Do most readers skip the prologue?

Question: The prologue of my story is extremely important as it adds context to what is happening in the first chapter. While talking to my friend, they revealed to me that most readers skip the prologue. Now I'm not sure what to do, as I wouldn't like for the reader to skip it as they may be confused about what's going on in the story.
Comment: There might be a few readers out there who do... but in general, no.
Comment: I would guess that most readers don't skip the prologue, but skip the *preface*. Maybe your friend confused the two concepts? Unfortunately, I don't think there are any reliable data available regarding which reader skips what.
Answer: I conducted an informal survey of writers in my writing classes and determined that anywhere between 2/10 and 4/10 readers skip over the prologue the first time they read a novel. My instructors were aghast at the response. But that is because every one of the instructors love books and are published authors.
There is also unscientific data gleaned from online discussion sites, that between 30%-40% of readers skip the prologue. I used to be one of those people.  Now I read the prologue.
If the content of your prologue is important to understanding your novel then make it the first chapter of your book. If you find that it doesn't read as well, then ask yourself how much of the information in the prologue is needed for the first pages of your novel to work. Let's pretend the reader needs to know the first four pages of your prologue to find Chapter 1 thrilling and interesting. You can move those first four pages into the start of Chapter 1. They become your first scene. It doesn't matter if they have a different POV or  have characters that don't continue on. You start your story where it needs to start.
For example, in the Diamond Age by Neal Stephenson. The entire first chapter is effectively a prologue. You get a sense of the world through the eyes of a no-good-nik who dies on the final page. The second chapter starts years later and sets the story in motion.
Comment: Writing class at what level? Is it something that kids are forced to take in school or is everyone there because they're passionate about reading/writing? For me, I wouldn't even *think* to skip the prologue if I was reading for pleasure, but I might if I was in school and that wasn't on the test.
Comment: @Laurel, the UCLA Writer's Program
Answer: There is no data on how many readers skip prologues. But from feedback and discussions among readers we can assume a few things:
What few readers dislike

Novel without prologue
Story with one single protagonist
Story told from one single point of view
Minimal worldbuilding and background provided during the storytelling and only when and as much as it is necessary
Story told in third person past tense
Minimal descriptions of characters and locations
Standard Written English

What many readers dislike

Novel with prologue
Story with multiple protagonist or an ensemble cast
Story told from multiple points of view
Extensive worldbuilding and background inserted as nested stories or embedded narratives
Story told in first person present tense
Detailed descriptions of characters and places
Dialogue or narrative in dialect or slang or historical variants of English

There are genre or market segment conventions that deviate from this general tendency. For example, in Young Adult fiction first person present tense is more common nowadays that third person past tense, and in epic fantasy readers seem to enjoy stories told from the viewpoints of multiple protagonists and characters telling longwinded background stories around the campfire.
But in general, the more your story tends towards "what many readers dislike", the higher the likelihood that your story will disappoint its audience and get bad reviews. The numbers given by editors, agents, and professional authors for how many readers acutally skip the prologue vary between "most", "50%" and "some", but even if only a very small number of readers dislike prologues, those are the readers you will invariably disappoint. On the other hand, 0% of readers will be disappointed because a book has no prologue.
That doesn't mean that you shouldn't do what I listed under "what many readers dislike", just that you should be aware of conventions (especially in your genre) and make sure you only deviate from those conventions because it greatly enhances your story.

Personally, I tend to skip prologues, as I have found that they are largely irrelevant to the later story. Most prologues have protagonists that don't appear later in the story or only as background information or side characters, and usually I can easily infer the information I have missed by what is told in the main story.
And if your prologue contains relevant information that I cannot infer, of if the protagonists of the prologue are part of the main cast of the main story, why not make the prologue your first chapter?

Given what little information you provide regarding your own story, I cannot recommend what you should do.
But there is one thing you definitely need to keep in mind: When your story has a prologue, you have to hook your readers twice – at the beginning of the prologue and at the beginning of the first chapter. Because when your readers finish the prologue and start with the main story, the switch in setting, protagonist, and topic will require an effort on the part of the readers. They have to motivate themselves to become interested in this other story.
Basically what a prologue does is mislead the reader. The reader becomes invested in the story laid out in the prologue (or they wouldn't keep reading it), they identify with the characters, they want to know how the story plays out. Then you stop telling that story and face them with another one: another protagonist with different goals that the reader, coming from the prologue, doesn't at first care about.
And here you have to pick up the reader and take them into the new storyline. If you fail at hooking the reader again after you have "misled" them with the prologue, the reader will put down your book at the beginning of the first chapter and stop reading.
Answer: The problem with most prologues is that they are a history lesson; not a story.
History lessons are boring. Most readers hate the history lesson, and the history lesson breaks the cardinal rule of writing for entertainment: It is telling, not showing.
The history lesson is filled with facts to memorize, but readers do not memorize facts! When people read for entertainment, they want to build an imaginary world in their head, a movie they are seeing as you describe what is happening. That requires settings, and a point-of-view character they are following in each scene, the reader wants to occupy that POV, see what they see, feel what they feel, as if they are, in spirit, part of the story.
Your job as a writer is to assist the reader's imagination, to build up the scenes and make their imagination match, in the important details, your own.
As a rule of thumb; readers are very poor at memorizing or remembering cold facts. What they remember is what we humans are good at remembering, the things we actually experience. The people we spend time with, or the people or other entities or things that threaten us.
Prologues tend to be far too much "telling", facts and situations that the reader must memorize for the story to make sense. And they fail, because they read for entertainment, and memorizing the prologue isn't fun so they skip through it, looking for a scene.
Instead of a prologue, you can start with a story, and immersion.
In the first Harry Potter book, JKR faces a cold open: The audience knows nothing about her world or anything in it. So she opens with strange happenings in the normal world, mysterious magical things going on, to establish that this story has magic, and is about this infant "Harry Potter" that survived something or other and that is a mystery, and his parents died, and he's being left an orphan. That is all the "prologue" we get, but told in story form, with characters, imagery, and dialogue.
Then ten years are skipped. The boring ten years of Harry growing up. Then magic things start happening again.
Do not start with a prologue. Start with a story. Start cold.
Readers will give you plenty of credit in the first 10% of the book, they fully expect to not know anything or anyone, and they expect to be introduced to the hero and the world in the first 10%.
That is why, in the three act structure most common for writing, the first 10% of the novel is devoted to our hero, in their normal world (no matter how fantastical it may be), going about their normal business, meeting any important other characters (which introduces them to the reader), etc.
Avoid the prologue; it must be disguised as story.
Don't worry about dropping your reader into the cold shallow end of the pool. They expect to be dunked that way. And they expect to get used to it.
Don't explain what is going on first; at worst you can do an opening half page explanation. The opening crawl in the first Star Wars movie, explaining the situation we are about to see, is 83 words long. About a third of a page in novel.
But then, we are in action! A frikkin' huge Imperial Star Destroyer is in pursuit of a tiny Blockade Runner and is going to catch it; a "droid" is given a secret message by a strange woman and told to get it to yet another unknown man. None of this explained, all we know is that this is all incredibly urgent, they are in bad trouble and desperate, the big bully is the bad guy, the little Runner are the good guys, and now everything is riding on this trash can looking droid R2-D2. (And for the rebels, outmatched in every respect except their wits and courage, this is their normal world.)
Here we are, dunked in the cold shallow end, but we are enthralled. This is what we expect from stories, be they movies or novels.
Ditch the prologue. Start with a story. Start with a scene that introduces your characters in their normal world. That should be the first 15% of your novel. About then, something happens (the inciting incident) that intrudes upon this normality; and eventually forces your Main Character (or Crew) out of their normal world.
What you consider "Chapter 1" is probably Chapter 3 or 4, the beginning of Act II. About 25% of the way through the whole story.
The term "Show Don't Tell" originated in stage plays; the admonition for playwrights was to not TELL the audience that, say, Mike is a heavy smoker, but to SHOW that, by having Mike always have a cigarette burning in his mouth, or hand. Don't say Margaret is overly sensitive, show Margaret being overly sensitive.
The same thing applies to print. Yes, everything is obviously "told", but the difference is in the reader's imagination. You are there to assist it, in creating a scene, and again you don't say Mike is a heavy smoker, you just show in every scene that Mike is smoking.
The problem with prologues is they are not stories, they are Telling. Not Showing. And Telling doesn't work, the readers won't memorize or remember what you have told them, because all they remember is the scenes that you Showed them, i.e. helped them to imagine and be present in. The sights, the sounds, the odors, how the temperature and humidity made them feel, the emotions they felt there.
Stories (Movies and Novels) are composed of sensory scenes.

Do most readers skip the prologue?


Pressure in deodorant can

Question: Pressure in a deodorant can is greater than the surrounding pressure but still the can is in equilibrium with the surrounding . Why does this happen. If we apply $F = PA$ then $P_{in}A= P_{atm}A$ and since both the areas are equal then both pressures must also be equal.
Please explain
Answer: A deodorant can contains a liquid hydrocarbon, typically a propane/butane mixture, and the pressure inside the can is due to the vapour pressure of this hydrocarbon. The pressure can be set to any desired value by varying the composition of the propellant - more propane makes a higher pressure while more butane makes a lower pressure. For a deodorant the pressures are typically in the range 1 - 3 atmospheres.
As long as there is liquid propellant left in the can the pressure will stay roughly constant, because as you spray material out the can some of the liquid evaporates to keep the pressure constant.
In your question you say:

the can is in equilibrium with the surrounding

but this is not the case. Liquid propellant is not in equilibrium at room temperature and a pressure of one atmosphere. That's why as soon as you lower the pressure in the can (by spraying from it) the propellant starts evaporating. The can is able to keep the propellant in a non-equilibrium state because it is rigid.
Answer: Think of an inflated balloon. Pressure inside the balloon is greater than atmospheric pressure. Entire system is in mechanical equilibrium because of tension provided by balloon surface. If you keep inflating the balloon, pressure inside the balloon keeps increasing, and so does tension in balloon surface, until it can take no more and bursts, thus equalising pressure. If the deodorant can does not burst, it is because the can wall is strong enough to tolerate the stresses generated by difference in pressure between inside and outside of can. So $P_{in}A=P_{atm}A$ is incorrect, because we have not taken into account forces due to can walls.

