text:
Haskell/Lists and tuples

Haskell uses two fundamental structures for managing several values: lists and tuples. They both work by grouping multiple values into a single combined value.

Lists
Let's build some lists in GHCi:

The square brackets delimit the list, and individual elements are separated by commas. The only important restriction is that all elements in a list must be of the same type. Trying to define a list with mixed-type elements results in a typical type error:

Building lists
In addition to specifying the whole list at once using square brackets and commas, you can build them up piece by piece using the  operator pronounced "cons". The process of building up a list this way is often referred to as consing. This terminology comes from LISP programmers who invented the verb "to cons" (a mnemonic for "constructor") to refer to this specific task of prepending an element to a list.

When you cons something on to a list, you get back another list. Thus, you can keep on consing for as long as you wish. Note that the cons operator evaluates from right to left. Another (more general) way to think of it is that it takes the first value to its left and the whole expression to its right.

In fact, Haskell builds all lists this way by consing all elements to the empty list,. The commas-and-brackets notation are just syntactic sugar. So  is exactly equivalent to

You will, however, want to watch out for a potential pitfall in list construction. Whereas  is perfectly good Haskell,   is not:

produces a familiar-looking type error message. It tells us that the cons operator  (which is really just a function) expected a list as its second argument, but we gave it another   instead. only knows how to stick things onto lists.

So, when using cons, remember:

 * The elements of the list must have the same type.
 * You can only cons  something onto a list, not the other way around (you cannot cons a list onto an element). So, the final item on the right must be a list, and the items on the left must be independent elements, not lists.

Strings are just lists
As we briefly mentioned in the Type Basics module, strings in Haskell are just lists of characters. That means values of type String can be manipulated just like any other list. For instance, instead of entering strings directly as a sequence of characters enclosed in double quotation marks, they may also be constructed through a sequence of Char values, either linked with  and terminated by an empty list or using the commas-and-brackets notation.

Using double-quoted strings is just more syntactic sugar.

Lists of lists
Lists can contain anything — as long as they are all of the same type. Because lists are things too, lists can contain other lists! Try the following in the interpreter:

Lists of lists can be tricky sometimes because a list of things does not have the same type as a thing all by itself. The type  is different from. Let's sort through these implications with a few exercises:

Lists of different types of things cannot be consed, but the empty list can be consed with lists of anything. For example,  is valid and will produce , and   is valid and will produce  , but   will produce an error message.

Lists of lists allow us to express some kinds of complicated, structured data (two-dimensional matrices, for example). They are also one of the places where the Haskell type system truly shines. Human programmers (including this wikibook co-author) get confused all the time when working with lists of lists, and having restrictions on types often helps in wading through the potential mess.

A different notion of many
Tuples offer another way of storing multiple values in a single value. Tuples and lists have two key differences:

 * Tuples have a fixed number of elements (immutable); you can't cons to a tuple. Therefore, it makes sense to use tuples when you know in advance how many values are to be stored. For example, we might want a type for storing 2D coordinates of a point. We know exactly how many values we need for each point (two – the x and y coordinates), so tuples are applicable.

 * The elements of a tuple do not need to be all of the same type. For instance, in a phonebook application we might want to handle the entries by crunching three values into one: the name, phone number, and the number of times we made calls. In such a case the three values won't have the same type, since the name and the phone number are strings, but contact counter will be a number, so lists wouldn't work.

Tuples are marked by parentheses with elements delimited by commas. Let's look at some sample tuples:

The first example is a tuple containing two elements: True and 1. The next example again has two elements: "Hello world" and False. The third example is a tuple consisting of five elements: 4 (a number), 5 (another number), "Six" (a string), True (a boolean value), and 'b' (a character).

A quick note on nomenclature: In general you use n-tuple to denote a tuple of size n. Commonly, we call 2-tuples (that is, tuples with 2 elements) pairs and 3-tuples triples. Tuples of greater sizes aren't actually all that common, but we can logically extend the naming system to quadruples, quintuples, and so on.

Tuples are handy when you want to return more than one value from a function. In many languages, returning two or more things at once often requires wrapping them up in a single-purpose data structure, maybe one that only gets used in that function. In Haskell, we would return such results as a tuple.

Tuples within tuples (and other combinations)
We can apply the same reasoning to tuples about storing lists within lists. Tuples are things too, so you can store tuples within tuples (within tuples up to any arbitrary level of complexity). Likewise, you could also have lists of tuples, tuples of lists, and all sorts of related combinations.

The type of a tuple is defined not only by its size, but, like lists, by the types of objects it contains. For example, the tuples  and   are fundamentally different. One is of type, whereas the other is. This has implications for building up lists of tuples. We could very well have lists like, but Haskell cannot have a list like.

Retrieving values
For lists and tuples to be useful, we will need to access the internal values they contain.

Let's begin with pairs (i.e. 2-tuples) representing the (x, y) coordinates of a point. Imagine you want to specify a specific square on a chess board. You could label the ranks and files from 1 to 8. Then, a pair  could represent the square in rank 2 and file 5. Say we want a function for finding all the pieces in a given rank. We could start with the coordinates of all the pieces and then look at the rank part and see whether it equals whatever row we want to examine. Given a coordinate pair  of a piece, our function would need to extract the   (the rank coordinate). For this sort of goal, there are two standard functions,  and , that retrieve the first and second elements out of a pair, respectively. Let's see some examples:

Note that these functions, by definition, only work on pairs.

For lists, the functions  and   are roughly analogous to   and. They disassemble a list by taking apart what  joined. evaluates to the first element of the list, while  gives the rest of the list.

Pending questions
The four functions introduced here do not appear to fully solve the problem we started this section with. While  and   provide a satisfactory solution for pairs, what about tuples with three or more elements? And with lists, can we do any better than just breaking them after the first element? For the moment, we will have to leave these questions pending. Once we do some necessary groundwork, we will return to this subject in future chapters on list manipulation. For now, know that separating head and tail of a list will allow us to do anything we want.

Polymorphic types
Recall that the type of a list depends on the types of its elements and is denoted by enclosing it in square brackets:

Lists of  are a different type than lists of   (which is the same as a list of   because   and   are synonyms). Since functions only accept arguments of the types specified in the type of the function, that might lead to some complications. For example, consider the case of. Given that,   and   are different types, it seems we would need separate functions for every case –  ,  ,  , and so on… That, however, would be not only very annoying but also rather senseless. After all, lists are assembled in the same way regardless of the types of the values they contain, and so we would expect the procedure to get the first element of the list would remain the same in all cases.

Fortunately, we do have a single function, which works on all lists:

How can that possibly work? As usual, checking the type of  provides a good hint:

The  in the signature is not a type – remember that type names always start with uppercase letters. Instead, it is a type variable. When Haskell sees a type variable, it allows any type to take its place. In type theory (a branch of mathematics), this is called polymorphism: functions or values with only a single type are called monomorphic, and things that use type variables to admit more than one type are polymorphic. The type of, for instance, tells us that it takes a list  of values of an arbitrary type  and gives back a value of that same type.

Note that within a single type signature, all cases of the same type variable must be of the same type. For example,

means that  takes an argument of any type and gives something of the same type as the result, as opposed to

which means that  takes an argument of any type and gives a result of any type which may or may not match the type of whatever we have for. The different type variables do not specify that the types must be different, it only says that they can be different.

Example: and
As we saw, you can use the  and   functions to extract parts of pairs. By now, you should already be building the habit of wondering "what type is this?" for every function you come across. Let's consider the cases of  and. These two functions take a pair as their argument and return one element of this pair. As with lists, the type of a pair depends on the type of its elements, so the functions need to be polymorphic. Also remember that pairs (and tuples in general) don't have to be homogeneous with respect to internal types. So if we were to say:

That would mean  would only work if the first and second part of the pair given as input had the same type. So the correct type is:

If you knew nothing about  and   other than the type signatures, you might still guess that they return the first and second parts of a pair, respectively. Although that is correct, other functions may have this same type signature. All the signatures say is that they just have to return something with the same type as the first and second parts of the pair, respectively.

Summary
This chapter introduced lists and tuples. The key similarities and differences between them are:

 * 1) Lists are defined by square brackets and commas :.
 * 2) * Lists can contain anything as long as all the elements of the list are of the same type.
 * 3) * Lists can also be built by the cons operator,, but you can only cons things onto lists.
 * 4) Tuples are defined by parentheses and commas :
 * 5) * Tuples can contain anything, even things of different types.
 * 6) * The length of a tuple is encoded in its type; tuples with different lengths will have different types.
 * 7) Lists and tuples can be combined in any number of ways: lists within lists, tuples within lists, etc, but their criteria must still be fulfilled for the combinations to be valid.

title: Haskell/Lists and tuples


text:
Marketing

Creation, Pricing, Promotion, and Distribution of Goods, Services, and Ideas

Table of Contents

 * 1) /Introduction/
 * 2) /Marketing Goals/
 * 3) /Marketing Strategy/
 * 4) /Marketing Plan/
 * 5) /Targeting & Segmentation/
 * 6) /Consumer Behavior/
 * 7) /Product Development/
 * 8) /Market Research/
 * 9) /Marketing Ethics/

Resources

 * Wikiversity: (School of Business)

Marketing Marketing fa:بازاریابی Pemasaran การตลาด

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Marketing


text:
User:Bamos~enwikibooks

Hey there.

title: User:Bamos~enwikibooks


text:
User:Kowey/HaskellRedesign

The Book
This book is divided into two tracks. The beginner's track (left) will introduce you to the very basics of the language and some of most frequently used libraries. This will enable you to build simple programs and prepare you for the advanced track. The advanced track (right) introduces functional programming concepts like monads, some new features of Haskell, such as Generalised Algebraic Data Types. At the very end of this book, we also have a set of chapters on the more day-to-day issues of working with Haskell, issues such as making use of the stardard library, building graphical interfaces or working with databases. You should be able to jump directly to this chapter from the basic track.

