Should web designers make a free mockup?

Question: I have some potential clients that ask to see something before accept the work.
Now, should I make, for example, a free mockup or It's better to find another client?
Comment: Should a plumber install a new toilet before you decide to hire them? Should a lawyer try your case before you decide to pay them? Should a ________ do work for you for free before you decide to pay them?
Comment: In cartoon form: http://freelanceswitch.com/freelance-freedom/freelance-freedom-158/
Comment: You can always make a video demo if you're worried about them stealing it.
Answer: That sounds like Spec-Work.
http://www.no-spec.com/faq/
You should show them what you are capable of (i.e. your portfolio) but be wary about doing any work for them for free.
Comment: Right on. I read over AIGA's policy a few months back. Their analogy really resonated with me..."You wouldn't expect an attorney to write a brief for you, and then decide if you'd pay for it. Let alone, go to 5 attorneys, and pick the best of them". (from memory...) http://www.aiga.org/content.cfm/position-spec-work
Answer: You should have a portfolio - pieces that show examples of the type of work you are able to do, the styles you work in, etc. If they're asking for a "free sample" of the page make sure you have a legal document in place to protect your work (and copyright your work before you sent them the "free sample").
There are plenty of legit people that can't imagine a concept well enough and need some kind of visual hint, but there are also plenty of evil little scheming people who want something for nothing (or who don't feel like design is real "work"). CYA.
Comment: I don't think you should ever consider giving them free samples of things other than work you've already completed (aka, a portfolio)
Comment: The legal doc may not be worth the paper it's written on...especially, if they take your design, and tweak it (just a little), then point to 4 other sites the "resemble" it. You also need to be prepared to sue someone that infringes your copyright. If you're not, don't use it as a bluff.
Answer: Stand your ground. Don't do SPEC work.
The client is interested in you (based on your portfolio, or word-of-mouth) - capitalize on that.
Offer "X" comps for the job AFTER the contract has been signed. That way you're both protected. They get their comps, you get the work (and paid). And no one will feel cheated, or slighted in the exchange.
Answer: The only time that comparing actual products makes sense is when you are buying something that is essentially pre-fabricated, like a subway sandwich where they ask a few questions about what you want and drop a few swappable pieces into a pre-prepared formula.
If this is your business model - if you bash out a lot of very similar designs quickly for people happy with something that isn't a great fit but does just about work - then spec work and mockups make sense. But this is the only time that they make sense.
If people want serious design work that really fits their need they need to understand how the design process works. Here's a classic diagram by Damien Newman:

If you're doing spec work, you would be going all the way through the squiggle and half way through the straight line before you even know you're doing the work: rushing through all the hard stuff and leaving only the final polishing. That's not just bad for you: you'll be cutting out so much of the important squiggle at the start that it's more or less impossible that you produce something that matches the client's need more than superficially.
Realistically, you're going to be recycling more or less the same concept as last time, with a few tweaks that are the equivelent of swapping tomato and mayo for peppers and chilli on a meatball sandwich.
The work will be average, but plenty of designers do make a reasonable living like this. There are plenty of worse ways to make a living.
For something genuinely good, however, that genuinely meets the need, it's never going to work. The majority of the work, time and skill comes in before the concept line: really understanding the context, and developing, testing and improving ideas based on a deep understanding of the client's actual need.
There are plenty of clients who are happy with average but professional-looking work that sort of fits their need even though really it was designed for someone else. There are plenty of middle-of-the-road designers who are happy to churn this stuff out. If that's not you, and if you think that's not really what they want, you have to make them understand how it works.
If someone asks you for a free knockup, you have to make them understand that they are asking you to essentially cut out or minimise the part of the process that has the biggest impact on the quality, effectiveness and relevance of the final result.
Comment: ...and of course, after understanding this, if they still just casually *expect* you to go through the whole process to the best of your ability for them for free, you really, really, really don't want to work with that person. It's not going to end well.
Answer: Most of my clients don't ask for a mockup and to my surprise a long time client this time asked for one because he's asking cost estimates to other suppliers and also the respective mockups...
I don't really like the idea, because there is a chance of not getting the job, but even so, my advice is to make a mockup good enough for the preview but not good enough for the final piece, in other words, something that points them into where you're leaning in terms of design.
Also lawndartcatcher's suggestion of a legal document is very good!
In other cases, unless it is worth it or you really need it, I don't "accept" making free mockups and the clients most of the time understand that.
Answer: It is actually your choice. I remember when i first starts make carrier i used to make lots of free mockups. But as you go further in the road, you make some reputation then you won't have to.
But when you provide mockup it is always possible that people will run away with your work! I have seen lots of these kinds of projects in freelancing sites where clients wants to make psd from jpgs. :( That's why my recommendation is strong portfolio. Doing a demo video is also a good idea.
Answer: If you need the client and are low on work, I don't see a problem with doing a mock-up to sell the client on giving you the job.
On the other hand, if you have plenty of work, it would seem unwise to do something like that. In addition to this the client who is asking for a free mock-up might be quite a bit of trouble and waisted time down the road. I have dealt with clients like this who have turned out to be very indecisive and cheap.


Are yawns contagious?

Question: I guess that this might be a little bit of an extension of the question "Is yawning contagious across species" that was earlier asked. But my question is, is yawning contagious at all? Is there any evidence that supports the idea that a person is statistically significantly more likely to yawn if in the vicinity of another person that is yawning?
Comment: Reading this question and answers made me yawn
Comment: Possible dupe or at least related: [Is yawning contagious across species?](http://skeptics.stackexchange.com/questions/1326/is-yawning-contagious-across-species)
Answer: Researchers tackle the mystery of yawning

Only about half of adult humans are
  prone to contagious yawning. In his
  tests, Dr. Gordon Gallup found that
  susceptibility to contagious yawning
  is linked to people's success on a
  face recognition task. Those who are
  more susceptible score lower on a
  measure of schizotypal disorder, a
  personality disorder characterized by
  a need for social isolation.
Gallup's later studies used functional
  MRI, or fMRI, to view subjects' brains
  as they watch another person yawning.
  He found that this experience triggers
  "unique neural activity" in areas
  which play a role in self-processing,
  such as autobiographical memory. "Our
  findings provide further support for
  the hypothesis that contagious yawning
  may be part of a neural network
  involved in empathy."

Dr. Catriona Morrison and a team of researchers from the University of Leeds in the United Kingdom came to a similar conclusion:

Those who succumbed most to contagious
  yawning were the individuals who
  scored higher on the empathy test.
  Psychology students scored
  significantly higher on empathy and
  yawned more often than engineering
  students.
"We worked with psychologists because
  they are widely regarded to be more
  empathetic and engineers because they
  are often seen as 'systemizers', who
  are more interested in objects and
  functions than people," said Dr
  Morrison. "We found the psychologists
  yawned contagiously more than the
  engineers."
Comment: Now that I think about it, I do dislike people. This explains why I picked engineering over psychology. I think this is an objective but functional view of yawning.
Comment: Now that I think about it... seeing people yawn makes me feel weird...
Answer: I would say one is more likely to yawn if looking at someone yawning, but statisticaly it is tricky to answer. You can measure how many times a person would yawn seeing somene yawn as well, but you can't know if that same person would not yawn at the same time if the situation was different and no one was yawning infront of their face, because yes and no can't exist at the same time.
There are studys about yawning to read, like one made with children, or  an experiment report. In the second one they showed videos of people being neutral, laughing or yawning to people.

The incidence rate of evoked yawning in response to watching yawning videos was 41,5%, while the rate of evoked yawning in response to non-yawning videos was only 9%. Of those who showed contagious yawning 60% yawned more than once.

But the fact that studies are being made about this would logically lead to the conclusion that there is an exsisting phenomenon detected, therefore, yes, yawning is ''contagious''.
Answer: For a more ad-hoc 'study' the MythBusters TV show (in this episode) had an experiment their conclusion was that yawns are contagious. Their largest experiment involved a samples size of 50 people.
From the wikipedia summary:

In a second test pool of 50 people where only the influence of Kari's yawn was used, those who were influenced into yawning by her yawned 29% of the time. However, those who were not influenced yawned only 25% of the time. It seems that the MythBusters also found the average time to yawn for those who did yawn was 9 minutes for those who had been influenced and 9.6 minutes for those who had not. This was enough for the MythBusters to give the Confirmed rating, although there was the 4% difference between the experimental and control groups...

Are yawns contagious?


Can you say "leftside right"?

Question: Can you say something like "I turned the box leftside right" in English? Or what should be used in place of "leftside right"?
By "leftside right" I mean pivoting by 180 degrees.
Comment: Comments are not for extended discussion; this conversation has been [moved to chat](https://chat.stackexchange.com/rooms/90469/discussion-on-question-by-happy-can-you-say-leftside-right).
Comment: How about, flipped sideways?
Answer: I wish you could - it's just a logical transform of "upside down" and I would understand it. Sadly, many people struggle with left and right, and that coupled with the fact that although some 3D shapes such as boxes definitely have a right and left side, others are more ambiguous (clothing, for example).
It's more common to use "back to front", as in:

"The box was back to front so I fixed it."

or

"I put my trousers on back to front"

There's still the implication of a 180 degrees rotation about the same axis that you describe, but there's no longer the need to figure out left and right.
Comment: Comments are not for extended discussion; this conversation has been [moved to chat](https://chat.stackexchange.com/rooms/90470/discussion-on-answer-by-pam-can-you-say-leftside-right).
Answer: No. I'm a native British English speaker and wouldn't have a clue what you meant by "leftside right".
I would suggest describing the action in terms of positioning the faces (left, back, right, front, top, bottom), e.g. "Rotate the box so the left side is facing the front".
Comment: @Happy Even better reason to not use leftside right, here's a native speaker you confused.
Comment: That's 90 degrees, when the left side faces the front.
Answer: I think "back to front" is what you are looking for, but in my experience as a Canadian, it is not a very common term in American English.
The synonymous term in American English is "backwards".  That said, the connotation might be a bit different.
For example, using it the way you used "left-to-right" it may not be a perfect fit.  "I turned the box backwards" has some implication that the original position was where it was supposed to be, but I believe most would understand it.
Comment: I'd say "The box was backwards, so I turned it around."
Comment: "I turned the box around"
Comment: @Phlarx I was actually thinking of including that example in my question; but then it seemed to branch away from what OP was getting at.
Comment: Of course, but I think it is worthwhile to describe the expected structure of the phrase so that OP can decide for themselves if they want to deviate from that form.
Answer: "180 to the left" is the most natural way I can think of to express it.
In skating/snowboarding, it would be a "backside 180", assuming regular stance ;)
Comment: Comments are not for extended discussion; this conversation has been [moved to chat](https://chat.stackexchange.com/rooms/90471/discussion-on-answer-by-illarion-can-you-say-leftside-right).
Answer: You can say whatever you want in English.
But unless you're trying to be funny/clever/etc., yes, I would refrain from saying "leftside right", or "rightside left" for that matter.
"Leftside right" is likely unclear to many native speakers just because it's a word and phrase that isn't used.
Inside-out, Upside-down, and other such phrases are in the vernacular, as are the words "inside" and "upside" (as well as "outside" and "downside").
"Leftside" and "Rightside", however, are... less common.
Alternatives
Around is a fair substitute:  "I turned the box around."
See also:
"She turned around and looked."
"He really turned his life around."
"If you kids don't stop, I'm going to turn this car around!"
Answer: The most common way of telling someone to turn something so that it is facing the other direction is:

turn around.