Pressure in deodorant can


MDI Application minimize/restore issue

Question: Ok, so I have a VB .Net MDI Forms Application.
frmMain is the "parent" form with IsMDIContainer set to TRUE.
I load "frmChild" from frmMain setting the MDIparent property to frmMain.
I minimize the form, then minimize the application.
I restore the application a few minutes later, then restore frmChild and find that frmChild is now totally blank...?
This happens intermittently when I minimize the child form, then minimize the application and subsequently restore the application then restore the child form...
Answer: I'm not sure what you are asking, but if you want to try and alleviate the problem you can try invalidating 'frmChild' which will force it and all it's contained controls to be redrawn.

MDI Application minimize/restore issue


How to say "you are welcome"?

Question: If someone thanks me in Latin, how should I respond?
I have been taught to reply sodes, but L&S does not seem to mention such use at all.
Did the Romans have any idiom for replying to "thank you"?
A direct translation of the English "you are welcome" is unlikely to work, and I don't want anything as heavy as gratias tibi ago, quod gratias mihi egisti.
Is sodes fine, but only a modern option?
Comment: *nihil est* 'it's nothing'
Comment: @Anonym That could work! Have you actually seen or heard it in use? I haven't, but that just proves my limited experience. If you can give a source for that option (your own experience is a source, too!), then I invite you to write that as an answer.
Answer: This is not a phrase which demands a response, at least not from the available evidence. Most instances of gratias ago do not have the thanked person respond at all, and I could only really find one exception.
In Cicero's De Oratore 2.268, we get this exchange:

Arguta etiam significatio est, cum parva re et saepe verbo res obscura et latens inlustratur; ut, cum C. Fabricio P. Cornelius, homo, ut existimabatur, avarus et furax, sed egregie fortis et bonus imperator, gratias ageret, quod se homo inimicus consulem fecisset, bello praesertim magno et gravi "nihil est, quod mihi gratias agas," inquit "si malui compilari quam venire".
There is also frequently acuteness shown, when something obscure and not commonly known is illustrated by a slight circumstance, and often by a single word; as when Publius Cornelius, a man, as was suspected, of a covetous and rapacious disposition, but of great courage and an able commander, thanked Caius Fabricius for having, though he was his enemy, made him consul, especially during a difficult and important war, You have no reason to thank me, returned Fabricius, if I had rather be pillaged than sold for a slave.

It's not a simple nihil est, but I think it gets the point across. But in this exchange, the thanked one minimized the actions, as if there actually was no reason to be thanked to begin with. This is different from the de nadas and de riens that essentially mean, "It wasn't very difficult to do, but I appreciate the thanks anyway."
In Terence's Phormio, we get this exchange:

Nausistrata: Phormio, at ego ecastor posthac tibi quod potero, quae voles faciamque et dicam.Phormio: Benigne dici'. Na.: Pol meritumst tuom.
Nausistrata: Phormio, I by Castor henceforth I will do and speak for you whatever I can, whatever you wish. Phormio: Thanks! (Lit. You speak kindly.) Na. By Pollux, you earned it.

Here it might help to recognize that there were different ways of thanking someone, and this comes after kind words. I imagine it being similar to the English response, "You're too kind!" It's not really the formal thanks and it's not really an automatic "you're welcome."
There might be others, but there's certainly nothing consistent. Searching all possibilities is time consuming, but I think it speaks volumes that it's not something that is easily found (unlike the many ways of thanking someone); despite giving several ways of saying "Thanks!", Goodwin Beach's article "De Sermone Cotidiano" doesn't mention "You're welcome" in any way, though it might help remembering that you're welcome in its current form as a response to thank you was first attested only in 1907.1
I searched for gratias and benigne both, and while responses are often given, there isn't anything on par with English you're welcome, French de rien, or German bitte.
For modern speakers, I indeed have heard nihil est, libet, precare/precamini, and flocci all used, though you should always keep in mind just what you're being thanked for and its appropriate response. Even in English, for someone being publicly thanked for the service to the state, "you're welcome" is hardly appropriate.
1: Though certainly there were other responses, they just weren't "you're welcome."
Comment: @RayButterworth I think you're reading that "no problem" too literally. I can guarantee that the majority are *not* thinking that deeply into their word choice. Just like no one is actually wishing "god be with ye!" when they say "good-bye."
Comment: @RayButterworth Interestingly, I've actually read that before. I'm no stranger to bristling at new lingo, though I try to keep myself grounded: all languages change. I like the note that "you're welcome" itself only dates to the 20th century. It probably also would have been rude to someone who came of age in the late 19th century, let alone their parents!
Comment: Only Americans say "you're welcome".
Comment: @fdb And not all of us. It's also situational, but I think the younger crowd is largely abandoning the term.
Comment: @cmw says "*the younger crowd is largely abandoning the term*", and using something far worse. I've stopped saying "thanks" to waiters, etc., because the "No problem" response is so annoying. I thank them to recognize them as people and show appreciation that they are there doing something I wouldn't want to do; but It never even occurred to me that my expecting them to do the job they are paid for could have been a problem. "No problem" should be reserved for when one has gone out of their way to do something that they were under no obligation to do (e.g. push a stranger's car stuck in snow).
Comment: @cmw, yes, I realize that to the speaker it means the same thing, but for people of my generation, it's still annoying. (We'll all die off soon, so it really will become no problem :-).  See [All Things Linguistic](https://allthingslinguistic.com/post/124189121619/no-problem-vs-youre-welcome), where one person hears it as I do, and another responds with the opposite view.
Answer: In @cmw's answer we see an exchange of the following kind:

A thanks B for a compliment or a display of esteem/affection
B replies with Meritum est tuum, maybe embellished with a preceding interjecton like pol

I propose a general formula to cover (all?) other cases, provided a reply is appropriate in the first place:

A thanks B for some kind of help or advice
B replies with Gaudeo quod tibi profuerim or Gaudeo me tibi profuisse "Glad I was helpful (to you)"

There don't seem to be instances of these phrases in classical sources, but a quick Google search shows that numerous Latin grammar books have reported them from early 19th century on, so I would use them casually.
Answer: SAW THIS ON QUORA:
John Kerpan, Master of Latin and the Classical Humanities
Answered 3 years ago · Author has 1.4K answers and 1.7M answer views
If you want to reply to "Thank you" like a Roman, use "libenter". It means "willingly" or "gladly".
Comment: Thanks for sharing that answer. Can you provide a link to the response on Quora? It can help to have that in the event there's further discussion or information from the original source.
Comment: @Adam Traupman, in his dictionary under "Welcome", lists *libenter* as meaning "you are welcome".

How to say "you are welcome"?


Modern page button label displaying commands

Question: is they anyone facing issue the modern page all the buttons seem to be in programming language :
CommandBar_NewPage instead of NewPage
Answer: Does this issue happen in all modern pages? Or just in one page?
What does the button look like before(when did you find this issue)? Do they display normally before?
Try to open this modern page in another browser and compare the results.
It seems that somebody had edited the page. Check if somebody ever rename the label.


Making Ubuntu programs available to fedora through "chroot"

Question: I have Fedora and Ubuntu installed on different partitions on my system. Now i want to make programs such as "adobe reader" or "kerio-control-vpnclient-8.4.2-2869-linux" available to fedora. those programs are installed on my Ubuntu system. I want to know how can i make those programs available to Fedora with the help of chroot or other similar commands(like LXC).
Comment: Why don't you just install them under Fedora? Libraries and binaries might be incompatible ...
Answer: chroot will not solve your problem at all.
In fact, chroot will make you run this program as if you were in Ubuntu itself and not in Fedora. You will need a complicated setup to make them access your file system outside chroot. chroot is meant more for isolation.
One good solution for your problem however is just to use environment variables.
Maybe a small bash script that sets your path to Ubuntu location and also changes LD_LIBRARY_PATH might work.
For example, something like:
#!/bin/bash
export PATH=PATH_TO_UBUNTU_BIN:$PATH
export LD_LIBRARY_PATH=PATH_TO_UBUNTU_LIB:$LD_LIBRARY_PATH
acroread

where PATH_TO_UBUNTU_BIN and PATH_TO_UBUNTU_LIB should be the paths to your ubuntu bin (like /bin and /usr/local/bin or wherever your acroread resides) and PATH_TO_UBUNTU_LIB is the path to Ubuntu shared libraries directory (like /lib or /lib64).
Comment: chroot does help, because a lot of programs look for files at fixed locations. `PATH` and `LD_LIBRARY_PATH` doesn't do everything. Schroot provides the "complicated setup" (in fact not so complicated) to make the rest of the filesystem accessible in the chroot.
Comment: Thanks Gilles for the precious info. I didn't know about schroot before. I was thinking along the lines of chroot only, where he will have to somehow figure a setup so that he can access his original system, which would require maybe some directories or symlinks in his Ubuntu installation. And these might appear to be broken whenever he boots into Ubuntu. That's what I thought, but thanks for your info :)
Answer: Install schroot on your Fedora system. Schroot is a wrapper around chroot that allows non-root users to use predefined chroots and arranges for home directories, /proc, etc. to be present in the chroot.
I wrote a schroot guide in How do I run 32-bit programs on a 64-bit Debian/Ubuntu? With a Fedora host system, the setup is mostly the same — it's mostly the distribution in the chroot that needs to be tweaked. Install the debootstrap package to install Ubuntu in the chroot.
To invoke a program in the chroot from outside, you need to invoke schroot. You can use a shell wrapper like this for a chroot called trusty:
#!/bin/sh
exec schroot -c trusty -p -q -- "${0##*/}" "$@"

Make symbolic links to this script with the names of the programs you want to invoke. For example, if this script is located at /usr/local/bin/trusty, and you want the acroread command to invoke the program in the trusty chroot, make a symbolic link
ln -s trusty /usr/local/bin/acroread


How do I calculate the compressive strength of a wall?

