Read-Only Memory. Read sequentially. Less reading provides a greater margin for error.
• EEPROM: Electrically Erasable Programmable Read-Only Memory. The signal is updated and erased with the BIOS.

RAM and ROM Classification

• Dynamic

Shipboard Equipment and Parts

Anchors

Anchor: An iron instrument, heavy and strong, shaped like a harpoon or hook. Doubled and attached to a rope, chain, or cable, it's thrown into the water to hold a vessel.

1. Plow anchor (Figure 1-37)
2. Danforth anchor (Figure 1-35)

Windlass

Windlass: A horizontal axis machine used to weigh chains. It has an iron mechanism called a chainstopper to bite and stop the chain. Often incorporates drums (Cabirol or warping ends).

Gypsy

Gypsy: A drum-shaped part of the windlass with notches or molds where the chain's mating link engages as the anchor is raised or lowered. The gypsy is in gear when turning the reel to raise the anchor, or it decouples and engages the brake to stop the shaft's rotation.

Escobar

Escobar: The location... Continue reading "Essential Shipboard Equipment and Terminology" »

Item 4: Characteristics of the Internal Combustion Engine

1. Engine Performance

Chemical Energy (Fuel) / Thermal Energy (Combustion) / Mechanical Energy (Piston Displacement)

The chemical energy contained in the fuel is converted into heat through combustion. The resulting increase in pressure moves the piston, thus obtaining mechanical energy. Efficiency is calculated as follows:

n = (Energy obtained / Energy supplied) * 100 (%)

Power Loss:

• Heat Loss: Due to the cooling system and heat transfer to the outside.
• Mechanical Losses: Friction between moving parts and driving auxiliary devices.
• Chemical Losses: Due to incomplete combustion.

2. Types of Performance

• Thermal
• Mechanical
• Effective
• Volumetric

3. Key Features of Engines

• Engine Torque
• Specific Power
• Specific

Food Market Regulations

Conditions for Food Markets

1. The flooring must be non-slip and waterproof, with adequate drainage to facilitate evacuation.
2. Walls and pillars must be covered with waterproof, smooth, and easily cleanable materials.
3. Adequate natural or mechanical lighting must be provided.
4. Running water (hot and cold), sinks, and sufficient waste disposal capacity are required.
5. Measures must be in place to prevent the entry of insects, spiders, and rodents.
6. Loading and unloading should occur through separate access points.
7. Enclosed areas are required for the exclusive use of packaging waste, with immediate access to the public highway.
8. Bathrooms with toilets, separated by gender and distinct from public areas, are necessary. Mechanical ventilation

Steel

Iron in its pure state lacks the strength and toughness for common applications. However, combining it with small amounts of carbon creates steel, a metal with properties varying according to its carbon content and other alloying elements like manganese, chromium, silicon, and aluminum.

Steel: Chemical Composition

Steel primarily consists of iron and carbon. It also contains trace elements, including sulfur and phosphorus, which are difficult to remove but are reduced to harmless proportions (<0.05%). Easier-to-obtain elements like silicon and manganese (0.2-0.9%) prevent oxidation of the molten metal. The remaining 97.5-99.5% is iron. Steels with this composition are called carbon steels. Their carbon content determines their classification,... Continue reading "Steel Composition, Properties, Manufacturing, and Classification" »

Hagia Sophia: A Byzantine Masterpiece

Hagia Sophia stands as the masterpiece of Byzantine art. It was conceived not merely as a basilica for the people, but as the great church of Emperor Justinian.

Designers and Influences

Its principal architects were Anthemius of Tralles and Isidore of Miletus. Isidore the Younger, nephew of Isidore of Miletus, also contributed later. The work as a whole significantly reflects the building traditions and technological advancements of Roman architecture.

Innovative Architectural Plan

On the ground level, the plan ingeniously synthesizes a basilica with three naves (a Western tradition) and the centralized plan characteristic of Eastern tradition. It establishes a three-nave layout embedded within a Greek cross

Coaxial Cable Specifications

A coaxial cable features a copper connector at its center, covered by an insulating layer, then a layer of armor, and finally an outer coating layer. It uses BNC connectors (type and tipoF). Coaxial cables are not very flexible, support speeds of 10 Mbps, and require a connection to ground.

Uses and Applications of Copper Wires

• Coaxial Cable: Used in radio frequencies modulated as cable TV.
• Twisted Pair: Used for data transmissions and VoIP.

Fiber Optic Cable Elements

• Core: The element that transmits light, located at the center of the fiber optic cable (FOR). The core is made of silica or glass.
• Cladding: Covers the core.
• Buffer: Helps protect the core and cladding from damage.
• Resistant Material: Prevents the buffer surrounding