Please contribute! Everyone, regardless of Haskell competency, can help out. Spend five minutes improving a module and save someone else hours of time. Check out the notes for contributors.

{|width="100%" cellspacing="0" cellpadding="0" style="margin-top:0.8em;margin-bottom:0.8em" {|width="100%" cellspacing="0" cellpadding="5" style="background:honeydew"
 * width="50%" valign="top" style="border:1px solid MediumAquamarine;background:honeydew"|

 * style="font-size:95%;"|

Haskell Basics

 * /Getting set up/
 * /Variables and functions/
 * /List basics/
 * /Next steps/
 * /Type basics/
 * /Recursion/
 * /Lists/

 * style="font-size:95%;border-top:1px dashed MediumAquamarine"|
 * style="font-size:95%;border-top:1px dashed MediumAquamarine"|

Elementary Haskell

 * /A Miscellany of Types/
 * /List Processing/
 * /More on functions/
 * /Pattern matching/
 * /Control structures/
 * Understanding Haskell indentation rules

 * style="font-size:95%;border-top:1px dashed MediumAquamarine"|
 * style="font-size:95%;border-top:1px dashed MediumAquamarine"|

Intermediate Haskell

 * /Simple input and output/
 * /Type Declarations/
 * /More on Datatypes/
 * /Class Declarations/
 * /Classes and Types/

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 * }
 * style="border:1px solid SlateBlue;background:#F7F7FF"|
 * style="border:1px solid SlateBlue;background:#F7F7FF"|

 * style="font-size:95%"|

Monads

 * /Understanding monads/
 * /Advanced monads/
 * Additive monads (MonadPlus)
 * Transformers - putting monads together
 * Monads in practice

 * style="font-size:95%;border-top:1px dashed SlateBlue"|

Advanced Haskell

 * /Arrows/
 * /Understanding arrows/
 * Continuation passing style
 * /Functional dependencies/
 * /Strictness/
 * /Laziness revisited/

 * style="font-size:95%;border-top:1px dashed SlateBlue"|
 * style="font-size:95%;border-top:1px dashed SlateBlue"|

Fun with Types

 * /Existentially quantified types/
 * /Polymorphism/
 * /Phantom types/
 * Generalised algebraic data types

 * }
 * }

Haskell in Practice
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 * width="50%" valign="top" style="border:1px solid gold;background:cornsilk"|

 * style="font-size:95%;"|

Libraries

 * Modules and libraries
 * The Hierarchical Libraries
 * Lists - Arrays - Maybe - Maps
 * Random Numbers

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 * }
 * style="border:1px solid gold;background:cornsilk"|
 * style="border:1px solid gold;background:cornsilk"|

 * style="font-size:95%"|

Tutorials

 * Building a standalone application
 * /Testing and Debugging/
 * Graphical user interfaces
 * Database libraries
 * Distributing your software with the Cabal

 * }
 * }

title: User:Kowey/HaskellRedesign


text:
User talk:Lakeland~enwikibooks

Hello, and welcome to wikibooks! I see that you've started a new book, Marketing. Starting a new book can be a difficult and time-consuming task. If you need any help with this project, let me know. If you have any questions about wikibooks in general, I can help you with that also. Good luck! --Whiteknight (talk) (projects) 22:00, 10 July 2006 (UTC)

Your account will be renamed
Hello,

The developer team at Wikimedia is making some changes to how accounts work, as part of our on-going efforts to provide new and better tools for our users like cross-wiki notifications. These changes will mean you have the same account name everywhere. This will let us give you new features that will help you edit and discuss better, and allow more flexible user permissions for tools. One of the side-effects of this is that user accounts will now have to be unique across all 900 Wikimedia wikis. See the announcement for more information.

Unfortunately, your account clashes with another account also called Lakeland. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Lakeland~enwikibooks that only you will have. If you like it, you don't have to do anything. If you do not like it, you can pick out a different name.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:24, 17 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 05:11, 19 April 2015 (UTC)

title: User talk:Lakeland~enwikibooks


text:
Chess Opening Theory/1. d4/1...Nf6/2. c4/2...g6

=King's Indian Defence=

2...g6
With 2...g6, Black commits to a hypermodern development strategy. They will fianchetto their dark-squared bishop with ...Bg7 and attempt to exert pressure on White's center with pieces and timely pawn breaks. After 2...g6 certain themes are already evident. Preservation of the dark-square bishop will be vital for Black's safety after castling kingside. 2...g6 weakens the dark squares around Black's king; without the dark-square bishop to control squares like f6 and h6, these weaknesses can be fatal. The g7 bishop is not purely a defensive piece, however. White must be aware that opening the center by pawn exchanges may very well unleash the bishop's power by giving it a clear diagonal towards White's queenside.

2...g6 will almost certainly lead to either a King's Indian Defence or a Grunfeld Defence.

In the King's Indian Defence, Black castles kingside as quickly as possible with a fianchettoed structure, in doing so it will allow White to have pawn presence in the centre. Black will then do their best to claim as much as they can back with their own pawns, often chipping away at the residual White presence. A strategist's playground.

While in the Grunfeld, Black uses 2...g6 to wait for Nc3 by White where he will follow with ...d5. Black's play will be the dark diagonal, usually with the help of the move ...c5, while White's advantage will be his broad centre - Hypermodernism exemplified.

Theory table
.

'''1. d4 Nf6 2. c4 g6'''


text:
Talk:Asymptote

I went ahead and moved this to Asymptote because the how-to section seemed to indicate that this was more than just a simple reference. Feel free to move it back after signing up for a free account. Also note that the page The asymptotic reference/Command/Math/Intersect is not linked to anywhere in this book. See WB:NP to learn how to link to subpages. You can renamed pages by pressing Alt + M after logging in. Good luck on this project, hagindaz 00:05, 11 July 2006 (UTC)

To help making the command pages run

asy -l | grep

and add the functions to the /Command/ / page along with info and examples.

title: Talk:Asymptote


text:
Haskell/Strictness

Difference between strict and lazy evaluation
Strict evaluation, or eager evaluation, is an evaluation strategy where expressions are evaluated as soon as they are bound to a variable. For example, with strict evaluation, when  is read, 3 * 7 is immediately computed and 21 is bound to x. Conversely, with lazy evaluation values are only computed when they are needed. In the example, 3 * 7 isn't evaluated until it's needed, like if you needed to output the value of x.

Why laziness can be problematic
Lazy evaluation often involves objects called thunks. A thunk is a placeholder object, specifying not the data itself, but rather how to compute that data. An entity can be replaced with a thunk to compute that entity. When an entity is copied, whether or not it is a thunk doesn't matter - it's copied as is (on most implementations, a pointer to the data is created). When an entity is evaluated, it is first checked if it is thunk; if it's a thunk, then it is executed, otherwise the actual data is returned. It is by the magic of thunks that laziness can be implemented.

Generally, in the implementation the thunk is really just a pointer to a piece of (usually static) code, plus another pointer to the data the code should work on. If the entity computed by the thunk is larger than the pointer to the code and the associated data, then a thunk wins out in memory usage. But if the entity computed by the thunk is smaller, the thunk ends up using more memory.

As an example, consider an infinite length list generated using the expression. The size of the list is infinite, but the code is just an add instruction, and the two pieces of data, 1 and 0, are just two Integers. In this case, the thunk representing that list takes much less memory than the actual list, which would take infinite memory.

However, as another example consider the number generated using the expression. The value of that number is 54, but in thunk form it is a multiply, an add, and three numbers. In such a case, the thunk loses in terms of memory.

Often, the second case above will consume so much memory that it will consume the entire heap and force the garbage collector. This can slow down the execution of the program significantly. And that, in fact, is the main reason why laziness can be problematic.

Additionally, if the resulting value is used, no computation is saved; instead, a slight overhead (of a constant factor) for building the thunk is paid. However, this overhead is not something the programmer should deal with most of the times; more important factors must be considered and may give a much bigger improvements; additionally, optimizing Haskell compilers like GHC can perform 'strictness analysis' and remove that slight overhead.

title: Haskell/Strictness


text: Category:Book:Windows Programming/Stubs

title: Category:Book:Windows Programming/Stubs


text:
Music Theory/Modulation

Modulation is the process of changing key center. Modulation occurs in a number of ways, most of them involving some way of making the current key ambiguous and reaching a cadence in a new key. The key chosen is usually one closely related to the original key, those that share the key signature or have only one sharp or flat different in the key signature (for example, in C major, A minor, G major, and F major are all closely related keys). Modulation to other keys is not unknown, however, particularly in the Romantic era.

There are several means used to modulate. One is simply to introduce a new key, though this does not always sound very convincing and many consider it quite crude. In classical music, modulation is usually prepared and carried out through the use of pivot chords, which exist in both the starting key and the intended destination. Especially during the Romantic era, the possibilities of chromatic pivot chords, such as the diminished seventh, were heavily exploited.

Pivot chord
A pivot chord is a chord that is common to both the key you are moving from and the key you are moving into. The pivot chord begins as a particular chord in the original key (eg. iv) and is then used as a different chord in the new key (eg. ii). This creates a smooth transition to the new key.

Eg. To modulate from C major to G major, the chord a- is common to both keys, and can be used as a pivot chord as follows:

C -> a -> D7 -> G

(I -> vi/ii -> V7 -> I)

Another method of modulation is to treat a major chord in a given key as the dominant chord in a new key by adding a minor 7th above. Commonly, the tonic chord is used like this to modulate to the sub-dominant:

Eg. in C major, modulating to F major

C -> C7 -> F

(I -> I7/V7 -> I)

Or to modulate to Bb, one may follow this progression:

C -> F -> F7  -> Bb

(I -> IV -> IV7/V7 -> I)

Uses of modulation
Modulation is integral to sonata form, where a modulation to a (usually) related key in the exposition sets up an important tonal contrast in the development. Modulation is also used in other forms like the fugue and rondo to create contrast within unity.

title: Music Theory/Modulation


text:
Talk:Measure Theory

All commentaries are welcome --Bunder 05:08, 11 July 2006 (UTC)

The sections need proof-reading, especially for grammar and formality of language -- ed. 17/4/2007

title: Talk:Measure Theory


text:
Wikijunior:United States Charters of Freedom/National Archives and Records Administration

The United States National Archives and Records Administration (NARA) is an independent agency of the United States federal government charged with preserving and documenting government and historical records. It also works to increase public access to those documents. NARA is officially responsible for publishing acts of Congress, presidential proclamations and executive orders, and federal regulations. The agency often works closely with scholars to facilitate their studies. NARA is most famously known as the housing of the United States Charters of Freedom.

