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

Natural Materials

Plant-Based Materials

• Paper

  Paper consists of sheets of cellulose fiber. It is a dense, soft material primarily used for books and is currently recycled.

• Wood

  Wood is a composite of cellulose and lignin, obtained from tree trunks. It is lightweight and quite resistant. While a renewable resource and recyclable into paper, excessive logging prevents forest renewal, leading to deforestation. Wood is widely used in manufacturing furniture, doors, siding, and for walls and floors.

• Textile Fibers

  • Cotton

    The most important textile fiber, cotton is obtained from filaments within the seed capsules of the cotton plant. It produces lightweight, durable, and breathable fabrics suitable for warm climates.

  • Linen

    Obtained from flax stem strands,

Hydraulic Pumps: Boosting Suction and Discharge

• Constant High-Pressure Flow: A moving part (piston) is housed inside a casing.
• External-Tooth Gear Pump: Reverse rotation occurs at the entrance. There is a negative pressure difference that allows the transfer of the deposit to the inlet of the pump.
• Internal-Tooth Gear Pump: Features external teeth on the driving gear and internal teeth on the driven gear, along with a crescent-shaped plate.
• Lobe Pump: Similar to an external-tooth gear pump but designed for constant flow (unbalanced).
• Unbalanced Vane Pump: The rotor rotates within the volumetric ring and is located eccentrically.
• Balanced Vane Pump: The rotor and the ring are concentrically arranged, creating two zones of aspiration and discharge.

Resistors: Limiting Current Flow

Resistors are fundamental electronic components that limit and regulate the amount of current flowing through a given circuit. They protect other components by ensuring that a very high current does not circulate through them.

Types of Resistors

Fixed Resistors & Tolerance

Fixed resistors have a constant resistance value. Their tolerance indicates the maximum deviation from their stated value, expressed as a percentage. This value is typically indicated by the first three bands or digits on the component.

Variable Resistors: Potentiometers

Potentiometers are variable resistors commonly used in electronic circuits to create adjustable voltage drops or to control current. Their resistance can be manually changed.... Continue reading "Fundamental Electronic Components Explained" »

Flat Screen Electroluminescent Display

This is a type of flat-screen display based on the electroluminescent effect. This effect involves the non-thermal conversion of electric energy into light. Light is generated by striking a phosphorescent material with high-energy electrons.

Benefits:

• Excellent viewing angle
• Excellent brightness
• Quick response

Disadvantages:

• Low contrast
• Monochromatic
• High cost
• High power consumption

Flat Plasma TV

In flat plasma TVs, light is emitted by a phosphor excited by a plasma discharge of noble gas. This technology involves applying a high voltage between two electrodes, generating a gas discharge. After colliding with a phosphorescent material, light is emitted. The term "plasma" refers to the ionized gas during discharge.... Continue reading "Flat Screen Display Technologies: Plasma, Electroluminescent, and Touchscreen" »

Concurrency Issues in Process Execution

Understanding Concurrency Problems

Concurrency issues arise when multiple processes or threads execute simultaneously and access shared resources. These issues can lead to incorrect results or system instability if not managed properly.

• Mutual Exclusion

  Mutual exclusion ensures that when one process enters its critical section (the part of the code that accesses shared resources), it must complete its execution within that section before any other process can enter its own critical section for the same shared resource. This mechanism is crucial for preventing data corruption and maintaining data integrity.

• Deadlock

  Deadlock occurs when two or more processes are running and each requires a resource that is currently

Plastic Properties

Lightweight: Due to their low density, plastics float and overcome most water resistance.

Insulating Capacity: Plastics offer excellent thermal and electrical insulation, making them ideal for plates and electrical conductivity applications.

Chemical Resistance: Plastics can withstand various environmental conditions without alteration.

Versatility: The properties of plastics can be modified, offering a wide range of possibilities.

Manufacturing Ease: Plastics are easy to model and can adopt various shapes.

Sustainable Practices and Environmental Impact

Reduce: Purchase or consume products only when strictly necessary.

Reuse: Give products new life by offering them new possibilities for use.

Recycle: Transform unusable objects into... Continue reading "Plastic Properties and Manufacturing Techniques" »

Network Infrastructure Cables

2 Power Cords (Mains)

These stem from the main network cables and connect to distribution poles, manholes, or building facades. These cables are distributed through adequate piping. They run via interspersed small underground pipes and accessible local street access points called chambers. This set of power cables is called the mains.

3 Distribution Cables

This is the network of branches feeding through lateral paths using lower capacity cables. This set is called the distribution network. These network cables, in turn, divide and end at interconnection points, from which the various subscriber lines originate.

These interconnection points are of two types:

• If they are outdoors and contain a small number of pairs, they

CAV Rotary Injection Pump Fundamentals

In CAV rotary injection pumps, fuel is sent from the transfer pump to the hydraulic head at a pressure regulated by a valve. The metering valve precisely controls the fuel flow, which is governed by the throttle position and the speed regulator assembly. The distributor then raises the fuel pressure from the transfer level to the injection pressure, distributing it to the various nozzles.

Fuel Pressure Transfer Mechanism

Under normal operating conditions, the generated pressure causes the control piston to move to the right, against the action of its spring. This pressure is applied to the valve through a conduit from the transfer pump. When the pressure exceeds the limits set by the adjusting screw, regulation

Electronics and Electricity

Electronics is the science and technology concerned with the study of electrons and their applications in information processing and transmission.

Direct Current (DC)

Direct current (DC) is the flow of electrons in a single, constant direction with consistent voltage and current over time.

Alternating Current (AC)

Alternating current (AC) is a variable current where voltage and current continuously change direction. The most common type of AC used in homes is sinusoidal, meaning it's a periodic electrical signal that repeats at regular intervals.

Transformers

Transformers are used to increase voltage for electricity transmission from power plants and then decrease it for safe household consumption.

Key AC Parameters

• Cycle:

Issue 31: Fuel Injection Power Systems

Food for Fuel Injection

This system supplies power to the combustion engine, replacing the carburetor with a system that injects gasoline directly into the air intake. Advantages of fuel injection systems:

• High performance
• Less fuel consumption
• Fast adaptation
• Reduced pollutants

Injection can be direct or indirect. Direct injection sprays fuel directly into the cylinder, maximizing engine power but requiring higher pressure. Indirect injection sprays gasoline into the intake manifold, with a simpler installation due to lower pressure requirements. Injection can also be continuous or discontinuous.

Mechanical Fuel Injection

Mechanical injection systems are powered by the internal combustion engine or lack an actuator.... Continue reading "Fuel Injection Power Systems: Operation and Types" »