## Search found 1437 matches

- Fri Apr 13, 2012 12:56 pm UTC
- Forum: Science
- Topic: Nuclear fusion!
- Replies:
**64** - Views:
**13166**

### Re: Nuclear fusion!

And considering that computing power is dirt cheap, and turbines and buildings are not new tech, a commercial reactor would probably cost on the order of a mid-sized coal plant -- if not less. It's this sentence that makes you seem to be vastly underestimating the difficulties and costs in building...

- Thu Apr 12, 2012 5:56 pm UTC
- Forum: Science
- Topic: Nuclear fusion!
- Replies:
**64** - Views:
**13166**

### Re: Nuclear fusion!

They're expensive because they're research projects, and rather than a bunch of certified engineers managing them, they have scores of highly-trained PhD-level research scientists working on them Fission plants aren't all research projects and they aren't cheap to build, even the ones managed by ce...

- Thu Apr 12, 2012 5:47 pm UTC
- Forum: Science
- Topic: Nuclear fusion!
- Replies:
**64** - Views:
**13166**

### Re: Nuclear fusion!

All you need are magnets, a turbine, a building, and really good computers. And considering that computing power is dirt cheap, and turbines and buildings are not new tech, a commercial reactor would probably cost on the order of a mid-sized coal plant -- if not less. By that logic, the LHC should ...

- Thu Apr 12, 2012 5:35 pm UTC
- Forum: Mathematics
- Topic: Finding points on a perimeter
- Replies:
**13** - Views:
**2348**

### Re: Finding points on a perimeter

As for the three examples above, I still like the hourgalss one the best, which is fascinating since it is the most difficult to compute. I'm going to push back on the word "compute". It's not the process of computation that is the problem in all likelihood. The problem is that you have t...

- Thu Apr 12, 2012 2:14 pm UTC
- Forum: Science
- Topic: Nuclear fusion!
- Replies:
**64** - Views:
**13166**

### Re: Nuclear fusion!

It's worth noting that all of the above mentioned benefits and more were claimed for fission power. In the 50's and 60's the expectation was that electricity from fission plants would be literally "too cheap to meter." And no one started thinking seriously about the problems of nuclear wa...

- Wed Apr 11, 2012 6:46 pm UTC
- Forum: Science
- Topic: Nuclear fusion!
- Replies:
**64** - Views:
**13166**

### Re: Nuclear fusion!

In addition to being abundant, fusion would be inexpensive to deploy. You could build a reactor in a third world country, operate it very cheaply, and provide power to the citizens without any fear that the local government would attempt to use it to build a bomb. Reactors would also be very small,...

- Wed Apr 11, 2012 5:55 pm UTC
- Forum: Science
- Topic: Nuclear fusion!
- Replies:
**64** - Views:
**13166**

### Re: Nuclear fusion!

In addition, fusion reactors cannot be used to generate weapons-grade materials. There is no risk of a catastrophic event happening in a fusion reactor -- no chance of meltdown. There are very few radioactive byproducts; although the reactor housing becomes radioactive over time, it would, in princi...

- Wed Apr 11, 2012 4:12 pm UTC
- Forum: Mathematics
- Topic: Efficient method to find lattice points
- Replies:
**4** - Views:
**2077**

### Re: Efficient method to find lattice points

Is this homework? Regardless, I'll throw out what I've thought up really quickly. So you have a normal vector, n. From this you can define a plane by finding vectors orthogonal to n (and to each other). These m vectors form a basis. Call them b_1, b_2, ..., b_m. So, any point on the plane can be wri...

- Wed Apr 11, 2012 2:44 pm UTC
- Forum: Science
- Topic: Why do airplanes need wings?
- Replies:
**66** - Views:
**12961**

### Re: Why do airplanes need wings?

Flow control has a number of purposes, generally pertaining to increasing flight envelope, or increasing controllability near the boundaries of the flight envelope. This includes maintaining controllability at high angles of attack, increasing redundancy in the event of actuator failure, delaying fl...

- Tue Apr 10, 2012 7:41 pm UTC
- Forum: Mathematics
- Topic: Batting averages and the elusiveness of .249
- Replies:
**8** - Views:
**2381**

### Re: Batting averages and the elusiveness of .249

That is the reason why I rounded 666,66... up to get 667, as 1/667 < 0.0015. Also, no batter will ever have an average of 0.001. His ass would quite simply be sent back down to the minors well before that point! I am not sure how to include this in the analysis. :lol: Oh you rounded up the other nu...