This is the usual way to say 'turn something 180 degrees from side to side'.
If it is facing to the left, then afterwards it should be facing to the right.
If it is facing you, then it should be showing their back to you afterwards. This is often misinterpreted as turning a complete circle so as to face the same way again afterwards, but that is hardly ever what is intended.
You can say 'leftside right' and that would be understood, but it is not a thing any body actually says ever, at least not for telling someone to turn something. Urban Dictionary has a description meaning reverse like in a mirror, but I can't find any other web instances of it actually in the wild.
Answer: In most cases where one rotates an object 180 degrees about a horizontal axis, it won't matter which horizontal axis one is using.  What will matter is that the parts of the object that were oriented up are now oriented down, and vice versa.  It wouldn't generally matter whether the parts that had been in front stay in front, or the parts that had been on the left stay on the left, or neither, so there's no brief term that makes such distinctions.
Rotating a box 180 degrees around a vertical axis will flip it left-to-right and front-to-back.  Such a move is generally called "turning it around" or perhaps "flipping it around".
For operations which flip an object around a single axis only (typically only applicable to operations on a computer, images, or other "virtual" objects), one would typically say the object was flipped top-to-bottom (not upside-down!), left-to-right, or front-to-back.  Note that "flipping an object upside-down" typically involves flipping it about planes that are perpendicular to a vertical axis and another unspecified axis, and "flipping the object around" would involve flipping it about planes perpendicular to both front-to-back and left-to-right axes, while flipping top-to-bottom, left-to-right, or front-to-back would only involve reflection about a single plane.
Answer: tl;dr: be clear.
As Hot Licks points out, you could -- the trouble is, people wouldn't understand you.
If you need your listener to know how you turned the thing (or which way up it is now), you will need to make that clear -- and your suggested "leftside right" fails to make it clear. Even if your listener understood that the side that used to be on the left is now on the right and vice versa, you haven't said whether you turned it around a vertical axis or about a front-back axis. What is the best thing to say? I think it depends to some extent on what is plausible in your context (is the object so heavy that it can't be turned about a horizontal axis even though it can be slid and turned around a vertical axis?).
Anyway if the context doesn't resolve the ambiguity, I'd favour being explicit even if that means a lot of words, e.g. "I turned it upside-down so that its left side is now on the right" or "I turned it around so that its left side is now on the right". Just "I turned it around" (as Mitch suggested) sounds nice but I still have a nagging suspicion that in some contexts people might not be sure which way you turned it.
Answer: Other answers like "flip the box around" sound natural, but if you're looking to maintain the focus on where the left side ended up, I would go with "I turned the left side of the box towards the right."
Answer: As a native English speaker (I'm English), I'd just say "turn it 180" - the direction doesn't matter unless it's important.

Can you say "leftside right"?


Why are integrated circuits powered by low voltage and high current?

Question: I've heard that a typical graphics card uses around 100 A of current and only 1 V of voltage. Is there a specific reason why not to use the other way around, so high voltage and low amp? Usually high current leads to high losses, that's why power transmission lines usually prefer high voltage instead of high current. So what am I fundamentally not understanding why that is a bad idea for integrated circuits?
Comment: @mkeith Not particularly. I just picked a graphics card as an example because I thought that all ICs followed the same logic. Turns out that I'm wrong. So your suggestions would be a kind of follow up question, but not what I initially wanted to know. Thank you for the sugestion.
Comment: IC's dont split a high voltage into smaller voltages with more current - that's an AC thing for power lines. (yes, i know, buck/boost converters exist, im talking purely about AC power lines here). each transistor needs a small voltage but the many transistors need that current. See my answer (now edited) for a more indepth explanation
Comment: Most IC's are low voltage and low current. It is true that some power hungry high speed digital IC's use very high current. I guess your question is, could those high current IC's be designed differently so that they use high voltage and low current?
Comment: @Maxim Modern digital ICs use CMOS gates. CMOS gates are a bit special - they don't behave like traditional resistors (your description of current loss). CMOS gates use zero (almost zero as to be effectively zero) current when idle. They only consume current when they switch state (from on to off or off to on). As such, the current used by graphics cards is a function of MHz/GHz and if you increase the voltage you WILL use roughly the same current thus increase Watts - to decrease Watts you reduce the voltage from 5V to 3.3V to around 1V
Comment: @Sean I'd far rather touch a 5V connection that supplies 10kA, than a 10kV 5A one. The volts determines the actual current that will flow through the body (and at 5V, that's almost none). You can have a power-line at 200kV with zero current flowing, but it's still lethal.
Comment: Also, high current means high heat generation, and is more dangerous if you stick your finger into it, than high voltage.  (The reason high-voltage power lines are so deadly is because they _also_ carry very high _currents_.)
Comment: re: "I've heard that a typical graphics card uses around 100 A of current and only 1 V of voltage." Actually it's the chip that uses 100A, not the card. The card uses 12V, for the reasons you've noted. There is a step-down converter on the card.
Answer: I am not sure why this wasn't the first thing pointed out by any of the earlier answers, but it is because as transistors are made smaller to increase speed, increase density, and reduce power consumption, the gate oxide layer is made thinner (which also increases leakage currents).
A thin gate oxide layer can't withstand very high voltages so you end up with a device that only operates at very low voltages. Thin oxide layers also have more leakage so you don't want a high voltage anyways since that would just increase leakage current and increases static power consumption.
Your mistake is this:
Data processing, unlike power systems, isn't about power delivery; It's about data processing. So it is not that designers choose to operate at low voltages and high currents thus going against \$I^2R\$. Yes, they are concerned about power consumption and heat due to losses, but they aren't concerned with the efficient delivery of power. A power designer has to deliver X amount of power and would increase voltage so they could decrease current while delivering that same power. A digital designer would outright decrease the "power output" if they could.
Their optimizations necessitate low operating voltages which results in high leakage currents. The goal of these optimizations is to allow smaller transistors so you can pack more of them in as well as switch them faster, and when you have millions upon millions of transistors switching very frequently that results a lot of charging/discharging the gate capacitances. This dynamic current results in the high peak currents which can be  tens of amps in high-speed, high density digital logic. You can see that all this current and power is undesired and unintentional.
Ideally, we would like really no current at all because our concern is information, not energy/power. High voltages would also be nice for noise immunity but this runs directly counter to making transistors smaller.
Comment: Further reading: [Modern Microprocessors
A 90-Minute Guide!](http://www.lighterra.com/papers/modernmicroprocessors/) has some discussion of the fact that higher frequency typically requires more voltage to push charge around faster.  But at higher voltage, that's more charge for the same gate capacitance, so power scales with V^2 at constant frequency.  And increasing frequency means pushing the same charge around more often.  So assuming you run at minimal V for any f, power scales with f^3 as you increase frequency and voltage to make it work.  The "power wall" is the limit of power density
Comment: (The part that scales with f is the *dynamic* power from charging and discharging the tiny capacitance.  When most transistors are flipping, dynamic power tends to dominate, but leakage current is significant for stuff like large caches, or execution units that are often idle.  https://en.wikipedia.org/wiki/Dark_silicon - power gating is important for modern CPUs)
Comment: Your point about information processing is a good one.  Especially since heat is thermodynamically created in a processor when memory is erased.  If it takes more energy to activate a cluster or transistors that comprise a bit of memory, that much more energy is pushed back out as heat.
Answer: The power required to switch a capacitance from logic 0 to logic 1 (or vice versa) is proportional to the clock frequency times the supply voltage squared. In CMOS digital circuits the logic gate inputs look like capacitors, so charging and discharging capacitances uses most of the power in these circuits.
As you mention, the \$I^2R\$ losses in conductors will go up, so the low voltage power supplies are placed as close as possible to the processor. Look at a modern motherboard and you will see a 12V connector very close to the CPU. You will also see several large inductors and capacitors...these are for the low voltage switching power supplies.
Answer: In addition to Elliot's point about the power required to charge the tiny capacitances associated with each transistor in a GPU or high performance CPU. consider the size of each transistor.
In the early 1980s people didn't worry much about electrostatic protection, but I started paying attention when I first came across a transistor with a 1 micron gate insulation width (in 1982). It's electric field strength (volts/metre), not just voltage, that causes high voltage breakdown.
You can get a lot of V/m across a micron.
Now, minimum feature sizes are a couple of orders of magnitude smaller, so connecting the tiny transistors in a CPU's core logic to the traditional 5V supply would simply destroy them.
I/O transistors were built outsize and especially tough, and chips used separate supply rails for the I/O interconnections. But increasingly, even these can only tolerate 3.3V, or even down to 1.8V. In FPGAs, pretty much only trailing edge devices are still 5V tolerant.
Answer: My answer is similar to DKNguyen's excellent one, but I'll phrase it differently.
First, in an integrated circuit, voltage and current are independent. Ideally, you want both to be as low as possible. But as always in engineering, there are design conflicts that force you to make tradeoffs.
So let's look at voltage and current separately.
Voltage
There are some points to be made for using a high(er) voltage, and some for a lower voltage. The original TTL logic (such as most of the chips used in the 1977 Apple ][ computer outside the CPU itself) ran at 5 volts. TTL logic is still ubiquitous; you can still buy most of the same chips Steve Wozniak used in the 1970s. In landline phone systems, the dial pulses (which really are just digital bits if you think about it) used as much as 48V.
Today, you go down as low as 1 Volt.
Pros for high voltage
Reliability. If you have a poor-quality circuit (such as a 7-mile thin copper telephone wire), it's much easier to reliably tell the difference between 48V and 0, but darn near impossible to tell apart 1V from 0V. Basically high voltage "just works" no matter what.
That's pretty much it. In today's highly integrated circuits, which are really extreme precision instruments, and with 50+ years of manufacturing experience to achieve this precision, you don't need that kind of ruggedness, so lower voltages work just as well.
Edit: as Peter Cordes pointed out, higher voltage does have a second advantage; it can allow increased speed because the voltage reaches the threshold of reliable detection quicker. I hope I paraphrased that correctly.
Pros for a low voltage

