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Latin/Lesson 7-The Gerund and Participles

= Participles =

Participles are verbs which function grammatically like adjectives. English, aided by auxiliary participles, is able have participle phrases in many tenses. Latin has participles that do not have auxiliary supplementary participles. This limits the usage of the participle in Latin, according to some wiki-scholars of Classical Studies.

Present Active Participles
Present participles are formed by adding -ns to the stem of the verb.

Present Participles are declined like 3rd declension adjectives. In cases besides the nominative, the -s becomes -t.

Examples:

1. ferens, ferentis 2. capiens, capientis 3. ens, entis

Exercises
Form the Present Participle and translate of the following Latin verbs:

 * meto, messui, messum, ere
 * metuo, metum, ui, ere
 * milito, avi, atum, are
 * postulo, avi, atum, are
 * sulco, avi, sulcum, are
 * iacio, ieci, iactum, ere

Uses
The examples will show participles of the verb amo, amare, amavi, amatum (to love).

 * present active: base + 'ns.' This forms a two-termination 3rd declension adjective. In the case of amare, the participle is amans, amantis (loving).
 * perfect passive: fourth principle part, with appropriate first or second declension endings: amatus, -a, -um.
 * future active: fourth principle part, minus 'm', add 'rus, -a, -um' This forms a 1st-2nd declension adjective: amaturus, -a, -um (about to love).

In deponent verbs, the perfect passive participle is formed in the same way as in regular verbs. However, since the nature of the deponent verb is passive in form and active in meaning, the participle is translated actively.

Remember that participles are adjectives, and therefore must be declined to agree with the noun which they modify in case, number and gender.

Gerund
The gerund is a verbal noun which is used to refer to the action of a verb. For example: ars scribendi = the art of writing. The gerund is declined as a second declension neuter noun. It is formed by taking the present stem and adding -ndum.

Meanings of the gerund

 * Genitive: ars legendi - The art of reading / to read
 * Accusative: ad puniendum - to punish, for punishing
 * Ablative: saepe canendo - through frequently singing; in legendo: while reading
 * Genitive with causa: puniendi causa - in order to punish

Gerundive
The gerundive is a 1st/2nd declension adjective formed the same way as the gerund, and its function overlaps somewhat with the gerund, but otherwise differs. The literal translation of the gerundive is with "to be", eg. defendendus, -a, -um = "to be defended".

 * Accusative: ad ludos fruendos - to the games to be enjoyed - to enjoy the games (Note that if this were a gerund construction, it would be ad ludis fruendum since fruor, -i takes the ablative case. In the gerundive construction, both noun and gerundive are governed by the preposition ad)
 * Gerundive of obligation, which is constructed with the verb 'est' or 'sunt', according to the subject's number: Carthago delenda est - Carthage is to be destroyed - Carthage must be destroyed. Note that if there is an object (eg. Carthage is to be destroyed by us), it goes into the dative case (eg. Carthago delenda nobis est).

=Exercises=

1. Convert the following subjunctive purpose clauses into gerund or gerundive clauses with the same meaning. For example: militabat ut patriam defenderet → militabat ad patriam defendendum or militabat patriam defendendi causa or militabat ad patriam defendendam. Try to use each construction twice.
 * casam exit ut patrem adiuvet
 * mater in casam rediit ut cenam pararet
 * hostes vincebant ergo scutum abieci (I threw away my shield) ut celerius fugerem
 * in silvas currimus ut nos celemus
 * hostes in silvas ineunt ut nos invenirent
 * Brutus Iulium Caesarem occidit ut Romam liberaret

2. Translate into Latin. For example: I must see the temple -> templum mihi videndum est
 * We must build a large city.
 * Julius Caesar must lead an army into Greece.
 * Scipio (Scipio, -ionis) must defeat Hannibal.


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Talk:US History/Truman and Cold War

Untitled
I never heard there was a vast Communist Conspiracy in the government - I was under the impression that McCarthy was off his rocker and never found a real communist.

By the way, "dastardly" mayy violate NPOV.

Hmph... It is evident that the article is based only on american and western sources.

Not a single word about the money reform, held in the American, French and British zones which de facto made it impossible for citizens from the Soivet zone of influence to buy/sell anything in that territory.

Concerning "in repsonse to that Soviet Union created Warsaw Pact".While NATO was created in 1949, it should not be forgotten that Warsaw Pact was created under Khruschev, more than 4 years later.

Etc, Etc. So many mistakes, blank spots, so much misleading information...

- Theocide

Copyright violation for image of Germany
This is something I think would be comparatively easy to recreate, and something that the people contributing to this project ought to consider. This image will be deleted in a week or so, unless some formal copyright attribution that is compatable with the GFDL can be granted. --Rob Horning 19:07, 2 February 2006 (UTC)

China and Communism
It would be interesting to link to international events, forces and movements that promoted changes (not only on China) and go beyond infantile propagandistic explanations. Explaining how and why some Western nations victimized China, its relations to neighboring nations would provide a better understanding about the reasons behind the path to Maoism. Making a distinction between Maoism and Marxism seems also relevant as to educate readers that there are many things behind the concept of Communism. --Panic (discuss • contribs) 02:11, 17 November 2014 (UTC)

You missed a lot of stuff about Truman
Nothing about his desegregation of the Civil Service and the military? Mercy me! Pittsburgh Poet (discuss • contribs) 23:57, 3 January 2015 (UTC)

The CIA and foreign affairs
Consider this a call for someone more informed than I am to add material about what the CIA did in the name of the United States in Central and South America and in Iran. Pittsburgh Poet (discuss • contribs) 22:53, 25 April 2015 (UTC)

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

title: Talk:US History/Truman and Cold War


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Constructivist Theories in Education/Piaget

What would Piaget (1896-1980) say to today's primary teachers to encourage a constructivist approach?

Luckily, we need not use our imagination here: Piaget dealt with elementary teachers and had very specific recommendations for them in different subject areas (Piaget, 1998, De la pédagogie. Paris: Éditions Odile Jacob). As early as 1921 he was hired by Claparède to become director of studies at the Jean Jacques Rousseau Institute in Geneva. He worked for the International Bureau of Education from 1929 to 1967 and Director of the Institute of Educational Sciences at the University of Geneva from 1932-1971.

Piaget's advice to teachers, in essence, was to provide conditions under which the child can be guided to learn for themselves: Not just to master existing knowledge, but to become excited about the possibility of creating new knowledge. What this means in different disciplines will depend on the specific topics being learned. The idea being that the student constructs their own understandings rather than being a passive recipient of knowledge.

Of course, Jean Piaget's ideas are not new. 2000 years ago, Plutarch said: "The mind is not a vessel to be filled but a fire to be kindled." Plutarch (46 - 127)


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Cookbook:Chili (Vegan)

| Vegan cuisine | Tex-Mex cuisine

Vegan chili is chili that uses no animal or meat products in its creation. Many variations of a vegetarian based chili have been created using meat substitutes, tofu and even vegetables. The most popular vegan chilis use beans as the main weight of the dish, but others use tofu, eggplant, butternut squash or zucchini.

This is a kind of chili that needs no meat (and uses no ersatz meat). Many variations are possible; the recipe is very flexible. The molasses gives this chili a somewhat Louisiana flavor.

Ingredients

 * 2 cans (30 oz) red kidney beans
 * 1 can (15 oz) black beans
 * 1 can (15 oz) navy beans
 * 1 can corn kernels
 * 1 can (6 oz) tomato paste
 * 1 medium tomato, chopped (canned diced tomato works too)
 * 2 fresh jalapeños (or your favorite chili pepper works too; more if you like it really hot)
 * 1 green bell pepper, chopped
 * 1 red or yellow bell pepper, chopped
 * 2 medium onions, chopped
 * 4 medium cloves of garlic, chopped or crushed
 * 10 ml chili powder
 * 1 large pinch salt (optional)
 * pinch of oregano
 * 10 ml olive oil (or any other kind of vegetable oil)
 * 50 ml molasses
 * Chili garlic sauce (optional)

Procedure

 * 1) In a large pot, heat the olive oil with a few drops of water. When the water starts sizzling, add the onions and garlic. Stir until the onions are soft (optionally until they are slightly brown).
 * 2) Add the chili peppers and fry for a few more seconds. Add the tomato paste and tomato, and the chili powder, salt, and oregano. Stir a few times then let boil and simmer.
 * 3) Rinse the beans well and add them to the simmering vegetables. Drain the corn and add to the chili. Add the molasses.
 * 4) Taste the chili; if it needs more seasoning, add it now (perhaps with the exception of salt, as people can add this at the table). It is probably better not to add more jalapeños at this point, but if the chili is not spicy enough, some chili sauce or chili garlic sauce can be added.
 * 5) Let the pot simmer, covered, for at least 30 minutes—longer will distribute the flavor better. If the chili is too thick, add a little water; if it's too thin, uncover the pot to let water evaporate.
 * 6) Add the bell peppers, stir, and simmer for a minute or two (peppers should stay crunchy).
 * 7) Serve with bread; Keeps well, perhaps even better the second day.

Notes, tips, and variations

 * You may add 2 cups of vegetable broth along with the tomatoes before bringing to a boil.

title: Cookbook:Chili (Vegan)


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User talk:67.68.58.20

Welcome to Wikibooks! I noticed your addition of the Vegan Chili Recipe to the Cookbook, and wanted to thank you for participating. If you'd like to continue editing here, I was hoping you'd consider creating a user account, which would allow you to do more things, like moving modules to new locations. However, logging on is optional, and you don't have to do it if you don't want to.

Again, welcome and thank you. Gentgeen 06:32, 7 May 2004 (UTC)

title: User talk:67.68.58.20


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Physics with Calculus/Mechanics/Energy and Conservation of Energy

One of the most fundamental concepts in physics is energy. It's difficult to define what energy actually is, but one useful definition might be "a measure of the amount of change taking place within a system, or the potential for change to take place within the system".

Roughly speaking, energy can be divided into two forms, kinetic and potential. Kinetic energy is the energy of movement or change. Potential energy is the energy a system has as a result of being able to undergo some change. To provide a specific example, a falling book has kinetic energy, because its position in space is changing (it is moving downwards). A book resting on a shelf has no potential energy relative to the shelf since it has a height of zero meters relative to the shelf. However, if the book is elevated to some height above the shelf, then it has potential energy proportional to the height at which it resides above the shelf.

An object can have both kinetic and potential energy at the same time. For example, an object which is falling, but has not yet reached the ground has kinetic energy because it is moving downwards, and potential energy because it is able to move downwards even further than it already has. The sum of an object's potential and kinetic energies is called the object's mechanical energy.

As an object falls its potential energy decreases, while its kinetic energy increases. The decrease in potential energy is exactly equal to the increase in kinetic energy.

