Notes, abstracts, papers, exams and problems of Technology

SOLAR ENERGY: 

WAYS OF USE:

Photothermal: Solar thermal energy: form of energy → takes advantages of solar energy to generate  thermal energy

• Flat solar collectors: 

  • box covered by insulating material with a fluid inside

  • the operation is based on the greenhouse effect→ heats the fluid

  • reach 60-100º

  • domestic us

• Concentration collector:

  • devices that concentrate solar radiation on a reduced surface

  • reach 300 ºC º

  • most common cylindrical - parabolic

  • industrial use

Photovoltaic: 

• Direct transformation from solar → electrical

• Photovoltaic cells

  • It’s a plate composed of electrodes that generates a direct current when photons incide on it

  • The energy can be stored (batteries) or direct use

  • Each cell produces 0,6V. That is why the are used panels of 32

List of Essential ICT Services

1. List the services that must be provided in the new ICT and indicates which are mandatory and which are optional. Solution:

• Service radio and television (RTV): capture, adapt and distribute radio and television signals that reach the building, so they can be interpreted by the user receivers.
• Telephone service available to the public (STDP): providing access to telephone and data transmission through the basic telephone network (TB) or integrated services digital network (ISDN).
• Service broadband telecommunications: to provide access to telecommunications services broadband (television, data, etc.), cable (TBA) or a wireless (SAI), promoting the development of the Digital Home.

2. Description of the Common Area of

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

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.

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" »

Conventional: Cut the scene from wider to narrower shots (master wide, medium, close Up…) and go back to the wider to reveal the outcome. Reveal: Cut the scene from narrower to wider. Matching action: Cut on movement. Overlap: Audio leads video or video leads audio. Match cut: metaphorically linking shots that share common characteristics (objects, Compositions, space...). Flash cutting: the duration of the shots is very brief.   Subliminal cutting: introducing a frame with a subliminal message. Cross cutting: alternating various lines of action. Elliptical editing: omitting time. Jump cut: cut to a shot that is very similar to the previous. Produces a “jumpy” image. Invisible editing: a cut that is not perceived by the viewer.