Low energy consumption, which translates to longer battery life and less heat output. Edit: Peter Cordes pointed out that lower power consumption also translates to the chip simply not melting. That's a very real problem. Some CPUs will actually explode in a matter of a few seconds if you forget to put on a heat sink.
Higher speed. There simply are fewer electrons to shuffle around (although that technically depends on the charge rather than the voltage, these two are linked in practical terms).
You can use thinner insulators without having to worry about current breaking through. That translates to thinner insulators. Exception: floating-gate transistors are actually designed for current breaking through an insulator. That's why writing and erasing flash memory takes a high voltage.

So when you are talking about a computer circuit, low voltage clearly wins.
Current
Now let's look at current. As DKNguyen already pointed out, designers also want to keep the current as low as possible, in part to reduce heat, and in part to extend battery life in smartphones etc.
But to understand what's going on, you really shouldn't be looking at the 100A, or whatever it is. That might be an average, or more likely is an average when there is heavy graphics load.
If your graphics card was perfectly inactive (which it never is, not even close!), the current would actually be close to 0A. The transistors in microchips are (somewhat simplistically speaking) usually arranged as CMOS transistor pairs in series, where always one is in "on" mode and the other in "off" mode. So current can never flow, in theory. In practice, when the transistors switch, for a very short time, there usually is a very short period (measured in picoseconds) when both are "on" - basically, a short circuit. This switching happens billions of times per second (depending on the GPU's clock frequency, mostly), and in anything from a few thousand to millions of transistors at the same time, depending on how active your GPU is. So your 100A is actually not constant 100A, but a series of nearly 0A, followed by extremely short spikes of potentially even a lot more than 100A.
Edit: Peter Cordes also pointed out that the 0A is an idealization in the first place. There is a lot of parasitic current leaking through the transistors, as well as pretty much everywhere on the chip.
There is a second issue with current. A lot of components (such as the bits in dynamic RAM) in a chip act as capacitors (they are actually transistors wired as capacitors). Writing 0s or 1s into such capacitors means storing or removing electrons from the capacitors. The higher the current (and the smaller the charge), the less time that takes. Edit: as Peter Cordes pointed out, besides the capacitors in the circuit intentionally, there also is a lot of additional capacitance all over the place (for instance from components or wiring being just adjacent), which also contributes to the same problem.
To reduce current, designers have a few options:

Reduce speed. That reduces the number of switching operations (and therefore current spikes), and also allows charging or discharging the capacitors at a lower rate.
Turn off parts of the circuitry that isn't used right now. Again, that is done during sleep mode.
Reduce the time when both transistors in a pair are "on" so the spikes are shorter.
Lower the voltage. According to Ohm's law, lower voltages translate to lower currents.

The first two are mostly done in sleep mode, and also when a computer starts to overheat. Infamously, Apple also at one point slowed down their iPhones to reduce current consumption when the batteries started to get old.
Losses
You also mentioned high losses in power lines (where voltages are high and currents are low). That's a very different situation. In a computer, the losses are always 100%; nearly all electricity is converted to heat (except for a few that are converted to light, radio energy for WiFi or the like).
So the goal isn't to reduce losses, but to reduce the total power.
Comment: For a given gate capacitance, higher voltage overall lets you run faster (at the cost of more power: power scales with V^2 from pushing more charge around, and having more energy per charge).  That's why over-clockers raise the voltage on CPUs, and why regular DVFS idle vs. turbo raises voltage along with frequency (https://en.wikipedia.org/wiki/Dynamic_voltage_scaling). If you're running at just barely enough voltage for logic to even work, it takes longer for next gate's input to stabilize at a "definitely on" state, increasing gate delay. This applies when we're talking 1.2 vs. 1.1V, not 48
Comment: So the benefit to low voltage is that it makes high speed possible *without melting*.  As http://www.lighterra.com/papers/modernmicroprocessors/ explains, power density became the obstacle in around the pentium-4 era, putting a ceiling on CPU frequency gains and ruining Intel's plans for a very high frequency but deeply pipelined CPU.
Comment: *close to 0A* - only with power gating of idle parts.  Tiny transistors have significant leakage current in the "off" state.  The smaller the feature size, the worse the problem, so static power becomes more of an issue compared to dynamic power.  (Dynamic power will usually dominate, though.)   Also, there's a typo in there: you wrote `0V` once.  But overall good answer, going into details about relevant factors.
Comment: *A lot of components (such as the bits in dynamic RAM) in a chip act as capacitors* - My understanding is that parasitic and gate capacitance is actually where most of the (dynamic) current consumption in CMOS logic goes.  Not just DRAM which is designed to have some capacitance.  Perhaps that's what you meant by "a lot of components", but maybe it would be better to be clear that most of the capacitance is parasitic, *not* designed in on purpose.
Answer: The many transistors in an IC are connected to the VCC and ground lines, not to each other - so they won't be "sharing" voltages so to speak like they would in series (which doesnt make sense for CMOS as it relies on restoring logic of current passing from a strong VCC source, not daisy chained through some million transistors).
CMOS blocks are all connected to the same VCC so they'll take more current with the same voltage - as if they were in parallel. Because the transistors need only 1V to work, you only need 1V. But, there are billions of transistors - and you need to source current to every single one of them. Thats why you have a hefty power supply and decoupling capacitors to source the 100A or so current in times of need (long story short the power lines can act as an inductor and when the billion transistors switch on at the same time, they need a HUGE rush of current - decoupling capacitors provide this when the wire is still opposing the huge current rush).
Thats why you need a lot of current but a small voltage.
EDIT:
To add about the power transmission lines, it is true that the lower current results in lower loss but these are AC lines and you can use a transformer to convert it to a lower voltage with a higher current (i.e. when the power lines get to a town and the houses need 230V and not a few kilovolts). That is a fairly different concept here, as IC's use DC only. I believe your underlying question was regarding the use of high current in ICs and not necessarily the IC's capability of converting between high/low voltage and current. I can definitely understand your confusion between the topics however - I hope my answer explained it.
Answer: I will give you my answer which is based on digital logic 101 which I took many years ago. Power loss in a clocked integrated circuit is given by this formula:
P = V^2 * C * F
Where P is power, C is the capacitance, V is the voltage (VCC) and F is the clock frequency.
This is why power hungry chips are optimized to minimize VCC. If they used a higher V they would consume even more power.
Note that C is the process capacitance for the transistor level geometry and type of fabrication used.
In particular the MOSFET gate layer may be made extremely thin in low voltage IC's. However, this also increases capacitance, C. So there are trade-offs. But since the power is proportional to V^2 it is usually worthwhile to minimize V.
Comment: Technically this is only one component of the power. This is called the dynamic power or switching power. There is also leakage power because the gate insulation layer is not perfect, and some current flows through it even when the clock is stopped.
Answer:
Higher voltage breaks transistors.

Modern transistors are tiny, and cannot withstand high voltage. The smaller we make them, the lower the voltage has to be, to prevent electrons from jumping between traces and destroying the device. Historically it was 5V, then went down to ~1V in current equipment. Think wire insulation - wires rated for 10k volt have vastly thicker coat than wires you find in toys.

Transistors use a lot of current (amps) because there is a lot of them. Expect 10 bilion in modern device (1 000 000 000).

Other answers dig into details as to why is that.

Power efficiency

As you noted yourself, it would be beneficial to send 1A at 100V than to send 100A at 1V.
In fact, manufacturers already do this!
CPU and video cards often have a dedicated 12V connectors, and only convert to ~1V right before it goes into processor. You can see array of capacitors and converters around the processor (rounds and box pieces, often with own heatsink). You would be surprised how much current flows there (100 of ampere) and how many processor 'legs' are dedicated solely for powering it.


How Would I Make an Oceanless World Feasible?