Another important concept is work. Similarly to the way we defined energy, we may define work as "a measure of the amount of change brought about in a system, by the application of energy". For instance, you might do work on a book by picking it up off the floor and putting it on a shelf. In doing so, you have increased the potential energy of the book (by increasing its potential to fall down to the floor). The amount of potential energy you have "given" to the book is exactly equal to the amount of work you do by lifting it onto the shelf.

Mathematically, however, energy is very easy to define. Kinetic energy is 1/2 m v^2. Potential energy is a little bit trickier. Say we have a force which can be written as the gradient (a three-dimensional derivative. If you don't know what it is, pretend it is a normal derivative and you should be able to understand things in one dimension.) of some function, $$\phi$$ times the mass of the particle. That is $$ \vec{F} = m \vec{\nabla} \phi $$. Then potential energy is just $$m \phi + C$$ where C is an arbitrary constant. What arbitrary definitions, you might say. At first, you might think so, but it turns out, the work done by the force is the change in kinetic energy (see ../Work and Energy/). They are actually very closely related. In fact, the potential energy plus the kinetic energy due to the force is constant! Aha, so this "arbitrary" potential energy decreases at exactly the same rate this "arbitrary" kinetic energy increases. They must be the same thing in different forms! It is not so arbitrary after all. This is the conservation of energy. In fact, since the particles are moving at finite velocities, this is the much stronger local conservation of energy for mechanical systems. Another amazing fact is that it appears that all forces are conservative (this changes in electrodynamics, but energy is still conserved)! Even friction appears to be conservative on a molecular level. The slightly more mathematical treatment is available in ../Work and Energy/.

We may concisely state the following principle, which applies to closed systems (i.e. when there are no interactions with things outside the system):
 * In all physical processes taking place in closed systems, the amount of change in kinetic energy is equal to the amount of change in potential energy. If the kinetic energy increases, the potential energy decreases, and vice-versa.

When we consider open systems (i.e. when there are interactions with things outside the system), it is possible for energy to be added to the system (by doing work on it) or taken from the system (by having the system do work). In this case the following rule applies:
 * The total energy of a system (kinetic plus potential) increases by the amount of work done on the system, and decreases by the amount of work the system does.

This leads us to consider the conservation of energy and other quantities. In many cases, "you get out what you put in".

If you put 3 pairs of socks into an empty dryer, you don't need to analyze the exact configuration of the dryer, the temperature profile, or other things to figure out how many socks will come out of the dryer. You'll get 3 pairs of socks out[*].

A conservation law, in its most general form, simply states that the total amount of some quantity within a closed system doesn't change. In the example above, the conserved quantity would be socks, the system would be the dryer, and the system is closed as long as nobody puts socks into or takes socks out of the dryer. If the system is not closed, we can always regard a larger system which is closed and which encompasses the system we were initially considering (e.g. the house in which the dryer is located), even though, in extreme cases, this may lead us to consider the number of socks (or whatever) in the entire Universe!

Conservation laws help us solve problems quickly because we know that we will have the same amount of the conserved quantity at the end of some process as we did at the start. The fundamental laws of conservation are;
 * conservation of mass
 * conservation of energy
 * conservation of momentum
 * conservation of angular momentum
 * conservation of charge

Returning to our example above, the 'conservation of socks' is, in fact, a consequence of the law of conservation of mass. It should be noted that in the context of nuclear reactions, energy can be converted to mass and vice-versa. In such reactions, the total amount of mass plus energy doesn't change. Therefore the first two of these conservation laws are often treated as a single law of conservation of mass-energy

Combining these laws with Newton's laws gives other derived conserved quantities such as
 * conservation of angular momentum

Within a closed system, the total amount of energy is always conserved. This translates as the sum of the n changes in energy totaling to 0.

 * $$\sum_{k=1}^n \Delta \mathbf{E}_k = 0$$

An example of such a change in energy is dropping a ball from a distance above the ground. The energy of the ball changes from potential energy to kinetic energy as it falls.

\begin{matrix} U_g &=& m\mathbf{g}h \\ K &=& {1 \over 2} m\mathbf{v}^2 \end{matrix} $$

Because this is the only change in energy within our system, we will take a simple physical problem and model it in order to demonstrate.

An object of mass 10kg is dropped from a height of 3m. What is its velocity when it is 1m above the ground?

We start by evaluating the Potential Energy when the object is at its initial state.

\begin{matrix} U_g &=& m\mathbf{g}h \\ U_g &=& 30\mathbf{g} \\ \mathbf{g} &=& 9.807ms^{-2} \\ U_g &=& 30 \cdot 9.807 \\ U_{g3} &=& 294.21J \end{matrix} $$

The Potential Energy of the object at a height of 1m above the ground is given in a similar fashion.

\begin{matrix} U_g &=& m\mathbf{g}h \\ U_g &=& 10\mathbf{g} \\ U_g &=& 10 \cdot 9.807 \\ U_{g1} &=& 98.07J \end{matrix} $$

Hence the change in Potential Energy is given

\begin{matrix} \Delta U_g &=& 294.21 - 98.07 = 196.14J \end{matrix} $$

By definition, the change in Potential Energy is equivalent to the change in Kinetic Energy. The initial KE of the object is 0, because it is at rest. Hence the final Kinetic Energy is equal to the change in KE.

\begin{matrix} \Delta U_g &=& \Delta K \\ 196.14J &=& {1 \over 2} m\mathbf{v}^2 \\ 196.14 &=& 5\mathbf{v}^2 \end{matrix} $$

Rearranging for v

\begin{matrix} {196.14 \over 5} &=& \mathbf{v}^2 \\ \sqrt &=& \mathbf{v} \\ \mathbf{v} &\approx& 6.263 ms^{-1} \end{matrix} $$

We can check our work using the following kinematic equation.

 * $$\begin{matrix}

\mathbf{v}^2 &=& \mathbf{u}^2 + 2\mathbf{as} \\ \mathbf{v}^2 &=& 0^2 + 2\mathbf{gs} \\ \mathbf{v} &=& \sqrt{2\mathbf{gs}} \\ \mathbf{v} &=& \sqrt{2\cdot 9.807 \cdot 2} \\ \mathbf{v} &\approx& 6.263 ms^{-1} \end{matrix} $$

This follows because we can actually use the equations for energy to generate the above kinematic equation.

 * $$\begin{matrix}

\Delta U_g &=& \Delta K \\ m\mathbf{g}h &=& {1 \over 2}m\mathbf{v}^2 \\ m\mathbf{g}\Delta h &=& {1 \over 2}m{\Delta (\mathbf{v}}^2) \\ \mathbf{s} &=& \Delta h \\ \mathbf{gs} &=& {1 \over 2} \Delta (\mathbf{v}^2) \\ 2\mathbf{gs} &=& \mathbf{v}^2 - {\mathbf{v}_0}^2 \\ 2\mathbf{as} &=& \mathbf{v}^2 - \mathbf{u}^2 \\ \mathbf{v}^2 &=& \mathbf{u}^2 + 2\mathbf{as} \end{matrix} $$


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Physics with Calculus/Appendix 2/Examples of Derivatives

< Physics with Calculus

Motion
For x(t), position as a function of time

Velocity: The rate of change of position with respect to time
 * $$\begin{matrix}

\mathbf{v}(t) = f'(t) = {dx \over dt} \end{matrix}$$

Acceleration: The rate of change of velocity with respect to time
 * $$\begin{matrix}

\mathbf{a}(t) = \mathbf{v}'(t) = f''(t) = {d^2x \over dt^2} \end{matrix}$$

Jerk: The rate of change of acceleration with respect to time
 * $$\begin{matrix}

\mathbf{j}(t) = \mathbf{a}'(t) = f'''(t) = {d^3x \over dt^3} \end{matrix}$$

Jerk is not commonly used in first year motion. Its main application is in dealing with travel of large objects that change their weight as they move due to a change in mass. One example might be a rocket travelling up from rest. As it burns fuel, its centre of gravity changes and as such, its acceleration is not constant (violation of Newton's Second Law).

Mechanics (Statics)
Given the details of the loading of a beam, we can represent it on a diagram of the beam with arrows indicating forces, curved arrows indicating moments (resistance to torque) and shaded regions representing universally varying or distributed loads. We can use this diagram (commonly known as a free body diagram) and the information contained within it to draw a diagram representing the shear forces (V in the beam, and can also derive an equation that represents these. The equation may not be as simple as a polynomial, and is quite often a series of continuous functions with endpoints at the points on the beam where the forces occur.

We can perform an indefinite integral on each of these segments of the beam to get more information on it. The indefinite integrals combine to form a diagram of the bending moments in the beam. Bending moments are a special type of moment, as the beam is most likely to fail where the bending moments are at a relative extrema. By definition, any indefinite integral will contain a constant, C. In the case of the bending moment diagram, our C is merely the endpoint of the previous segment. The only exception being when we have a moment, we add or subtract its value (depending on direction).

Hence, differentiating the bending moment model will give us the shear force.

Differentiating the shear force model brings us back to our loading diagram, and differentiating that will give us the shape of the deflection of the beam under the loading.

For any bending moment model b, as a function of distance from the end of the beam, x,

\begin{matrix} b'(x) &=& V(x) \\ b''(x) &=& V'(x) &=& \operatorname{FBD}(x) \\ b'''(x) &=& \operatorname{FBD}'(x) &=& f(x) \end{matrix} $$

Where f(x) is a function describing the deflection of the beam.


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Physics with Calculus/Appendix 1/Derivatives

We define a derivative as the limit of a function as the ratio of the changes in the function and the changes in the variable as the change in the variable goes to zero.

i.e.

 * $$\begin{matrix} {df \over dx} = \lim_{\Delta x \to 0}{{f(x + \Delta x) - f(x)} \over {\Delta x}}\end{matrix}$$

An example
Quantity B is found to depend on quantity A such that B is always the square of A.

A ..... B In this case, x=A and f(x) is [the function of x] = B. Look at what happens at the point A=2 (for example).

0 ..... 0 At x=2 f(x)=4. Changing x very slightly, by only 0.01, we have delta x=0.01, so that x+delta x is 2.01.

1 ..... 1 Then the function of (x+delta x) = the function of 2.01 = the square of 2.01 = 4.0401. The difference between f(x+delta x) and f(x) 2 ..... 4 is 4.0401 and 4. It is 0.0401. Dividing it by delta x we have 0.0401/0.01 which is 4.01, meaning that 3 ..... 9 the CHANGE of the function divided by the CHANGE in x is nearly 4 when x=2. If we would have made delta x much smaller

etc. ..... we would have got exactly 4, which happens to be 2 times x at x=2

 * In general, if we have a polynomial of x, such as $$x^3,x^4,$$ etc then the derivative is as follows: $$f(x)=x^n;  \frac{d f(x)}{dx}=nx^{n-1}$$  Where $$\frac{d f(x)}{dx}$$ is the symbol for the derivative of f with respect to x.