History
In the past, each branch and agency of the U.S. government was responsible for maintaining its own documents, which often resulted in the loss and destruction of records. Congress established the National Archives in 1934 to centralize federal record keeping, with the Archivist of the United States as its chief administrator. The National Archives was incorporated into the General Services Administration in 1949, but in 1985 it was made an independent agency known as NARA.

Most of the documents in the care of NARA are in the public domain, as works of the federal government are excluded from copyright protection. However, some documents that have come into the care of NARA from other sources may still be protected by copyright or donor agreements. NARA also stores classified documents and its Information Security Oversight Office monitors and sets policy for the U.S. government's security classification system.

National Archives Building
The National Archives Building, known informally as Archives I, located north of the National Mall on Constitution Avenue in Washington, D.C., opened as its original headquarters in 1935. It houses the Charters of Freedom: the ../Declaration of Independence/, the ../Constitution/, and the ../Bill of Rights/. These are displayed to the public in the main chamber of the National Archives, which is called the Rotunda for the Charters of Freedom. Flash photography of the documents is prohibited. There are no lines at the National Archives, and visitors are allowed to walk from document to document as they wish.

The National Archives Building also exhibits other important American historical documents such as the Louisiana Purchase and the Emancipation Proclamation, as well as collections of photography and other historically and culturally significant American artifacts.

National Archives at College Park
Due to space constraints, NARA opened a second facility, known informally as Archives II, in 1994 at College Park, Maryland, where it is now based. There are also twelve Regional Archives facilities across the country and two major facilities in St. Louis, Missouri which comprise the National Personnel Records Center. However, the National Archives Building in downtown Washington, D.C. still contains such record collections as all existing Federal Census records, Ship Passenger Lists, military unit records from the American Revolution up to the Philippine-American War, records of the Confederate Government, the Freedmen's Bureau records and pension/land records.

1973 National Archives Fire
A disastrous fire that occurred at the National Personnel Records Center (NPRC), a facility controlled by NARA, in St. Louis, Missouri, on July 12, 1973. NPRC, the custodian of military service records, lost approximately 16-18 million Official Military Personnel Files as a result of the fire.

Affected Records
The affected record collections are described below.

 * U.S. Army personnel discharged November 1, 1912, to January 1, 1960
 * U.S. Air Force personnel discharged September 25, 1947, to January 1, 1964, with names alphabetically after Hubbard, James E.
 * Some U.S. Army Reserve personnel who received final discharge as late as 1964
 * Various U.S. Navy, United States Coast Guard, and U.S. Marine Corps records which were out of file and were caught in the section of the building which experienced the most damage in the fire.

Cause of Fire
The exact cause of the 1973 National Archives Fire was never fully determined. An investigation in 1975 revealed that the affected floor, where the fire had started, had been under extreme temperature with little or no ventilation. It was speculated that air pressure on the floor had reached such a level that, combined with the very high temperatures in the enclosed space, the brittle and dry records began to catch fire. The investigation also did not rule out that the fire had been contributed to, if not directly started by, cigarette embers which were present in several trashcans.

Damage and Reconstruction
The 1973 fire destroyed the entire 6th floor of the National Personnel Records Center. Damage from the fire can still be seen today. In 1974, a massive reconstruction effort was begun to restore the service records which were destroyed in the 1973 fire. In most cases where a military record has been presumed destroyed, NPRC is able to reconstruct basic service information, such as military date of entry, date of discharge, character of service, and final rank.

Conspiracy Theories
In recent years, some conspiracy theories have emerged to explain the 1973 National Archives Fire. No such claims are taken very seriously by the United States government. Such conspiracy accusations include:

 * The Federal Government intentionally started the 1973 National Archives Fire as a cover to destroy unwanted military files, erase certain records from the Second World War, and to reduce budget costs by destroying a floor of an under budgeted federal building.
 * Agents of anti-government organizations broke into NPRC and started the 1973 fire as a terrorist attack.
 * The 1973 Fire did not happen at all, and that the explanation of a fire destroying millions of military records is a lie conceived by the Federal Government to cut costs and avoid public requests for the older military files.
 * The Church of Scientology started the fire in an attempt to destroy embarrassing records relating to L. Ron Hubbard's World War II service. The basis of this conspiracy theory seems to stem from the later incidents that occurred during Operation Snow White, and from the coincidence that certain records were only destroyed alphabetically from "Hubbard, James E" (although Hubbard had served in the Navy, not the Air Force).

Resources

 * The Wikipedia article
 * NARA official site
 * National Archives 1973 NPRC Fire Information Page


text:
Super NES Programming/Introduction to assembly

It would be convenient if this Wikibook could assume that you have learned some other form of assembly language. This tutorial will try to introduce you to the practice of programming the SNES at the lowest level possible.

Registers
Registers are at the core of any processor, and are basically locations in memory which serve a special purpose. All instructions have an effect on one or more of these registers. Even the nop instruction, which does nothing, increments the Program Counter register.

All of the SNES registers are either 8 bits or 16 bits. Registers A, X, Y may be set to be either 8 or 16 bits.

Hexadecimal notation
In low-level programming, it is common for programmers to type numbers in hexadecimal notation. This means that values can have a base of 16. In other words, each digit can have 16 possible values: 0-9, A,B,C,D,E,F. This makes it easy to represent and manipulate individual bits.

In SNES assembly, hex values are specified with the $ prefix.

Instructions
Instructions are a breakdown of machine code. For the SNES, they consist of a 1-byte opcode followed by a 0-3 byte operand. Full instructions may be known as words. For example, the instruction "ADC $3a" occupies 2 bytes in memory, and if assembled, it would be stored as "E6 3A".

Most instructions that are at least 2 bytes long have more than one addressing mode. Addressing modes are put in place so basic instructions may be interpreted correctly given a wide range of operands. The SNES addressing modes may be found at the end of the 65c816_reference

Arithmetic/logical instructions
Most arithmetic instructions perform an arithmetic operation on A (the accumulator) and another value and store the result back in A. Addition, for instance, is represented by "ADC".

ADC, SBC (subtraction), AND, ORA (bitwise OR), EOR (bitwise XOR) are the most basic arithmetic instructions. The most common addressing modes for these are: See also 65c816 Reference: Addressing Modes


text: Category:Book:Jini and Network Computing


text: Category:Subject:Judaism

title: Category:Subject:Judaism


text:
User:Stuhacking~enwikibooks

Same Stuhacking as on Wikipedia :-)

title: User:Stuhacking~enwikibooks


text:
Blender 3D: Noob to Pro/Add some depth with stereo

This tutorial contains some tips for how to work with stereo images.

Stereo viewing is to see the same thing from two slightly different angles. This is what humans normally do with their two eyes. There are many ways to view a stereo image. A perfect method is to use a stereo monitor. But they are quite expensive, and many are of very low quality. In the other end of the price-scale you can use crossviewing. Put the two images next to each other, and look at one with one eye, and the other with the other eye. Needs a bit of practice though. A popular solution is red/blue anaglyph glasses, but they give very bad colors.

The stereo camera
I wanted a stereo camera rig that was easy to work with. It should have three cameras (center, left, and right), have an easy way to set separation (should be 1/30 of the distance) and the center cam should be used to control position etc, the two others should just follow.

Manually

 * 1) Reset the cameras position, rotation and size (you can use,  and ). You may want to note these values first, so you can change them back later. I just make sure there's an IPO-curve for them, for example by making a keyframe.
 * 2) Create two new cameras. Reset their position, rotation and size too.
 * 3) Name them Camera.Right and Camera.Left or similar. Set LocX to 1 for Camera.Right and -1 for Camera.Left. (Press  to see data for selected object, in this window you can change name and values.) (Select a camera by clicking  several times on the cameras, until the right one is selected.)
 * 4) Create a new cube (remember to press  to exit edit mode). Reset position, rotation and size. Name it Distance Cube and set these values: LocZ: -30. SizeX: 0.1. SizeY: 0.1. SizeZ: 30.
 * 5) Switch to front view.
 * 6) Select Camera.Left. Then select Camera while holding down  so both are selected. Press  and press  to register Camera as parent. Then press  and select Camera Data. Repeat with right Camera.Right and Distance Cube.

How to use it

 * Never change the cube or the two side-cameras. Only change the center camera. Use that one for positioning, rotation etc.
 * To set the separation: As always, select the center camera. Resize it (with ) so you can see the end of the cube if needed. Point at the end of the cube with the mouse pointer, and press . Move the mouse pointer to the point of the main motive, that is closes to the camera. The end of the cube may not end exactly there, but that doesn't matter.
 * To render (or preview) with one of the side cameras, select it and press.

The cube is visible
Instead of using a cube, I'd rather use something that doesn't render. It could be an "empty", but see below.

The cube is hard to see
It can be hard to see where the cube ends, even in a simple scene. You can select the center camera AND the cube, then it is clearly visible. But you must remember to only select the camera, before you insert a keyframe, so your changes to the cube doesn't get saved.

Distance plane is at infinity
The distance plane is where "zero depth is". When viewing a stereo image, the distance plane is where the medium is. In this rig the distance plane is at infinity, meaning everything is in front of it. While stuff popping out in front of the screen is cooler than stuff being "inside" the screen, it's a lot harder to make it look nice. Specially because with everything in front of the screen, it's easy to get stuff that is just way to close to the viewer. It can get so hard to see that the 3d-effect is completely gone.

A different solution is to make the side cameras point at the end of the cube, or add a plane to the rig, and point at that. But then the cameras are no longer parallel, and that creates distortion.