Question: The planet I'm thinking of is of similar size and distance from its star relative to Earth, but it lacks oceans, instead consisting of one massive continent with a huge mountain range (reminiscent of the Andes) running east-to-west around the equator, forming an almost perfect mountainous "ring" around it. To the south of this mountain range is a vast tropical rainforest, and to the north is a massive desert. The mountain range itself tends to chop up air masses and creates microclimates. How feasible would a world like this be, and what changes to the climate I already have set for it would I need to make to make it be able to support human civilization with no oceans?
Comment: If the are no oceans, then where does the rain come from to feed the rain forests.
Comment: Start by reading up on plate tectonics.  Your mountain range doesn't fit that theory well.
Comment: @AlexP Thousands or millions of small and large lakes can supply water to the water cycle just as well as deep, planet-spanning oceans, perhaps with a few degrees warmer climate.  The equatorial mountain range can't form from plate tectonics as we know them (plates may not drift at all without large amounts of water to lubricate the boundaries).
Comment: @ZeissIkon: What counts is not the depth, it is the free surface of the water reservoirs. If those millions of small lakes have enough surface to feed the water cycle, then I don't fully see how they won't form an ocean.
Comment: @AlexP Water gathering in impact craters that haven't yet eroded away?  I don't know, it's not my world, and there are multiple answers telling the questioner that it won't work that way if it's science-based.
Comment: @ZeissIkon three of Saturn's moons have equatorial ridges. There is some mystery surrounding the source of the ridges though. Some may have been rings like Saturn's which fell and accumulated on their surfaces. Iapetus' ridge is different and its origin is not clear.
Comment: An ice moon could get a ridge by erupting enough water from below the surface to shrink the moon -- and in the process contribute ice particles to Saturn's rings, making them much more visible and longer lasting than they should be...
Answer: You can't, unfortunately.
Without surface water you won't have a sustainable hydrologic cycle to keep life flourishing in the variety and density of a tropical jungle. Water will disappear into the crust beyond the reach of any root system (the Earth's crust is estimated to contain as much water as all the oceans, if not significantly more) in greater volume than it can be replaced through volcanic outgassing transpiration and evapouration. You may have noticed the Amazon, Congo, and other jungles are restricted to certain parts of the world: where prevailing tropical winds bring moist sea air inland, not just any coast at any latitude, and not just anywhere on land.

To the south of this mountain range is a vast tropical rainforest, and to the north is a massive desert.

An Earthlike world that isn't tidally locked cannot have hemisphere-wide climates, due to atmospheric circulation patterns and unequal heating. Handwaving the lack of water for a moment, you would still have bands of different climates where convection cells rise and fall. But without any surface water, you would have a planet-wide desert (cold at the poles and elevation, hot between, but desert).
Comment: @CJDennis Tropical rainforests are fed by the moist prevailing winds coming off oceans, on the windward side of elevations—note the Amazon is not west of the Andes; the ITCZ aligns with Africa's greenest bands—but more salient is the lack of *tropical* jungles outside the *tropics*.
Comment: ^evap**o**ration. I'm not sure your statement about prevailing sea winds explains all rainforests. See the maps on https://en.wikipedia.org/wiki/Rainforest
Comment: The Midwest in the US creates a lot of its own rain from the transpiration of the plants (once prairie, now a lot of corn and soybean fields).  Like a terrarium, the plants literally water themselves.
Answer: Here's the problem:  you have posited that there is free water, and plenty of it ('rainforest').   So,  where is that water going?  Either you have lots of lakes, or they get bigger and are "oceans."  In either case, over time these water bodies will get salty just as they did, and do,  on Earth.
Next: do you want this planet to be habitable when humans come to visit, or are you positing carbon-based life developing on this planet?  It doesn't really matter except for the possible difference in atmospheric composition:  sufficient oxygen, for example.
Comment: Wouldn't it be possible for the underground to be more porous than that of Earth, so the water would always 'drain' into the underground instead of lie on top where it can form oceans? Add a way for it to get back up (e.g. mega-geysers!) and you could still have a rainfall cycle.
Answer: On Earth, oceans exist because rainwater runoff collects into large pools called "oceans".  Oceans are at the lowest point on earth, so the water has no where else to go, and it stays there until it evaporates.
Ways to eliminate oceans:
Bury the oceans.
Earth's mantle contains at least as much water as all of Earth's oceans, dissolved in various minerals.  On your planet, in the northern hemisphere, the crust is very porous, and the ocean water sinks into the mantle at a high rate.  If the mantle is able to retain all of it, then most of the water will be lost off of the surface and be trapped deep underground.  In other words, the water table will start tens of thousands of meters under the surface.  This will result in a great northern desert.  Vapor water might re-enter the surface water-cycle from volcanoes.
Put the oceans in holes.
In this scenario, you will still have oceans, but they will take up very little surface area.  The planet has many very deep fissures (much deeper and much more frequent than the Marianas Trench).  The total volume of these fissures/trenches is such that the oceans can entirely fit inside of them.  If you look at a map of the planet, it will (misleadingly) look like the planet has almost no water, because the planet will be almost entirely land area.
Freeze the oceans.
If the planet's star is very weak, you could force the planet to be tidally locked to the star.  The near side would be temperate, and capable of supporting a water-cycle and rain-forests.  The far side  would be a frozen desert, like the Antarctic Desert.
Answer: Plants
In the book "The Stone God Awakens" by Philip José Farmer, humanity engineers trees to provide living quarters. Over a vast amount of time, humanity is gone and the trees have supersized and taken over almost all the planet.
If you have the seas becomes a glorified mangrove beneath the root of supersized plants, you could create the effect you're looking for. The seas are still there but buried under a mile of roots and leaf litter.
Comment: Just the covered ocean idea might work, it might not need to be engineered given the right conditions.
Answer: Terraforming
Seriously, lack of oceans makes it extremely unlikely that your humans and the trees in the rain forest evolved on this planet. It is simpler to assume they were imported from somewhere else by people capable of interstellar travel and artificially creating an environment capable of supporting them.
In this scenario the high dividing mountains would have been created artificially. Either by artificial volcanism or by dropping lots of space rubble on the equator. Either case this would have been used to add volatiles to the surface.
Moisture needed to maintain the rain forests would be provided by terraforming machines pumping up moisture from the mantle or other deep reservoirs. These were either only built or only work on one hemisphere with the other having dried out as water has been absorbed by the ground or lost to space. In the latter case the atmosphere in general would be artificially maintained at reasonable pressure with provided nitrogen and oxygen crossing the mountains but water coming down as rain due to the mountains
Answer: Rain cycle and water storage
I haven't seen any answers discuss the possibility of having a water cycle just from the evaporation of water in the plants in the rainforest. The rainforests on Earth evaporate huge amounts of water just from the plants' surface area. This evaporation can then fuel cloud formation, resulting in the necessary rain.
Combining this with a porous surface layer beneath the forest that can hold the bulk of the water, you might not need the 'open' surface water of oceans. A clay-like ground layer beneath the porous layer could then keep the groundwater from seeping deeper into the crust.
Equatorial mountain range
Coming from an astrophysical point of view, I think your equatorial mountain range is totally possible, even without the plate tectonics! In the formation of this planet, there might have been a ring of debris around it that has accreted onto it over time, leaving a perfect ring of mountains. Plate tectonics would probably even ruin this scenario, since the ring would be broken up and become dispersed or even disappear entirely.
Desert above, forest below
The formation scenario for this sharp ecological divide from south to west is a difficult one. If such a flourishing forest would arise in the south, why would the north be a wasteland? I can imagine a couple of scenarios.
1) During formation of the planet, two major (protoplanetary) bodies collided, and the material of them did not mix very much. This would give the possibility that the one side of the resulting planet has a surface with unfavorable conditions for complex life to evolve, while the other side has good conditions.
2) An asteroid impact in the north erased most life on that side (in a long lasting winter due to obscured skies) while the mountain range kept the impact of this impact (pun not intended) on the southern hemisphere small.
Comment: Welcome to worldbuilding . Please take the [tour] and when you have some free time read-up in the [help] about how we work. Great first post.
Comment: No answers discuss it because it won't work, the ambient humidity will be so low even desert plants will die in days. also rock will not just store the water it will actively remove it from the hydrological cycle through chemical reactions.
Comment: I am no expert in biology - why would the ambient humidity be too low? If every plant would basically have its roots in ground water, they could keep evaporating until the humidity would have gotten to a good level no? And about the rocks, that's true, but that's why the ground needs to be covered by some sort of soil and below that a clay layer for instance.
Answer:
Our solar system has far more planets without (water) oceans than ones with oceans. The hard part is making it habitable as well, and the request for rainforests.
So long as it doesn't need to be too hard-sciency, here's my go for an explanation.
There used to be more water, there used to be oceans. A few centuries ago, some event removed a significant amount of water from the environment. Maybe it was an asteroid impact, maybe enough soil-mass was lost and the water simply sank underground. For whatever reason, there is now less above-ground water than their used to be.
This means that the land has giant salt-flats where the oceans used to be. The rivers still run into the sea-beds, but the sun evaporates the surface water as it spreads out on the river delta's. Thus you can have rivers, maybe even lakes in the mountains, but on the old sea beds the water is just gone.
The old seas are needed to create large lifeless (salty) areas where the water can evaporate and provide the hydrological cycle. Over time, the salts will gradually wash downhill in the sea beds after floods and the sea beds will become habitable and the hydrological cycle will change. But for a few centuries, perhaps, you can have rainforests and no oceans.

Reality check: the loss of water from the atmosphere would probably cool the planet significantly which would probably result in surface ice rather than desert, but, eh.
In my mind this sort of environment can probably be handwaved - you may not need to provide a detailed geological account of how it occured. In Dune, Frank Herbert never explicitly stated why the planet Arrakis was a desert planet, it simply was and few readers questioned how possible it is.
Answer: You might be able to design a tidally locked planet around a red dwarf with properties like this although you'd have to have oceans on the back side underneath a deep layer of ice and at least somewhere on the side facing the sun with some open ocean. That could explain in part your rain shadow effect. If you have one large Pangea like continent set up kind of as follows: from South to North or reversed:
South<-- Ice here <-- small surface ocean<--Expansive Desert <-- Continent dividing Mountain Range <---Tropical Forests <--- More ocean <<
Ice here <- North <
Dark side hemisphere is ocean covered in ice.
The mountain range would "bisect" the continent and winds coming from the dark side across the northern ocean would bring moisture that would be dumped on the tropical rain forest areas. Problem: Polar Winds coming from dark side might be extremely dry. For rain you need a source of water that can go into the atmosphere. You might get some from sublimation of ice from the dark side and then water would flow back to the dark side in rivers to freeze sublimate and rain again. Look up papers for rain shadow effects and tidally locked worlds and you might find a suitable solution.
Ideally however if you have plant life evolving on your planet I would say you need a source for your water cycle and that means a large source of water that cycles from one form either solid to vapor or liquid to vapor to allow for rain shadow effect, rainfall and flow back to whatever the large source of water is.
Completely oceanless might be feasible but I think you'll need some large water body that is intermediate between your source of rain water and where it ends up in the cycle.
Another possibility might be some kind of groundwater but that seems a bit far-fetched to me.  Anyway hope this helps.