Question: I literally just have a thin steel wall that stands vertically with a load on top. The thin edges of the wall are oriented vertically with the load applied on top of the top thin edge, with the large planar faces of the wall facing horizontally to the sides. I thought there would be an easy calculation based on height, length, thickness (width) and a material parameter for the steel I'm using, but internet searches have yielded me no useful information as to the specific scenario I'm looking for. Is it not that simple to calculate wall strength based on a top loaded compressive force oriented vertically downward onto the height of the wall? Someone please help!
Comment: The key word you are looking for is [buckling](https://en.wikipedia.org/wiki/Buckling).  Note that if your thin wall isn't supported on the vertical edges than the section on [plate buckling](https://en.wikipedia.org/wiki/Buckling#Plate_Buckling) won't help, because your boundary conditions are totally different.  Your wall will probably buckle pretty much like a 2-D column.
Comment: The thing is, the wall shouldn't be designed so the thin panel carries any compressive load at all, except its own weight. There should be a frame round it to carry the loads.
Comment: The Wallis supported at the bottom, and it is not an actual wall of a building. Think of a piece of sheet metal standing on its edge. Imagine the bottom is completely fixed and can't move. I need to know how much force can be applied to the top of it before it would buckle or start to irreversibly compress.
Comment: It will buckle , the compressive strength has nothing to do with it.
Answer: The analysis of your wall depends on many factors, is it supported at all sides or just the top and bottom or may be it is acting as a cantilever.
Also whether the supports are clamped or pinned.
As a very conservative start you can use $$ P_{Critical}= \frac{\pi^2EI}{(KL)^2}  $$
K is the effective length factor and ranges from 2 for cantilever to 0.5 for fixed/fixed ends.
Roark's Formulas for Stress and Strain by WARREN C. YOUNG
RICHARD G. BUDYNAS 7th edition has formulas on plate buckling on chapter 15, pp 715 to 730.
Comment: The slightest amount of geometrical imperfection, or loads that are not perfectly vertical, makes this not "conservative" at all. If I was going to spend any time near it, I would apply a safety factor of at least 100.
Comment: @alephzero, I am not sure! the formula I used is the Euler's buckling load for columns, a plate has much more stability, so much so that engineers even don't use Euler's for flat or curved plates. However it gives a lower limit estimate. if the OP clarifies his configuration of the wall we can compare the results between plate formulas ad Euler's.


Do all cameras with autofocus need motors?

Question: Do all autofocus cameras need motors to drive the lens? I would have thought today's modern electronics rendered motors obsolete.
Comment: I'm unclear if the question is "are AF motors needed to AF a lens" or if the question is something like "why don't we have mag-lev based AF"?
Comment: Yet another possible sense of the question is if the motor has to be in the camera, which i think is the case with some Nikon's. Most DSLR and mirrorless do not have a motor in the body, but the lens will do.
Comment: Maybe see [Is the lack of AF Motor on the Nikon D5100 an important factor?](http://photo.stackexchange.com/questions/17093/is-the-lack-of-af-motor-on-the-nikon-d5100-an-important-factor) and [What is an auto-focus motor?](http://photo.stackexchange.com/questions/20327/what-is-an-auto-focus-motor)
Comment: Is the question really "Do the __camera__ need a motor for AF-lenses to work?" ?
Comment: Simon - Did you mean (1)  "For cameras where the lens elements are moved to achieve AF ..." **OR** (2) can AF be achieved with no lens element movement? Most answered (2). I answered mainly (1)
Answer: There are several good answers and relevant comments already.
 I'll address a possibly ambiguous point.
You said  - "Do all autofocus cameras need motors to drive the lens?"
 Others have explained that a "Light field" or Plenoptic camera (Wikipedia) does not need to move the lens at all to alter focus, so does not need focus motors as nothing moves.
However, you also said " ... I would have thought today's modern electronics rendered motors obsolete."
You may have meant that perhaps some thing other than a motor may be used to move the lens elements in some modern cameras.
 Loosely speaking, anything that provides mechanical movement can be regarded as being a motor. By that definition, if anything moves mechanically then a motor must be involved.
However, there are various means by which movement can be achieved with a "motor" that is different or very different from traditional ones. Not all of these are (yet) used in camera lenses.
A common motor which is included inside lenses is the SSM or USM = Supersonic Motor or Ultrasonic motor.This Wikipedia article gives a good description. An ultrasonic motor is often a subset of piezoelectric motors which use electrical constriction or expansion of a crystal ti impart movement. Wikipedia noites -

An ultrasonic motor is a type of electric motor powered by the ultrasonic vibration of a component, the stator, placed against another component, the rotor or slider depending on the scheme of operation (rotation or linear translation).
Ultrasonic motors differ from piezoelectric actuators in several ways, though both typically use some form of piezoelectric material, most often lead zirconate titanate and occasionally lithium niobate or other single-crystal materials.
The most obvious difference is the use of resonance to amplify the vibration of the stator in contact with the rotor in ultrasonic motors. Ultrasonic motors also offer arbitrarily large rotation or sliding distances, while piezoelectric actuators are limited by the static strain that may be induced in the piezoelectric element.

It is not essential to use piezoelectric action to produce an SSM / USM but this is usual.
Animated demonstration of SSM / USM
Superb short flash animations of piezo actuators in action
.
 This is the Minolta  CCD antishake piezo actuator system at work rather than focus drive but demoinstrates the basic principals superbly.

Related patents here and here
Comment: +1; good point. And now I'm imagining a steampunk camera with litle pneumatic actuators for moving the lens elements....
Answer: Traditionally lens elements must be moved in order to change the focus, as you must alter the path light takes through the lens, thus a motor is required to move the glass. However this will not always be the case.
Lytro recently produced the worlds first commercial light field camera. The idea is that this camera captures not only the intensity of the incoming light but a measure of the incident angle of different rays. This allows the effect of different focus settings to be calculated mathematically enabling you to "refocus" an image long after it was captured, using a computer. No motors or moving parts are necessary.
Comment: +1 The state of the art, though, means that "light field" cameras require a huge number of sensels (data points) compared to the size of the final image and outboard processing (in fact, a Kodachrome-style single-provider processing API at the moment) to do the recalculation. That's likely to change over the near future (see the Nokia PureView and increasingly powerful low-voltage mobile processors), but we're still at the "not ready for prime time" stage today (and there aren't a lot of early adopters to drive the necessary R&D, so who knows what the future holds).
Answer: Other than Light Field cameras, movement for autofocus is needed. Some cameras have motors but many do not. The smaller Nikon, like D3100 do not have a motor for example. Instead, there is a motor in each lens. The bigger Nikon, like D4, have motor but also work with lenses having a motor.
So, it is not absolutely needed but is normally needed either in the camera or in the lens. The Light Field camera I have never seen but read that it is very restricted and actually has a focus motor because there is a limit to the possible focus change from Light Field.
Comment: A theoretical light field camera wouldn't have that limit, but the real-world Lytro models today don't gather enough data.
Answer: You always need some means to move the lens, but it may not be a motor
in a traditional sense. For example, you can reshape a
liquid lens
by applying a voltage across it, with no moving parts except the liquid.
Answer: It is also possible that some micro cameras like those on cellphones or integrated webcams use electromagnetic focusing. This is the method used to focus some CD/DVD drive lenses, where part of the elements are mounted in such way that different voltage applied to a number of coils cause movement of the focusing element.
I Have seen this mechanism in action and in some cases they have a wide motion range compared to the size of the elements. The size of a typical CD optic pickup is rather bigger than the lenses found in cellphones.
From an electric design point of view, these mechanisms are more similar to a solenoid than to a motor.


Are there advantages to disable Touch drive?

Question: In the new game Asphalt 9 there is an option to enable or disable Touch Drive. What the option basically does is steer for you. Turning it off gives you more control oveer the steering oveer the car. But frrom what I have experienced so far, is that the auto-steering is working quite nice, and I don't miss any items/corners. So why do I want to turn it off anyway? Are there any advantages turning it off?
Comment: If a racing game is steering for you, are you even playing it?
Comment: it's more fun imo, and you get bragging rights.  Also, I imagine it will allow you to excel more and pull off some really good stunts if that interests you.  More control equals more possibilities.
Answer: When it comes to making a jump in the hunted mode, the Auto Driver misses the ramps and crashes into the police barricade.
Comment: I always have enough time to decide. Time moves even slower at those points it seems, so this has not been an issue. I never missed one with touch drive.
Answer: Touch Drive can be useful in many ways, including:

Allows you to go around corners faster
Gaining more control over the vehicle

The only downside is that it might be difficult to work with. Therefore it is suggested for you to turn it off and drive all by yourself.


Modulating Output of a Pulley with Variable Inputs

Question: I am working on a recreational project to take variable inputs and convert them to a constant output without substantially altering the force required to achieve such a task. The best way to visualize the problem is with the classic case of using a simple pulley to raise a bucket of water. I am wondering if there is a mechanism that would allow someone to pull the rope variable distances ( 1ft, 2 ft, 3ft, 4 ft, etc) all while lifting the bucket to the same height each time (1 ft). Ideally, it would not take any more or less force to perform the task. From my understanding of gears, increasing the distance of the input would decrease the force required to raise the bucket. I am wondering if there is a known mechanism or way to offset this in order to make the input force requirement relatively constant or if there is potentially a better way to accomplish the task? Thank you for your help! My knowledge of engineering is rudimentary at best and was wondering if something like this is even physically possible.
Comment: (1) "*... to pull on one end of the pulley at variable distances*". I think we need a diagram. Usually we pull on the rope, not the pulley. (Search for "block and tackle" images.) (2) To lift a load a fixed amount will require $energy = mgh$ where $m$ is mass (kg), $g$ is gravity (10 m/s/s approx.) and $h$ is height (m). (3) By using gears, levers, hydraulics or pulleys you can reduce the **force** but you will have to increase the **distance** the force acts over to do the same amount of work. (4) Can you [edit] to explain the real problem you are trying to solve.
Comment: To make the input relatively constant, add a lot of friction to your pulley. To make the distance traveled limited to a fixed value, add a mechanical stop and have the load on a limited slip connection to the line and have lots of extra line beyond that point
Answer: What if you wanted to be able to pull only 1 inch and lift the bucket the same 1 foot? You needed to pull the rope with a force 12 times the weight of the bucket.
The pulley or a lever or a crane all they do is change the mechanical advantage. They can not and never will change the amount of work needed.
Work, energy are nonvariant fundamental concepts.
If you need more mechanical advantage you end up increasing the travel distance of a smaller force. and vice versa.
Answer:
Figure 1. Your drawing shows four identical systems. Pulling a rope down by a certain distance will cause each of the loads to move up by the same distance.

