Notes, abstracts, papers, exams and problems of Technology

Q1. Synchronous

1. Asynchronous
2. Isochronous
3. None of the above

Q2. Full Duplex

1. Half Duplex
2. Simplex
3. All of the above

Q3. Modulation

1. De-modulation
2. Multiplexing
3. De-multiplexing

Q4. TDM

1. WDM
2. CDM
3. All of the above

Q5. FDM

1. TDM
2. WDM
3. CDM

Q6. Electrical

1. Light
2. Electromagnetic
3. All of the above

Q7. Less Susceptible

1. More Susceptible
2. Not Susceptible
3. None of the above

Q8. Fiber Optic

1. Twisted Pair Cable
2. Coaxial Cable
3. Both B & C

Q9. Reflected

1. Refracted
2. Travelling along the boundary
3. None of the above

Q10. Digital

1. Analogue
2. Both A & B
3. None of the above

Q11. Phase and in Amplitude

1. Phase and Frequency
2. Amplitude and Frequency
3. All of the above

Q12. Increased Unused Slots

1. Decrease the Unused Slots (Maybe)
2. Eliminating Unused Slots
3. Do Not Deal with Unused Slots

Q13. Mathematical Formula

1. Analogue Signal
2. Digital Signal
3. Any

Transformers

Alternating current can be increased or decreased by a transformer. This allows us to transfer electrical energy at very high voltages and over hundreds of kilometers, without losing any of the energy as heat. Transformers consist of two windings made of copper wire. If we apply an alternating current to one of them, it will produce a certain voltage in the other.

Electromagnetic Effects

He noticed that electricity could be generated by using a magnet and an electrical conductor. This principle allows us to build dynamos and alternators.

Effects of Electric Current: Heat

The movement of electrons through an electrical cable is both slow and disorderly. The electrons often collide, increasing the temperature of the cable itself.

Light

For... Continue reading "Understanding Transformers, Electromagnetic Effects, and Electrical Current" »

Industrial Transformations

Wood

Pith: the middle part of the trunk

Heartwood: hardest and darkest, best part for woodwork

Sapwood: recent growth used for more artistic woodwork

Bark: exterior layer, protects the plant from outside attacks

Cambium: thin transparent layer of live cells

Hardwood

Beech: used in furniture and floors because it bends and is easily shaped

Oak: used in parquet floors, boats, etc.

Mahogany: used in joinery, musical instruments, etc.

Softwood

Pine: used in electrical posts, boats, etc.

Silver fir: used in building, carpentry, etc.

White poplar: used in frames, paper, etc.

Engineered Wood

Plywood: formed by gluing together thin sheets with synthetic resins

Chipboard: made with wood shavings and chips which are glued together

Fibreboard: fibers come from grinding

Carpentry

Scanning Tunneling Microscopy (STM) and Atomic Force Microscopy (AFM)

Scanning Tunneling Microscopy (STM)

Scanning Tunneling Microscopy (STM) is an instrument used for imaging surfaces at the atomic level, revealing the topography of conductive specimens. It measures tunneling current and can be used in air, water, and various gas environments, at temperatures ranging from near zero Kelvin to a few hundred degrees Celsius. STM operates in two modes: constant interaction mode and constant height mode.

Advantages of STM

• High resolution, not limited by diffraction
• Small sample size
• Can modify samples to create small structures
• Does not require a partial vacuum

Disadvantages of STM

• Difficult to determine detailed shapes
• Slow scanning speed
• Small image sizes
• Not

A file is a set of ordered documents that are related by some circumstance or event. It is essential for a company to have a file, that is to sort and classify documentation in a particular way.

Why Document Management is Important

• It allows to keep, store, and safeguard information
• Information can be easily and quickly found
• To comply with the law
• It can help in the decision-making process

Types of Files

1. Active: Documents that are currently being used and queried
2. Semi-active: Documents no longer effective but kept for legal reasons
3. Inactive: Documents not valid but with a historical or documentary value

File Systems

The file system is the criterion used for ordering information.

• Alphabetical: Information classified in the order of the alphabet. The ordering

Timeè t1 t2 t3 t4

checkpoint checkpoint checkpoint system crash

2.1 Describe the recovery needed according to the RDU (Recovery using Deferred Update) algorithm. You must indicate which transactions need to be undone/redone and which are ignored and need to be restarted. (2.5 points)

T4 and T5 are ignored because they did not reach their commit points. They need to be restarted.

T2 must be REDONE because it was committed after the last checkpoint.

2.2 Repeat the previous question using the RIU (Recovery using Immediate Update) algorithm. (2.5 points)

T4 and T5 are UNDONE because they did not reach their commit points and need to be restarted.

T2 must be REDONE because it was committed after the last checkpoint.

What is Gas Used for in a Residential Building?

Gas provides the energy needed for a comfortable home, powering systems like:

• Heating systems
• Water heating systems
• Kitchen stoves

Gas Supply Methods and Types

How is Gas Supplied?

Gas can be supplied through:

• Pipelines: Natural gas is transported via an underground network.
• Cylinders: Butane and propane are commonly transported in cylinders.

Which Gases are Used?

Common residential gases include:

• Natural gas (pipelines)
• Butane (cylinders)
• Propane (cylinders and pipes)

Gas System Components

General Valve

The general valve controls the entire gas supply to the building.

Main Gas Supply Unit

The main gas supply unit, typically located in the street, connects the main gas line to the individual property line. It's... Continue reading "Residential Gas Systems: A Comprehensive Guide" »

Lean systems are Operations systems that maximize the value added by each of a company’s Activities by removing waste and delays from them.

Toyota Production System (TPS)

Just-in-time (JIT) system

JIT philosophy – Eliminate waste or muda by cutting unnecessary capacity or inventory and Removing non-value-added activities

The goal is to Eliminate the eight types of waste, produce services and products only as Needed, and to continuously improve the value-added benefits of operations.

Close supplier ties

Look for ways to improve efficiency and reduce inventories Throughout the supply chain

JIT II: In-plant Representative

Supply Chain Considerations in Lean Systems

Small lot sizes: Reduce The average level of inventory. Pass Through system faster.... Continue reading "Aircraft systems" »