... you have confirmed that you have not abandoned your incorrect (and actually quite ludicrous) version of heat transfer, which violates the Stefan-Boltzmann radiation law on its very face. ... [Jane Q. Public, 2014-09-15]

... or maybe we disagree about which variable to hold constant.

Instead of holding electrical heating power constant, Jane held the source's radiative power output constant. That held source temperature constant and forced electrical heating power to change. Solving this problem using both sets of boundary conditions shows that Jane's solution forces electrical heating power to drop by a factor of two after the shell is added.

These two sets of boundary conditions are very different, just like Neumann boundary conditions are different from Dirichlet boundary conditions. Upon hearing that a disagreement might be caused by holding different variables constant, a real skeptic might consider working the problem again while holding that other variable constant. But Jane can't even admit there's a difference between holding electrical heating power constant and holding the source's radiative power output constant. Jane even insists he held electrical heating power constant, despite the evidence.

So Jane won't solve this problem with the electrical heating power constant. That's unfortunate, because it's critical:

"... critical to the whole experiment is that, like the sun heating the surface of the Earth, there is energy being continuously pumped into the system from outside. ..."

1. Holding electrical heating power constant while adding an enclosing shell is like doubling CO2 while holding solar heating power constant, then calculating how much Earth's surface warms.

2. Holding source temperature constant while adding an enclosing shell is like doubling CO2 while holding Earth's surface temperature constant, then calculating how much solar heating power would have to drop to keep Earth's surface temperature constant.

Even if Jane doesn't want to solve that first problem, he should recognize that it's different from the second problem Jane actually solved.

To see this difference, solve a problem with Neumann boundary conditions:

"In thermodynamics, where a surface has a prescribed heat flux, such as a perfect insulator (where flux is zero) or an electrical component dissipating a known power."

... then solve the same problem with Dirichlet boundary conditions:

"In thermodynamics, where a surface is held at a fixed temperature.

Dr. Spencer's thought experiment placed Neumann boundary conditions on the source and Dirichlet boundary conditions on the chamber walls. Instead, Jane placed Dirichlet boundary conditions on the chamber walls and the source.

In other words, the electrical heating power is determined by drawing a boundary around the heat source:
power in = electrical heating power + radiative power in from the chamber walls
power out = radiative power out from the heat source

Since power in = power out:

electrical heating power + radiative power in from the chamber walls = radiative power out from the heat source

Right?

No. Not right. Since emissivity doesn't change the input required to heat source to achieve 150F is constant, regardless of where it comes from. But as long as the walls of the chamber are cooler than the source, NONE of the power comes from the chamber walls, because of that minus sign in the equation above. Nothing has changed in that respect, and that's what the Stefan-Boltzmann law requires. The only time that changes is if the walls are at an equal temperature, in which case heat transfer is 0 and you can begin to use "ambient" temperature as input. You are still supplying the same input power, you are just supplying it a different way. If the chamber walls were hotter than the central source, then heat transfer would be in the other direction (because the sign of the solution to the equation above changes), and only THEN are you getting net heat transfer TO the central sphere. ... [Jane Q. Public, 2014-09-15]

Note that conservation of energy through a boundary around the source leads directly to an equation describing the electrical power required to keep the source at temperature T1 inside chamber walls at temperature T4. This equation is valid for T1 > T4, T1 = T4, and T1 < T4. Jane might wonder why he can't derive a single equation which works for all these cases.

Again, warming the chamber walls is like partially closing the drain on a bathtub where water is flowing in at a constant rate. This raises the bathtub water level simply by reducing the water flow out. In exactly the same way, a source heated with constant electrical power warms when the chamber walls are warmed because that reduces the net power out.

... because T(p) < T(s), no matter now much of the radiation from P strikes S, no net amount is absorbed; it is all reflected, transmitted, or scattered according to S-B. ... [Jane Q. Public, 2014-09-04]

Are you REALLY the moron you make yourself out to be? NET radiation from a cooler surface that passes the boundary is reflected, transmitted, or scattered and passes right back out through the boundary. This is a corollary of the Stefan-Boltzmann radiation law, which states that NET heat transfer is always from hotter to cooler. ... by that same law, it just passes right back out again because the same NET amount of radiative power that crosses the boundary and intercepts the smaller sphere is either reflected, transmitted, or scattered. ... [Jane Q. Public, 2014-09-15]

... Since the chamber walls are COOLER than the heat source, radiative power from the chamber walls is not absorbed by the heat source. ... [Jane Q. Public, 2014-09-15]

Hopefully these are just more badly-worded sentences because they all require absorptivity = 0. But these gray bodies have emissivity = absorptivity = 0.11. Furthermore, the gray body equation has to reduce to the black body equation for emissivity = absorptivity = 1. In that case there are no reflections, just absorption.