Figure 2. To get mechanical advantage you need to use a block and tackle system.
This gives a mechanical advantage equal to an integral multiple of the pulling force. Note that the mechanical advantage is equal to the number of ropes supporting the load because the load weight is spread between the supporting ropes. In the case of the 1:2 setup there are two vertical ropes supporting 100 N so each takes 50 N.
Answer: Work = force x distance.
You want the amount of force to be constant, regardless of the distance that the user will pull the rope.  So the amount of work the user does is variable.  But the work done on the bucket in lifting it 1ft remains constant.  This is a rather strange requirement.
The only way I can see that would work is to change the mechanical advantage (see the answer by Transistor), but then deliberately add or remove friction.  So if the user sets the system to 1:4, then you add a load of friction so that it's just as hard to pull the rope as it was at 1:1.


Am I making the stray cat uncomfortable with my touch?

Question: Around a week ago, a stray cat transferred her kittens to my backyard. Since then I've been like feeding her max 4-5 biscuits (since my parents don't want her to grow too attached) and I just go stare at them for a while in the afternoons. When she's with her kittens, I've been allowed to be within a palm length, then she'd hiss (I accidentally came close while drying clothes), but she doesn't mind if I come close when she's alone. Today, I went close after sitting directly beside her for a while and stroked her head with a finger a couple of times. She kept her eyes closed, but didn't hiss or anything, nor did she try to evade (I was near the door while she had ample open space to run away). Is she too tired and is thus not reacting, or is she okay with it?
Answer: Closing her eyes is an indication the cat trusts you.
When a cat is feeling wary of its surroundings, its natural instinct is to stay alert. A cat will only relax enough to close its eyes or sleep if it feels safe enough to. Cats even communicate a certain level of friendliness by using body language that indicates its feeling relaxed and secure in its surroundings despite, or maybe because of, your presence. Closing its eyes, slowly blinking as if it's drowsy, assuming a vulnerable position such as lying in its back are some of the ways a cat expresses it is relaxed and trusts you.
It's likely she still hisses at you when with her kittens because she is still extra protective of them, which of course is perfectly natural. At the same time, she still allows you to come quite close to them before she warns you to stay away.
Comment: Thanks for answering! She sits on her belly with her hind legs partially tucked in. I wanted to ask one more thing: I've read it somewhere just now that directly looking into their eyes is considered aggression, but damn, that's what I've been doing while whispering "hello" and grinning like an idiot when I open the doors and sit. For a minute or two she'll stare then she's probably uninterested. Did I come off as weird?
Comment: Looking directly into a cat's eyes is aggressive, but if she doesn't show any signs of being intimidated, she probably is not. It's sort of similar to how a person can glare at another person, and some will be intimidated by it, while others will not.


Can't find the right SD card slot

Question: I just got a Raspberry Pi B+ with a NOOBS SD card, but I can't find the SD card slot. I found the micro SD slot on the bottom of the Pi, but my SD card won't fit. Where do I connect it?
Answer: The solution was that it was a micro SD card in an SD card adapter, but it looked like a normal SD card.
Answer: RPi B+ uses micro SD card so I think you need to use a micro SD card and either clone the data from your existing NOOBS or download the latest one into that micro SD card.
Comment: Maybe it got packaged wrong, because the NOOBS card came in the same package as the Pi but it isn't a micro USB card.
Answer: look at the end of the noobs card there shuld be a smaller card you can pull out

Can't find the right SD card slot


What's a good iOS app for quickly posting screenshots on the web?

Question: Something analogous to photobucket for the desktop - whose iPhone app is a bit useless to me because it doesn't enable importing from the camera roll. I'm looking for something that easily allows me to share a screenshot (to embed somewhere, for example in a forum, or on a Stack Exchange question) but don't want to junk up my flickr, Instagram, etc.
Answer: There's also the official Flickr app. It supports uploading photos and videos from the Camera Roll. Flickr specifically will require that you already have an account on the service, most Twitter integrated networks (yFrog, TwitPic) will "create" an account when you use it for the first time.
Flickr the site.
Flickr.app the iOS app.
(Native to iPhone only, obviously works on the iPad using small screen emulation.)
Answer: If you don't want to "junk up" your flickr or instagram or whatever, you could just create another flickr or twitter account only for screenshots. Then you could use these specialized account settings in Flickit or Photoshop Express or whatever.
You could also use Dropbox. I love it for syncing files, and it easily works with images too.
Comment: Dropbox's Public Image Gallery is a pretty good idea. It's a bit indirect given how one uses the Dropbox iOS app, but a good idea nonetheless.
Answer: If you have twitter, Echofon uploads pics from the camera roll to Twitpic very quickly. Otherwise, the Flickr iOS app works very well, and you can select any pic/screenshot from your library to upload. Thanks, Hope that helps.
Comment: Sorry, I didn't see the last part of the question (I'm posting from an iPhone). Can I suggest imageshack? If you already have that and want to keep it clean, then sorry again, but if not, They do a free app from which you can upload from camera roll.
Comment: Ditto. And I generally agree with Alistair's followup suggestion.
Comment: As I said, I don't want to junk up my flickr, Instagram, etc. That goes for Twitter/Twitpic/whatever as well.
Answer: I like the ImgurFree app.  You can take a photo or import one from a Camera Roll.  It uploads the photo to imgur and creates a link that you can quickly copy the link in your clipboard or post directly to Reddit, or Email it.  Works great for me. It also keeps a history of all the images uploaded using the phone which you can quickly delete from Imgur site if you want.


How to blur text in a video using windows 7?

Question: If I have screen recording videos containing text that I want to blur or censor out, how can I do that in Windows 7?
Answer: The answer to your question is that it is not possible to blur footage with the default set of Windows 7 apps. 'Windows Movie Maker' used to be the go to free software for basic editing but it's now only downloadable from Microsoft and isn't actually 'free' for all intensive purposes.
Your solution is here:
Download 'Shotcut' video editor for free here.
Follow the instructional video on how to blur parts of an image using Shotcut Here
Comment: Please quote the essential parts of the answer from the reference link(s), as the answer can become invalid if the linked page(s) change.
Answer: It does not matter, that you are running Windows 7.
What you need is a video editing program.
For blurring, pixellation and basic censoring, you do not necessarily need expensive software such as Sony Vegas.
Free software such as OpenShot (originally for Linux, but also available for Windows) could also do your job.Alternatviely, you can download and burn a DVD with Ubuntu Studio, and boot from that DVD. Some video editing software, including KDEnlive is pre-installed out of the box.


Multi master single slave replication mysql

Question: I have a scenario in which there are two masters master 1 and master 2 and i want to add slave to master 2 , so when i update in master 1 it will replicate for master 2 so how do i get slave of master 2 to update form it ? What is the  parameter to be set for it?
Answer: I am assuming you already have Master1 and Master2 acting as Slaves of each other?
The slave will be replicating from only one of the Masters.  It will get data from the other Master via that one.  But you need (and probably already have):
<code>log_slave_updates = ON  -- on all 3 servers
server_id -- distinct values for all 3 machines
</code>


What is the math behind the smartphone fish eye lenses

Question: I found out information that these add-on fish eye lenses for smartphones have a focal length of about 2mm. I bought a lens and tried it with several different phones and it worked. I found out that these phones have different focal lengths (3.85mm and 5mm). My question is what is the mathematic behind this optical combination (fish eye lens + phone lens).
These are my calculations:
$\frac{1}{f}=\frac{1}{d_o}+\frac{1}{d_i}$; I assume that distance between both lenses is 1mm. The image of the fish eye lens is the object for the second lens so:
$\frac{1}{4}=\frac{1}{-1}+\frac{1}{d_i}$, or $d_i=0.8\rm{mm}$.
So the focal point of the total system has changed from 4mm (without fish eye lens) to 0.8mm. Am I wrong?
Answer: It is not quite this simple. The assumption you made is that the image of the fish eye lens is always on the focal point of the lens. This is only true for an object that is infinitely far away. In reality, the location of the image of the fish eye lens will depend on the distance the object is away from the fish eye lens.
In practice, however, the object you are taking a picture of is likely to be at a distance $d\gg 2\rm{mm}$ away, and your math is a good approximation. You should keep in mind however that in general two lens systems cannot be simplified as a single lens with one focal point.
Comment: Thank you very much for your comment! Indeed, the objects I have in mind are at least 10 meters away, so I thought that would be enough to approximate with the focal length. I am quite green with the lens system calculations and this is why I try to understand things deeper.


Is there an API or programmatic way to convert ".htaccess" rewrites to "web.config" IIS Rewrites?

Question: I know I can do it in IIS Manager, but I am looking for some programmatic way to do it. We need to do this for customer all the time.  So it would be great if there's a programmatic way of doing so.
Answer: There isn't a reliable programmatic way to automatically convert .htaccess files to web.config files because IIS's configuration is quite different from Apache's, as well as their configuration file formats.
There are some sites which claim to do automatic conversions, but the scope and accuracy of these are questionable.
You can however suggest that your client add an IIS module that uses standard regular expressions, since Apache's mod_rewrite module uses Perl Compatible Regular Expression vocabulary - see:  Apache - mod_rewrite-Regular Expressions
One such module is ISAPI_Rewrite, which is written in pure C/C++. From their FAQ's:

ISAPI_Rewrite is a rule-based rewriting tool to rewrite requested URLs
  on the fly. ISAPI_Rewrite uses regular expression rules. With regular
  expressions you don't need to write a thousands check strings. The
  comparison and replace of URLs can be done with a few string patterns.