The compromise solution is to (conceptually) render the images too wide, and then crop the excess from the left side of the left image, and the right side of the right image. Then it will look like it points just like in the previously mentioned solution, but without the distortion.

But this give a lot of problems. First, I'd like to do this a smarter way, instead of just following the path describe above. But I don't think that's possible in Blender. (I think povray can actually do this.) So I need to render the image too wide. But if I increase width in output, it actually renders the same width of the motive, but decreases height. Then I need to do some weird math to get the right FOV, and I don't know half the formulas. Cropping must be done outside Blender, and the rest of "the production line" is hard to get back into Blender if wanted.

I guess a couple of planes in the rig close to the cameras could simulate the cropping, but that is of limited value. To make an adjustable distance plane with them seems quite hard to me, it would need some scripting I guess.

Stereo viewing with the rig
This is where it gets exciting, now you are actually getting something to look at.

 * 1) Create a new screen, you could call it Stereo View.
 * 2) The screen should have one big area from side to side.
 * 3) Set the area to 3D View
 * 4) Unlock it (The Locks layers and used Camera to Scene-lock)
 * 5) Select Camera.Right and press
 * 6) Split the area in half so there is two parts next to each other
 * 7) In the right area, select Camera.Left and press
 * 8) Adjust zoom in both areas so the frame that shows what is rendered is completely visible, but fill as much as possible. If you can't make them same size, the two areas are not same size.
 * 9) Use cross-view method to see the 3d-effect. Look at the left area with the right eye and right area with the left eye. (It's a skill you need to learn and practice.)
 * 10) Press  to see your scene animated in stereo.

If you cannot see these, there is a lot of help with viewing them on the web. Use a search engine to find them.

Anaglyph
Create two render layers in the Render Layers tab.

Then go the Node Editor and click on the button with a human face. Click on Uses nodes and remove the created items by selecting the items and clicking on. Now, using the Add menu, you need to do this diagram: Once done, return to the Buttons window and select the button Do Composite on the Anim tab: Then click on the button Render on the Render tab: You should see your objects as an anaglyph:


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Talk:Suzuki UC125

Hi

I notice that is the manual it says that the gear box oil is only for inspection.

Why so many garage houses change that oil every 4000km? If in the manual says only to check?

Also in the owner manual there is no gear oil change instructions. It only says that it will use 10w40 oil.

What do you advice?

Thanks

Pedro Antunes

pga@oninet.pt

=
=================================================

Response from Warren

Replace the oil every 4000 km, To test the level put the bike on the centre stand and remove the dipstick clean it and insert it (not sure if to be screwed in or not) and the level should be 1/2 to full. There is a bolt on the bottom to drain oil, also the oil filter and the filler hole (but you will need a funnel to get at it with an oil container)

Use the oil that is recommended in the manual. Special motorcycle oil is not needed as it does not have a wet clutch like normal bikes but a scooter CVT transmission.

title: Talk:Suzuki UC125


text: Category:Book:Kinematics

title: Category:Book:Kinematics


text:
Using GNOME/Desktop Background

Desktop backgrounds, or wallpapers, are images that appear on the background of the GNOME desktop. One can select any image or colour to appear as the desktop background.

To alter the desktop background, open the Desktop Background Preferences dialog, by right-clicking on a space on an empty space on the desktop, and selecting Change desktop background from the menu that appears. The Desktop Background Preferences dialog will then appear. The dialog contains a list of default backgrounds, or backgrounds that have been used before.

To select a new image as the desktop background, click on the Add Wallpaper button. A file dialog will appear, and finding and selecting an image from your computer, and then pressing Open will add an entry to the list on the dialog, which can be selected to change the desktop background. Alternatively, one can drag and drop an image from the desktop or the file manager, onto the list, to add an entry.

Desktop background images can appear in the centre of the screen, fill the screen, be scaled fit the screen, or tile to fill the screen. To change how the desktop background behaves, one can use the drop-down menu labelled Style, which appears underneath the list of desktop backgrounds.

To select a plain colour, with no image, as the background, scroll to the top of the list of backgrounds, on the Desktop Background Preferences dialog, to find the entry labelled No Wallpaper. Select this entry by clicking on it. One can then use the colour palette button, which is the coloured block underneath the Desktop colours heading on the dialog, to change the background colour. Clicking the colour button will open a colour selection dialog, and adjusting the colour wheel will change the selected colour. Selecting OK will select that colour.

Changes made in the desktop background dialog will be applied instantly, so there is no need to press a button to save the changes.

title: Using GNOME/Desktop Background


text:
Using GNOME/Theme

Themes are files that alter various aspects of GNOME's appearance. Themes can alter the icons that are used throughout GNOME, the appearance of buttons, windows, scrollbars, and so on (collectively called widgets) and can alter the appearance of window wrappings, which consist of the titlebar and border of windows.

To change which theme GNOME uses, one may have to download a theme from the Internet. Gnome Look has a large collection of themes to choose from. If one chooses to browse Gnome Look, the categories to look under are Gtk 2.x, which are widget themes, Metacity, which are window wrapping themes, and Icon themes. One may already have some alternate themes installed on the system.

To change the theme, or install a new one, one must access the Theme Preferences dialog. This can be accessed from the main menu, by going through Main Menu -> System -> Preferences -> Themes.

To install a new theme, one may click on the Install Theme button on this dialog, and find the appropriate theme file. Alternatively one may drag and drop the file from the desktop or file manager, onto the list in the dialog, and this will install the theme.

To change the theme used, one may select from the list visible on the themes dialog. This list contains whole themes, which change the widgets, icons and window wrappings all at the same time. To select widget, icon and window themes individually, one may select a theme from the list, and click on the button labelled Theme Details. A dialog will appear, with tabs respective to changing the widget, icon and window themes that GNOME uses.

Changes made in the themes dialog will be applied instantly, so there is no need to press a button to save the changes.

title: Using GNOME/Theme


text:
A-level Applied Science/Colour Chemistry

About this Unit
From the AQA Specification:

 You will need to produce a portfolio of evidence detailing the extraction and application of a natural (plant) dye and the preparation and application of a synthetic dye. You should also include evidence detailing the use of organic pigments in an oil-based paint.

Comment: Although most natural dyes are plant dyes, some are derived from animals or minerals. This is of little consequence to the work, however.

The pigments in oil-based paints are usually inorganic. I have assumed that inorganic pigments for paints are valid. AQA do not give any organic pigments as examples; they suggest hydrated iron (III) oxide, zinc potassium chromate (VI), chromium (III) oxide or iron (III) hexacyanoferrate (II) (Prussian Blue).

How you will be assessed
This unit is assessed through the work you complete for your portfolio.

The marking criteria are found in the AQA specification.


text:
A-level Applied Science/Colour Chemistry/Dyes

Dyes are soluble, coloured compounds.

Pigments are insoluble - see Dyes and pigments.

Chromogens are substances which are readily converted into dyes or pigments.

Experiments
Onion skin dye.

Basic dye
Basic dyes are water-soluble cationic dyes that are mainly applied to acrylic fibres, but find some use for wool and silk. With cellulosic fibres an anionic tannic acid mordant is required. Usually ethanoic ('acetic') acid is added to the dyebath to help the uptake of the dye onto the fibre. Basic dyes are also used in the colouration of paper.

The first synthetic dyes, such as mauveine (developed in 1856), are basic. They have a wide colour range, but a reputation for poor light fastness. Modern basic dyes are light fast, and if water can be excluded from the chemical structures the lightfastness is further increased. They are fairly fast to washing except on acrylics; however, the newer basic dyes are very fast on acrylics. They contain a =NH2+ or a -NH3+ group, giving them a charge in solution of +1.

Vat dye
Vat dyes are an ancient class of dyes, based on the natural dye, indigo, which is now produced synthetically. Modern vat dyes (1901) include anthraquinone derivatives, but indigo remains the most important vat dye. They are useful mainly for cotton; but also for wool and other fibres.

The process "vat dyeing" refers to dyeing in a bucket or vat. It can be performed whenever a solid, even shade over the entire garment is desired. Almost any dye can be used, including fiber reactive dyes, direct dyes, and acid dyes. One alternative to vat dyeing is direct dye application, such as the process used for tie dyeing. "Vat dyes" are a special class of dyes that work with a special chemistry. Note that not all vat dyeing is done with vat dyes!

About Vat Dyes

Most vat dyes are less suitable than, say, fibre reactive dyes, for the home dyers, as they are difficult to work with; they require a reducing agent to solubilise them. The dye is soluble only in its reduced (oxygen-free) form. The fibre is immersed repeatedly in this oxygen-free dyebath, then exposed to the air, whereupon the water-soluble reduced form changes colour as oxygen turns it to the water-insoluble, oxidised form. Indigo is an example of this dye class; it changes from yellow, in the dyebath, to green and then blue as the air hits it.

Instructions for dyeing with vat dyes

PRO Chemical & Dye, which sells some vat dyes, provides instructions online for Immersion Dyeing using PRO Vat Dyes. The process requires the use of lye (sodium hydroxide), which must be used with due care, including the use of safety goggles.

Indigo is subject to major crocking (rubbing off of the dye onto other items) unless it is applied carefully. This means use a weaker dyebath, and dipping many times, rather than a single strong dipping.

Light-oxidised Vat Dyes

Ink-o-dye is a type of vat dye which uses light rather than oxygen to 'fix' the dye, with an inspirationally wide variety of possible effects. These dyes, which are chemically similar to vat dyes, Inkodyes are developed by light instead of being applied in an oxygen-free bath and being developed in the fabric by exposure to oxygen. Inkodyes are true dyes, not fabric paints. (A dye actually itself attaches to the fabric; fabric paint includes a glue-like binder, which imparts a stiffer feeling to the fabric.) The process is more difficult than the process of tie-dyeing with fiber reactive dyes. One retail source of Inkodye is Dharma Trading Company.

