What to Look for Inside your Steam Boiler?

Written by Thomas Yoon

A steam boiler is a pressure vessel with a difference. The vessel is subjected to heat stress of expansion and contraction, internal and external corrosion, as well as intense heating on some of its surfaces.

If we are not careful,repparttar steam pressure can rise up very high, and it can become a potential bomb!

Because of this, steam boilers have to be built to certain regulatory codes, with regards to materials used in their construction, their design, and their installation.

Forrepparttar 133433 operator ofrepparttar 133434 steam boiler, it is essential thatrepparttar 133435 boiler be operated safely. Although many safety devices are fitted in allrepparttar 133436 boilers, they are not fail-proof. Humans are still needed to monitorrepparttar 133437 condition ofrepparttar 133438 boiler allrepparttar 133439 timerepparttar 133440 latter is operated, even if it is just to acknowledge an alarm buzzer or flashing light in a control room.

One ofrepparttar 133441 most important ingredients of a boiler isrepparttar 133442 water inside it. The use of untreated water will lead to scaling, corrosion or foaming. All of these have some detrimental effect onrepparttar 133443 boiler or steam systems.

So, always treatrepparttar 133444 water properly.

But however well you treatrepparttar 133445 water, you will never knowrepparttar 133446 condition insiderepparttar 133447 boiler until you actually see it.

The Fourth Law of Robotics - Part II

Written by Sam Vaknin

Note - Godel's Theorems

The work of an important, though eccentric, Czech-Austrian mathematical logician, Kurt Gödel (1906-1978) dealt withrepparttar completeness and consistency of logical systems. A passing acquaintance with his two theorems would have savedrepparttar 133432 architect a lot of time.

Gödel's First Incompleteness Theorem states that every consistent axiomatic logical system, sufficient to express arithmetic, contains true but unprovable ("not decidable") sentences. In certain cases (whenrepparttar 133433 system is omega-consistent), both said sentences and their negation are unprovable. The system is consistent and true - but not "complete" because not all its sentences can be decided as true or false by either being proved or by being refuted.

The Second Incompleteness Theorem is even more earth-shattering. It says that no consistent formal logical system can prove its own consistency. The system may be complete - but then we are unable to show, using its axioms and inference laws, that it is consistent

In other words, a computational system can either be complete and inconsistent - or consistent and incomplete. By trying to construct a system both complete and consistent, a robotics engineer would run afoul of Gödel's theorem.

Note - Turing Machines

In 1936 an American (Alonzo Church) and a Briton (Alan M. Turing) published independently (as is oftenrepparttar 133434 case in science)repparttar 133435 basics of a new branch in Mathematics (and logic): computability or recursive functions (later to be developed into Automata Theory).

The authors confined themselves to dealing with computations which involved "effective" or "mechanical" methods for finding results (which could also be expressed as solutions (values) to formulae). These methods were so called because they could, in principle, be performed by simple machines (or human-computers or human-calculators, to use Turing's unfortunate phrases). The emphasis was on finiteness: a finite number of instructions, a finite number of symbols in each instruction, a finite number of steps torepparttar 133436 result. This is why these methods were usable by humans withoutrepparttar 133437 aid of an apparatus (withrepparttar 133438 exception of pencil and paper as memory aids). Moreover: no insight or ingenuity were allowed to "interfere" or to be part ofrepparttar 133439 solution seeking process.

What Church and Turing did was to construct a set of allrepparttar 133440 functions whose values could be obtained by applying effective or mechanical calculation methods. Turing went further down Church's road and designedrepparttar 133441 "Turing Machine" – a machine which can calculaterepparttar 133442 values of allrepparttar 133443 functions whose values can be found using effective or mechanical methods. Thus,repparttar 133444 program runningrepparttar 133445 TM (=Turing Machine inrepparttar 133446 rest of this text) was really an effective or mechanical method. Forrepparttar 133447 initiated readers: Church solvedrepparttar 133448 decision-problem for propositional calculus and Turing proved that there is no solution torepparttar 133449 decision problem relating torepparttar 133450 predicate calculus. Put more simply, it is possible to "prove"repparttar 133451 truth value (orrepparttar 133452 theorem status) of an expression inrepparttar 133453 propositional calculus – but not inrepparttar 133454 predicate calculus. Later it was shown that many functions (even in number theory itself) were not recursive, meaning that they could not be solved by a Turing Machine.

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