Notes, abstracts, papers, exams and problems of Technology

Understanding Alarm Systems

Types of Alarms

• Anti-Theft (Anti-Intrusion):
  • Housing
  • Establishments
• Security: Prisons, nuclear power plants, etc.
• Environmental: Fire, water leakage, gas, etc.
• Technical Alarms
• Medical Alarms
• Access Control Systems
• Monitoring in Industrial Processes

Objectives of Alarm Systems

• Familiarize users with the operation of various detectors.
• Describe the components of an alarm system.
• Enable installation and operational checks of alarm systems.

Anti-Intrusion Systems

• Passive System: Fences, security doors, etc.
• Active System: Detects threats using electronic controls.
• Deterrent System: Visible measures indicating robust protection.

Alarm System Components

A) Detector Elements

These send an electrical signal to the control unit by opening or... Continue reading "Understanding Alarm Systems: Types, Objectives, and Components" »

Electronic Display Technologies

1. Seven-Segment Display

Comprised of seven LEDs arranged to produce the idealized representation of a number. An optional eighth LED can serve as a decimal point. The number of management-control signals for each display is N = segments + DP. In multiplexed mode, the number of necessary control signals is N = segments + DP + viewers.

Variants

Alphanumeric seven-segment displays add extra segments to represent alphanumeric characters. These have largely been replaced by LED matrix displays.

2. LED Matrix Display

An array of LEDs that can generate characters, symbols, and pictures. The number of control signals required for each display is N = rows + columns.

3. Vacuum Fluorescent Display (VFD)

Composed of filaments,... Continue reading "Electronic Display Technologies: A Comprehensive Overview" »

External Combustion Engine

Steam Engine

The main elements of the steam engine and the functions they perform are:

• Hearth: This is an element external to the machine where burning occurs.
• Boiler: A vessel where steam is generated. A water pump driven by a boiler enters the liquid state at high pressure and a temperature close to ambient. In the boiler, the water heats and vaporizes. It goes on to a superheater where the temperature gets higher, but keeping the pressure of the boiler. Finally, the superheated steam enters the cylinder.
• Cylinder Engine: It consists of the distribution box, the slide, and the plunger. Inside the cylinder, the vapor expands and causes the piston reciprocation to be transmitted to the transforming elements of movement.

Active Directory provides a method to design a directory structure that meets the needs of any organization. It has many advantages, such as system scalability and ease in locating resources throughout a network.

• Active Directory allows a single point of management for all public resources, which may include files, peripheral devices, connections to databases, web access, users, services, etc.
• It uses the Internet DNS as the location service.
• Active Directory components are used to build a directory structure reflecting the needs of an organization.

Logical Structure

The logical structure of the organization is represented by domains, organizational units, trees, and forests.

• Domain: The central unit of the logical structure of Active Directory is

Metal Threading and Hole Machining

The screw is created through a metal removal operation.

Tools for Threading

Taps

Taps are cutting tools in the form of screws with longitudinal edges that allow for cutting. The main parts include:

• Active or entry: serves as the starting point.
• Guide or body: draws up the thread.
• Handle: the extreme end for handling.

Taps and Dies

Dies are employed for external threads. The interior carries a thread with 3 or more slots that form the cutting edge and allow for swarf removal. One face has a countersunk area (60 to 120 degrees) to facilitate thread initiation.

Giramachos and Portaterrajas

These are handles used for turning taps and dies, available in fixed or adjustable designs.

Technical Manual Threading: Steps

1. Draw the

Types of Dimensions

Dimension Series

Dimension series are easy to implement but can accumulate errors during manufacturing. They are suitable for conventional parts that don't require special machining, such as numerical control machining. This method involves a series of operations in the manufacturing process.

Parallel Dimension

In this system, all dimensions are oriented in the same direction. It's used when a reliable reference is needed, as it avoids accumulating manufacturing errors since all measurements originate from the same point.

Combined Dimension

Combined dimensioning merges serial and parallel dimensioning. While it simplifies dimension lines and maintains necessary measurements, it requires adding or subtracting measurements.

Progressive

Rotor Certificate: Key Inspection Points

1. Shaft and Polar Icecaps: Carefully inspect the shaft and polar icecaps for any cracks or signs of oxidation.
2. Shaft Pads: The shaft pads on the bearings should exhibit a smooth surface and no signs of excessive wear on the slip rings.
3. Slip Ring Cleaning: Clean the slip rings with a cloth soaked in alcohol. They should appear smooth and shiny. If sparking, roughness, or excessive wear is observed, the slip rings should be inspected using a lathe.
4. Induction Coil Resistance:
   • Using an ohmmeter, measure the resistance of the induction coil.
   • Apply the probes to the slip rings. The reading should match the manufacturer's recommended value (typically 4 to 5 ohms as a guideline).
   • Measure the insulation of the induction

Belt Drives

Belt Drive Basics

A belt drive transmits rotational motion between two shafts using a flexible belt. The belt engages with pulleys on each shaft, allowing for power transmission. Belts must be flexible to handle initial tension and generate sufficient friction to prevent slippage.

Toothed Belt Drives

Toothed belt drives are efficient and used in various machines. They combine the advantages of flat belts, V-belts, chains, and gears while minimizing their drawbacks. These drives require no lubrication or maintenance. Toothed belts typically consist of fiberglass, neoprene, and a nylon coating.

Cable Drives

Steel Wire Rope (SWR) Drives

SWR drives use an endless steel cable wound between two pulleys, sometimes with intermediate supports.... Continue reading "Understanding Belt and Chain Drives" »

Effort

An effort (q) is the internal tension experienced by bodies subjected to an action or several forces.

• Traction: The forces trying to stretch the body over which they apply.
• Compression: The forces trying to crush or compress a body are opposite and act inside the body.
• Flexion: The forces trying to bend the element on which they are applied.
• Torsion: The forces trying to wring the item on which they act.
• Shear: The forces act like two blades of scissors.
• Buckling: It is a composite effort with compression and flexion.

Mechanisms

These are intended to transmit or transform forces and movements from a driving element to another element.

• Mechanisms of transmission of motion: Pass on to another point the motion produced by a driving element.
• Motion

Memory Components

For a device to function, it requires:

• Storage Medium/Support: The physical element containing the memory, capable of supporting two different energy states. The medium can be:
  • Discrete: A single item stores each bit.
  • Continuous: Bits are stored sequentially, differentiated by a clock signal.
• Memory can be classified based on data retention:
  • Durable/Non-Volatile: Information is stored permanently unless intentionally erased.
  • Volatile: Information is lost when power is removed.
  • Refresh-based: Information fades over time and requires periodic rewriting.
  • Destructive Read: Reading erases the data, requiring a re-write after each read operation.
  • Read-Only: Information can only be recorded once.
• Drivers: Manage reading and writing operations.