Further Reading

Imagery on Fabric by Jean Ray Laury

The Chemistry of Vat Dyes by Dianne Epps

Acid dye
Acid dyes (developed in 1862) are water-soluble anionic dyes that are applied to fibres such as silk, wool, nylon and modified acrylic fibers using neutral to acid dyebaths. Attachment to the fibre is attributed, at least partly, to salt formation between anionic groups in the dyes and cationic groups in the fibre.

Acid dyes are have good fastness if the appropariate dye is chosen; but in general they are not substantive to cellulosic fibres. They have a good colour range.

Chemically they are carboxylic or sulphonic acid salts used in an acid dye bath. In the home or art studio, the acid used in the dyebath is often vinegar ('acetic' or ethanoic acid) or citric acid. The dye molecule forms an anion with a charge of -1 to -4, occasionally more.

In textiles, acid dyes are effective on protein fibers, i.e. animal hair fibres like wool, alpaca, mohair and silk. They are effective in dyeing the synthetic fibre nylon but of minimal interest in dyeing any other synthetic fibres.

Acid dyes are generally divided into three classes which depend on fastness requirements, level dyeing properties and economy. The classes overlap and generally depend on type of fibre to be coloured and also the process used.

Acid dyes are thought to fix to fibres by hydrogen bonding. They are normally sold as the sodium salt therefore they are in solution anionic. Animal protein fibres and Nylon fibres contain many cationic sites therefore there is an attraction of anionic dye molecule to a cationic site on the fibre. The strength (fastness) of this bond is related to the desire/chemistry of the dye to remain dissolved in water over fixation to the fiber.

Structures
The chemistry of acid dyes is quite complex. Dyes are normally very large aromatic molecules consisting of many linked rings. Acid dyes usually have a sulphonyl or amino group on the molecule making them soluble in water. Water is the medium in which dyeing takes place. Most acid dyes are related in basic structure to the following:

Anthraquinone type:

Many acid dyes are synthesised from chemical intermediates which form anthraquinone-like structures as their final state. Many blue dyes have this structure as their basic shape. The structure predominates in the levelling class of acid dye.

Azo dyes:

Although Azo dyes are a separate class of dyestuff mainly used in the dyeing of cotton (cellulose) fibres many acid dyes have a similar structure, most are red in colour.

Triaryl type:

Triaryl acid dyes predominate in the milling class of dye.

Classes of acid dyes
Equalising/levelling acid dyes:

Highest level dyeing properties. Quite combinable in trichromatic shades. Relatively small molecule therefore high migration before fixation. Low wet fastness therefore normally not suited for clothing.

Milling acid dyes:

Medium to high wet fastness. Some milling dyes have poor light fastness in pale shades. Generally not combinable - used as self shades only.

Metal complex acid dyes:

More recent chemistry combined transition metals with dye precursors to produce metal complex acid dyes with the highest light fastness and wet fastness. These dyes are also very economical. They produce, however, duller shades.

Health and safety
Any dyes including acid dyes have the ability to induce sensitisation in humans due to their complex molecular structure and the way in which they are metabolised in the body. This is extremely rare nowadays as we have a much greater understanding through experience and knowledge of dyestuffs themselves. Some acid dyes are used to colour food. We wear fabrics every day exposing our skin to dyes.

The greatest risk of disease or injury due to dyes is by ingestion or exposure to dye dust. These scenarios are normally confined to textile workers. Whereby the dye itself is normally non toxic, the molecules are metabolised (usually in the liver) where they may be broken back down to the original intermediates used in manufacture. Thus many intermediate chemicals used in dye manufacture have been identified as toxic and their use restricted. There is a growing trend among governments to ban the importation of dyes synthesised from restricted intermediates. For example: the dye CI Acid red 128 is banned in Europe as it was found to metabolise in the body back to ortho-toluidine, one of its chemical intermediates. Many intermediates used in dye manufacture such as o-toluidine, benzidine etc. were found to be carcinogenic. All the major chemical companies have now ceased to market these dyes. Some, however, are still produced but they are found to be totally safe when on the fiber in its final state. The use of these dyes is declining rapidly as cheap and safer alternatives are now easily available.

The incident concerning the dye Sudan 1 is an example of a suspected toxic dye finding its way into the food chain. Such incidents are extremely rare.

Fibre reactive dye
Fibre reactive dyes utilise a chromophore containing a substituent that is capable, when activated, of directly reacting with the fibre substrate. The covalent bonds that attach reactive dyes to the fibres' amine or hydroxyl groups make them among the most permanent of dyes.

Reactive dyes first appeared commercially in 1956, after their invention in 1954 by Rattee and Stephens at the ICI Dyestuffs Division site in Blackley, Manchester, UK. The dyes contain a reactive group, either a halo-heterocycle or an activated double bond, that, when applied to a fibre in a weakly alkaline dye bath, forms a chemical bond with a hydroxyl group on the cellulosic fibre.

Trichlorotriazine is a common reactive group:

Its three chlorine atoms can readily form HCl with a hydrogen from -OH or -NH2, leaving the O or N attached to the triazine ring in place of the Cl.

"Cold" reactive dyes, such as Procion MX, Cibacron F, and Drimarene K, are very easy to use because the dye can be applied at room temperature. Reactive dye is by far the best choice for dyeing cotton and other cellulose fibres at home or in the art studio. Reactive dyeing is now the most important method for the colouration of cellulose fibres. Reactive dyes can also be applied on wool and nylon, in the latter case they are applied under weakly acidic conditions.

Reactive dyes are available in a good range of colours.

For more info Fundamental Chemistry of reactive dyes

Other reactive dyes:
 * Carbene dyes

Direct dye
Direct or substantive dye molecules (developed 1884) are attracted by intermolecular forces to the textile. The amount of this attraction is known as "substantivity": the higher the substantivity the greater the attraction of the dye for the fibre. They are easy to apply (‘direct’ means ‘without mordant’) and come in a wide range of colours.

Direct dyeing is normally carried out in a neutral or slightly alkaline dyebath, at or near boiling point, with the addition of either sodium chloride (NaCl) or sodium sulphate (Na2SO4). Direct dyes are used mainly on cotton and paper; but also with leather, wool, silk and nylon. Some are used as pH indicators and as biological stains.

Direct dyes are fairly fast to washing, and this can be improved by after-treament. Some have high light fastness. Chemically, the dyes contain the sulphonate group, essential for water-solubility. The more groups, the more water-soluble. Usually 2-4, occasionally 1 or 5 groups. The chromophore is usually azo type.

Disperse dye
Disperse dyes were originally developed (1923) for the dyeing of cellulose acetate, but can also be used to dye nylon, triacetate and polyester fibres. They are fast if the correct dye is selected for the fibre. Acrylics can be dyed with disperse dyes, but are only moderately fast and will not take intense dyeing.

Chemically, disperse dyes are water-insoluble azo and anthraquinone dyes. The dyes are finely ground in the presence of a dispersing agent and then sold as a paste, or spray-dried and sold as a powder.

The dyes are applied as dispersions (emulsions). In some cases, a dyeing temperature of 130 °C is required, and a pressurised dyebath is used. The very fine particle size gives a large surface area that aids dissolution to allow uptake by the fibre. The dyeing rate can be significantly influenced by the choice of dispersing agent used during the grinding.

Disperse dyes are available in a wide range of colours.

Azo dye
Azo dyeing is a technique in which an insoluble azo dye is produced directly onto or within the fibre. This is achieved by treating a fibre with both diazoic and coupling components. With suitable adjustment of dyebath conditions the two components react to produce the required insoluble azo dye. This technique of dyeing is unique, in that the final colour is controlled by the choice of the diazoic and coupling components.

Azo compounds generally have a molecular formula of the form R-N=N-R', in which R and R' can be either aromatic or aliphatic. The N=N group is called an azo or diimide functional group. The aromatic groups help to stabilise the N=N group by making it part of an extended delocalised system. This also has the effect of making many azo compounds coloured, as delocalised or conjugated systems often absorb visible frequencies of light.

The name azo comes from azote, an old name of nitrogen that originates in French and is derived from the Greek a (not) + zoe (to live). Aromatic azo compounds (R = R' = aromatic) are usually stable and have vivid colors such as red, orange, and yellow. Therefore, they are used as dyes, which are called azo dyes. Some azo compounds, e.g. Methyl orange, can also be used as acid-base indicators, due to their ability to function as weak acids, and the different colours of the acid and salt forms. Azobenzene is another typical aromatic azo compound. Their colour originates from absorbance in the visible region of the spectrum due to the delocalisation of electrons in the benzene and azo groups forming a conjugated system, whereby the N=N group is the chromophore.

Aliphatic azo compounds (R and/or R' = aliphatic) are rather unstable. At an elevated temperature or by irradiation, two carbon-nitrogen (R-N) bonds are cleaved simultaneously with the loss of nitrogen gas to generate carbon-centered radicals.

Aromatic azo compounds can be synthesized by using an azocoupling reaction, that is, an electrophilic substitution reaction on aromatic rings with diazonium salts. Diazonium salts decompose at temperatures warmer than about 5 degrees Celsius, so the reaction must take place in solution under freezing conditions:

Anthraquinones
Anthraquinone (9,10-dioxoanthracene) is an aromatic organic compound. It is a derivative of anthracene. It has the appearance of yellow or light grey to grey-green solid crystalline powder.

Its other names are 9,10-anthracenedione, anthradione, 9,10-anthrachinon, anthracene-9,10-quinone, 9,10-dihydro-9,10-dioxoanthracene, and trade names Hoelite, Morkit, Corbit, and others.

Natural occurrences
Anthraquinone naturally occurs in some plants (e.g. aloe, senna, rhubarb, and Cascara buckthorn), fungi, lichens, and insects, where it serves as a basic skeleton for their pigments. Natural anthraquinone derivates tend to have laxative effects.

Industrial applications
Anthraquinone is used in production of dyes, such as alizarin. Many natural pigments are derivatives of anthraquinone.

Sulphonic dye
Direct dyes and acid dyes contain sodium sulphonate groups.