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User talk:Ronald raygun

Hi Ronald and welcome to wikibooks, just to let you know - to sign your name type 3 tilds. To sign and date type 4 tilds. This way everyone knows who said what on a a talk page. Theresa knott 14:32, 7 May 2004 (UTC)

title: User talk:Ronald raygun


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Talk:Electronics/Symbols

Page http://wikibooks.org/wiki/Electronics:Symbols  contains images that are PNG files that have a lot of KB weight. Should they not have been exported as GIFs?

The policy is to use PNGs for all diagrams, and to only use GIFs for animations, partly because GIFs are currently encumbred by a patent. Carandol

PNG files actually have pretty good lossless compression. They're like bitmaps but with compression algorithms used. I don't think they have very much KB weight at all.

KB weight? as in kilobytes? look at the file sizes. they are usually less than 1 KB. not exactly huge files. - Omegatron 12:52, 10 May 2004 (UTC)

One thing that could be done is to take the text out of the image file then crush them with an png crushing utility see en:Wikipedia:How_to_keep_image_file_sizes_as_small_as_possible for details Theresa knott 13:14, 10 May 2004 (UTC)

 * I tried PNGCRUSH on a few of them and they are already about as small as possible. It could only reduce them by about 10 bytes max.  They are already really really small though.  <1KB is really good.  They are two-color images and compress very well.  I don't understand why someone is saying they are too big.  - Omegatron 15:51, 11 May 2004 (UTC)

 * Somewhat related. I modified Klunky.  See Electronics:Template for details. - Omegatron 23:46, 11 May 2004 (UTC)

 * It would probably be a good idea to have the text outside of the images, and also to have the images in separate files, for ease of editing. At least to have groupings like resistors, variable resistors, thermistors, etc. in separate files, and put the images next to each other, like Wanderer's BJT images.  Formatting is more difficult, that way, though.  I guess it would need tables... - Omegatron 21:06, 25 May 2004 (UTC)

Moved from article:

Not bad. The question is how big we want our pictures to be?

What would really be nice is to have some sort of circuit builder. That would be a great way to teach electronics, but it would probably be a lot of work.

Circuit builder of choice: mspaint.exe

 * I think we should use Klunky. I have mentioned this a million times.  It is easy, uniform, good look for the web, much much faster than mspaint, everyone can access it, etc. etc.  see Electronics:Template for more. - Omegatron 14:30, 30 Mar 2004 (UTC)

Greek Alphabet
The Greek alphabet in the article appears to be missing omikron (it's after xi).

Perhaps, instead of duplicating information, that section should link to http://en.wikipedia.org/wiki/Greek_Alphabet?

title: Talk:Electronics/Symbols


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Modern Physics/The Uneven Dumbbell

The kinetic energy and angular momentum of the dumbbell may be split into two parts, one having to do with the motion of the center of mass of the dumbbell, the other having to do with the motion of the dumbbell relative to its center of mass.

To do this we first split the position vectors into two parts. The centre of mass is at.

 * $$\mathbf{R}=\frac{M_1 \mathbf{r}_1 + M_2 \mathbf{r}_2}{M_1+M_2}$$

so we can define new position vectors, giving the position of the masses relative to the centre of mass, as shown.

 * $$\mathbf{r}^*_1=\mathbf{r}_1-\mathbf{R}_1 \quad

\mathbf{r}^*_1=\mathbf{r}_1-\mathbf{R}_1$$

The total kinetic energy is
 * $$\begin{matrix}K & = & \frac{1}{2}M_1 V_1^2 &+ & \frac{1}{2}M_2 V_2^2 \\

& = & \frac{1}{2}M_1 |\mathbf{V}-\mathbf{v}^*_1|^2  &+ & \frac{1}{2}M_2 |\mathbf{V}-\mathbf{v}^*_2|^2\\ & = & \frac{1}{2}(M_1+M_2)V^2 & + & \frac{1}{2}M_1 {v^*_1}^2 + \frac{1}{2}M_2 {v^*_2}^2 \\ & = & K_{ext} & + & K_{int}\\ \end{matrix} $$

which is the sum of the kinetic energy the dumbbell would have if both masses were concentrated at the center of mass, the translational kinetic energy and the kinetic energy it would have if it were observed from a reference frame in which the center of mass is stationary, the rotational kinetic energy.

The total angular momentum can be similarly split up
 * $$\begin{matrix}

\mathbf{L} & = & \mathbf{L}_{orb} & + & \mathbf{L}_{spin}\\ & = & (M_1+M_2)\mathbf{R}\times \mathbf{V} & + & (M_1\mathbf{r}^*_1 \times \mathbf{v}^*_1 + M_2\mathbf{r}^*_2 \times \mathbf{v}^*_2) \end{matrix}$$

into the sum of the angular momentum the system would have if all the mass were concentrated at the center of mass, the orbital angular momentum, and the angular momentum of motion about the center of mass, the spin angular momentum.

We can therefore assume the centre of mass to be fixed.

Since ω is enough to describe the dumbbells motion, it should be enough to determine the angular momentum and internal kinetic energy. We will try writing both of these in terms of ω First we use two results from earlier
 * $$\mathbf{L}=\mathbf{r} \times \mathbf{v} \quad \mbox{and} \quad \mathbf{v}=\boldsymbol{\omega} \times \mathbf{r}$$

to write the angular momentum in terms of the angular velocity

$$ \begin{matrix} \mathbf{L} & = & M_1\mathbf{r}^*_1 \times \mathbf{v}^*_1 & + & M_2\mathbf{r}^*_2 \times \mathbf{v}^*_2\\ & = & M_1\mathbf{r}^*_1 \times (\boldsymbol{\omega} \times \mathbf{r}^*_1) & + & M_2\mathbf{r}^*_2 \times (\boldsymbol{\omega} \times \mathbf{r}^*_2)\\ & = & M_1 \left( \boldsymbol{\omega} \left( \mathbf{r}^*_1 \cdot \mathbf{r}^*_1\right) - \mathbf{r}^*_1 \left( \mathbf{r}^*_1 \cdot \boldsymbol{\omega} \right)\right) & + & M_2 \left( \boldsymbol{\omega} \left( \mathbf{r}^*_2 \cdot \mathbf{r}^*_2\right) - \mathbf{r}^*_2 \left( \mathbf{r}^*_2 \cdot \boldsymbol{\omega}\right) \right)\\ & = & M_1 \left( \boldsymbol{\omega} d_1^2 - \mathbf{r}^*_1 \left( \mathbf{r}^*_1 \cdot \boldsymbol{\omega} \right)\right) & + & M_2 \left( \boldsymbol{\omega} d_2^2 - \mathbf{r}^*_2 \left( \mathbf{r}^*_2 \cdot \boldsymbol{\omega}\right) \right) \\ & = & (M_1d_1^2+M_2d_2^2) \boldsymbol{\omega} & - & \left (M_1 \mathbf{r}^*_1\left( \mathbf{r}^*_1\cdot \boldsymbol{\omega}\right) + M_2 \mathbf{r}^*_2\left( \mathbf{r}^*_2\cdot \boldsymbol{\omega}\right) \right) \end{matrix}$$

The first term in the angular momentum is proportional to the angular velocity, as might be expected, but the second term is not.

What this means becomes clearer if we look at the components of L For notational convenience we'll write
 * $$\mathbf{r}^*_1 = (x_1, y_1, z_1) \quad \mathbf{r}^*_2 = (x_2, y_2, z_2)

$$

These six numbers are constants, reflecting the geometry of the dumbbell.

 * $$\begin{matrix}

L_x & = & (M_1d_1^2+M_2d_2^2)\omega_x - (M_1 x_1^2+M_2 x_2^2)\omega_x \\ & &  -(M_1 x_1 y_1+M_2 x_2 y_2)\omega_y -  (M_1 x_1 z_1+M_2 x_2 z_2)\omega_z \\ L_y & = & (M_1d_1^2+M_2d_2^2)\omega_y -  (M_1 x_1^2+M_2 x_2^2)\omega_y \\ & & -(M_1 x_1 y_1+M_2 x_2 y_2)\omega_x -  (M_1 y_1 z_1+M_2 y_2 z_2)\omega_z \\ L_z & = & (M_1d_1^2+M_2d_2^2)\omega_z -(M_1 x_1^2+M_2 x_2^2)\omega_z \\ & & -(M_1 x_1 z_1+M_2 x_2 z_2)\omega_x - (M_1 y_1 z_1+M_2 y_2 z_2)\omega_y \\ \end{matrix}$$

This, we recognise as being a matrix multiplication.

\begin{pmatrix} L_x \\ L_y \\ L_z \end{pmatrix} = \begin{pmatrix} I_{xx} & I_{xy} & I_{xz} \\ I_{yx} & I_{yy} & I_{yz} \\ I_{zx} & I_{zy} & I_{zz} \end{pmatrix} \begin{pmatrix} \omega_x \\ \omega_y \\ \omega_z \end{pmatrix} $$

where

$$ \begin{pmatrix} I_{xx} & I_{xy} & I_{xz} \\ I_{yx} & I_{yy} & I_{yz} \\ I_{zx} & I_{zy} & I_{zz} \end{pmatrix} = \begin{pmatrix} M_1(d_1^2-x_1^2)+M_2(d_2^2-x_2^2) & -(M_1 x_1 y_1 + M_2 x_2 y_2) & -(M_1 x_1 z_1+M_2 x_2 z_2) \\ -(M_1 x_1 y_1 + M_2 x_2 y_2) & M_1(d_1^2-y_1^2)+M_2(d_2^2-y_2^2) & -(M_1 y_1 z_1+M_2 y_2 z_2) \\ -(M_1 x_1 z_1 + M_2 x_2 z_2) & -(M_1 y_1 z_1+M_2 y_2 z_2) & M_1(d_1^2-z_1^2)+M_2(d_2^2-z_2^2) \end{pmatrix} $$

The nine coefficients of the matrix I are called moments of inertia.

By choosing our axis carefully we can make this matrix diagonal. E.g if
 * $$\mathbf{r}^*_1 = (d_1, 0, 0) \quad \mathbf{r}^*_2 = (-d_2, 0, 0) $$

then

\begin{pmatrix} I_{xx} & I_{xy} & I_{xz} \\ I_{yx} & I_{yy} & I_{yz} \\ I_{zx} & I_{zy} & I_{zz} \end{pmatrix} = \begin{pmatrix} 0 & 0 & 0 \\ 0 & M_1 d_1^2 +M_2 d_2^2 & 0 \\ 0 & 0 & M_1 d_1^2 +M_2 d_2^2 \end{pmatrix} $$

Because the dumbbell is aligned along the x-axis, rotating it around that axis has no effect.

The relationship between the kinetic energy, T, and ω quickly follows.

 * $$\begin{matrix}

2T & = & M_1 {v^*_1}^2 & + &  M_2 {v^*_2}^2\\ & = & M_1 \mathbf{v}^*_1 \cdot (\boldsymbol{\omega} \times \mathbf{r}^*_1) & + & M_1 \mathbf{v}^*_2 \cdot (\boldsymbol{\omega} \times \mathbf{r}^*_2) \\ & = & M_1 \boldsymbol{\omega} \cdot (\mathbf{r}^*_1 \times \mathbf{v}^*_1) & + & M_2 \boldsymbol{\omega} \cdot (\mathbf{r}^*_2 \times \mathbf{v}^*_2) \end{matrix}$$

On the right hand side we immediately recognise the definition of angular momentum.