What is the story behind the "Linode problem"?

Question: What is the story behind the "Linode problem"? How did the service become compromised and what has exactly happened because of it?
Comment: Related: http://bitcoin.stackexchange.com/questions/3765/what-is-the-story-behind-bitcoinica
Answer: The "Linode problem" is storing Bitcoins on a managed device.  That managed device might be server hosting from Linode, for example, or a cloud server at RackSpace for another example.  In both instances, by simply gaining root access using the service provider's systems, tens of thousands of bitcoins were stolen.
The incident in which the "Linode problem" term was coined, more than 46K BTC were stolen in a security breach at Linode, including 43K from Bitcoinica's wallet alone.
Linode hasn't disclosed the exact scenario but it is believed that an employee's system was compromised remotely and that system had access to a back door that allowed administrative access to every Linode host.  With administrative access. wallet.dat's are vulnerable.

http://arstechnica.com/business/2012/03/bitcoins-worth-228000-stolen-from-customers-of-hacked-webhost/
http://bitcoinmagazine.net/the-bitcoinica-linode-theft-and-what-it-means-for-bitcoin/

There are all sorts of managed systems.  Most enterprise computing systems have administrative access for not only their systems in their data center but also for managing their employee's devices.  This might allow a thief, or rogue employee or contractor even to gain access to Bitcoins.
Even mobile devices could be totally vulnerable.
Answer: There lies the problem.  For a $100 a month, you can have a server administrator manage your Linode.  If his system gets compromised, you are now at risk for an attack.  In my case, I manage my entire server on my own.  I even went as far as setting up an SSH key for log in, so an attacker would have to get a hold of my system directly and find my ssh keys.  Considering I have all the latest antivirus software, firewall and common sense not to open up malicious email attachments, I should be fine.


New 'Scroll' Structured Websites

Question: What's this design style used by so many new websites called?  If anyone wants to edit this post to use a different link feel free.  I'm just wondering how the CSS and such works for websites that have scrolling 'frames' like this.  I heard that this sort of thing is often done in Wordpress.  Full disclosure:  I know next to nothing about web development.
Comment: possible duplicate of [What is the technical term (if one exists) for this kind of website design?](http://graphicdesign.stackexchange.com/questions/26879/what-is-the-technical-term-if-one-exists-for-this-kind-of-website-design)
Comment: My stock answer for this question: The style is called "annoying".
Comment: @DA01: that is hardly an objective comment ;) Scrolling is seen as the easiest way to navigate through content.
Comment: A scrollbar...? Or what specifically are you referring to? Keep in mind the coding of CSS is generally out of scope for this exchange.
Comment: could you post a screenshot on-site before it's gone forever?
Answer: I'm not sure this style has a particular name. I believe its origin could be in parallax scrolling sites, when you could use navigation buttons to "jump" to a portion of the the page that, as a section, used the whole screen height. They can also be referred to as Single Page sites, because most content is available on a single file.
Some examples of sites with similar color-block scrolling areas:

http://ala.ch/
http://www.endgame.com/ (parallax)
http://www.adveris.fr/
http://midyear.deakin.edu.au/#fee-freeze

Sites found on Awwwards
Answer: In the agencies I worked in, we always called them "One-Pager".
The coding of these pages is very easy since, as @Yisela mentioned, all the content is stored in one file (mostly). In my opinion it doesn´t really make a difference whether you use a CMS or not. And since most of these pages have static content and are for promotional stuff that doesn´t change too often, CMS aren´t in use that often.
Answer:
They are called «Single-Page Websites».
The Animation Effect you see is called: «Parallax Scrolling»
The appearance has absolutely nothing to do with WordPress. You can do this with any CMS, or with no CMS at all.

Things to think about when using this kind of design:

It's already overused
Altough it's quite fast to create because you don't have to think about a content navigation strategy it's a bit harder to extend these kind of pages.
The biggest drawback is that you only have one link for the whole content, so it's harder to share specific content.
Comment: I´m not so sure about 2 and 3, while I agree that it´s hard to extend these kind of pages, you can still have a content navigation and share content with an internal anchor.
But again, you mostly see these pages as microsites for projects or a presentation for agencies, so I think it is desired to start at the top and go down from there.
Comment: Sure. You can extend it with some anchor links. But entering a page somwhere down below isn't common sense, and can confuse users.

New 'Scroll' Structured Websites


Which measure of solar irradiance is needed to calculate the energy output of PV systems?

Question: According to "E = A * r * H * PR" global formula to estimate energy generated, the solar irradiance value is needed. I have Horizontal irradiance, Tilted irradiance, and Normal irradiance values but which measure of irradiance to use here? Or is it that all of these measures are used to calculate one value that is the total irradiance falling on a solar panel?
Comment: Does the tilted irradiance data tell you what angle it's tilted at? You'll want irradiance data that matches the angle of the panels you're doing the calculation for.
Comment: @LShaver. Yes, I do have the tilt angle of the panels. But is the "tilted irradiance" the only measure required here? Cause I have all of the mentioned measures and it doesn't make sense to use only "tilted irradiance".if it was like that then why is there a need to measure any of the other measures?
Comment: I presume if the tilted irradiance value is for a different angle than what you're looking for, you could use the horizontal and vertical irradiance values to make an approximation. Could also be useful for sun tracking arrays.
Comment: @LShaver. The tilted irradiance value that I have is for the angle that I require. That's no problem at all. Problem is how can I properly make the approximation of solar irradiance.
Comment: If you provide more details about the formula you're using and the data you have it may be possible to help answer your question. Please [edit](https://sustainability.stackexchange.com/posts/6855/edit) your question and provide a link to the data source, the units of the values, references, etc.
Answer: You don't want to do it this way.  It gets really messy and you need to take into account your climate, sunny hours per day through the year, time of year and so on.
Instead try looking up "solar potential atlas"  For Canada this is a big spreadsheet listing values by month for every city and village in the nation.  I'm sure there are equivalents for your country.
For example for me, if I have an array facing south sloped at my latitude, I get 1250 kWh per kW installed capacity.  So a 1 kW array generates for me about $100 worth of electricity per year.
Which value to use?  They are all going to be equivalent -- with a bit of trigonometry.
Normal in this case I assume means normal to the sunlight path.  You will have an additional factor of cos(d) where d is the angle difference between the angle of the sun and the angle of the PV array.  This varies by 47 degrees over the course of the year.  Rule of thumb:  Angle the array facing the equator tilted at an angle equal to your latitude from horizontal.  The sun wanders 23.5 degrees north and south of normal to this plane, which makes about a 5% difference.
A bigger change is due to the sun not always being to your south.  With stationary panels. the sun is at an angle to the east in the morning and west in the afternoon.
At my latitude (51 degrees) the horizontal incidence fluctuates by a factor of 10 between summer and winter, but for a latitude tilted panel it varies only by about a factor of 3.  In summer the early morning and later afternoon sun is lost because it's rising 40 degrees north of east and setting 40 degrees north of west.  The panel is self shading.
You would see a much larger difference if you used a tracking array, because it avoids this self shading.
(For me it wouldn't matter.  My max demand is in winter. A non tracking array gets about 80% of what a tracking array does.  My money is better spent on more cells, and bigger batteries.)
Comment: Solar atlas's like these http://globalsolaratlas.info/ does help to know the PV output as well as GHI, GTI etc at a place. But I'm actually trying to understand which measure irradiance (or how they are all used) to calculate the PV output rather than just knowing the output.


How can we distinguish "H-muet" or "H-aspiré"?

Question: Put the definite article before these words:

Habitude, Hache, Hanche, Hantise, Hardiesse, Harpe, Hasard,
  Hâte, Haut, Hauteur, Hélicoptère, Héros, Héroïne, Héroïsme,
  Hiérarchie, Historien, Horlogerie, Huile, Humanité, Humidité.
Answer: Unfortunately, there is no rule. Whether the h is considered a consonant (H aspiré, even though the letter itself is not sounded) or is transparent (H muet) is a case-by-case matter, partly driven by etymology. Even words of the same family are sometimes pronounced differently: l'héroïne [eʁɔin], l'héroïsme [eʁɔism] but le héros ['eʁo].
It's more common for words of Latin or Greek origin to have a H muet, and for words of Germanic or more recent origin to have a H aspiré, but this is by far not a hard-and-fast rule one way or another.
Wikipedia has a list of words with H aspiré, and that's as good as it gets.
There are also a few words where the h is expirated (H expiré): interjections such as ha, hé, etc. and onomatopoeia (e.g. hou [hu] or [u], the cry of the owl).
Answer: Je pensais à verser ceci de la part de http://forum.wordreference.com/showthread.php?t=109445.
De l'utilisateur Gil : Moyennant http://www.aidenet.com/scolaire/grammaire01.htm sur « h » :
Consonne muette quand on ne l'entend pas dans la prononciation du mot : l'homme.
Consonne aspirée lorsqu'elle fait prononcer la voyelle suivante avec une légère aspiration : la haine.
De l'utilisateur pktopp :
"He'ros must be pronounced with h aspire. Otherwise, its plural form "les he'ros" would be identical in pronunciation to "les z'eros".
Just found this quote in the DICTIONNAIRE DES DIFFICULTES DE LA LANGUE FRANCAISE (Larousse):
"héros se prononce avec h aspiré (pour éviter la liaison les-z-[h]éros [zéros]). Dans tous les dérivés (héroïne, héroïque, héroisme etc.) l'h est muet."
This book is a must have for any scholar of French. There is a large section dedicated to h aspiré . Just look under "H".
De l'utilisateur geve :
Found on http://membres.lycos.fr/clo7/grammaire/consonH.htm :
"Si héros a l'h muet, son féminin héroïne ainsi que tous ses dérivés (héroïque, héroïquement, héroïsme...) ne l'ont pas."
D'après www.sdv.fr/orthonet/pages/informations_p5.html, les mots d'origine germanique ont un H aspiré, tandis que les mots d'origine grecque ou latine ont un H muet.
De l'utilisateur jann :
Correct, liaison is forbidden when the following word begins with an aspirate H. The aspirate H itself is just as silent as the normal "unaspirated" H. The only thing that changes is whether or not you get to make élision & liaison.
H non-aspiré
le + honneur --> l'honneur (pronounced [lɔnœ:ʀ], with élision in the singular)
les + honneurs --> les honneurs (pronounced [lεzɔnœ:ʀ] or [le-] because you make the liaison in the plural)
There are many, many words like this: l'hôpital, l'homme, l'hiver, l'histoire, etc.
H aspiré
la + haine --> la haine (pronounced [laεn], no élision in the singular)
les + haines --> les haines (pronounced [lεeεn] or [le-], no liaison in the plural)
There are only a few dozen words like this : le haricot, le hasard, la honte, etc.
When you learn a new word that starts with an H, how do you know which kind of H it is? If you can look at the word and recognize that it's based on a Latin root, this might be a good sign that the H will be non-aspirate. But what if you don't know enough about Latin to be able to guess the root? In this case, you can look in a dictionary. If the word starts with an aspirate H, the pronunciation symbol for the word will start with an apostrophe, or you will see something like init. asp. written after the pronunciation.
In general, I think it's safe to say that the H at the beginning of a French word is usually not aspirate. Other than words borrowed from English (le hockey, le hold-up), there are really only a few dozen French words that start with aspirate H. You'll find a pretty good list in a white box at the bottom of http://www.ieeff.org/212phonology.htm, or see OlivierG's post above.
No, the French aspirate "H" of héros does not resemble the English H of "his". French does not have an H sound like English "his."
As I said in my post above, the aspirate H itself is just as silent as the normal "unaspirated" H. So the reason you cannot hear a difference between the two in conversation is because there isn't one! The only thing that changes is whether or not you get to make élision & liaison... and this, you will certainly hear.