- Tue Apr 10, 2012 7:02 pm UTC
- Forum: General
- Topic: Living alone: anecdotes and such
- Replies:
**69** - Views:
**13806**

### Re: Living alone: anecdotes and such

If someone tells a Polish joke, that doesn't make them Polish, does it? No, but it likely makes them racist. And no, it's not just because of the slapping. It's not racist because Polish isn't a race. It's a nationality. And us Poles usually don't care, because we're too busy doing awesome things l...

- Tue Apr 10, 2012 6:57 pm UTC
- Forum: Mathematics
- Topic: Batting averages and the elusiveness of .249
- Replies:
**8** - Views:
**2381**

### Re: Batting averages and the elusiveness of .249

.0015 rounded up should surely be .002, no?

Also, no batter will ever have an average of 0.001. His ass would quite simply be sent back down to the minors well before that point!

Also, no batter will ever have an average of 0.001. His ass would quite simply be sent back down to the minors well before that point!

- Tue Apr 10, 2012 6:37 pm UTC
- Forum: Mathematics
- Topic: Finding points on a perimeter
- Replies:
**13** - Views:
**2348**

### Re: Finding points on a perimeter

Regarding Convex hulls: The convex hull is just that: convex. As such, you won't be able to achieve the hourglass shape you're looking for, since that's non-convex. To get the exterior points of a non-convex hull, there are other tricks you can play, such as "lifting" the point pattern int...

- Mon Apr 09, 2012 3:11 pm UTC
- Forum: Mathematics
- Topic: Math Books
- Replies:
**379** - Views:
**283379**

### Re: Math Books

Does anyone have any experience with the Stein and Shakarchi series in Analysis? I'm seriously contemplating ordering the series from Princeton University Press. They have four books, Real Analysis, Complex Analysis, Fourier Analysis, and Functional Analysis. I'm probably at early graduate-level abi...

- Mon Apr 09, 2012 1:41 pm UTC
- Forum: Science
- Topic: Why do airplanes need wings?
- Replies:
**66** - Views:
**12961**

### Re: Why do airplanes need wings?

Another method is called 'boundary layer control', which I really know nothing about, other than it is supposed to lower the stall speed of a wing by a certain percentage. However, as it generally uses bleed air from the aircraft engines, it has not proven to be highly reliable, at least, the U.S. ...

- Mon Apr 09, 2012 1:52 am UTC
- Forum: School
- Topic: Citations and Book Resources
- Replies:
**16** - Views:
**5648**

### Re: Citations and Book Resources

Since Wikipedia is unciteable in most everyday applications (unless you're writing a paper specifically *about* Wikipedia, perhaps), I'd definitely caution against it. However, many elementary topics, such as those covered in HS courses, aren't even going to be found in advanced literature. Let's sa...

- Sat Apr 07, 2012 2:17 am UTC
- Forum: Mathematics
- Topic: Ring Theory: Ideals [Homework]
- Replies:
**2** - Views:
**927**

### Re: Ring Theory: Ideals [Homework]

This is what I've come up with so far: [easy statements showing that I n J is a subring] Let r in R, x in I n J. Then, rx in I, since I is an ideal, and rx in J, since J is an ideal. Since rx is in I and J, then rx in I n J. Let r = a + b, a in I, b in J, and let x in I n J. Then, rx = ax+bx = ax+xb...

- Sat Apr 07, 2012 1:46 am UTC
- Forum: Mathematics
- Topic: Ring Theory: Ideals [Homework]
- Replies:
**2** - Views:
**927**

### Ring Theory: Ideals [Homework]

This is the final part of a multi-part problem. I and J are ideals in a ring R. We define I+J = {a+b | a in I, b in J} and IJ = {a_1 b_1 + a_2 b_2 + ... + a_n b_n | a_i in I, b_i in J}. These are ideals (proven in earlier parts of the problem). Furthermore, it can be shown that IJ \subseteq I \cap J...

- Fri Apr 06, 2012 2:49 pm UTC
- Forum: School
- Topic: Citations and Book Resources
- Replies:
**16** - Views:
**5648**

### Re: Citations and Book Resources

How do people feel about citing papers on ArXiv? I've definitely seen papers published in journals cite papers on ArXiv, but they're not strictly peer reviewed, so that makes them kinda iffy. The fact that wikipedia isn't typically a citeable source (it bothered me greatly that one of my professors...