Triaryl dye

Dyes having structures related to triphenylmethane are known as triaryl ('aryl' refers to the 'phenyl' (benzene) rings).

There are many yellow and green dyes commercially applied to fibres that are related to triphenylmethane.

Cationic dye
See Basic dye

Anionic dye
See Acid dye

Polyphenols
Many coloured plant compounds are classed as polyphenols as they contain multiple benzene rings with multiple -OH groups attached. (A benzene ring with a single -OH group is called phenol.)

The main active dye in turmeric is the polyphenol curcumin:

Demethoxycurcumin and bis-Demethoxycurcumin are also present, in smaller quantities. They lack one or both methyl groups present in curcumin.

Flavonoids are polyphenols based on the flavone structure:

The yellow dye in onion skins is made a of mixture of flavonoids: quercetin, kaempferol and quercetin-3-glucoside.

Halochromic dyes and Indicators
A halochromic material is a material which changes colour when pH changes occur. The term ‘chromic’ is defined as materials that can change colour reversibly with the presence of a factor. In this case, the factor is pH. pH indicators have this property.

Halochromic substances are suited for use in environments where pH changes occur frequently, or places where changes in pH are extreme. Halochromic substances detect alterations in the acidity of substances, such as detection of corrosion in metals.

Curcumin is a halochromic dye - at high pH its -OH groups become ionised to -O- and its colour changes from red to yellow.

Redox indicators are not halochromic. These compounds change colour according to whether they are oxidised or reduced.

Indigo (left) is blue and insoluble when oxidised, but is colourless and soluble when reduced (right). In the reduced state it is known as leucoindigo.

Methylene blue is another example.


text:
A-level Applied Science/Colour Chemistry/Fibres

Fibre or fiber is a class of materials that are continuous filaments or are in discrete elongated pieces, similar to lengths of thread. Fibers are of great importance in the biology of both plants and animals, for holding tissues together. Human uses for fibres are diverse. They can be spun into filaments, thread, string or rope. They can be used as a component of composite materials. They can also be matted into sheets to make products such as paper or felt. Fibres are often used in the manufacture of other materials.

Fibres used by man come from a wide variety of sources.
 * Natural fibres include those produced by plants, animals, and geological processes. They can be classified according to their origin:
 * Vegetable fibres are generally based on arrangements of cellulose, often with lignin: examples include cotton, linen, hemp, jute, flax, ramie and sisal. Plant fibers serve in the manufacture of paper and cloth.
 * Animal fibres consist largely of particular proteins. Instances are silk, sinew, catgut and hair (including wool).
 * Mineral fibres comprise asbestos, the only naturally occurring mineral fibre.
 * Man-made fibres may come from natural raw materials or from synthetic chemicals.
 * Many types of fibre are manufactured from natural cellulose, including rayon, modal, and the more recently developed Lyocell. Fibreglass and optical fibre, which are made from purified natural quartz, are also man-made fibers that come from natural raw materials.
 * Synthetic fibres are a subset of man-made fibres, which are based on synthetic chemicals (often from petrochemical sources) rather than arising from natural materials by a purely physical process. Such fibres are quite often made from nylon, polyester, or acrylic polymers, although pure polyacrylonitrile fibres are used to make carbon fibre.  More exotic  fibres  have strong bonding between polymer chains (e.g. aramids), or extremely long chains (e.g. Dyneema or Spectra). Elastomers can even be used, e.g. spandex.


text:
Talk:Intermediate Algebra/Logarithms

I believe that we should add at this page the definition a^x=z <=> x= log_a(z) The ln (logarith with base e) should also be covered.

 * Oh, we need even more stuff than this. For one thing, logarithms aren't simply rearrangements of other equations - they are a problem-solving method involving that, but they have their own properties which need to be proven. One does not fully understand a logarithm without proofs.

 * For that matter, there is a property missing from the page: log_a(b) / log_a(c) = log_c(b). It's called "change of base". Have a look at the full article on Wikipedia: Logarithm --Deriamis 22:24, 25 July 2006 (UTC)

 * I added the change of base rule, there's also a couple other properties of logs (like a special case of the change of base rule, log_b(a) = 1/log_a(b)) that may or may not be important enough to put in there. I'm not sure, do you think I should keep the example in there? Mattb112885 02:20, 29 July 2006 (UTC)

title: Talk:Intermediate Algebra/Logarithms


text:
Talk:Gujarati

Writing lessons
I would really like to see lessons teaching how to read and write Gujarati step-by-step, rather than just an overview of all letters. It's hard to learn from it. The lack of examples is another problem, but even if there were examples afterwards the learning situation would be far from perfect because the student would still have to memorise all letters at once in order to be able to begin practising.

What I have found really useful when learning non-Latin alphabets is a "divide and conquer" method that introduces few letters at a time and offers example words for practise immediately after each letter / each set of letters. What's even better is if those example words are understandable without prior knowledge of the language, that is, international words. For example: names of countries, cities or famous people (if their name isn't significantly different in Gujarati than in English), common personal names, Gujarati words that have entered English, English words that are used in Gujarati, words that both Gujarati and English have derived from Greek or Latin... The advantage of using these words is that students will be able to quickly see their own progress and the whole learning process becomes as fascinating as solving a puzzle. See the "Read Write and Pronounce Greek" lessons in the Modern Greek Wikibook for an example, or this external page on Cyrillic.

If you'd like to try this approach for teaching the Gujarati script, I'd be glad to help you, even though I don't know how to read it yet (I have learned a variety of other alphabets though and I'd like to learn how to write Gujarati too). Just create a big list of suitable words on a planning page like Modern Greek/Writing lessons plan, answer me here and I'll try to find an optimal order for letters.

Thanks for your efforts to teach a language that is hard to find in European schools!

Junesun 16:34, 11 July 2006 (UTC)

P.S.: If there's somebody generally unsure about how to create good language lessons, I really recommend reading the following two pages about it: Authoring Foreign Language Textbooks and Authoring Foreign Language Textbooks/Bite-sized language lessons.

A few considerations
We need a convention for romanizing that we can stick to for this book, since there are so many different varieties in use for gujarati. One that we use here would preferably be easily enterable in standard English characters -- that puts accent marks out.

Since there's not too much activity or content on here yet, i'm going to go ahead and start using as follows. If you have better suggestions, please speak up, because this system looks really weird and bad; but I think the accuracy is needed:

 * Retroflex consonants are represented by placing a ' AFTER the consonant. Ex: taarũ (your), mot'ũ (big)
 * Long vowels are written by repeating the vowel. Ex: maarii maa (my mother), mane/tane (to me/to you)
 * Nasalized vowels are represented by placing a ' AFTER the vowel. Ex: taarũ (your), kasu (something)
 * Nasalized vowels are represented by placing a ~ above the vowel. Ex: taarũ (your), kashũ (something)
 * Aspiration is represented by an h after the consonant. NOTE: Do not use h's when not necessary! DO NOT WRITE thame or thũ or thamaarũ, INSTEAD WRITE tame, tũ, tamaarũ.
 * Exception: ch is written ch ચ (unaspirated) and chh છ (aspirated). Ex: e maarũ chhe.

Also, I'm not a native Gujarati, so please correct me all the time. I might transgress these rules here simply because I don't actually know which way a word is supposed to be pronounced.

--Auk (talk) 08:27, 13 December 2008 (UTC)

title: Talk:Gujarati


text:
Talk:Urdu/Alphabet

Teaching Urdu
I would really like to see lessons teaching how to read and write Urdu step-by-step. It's hard to learn from an overview of letters. Lack of examples is another problem, but even if there were examples afterwards the learning situation would be far from perfect because the student would still have to memorise all letters at once in order to be able to begin practising.

What I have found really useful when learning non-Latin alphabets is a "divide and conquer" method that introduces few letters at a time and offers example words for practise immediately after each letter / each set of letters. What's even better is if those example words are understandable without prior knowledge of the language, that is, international words. For example: names of countries, cities or famous people (if their name isn't significantly different in Marathi than in English), common personal names, Urdu words that have entered English, English words that are used in Urdu, words that both Urdu and English have derived from Greek or Latin... The advantage of using these words is that students will be able to quickly see their own progress and the whole learning process becomes as fascinating as solving a puzzle. See the "Read Write and Pronounce Greek" lessons in the Modern Greek Wikibook for an example, or this external page on Cyrillic.

If you'd like to try this approach for teaching how to write Urdu, I'd be glad to help you, even though I don't know it yet (I can read Arabic ok though). Just create a big list of suitable words on a planning page like Modern Greek/Writing lessons plan, answer me here and I'll try to find an optimal order for letters.

Thanks for your efforts to teach a language that is hard to find in European schools!

Junesun 16:42, 11 July 2006 (UTC)

P.S.: If there's somebody generally unsure about how to create good language lessons, I really recommend reading the following two pages about it: Authoring Foreign Language Textbooks and Authoring Foreign Language Textbooks/Bite-sized language lessons.

title: Talk:Urdu/Alphabet


text:
Talk:Thai

Teaching the Thai alphabet
I would really like to see lessons teaching how to read and write Thai step-by-step. It's hard to learn from an overview of letters. Lack of examples is another problem, but even if there were examples afterwards the learning situation would be far from perfect because the student would still have to memorise all letters at once in order to be able to begin practising.

What I have found really useful when learning non-Latin alphabets is a "divide and conquer" method that introduces few letters at a time and offers example words for practise immediately after each letter / each set of letters. What's even better is if those example words are understandable without prior knowledge of the language, that is, international words. For example: names of countries, cities or famous people (if their name isn't significantly different in Thai than in English), common personal names, Thai words that have entered English, English words that are used in Thai, words that both Thai and English have derived from Greek or Latin... The advantage of using these words is that students will be able to quickly see their own progress and the whole learning process becomes as fascinating as solving a puzzle. See the "Read Write and Pronounce Greek" lessons in the Modern Greek Wikibook for an example, or this external page on Cyrillic.