Using regular expressions for IIS should help to greatly speedup conversions of Apache RewriteRule's.
Comment: How bout sites like cbsa.com.br/tools/online-convert-htaccess-to-web-config.aspx and htaccesstowebconfig.com? I wonder how they do it.
Comment: I'd suggest testing the output of these before thinking about _how_ they do it, or using them...


I make an action editor animation using keyframes, I save and quit, then when I open it back up, my animations are gone

Question: I am making an animation using Action Editor and key frames, I then go to save and quit, when I go back in, most of my animations are gone and only a few remain.
Answer: Any action that is not assigned to an object is automatically deleted by the garbage collector after a certain amount of time.
To prevent any of your unused actions from disappearing, use the Fake User feature (shield icon) to permanently keep the certain action in your blend-file's data memory.


Can molecules rotate on any axis?

Question: In statistical physics, the rotation of molecules in a gas can be excited if the temperature is high enough. This rotation is excited in a quantum mechanical way. But is the axis of rotation also quantized? Could a molecule of $N_2$ rotate around any axis when excited?
Answer: That depends on the molecule and its symmetries. For example, a molecule of an ideal monoatomic gas cannot rotate because it is spherically symmetric. A typical diatomic gas molecule, like $N_2$ could rotate about two axes because it is axisymmetric so it cannot rotate about its axis of symmetry. A more complicated gas molecule, like water vapor, can rotate about all three axes since it is not symmetric at all.
Note that rotation about three axes does not imply anything about quantization of the axes since any direction is a vector sum of three axes. However, the amount of energy in a rotational degree of freedom is quantized and thus corresponds to a specific wavelength, just as with energy in any other degree of freedom.

Can molecules rotate on any axis?


Must you have an uncompleted destination card in Ticket to Ride?

Question: Put another way, once you complete the destinations on your initial destination cards, do you have to draw a new destination card or can you play without having an uncompleted destination?
Answer: Drawing Destination cards later in the game is optional - the only time you have to draw Destination cards is at the start of the game.
If you finish all of yours early enough then it may be worth drawing more, but if you finish them later in the game it would be unproductive to draw more, and your efforts are better spent trying to block other players.
Since Destination cards are always kept secret from other players until scoring, any rule that did say you had to have incomplete Destination cards would be based entirely on trust.
Comment: It's not always unproductive to draw more destination cards late in the game.  Sometimes you can get lucky and draw one (or more) that you already have covered by your existing trains on the board; netting you extra points "for free".  It's a gamble though.


Integral solutions to $a_1 \cdot a_2 \cdots a_k = N$

Question: How many integral solutions are possible for the equation $a_1 \cdot a_2 \cdots   a_k = N$ where each of $a_1,a_2,\ldots,a_k $ satisfy the property $ 0 ≤ a_i ≤ 9 $?
Comment: Look at the prime factorization of $N$. It should be of the form $2^{r_2}3^{r_3}5^{r_5}7^{r_7}$ (no solution exists if there are other prime factors). All $5$s and $7$s should be present among $a_i$ as themselves, so there are $\binom{k}{r_5} \binom{k-r_5}{r_7}$ ways to do it (again, solution doesn't exist if $k > r_5+r_7$). So, the problem now reduces to number of solutions of $a_1 a_2 \ldots a_r = 2^{r_2}3^{r_3}$, where $r=k - r_5 - r_7$.
Answer: First, you need to factor $N$ as $N=p_1^{r_1}\cdot...\cdot p_k^{r_k}$ where $p_i$ are distinct primes. Observe that $a_1\cdot...\cdot a_n=N$ if and only if $a_i=p_1^{r^{(i)}_1}\cdot...\cdot p_k^{r^{(i)}_k}$ with $\sum_{i=1}^n r^{(i)}_j=r_j$. So your problem is equivalent to writing each $r_i$ as a sum of non-negative integers.
Clearly, your condition on $a_j$ makes it impossible for any $N>9n$ or any $N$ with primes bigger than $7$ in it's factorization.


IE8 not saving cookie values?

Question: I'm having some problems with IE8 respecting a cookie I'm setting via the jQuery cookie plugin.  Things are working fine in Firefox, Chrome, Safari, IE6 and IE7 (via IETester), but IE8 just doesn't seem to be storing the cookie.
If I F12 to the dev toolbar and check the cookies from the "Cache" menu item, I can see my cookie after I set it.  I also see other cookies being set but I only have my test page as my home page.  I have a bunch of cookies for microsoft and coolwebdeveloper.com (I pulled that site up and don't remember ever going there)???
Below is the cookie I'm setting/verifying through the dev toolbar.
<code>NAME  filters
VALUE  show
DOMAIN  mydomain.com
PATH  /my/neat/path/
EXPIRES  3/12/2011 6:30:02 PM
</code>
When I quit/relaunch IE8, that cookie doesn't persist (it's set to expire 31 days out).
Anyone have any ideas?  Is there some preference setting I can check? Could this be some IT setting/firewall thing I can't do anything about?
I did try options -> privacy -->lower the internet zone to "accept all cookies" but that didn't make a difference.  I do have a little highlighted note at the bottom of the screen "some settings are managed by your system administrator", though.
Also, in View -> Webpage Privacy Policy, the domain I'm testing under says "no cookies were restricted or blocked".
Answer: In internet Options under browsing history uncheck the "Delete browsing history on exit", which is checked by default.  This not only deletes the history but also deletes cookies.

IE8 not saving cookie values?


Bouncing Truth level

Question: In VVVVVV, how can I beat the level with the two TRUTH words bouncing up and down? They are perfectly opposite each other's bounce, and the platform to run on disappears too quickly.
Answer: To get past this level, it is all about timing.
As to when to run?

Start running just before the "TRUTH" on the left touches the spikes from its ascend, and keep holding the right button until you are underneath the second truth. By then, it should be just touching the spikes from an ascend. Flip and keep running til' you get into the nook on the other side.
If you are going a little faster than the two "TRUTH" and keep running into the second "TRUTH", take a short pause underneath the first "TRUTH" to give the second "TRUTH" time to head back up.

 Just a warning, let go of the right button just before you reach the wall, otherwise you'll just 'walk' into the spikes on the other side.

Bouncing Truth level


Why did a newspaper edit out, rather than obscure, women from a photo?

Question: When the Israeli newspaper HaMevaser published a photo of world leaders at the Paris Unity Rally, it edited out the women from the photo, so they were entirely absent from the result.  The explanations I've seen for this is that men aren't allowed to look at immodestly dressed women.  My question is: was there a religiously based reason for not just putting black bars over the exposed skin (and perhaps hair) that was considered immodest, or was the reason purely one of aesthetics?
Answer: You'd have to ask the editors of the newspaper to understand their reasoning, so this answer is just my own thoughts of possible factors involved in the decision.
Aesthetics is one possible reason.
Other possible reasons that spring to mind are that the newspaper doesn't approve of the idea of men and women together, or of female leadership in general. Blurring out the women would make it obvious that there are still women in the photo.
One last reason is that however bad the backlash was with them edited it out of the photo completely, it would have been even worse if the women were merely blurred or blackened out. Then anyone picking up the newspaper would realise women were actually at the march. At least now you have to find the original photo online to realise that people are missing from the picture.


18 month keeps her eyes closed when she meets new people

Question: My daughter is very attached to my wife. She's good with me (dad) and was okay with her grandparents. But lately she cries when she meets new people and keeps her eyes closed for hours. She either cries or sucks her thumb and needs to be attached to her mom. We thought she was pretending to sleep when she first exhibited this behavior. We are a little worried because she will walk towards her mom with her eyes closed and has run into things. Any ideas of what may be wrong?
Comment: Have you ever heard of the "highly sensitive child"?
Answer: She is probably very shy or sensitive. Most young kids when shy, go to the person they are most comfortable with, in this case your wife. Keeping her eyes closed is a way of not being able to see other people, especially if they are strangers and she is not comfortable looking or being around them. Therefore she closes her eyes and goes straight to her mother :).
Nothing is wrong with being shy, she just needs some time to learn how to start openinging up and being more confident with strangers.
Comment: I'm afraid this can be a problem in the long run, since I was a kid Im always shy and afraid of people, just like the girl described on the post. My mom was always worried and all but my dad always said "don't worry he will change when he grows up". Now Im already 16 and yet, I still have problems communicating and socializing
Answer: I may be wrong, but I'm thinking your little one was born during the pandemic when even her birth was very isolated. Unlike those before her who had dad in the delivery room and all the grandparents, aunts and uncles waiting to meet her, her entrance was very sterile and she was not exposed to a lot of family members and friends of family. My granddaughter just turned 2 and she hid her face when anyone other than mom, dad and her big brother was around. As the restrictions have loosened and she is more exposed to a somewhat normal social life, she is more comfortable around new faces. Not that she approaches strangers or even welcomes strangers, but she no longer pulls a hoodie over her face or sits in a safe spot with her head down and her eyes closed. Children also get their cues from mom and dad and the vibe they give. Your sweet girl seems perfectly normal at her age. If she was 18 years, you may receive different answers. ♥
Answer: Separation anxiety or nervousness around new people is very normal at her age, and indicates that she has a healthy attachment with her primary caregivers! Meeting new people can be overwhelming for many toddlers and even older children (and adults!), and closing her eyes may be one way she can control her environment. Some children are more sensitive than others. My son is 3 years old and will sometimes cover his ears briefly or turn away when meeting new people. He will usually warm up and eventually be quite social if I don't push him to interact with the newcomers, if I am friendly to them, and if we meet in a place where he is comfortable.
Answer:
keeps her eyes closed for hours

Seriously? Hours? That sounds super worrisome and not normal behavior for an average shy child. An average shy child would cry, avoid eye contact (yes, close eyes according to "If I cannot see you, you cannot see me"), turn away, run to a trusted person, hide behind that person etc.
As a parent, it is easy to fall into the trap that you want to encourage your child in that moment, when the visitor is in the house, to be less shy. But that just makes it worse. You cannot teach someone to swim while they are drowning.
Instead, provide the comfort that your daughter needs, calm her, tell the visitors, preferably before the visit, not to physically approach the daughter unless she approaches them even if that is disappointing for them. Take her out of the room if need be or to a safe distance. Engage the visitors in something else than your daughter. When daughter is calm again, you could walk by the visitors, daughter in your arms, in order to get something from that room, while the visitors do not even look at the child. Then walk out again. Repeat. Eventually visitors can try a low-key peekaboo. Or daughter can accept sitting in your lap at a safe distance from the visitors. Yes, this is not much fun for you and your visitors but neither is a scared child.
Maybe meeting visitors outside and go for a walk (to a playground?) is more acceptable for her?
Your equivalent to a "swimming lesson" would be to try to engage in conversation with people in shops, neighborhood, playground or similar with the goal that (1) your daughter remains calm even when looked at, (2) can be encouraged to wave to the stranger or similar.
Background: My youngest son turned super-shy with strangers (but not for hours!) at exactly the age of 6 months, as if he had read the book of child development, and that stayed for years. Fighting it would only turn into frustration for everybody. But, on a positive note, there is no way such a child would walk off with a stranger!