What is the difference between shading and shadowing?

Question: Shading and shadowing are often mentioned in how to create realistic 3D graphics, but the distinction is not clear. Are both responsible for the generation of shadows, or do they refer to the same concept?
Answer: In simplified terms, shading controls how object's surface's brightness changes when the angle between its normal and light vector changes. Shadows are areas where the light cannot reach because it's occluded by other objects. So no, they both are not responsible for creating shadows.
Answer: The distinction is not clear mainly because the term "shading" is an extremely broad term. One of the first uses for programmable "shaders" in real-time graphics pipeline was computing illumination on vertices or pixels - close analogs to what an artist does when shading an object in a drawing for example.
Today it has come to encompass all calculations that figure into determining the final color of a fragment ("fragment/pixel shader"), or the final attribute values of a vertex ("vertex shader") or primitive ("geometry shader"), etc. Generally all programmable stages in the real-time graphics pipeline have come be called "shaders" whether they compute colors/illumination or not.
Shadowing likely just refers to shading work that determines the portion of direct light that is occluded with respect to a location on a surface. It can also reasonably refer to indirect illumination/occlusion.


How to access "Apps with usage access" setting on LG G3?

Question: I have an LG G3 with Android 5.0, but I can't find this setting.
I read it's in Privacy → Security, but the setting doesn't seem to be there:

Screenshot (click for larger variant)
Answer: It seems that LG removed the entry to the setting on LG G3. Whether it's accidental or not, it's unclear.
There are many reports stating the same issue:

on LG G3 Sub-Reddit

I have an app that asks me to go to "Apps with Usage Access". The app instructions tell me to go here: "Settings >> General >> Security >> Apps that access Usage Data". I am not exactly able to find it. My question is -- does your LG G3 with Lollipop have an option called "Apps that access Usage Data"?

by Mark on Google+

I'm using an LG G3 and since I got the Lollipop update I haven't been able to use the LAS app.
  I noticed the app (was) updated and requires to change 'Apps with usage access'. Unfortunately on my phone I don't see the option. I have installed on my Nexus 7 and made the required change and works perfectly again. Does anyone know how to change/access on a LG G3?

both on AndroidForums and AndroidCentral by same user (which has sligthly different issue)

Any time I restart my phone I get an error because of Smart Clean, it apparently resets itself & that interferes with Llama, and I need to go & toggle Smart Clean off again. Does anyone know if I can get to the screen below without going from an error message?

on AutomateIt's FAQ

Due to changes in Android Lollipop, In order for AutomateIt to monitor active apps it requires an explicit permission from the user. You can do that by going to your device Settings→Security and click on the "Apps with usage access option" (This should be the last item on the settings screen). On some devices, that option is not present (such as LG G3) and on those devices, the "Application State Trigger" cannot be supported.

on MobileSyrup Community

On stock Android, this can be found in Settings > Security > Apps with usage access. This is absent from the G3 running Lollipop.

on RescueTime's Blog

It appears that LG has pushed out a variant build of Android 5 missing an entire library that is part of the SDK specification for build level 21 (Android 5), the "android.app.usage" API.

Possible workaround:

Download an app that needs this setting to be switched on (e.g. based on the forum post, Llama).
Use custom ROM that implements this feature (e.g. based on Reddit's post, CyanogenMod 12)
Answer: You can access this setting by downloading Nova Launcher from the play store. Once installed hold down on any empty place until the add options coome up. Then click on activities and drag it to an empty place on screen. Now a list of activities will be displayed. Scroll down to settings and click on it. Now scroll down to apps with usage access. Hold it for a few seconds and the apps with usage access screen will open.
Answer: There's an app on Google Play called "QuickShortcutMaker" and it not only allows you to make shortcuts to anything sort of like Nova does, but also access any setting via a search function, including settings that are hidden in your ROM, for example if you're using a Chinese phone. That's how I get around hidden options on my ZTE.
Answer: On my LG K92 and Lenovo Duet (Chromebook), I had to search for "special app access". Then choose "usage access" and you'll be taken to a list of apps. Choose your app and change settings appropriately.


Cent OS 6.3: How to make places show up folders in tabbed versions (or at least not in a new window)

Question: I moved to CentOS 6.3 recently. The places application shows folders but each folder is shown in a new window. So if I go to 2 different folders and go deep in 3 sub folders, I will have six windows open. I thne end up closing all the folders and it becomes a problem. Is there  a way to open folders in tab
Comment: See: http://askubuntu.com/questions/121818/how-do-i-set-nautilus-to-use-same-window-on-double-click
Answer: I could not find a solution to this. So I have started using Konqueror. Places on Ubuntu 11.04 + seems to have these features but not on CentOS 6.3


Should Zeke's herald be more of a mandatory item for supports since the recent Life Steal nerf.

Question: I realize that this item does not build from any GP/10 items and requires you to build a second kindle gem including the one you would normally build for your Shurelya's Reverie, but since the recent nerf to life steal items, I see this item becoming more popular on supports.
Answer: I still this it's a situational item. Expensive as hell, it really only benefits that auto attacking champions on your team. Obviously if you're running Tristana, Renekton and Lee Sin (as an example), then yes, it's definitely something you should prioritize. However, items like Aegis and Reverie usually have more universal uses.
Despite support champions running the same basic GP/10 setup, there are times where it's good to deviate into items like will of the ancients, Zeke's or something else.
Comment: Starks does not exist anymore and has been reworked into Zeke's Herald.
Comment: Yep slight mistype, meant to say Zeke's there :)
Answer: its a great item for supports to build but the downside is it is very expensive and since most supports do not have a steady income of gold you wont be seeing this item until lategame since it helps only the adcarry maybe top maybe jungle, but adcarry the most it will not be as popular as shurelya's crown or the locket


Am I entitled to pay if my last day falls on a holiday?

Question: I worked for a large corporation in Texas, USA. I put in my two week notice and it just so happened that my last day fell on Good Friday. So, I was forced to turn all my equipment in on Thursday since no one would be there on Friday. I received my normal salary pay check. A few weeks later I got a letter stating that I was overpaid and would need to send a check equivalent to one day's pay back to them. At first I blew them off thinking it was ridiculous, but then I received a second letter where they stated they would turn me over to collections if they did not receive full payment in two weeks. I was just wondering if they have any grounds here. Or what US/Texas law says, if anything, about situations like this.
Comment: You may have signed a contract or endorsed a company handbook that includes this provision (though if you didn't receive severance pay, you are no longer receiving consideration to abide by their contract).  I have signed a permission to allow errors to be corrected from direct deposit.  But barring that, if they're sending you "nastygrams" about going to collections, send them a nastygram back demanding the documentation required by the Fair Debt Collections Practices Act.
Comment: What a bummer situation.  Yeah, tell them you need full documentation from them explaining why you wouldn't be paid for that holiday day.
Comment: Related on Workplace.SE, from the other perspective: [Standard for paying an employee when the last two days of notice are a holiday](https://workplace.stackexchange.com/q/36543/17663)
Comment: Did you have any accrued sick/vacation/PTO time left?  What became of any sick/vacation/PTO accrual?
Comment: When was the end of the pay period? And when was payday? I worked for a company that paid you on the day the pay period ended. They always had trouble with the last paycheck.
Answer: This question seems better suited for Law.SE, and I am not a lawyer, but here is my understanding of the situation.
Yes, they have the right to do this.  Texas is an "at-will" employment state, which basically means that, unless you have a specific contract in place or there is a company-wide policy in writing that states otherwise, you can be terminated at any time with or without cause.
If they terminate you without cause, you can request/appeal for Unemployment benefits.  This would apply if you are considered to have been "discharged" (terminated without cause).  Your case, however, is addressed specifically on the website of the Texas Workforce Commission:

If the employee gives notice of intent to resign by a definite date two weeks or less in the future and you accept the notice early at your convenience, it will be regarded as a resignation, not a discharge.