If you'd like to try this approach for teaching how to write Thai, I'd be glad to help you, even though I only know a bit of Thai so far. I'd like to learn it though and I can read quite a few other scripts. Just create a big list of suitable words on a planning page like Modern Greek/Writing lessons plan, answer me here and I'll try to find an optimal order for letters.

Thanks for your efforts to teach a language that is hard to find in European schools!

Junesun 17:27, 11 July 2006 (UTC)

P.S.: If there's somebody generally unsure about how to create good language lessons, I really recommend reading the following two pages about it: Authoring Foreign Language Textbooks and Authoring Foreign Language Textbooks/Bite-sized language lessons.

Additions
I've added some tables and brief descriptions of various features of the language. Hopefully we'll be able to expand these further into real lessons. Stevey7788 (talk) 07:48, 28 October 2010 (UTC)

"Native range of Thai and closely related Tai languages"
This figure title is misleading, as Lao and Kam Mueang are not "closely related Tai languages" https://en.wikipedia.org/wiki/Northern_Thai_language 171.4.251.25 (discuss) 07:48, 28 September 2022 (UTC)

title: Talk:Thai


text:
Java Programming/API/java.lang.Class

The  is defined in the  package.

There is a  object for each class in your program. The object is loaded from .class file once when the object of that type is referenced from the first time. After that it stays in memory. The object is responsible to creat all the object instances that belong to that class.

Every array also belongs to a class that is reflected as a object that is shared by all arrays with the same element type and number of dimensions. The primitive types (,, , , , , , and ), and the keyword are also represented as  objects. Class has no public constructor. Instead Class objects are constructed automatically by the Java Virtual Machine as classes are loaded

Since JDK 1.5 the class java.lang.Class is generic. It's an interesting example of using genericity for something other than a container/collection class.

For example, the type of String.class is Class, and the type of Serializable.class is Class. This can be used to improve the type safety of your reflection code.

title: Java Programming/API/java.lang.Class


text:
Cookbook:Chai Tea

Chai tea, also known simply as "chai" (pronounced chaī), is a kind of sweetened black tea beverage. It is most popular in Southern Asia, though in recent years it has gained attention in North America and England, where the terms "chai" and "chai tea" usually refer to masala chai (spiced tea). In America, one can often find chai mixes—the chai equivalent of instant coffee. These mixes, though delicious, usually lack the taste that can only be found in home-brewed chai. Chai is also featured in many coffee shops like Starbucks.

Many chai drinkers attest that chai creates a warm, homey, passive feeling in the drinker. It has a subtle flavor and is meant to be gulped down and dipped into with a tea rusk. It has a nice beige/caramel color, and has a little more thickness to it like what coffee has.

History
Chai can be traced back to a Hindu healing practice known as "ayurveda"; a mixture not unlike today's chai was used to treat physical ailments.

Etymology
Chai is the Hindi word (Hindi: चाय) for tea, from the Persian ćāy (چای) and ultimately the Mandarin chá (茶). In English, the term is used to refer to what is more properly known as masala chai (Hindi (मसाला चाय [masālā chaiy], "spiced tea"). Words for tea either derive from the Mandarin and Cantonese cha in Guangzhou or the Min tê in Fujian. Cha derivatives are the word for tea in Arabic, Persian, Kurdish, Turkish, Urdu, Russian (чай), and Czechian (čaj). Te derivatives are the word for tea in English, Dutch, Hebrew, Tamil, Polish, and Swedish.

Variations
In South East Asia, Chai is a tradition- and involves elaborate Tea ceremonies and is a form of meditation itself.

In India, the chai drinking habit is very pronounced in the northern part of the country and in the southernmost tip - in Kerala. The way chai is brewed also varies widely. In the mountains of North East India, Chai is brewed without milk or even without sugar (Salt is used as a substitute) or locally available Yak milk, Yak butter or Clarified Butter (Ghee) is used.

The flavor of chai is further enhanced with the addition of multiple fresh locally available ingredients including Lemon Grass, Ginger, Saffron, Fennel (Sounf), cardamom (Elaichi), Cinnamon, Camomille.,

There are different methods of making chai in different regions. For example, Indian chai has a spicy taste, while Pakistani chai has a lighter, creamier touch.

The following recipes are all variations of chai:

Ingredients
Generally speaking, chai preparations usually contain black tea, milk, spices, and a sweetener.

Tea

 * Black tea - the most commonly used type for chai in the Hindustan is crush-tear-curl black tea, easily found at Southeast Asian grocers. This tea looks like pellets and is able to stand up to the boiling on a stove-top that creates the chai masala infusion.
 * Earl Grey
 * Darjeeling Tea: Hard to find, but often considered on of the finest black teas available.

Milk
Steamed milk is best to use for chai, but it takes time and skill to prepare. Low-fat milk, whole milk, creamer, or dried milk can all be used.

Sweeteners
Honey is often used as chai sweetener, and it has a powerful flavor. For a more Western taste, white sugar or artificial sweeteners may be used.

Additional flavorings
Chai beverages may be flavored in various ways. Some flavorings include:
 * Cloves
 * Cardamom seeds: Very common in chai. They are often de-shelled or ground for preparation in chai, but leaving them in the shell is not unheard of.
 * Cinnamon: Common in westernized chai, especially "winter" or "Christmas" chai. Both Cinnamon stick and cinnamon sugar can be used.
 * Ginger: Common in chai; can be used either whole or in powdered form.
 * Nutmeg
 * Peppercorn: Very common in chai. Can be used either whole or ground.
 * Pumpkin pie spice: Found in "christmas" or "pumpkin pie" chai. Should be used in moderation, as it can be overpowering.
 * Vanilla
 * Cocoa
 * Licorice

title: Cookbook:Chai Tea


text: Category:Book:Koine Greek

title: Category:Book:Koine Greek


text:
A-level Applied Science/Colour Chemistry/Fibres/Cellulose

Cellulose

Cellulose(C6H10O5)n is a long-chain polymeric polysaccharide carbohydrate, of beta-glucose. It forms the primary structural component of green plants. The primary cell wall of green plants is made primarily of cellulose.

History and applications
Cellulose is found in all plant material. It is the most abundant form of living terrestrial biomass.

Cellulose is the major constituent of paper; further processing can be performed to make cellophane]] and rayon, and more recently Modal, a textile derived from beechwood cellulose. Viscose is a very important fibre made out of cellulose and has been used for textiles since the beginning of the 20th century.

Chemistry
Cellulose monomers (β-glucose) are linked together through ß1→4 glycosidic bonds by condensation. This is in contrast to the α 1->4 glycosidic bonds present in other carbohydrates like starch.

Cellulose is a straight chain polymer: unlike starch, no coiling occurs, and the molecule adopts an extended rod-like conformation. In microfibrils, the multiple hydroxyl (OH-) groups on the glucose residues hydrogen bond with each other, holding the chains firmly together and contributing to their high tensile strength. This strength is important in cell walls, where they are meshed into a carbohydrate matrix, helping keep plant cells rigid.

Derivatives
The hydroxyl groups of cellulose can be partially or fully reacted with various chemicals to provide derivates with useful properties. Cellulose esters and cellulose ethers are the most important commercial materials. In principle, though not always in current industrial practice, cellulosic polymers are renewable resources.

Among the esters are cellulose acetate and triacetate, which are film- and fibre-forming materials that find a variety of uses.

Cotton

Cotton is a soft fibre that grows around the seeds of the cotton plant (Gossypium spp.), a shrub native to the tropical and subtropical regions. The fibre is most often spun into thread and used to make a soft, breathable textile, which is the most widely used natural-fibre cloth in clothing today.

Cotton fibre (once processed to remove seeds and traces of wax, protein, etc.) consists of nearly pure cellulose, a natural polymer. The cellulose is arranged in a way that gives cotton fibres a high degree of strength, durability, and absorbency. Each fibre is made up of twenty to thirty layers of cellulose coiled in a neat series of natural springs. When the cotton boll (seed case) is opened the fibres dry into flat, twisted, ribbon-like shapes and become kinked together and interlocked. This interlocked form is ideal for spinning into a fine yarn.

Uses of cotton
Cotton is used to make a number of textile products. These include terrycloth, used to make highly absorbent bath towels and robes, denim, used to make blue jeans, chambray, popularly used in the manufacture of blue work shirts (from which we get the term "blue-collar"), along with corduroy, seersucker, and cotton twill. Socks, underwear, and most T-shirts are made from cotton. Bed sheets are also often made from cotton. Cotton is also used to make yarn used in crochet and knitting. While many fabrics are made completely of cotton, some materials blend cotton with synthetic or processed fibres such as polyester or rayon. In addition to the textile industry, cotton is used in fishnets, coffee filters, tents and in bookbinding. The first Chinese paper was made of cotton fibre, as is the modern US dollar bill and federal stationery. Fire hoses were once made of cotton.

Mercerisation is a treatment for cotton fabric and thread mostly employed to give cotton a lustrous appearance. The series of processes was devised by John Mercer in the middle of the 19th century.

Mercerised cotton is sometimes referred to in the crafts as pearl or pearle cotton. It is cotton yarn or fabric which has been put through a series of processes, primarily to increase lustre. The added desirable water handling properties gained are a secondary bonus.

Cotton thread (or cotton-covered thread with a polyester core) is treated with sodium hydroxide (caustic soda, NaOH). The thread is given a caustic soda bath that is then neutralised with an acid bath. This treatment increases strength, lustre, affinity to dye and resistance to mildew, and also reduces lint. Long staple fibre lengths respond best to mercerisation.

References and further reading

 * The Thames and Hudson Manual of Dyes and Fabrics, Joyce Storey, 1978

History and uses of cotton

 * Cotton's journey - Educational website
 * Glossary of cotton terms
 * Naturally coloured cotton

Research

 * ACSA International Cotton Institute
 * U.S. Department of Agriculture
 * UNCTAD Information on Cotton

Rayon
Rayon is a manufactured regenerated cellulosic fibre.