Once again, a heated blackbody source is heated by constant electrical power flowing in. Blackbody cold walls at 0F (T4 = 255.4K) also radiate power in. The source at 150F (T1 = 338.7K) radiates power out. At steady-state, power in = power out:

electricity + (s)*T4^4 = (s)*T1^4 (Eq. 1J.2)

Since Jane's proposed equation is missing the "(s)*T4^4" term, it doesn't reduce to this simpler Eq. 1J.2 for blackbodies where (e) = 1. So it's wrong.

It's also ironic that Jane claims to account for reflections, because:

... Calculate initial (denoted by "i") heat transfer from heat source to chamber wall. We are doing this only to check our work later. Using the canonical heat transfer equation for gray bodies...
p(i) = (e)(s) * ( T1^4 - T4^4 ) ... [Jane Q. Public, 2014-09-10]

... You are ignoring (e*s) * (Ta^4 - Tb^4). Anything other than what I described does not add up. ... (e*s) * (Ta^4 - Tb^4) ... [Jane Q. Public, 2014-09-15]

That equation is true for blackbodies with emissivity = 1, which is why it's consistent with my equation 1.

But for gray bodies it's just an approximation because it ignores reflections. After obviously failing to explain that we need to account for reflections, I decided to agree to disagree. For two gray bodies interacting with small view factors (e.g. Earth's tiny view factor of the Sun) reflections can be safely neglected. But the chamber wall completely encloses the source, so its view factor is 1. That's why MIT's equation is more accurate here: it accounts for reflections.

Again, here's MIT's equation using Jane's new variable names:

p(i) = (s)*(T1^4 - T4^4)/(1/(e) + 1/(e) - 1) (Eq. 2J.2)

Luckily this disagreement isn't important because it just shifts the emissivity values. We can translate because plugging emissivity = 0.058 into Jane's equation yields the same net heat transfer as MIT's equation with emissivity = 0.11. Furthermore, my black and gray body calculations yielded identical enclosed steady-state temperatures, so those don't depend on emissivity.

But after using Jane's equation in pointless attempts to illustrate more fundamental problems in Jane's analysis, I wanted to stress once again that MIT's equation is more appropriate for enclosing chamber walls because it accounts for reflections.

It depends on your design goals.

In Asimov's story universe, the Three Laws are so deeply embedded in robotics technology they can't be circumvented by subsequent designers -- not without throwing out all subsequent robotics technology developments and starting over again from scratch. That's one heck of a tall order. Complaining about a corner case in which the system doesn't work as you'd like after they achieved that seems like nitpicking.

We do know that *more* sophisticated robots can designed make more subtle ethical systems -- which is another sign of a robust fundamental design. The simplistic ethics is what subsequent designers get when they get "for free" when they use an off-the-shelf positronic brain to control a welding robot or bread-slicing machine.

Think of the basic positronic brain design as a design framework. One of the hallmarks of a robust framework is that easy things are easy and hard things are possible. By simply using the positronic framework the designers of the bread slicing machine don't have to figure out all the ways the machine might slice a person's fingers off. The framework takes care of that for them.

I thinkyou mean:

"It isnot exactlyEnglish, but definitelyin theGermanic family."

It isokay noteveryone is goodat grammar.

I don't think you've really grasped Apple's design sensibility. Job one for the designers is to deliver a product that consumers want but can't get anywhere else.

The "camera bulge" may be a huge blunder, or it may be just a tempest in a teapot. The real test will be the user's reactions when they hold the device in their hand, or see it in another user's hand. If the reaction is "I want it", the designers have done their job. If it's "Holy cow, look at that camera bulge," then it's a screw-up.

The thinness thing hasn't been about practicality for a long, long time; certainly not since smartphones got thinner than 12mm or so. They always been practical things the could have given us other than thinness, but what they want you to do is pick up the phone and say, "Look how thin the made this!" The marketing value of that is that it signals that you've got the latest and greatest device. There's a limit of course, and maybe we're at it now. Otherwise we'll be carrying devices in ten years that look like big razor blades.

At some point in your life you'll probably have seen so many latest and greatest things that having the latest and greatest isn't important to you any longer. That's when know you've aged out of the demographic designers care about.

Well, we are, on the aggrigate, delusional and self aggrandizing.

Very, very delusional and very, very self aggrandizing. You see it in every topic.

I think Australia just isn't big enough. It doesn't represent enough money or enough people. It's small enough that the gatekeepers might not give a damn. Screwing over the whole continent is not that big of a loss for them.

> They are demanding it: see "Should Open-Source" in the title.