 * $$T=\frac{1}{2} \boldsymbol{\omega} \cdot \mathbf{L}$$

Substituting for L gives

 * $$T=\frac{1}{2} \boldsymbol{\omega}\mathbf{I}\boldsymbol{\omega}$$

Using the definition
 * $$\boldsymbol{\omega} = \omega \mathbf{n} \quad

\mathbf{n} \cdot \mathbf{n}=1 $$

this reduces to

 * $$T=\frac{1}{2} I \omega^2 $$

where the momement of inertia around the axis n is

 * $$I=\mathbf{n} \mathbf{I} \mathbf{n} $$

a constant.

If the dumbbell is aligned along the x-axis as before we get
 * $$T=\frac{1}{2} (M_1 d_1^2 +M_2 d_2^2) (\omega_y^2+\omega_z^2)$$

These equations of rotational dynamics are similar to those for linear dynamics, except that I is a matrix rather than a scalar.

title: Modern Physics/The Uneven Dumbbell


text:
Cookbook:Cuisine of Ireland

| European cuisines

Irish stew The stew is made with mutton or lamb, potatoes and onions; in the south carrots are included too. The liquid may be water or stock, and is sometimes thickened with barley.

Beef and Guinness Casserole This is one you have to try. Back when the Irish had nothing, drink was the main diet. It was food... they used to call the pint the 'liquid food'. Nowadays the 'liquid food' is used increasingly in cooking (keeping to our roots). It is a tasty addition to stews and casseroles, helping to tenderize the meat and imparting its distinctive malty flavor to any dish. This recipe makes a wonderful gusty stew which tastes even better a day or two after it is made

Tripe and Drisheen is a classic Cork (south county) recipe for the more adventurous, as are Crubíns (Pigs' Feet). A pig's foot may be used to thicken a stew.

Boiled cabbage and bacon, boiled in the same pot. Soak the bacon in water for a night before to make it less salty, and boil it with new water. Smoked bacon is preferred.

Many excellent wild game dishes which are not common enough but can include Guinea Fowl, Pheasant, Snipe, Venison and such like.

Ulster Fry - cooked breakfast dish. Many variations but standard fry consists of: Soda bread, potato bread, pancake, sausages (one pork, one beef), bacon rashers, mushrooms, fried egg(s), tomato, vegetable roll (some versions include a slice of steak) and a cup of tea. Heavy on cholesterol, carbohydrates and HBV proteins, some of the meat based ingredients can be substituted with beans, potato waffles or hash browns. For a healthier version, grill the meats, omit the vegetable roll and poach the eggs.

Rashers (bacon) and sausages and fried eggs. Mostly for breakfast or for lunch, but along with white pudding and black pudding they can be eaten in a roll or a sandwich. Many cafes provide "all-day breakfasts" due to the demand. Hash browns, baked beans or potato waffles might also be included (but not in a bread roll). Delis offer fresh pastries such as sausage rolls and jambons.

Tea and Toast. Irish people especially like teas from Sri Lanka, often still named as Ceylon teas. English Breakfast and Darjeeling are popular. Toast is typically made in a dedicated pop-up toaster.

Ham and cheese sandwiches, toasted if possible. Ideally use real cheese and real ham, but cut the fat off the ham.

Chips, curried chips, burgers and chips, or spice bags are popular, especially after a night of drinking.

title: Cookbook:Cuisine of Ireland


text: Template:Russian

title: Template:Russian


text:
PHP Programming/Beginning with "Hello World!"

This page makes use of Color Code Boxes. Use the [ discussion page] to leave any feedback regarding this new feature.

Return to The Basics.

Simple Hello World
"Hello World." is the first program most beginning programmers will learn to write in any given language. Here is an example of how to print "Hello World!" in PHP.

This is as basic as PHP gets. Three simple lines, the first line identifies that everything beyond the  tag). The second and third lines write a text greeting on the web page. This next example is slightly more complex and uses variables.

Hello World With Variables
This example stores the string "Hello World!" in a variable called $string. The following lines show various ways to display the variable $string to the screen.

The previous example contained two outputs. PHP can output HTML that your browser will format and display. The PHP Output box is the exact PHP output. The HTML Render box is approximately how your browser would display that output. Don't let this confuse you, this is just to let you know that PHP can output HTML. We will cover this much more in depth later.

Variables
Variables are the basis of any programming language: they are "containers" (spaces in memory) that hold data. The data can be changed, thus it is "variable".

If you've had any experience with other programming languages, you know that in some of the languages, you must define the type of data that the variable will hold. Those languages are called statically-typed, because the types of variables must be known before you store something in them. Programming languages such as C++ and Java are statically-typed. PHP, on the other hand, is dynamically-typed, because the type of the variable is linked to the value of the variable. You could define a variable for a string, store a string, and then replace the string with a number. To do the same thing in C++, you would have to cast, or change the type of, the variable, and store it in a different "container".

All variables in PHP follow the format of a dollar sign ($) followed by an identifier i.e. $variable_name. These identifiers are case-sensitive, meaning that capitalization matters, so $wiki is different from $Wiki.

Real world analogy
To compare a variable to real world objects, imagine your computer's memory as a storage shed. A variable would be a box in that storage shed and the contents of the box (such as a cup) would be the data in that variable.

If the box was labeled kitchen stuff and the box's contents were a cup, the PHP code would be:

If I then went into the storage shed, opened the box labeled kitchen stuff, and then replaced the cup with a fork, the new code would be:

Notice the addition of the   in the middle and the   at the end of the code block. The   is the assignment operator, or in our analogy, instructions that came with the box that states "put the cup in the box". The   indicates to stop evaluating the block of code, or in our analogy, finish up with what you are doing and move on to something else.

Also notice the cup was wrapped in single quotes instead of double. Using double quotes would tell the PHP parser that there may be more than just a cup going into the box and to look for additional instructions.

Single quotes tell the PHP parser that it's only a cup and not to look for anything more. In this example the bathroom box that should've had its contents added to the kitchen box has its name added instead. So again, try to visualize and associate the analogy to grasp the concept of variables with the comparison below. Note that this is a real world object comparison and  NOT PHP  code. Computer memory (RAM) = storage shed Variable = a box to hold stuff Variable name = a label on the box such as kitchen stuff Variable data = the contents of the box such as a cup

Notice that you wouldn't name the variable, as the relationship between the variable and the box is represented by the   and how the data is stored in memory. For example, a constant and array can be considered a type of variable when using the box analogy as they all are containers to hold some sort of contents, however, the difference is on how they are defined to handle the contents in the box.

 : a box that can be opened while in the storage shed to exchange the contents in the box.

 : a box that cannot be opened to exchange its contents. Its contents can only be viewed and not exchanged while inside the storage shed.

 : a box that contains one or more additional boxes in the main box. To complicate matters for beginners, each additional box may contain a box as well. In the kitchen stuff box we have two boxes, the clean cup box and the dirty cup box

More on variables, from the PHP manual

The print and echo statements
Print is the key to output. It sends whatever is in the quotes (or parentheses) that follow it to the output device (browser window). A similar function is echo, but print allows the user to check whether or not the print succeeded.

When used with quotation marks, as in:

The quoted text is treated as if it were a string, and thus can be used in conjunction with the concatenation (joining two strings together) operator as well as any function that returns a string value.

The following two examples have the same output.

The dot symbol concatenates two strings. In other programming languages, concatenating a string is done with the plus symbol and the dot symbol is generally used to call functions from classes.

Also, it might be useful to note that under most conditions echo can be used interchangeably with print. print returns a value, so it can be used to test, if the print succeeded, while echo assumes everything worked. Under most conditions there is nothing we can do, if echo fails.

The following examples have the same output again.

We will use echo in most sections of this book, since it is the more commonly used statement.

It should be noted that while echo and print can be called in the same way as functions, they are, in fact, language constructs, and can be called without the brackets. Normal functions (almost all others) must be called with brackets following the function identifier.


text:
PHP Programming/Get Apache and PHP

Get Apache
To get Apache, first you must go to the Apache website. From there, find the section for the HTTP Server Project, and then the download page. Unless you have an understanding of compiling an executable from the source code, be sure you download the binary (for Windows users, I recommend the latest (2.0.52) MSI installer package).

Once you've obtained an Apache installer, whether an EXE or an MSI or what have you, run it. Apache will prompt you (eventually) for several (three) pieces of information. Following this are, very basically, your choices regarding what to input:
 * Network Domain: Either your domain name (.com/.net/.whatever) or your workgroup. If you are not sure if you have either, you probably don't; "User" is sufficient.
 * Server Name: I'm really not sure what to put here other than "localhost", as that's the only server I have.
 * Administrator's E-mail: Your personal e-mail address. This is appended to default error messages and the like.

When given an option between running on when started and running as a service, I recommend using Apache as a service. This means that it will run when Windows begins, saving you the trouble of using the Start menu to start it every time you want to use it. To start Apache manually: Start > All Programs > Apache... > Control Apache Server > Start Apache In Console.

''Note: you will also see some other options, like an option to stop Apache and an option to restart Apache. You will need to be able to control the server later. Alternatively, when I run Apache, I get an icon in the system tray next to the clock. I can right-click this icon and it has options to stop and restart the Apache server. This system tray icon should appear by default on the windows installation.''

Once the install is finished, you'll have Apache installed. However, it's not yet configured. Before we do so, though, let's test Apache to see if the installation went according to plan. You should be able to now, if the server is started, run your preferred browser and type "http://localhost/" or, if your computer is on a network, the name of the computer (in my case "http://dellpc/"). You should see a page with the message "If you can see this, it means that the installation of the Apache software on this system was successful." Congratulations!

Configure Apache
First, you must set up a location for your files to be stored. I created a folder in an easy to remember and easy to type location. All of my documents are stored in the folder "C:/Web/". In this folder, I also included a shortcut to the httpd.conf document in the Apache folder for easy modification.

This httpd.conf document is located in the conf directory of where Apache is installed. On my computer this location is "C:/Program Files/Apache Group/Apache2/conf/". Regardless of where it is, find it and open it before continuing.

This file is the primary (if not only) configuration file for your Apache server. The size and amount of words looks intimidating, but really most of them are comments; any line that begins with a hash mark / pound sign (#) is a comment. Find (using ctrl+f), "DirectoryIndex" and you will eventually see a line that reads DirectoryIndex index.html index.html.var. We are going to change that to read DirectoryIndex index.html index.html.var index.php index.htm. This means that if an index.html is not found in your web directory, the server will look for an index.php, and then will look for index.htm if index.php is not found. Go ahead and save the file. Fantastic. For the changes to take effect, you must restart the server.