Again, if there is a company-wide policy in writing regarding how two-week notices and/or holiday pay are handled for resigning employees, you may have a leg to stand on in a UI claim for this single day's pay (assuming things get that far).  Otherwise, they have every right to come after you for the extra amount.
Comment: But can they retroactively change the date they accepted the notice? Until the letter claiming they overpaid, everything everyone did was consistent with a termination date of the Friday.
Comment: @Ganesh I don't necessarily agree.  Clearly, the employer at some point communicated to the employee that the final day of employment would be Thursday, since all of the equipment had to be turned in on that date. I suspect that the timing of that particular communication might factor in here.
Comment: I don't think turning in the equipment on the most convenient day automatically implies the end of employment, particularly if the stated reason was simply that nobody would be around to receive it the next day. But I'm not used to at-will employment.
Answer: Did you work the day in question?  No.  So you are not entitled to pay.
They are in the right.  However, if you do send them the check back it is likely your W-2 will reflect that you were paid for Good Friday.  Most payroll software makes it very hard to undo a paycheck.
If it was me, I would ask for an amended paycheck for this reason. "Yes, you are correct I did not work that day so I do not deserve to be paid.  However, I would need a amended pay stub reflecting that I did not receive income for that day, then I would be happy to pay back any extra monies I received."
Something like that will probably end it right there.
If they do send it to collections, expect the collection agent to lie and cheat.  They will promise you things with no intention of delivery.  Do not send them any money until you have all the things you desire up front.
You could also ignore it.  A friend of mine received a signing bonus with a one year minimum employment condition.  He left 5 months later.  Same kind of letter and the collections agent portrayed himself as a lawyer, and promised him he won all kinds of similar cases in court, yada, yada, yada.  Five years later, he is still waiting for the court notice.  Nothing came of it, despite being about $5k.  I doubt they will come after you for one day's pay.
Comment: Nobody works on a paid holiday.  You're implying that nobody is entitled to holiday pay, which is obviously false.
Comment: @PeteB. If the company agreed to give OP holidays with full pay as a benefit, as is common for salaried workers in the US, then OP should be entitled to that benefit until their employment ends.
Comment: "Did you work the day in question": arguably the OP did. Following a broad custom of two weeks notice, OP gave a termination date on a Friday. The company accepted this. Later, for the convenience of the company, OP returned equipment on Thursday. The OP may claim they were available, to work as directed on the Friday. OP was apparently salaried, so I suppose another approach is to prorate the holidays elapsed YTD over the holiday total to see if they were above or below the running average at end day. That may or may not work out to the OPS advantage though...
Comment: Your logic is twisted.  Do people not work on holidays and not get paid?  Yes. In the same company some are paid and some are not.  It is not right, but a benefit.  A very large difference.  De'Morgan's theorem is your friend.
Comment: Most lawyers will not bother with litigation for suits less than $10k, which explains your friend's situation. OP could most likely ignore this as well if they don't mind dealing with collections agents harassing them for the next 7 years.
Comment: Re the W-2. The company will most likely correct at least box 3 & 5 which are social security and medicare wages, to lower their tax obligation. If this happens in the same calendar year as when the "incorrect" paycheck was issued they will likely update box 1, that is the start of income tax. If the correction is done in a later calendar year, they are not allowed to change box 1. Meaning you will pay income tax on money already given back. :(


Cryptography and Coding Theory

Question: What is the difference between Cryptography and Coding Theory?
What books are good books on these topics? Especially from the  algebraic viewpoint.
Answer: Cryptography: Here is the essence of cryptography (both sides of the story).  I have some information, and it's encoded in a text file.  You really want to know what it says, but I can't let you do that.  So what happens is I'm going to try to translate it into my own secret language that I can share with my pals, but not with you.  Now, you want to do whatever you can to obtain and read my message.  Once you have the message you have some different things.  You can try to work backwards through my encoding scheme (if you know it), or you could try every possible decoding scheme until you find one that makes sense.  What you're doing here is called cryptanalysis.
Coding Theory: I have some information, in the form of a binary string (a sequence of 0's and 1's) that I want to store for a long time on my hard drive.  It's, like, a really long string.  But I'm pretty sure my hard drive is a safe place to store it, so we can take away some of the redundancy.  This compresses the file, and makes it easier to store.
Now, I want to take that file, and send it over the internet, but the connection isn't too good - it's a noisy channel.  How can I make sure that you receive the correct file? I can do this by adding redundancy - finding an efficient way to send my message with the following property:  If some percentage of the bits get "flipped" (some 0's turn into 1's and vice versa) when I send the message, you'll still be able to recognize what I said.
Comment: Thank the answer is very clear
Answer: There are many other excellent (both theoretical and applied in both these areas and there are combined books too), but these should get you started.
Cryptography Books
A Course in Number Theory and Cryptography, Neal Koblitz
Algebraic Aspects of Cryptography, Neal Koblitz
The mathematics of ciphers: number theory and RSA cryptography, Coutinho S C, Severino Collier Coutinho
An Introduction to Cryptography, Richard A. Mollin
Introduction to Cryptography with Coding Theory (2nd Edition) by Wade Trappe and Lawrence C. Washington (Jul 25, 2005)
Coding Theory
Introduction to Coding Theory (Graduate Texts in Mathematics), J.H. van Lint (Author)
Information and Coding Theory (Springer Undergraduate Mathematics Series), Gareth A. Jones (Author), J.Mary Jones (Author)
Coding Theory and Cryptography: The Essentials, Second Edition (Chapman & Hall/CRC Pure and Applied Mathematics) by D.C. Hankerson, Gary Hoffman, D.A. Leonard and Charles C. Lindner (Aug 4, 2000)
I can add more applied books to each list and there are many, so just ask.
Regards -A
Comment: Thanks this is very helpful for me
Answer: Cryptography is concerned with secure, Coding Theory with efficient, communication.
Comment: I would add that coding theory also deals with reliable communication.
Answer: Cryptography is a specific art of secret communication where the shape of the signal to be sent is not of main importance. The communication channel is also assumed to be secured, e.g, by wired cables or the existence of secret communication is public.
Another art of secret communication where the existence of the secret communication is not shared by the third parties is called steganograpy.
The former one uses mainly number theory whereas the latter one uses mainly reverse-coding-theory. I call it as reverse coding theory because the theory from channel coding is not directly applicable and should be a bit changed.
The art of science which targets at exposing the existence of secret messages is called steganalysis and uses mainly the theory from detection/classification theory whereas the the art of science which targets at decrypting the secret messages is called cryptanalysis and uses mainly the theory from probability and number theory.
The coding theory is divided into two subsections. One of them is called source coding and the other is called channel coding.It is mostly attributed to channel coding because it is wider and more comprehensive in my opinion.
Source coding deals with coding a given source with least possible number of bits. It is also known as lossless compression. The limits of this coding scheme is given By Shanon. No source coding sheme can encode a given source below the entropy of that source with an error free decoding option. The entropy of a source  $$H(X)=\sum_i p(x_i) \log \frac{1}{p(x_i)}$$
is also known as the average information and for a given cardinality, random sources maximize it.
Channel coding on the other hand is opposite to the idea of soure coding. While source coding removes the redunancy to reach least possible bits to represent the source, channel coding aims at introducing redundancy in a clever way to provide error free communication over a noisy channel. The main aim here is to provide some channel codes which can achieve the chanel capacity which is defined between the transmit $X$ and received signal $Y$ as
$$C=\max_{p_x}I(X,Y)$$
where $I$ is called mutual information. There exist no channel codes which can transfer more number of bits from a noisy channel having a rate $R$ which is greater than $C$. As it can be seen there is an analogy between source and channel coding as well as cryptography and steganograpy although the theories that are used are changing from one to the other.
Comment: Thank the answer is very clear
Comment: What knowledge is required for Coding Theory?
Answer: As to undergraduate textbooks, Trappe/Washington is a good one that covers both coding theory and cryptography (with more emphasis on cryptography).
To appreciate the difference, look at Claude Shannon's seminal papers on Cryptography
and on the foundations of Coding Theory.
Answer: this book is useful too : Designs and their Codes, J. D. Key
Comment: How does this answer the question?
Comment: @Ram: It addresses the request for books, I assume.
Comment: @Ram: I looked it up on amazon.com and added the link
Comment: @robjohn when I wrote my comment there is no link, it seems he added (link) later.
Comment: The book appears as if it might be useful. Would the downvoter care to comment?

Cryptography and Coding Theory


Using the API directly from JavaScript

Question: Is there any way I can use the API directly from JavaScript without any Server side proxy? I know of the inter-domain restrictions, but can we do it somehow in case of facebook API right?
Answer: You can do this by making a JSONP request. This works by returning the results of a query in a

Using the API directly from JavaScript


2008 Audi a6 anyway to play music from smartphone

Question: Is there any aux inputs on a 2008 Audi a6 I'm going to get one tomorrow and at the dealership, I never checked online I came across a few places saying it does and it doesn't does anyone know if it does? or if I can add Bluetooth/aux so I can play my own music
Comment: You might review https://mechanics.stackexchange.com/questions/33512/2008-audi-a6-how-to-play-music-via-smartphone?rq=1 and  https://mechanics.stackexchange.com/questions/8522/2008-audi-a4-quattro-3-2l-ipod-dock-and-music?rq=1
Answer: Your 2008 A6 should be able to pair a phone using bluetooth.  The owner's manual is built into the infotainment console for reference on how to do this.
If that doesn't allow music streaming, there are I beleive TWO external AV input jacks to connect.
Answer: The built in Bluetooth won't allow the playback of music/media - it doesn't have the appropriate BT profiles and will only connect for phone purposes. Audi didn't add that in until 2012-13, and yes it's extremely annoying!
If you've got the MMI 3G with the Audi Music Interface connector in the glovebox you should be able to get a Bluetooth adapter that connects to that port and in turn to the phone via BT (this is what I have in my RS5). This doesn't work for pre-09 cars that have the MMI 2G though IIRC so you'll want to check which variant you have before ordering any kit.
Not sure if it holds true for all adapters but at least for mine it's a "dumb" connection - mirroring the functionality of a plain AUX IN lead so you can't control playback or get track info etc this way so you still have to use the phone to select and play tracks.
Answer: I think on the earlier Audi's they had aux inputs but it was a special lead that went into the back of the head unit.
If your lucky the lead maybe in the center console between the seats


Where is the file Elite Dangerous stores the controls?