What's a liquid layout?

Question: My designer keeps throwing out the term "liquid" layout. What does this mean?
Thanks for the clarification, I have always just called this a percentage layout, and thought he was saying that the pieces could be moved around, and that was liquid
Answer: A "liquid" layout is a site layout that expands to fill the entire available area as the browser window is resized. Typically this is done using CSS. Liquid layouts can be quite helpful for certain types of sites, but they also tend to be significantly more effort than fixed width layouts, and their usefulness depends on the site content and how well implemented they are.
Comment: Pedantry: 'A "liquid" layout is a site layout that stretches or contracts horizontally, relative to the browser window's width'. I think it's important to make the point that it's *width* that's relevant, and it doesn't *have* to completely fill the available area.
Answer: From http://www.maxdesign.com.au/presentation/liquid/ :

All containers on the page have their
  widths defined in percents - meaning
  that they are completely based on the
  viewport rather than the initial
  containing block. A liquid layout will
  move in and out when you resize your
  browser window.
Answer: Basically, it's a layout of a web page that doesn't rely on a specific width specifications for elements in the page.
See the discussion over at Wikipedia.
Answer: It means a layout which adjusts dynamically to the browser (or whatever client) width and height, to make efficient use of all available screen space, as opposed to (mostly) fixed width layouts which are made to fit a common denominator resolution at that particular time (e.g. 800x600 used to be the norm for websites for many years).
Answer: See this:
http://www.time-tripper.com/uipatterns/Liquid_Layout
Comment: Good link, but the site has been migrated to http://designinginterfaces.com/Liquid_Layout
Answer: Liquid Layouts refer to the design concept of a website. A liquid layout will move in and out when you resize your browser window, due to is having percentages and relative widths in the CSS.
Answer: It just means that it will contract/expand to fill the browser's window size (usually the width), up to a certain point if things are done well. Otherwise text can get quite hard to read on big (24"+) monitors.
Answer: One of two:

The design will scale to the width of the browser (as in, if the browser was 1024px wide, the design will be as well)... although this does get quite fun when designing for 100px wide browsers (sometime designers will actually set a min-width though).
The design has a fixed width, but is set in a measurement using a relative size... for example "em"... so as the font size is increased, the width of the page increases.
Answer: A liquid layout is a method of CSS layout that defines all widths in percentages, so the areas of the page will grow/shrink when the viewport (browser window) is resized.
They're very useful if trying to create a site that will fit both large and small screens. They're a little more difficult to work it than fixed layouts, because you're relinquishing some level control over how everything fits in the page, and you have to pay very close attention to your content, to make sure it doesn't fall apart aesthetically on resize.
I would say liquid layouts are most useful for text heavy sites with a fairly basic column layout. You might also find a happy medium with an 'elastic' layout -- one that has both liquid and fixed areas.
Answer: In a true Liquid layout, your content expands and contracts to fit your user's browser window in a meaningful, calculated and intelligent way. So it's more than just setting your column and container widths to percentages.
Done well, this can result in a increase of perceived quality. Done poorly, it's a usability nightmare.
Going Liquid is a huge pain the rump. The pain is worth it though if the topic/client/product(s) you are building the site for have a strong visual quality to them (think summer blockbuster film site), require a certain fit and finish, or if it needs to display large chunks of data.
Note: I'll update this a bit later with links to good examples and citations for my claims

What's a liquid layout?


Battery state of charge for 48 V battery with Ardunio?

Question: Is it possible to monitor the battery SOC for a 48 V battery with an Arduino?
If not, which device would you suggest?
If the battery is at 85% SoC, it should be re-charged, triggered by a relay.
Comment: What kind of 48V battery you mean? Also do you mean with Arduino alone, or with Arduino and some extra components such as battery coulomb counting IC? Which Arduino you mean? There must be dozens of different things called Arduino, some being more suitable and some being less suitable for anything. How accurate your SoC measurements must be? How much capacity the battery has?
Comment: @Justme The 48V battery bank consists of actually 8 6V deep cell batteries with each 140 amp hour rating. The capacity should be expanded from time to time.
I mean the Arudino Uno Rev3. The SOC measurements should be very accurate.
Comment: Batteries of what chemistry? How much is "very accurate" to you and in which units?
Comment: Batteries are Power Sonic Model PS-6100 F1. I don't know how to define the accuracy of the SoC, but it should be reliable
Comment: So they are standard AGM VRLA batteries. Unfortunately that model is 7.3Ah to 12Ah capacity, not 140Ah, so something does not add up.
Comment: Yes, I do have now this ones, but I want to switch to oldtimer batteries 140 Ah.
The battery SoC schould be flexible. If a Arduino can not do this job, then it's ok to me, but I need a device which can do. Thanks.
Comment: The point isn't if an Arduino or some other MCU can do the job or not. The point is what other circuitry the Arduino or any other MCU needs around it to do the job of measuring VRLA state of charge according to some specification that does not seem to exist. So no, an Arduino or any other MCU alone can't do that and they all need the same circuitry around them so if it is an Arduino or something else is irrelevant
Comment: Ok, what else do you need?
Answer: If charge voltage and current suffices, then pretty much any microcontroller with access to sufficiently accurate ADCs will suffice.
Use resistive dividers to reduce voltage to levels compatible with the ADC, and low side shunt ideally with differential ADC (or dedicated current monitor) for dis/charge monitoring.
For completeness, add a remote temperature sensor.
LiPo/Liion is more complex, as voltage monitoring may not be sufficient for long term stability, and you may need coloumb counting.
Answer: Yes, it is. You would take a voltage divider to get the current voltage down to a range that the arduino's ADC can observe ("Arduino" doesn't actually mean any specific hardware, but all different implementations of the Arduino platform have some sort of ADC).
Depending on the battery chemistry and speed of charging, you'll also want to track the current that flows into the battery. How you do that depends on the currents and what you use to control these currents – it might be as simple as a shunt resistor and two ADC channels, or as complex as getting current estimates from an integrated switch-mode controller.
Generally, Arduino is really not the type of platform you'd want for that. There's ready-made charger control ICs for most battery types.
Answer:

simulate this circuit – Schematic created using CircuitLab
simply you can use this
Comment: Your question about this circuit indicates you have problems with it. Why it can simply be used here?
Comment: this just repeats two answers that had already been given and doesn't contribute something new in its current form! Please expand your answer why this particular voltage divider, and what problem it solves specifically. This page does *not* strive to be a collection of uncommented schematics, but a collection of knowledge helping people understand what they're trying to build!


briggs stratton 16 hp ic single cylinder

Question: I have a Lincoln welder with a 16 hp briggs Stratton engine that will only run with the choke closed. what could cause this?
Comment: Welcome to Motor Vehicle Maintenance & Repair! Have you done any troubleshooting on it yet? Is this a new or used system? I would guess (off-hand) that there may be some clog or air leakage (like from a cracked hose) in the carb. Have you checked the carb out at all?
Comment: It is an older machine I think 1970"s I replaced carb gasket which I believe was causing overheating after about 10 mins of welding ran good for a while I have looked other leaks sometimes easy to miss.
Comment: The main jet is partially clogged, time to disassemble the carb and clean out all the fuel passages. there is no such thing as a mechanic in a can, you just have to do as suggested.
Answer: This is most likely an issue with the carb having issues with ethanol clogging. You may be able to get it work by using something like SeaFoam thrown into the gas tank at a high concentrate. This may entail rebuilding the carb, but I've found it's usually worth my money to replace the carburetor directly due to the amount of time/effort it takes to get a rebuilt carb running correctly.
What is going on is the ports in the carb have become gunked up due to the ethanol. The reason it will run with the choke on is because there is a greater amount of vacuum draw on the ports, which gives the engine the gas it needs to run. Unfortunately, it usually runs too rich and doesn't run as fast as it should, which causes other issues (low generator output).


Why is the proton the only stable hadron?

Question: The title pretty much explains the question, but I've always thought that it'd be a neutron because of its 0 charge.
Comment: Because there is no other lighter baryon that proton can decay into. And the [baryon number](https://en.wikipedia.org/wiki/Baryon_number) is conserved in the standard model.
Comment: Baryonic number is not conserved by electroweak interactions in general due to quantum [chiral anomaly](https://en.wikipedia.org/wiki/Chiral_anomaly#An_example:_baryonic_charge_non-conservation). And [proton decay](https://en.wikipedia.org/wiki/Proton_decay) (into pions and positrons, say) was actively discussed and searched for experimentally, it is not ruled out even today despite the lack of experimental confirmation. So there can be no a priori reason why proton should be stable.
Comment: Are you asking why the neutron (in isolation) decays to a proton (plus electron and anti-neutrino) but not the other way around?
Comment: @Conifold Proton decay is theoretically impossible in the Standard Model and the "Standard Model" tag on the question implies that this is not a request for conceivable beyond the Standard Model theories that would differ from this theoretical prohibition. Sphaleron interactions can't give rise to proton decay.
Answer: Protons, neutrons and in general hadrons are in the quantum mechanical regime and are not elementary. Elementary are the quarks with their positive and negative charges. Here is the main quantum mechanical  image of a proton in rough lines

and here is a neutron

Again in rough lines, they are quantum mechanically bound by the potential with the additions of two fundamental forces, the strong QCD force, and the electromagnetic force. In quantum mechanics, as stated also in the comments, systems are stable when they are in the lowest energy state, and this state happens to be the proton.