- Fri Apr 06, 2012 2:44 pm UTC
- Forum: School
- Topic: Am i the only one that thinks the ACT is crap? <.<
- Replies:
**27** - Views:
**9560**

### Re: Am i the only one that thinks the ACT is crap? <.<

The ACT tests your ability to sit in a chair for some 3 hours or so and do a bunch of mildly mentally challenging tasks that seemingly have no purpose and bear no interest to you nor any resemblance to things you'll need in the remainder of your post-educational life, all of which bore you to tears....

- Thu Apr 05, 2012 7:01 pm UTC
- Forum: Science
- Topic: Why do airplanes need wings?
- Replies:
**66** - Views:
**12961**

### Re: Why do airplanes need wings?

First... I am not a aeronautical engineer or a physicist. However, the things to take into consideration. How important are wings. Well lets look at the purpose of an aircraft. It's to get to a destination quickly, regardless the surface below (Land or sea) and SAFELY! Now when LANDING an aircraft ...

- Thu Apr 05, 2012 6:55 pm UTC
- Forum: Mathematics
- Topic: chi² and wolfram alpha
- Replies:
**9** - Views:
**3589**

### Re: chi² and wolfram alpha

Mathematica says it's 4.3e-40 Just to add on this, I would be careful to cite such a number (obviously it's unnecessary to do so) because unless you have detailed knowledge of the specific algorithm used to compute the value, you cannot say for certain that the algorithm properly handles underflow....

- Thu Apr 05, 2012 6:04 pm UTC
- Forum: General
- Topic: Hype your ripe snipes 'n' gripes
- Replies:
**28619** - Views:
**3588228**

### Re: Pant Thread (because we need more panting)

Take the tap from the keg when no one's looking.

- Wed Apr 04, 2012 1:25 pm UTC
- Forum: General
- Topic: Hype your ripe snipes 'n' gripes
- Replies:
**28619** - Views:
**3588228**

### Re: Pant Thread (because we need more panting)

When the political phone calls start out saying "It's me again, I know we've been calling a lot but we just wanted to remind you..." Why don't you take your own hint and stop fucking calling. This makes me so glad I don't have a landline. They call my cell, which they're actually allowed ...

- Mon Apr 02, 2012 11:31 pm UTC
- Forum: General
- Topic: Men's Fashion
- Replies:
**396** - Views:
**137585**

### Re: Men's Fashion

So, does this also mean that I shouldn't invite any bankers to my wedding?

- Mon Apr 02, 2012 11:22 pm UTC
- Forum: Mathematics
- Topic: Mean of infinite sets
- Replies:
**10** - Views:
**2694**

### Re: Mean of infinite sets

Your distribution F does not necessarily need to be uniform even if the input parameters are uniform. In this sense, you can think of F as a random multivariate process. Typically, if F is nonlinear, you shan't expect a uniform distribution in your output for a uniform distribution on your input. In...

- Mon Apr 02, 2012 6:53 pm UTC
- Forum: General
- Topic: Men's Fashion
- Replies:
**396** - Views:
**137585**

### Re: Men's Fashion

Is that even a thing? You can't wear pinstripes to a wedding?

So... If someone shows up at my wedding with a pinstripe suit, what's the most appropriate judgmental response for such an apparently brazen action?

So... If someone shows up at my wedding with a pinstripe suit, what's the most appropriate judgmental response for such an apparently brazen action?

- Mon Apr 02, 2012 2:16 pm UTC
- Forum: Mathematics
- Topic: Improper integral question
- Replies:
**14** - Views:
**4022**

### Re: Improper integral question

\int \frac{f'(x)}{f(x)} dx = \ln f(x) Sorry, you lose a point. The correct answer is \int \frac{f'(x)}{f(x)} dx = \ln f(x) + C Ah shit. Thanks. No one else was using 'c's so I forgot to add it. EDIT: "c = 0" is a valid answer though,...

- Mon Apr 02, 2012 2:14 pm UTC
- Forum: Mathematics
- Topic: Mean (or Lack Thereof) of the Cauchy Distribution
- Replies:
**7** - Views:
**2593**

### Re: Mean (or Lack Thereof) of the Cauchy Distribution

In fact, in much of probability theory, Riemann-Stieltjes integration is used, which is a generalization of Riemann integration.

- Sat Mar 31, 2012 8:08 pm UTC
- Forum: Mathematics
- Topic: Program to Plot a function given a file of x,y pairs
- Replies:
**8** - Views:
**1841**

### Re: Program to Plot a function given a file of x,y pairs

Kurushimi wrote:gorcee wrote:Excel?