Question: I'd like to easily backup my controls in Elite: Dangerous. Does anyone know where the controls are stored, or a way to find out? Thanks!
Comment: I don't really play the game but it would be in a file like C:\program files\elite dangerous\cfg\elite.cfg or similar cfg file so be sure to check your install directory and copy over any cfg file.
Comment: Thanks, but I've looked through all kinds of .cfg and .xml files and can't find where the settings are stored. So I was wondering if someone else had found them by now. :)
Answer: I have found them here for the Beta 1.02:
C:\Users\USERNAME\AppData\Local\Frontier Developments\Elite Dangerous\Options\Bindings\
There are 2 files of interest: "Custom.binds" and "StartPreset.start"
Answer: If you copy the Custom.binds file to MyName.binds (or something) it will appear in the drop-down menu for you to choose from.
Comment: I just tried this in 1.4 and you will have to do one more step. In the file you will need to change the value of PresetName in the root tag of the XML to what you want to show in the drop down.
Answer: I think I found them! I don't know if they added them since the beta came out, or what. But It looks like custom bindings are saved in a file here: \Users\USER\Local\Frontier Developments\Elite Dangerous\Options\Bindings
Answer: On the Mac they are stored in : ~/Library/Application Support/Frontier Developments/Elite Dangerous/Options/Bindings
Where ~/ is your user folder /Users/<your_user_name>/Library/Application Supp...
Answer: Found it a bit silly i couldnt just add comments for clarification but can provide a new answer. Regardless, just to update / concur:
Elite Dangerous Horizons V2018.12.17.190809
Location:

C:\Users\USERNAME\AppData\Local\Frontier Developments\Elite
  Dangerous\Options\Bindings\

AS stated previously;
"There are 2 files of interest: "Custom.binds" and "StartPreset.start""
But you dont need to do anything with the startpreset file, when in-game that file will update to whatever you last 'loaded'.
When COPYING to make additional config profiles, as stated in a comment by GERT. You need to edit the PRESETNAME inside the file as well as the actual file name.
What i noticed was that the baseline Custom.binds file didnt have that option but i had an extra file called custom.3.0.binds which did have a preset.
So copy that one, edit the file name and preset inside the file, save and reload your game.
I did all this in testing setup for a 3D mouse (3Dconnexion) for very fine controls esp for docking [which i was only able to get working by using ControlMyJoystick as by default this does not work well at all].
Answer: On Linux (Ubuntu) I found them under:
steamapps/compatdata/359320/pfx/drive_c/users/steamuser/AppData/Local/Frontier Developments/Elite Dangerous/Options/Bindings

The location of steamapps depends on your steam library location.


How much of the Shuttle was physically realized in the simulator?

Question: How much of the Shuttle physically existed in the simulator?  Was it just the flight deck?  Or were the mid-deck, lower equipment bay, and/or payload bay also included?
Comment: A small point, but, in the spirit of keeping stackexchange technically rigorous, suggest the title question be changed such that the word "Shuttle" be replaced by the phrase "Space Shuttle Orbiter".  Also suggest the body of subject post be similarly modified.
Comment: Meh.  Even if one were to interpret "Shuttle" as the entire launch stack, the premise that the simulator realizes only part of it would still be accurate.
Answer: Note: there were a lot of training simulators. This answer concentrates on the Shuttle Mission Simulators.  There were mockup type simulators like the Crew Compartment Trainer (CCT) that replicated the crew module interior very well. They weren't computer-driven though - most of the switches did nothing.  Here's the CCT set up in a museum.

Image source

There were two different styles of "bases" or training devices in the two buildings that constituted the Shuttle Mission Simulator facility.  Each style provided different parts of the Orbiter crew module for training.
The Motion Base (of which there was only one example) provided only the forward portion of the flight deck in a high-fidelity manner.  In other words, everything seen and touched by the pilot and commander was flight-like.  There were no aft or aft side panels, although the Display Electronics Unit (DEU) 4 and a keyboard was provided for the use of MS-1. This panel was not flight-like.
External view of the Motion Base

Internal view of the MS-2 and MS-1 seat positions in the Motion Base. You can see how the flight-like interior stops above and slightly behind the pilot and commander's heads. You can also see DEU 4 and its keyboard on the far right wall of the simulator.

The Fixed Base and GNS simulators provided a complete flight deck interior - forward, side, and aft crew station panels were all provided.  They provided a mid-deck which was volumetrically and visually unrealistic but in which were mounted flight-like panels, lockers, and the galley.  There was no airlock volume or Lower Equipment Bay volume simulated in these simulators, although airlock control panels were provided.
This is an exterior picture of the GNS (the Fixed Base was similar).

This picture shows how in these "bases" the flight-like interior continued past the pilot and commander seats. The left side wall is shown.

This picture shows some of the mid-deck panels with the unrealistic walls.

Before the GNS was retrofitted into a fully capable simulator, the Motion Base was provided with an aft crew station - but it was located in another room, and the Motion Base had to be locked in position, and an access bridge lowered.
There was a Waste Collection System (space toilet) simulation/training room in the facility, but it was not directly connected to any of the simulators. It was located between the Motion and Fixed Bases.
The payload bay was simulated only  - you could see it out of the simulated aft windows, and interact with objects in the view.
Example of payload bay view out crew station aft windows

Picture credits: Either NASA PAO, or personal shots.
Reference: I worked there
Comment: I was at the VMS once, it was freaking awesome. @ScottSeidman
Comment: `+n!` for you on this one! I've just asked [Was a real Space Shuttle ever used as a really big simulator?](https://space.stackexchange.com/q/38759/12102)
Comment: Nit "*There were two different styles of "bases" or training devices in the two buildings*" Both the "Motion Base" and "Fixed Base" simulators were housed next to each other in Building 5 at JSC.
Comment: Yes, and the GNS was in bldg 35, so what I wrote is 100% correct.
Comment: There's also the Vertical Motion Simulator at Moffett Field.  https://www.youtube.com/watch?v=0WaiAyU-3mU.  My understanding is that every crew was trained for a certain aspect of landing on this.  It's a tilt simulator on a building-sized XYZ mover.  I've been in it (while stationary), and can confirm that they had signed photos from many mission crews who have used it outside the entrance to the cab.
Answer: One of the Space Shuttle simulators flew
The Shuttle Training Aircraft was a Grumman Gulfstream II that was heavily modified so that pilots could train to land the shuttle in an aircraft that had similar flight characteristics to the real shuttle (when landing).  It extended the gear and ran the engines with the thrust reversers engaged so that it could approach as steeply as the real shuttle did without overspeeding, and it was modified to withstand the high aerodynamic stresses involved.

Image downloaded from Wikipedia (source: NASA, public domain)
The student astronaut flew in the left seat, which had shuttle controls.  The instructor/safety pilot flew in the right seat, which had jet controls.

Image downloaded from Wikipedia (source: NASA, public domain)
Special software controlled the jet to make it fly like the Shuttle.  From Modified Jet Stands in for Landing Orbiter (NASA):

The wing and engine modifications are the tools that a set of computers inside the aircraft use to make the shuttle pilots feel like they are flying an unpowered spacecraft. That means the pilots are in charge, but the computers are in control.
When the astronaut pulls the control stick back, for example, the computer decides how a real orbiter would react. Then the computer moves the wing and tail to make the STA act the same way. The movement takes a scant 50 milliseconds to occur, though, so the pilot senses no delay.
"The computer controls the airspeed and the auto-throttle controls the engines," explained Alyson Hickey, a flight simulations engineer aboard the STA.

There's a lot more about this amazing jet in the article.


What is Quantum Phase Estimation in Shor's Algorithm?

Question: While I'm studying Algorithm, I couldn't understand what Quantum Phase Estimation is. And I heard there is relation between Phase-Kickback and Quantum Phase Estimation. I wonder what it is. Also, I'm not sure what this is and how it works within the algorithm. I would like to learn from the mathematical point of view and the conceptual part.
Answer: Phase estimation is the process by which you are given a controlled-$U$ unitary, and a state that you are promised is an eigenvector of $U$ with eigenvalue $e^{2\pi ix/2^t}$, then you can use a $t$-qubit register to affect the change
$$
|0\rangle^{\otimes t}|u\rangle\mapsto|y\rangle|u\rangle.
$$
If $x$ is in integer, then the outcome is guaranteed to be $y=x$. If $x$ is not an integer, $y$ is, with high probability, the closest integer to $x$.
The phase-kickback is the way that we get something, apparently on the second register (i.e. the $|u\rangle$ being acted upon by $U$) to change the first register. In effect, this is making use of the difference between global phase (as it would be for $U$) and relative phase in a superposition (which is what you actually get when you use controlled-$U$).
Before I go into the detailed mathematics, what have you read so far (as this is standard in all texts)? What is it you don't understand?
Answer: If you want to learn more generally about phase estimation, the book I am helping write has a whole chapter on it, Learn Quantum Computing with Python and Q# (chapter 8).
Ping me here or via email and I can get you a discount code!


Export DXF Issue in QGIS?

Question: I got the shapefiles in QGIS and transformed them to UTM NAD83 from WGS84, then tried to create a DXF of it so I could use it as an overlay in fieldgenius software for a topographic survey we're conducting. But the DXF created falls wayyyyy on the other side of the world compared to the partial survey I've already done in UTM NAD83. I tried using the DXF file back into QGIS and does the same.
It's my first time experimenting with it, does it lose it's coordinate system information? How can I bring back to right system?
Answer: I found that for a successful dxf export you must not enable 'on the fly' reprojection in order to have a project crs different from the data. The project has to have the same crs as your data. cp this issue: QGIS 2.14.3 export PostGIS layer to dxf issue
two tickets are on the way concerning the same issues:
https://hub.qgis.org/issues/14940
https://hub.qgis.org/issues/11988
the later of which describes what you have observed.

Export DXF Issue in QGIS?