The title pretty much explains the question, but I've always thought that it'd be a neutron because of its 0 charge.

The neutron "bag" contains two down quarks , and ends up heavier than the proton bag, which has two up, lighter than down , quarks, so the neutron is in a higher energy level than the proton. The picture is more complicated because of QCD , and the hadronic bags contain a large number of virtual gluon and quark antiquark pairs, as illustrated here for the proton, but qualitatively the argument of lowest energy level holds.

A lot of theoretical effort is expended in trying to calculate the mass of the proton in lattice QCD, where all the contributing potentials are taken into account,
Comment: Another key part of the puzzle is conservation of baryon number. The aggregate number of quarks in a system minus the aggregate number of anti-quarks in a system is conserved. So, a proton, which has three quarks more than the number of anti-quarks it has (on shell and virtual combined), can't decay into an end state that has, for example, four, two, one, or zero on shell quarks in it. The proton is not the lowest mass-energy hadron (that would be the pion at about 1/7th the rest mass of a proton), but it is the lowest mass-energy hadron with three quarks (which is a baryon number of 1).
Answer: the usual answer is that there is no lighter hadron state available into which it could possibly decay. according to this picture, the proton is absolutely stable i.e., if left alone, it lasts forever.


About Beurling algebras

Question: Do there exist an amenable Beurling algebra that is neither Arens regular nor strongly Arens irregular? In his memoir "The second duals of Beurling algebras", A. T. Lau proved that there exists a weight $\omega$ on $\mathbb Z$ such that $\ell^1(\mathbb Z,\omega)$ is neither Arens regular nor strongly Arens irregular, but this algebra is not amenable.
Answer: It seems to be underappreciated by too many authors (this remark is not directed at the OP, but based on my frustrating experiences in several conferences and reading several papers) that what the older results of Gronbaek and White imply is the following: if $A=L^1(G,\omega)$ is amenable then $G$ is amenable and the weight $\omega$ is equivalent to a trivial weight, which means that $A$ is isomorphic as a Banach algebra to $L^1(G)$ (and $G$ must be amenable).
In other words, amenable Beurling algebras are intrinsically uninteresting as Beurling algebras, because they are just amenable group algebras.
Since $\ell^1(G)$ is AR when $G$ is finite (for trivial reasons) while $L^1(G)$ is always SAI for $G$ infinite (I believe this is N. J. Young's result?) the answer to your original question is negative: no such Beurling algebra exists.
Comment: Of course there are plenty of amenable algebras that are neither AR nor SAI; just take athe direct sum of an amenable AR algebra with an amenable SAI algebra, for instance

About Beurling algebras


Weird fix no longer works for "Workflow.Targets(127,5): error : Compilation failed. Unable to load one or more of the requested types"

Question: We have an x86 VS2008 project for .Net 3.5 SP1 using Workflow Foundation. On some computers it will compile, but others fail with:
Workflow.Targets(127,5): error : Compilation failed. Unable to load one or more of the requested types. Retrieve the LoaderExceptions property for more information.
Google brings up many solutions to different situations that can result in this error, but the only one I've found which worked for us is this: swap the order of the two <Import Project... /> tags in the .csproj file. Why this works is a mystery but the change allowed the project to compile and work on the computers which it wouldn't before (though it also caused problems on one machine that never required the change).
Is there any information about this problem and this weird fix? Lately the "fix" has become unusable. The project had been on the shelf for about a year, and now if the project is compiled with the tags swapped we get a run-time error when the workflow is initialized:
Cannot initialize 'StateMachineWorkflowActivity' that does not define a valid 'InitialStateName' property
If compiled without the  tags swapped (using one of the machines that is capable of compiling it regardless of whether the tags are swapped), this run-time error no longer occurs and everything runs perfectly.
Google again brings up many solutions to different situations that can result in this runtime error, but I've not found one that works for us and solving the original problem so that we don't have to swap the tags in the first place feels like a better direction to be looking in. The project was being compiled successfully a year ago (with the tags swapped), so things that have changed since then would include later versions of the dot net framework being installed in addition to 3.5 SP1 - the computers have all had the dotnet updates applied (but some computers are newer than others so would have got them all together). The project isn't set up on enough machines for meaningful patterns to be observable, given the number of confounding variables. One machine that can build it is a x64 Win7 with VS2008 and VS2010 installed (updating its VS2008 RTM to VS2008 SP1 didn't change it), one machine that can't build it is an x86 WinXP first using MSBuild, then with VS2008 installed, then with both VS2008 and VS2010 installed. MSBuild was able to build it a year ago and can still build with the tags swapped.
There is a hotfix that patches a couple of situations that cause the compile-time "Compilation failed. Unable to load one or more of the requested types." problems, but while our project seemed to matched the description in kb2023579 the hotfix that replaces it did not help - one of the many solutions that did not work for us.
(We need to solve this because the build server is one of the machines it doesn't compile on)
Comment: Do you have an assembly that contains custom activities which might be in the GAC on some machines and not in the GAC on others?
Comment: The assembly that fails to build (unless the tags are swapped) contains custom activities, but isn't placed in the GAC. Looking in the GAC on both a machine that can build and one that can't confirms it hasn't been accidently registered either. This assembly is the only one in the solution using the workflow foundation.
Comment: That weird fix is the only thing that worked for me.  Thanks.
Answer: For this issue:
Cannot initialize 'StateMachineWorkflowActivity' that does not define a valid 'InitialStateName' property

Try to check your namespace in the XOML file
namespace MyAssembly.SomeNamepace
{
    class Foo{}
}

then your x:class attribute should be x:class="MyAssembly.SomeNamepace.Foo"


How can I replicate GTA V "Los Santos" Font/Text in Photoshop?

Question:
Click image for full size
I think it has a little gradient, gray line inside, and white outside, main color is light gray, font is SignPainter. Please help me out, I've been trying to figure it out how to make it exactly how it is.
Comment: If you can see pretty well what all the pieces of it are than what are you stuck on? Show us where you're at.
Comment: I guess not enough Photoshop skills, don't know how to properly do it,   how to add line inside and outside of the text.
Comment: If you can upload an image of what you have so far, that would be a huge help so that we can precisely suggest how to improve upon what you've tried so far
Answer: I replicated the effect decently with layer styles. It might have been done in Illustrator originally and my approach has some antialiasing problems (I guess it's all the grouping) (see the end of this post for a fix) but it should work all right for most situations.
My results:

Here's my approach step-by-step:
1. Type out your text and apply a small dark grey stroke and a subtle grey-to-white gradient to it.

2. Group the layer (Ctrl+G) and add a slightly thicker and slightly off-white stroke to that group.

3. More groups! This time group the group the you created in the previous step and add a drop shadow to the newest group.

Footnote: Obviously this doesn't look exactly like the picture you linked, but just tinker with the sliders and numbers till you're happy and you should be fine.
EDIT: So I found a way to at least mostly fix the antialiasing problems. Simply duplicate the actual text layer, disable the stroke of the new layer and put it below the original text layer. This will ease the edges to be more smooth.
Comment: I too have anti-aliasing problems, don't know where that might come from..
Comment: Glad to help! I've updated the answer with a solution to the antialiasing problem. If you find that it works for you please mark the answer as accepted.
Comment: Yes It did help to reduce the anti-aliasing problem. Thank you very much again!


How long does it take for spearmint leaves to regrow?

Question: I just took a bunch of spearmint leaves, so when will they grow back?
I did some research and a timeframe wasn't given.
Answer: First, the individual leaves will not grow back. The plant in its entirety will continue to grow, and new growth will appear, in various places:

At the tips of the existing stems, in pairs, effectively making the stems longer.
In the axils, i.e. where a leaf is connected to a stem. This will happen when the tip of a stem is cut off.
New shots from the roots will come up.

The overall growth rate will depend on environmental factors, like the season, temperatures, available water and nutrients.
How quickly a plant can regrow harvested leaf mass will depend on the previously mentioned factors and the percentage of lost leaves. A full bush will not be influenced by the loss of a few leaves, but the more is harvested, the less leaf mass will remain for photosynthesis and the more energy has to be drawn from the plant's reserves.
Conclusion:
A simple answer along the lines of "it will regrow in X days" is impossible.
Answer: In my experience, mint grows very fast, so I wouldn't worry too much unless you took off almost all its leaves.
A store-bought mint plant took 3-4 weeks to roughly double in size with regular watering and moderate shade.
Comment: but how long does it take to grow?


Do we need any driver to connect microphone to laptop or android phone using xlr to usb connector?

Question: Do we need any driver to connect microphone to laptop or android phone using xlr to usb connector?
Comment: Brand and model of the adapter? Computer operating system?
Comment: What happens when you plug it in?
Answer: Normally, for laptop we don't need any drivers, which likes usb-mouse is a standard  USB subclass device. which subclass is "audio". The OS has it's driver already.
for Android device, Android is based Linux kernel, it can works fine in kernel level, but because this device is seldom use to Android Phone, if it is supported based your Android OS version and vendor.
after Android 5.0, Android device support USB audio standardly (Android support for USB audio class). before Android 5.0 your Phone Vendor can also enable supported for USB audio.
PS: I'm an linux/android developer.