History of rayon
Rayon was the first fibre to be manufactured; it is produced from naturally occurring polymers and therefore it is not a synthetic fibre, but a manufactured regenerated cellulosic fibre. The fibre was sold as artificial silk until the name "rayon" was adopted in 1924. In Europe it is known as "viscose".

Major fibre properties of rayon
Rayon is a very versatile fibre and has the same comfort properties as other natural fibres and can imitate the feel and texture of silk, wool, cotton and linen. The fibres are easily dyed in a wide range of colours. Rayon fabrics are soft, smooth, cool, comfortable, and highly absorbent, but do not insulate body heat making them ideal for use in hot and humid climates. The durability and appearance retention of regular rayon are low, especially when wet; also rayon has the lowest elastic recovery of any fibre. However, HWM rayon is much stronger and exhibits higher durability and appearance retention. Recommended care for regular rayon is dry-cleaning only, HWM Rayon can also be machine washed.

Producers of rayon
Trade names are used within the rayon industry to determine the type of rayon used.

Bemberg, for example, is a trade name for cuprammonium rayon that is only produced in Italy due to EPA regulations in the US.

MODAL is a widely used form of rayon produced by Lenzing Fibres Corp. which is based out of northern Austria.

Galaxy, Danufil, and Viloft are rayon brands produced by Kelheim Fibres, a German manufacturer.

Acordis is a major manufacturer of cellulose based fibres and yarns. Production facilities can be found throughout Europe, the U.S. and Brazil.

Visil rayon is a flame retardant form of viscose which has silica built into the content of the fibre during manufacturing.

Uses of rayon
Some major Rayon fibre uses include apparel (e.g. blouses, dresses, jackets, lingerie, linings, suits, ties), furnishings (e.g. bedspreads, blankets, window treatments, upholstery, slipcovers), industrial uses (e.g. medical surgery products, non-woven products, tire cord), and other uses (e.g. feminine hygiene products).

Viscose
Cellulose fibres from wood, cotton or hemp are dissolved in alkali to make a solution called viscose. Viscose used in Europe as the name of the fibre rayon.

Cellophane is a thin, transparent sheet made of processed cellulose. It is made when viscose solution is extruded through a slit into an acid bath to reconvert the viscose into cellulose. A similar process, using a hole instead of a slit (a spinneret), is used to make a fibre called rayon.

Cellophane
See Viscose

Modal
See Rayon

Triacetate
Triacetate also known as 'cellulose triacetate', is manufactured from cellulose and acetate. Triacetate is typically used for the creation of fibres and film base. It is similar chemically to cellulose acetate, with the distinguishing characteristics being that in triacetate, according to the Federal Trade Commission definition, at least "92 percent of the hydroxyl groups are acetylated". During the manufacture of triacetate the cellulose is completely acetylated whereas in regular cellulose acetate or cellulose diacetate, it is only partially acetylated. Triacetate is significantly more heat resistant than cellulose acetate.

Production of triacetate
Triacetate is derived from cellulose by combining cellulose with acetate from acetic acid and acetic anhydride. The cellulose acetate is dissolved in a mixture of dichloromethane and methanol for spinning. As the filaments emerge from a spinneret, the solvent is evaporated in warm air, in a process known as dry spinning, leaving a fibre of almost pure triacetate.

A finishing process called S-Finishing or surface saponification is sometimes applied to acetate and triacetate fabrics using a sodium hydroxide solution. This removes part or all of the acetyl groups from the surface of the fibres leaving them with a cellulose coating. This reduces the tendency for the fibres to acquire static.

Chemistry
CAS number 9012-09-3

Characteristics

 * Shrink resistant
 * Wrinkle resistant
 * Easily washable
 * Generally washable at high temperatures
 * Maintains creases and pleats well

Usage Scenarios
Particularly effective in clothing where crease or pleat rentention is important, such as skirts and dresses

General Care Tips
Always refer to individual garment care labels

 * Ironable up to 200 °C
 * Pleated garments are best hand laundered. Most other garments containing 100% triacetate can be machine washed and dried
 * Articles containing triacetate fibres require very little special care due mainly to the fibre's resistance to high temperatures

Cellulose acetate
Cellulose acetate is the acetate ester of cellulose. Cellulose acetate is used as a film base in photography, and as a component in some adhesives; it is also used as a synthetic fibre.

Acetate Fibre and Triacetate Fibre
Acetate and Triacetate are mistakenly referred to as the same fibre, although they are similar, their chemical compounds differ. Triacetate is known as a generic description or primary acetate containing no hydroxyl group. Acetate fibre is known as modified or secondary acetate having a few hydroxyl groups. Triacetate fibres, although no longer produced in the United States, contain a higher ratio of acetate-to-cellulose than do acetate fibres[1].

Fibre
Cellulose acetate or acetate rayon fibre (1924) is one of the earliest synthetic fibres and is based on cotton or tree pulp cellulose ("biopolymers"). These "cellulosic fibres" have passed their peak as cheap petro-based fibres (nylon and polyester) and have displaced regenerated pulp fibres.

Fibre Properties
Acetate is a very valuable manufactured fibre that is low in cost and has good draping qualities. Properties of acetate have promoted it as the “beauty fibre”[1]. Acetate is used in fabrics such as satins, brocades, and taffetas to accentuate luster, body, drape and beauty.
 * Hand: soft, smooth, dry, crisp, resilient
 * Comfort: breathes, wicks, dries quickly, no static cling
 * Drape: linings move with the body linings conform to the garment
 * Colour: deep brilliant shades with atmospheric dyeing meet colourfastness requirements
 * Luster: light reflection creates a signature appearance
 * Performance: colourfast to perspiration staining, colourfast to dry cleaning, air and vapor permeable
 * Tenacity: weak fibre with breaking tenacity of 1.2 to 1.4 g/d; loses strength when wet
 * Environmentally friendly: made from wood pulp of reforested trees
 * Abrasion: poor resistance
 * Heat retention: poor thermal retention; no allergenic potential (hypoallergenic)
 * Dyeability: (two methods) cross-dying method where yarns of one fibre and those of another fibre are woven into a fabric in a desired pattern; solution-dying method provides excellent colour fastness under the effects of sunlight, perspiration, air contaminants and washing [1,2]

Acetate usually requires dry cleaning.

Production
The Federal Trade Commission definition for acetate fibre is "A manufactured fibre in which the fibre-forming substance is cellulose acetate. Where not less than 92 percent of the hydroxyl groups are acetylated, the term triacetate may be used as a generic description of the fibre."

Acetate is derived from cellulose by deconstructing wood pulp into a purified fluffy white cellulose. The cellulose is then reacted with acetic acid and acetic anhydride in the presence of sulfuric acid. It is then put through a controlled, partial hydrolysis to remove the sulfate and a sufficient number of acetate groups to give the product the desired properties. The anhydroglucose unit is the fundamental repeating structure of cellulose and has three hydroxyl groups which can react to form acetate esters. The most common form of cellulose acetate fibre has an acetate group on approximately two of every three hydroxyls. This cellulose diacetate is known as secondary acetate, or simply as "acetate".

After it is formed, cellulose acetate is dissolved in acetone into a viscose resin for extrusion through spinnerets (which resemble a shower head). As the filaments emerge, the solvent is evaporated in warm air via dry spinning, producing fine cellulose acetate fibres.

First U.S. Commercial Acetate Fibre Production: 1924, Celanese Corporation

Current U.S. Acetate Fibre Producers: Celanese Acetate, Eastman Chemical Company

Production Method

 * 1) Purified cellulose from wood pulp or cotton linters
 * 2) Mixed with glacial acetic acid, acetic anhydride, and a catalyst
 * 3) Aged 20 hours- partial hydrolysis occurs
 * 4) Precipitated as acid-resin flakes
 * 5) Flakes dissolved in acetone
 * 6) Solution is filtered
 * 7) Spinning solution extruded in column of warm air. Solvent recovered
 * 8) Filaments are stretched and wound onto beams, cones, or bobbins ready for use [1]

Trademarks [4]
Trade Names---Manufacturer
 * Celanese (forms produced: flake and tow)--*Celanese Acetate
 * Celstar--*Celanese Acetate
 * Chromspun--*Eastman Chemical Company
 * Estron--*Eastman Chemical Company
 * MicroSafe--*Celanese Acetate

* Voridian Company is an operating division of Eastman Chemical Company

Voridian introduced acetate tow in 1952 and remains a leading manufacturer today. Voridian sells acetate tow under the trademark Estron[5].

Acetate Fibre Characteristics

 * cellulosic and thermoplastic
 * selective absorption and removal of low levels of certain organic chemicals
 * easily bonded with plasticisers, heat, and pressure
 * acetate is soluble in many common solvents (especially acetone and other organic solvents) and can be modified to be soluble in alternative solvents, including water
 * hydrophilic: acetate wets easily, with good liquid transport and excellent absorption; in textile applications, it provides comfort and absorbency, but also loses strength when wet
 * acetate fibres are hypoallergenic
 * high surface area
 * made from a renewable resource: reforested trees.
 * can be composted or incinerated
 * can be dyed, however special dyes and pigments are required since acetate does not accept dyes ordinarily used for cotton and rayon (this also allows cross-dyeing)
 * resistant to mold and mildew
 * easily weakened by strong alkaline solutions and strong oxidizing agents.
 * can usually be wet cleaned or dry cleaned and generally does not shrink

Major industrial acetate fibre uses

 * apparel: linings, blouses, dresses, wedding and party attire, home furnishings, draperies, upholstery and slip covers
 * high absorbency products: nappies, feminine hygiene products, cigarette filters, surgical products, and other filters
 * Ink reservoirs for fibre tip pens, industrial fabrics, holiday [5]

Paper
Paper is a thin, flat material produced by the compression of fibres. The fibres used are usually natural and composed of cellulose. The most common source of these kinds of fibres is wood pulp from pulpwood trees, (largely softwoods) such as spruce. However, other vegetable fibre materials including cotton], hemp, linen, and rice may be used.


text:
Category:Book:Korean

ja:Category:朝鮮語

title: Category:Book:Korean