To define where your web folder is, find (via ctrl+f) "DocumentRoot". Replace what follows "DocumentRoot" in quotes with the full path to your web directory. If you're using C:/Web/ as your web directory, your line would read DocumentRoot "C:/Web/". Scroll down a tad to find the comment line that reads "This should be changed to whatever you set DocumentRoot to." Change the following line to read <Directory "C:/Web/"> or whatever you set DocumentRoot to.

Testing Apache
You should have a functioning Apache server now. You can test this by first restarting Apache, then placing an HTML file in your web directory named "index.htm" and then accessing it by opening your browser and browsing to http://localhost/. If you see your index.htm, excellent work.

''Note: for a while, I would see the Apache test page if I just went to http://localhost/ or http://dellpc/. To see my index page, I would have to go directly to that file, i.e. http://localhost/index.htm. Eventually, this just stopped happening. I'm not sure what happened.''

''This probabally happened because the Apache test page was cached. This means your web browser had stored a copy of it locally and was serving that file instead of the real webpage. Hitting refresh should fix this problem.''

Since Apache is configured and working, all that's left is to download, install, and configure PHP, and then reconfigure Apache to use it.

Get PHP
The PHP website is the home of PHP on the web. There you can download PHP and also find the PHP manual. In any language, having a manual is a huge help.

Navigate to the downloads page and find the latest ZIP package. At the time of this writing, the current version is 4.3.9, and the ZIP package is here. Unzip, via WinZip or WinRAR or PKUnzip or whatever decompressing program you use, to the root (C:/, usually) directory. It will leave a folder called "php-...". Rename this folder to "php", and it is in this C:/PHP/ directory that your new script interpreter now resides.

Note: There is also an installer available for PHP, but I do not recommend this as using it shall lessen your knowledge of how PHP works.

''PHP 5.0.2 is also available for download. This is a newer code base and generally has a greater performance, and more capabilities than then 4.x.x line. It is generally advised that you use the 5.x.x line in preference to 4.x.x. The code for PHP5 is very similar to the code for PHP4, and everything covered in this book should work under both environments.''

Configure PHP
In your C:/PHP/ directory, find the files called "php.ini-dist" and "php.ini-recommended". These are two separate files that are included with PHP that contain separate configurations for PHP depending on your needs. The PHP website recommends you use the recommended version, so you need to rename this to "php.ini".

Here you have a choice. At this stage you need to make the file accessible to your webserver and the PHP parser. You can either: LoadModule php4_module "c:/php/sapi/php4apache2.dll" AddType application/x-httpd-php .php
 * Simply move it to C:/WINDOWS/ and then make two shortcuts. One of these belongs in the C:/PHP/ directory and the other being in the web directory. This makes it easy to find while working with either PHP or the files in the web directory.
 * Or (if you have Apache 2) make it available to Apache in its PHPIniDir directive in the httpd.conf file. In order to do this, simply open httpd.conf, scroll to the bottom and add one of these lines:
 * 1) If you chose PHP 4 insert this:

LoadModule php5_module "c:/php/php5apache2.dll" AddType application/x-httpd-php .php
 * 1) If you chose PHP 5 insert this:

PHPIniDir "C:/php"
 * 1) configure the path to php.ini
 * (remembering to change C:/php if you put the PHP folder anywhere else)

AddType application/x-httpd-php-source .phps
 * Additionally, if you would like Apache to colour highlight your PHP source files, add the following line directly below:

In php.ini, find "doc_root". Much like you did with the Apache DocumentRoot directive, make the line read doc_root = "c:\web" or whatever your web directory is. Scroll down a tad (or find) to reach the extension_dir line. After the equals sign, type, in quotes, the directory in which PHP is located. For people following along, this would be C:/PHP/. My extension_dir, for instance, reads <tt>extension_dir = "c:\php"</tt>.

Finally, you need to make the relevant DLL's available to the web server. Again, there are a number of different ways of doing this. I recommend the final method because it will allow you to easier upgrade PHP in the future, should you choose to do so. The DLL's are <tt>php4ts.dll</tt> and <tt>php5ts.dll</tt> depending on the version of PHP that you are installing.
 * You can simply copy the DLL to the <tt>C:\Windows\</tt> directory.
 * Or to the web server's directory (e.g. <tt>C:\Program Files\Apache Group\Apache2\bin</tt>)
 * Or you can add the PHP directory to the Windows PATH. There are different ways of doing this depending on your version of Windows:
 * In Windows 98/Me you need to edit autoexec.bat:
 * Look through the file until you find an entry with <tt>PATH=C:\WINDOWS;C:\WINDOWS\SYSTEM...</tt> etc. Simply append <tt>;C:\PHP</tt> to the end of it.
 * Save the file (make sure that you make a backup first) and restart your computer.
 * On Windows NT/2000/XP and Server 2003, you need to change the PATH in the <tt>Environment Variables</tt> pane.
 * Open the System panel from the Control Panel.
 * Click on the Advanced tab, click on the button to open the "environment variables". Look in the pane for System Variables.
 * Find the PATH entry and double-click on it. Add ";C:\PHP" to the end of the line.
 * Click OK and restart your computer.

title: PHP Programming/Get Apache and PHP


text:
User:Nsoyeblcyha

For more information, see my Wikipedia profile.

Contributions
I contributed to some things ages ago but those contributions have long since been overwritten.

title: User:Nsoyeblcyha


text:
User:Angela

I first edited Wikibooks on 10 September 2003. Most of my edits here are moving articles from the English Wikipedia via the transwiki system, especially recipes which I believe better fit the Wikimedia Cookbook than the encyclopedia. As a former developer of student assessments, I am interested in the Wikiversity project. I am also interested in collaborating with related projects.

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text:
Cookbook:Grilling

Grilling is a fast, dry method of cookery which uses the intense heat radiated by an:

 * electrical element,
 * gas flame,
 * glowing charcoal or an open wood fire.

The heat source can be either above or below the food (or both) and the heat, in the form of infra-red waves, is transferred to the surface of the food. Infra-red waves penetrate only about 1 mm into food (whereas microwave radiation penetrates about 40 mm/l½ in.)

Heat is transferred from the surface to the centre of the food by conduction. (If the food comes into contact with hot grill bars, which is almost certain to happen, there is also some conduction at the surface.)

It is important that the grill is preheated so that it reaches the high temperatures necessary for efficient infra-red radiation.

Grilling cooks fast because:

 * very high temperatures are used
 * the food can be positioned close to the heat source
 * the energy passes from the heat source almost instantly, without having to be carried in a liquid or through much air.

How much heat the food absorbs depends on the colour of its surface: darker foods tend to absorb the infra-red more easily than light ones (which reflect some of the heat). This is the same effect as a black car getting hotter in the sun than a white car (or why a person in a white shirt stays cooler in the hot sun in the summer than the same person would wearing a black shirt.)

Grilling and radiant heat
When you put your hand near a hotplate or a room radiator or in direct sunlight the glow you feel is the result of infra-red heat radiation.

Infra-red radiation works without any physical contact between the source of heat and the object, but the energy is lost quickly because the rays spread out in all directions, so during cooking the object needs to be quite near the heat source.

The food is placed at a distance from the heat source which will brown the surface as required, while cooking the centre to the degree of doneness required. The best temperature for meat is in the range 150°-200°C (300°-390°F) at a distance of 10 to 15 cm (4 to 6 in.) from a typical overhead grill (which will be at a much higher temperature -around 1,000°C or 1,800°F).

Browning
Browning cannot occur at low temperatures, which is why food that is cooked at boiling point (as in steaming and microwaving) does not brown. When the food is exposed to the radiant heat of a grill, the surface rapidly browns and develops an intense, full flavour. In foods with a high sugar content, the sugar caramelises, first melting and then deepening in colour, and also creating a rich flavour (this is the same mechanism as the browning of toast.

In foods such as cakes, meats, nuts and coffee beans, the carbohydrate part of the food reacts with other parts of it and the result is browning. This is sometimes called the Maillard reaction after the Frenchman who discovered how it happened.

With meats, the browning stage is sometimes called searing. It used to be thought that searing actually sealed the surface of the meat, but this is not the case.

How to control the degree of cooking
In grilling, the radiated heat is very intense and the surfaces of the food brown rapidly. But there is a big difference between the speed of cooking at the surface and inside the food, and it is important that surface browning occurs at about the same rate as the internal cooking.

In an overhead grill this means adjusting the distance of the food from the heat source and in a charcoal grill you might need to move the food to a cooler area after initial browning.

Otherwise it is easy to end up with food that is either charred on the outside and under-cooked or even quite cold on the inside or completely dried out, tough (even tender meat will toughen in these conditions) and burnt.

Choice of food for grilling
Only certain types of food are suitable for the intense dry heat of grilling.

In general they should be tender items which are:

 * of good quality
 * small (large joints of meat must be cut into thin slices or steaks)
 * regular in shape to ensure even cooking.

Meat should have a reasonable fat content - veal escalopes, for example, are so lean that they will just dry out.

Tough cuts of meat are unsuitable for grilling, because the temperatures are too high, the conditions too dry and the time too short for the connective tissue to be converted into gelatin.

Tomatoes and mushrooms grill successfully, particularly if they are first brushed with oil, but vegetables with a low moisture content will rapidly dry out and shrivel.

Other meanings of the term
Grilling is also an ambiguous term that can mean:

Double-sided Frying
This would be done in a sandwich cooking device, similar to a waffle iron but preferably without the square bumps. The George Foreman Grill works fairly well. The procedure is sometimes also known as toasting, as in the toasted cheese sandwich.

Broiling (British English usage)
Most British and European ovens are fitted with radiant grills: an overhead gas or electric radiant heating element cooks the food below, which lies on a "grill" or rack (the grill usually rests in a tray that catches drips from the food). The same term is also used to describe the cooking technique where food lying on a rack is cooked by radiant heat from below, as in a barbecue.

If no radiant grill is fitted, this is best done in an electric oven, with the door partly open and only the top heating element in use. Gas ovens often provide a less-effective lower drawer for this purpose.

The same can be achieved outdoors by vertical grilling, using either stacks of charcoals or fires with high flames fed by standing pieces of thin and long burning-wood. The food will then be placed to receive infrared radiation from the side.

Barbecuing
This cooking method uses fire. It is usually done outdoors on barbecue grills over wood, charcoal, or propane fires. In some areas, the term barbecuing is reserved for a slow low-heat cooking process that operates at about 220°F (105°C) and the term grilling is used for a fast high-heat cooking process. In other areas, all barbecuing is considered grilling and all grilling over a fire is considered barbecuing. Barbecuing is traditionally done with hardwoods or fruitwoods, such as hickory, maple, mesquite, and applewood, which gives a nice smoke flavor to the food.

The meats, fish or vegetables may be prepared by marinating or by applying a combination of spices known as a dry rub. Marinated meats can also be ‘mopped’ with the marinade while cooking. A barbecue sauce may be added before, during, or after cooking.