Convert a column value like "June 11, 2020" into an actual date so I can filter on it relative to TODAY

Question: I want a column to list the upcoming dates for a meeting that I am manually entering into the drop down list. However, I want one of my views to only show the meetings that have passed. I tried to filter on column value < TODAY but the column value (is a string that happens to be a date) is defined as a multiple choice list so I can define which days the meeting occurs. Is there a way to either convert a value like "June 11, 2020" to an actual date value so I can compare it to TODAY? Or is there a way to have a date pull the options from a defined list?
Answer: Figured it out. I was able to use the DATEVALUE function to convert the text string to a date where I then can compare it to values like [TODAY]


Gmail and free third party GPG/PGP services

Question: I signed up for a free PGP key provider that worked with my Gmail account. I set it up to work with Apple Mail in Mac OS X Lion. Now, I realize I never use this encryption key, and I want to remove the service from my Gmail account setup. How can I find out what it is the service that I signed up for called, and how to remove it from my account?
Answer: Hard to guess what you might be using, and until that is known removing it is tricky. Two possibilities to try work out what it is:

Check your Google authorisations - Have a look at the application listed here, particularly anything listed as having access to Gmail.
Check your browser plugins - a number of services work via a plugin in your browser, so have a look at what is listed there. Ctrl+Shift+A in Firefox, or via Wrench → Tools → Extensions in Chrome.


Did Gus Fring really intended to replace Walter White with Gale when he asked Gale if he could cook Walter's formula Or was this Walter's fear?

Question: Gus Fring initially hired Walter for 3 months for his service, which he later extended it to 1 year. Of course, he wanted Gale to learn Walter's formula and replicate it eventually since Walter was more like a consultant and he had cancer.
But the way I see it was Gus wanted to have a back up chemist, since the cartels wanted Gus' chemist to cook for them, and this demand coincided with Walter killing his two dealers. Walter then panicked when Gale started to ask too much details about his methods and had him killed and he then wanted Gus killed. I mean Gus did tell Walter that Jesse should have let him deal with the dealers regarding the murder of the boy, So maybe Gus was not without reason.
Gus may have wanted to have a back up chemist since the last time he took a cook there, he was shot in the head. So hence he wanted Gale to learn the Walter's method ASAP.
After Gale's death, Gus went to Jesse, since Jesse had been with Walter from the start and he was right to assume that Jesse would be able to replicate Walter's product. He took Jesse to the Cartels, and Cartel being a prick tried to keep Jesse and Gus had to kill them all to keep Jesse and for revenge.
Did Gus really wanted to kill Walter and have him replaced with Gale or was this all Walter's fear?
Comment: Looks related if not duplicate to [Was Gus planning to kill Walt from the start?](https://movies.stackexchange.com/questions/21205/was-gus-planning-to-kill-walt-from-the-start)
Comment: I'd say a bit of both. If you remember the "fly in the lab" scene, Walter is becoming unstable and paranoid around that time. Gus is a very careful man and can't put all his money in one bag that is Walter. He needed a back up (sane) plan. Walt feared he was gonna be replaced yes but most importantly he feared someone else than him would be able to make his famous blue meth. Heisenberg can be the only genius meth cooker capable of this feat, right ? SO part fear, part paranoia, part jealousy
Answer: We know that Gus did intend to replace Walter at some stage, as he knew Walter was going to die.  Gus already had a dislike of Jessie and, if it wasn't for Walter, Gus would have killed Jessie; though he also knew Walter wouldn't work for him if he did it whilst he was alive.
It's likely that Jessie wouldn't have worked for Gus once Walt had died, or Gus would have killed Jessie soon after, so having Walt train Gale was a way of having the product live long after the creator had gone, and would ensure Gus was the number one producer and distributor for a long time to come.
I don't think Walt was scared of being killed particularly.  He was already living with the fact of his mortality day-to-day, it was more an ego thing for him.  He knew he was the best at what he was doing, and that Heisenberg had a reputation as a result of his work, so he wanted to keep that going to enjoy the power he had whilst he could.
Answer: In the scene where Gus comes to Gale's apartment and asks if he can take over / cook Walter's formula, and then pressures him to agree that just "one more cook" would suffice to master the remaining details, it's pretty clear he intends to kill Walt as soon as Gale can take over. He also makes a point to state that Walt is "dying of cancer" and makes it sound inevitable to Gale in that conversation.
Answer: Like all the best things in Breaking Bad, it's open to interpretation, IMHO. It's obvious the cartel wanted the recipe, not even necessarily a cook. We see that in season 2, when Tuco becomes paranoid and kidnaps Walt and Jesse with the intention to have the cousins drive them down to Mexico. Then, again, at the end of season 4, when Gus flies Jesse down, telling him that his life is now in the hands of the cartel (a dubious play).
The way I see it, there are a few scenarios as to what could've happened. I think, either way, Gus wanted Walt out. I do not think Gus ever intended to kill Walt, but of course, that's why it's open to interpretation. As Gus says to Gale earlier (when he's setting up the lab, it's later in season 4, but timeline-wise, it takes place during season 3), "I do not consider him a professional," when he informs Gale that Walt wishes to cook for him, but Gus won't hire him. This is the scene with the debate about 95% purity vs 99%.
But then we have the last episode of season 3, when Victor picks up Walt saying "there is something wrong with your lab." Mike is there and tells Walt "the sooner we get down there and figure out what this is, the sooner we can all go home, Walter."
But that begs the question, right? What was to "figure out down there?" There are many possibilities, but after re-watching the series nearly 10 times, I'm convinced that Gus never intended to kill Walt...at least not at this particular juncture. Which is what makes him such a complicated character, as he slits Victor's throat with ease in front of Mike, Walt, and Jesse. If Gus wanted him dead, he could've done it then: Victor knew the cook, Gale had it written down (though it was confiscated), and Gus recorded everything in the lab, thus recording the cooking processes.
In fact, Gus had multiple opportunities to kill Walt: when he comes over to make stew and Gus pulls a knife, then hands it to Walt. And especially when Gus fired Walt in the desert. Before, in the desert, too--after Walt killed Gus's gangbangers who shot Tomas. Mike even says on the phone in that scene, "Walter, I can kill you from way over here if that makes you feel better." Gus never informs Walt about the cousins coming to assassinate him (though Walt figures it out later). Gus leverages Hank's life in place of Walt's. If Gale or Jesse were to be Walt's successors, why would he barter Hank instead of Walt?
I believe Gus is arguably the most reasonable, rational, and even compassionate character in the show. Knowing Gus's backstory--and his quest for vengeance against the cartel--isn't just for power or control. It's to atone his hermano's death when he was shot in the pool. I also think Gus speaks truthfully when he asks Walt "are you asking me if I ordered the murder of a child?"
However, something was to happen in that lab.
These are all the possibilities I can think of:

Mike was sent to fire Walter. Hell, Gus may have even been in the lab, himself.  The "chemical leak" could have been an excuse to let Walt go, have him remove personal items, clean out the fingerprints, etc. As mentioned earlier, Gus fires Walt anyway at the end of season 4 (ep. 13). Jesse is the new cook, Walt is out. If Gus wanted to kill Walt, he would've done it then, too. But never did.
Gus was planning to take Walt to Mexico, in place of Jesse. We know the cartel wants the recipe, both from Tuco's perspective--as well as Gus's later, when he's sniped at with Jesse, at the single-wide trailers. Gus needed a way to get rid of Walt and Mexico was a viable option, considering Walt's increasing paranoia and lack of professionalism (to Gus). It's an easy way to get him out and have him out forever. Whatever his fate was, it was up the the cartel. Gus, at one point when he invites Walt over to dinner, confesses he's a family man--that he does this "to provide" as well.
Mike/Gus/Victor/All wanted to find Pinkman to replace Walt. Mike and Gus knew Walt killed the two gangbangers even before he confessed. Mike knew his car was jacked up; all they cared about was finding Jesse. It's not unreasonable to assume Mike would "beat it out of Walt," just as he threatens to do so with Saul, under Gus's orders. Very likely, they could've tortured Walt until he gave it up. In fact, when Walt gives up Jesse to save his own life, Mike stops with the inquisition and gives Walt his phone. Walt betrays him and sends Jesse to kill Gale.
Mike/Gus/Victor wanted to use Walt to find Pinkman. Both to succeed Walt and to help with the Mexico plan, as Gus learns over time that Jesse is more loyal and dependable than Walt. Mike got the "address" from Saul but never went down the wild goose chase. Mike is smarter than Walt, Pinkman, and Goodman combined and probably figured out it was a rouse in under and hour. Then he deduced that Pinkman was still in town and the only way to get to him was Walt. Gus wanted to set things straight, as he did with Walter in the desert when he says "you should have come to me and let me handle it," referring to the death of Tomas.
Kill Walt. However, this seems extremely unlikely, as Walt was the only connection to Jesse. Perhaps Mike could've tracked him down over time ("it's what I do, after all"), but time was significantly of the essence. Gus couldn't afford to draw more heat and attention. Also, consider the fact that Gus never tries to kill Walt--even after he temporarily turns Jesse. Yes, Jesse says he won't cook if something "final" happens to Mr. White. But think of how clever Gus and Mike are. Shit, they killed the other twin in the hospital, making it look like he succumbed to his injuries from Hank! Gus and Mike could've made it seem like Walt finally died of cancer. But never did. Even as Gus grows suspicious of threats against his own life, his only concern is killing Don Eladio et al and proving it to Hector. His quest for vengeance ironically sealing his own fate at the hands of Walt.
Answer: To me, the matter is simple.
Gus found out about Walt's cancer at the end of season 2. Roughly 8 weeks after that -- time period in which Gus hired Gale and set up the lab --, in episode 301, Gus made the "three-months offer" to Walt.
Thus, from the beginning, it was clear that all Gus wanted was for Gale to learn Walt's formula. Obviously, Gus figured: He'll die soon anyway, so he wouldn't be able to cook for very much longer, and at least this way he'll spend his remaining time with his family -- and 3 million in his pocket.
Now, Walt completely fucked Gus' plan over, when he forced Gale to leave (a major plot hole, in my opinion -- how could Walt be so dumb?). Now, Gus was stuck with Walt. This led to a lot of very bad consequences throughout season 3 and until the finale.
Comment: He forced Gale to leave so he could employ Jesse and thereby rescue him from a life of dissipation.  Not a wise choice, perhaps, but not absurd.
Comment: I understand, but like, even knowing he was directly confronting Gus by doing that? Seeing how he admired and feared Gus at that point, it seems like a death wish to me (or a plot hole).