Captains are officers in an army. In a navy, captains command an entire ship. A Navy Captain is equal to the army rank of colonel. Another type of captain is a commander of a ship who is not in the military.
There are also captains in other uniformed organisations, including the police. A leader of a sports team is also called a captain, as well as the pilot of an airliner.
Wire rope
Wire rope consists of several strands laid (or 'twisted') together like a helix. Each strand is likewise made of metal wires laid together like a helix. Initially wrought iron wires were used, but today steel is the main material used for wire ropes.
Modern wire rope was invented by the German mining engineer Wilhelm Albert in the years between 1831 and 1834 for use in mining in the Harz Mountains in Clausthal, Lower Saxony, Germany. It was quickly accepted because it was better than ropes made of hemp or to metal chains, such as had been used before.
Wilhelm Albert's first ropes consisted of wires twisted about a hemp rope core, six such strands then being twisted around another hemp rope core in alternating directions for extra stability. Earlier forms of wire rope had been made by covering a bundle of wires with hemp.
In America wire rope was later manufactured by John A. Roebling, forming the basis for his success in suspension bridge building. Roebling introduced a number of innovations in the design, materials and manufacture of wire rope.
Manufacturing a wire rope is similar to making one from natural fibres. The individual wires are first twisted into a strand, then six or so such strands again twisted around a core. This core may consist of steel, but also of natural fibres such as sisal, manila, henequen, jute, or hemp. This is used to cushion off stress forces when bending the rope.
The specification of a wire rope type, including the number of wires per strand, the number of strands, and the lay of the rope, are is documented using a commonly accepted coding system, with abbreviations. For example, the rope shown in the figure "Wire rope construction" is designated:
6x19 FC RH OL FSWR
Each of the sections of the wire rope designation described above is variable. There are therefore a large number of combinations of wire rope that can be specified in this manner. The following abbreviations are commonly used to specify a wire rope.
Liekkiö
Liekkiö ("flamey") or Ihtiriekko is a ghost of a bastard child in Finnish mythology.
Stories tells that a woman had sex with someone else than her husband. Maybe she did not even have a husband. She then get pregnant and gave birth to a baby. This way to make a baby was not accepted by church and society - that kind of baby is called bastard. Mother had to kill her bastard child to avoid being blamed by priests or other people. Mother then buried child outside graveyard and without priests blessing the body. Soul of baby could not go to heaven because his/her body was not at graveyard and was not blessed by a priest. This is why she became a ghost.
This ghost could make terrible noise until somebody dugs up his/her body and buries it in graveyard. Such ghost people call Ihtiriekko. Ghosts could also be quiet, but she/he might be seen as a flame in forest, like will o' the wisp. Such ghost people call Liekkiö.
Bastard
A bastard is a person who was born of parents who are not married to one another. It is considered by some cultures and individuals as a nasty or insulting word today, or sometimes even profanity, with the term illegitimate being a little more polite. Some cultures see illegitimate children as dirty or bad, and only accept sexual relations between married couples.
Gödel number
In formal number theory a Gödel numbering is a function which assigns to each symbol and formula of some formal language a unique natural number called a Gödel number (GN). The concept was first used by Kurt Gödel for the proof of his incompleteness theorem.
A Gödel numbering can be interpreted as an encoding where a number is assigned to each symbol of a mathematical notation, and a stream of natural numbers can then represent some form or function. A numbering of the set of computable functions can then be represented by a stream of Gödel numbers (also called effective numbers). Rogers' equivalence theorem states criteria for which those numberings of the set of computable functions are Gödel numberings.
Given a countable set "S", a Gödel numbering is an injective function
with both "f" and formula_2 (the inverse of "f") being computable functions.
One of the simplest Gödel numbering schemes is used every day: The correspondence between integers and their representations as strings of symbols. For example, the sequence 2 3 is understood, by a particular set of rules, to correspond to the number twenty-three. Similarly, strings of symbols from some alphabet of "N" symbols can be encoded by identifying each symbol with a number from 0 to "N" and reading the string as the base "N"+1 representation of an integer.
Formal language
In mathematics, computer science and linguistics, a formal language is one that has a particular set of symbols, and whose expressions are made according to a particular set of rules. The symbol formula_1 is often used as a variable for formal languages in logic.
Unlike natural languages, the symbols and formulas in formal languages are syntactically and semantically related to one another in a precise way. As a result, formal languages are completely (or almost completely) void of ambiguity.
Some examples of formal languages include:
A formal language can be specified in a great variety of ways, such as:
Alphabet (computer science)
In computer science, an alphabet is a finite non-empty set. The elements of an alphabet are called the letters or symbols of the alphabet.
An example of an alphabet is formula_1 which may be used for Morse code or "{begin, if, else, for, while}" which may be the keywords of a Programming language.
The set of natural numbers is not an alphabet because as it is not finite.
The alphabet which is used the most in computer science is "{0,1}". It is called the binary alphabet because it contains two symbols. An alphabet can be used to make a string (or word). This is a finite Sequence of letters from the alphabet. For example, a string of length 5 over "{0,1}" is "01101".
The empty string is the string containing no letters (it is often written as formula_2). The empty string is a string over any alphabet.
If we have an alphabet called formula_3. Then we write the set of "all" strings that can be made from formula_3 as formula_5. This is called the Kleene star (or Kleene closure) of formula_3. It is named after the mathematician Stephen Cole Kleene.
The Kleene star of the binary alphabet is formula_7. The three dots after 001, show that we cannot write the Kleene star of an alphabet in full because it is an infinite set.
Alphabets are important because they are used in studying formal languages, finite automata and very difficult questions in computer science about what can be computed and what can not.
Empty string
The empty string is the unique string of no characters over some alphabet Σ. It is written as "ε" or "λ". The length of this empty string is 0.
In simple words, given some characters of an alphabet, the empty string is the "word" that can be made if no letters are used. There is of course only one such word.
Under concatenation, the empty string is the identity element of the free monoid on Σ. That is, for any string "s", "s"ε = ε"s" = s.
In many programming languages, the empty string is written with two double quotes: """". The empty string is also sometimes noted by the Greek letter λ.
In C, the empty string is represented by a character array with a null character in the zeroeth position. Note that all strings in C are terminated by a null character.
Old Possum's Book of Practical Cats