Barbecue also can mean a device for cooking such food, a social event at which such food is served, or any food served with barbecue sauce.

Recipes that use some form of grilling

 * Boerewors
 * Campfire Trout
 * Grilled Cheese Sandwich
 * Grilled Peanut Butter Sandwiches
 * Grilled Vegetable Sandwich
 * Midwestern Chicken Wings
 * Hamburger Deluxe
 * Maple Syrup Planked Salmon

title: Cookbook:Grilling


text:
Cookbook talk:Grilling

This module uses text originaly published in the Wikipedia article Grilling. The page history of that article at the time the text was coppied is included below.

* (cur) (last). . 07:46, 21 Apr 2004. . Stormwriter (Removed following line: ITOM 2308!) * (cur) (last). . 07:44, 21 Apr 2004. . 129.119.91.181   * (cur) (last). . 02:22, 14 Feb 2004. . Minesweeper (*George Foreman Grill) * (cur) (last). . 18:53, 26 Jan 2004. . 66.76.71.112   * (cur) (last). . m 05:23, 23 Nov 2003. . Wik * (cur) (last). . 19:35, 2 Apr 2003. . 24.60.35.134 (removed extra "a" before cooking in last paragraph) * (cur) (last). . 18:23, 16 Jan 2003. . 203.97.103.237 (add skewers) * (cur) (last). . 07:49, 6 Jan 2003. . 192.85.47.2   * (cur) (last). . m 05:05, 31 Dec 2002. . Modster * (cur) (last). . m 18:09, 12 Dec 2002. . 80.132.139.148 (de:) * (cur) (last). . 22:10, 19 Sep 2002. . 65.56.188.227   * (cur) (last). . m 21:44, 19 Sep 2002. . 203.192.36.156   * (cur) (last). . 21:38, 19 Sep 2002. . 203.192.36.156   * (cur) (last). . m 12:15, 22 May 2002. . Maveric149 (from ugly / page)

Edit war
OK, the anonymous IP had asked me to look this over... I'm not going to argue over which terms mean which because I don't know, although I must say which meanings are most common should be considered the "correct" meanings with the others still being noted to avoid confusion. Two sources (Wikipedia and Merriam-Webster) are not really enough to judge that unless they contain that info. There must be a way for you two to come into agreement without an admin putting his foot down.

I do see that User:AlbertCahalan seems to have his own idea of what the page should be like and until now was reverting anything to the contrary. I don't see why this should be done; what's wrong with expanding it? This is a wiki. We don't own pages. If somebody wants to expand them, let them, or if you insist on not doing so, at least point out why it's better not to ("this is a disambiguation page" does not cut it). Now, I'm not saying I'm on anybody's side as far as the edit war goes, I'm just saying useful content should not be reverted for no apparent reason -- and certainly not while calling the contributing party a vandal, at that! - Furrykef 20:13, 10 May 2005 (UTC)

 * I think the main issue was over whether the cooking method is "direct" or "indirect". I'm not sure how to make that distinction (how direct is direct; is microwave the only direct way?), but it doesn't matter in any case. So, best not to mention it. I'm not 100% sure what you mean by useful content being reverted, but the barbeque instructions were written by me and originally placed on the barbeque page. They belong there, not on the grilling page. Given that little is said about the distance from the flame, the instructions should suit either the normal barbeque definition or the strange narrow definition. I pointed out more info on the user's talk page. I think there is much less for him to object to now, ever since the removal of the useless direct/indirect distinction. AlbertCahalan 21:23, 10 May 2005 (UTC)

 * Ah, I didn't notice that content was moved rather than added, sorry. Still, I don't think it was worth an edit war. I do agree that "direct" versus "indirect" doesn't seem to be a useful distinction and we're probably better off without it. No comment on where things belong, though. - Furrykef 23:04, 10 May 2005 (UTC)

 * I'd be happy to hear any suggestions for better ways to deal with someone who insists on a very non-standard definition of barbecue while making the Cookbook:Grilling page too wordy to serve as a disambiguation page. Note that I did attempt to discuss things on "his" anon talk page. When that fails...? AlbertCahalan 00:18, 11 May 2005 (UTC)

Is the Wikipedia entry non-standard? I don't understand how one part of Wiki can say one thing and yet when I try to apply it into another part, its wrong. Read the Joy of Cooking. Read any barbecue cookbook. Read about Mexican history (barbacoa). Go to a barbecue competition or restaurant. And Albert did not try to discuss anything with me, he only accused me of being wrong. I've conceded that barbecue can be taken to mean grilling, but to professional cooks and purists it means something else entirely. The biggest problem with the original page is it confuses both definations. If you mean barbecuing as in grillign high heat/fast cooking then delete the the 'popular in the Southern US' as this is popular the world over but if you mean barbecue as in ribs etc, then its slow cooked which necessarily requires indirect heat. I hope my latest attempt shows that I am willing to compromise AND that I really know what I'm talking about. 207.171.167.101 07:44, 16 May 2005

 * Yes, the wikipedia entry is non-standard. I'm working to get it fixed. In any case, "grilling" means at least 3 different kinds of cooking. (double-sided frying, broiling, and all types of barbeque) So the grilling page needs to cover that. In general, it can direct readers elsewhere: Cookbook:Frying, Cookbook:Broiling, and Cookbook:Barbecuing. So I do insist that this page do that. I also insist that the barbeque instructions not disappear or get moved over here, but I might accept moving them to a different page. (they are somewhat specific to making beef burgers on a wood fire) DO NOT MOVE VIA CUT-AND-PASTE. Suggest a good name, and I'll move the instructions. All cooking uses indirect heat, except perhaps microwave (where the heat is generated in the food), so let's avoid that useless distinction. If you allow more than microwaving to be considered direct, then all forms of grilling and/or barbecuing are direct. AlbertCahalan 19:25, 16 May 2005 (UTC)

 * Your barbecue/grilling distinction fails because there is no place to draw the line. What would you call what I do with burgers? For brief moments, they may be in the flames. ("Grilling!" you may think) Often though, there are no flames at all and the burgers are bathed in smoke. They even get the reddish tint from carbon monoxide, just as is claimed by the "barbecue purists". So is it barbecuing then? Both? I have no trouble describing this, because I use the normal definition of barbecue. No matter what I do with the fire I'm barbecuing, which is a type of grilling. AlbertCahalan 16:27, 16 May 2005 (UTC)

 * Please sign posts in the future, using 4 tilde (squiggle, likely near your "1" key) characters. To you, it should look like ~ before you save the page. (you can see the result in the preview though) I signed your text for you; you should take care of it yourself. AlbertCahalan 16:27, 16 May 2005 (UTC)

Great job being an idiot. If you acutally knew what slow barbecuing is (which by your burger analogy you obviously don't), then you would not mistake burgers on a gas grill for ribs and pork on a pit over slow-burning wood. Once again, grilling is the general cooking of meat with open flame, while barbecue is specifically cooking food over a slow-burning flame for a long period of time. Haverton 20:59, 25 May 2005 (UTC)

 * Great job having a polite debate. I certainly don't use a gas grill; I cook over real chunks of mesquite wood. Sometimes they burn very slowly, with no flame and maybe lots of smoke, and sometimes they have flames. Outside your neck of the woods, barbecuing is normally fast and it is always considered a type of grilling. It might even involve a gas barbeque. AlbertCahalan 03:38, 26 May 2005 (UTC)

As a chef
Grilling to me is controlling the Mallard Reaction using direct heat. Even throwing a tortilla on an electric burner is grilling to me. --68.127.162.10 02:47, 9 September 2005 (UTC)

title: Cookbook talk:Grilling


text:
Cookbook talk:French Toast

This module was the featured recipe on the main Cookbook page from May 8, 2004 - May 16, 2004.

with baguettes
Has anyone tried making french toast with french bread (baguettes)? how did it go?Xmnemonic 05:46, 5 Sep 2004 (UTC)

Vegan alternative recipe:
1 cup soy milk. 1 and a half tablespoon of flour. 2 teaspoon of sugar or sweetener of your choice. 2 teaspoon of vanilla. 1 teaspoon salt. Pinch of nutmeg. and 5 slices whole wheat bread.

Optional - 1/4 teaspoon of turmeric or less (less is better).

Tips: - Use slain bread, coat both sides and avoid over heating.--24.57.59.196 (talk) 21:06, 10 March 2009 (UTC)

French Toast in Spain
In Spain we call them "torrijas" or "tostadas de Santa Teresa". It is a very typical food.

title: Cookbook talk:French Toast


text:
Using GNOME/Main desktop

When you log in to gnome, you will appear on the main desktop.?! This chapter will explain the items you are likely to see on the desktop.

 * 1) Desktop area
 * 2) Application windows
 * 3) File manager
 * 4) Menus
 * 5) Panel
 * 6) Applets
 * 7) Preferences

title: Using GNOME/Main desktop


text:
Using GNOME/History of GNOME

GNOME was started in late 1997 due to unhappiness over licensing problems with KDE. In 1999 the first version was released.

In late 2001 the main focus switched to usability and GNOME 2.0 was released in June 2002. Gnome 2.6, was released in March 2004. Releases occur every six months. The current release is 3.22.

See also: http://www.linuxvalley.com/encyclopedia/ldp/lg/issue35/icaza.html

title: Using GNOME/History of GNOME


text:
Using GNOME/Differences with Windows

If you are used to Microsoft Windows, here are the differences you will find.

Taskbar
There is no taskbar. The clock is located at the top of the screen. GNOME does not provide a list of buttons to switch between each window.

Start Menu
By default, there is no start menu in GNOME. However, it is easy to enable an Applications menu that works very much like the Windows start menu. Programs in the Applications menu are listed by category (Graphics, Internet, Office, and so on) rather than in alphabetical order.

My Documents
Like modern versions of Windows, GNOME provides four different folders for your documents: Documents, Music, Pictures, and Videos. All of these folders are contained within your “home folder.” To see your home folder, launch the Files app. A new copy of the Files app will display the contents of your home folder by default.

My Computer
External disks such as thumb drives appear in the list at the left of the Files app automatically when they are plugged in. Linux doesn’t use drive letters like A: or C:. Instead, drives are given more logical names. Viewing the contents of your hard drive is more complicated.

Control Panel
GNOME’s Control Panel is called Settings. You can find a few more options in the “Extensions” app as well.

Recycle Bin
GNOME calls this the Trash. (In some languages, it is called the Wastebasket instead.) It works just like the Recycle Bin in Windows. You can find it on the left side of a Files app window.

Windows Explorer/File Manager
In GNOME, this is called the Files app. You can find it in the Applications menu or the Activities screen.

title: Using GNOME/Differences with Windows


text:
OpenOffice.org/Installation

Microsoft Windows
First you need to get an OpenOffice installer package. Before downloading the Office Package, you'll need to review the system requirement. After you read it, download an appropriate installation package or use P2P download or order a CD-ROM. You might want to use a download manager if you're using direct download.