I don't have Microsoft Office on my computer, so I can't use that.

skydrive.live.com

Free signup, you can use excel online.

Or, google docs.

- Sat Mar 31, 2012 7:31 pm UTC
- Forum: Mathematics
- Topic: Program to Plot a function given a file of x,y pairs
- Replies:
**8** - Views:
**1841**

- Sat Mar 31, 2012 6:22 pm UTC
- Forum: General
- Topic: Hype your ripe snipes 'n' gripes
- Replies:
**28619** - Views:
**3588228**

### Re: Pant Thread (because we need more panting)

Menacing Spike wrote:Maaaaybe it's the player and not flash that's the problem?

If the environment is such that Very Good Engineers can't develop something that works properly, then the environment must take some of the blame.

- Sat Mar 31, 2012 5:36 pm UTC
- Forum: General
- Topic: Hype your ripe snipes 'n' gripes
- Replies:
**28619** - Views:
**3588228**

### Re: Pant Thread (because we need more panting)

Seriously, everyone, stop using Flash. It fucking sucks. Just stop.

I love having to refresh this streaming feed every 2 minutes because your player eats shit.

I love having to refresh this streaming feed every 2 minutes because your player eats shit.

- Sat Mar 31, 2012 4:27 am UTC
- Forum: School
- Topic: Citations and Book Resources
- Replies:
**16** - Views:
**5648**

### Re: Citations and Book Resources

As an aside, it always frustrated me in high school when we had to use MLA or APA citation styles. It never made any sense to me. If I was writing a paper for my physics class, what fucking role does the Modern Library Association or American Psychological Association have to do with physics? I mean...

- Sat Mar 31, 2012 1:10 am UTC
- Forum: Mathematics
- Topic: Motivation for self-study
- Replies:
**3** - Views:
**1414**

### Re: Motivation for self-study

It depends on how frequently you use it, and it also depends on how well you understand it the first time you see it. (You can understand something without really understanding something, y'know?) Often times, for things I use infrequently, or don't remember all the details to, it just takes a quick...

- Fri Mar 30, 2012 11:29 pm UTC
- Forum: General
- Topic: 1.64 gb in 10minutes?
- Replies:
**13** - Views:
**2894**

### Re: 1.64 gb in 10minutes?

So, 6.5 mb/s is faster than 1.5 mb/s. By a factor of a little more than 4. So she should download it in about 1/4 the time that you do. In your first post you said you had 1.5 gb/s, which would be spectacular, but then later you said you had 1.5 mb/s. I'm assuming the latter is correct. That's not t...

- Fri Mar 30, 2012 8:56 pm UTC
- Forum: Mathematics
- Topic: Laplace transforms and derivatives
- Replies:
**9** - Views:
**2257**

### Re: Laplace transforms and derivatives

I was responding to your example and statement that any function that is piecewise continuous but not differentiable will not have a Laplace transform. It's still true, but we get around it with the Heaviside step function. Which is one of those "kind of a functions" with various definiti...

- Fri Mar 30, 2012 2:08 pm UTC
- Forum: Mathematics
- Topic: Laplace transforms and derivatives
- Replies:
**9** - Views:
**2257**

### Re: Laplace transforms and derivatives

abs(x-1) Wolfram Alpha gives me (e -s (e s s-e s +1))/s 2 +e -s /s 2 , which simplifies to (s-1+2e -s )/s 2 . Of the derivative? That's not what it's giving me at all. Either way, you can take the Laplace transform of this function by substitution. It occurred to me later that dabs(x-1)/dx can be r...

- Fri Mar 30, 2012 3:58 am UTC
- Forum: Mathematics
- Topic: Laplace transforms and derivatives
- Replies:
**9** - Views:
**2257**

### Re: Laplace transforms and derivatives

IIRC, The Laplace transform doesn't require differentiability, just piecewise continuity. So, any function that is piecewise continuous but not differentiable will not have a Laplace transform. True. To break applicability on that criteria, it would require that a function which is piecewise contin...

- Fri Mar 30, 2012 3:21 am UTC
- Forum: Mathematics
- Topic: Laplace transforms and derivatives
- Replies:
**9** - Views:
**2257**

### Re: Laplace transforms and derivatives

IIRC, The Laplace transform doesn't require differentiability, just piecewise continuity. So, any function that is piecewise continuous but not differentiable will not have a Laplace transform.