Knowledge N Fact4u

Single generator sets of over 600 MW are now used in the UK, though there are many smaller generators in use. A 600 MW generator can supplythe average needs of over 1 million UK households. Three or four such generators are typically installed in a single large coal-fired station which isoften sited close to a coal mine, away from the city dwellers who consume the electricity. Such generators are usually driven by a compound arrangement of highpressure, intermediate-pressure and low-pressure turbines, increasing in size as the pressure decreases. Modern turbines rotate in a speed range from 1500 to 3500 r.p.m., usually 3000 r.p.m. for the UK’s 50 Hz system. For large coal-fired plant the steam pressure could be 25 megapascals (MPa) with steam temperatures of 500–600 °C to improve the thermodynamic efficiency. In nuclear reactors, which operate under less demanding conditions, the steam is superheated to about 5 MPa and 300 °C. Modern water tube boilers are complex and have

•We spend about one-third of our lives sleeping.  •Why do we invest so much time in sleep?  •The most straight forward answer is that, sleep is restorative, and it replenishes the body's energy stores.  •However, intense neural activity during rapid eye movement (REM) sleep, the stage in which most dreams occur, suggests there may be more to the story.  •One theory, which by far has the largest body of evidence, is that sleep plays a critical role in learning and consolidating memories.  •It is probably why infants and toddlers need up to 14 hours of sleep a day, with half of it spent in REM sleep.  •In adults, dreams may also play a role in brain plasticity and learning, which is why sleep-deprived adults perform worse in memory tests and tasks. 

5G is bringing a wide range of technology inventions in both the 5G NR (New Radio) air interface design as well as the 5G NextGen core network. The new 5G NR air interface introduces many foundational wireless inventions, and in our opinion, the top five are: Scalable OFDM numerology with 2n scaling of subcarrier spacing Flexible, dynamic, self-contained TDD subframe design Advanced, flexible LDPC channel coding Advanced massive MIMO antenna technologies Advanced spectrum sharing techniques

The average heart is the size of a fist in an adult. Your heart will beat about 115,000 times each day. Your heart pumps about 2,000 gallons of blood every day. An electrical system controls the rhythm of your heart. ... The heart can continue beating even when it's disconnected from the body.

1)The word Christmas originates from the words Christ's Mass. In old English (first recorded in 1038) it was referred to as Cristesmæsse, which literally means 'Christian Mass'. 2)A common figure known throughout the world and associated with Christmas is Santa Claus. Other popular Christmas figures include Christkind, Saint Nicholas, and Father Christmas. 3)Anglo-Saxons referred to the holiday as 'midwinter' or 'nativity'. 4)In order for Santa to visit all the homes on Christmas Eve he would have to visit 822 homes each second. 5)The tradition of hanging stockings comes from a Dutch custom. They would leave shoes full of food for St. Nicolas' donkeys and St. Nicholas would then leave small gifts in return. 6)The world's biggest snowman was 113 feet tall and was built in Maine. 7)The Christmas wreath is symbolic of Jesus. The red berries symbolize his blood and the holly represents the crown of thorns. 8)The best-s

∆∆Optical fibre links are being increasingly used for both short-distance communications, such as for local area networks (LANs), and long-distance communications. This arises from the fundamental advantages of optical f ibre communications:  • They are low cost.  • They are robust when packaged.  • They can have very wide optical bandwidths (GHz) and long communication links (hundreds of kilometres).  • They are insensitive to electromagnetic interference.  ∆∆This has led to the wide range of intercontinental communication links which are several thousand kilometres long, which distance considerably exceeds the maximum length of optical fibre that can be manufactured. It also exceeds the maximum link length over which an optical signal can be propagated without periodic amplification or regeneration. The environment is also somewhat harsh and remote, requiring high reliability and robust packaging. ∆∆The highest frequency was of the order of 1000 GHz. If the fr

## Huffman  coding is a statistical data compression technique, which gives a reduction in the average code length, used to represent the symbols of an alphabet. The Huffman code is an example of a code that is optimal in the case where all symbol probabilities are integral powers of 0.5. A Huffman code can be built in the following manner:  1. Rank all symbols in order of probability of occurrence. 2. Successively combine the two symbols of the lowest probability to form a new composite symbol; eventually to build a binary tree where each node is the probability of all nodes beneath it.  3. Trace a path to each leaf, noticing the direction at each node.   ## For  a given probability distribution, there are many possible Huffman codes, but the total compressed length will be the same. This technique is used in most archivers. This is a means of producing a variable length code which has an average length  l close to the average information contained in a message.  l will al

££) In  the early nineteenth century, all of the essential components necessary to construct an electrical communication system had been discovered. The most important of these were the battery by Volta, the relationship between electric current and magnetism by Oersted, and the electromagnet by Henry. It now remained for someone to find a practical method to combine these technologies into a working communication system. ££)Some  commercial electrical communications systems existed in Europe as early as the 1830s. A classic example of this is the English ‘Needle Telegraph’. The needle telegraph required two or more lines to form a complete circuit. It was relatively slow and the design of the transmitting and receiving instruments was complex. Something simple and efficient was needed. ££)The  Morse system of telegraphy was invented by Samuel Finley Breese Morse (an American painter and founder of the National Academy of Design in New York) in the 1840s in the United State

This is of interest in many applications; an example is sending a large document by email. The document may be several hundred kilobytes in size and to send it by email over a telephone line using a modem operating at 28.8 kbps may take a considerable time. If the data are compressed, the file can in certain cases be reduced in size by a factor of over 10, which would reduce the time taken to transmit the file, thus improving the convenience and minimizing cost. If the source information contains redundant information, data compression can shorten the message by removing redundancy. An example would be sending a text file over a communications link where the source device removes redundant characters before transmission. If the file contains sequences that are repeated, such as several space characters in a row, then instead of transmitting each of them the number of spaces could be transmitted. At the receiver the reverse process would allow the original document to be recovered. This