For some functionality to work, OpenOffice need Java Runtime Environment (JRE) to be installed on the computer. If you're not sure you do have JRE installed, you could include JRE in your OpenOffice package.

Installation of both the JRE and OpenOffice.org is as simple as following a fairly standard installation routine in Windows. The installation wizard first explains that it will allow you to install OpenOffice.org. After you click on "Next", it prompts you to read and accept the terms of service. Clicking next again allows you to choose a directory in which to install the software. You are then offered a choice between full installation of all features and a screen which would allow you to choose which components to install. After this point, the installation wizard runs for a time, with several progress bars and a running list of which file is being copied.

You can now open OpenOffice.org from the task bar (if you set up quickstarter during install) or its program group. From the program group you then select the tool you need. To use quickstarter right-click on it and select the tool you need.

GNU/Linux
Most GNU/Linux distributions come with OpenOffice.org preinstalled. It is simply necessary to choose the appropriate option for installation. Be aware, however, that some of the packaged files, such as RPMs, do not include some features that conflict with the distro licenses, as they are packaged by the distributors. Java support is one item frequently left out of these versions. However, some distributions configure it to run with an alternative free software Java Runtime Environment from the Free Software Foundation.

It can be installed in RPM or DEB form manually by navigating to the same download page as for installing under Windows, and selecting the operating system as Linux after choosing the language, then choosing whether you want to download an RPM (For Red Hat, Fedora Core, SUSE, Mandriva, etc.) or DEB (for Debian, Ubuntu, etc.) file. This can then be installed with the package manager provided with your distribution.

OpenOffice.org can also be downloaded in source code form by choosing 'Source and Solver' from the main download page, but this isn't necessary for most users not interested in development.

Debian and Derivatives
Debian and its derivatives (e.g. Ubuntu) use apt-get, aptitude, and synaptic as their package manager. You can install OpenOffice.Org by running either of these in the Terminal:

or

or by using the graphical package manager.

Mac OS X
In order to run OpenOffice.org on MAC OS X, X11 is required. MAC OS X versions before Tiger (10.4.x) required a separate application to be downloaded from Apple. With Tiger X11 is available on the OS X Install Disk. You can find this in the System/Installation/packages/ folder called X11User.pkg - run this package to install X11.

There are community builds of Universal Binary OpenOffice.org for Intel based Macs; however the PPC versions will run in Rosetta anyway and are QA'd which the Intel builds are not at the time of writing. Once X11 is installed on the machine downloading and installing OpenOffice is like any other MAC application.

Go to the Openoffice.org web site and follow the instructions to download the application. Once this has finished, double click the "OOo_2.0.1_MacOSX_install_en-US.dmg" or ("OOo_2.0.3rc3_MacOSXIntel_en-US.dmg") package and then drag the OpenOffice.org Icon to your applications folder.

When the copying process has finished you can click the eject button in the finder and the dmg package can be deleted.

Click the OpenOffice.org icon to run the application, optionally register and you're ready to go.

Solaris

 * Instructions for installing OpenOffice.org in Solaris?

for now, see http://wiki.services.openoffice.org/wiki/Documentation/Administration_Guide/Solaris

Others

 * Instructions for installing OpenOffice.org in other operating systems?

title: OpenOffice.org/Installation


text:
Using GNOME/Login

When you turn on your computer, you see the operating system load. Once the system has started, the computer will open the GNOME user interface. GNOME runs atop the operating system and provides a Graphical User Interface (GUI) for the user to interact with. The login screen is the first screen a user will see when GNOME starts.

Types of login screen
There are two types of login screen, standard and graphical. GNOME allows the users to select a login theme to customize their computer. Different operating systems provide different “preferred” graphical themes.

A graphical login screen includes a “face browser”, which lets the user visually select their user name, while a standard login screen simply provides text boxes to enter a user name and password. There is no OK button on the login screen; instead, you press Enter once you have entered your password. If you entered your password correctly, GNOME will display the main desktop.

Shutting down the computer
But suppose you want to shut down your computer instead. There is a way to do this from the login screen.

In the top-right corner of the login screen you will see two icons. We will be focused on the one with the power-button icon. (The person icon, if clicked, reveals a list of accessibility-related features, such as High Contrast or Mouse Keys.) A dropdown will appear. Confusingly, all you will see there is a button labeled “Dark Style” and another power-button icon. To shut down this computer, you must click the second icon to display the restart and power-off (shut down) commands. Clicking Suspend will put the computer to sleep.

title: Using GNOME/Login


text:
User talk:62.253.96.40

Hello, Welcome to Wikibooks. I noticed your addition of a Baklava recipe at Cookbook:Cuisine of Greece, and moved it to Cookbook:Baklava. I then noticed that the text was coppied verbatum from the link you provided at the bottom of the module, so I have listed the page as a possible copyright violation. If you are the copyright holder, could you please let us know, so that we may return the text of the recipe to the module.

Please note, even if this recipe was posted improperly, we still want all of your own original contributions, don't feel that your additions are not wanted, because they are.

Thank you, Gentgeen 22:59, 8 May 2004 (UTC)

title: User talk:62.253.96.40


text:
Using GNOME/Installing

If you do not have GNOME installed on your system, then there are many ways to install it

With a Linux distribution
Many Linux distributions offer GNOME as part of their package selections. Please check the documentation of your distro to see if GNOME is an available desktop enviroment.

Distribution specific help

 * In Debian type "apt-get install gnome"
 * In Ubuntu type "apt-get install gnome gdm"
 * In Mandriva (formarly Mandrake Linux) select GNOME workstation from the installer.
 * In Gentoo type "emerge gnome"
 * In ArchLinux type "pacman -S gnome"
 * In FreeBSD type "pkg_add -r gnome2"
 * Installation on any distro will most likely require root access.

Garnome
Garnome is a script that lets you compile GNOME.

Live CD
If you want to try GNOME without installing, try a live CD that uses it such as Gnoppix, Gnome Morphix and Ubuntu Linux. If you want to easily compare GNOME and KDE, try a Fedora LiveCD - you can select which desktop to use at login time.

Other Operating systems
Sun Microsystems' Solaris offer GNOME BSD's can install it via ports or pkg-src. Just find the GNOME directory and type make install.

title: Using GNOME/Installing


text:
Using GNOME/File manager computer

The Computer icon is the gateway to accessing files outside your home folder. Using Computer, you can access files stored on CD-ROMS, Floppy Disks, USB keys and on your Network.

(need screenshot)

To Access it.
 * Select "Computer" on the desktop.
 * Choose "Computer" from the places menu.

title: Using GNOME/File manager computer


text:
Using GNOME/Accessibility

GNOME is designed for all users, including users with disabilities that make using a computer difficult.

This section will cover accessibility tools in GNOME.

title: Using GNOME/Accessibility


text:
Using GNOME/Other Jargon

Controls
"Controls" or "Widgets" are elements that make up the desktop and applications.

Dialogs
Dialogs are windows that ask you a question or provide information.

More Glossary

title: Using GNOME/Other Jargon


text:
Using GNOME/Icons

Icons are small pictures. There are many types of icons.

 * Menu icon
 * Action Buttons
 * Icons on Buttons
 * Launcher icons

title: Using GNOME/Icons


text:
Introduction to Philosophy/What is Epistemology

The word 'epistemology' comes to us from ancient Greek: the noun episteme meaning 'knowledge' and the suffix -ology meaning 'the science of' or 'the study of.' So, literally speaking, epistemology is the study or investigation of knowledge itself. It is also often referred to as Theory of Knowledge. Epistemic knowledge is not about what we know, but about what it means to know.

Epistemology seeks to answer basic questions about how human beings perceive the world and gain knowledge about it. The more prominent of these include:
 * 1) Is there an external world?  How can we be certain?
 * 2) How does memory work?  How can we know that our memories are genuine?
 * 3) What is the nature of perception?  To what extent does current knowledge affect future perception?
 * 4) What knowledge is inherent to humans and what is learned after birth?  Can new facts be assimilated without innate concepts?
 * 5) To what extent are inferences based on perceptions valid?  What is the proper way to make such inferences?

It is helpful to note the basic (Socratic) distinction made between beliefs, which hold to opinions, and knowledge, which holds to 'truth'. Knowledge concerns apodictic facts that are absolute and simply cannot be false (while opinions can be and often are false). According to Karl Popper, the only way we can distinguish between truth and not-truth is by subjecting test-statements to experimental invalidation. Plato thought otherwise; he believed that truth is not subject to invalidation. So then the epistemological question: Where does our knowledge come from? And to take it further (as many philosophers have): What are the limits of human knowledge? Here one should read up on the two main competing philosophical branches of the early modern age: Rationalism and Empiricism. Rationalist thinkers like Descartes argue that all knowledge comes from reason, and everything in the world of homo cogitans is fundamentally rational. It is through the human mind that the human knows. Empiricists (at that point, the British thinkers: Berkeley, Hume, Locke) insist that most, if not all, *real* human knowledge can only be arrived at through human experience. It is through the human senses that the human knows.

There is also the theologically-driven idea of knowledge as (divine) revelation (think God, by his Spirit, giving to the writers the Holy Bible). There is an interesting blurring of the lines separating belief and knowledge here. St. Augustine gives us an eloquent discussion of reason vs. faith.

One issue that is of interest to many epistemologists is the analysis of knowledge, that is trying to find an answer to the question "what conditions need to be satisfied to say that someone knows something?" For a long time, the conditions seemed clear to most philosophers: to know something, you must believe it, it has to be true and you have to have a justification for believing it. The problems raised by the Gettier problem have reopened this question for many and a great number of new problems have arisen. This kind of question is considered the most general of questions in epistemology, while concerns about, say, the different ways of knowing are a much more specific set of questions within epistemology.


text:
Electronics/Component Identification

''We should make sure that types of markings for all the types of resistors, caps, ICs, and everything else are thoroughly explained. This is not terribly important to engineers, who are more concerned with theory and just pull them out of a labeled box. But to the hobbyist this is pretty important, and also difficult to learn, because there are so many nonintuitive ways to label things.''

''Should we put the color code and SMT numbering explanations at the top, and then tell in each section what they stand for? (ohms, picofarads, microhenries) "The color-digit pairs used in the resistor example below are standard, but the tolerance and higher multiplier values are for resistors only."''

Identifying resistors
Most axial resistors use a pattern of colored stripes to indicate resistance. SMT ones follow a numerical pattern. Cases are usually brown, blue, or green, though other colors are occasionally found like dark red or dark gray.

4-band axial resistors
Axial resistors are also called "thru-hole" resistors because they cross the plate to which they are welded. Four band identification is the most commonly used color coding scheme on all resistors. It consists of four colored bands that are painted around the body of the resistor. The values of the resistors belong to series. The best-known series with 4 rings is called the E12 serie because this series contains 12 values. The values are part of the preferred numbers. The scheme is simple: The first two numbers are the first two significant digits of the resistance value, the third is a multiplier, and the fourth is the tolerance of the value. Each color corresponds to a certain number, shown in the chart below. The tolerance for a 4-band resistor will be 2%, 5%, or 10%

For example, if you are looking for a 12K (12000 ohm) resistor with ±5% tolerance, you would be looking for a Brown (1) Red (2) Orange (×103) Gold (±5%) resistor.