You are a delusional idiot.

"Should" does not imply or indicate a demand.

It's time to step out of the Cupertino reality distortion field.

You fanboys are like a bunch of fundies.

> Apple, and others, stopped using the "truly free" gcc because GPL v3 became quite restrictive.

There's nothing in there that should scare off anyone. If someone is bothered by the GPL3 in a project like C++ compiler, then you should be very suspicious of their motives. They clearly aren't interested in playing nice or being a good citizen.

They clearly want to be free to f*ck you over later.

Why "give" anything? The first one that delivers should win. Competitors should not be prematurely removed from the race just because of rampant cronyism.

It's pretty easy to argue that a bloated corporate behemoth could be lagging behind an upstart startup.

That's not uncommon in tech.

I've heard Apple uses it....

"It's not enough getting a free ride off of developers building great software, we want to shove our roadmap down their throats and get them to work harder for us â" without having to pay for it, of course."

Looks more like "We want to figure out how best to coordinate and share that portion of the work that the people whom we pay to develop software for us, do on free software." (Though they're not using that dangerous word "free", of course.)

"Free" or "open source" doesn't mean no one is getting paid to develop it.

Every one of the links you have posted comes from a mainstream Aussie media outlet, when those stories stop appearing you have a real corruption problem. The NSW ICAC judicial inquiry has forced the resignation of at least a dozen MP's who took illegal donations from property developers and is still going strong. Now think about real oppression (say) Mugabe or Saddam, they tow the line or risk summary execution.

Internet snooping by cops is a double edged sword, sure it can be used as a tool of oppression (if the political climate is ripe) but it has also been used to solve some high profile murder/rape cases. In the Jill Megan (sic?) case the cops didn't spy on anyone, they simply explained the situation to the banks (on the weekend) and the banks voluntarily gave them what they needed to track the bastard down.

Disclaimer: I have a female cousin who has served in the Victorian police for over 3 decades. I'm not claiming all Aussie cops are saints, but certainly the vast majority have their heart in the right place and are doing a tough job as best they can.

I think you are entirely correct about the difficulty in predicting disruptive technologies. But there's an angle here I think you may not have considered: the possibility that just the cultural values and norms of the distant future might be so alien to us that readers wouldn't identify with future people or want to read about them and their problems.

Imagine a reader in 1940 reading a science fiction story which accurately predicted 2014. The idea that there would be women working who aren't just trolling for husbands would strike him as bizarre and not very credible. An openly transgendered character who wasn't immediately arrested or put into a mental hospital would be beyond belief.

Now send that story back another 100 years, to 1840. The idea that blacks should be treated equally and even supervise whites would be shocking. Go back to 1740. The irrelevance of the hereditary aristocracy would be difficult to accept. In 1640, the secularism of 2014 society and would be distasteful, and the relative lack of censorship would be seen as radical (Milton wouldn't publish his landmark essay Aereopagitica for another four years). Hop back to 1340. A society in which the majority of the population is not tied to the land would be viewed as chaos, positively diseased. But in seven years the BLack Death will arrive in Western Europe. Displaced serfs will wander the land, taking wage work for the first time in places where the find labor shortages. This is a shocking change that will resist all attempts at reversal.

This is all quite apart from the changes in values that have been forced upon us by scientific and technological advancement. The ethical issues discussed in a modern text on medical ethics would probably have frozen Edgar Allen Poe's blood.

I think it's just as hard to predict how the values and norms of society will change in five hundred years as it is to accurately predict future technology. My guess is that while we'd find things to admire in that future society, overall we would find it disturbing, possibly even evil according to our values. I say this not out of pessimism, but out my observation that we're historically parochial. We think implicitly like Karl Marx -- that there's a point where history comes to an end. Only we happen to think that point is *now*. Yes, we understand that our technology will change radically, but we assume our culture will not.

... Since emissivity doesn't change the input required to heat source to achieve 150F is constant, regardless of where it comes from. But as long as the walls of the chamber are cooler than the source, NONE of the power comes from the chamber walls... [Jane Q. Public, 2014-09-15]

But if the chamber walls are also at 150F, they're not cooler than the source and the input required to heat the source to 150F is zero.

... do you still maintain that after the enclosing passive sphere is inserted, the central heat source raises in temperature to approximately 241 degrees F? You haven't said anything about that in a while, so I'm just checking. [Jane Q. Public, 2014-09-15]

Once again, if the electrical heating power is held constant, the heat source has to warm. Once agin, Jane's heat source keeps the source temperature constant by halving its electrical heating power. Jane/Lonny Eachus might ask himself why his required electrical heating power goes down by a factor of two after the enclosing shell is added.