12×103 ohm = 12000 Ω = 12 kΩ

Note that red to violet are the colors of the rainbow where red is low energy and violet is higher energy. Resistors use specific values, which are determined by their tolerance. These values repeat for every exponent, 6.8, 68, 680. This is useful because the digits, and hence the first two or three stripes, will always be similar patterns of colors, which you will learn to recognize without checking a chart. To help you remember them, the standard values for 10% resistors are:

The E24 series therefore contains 24 values with 2 significant digits. As soon as the E48 series, the resistors contain 3 significant digits, so a code with 5 color rings. These numbers are not chosen at random, but are part of IEC 60063. Charles Renard proposed these numbers and have since been adopted in the international standard ISO 3.

5-band axial resistors
5-band identification is used for higher precision (lower tolerance) resistors (1%, 0.5%, 0.25%, 0.1%), to notate the extra digit. The first three bands represent the significant digits, the fourth is the multiplier, and the fifth is the tolerance.

SMD/SMT resistors
SMD (surface mounted device) or SMT (surface mount technology; same thing) resistors are found mostly on devices where large scale integration is present. They generally use an alphanumeric numbering system.

For surface mount resistors, a numerical code is used. For 10% tolerance resistors, 3 numbers are used, for 1% resistors, 4 digits are used. The scheme is similar to color codes, in that the first two or three digits are the significant digits, and the last digit is the multiplier (expressed as an exponent of 10). This is easy to remember as "the first digits then as many zeros as the last digit after it" ohms. "683" for instance, represents 68 with three zeros after it: 68 000 = 68 kΩ. Likewise, "4991" represents 499 with 1 zero after it: 499 0 = 4.99 kΩ.

For small resistance values, an alternate notation is often used. For these, an R is used in place of the decimal. For example, 5R6 = 5.6 Ω.

They are the smallest class of discrete resistors available.

Large resistors
For large power resistors and potentiometers, the value is usually written out explicitly as "2Ω", for instance. Some power resistors have their power rating imprinted on the component body. An example of a 10W "2Ω" power resistor follows.

Examples

In the top example, the colors are brown (1) - black (0) - orange (×103) - gold (5%). This means 1 0 ×103 Ω ± 5% = 10 ± 0.5 kΩ. This resistor has a value anywhere from 9.5 to 10.5 kΩ

The second example has 5 stripes. They are brown (1) - black (0) - black (0) - red (×102) - brown (1%). This means 1 0 0 ×102 Ω ± 1% = 10 ± 0.1 kΩ. This resistor then has a value anywhere from 9.9 to 10.1 kΩ.

Note that these are both 10 kΩ.

The third example is a larger power resistor, and is labeled green (5) - blue (6) - black (×100) - gold (5%). This means 5 6 ×100 Ω ± 5% = 56 ± 2.8 Ω. This resistor then has a value anywhere from 53.2 to 58.8 Ω. It has a higher power rating than the others, which is not labeled, but is obvious from its larger size.

Electrolytic capacitors
Axial electrolytic capacitors are electrolytic capacitors that have connections on both ends. These are most frequently used in devices where there is no space for vertically mounted capacitors. See photograph above.

The arrowed stripe indicates the polarity, with the arrows pointing towards the negative pin. Warning: connecting electrolytic capacitors in reverse polarity can easily damage or destroy the capacitor. Most large electrolytic capacitors have the voltage, capacitance, temperature ratings, and company name written on them without having any special color coding schemes. Most electrolytic capacitors in general have light blue, black, dark purple or brown colors, although some specialized ones come in yellow and other colors. If for some reason you are uncertain about the polarity, the can is always the negative connection. Most axial caps have both ends visible. The positive end has a rubber insulation and the negative side is only aluminium.

Radial electrolytic capacitors are like axial electrolytic ones, except both pins come out the same end. Usually that end (the "bottom end") is mounted flat against the PCB and the capacitor rises perpendicular to the PCB it is mounted on. This type of capacitor probably accounts for at least 70% of capacitors in consumer electronics (that don't use SMT components). See photograph above.

Like their axial counterparts, many radial electrolytic capacitors have the voltage, capacitance, temperature ratings, polarity, and company name directly written on them without having any special color coding schemes.

Tantalum capacitors
Tantalum capacitors are useful due to their low leakage current, reliability, and their ability to keep stable capacitance over a wide range of temperatures. below is a diagram:

They have special markings. The stripe on the side indicates polarity. Usually with a store bought component, the longer lead is positive. Warning: connecting tantalum capacitors in reverse polarity can easily damage or destroy the capacitor. Generally it will have the capacitance written in µF, and the working voltage below it. In some cases (often when µF is not printed), the value (in pF) is encoded with three numbers; the first two digits being the significant figures, with the third being the multiplier (i.e. number of zeros). Tantalum capacitors are most commonly dipped and have a shiny coating, as well as vary in color, being yellow, red, and sometimes blue. Most axial tantalum capacitors look completely different.

The dark line on the SMT variety is the positive terminal. The dipped axial through-hole variety will be marked with a + or a dark line to indicate the positive terminal.

Ceramic capacitors
Ceramic capacitors are generally non-polarized and almost as common as radial electrolytic capacitors.

Generally, they use an alphanumeric marking system. The number part is the same as for SMT resistors, except that the value represented is in pF. They may also be written out directly, for instance, 2n2 = 2.2 nF. For capacitors the tolerance code is:

letters with * are not used consistently.

how similar is this to resistors?

For example, .047K = .047 µF 10%.

The dielectric material is sometimes designated by another code: (note: the materials in the table below are not ceramic capacitors as implied, but plastic and paper)

Please note that the table above is valid most of the time but not always because it is not a real standard. To be real sure you may check the data sheet from the manufacturer in mind.

The cap color can also indicate the dielectric:

Axial ceramic capacitors
These often have a yellow body, and use the same color band system as resistors, except that the value indicated is in pF.

Multilayer Ceramic capacitors

These usually use the same alphanumeric system.

SMD/SMT capacitors
These are often not even labeled. If they are labeled, it is the same system as SMT resistors, but representing pF. Polarized capacitors are marked with a stripe on the positive end of the package, though some electrolytic SMT capacitors are marked on the negative end of the package. They are rectangular, and often black or tan colored. The black capacitors are easily mistaken for diodes due to the white stripe on one end...

Inductors
Sometimes the value of an inductor is printed directly on it. If no units are given, µH can be assumed. If it looks like the system used by SMT resistors, it is probably that system, except that the value represented is in µH. Inductors as a class of components are current and magnetic sensitive devices. Inductors work by creating a magnetic field around the windings. The current of a electron flow causes energy to transfer into the field. Similarly, if there is a no current but a field present, coiled wiring responds by creating a current in the wiring. This is the original source of the name Inductor, it induces a current when exposed to a field, or a field when exposed to a current.

Axial inductors
If an inductor uses the color code system, the value represented is in µH. Expect to see a wide silver or gold band before the normal colored bands, and a thin tolerance band at the end. but have some more information that is not given. Identified on PCB assemblies with the letter designation of L, the last letter in the word coil.

Examples
Diode:- in electronics a diode is a two terminal electronic component with asymmetric transfer characteristic, with low (ideally zero) resistance to current flow in one direction, and high (ideally infinite) resistance in the other.

title: Electronics/Component Identification


text:
File:Diborane formation.png

Formation of Diborane

title: File:Diborane formation.png


text:
User:Bulbaboy~enwikibooks

'''Note: There is an ongoing issue with users attempting to get Bar Ilan University blocked from editing, while impersonating me. I will not be editing from another account  (unless I don't want to be identified as Bulbaboy in the first place) , or vandalizing, and I am also in America, while Bar Ilan is (I believe) in Israel.'''

Hello, I originally registered for the English Wikipedia under the username Bulbaboy, and then decided to make a Wikibooks account, so I could edit non-anonymously over here too. Since I'll probably be on Wikipedia more, why don't you check out my Wikipedia userpage - I'm likely to put more stuff there than here.

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title: User:Bulbaboy~enwikibooks


text:
General Mechanics/Index Notation

Summation convention
If we label the axes as 1,2, and 3 we can write the dot product as a sum

 * $$\mathbf{u} \cdot \mathbf{v} = \sum_{i=1}^3 u_i v_i $$

If we number the elements of a matrix similarly,

 * $$\mathbf{A}=

\begin{pmatrix}A_{11} & A_{12} & A_{13}\\ A_{21} & A_{22} & A_{23} \\A_{31} & A_{32} & A_{33} \end{pmatrix} \quad \mathbf{B}= \begin{pmatrix} B_{11} & B_{12} & B_{13}\\ B_{21} & B_{22} & B_{23} \\B_{31} & B_{32} & B_{33} \end{pmatrix}$$

we can write similar expressions for matrix multiplications

 * $$(\mathbf{A} \mathbf{u})_i=\sum_{j=1}^3 A_{ij} u_j \quad

(\mathbf{A} \mathbf{B})_{ik}=\sum_{j=1}^3 A_{ij} B_{jk}$$

Notice that in each case we are summing over the repeated index. Since this is so common, it is now conventional to omit the summation sign.

Instead we simply write
 * $$\mathbf{u} \cdot \mathbf{v} = u_i v_i \quad

(\mathbf{A} \mathbf{u})_i= A_{ij} u_j \quad (\mathbf{A} \mathbf{B})_{ik}= A_{ij} B_{jk}$$

We can then also number the unit vectors, êi, and write

 * $$\mathbf{u}=u_i \hat{\mathbf{e}}_i $$

which can be convenient in a rotating coordinate system.

Kronecker delta
The Kronecker delta is

 * $$\delta_{ij}=

\left\{ \begin{matrix} 1 & i=j\\ 0 & i\ne j \end{matrix} \right. $$

This is the standard way of writing the identity matrix.

Levi-Civita (Alternating) symbol
Another useful quantity can be defined by

 * $$\epsilon_{ijk}=

\left\{ \begin{matrix} 1 & (i,j,k)= (1,2,3) \mbox{ or } (2,3,1) \mbox{ or } (3,1,2) \\ -1 & (i,j,k)= (2,1,3) \mbox{ or } (3,2,1) \mbox{ or } (1,3,2) \\ 0 & \mbox{ otherwise } \end{matrix} \right. $$

With this definition it turns out that

 * $$\mathbf{u} \times \mathbf{v} = \epsilon_{ijk} \hat{\mathbf{e}}_i u_j v_k

$$

and

 * $$\epsilon_{ijk}\epsilon_{ipq}=

\delta_{jp}\delta_{kq}-\delta_{jq}\delta_{kp} \,$$

This will let us write many formulae more compactly.

title: General Mechanics/Index Notation