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25.05.2010, 14:49
| | Re: Ask a Scientist | Quote: | |  | | | A detector next to me shows cosmic rays a handfull of times per day, considering it's only scanning for about a minute <50 times a day.
I also have used quite a few pcs in my history with a near zero crash history, so in my experience, computers are fairly safe-if the bits get flipped as often as reported, the modern pc must have a fairly decent error detect and fix method. | | | | | Managed to find some more recent figures (2004), from a paper by Mastipuram & Wee, of Cypress Semiconductor:
A cell phone with one 4-Mbit, low-power memory with an SER (Soft Error Rate) of 1000 FITs per megabit will likely have a soft error every 28 years.
A high-end router with 10 Gbits of SRAM and an SER of 600 FITs per megabit can experience an error every 170 hours.
For a router farm that uses 100 Gbits of memory, a potential networking error interrupting its proper operation could occur every 17 hours.
A laptop with 256 Mbytes (2 Gbits) of memory, on an airplane over the Atlantic at 35,000 ft has a SER of 600 FITs per megabit, or 100,000 FITs per megabit, resulting in a potential error every five hours.
...
Neutrons are particularly troublesome, because they can penetrate most manmade construction; for example, a neutron can pass through five feet of concrete. The flux rate is geoposition-dependent and increases at higher altitudes due to a lower shielding effect of the atmosphere.
In London, the effect is 1.2 times worse than at the equator.
In Denver, with its high altitude, the effect is three times worse than at sea level in San Francisco.
In an airplane, the effect can be 100 to 800 times worse than on the ground. | 
03.06.2010, 19:32
|  | Forum Veteran | | Join Date: Jan 2007 Location: Zurich
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| | Re: Ask a Scientist
Another question... a couple of years ago I was watching the German Galileo how-things-are-made TV program. This episode was all about how they make sticking plasters. Everything in the manufacturing process was as expected, except that they mixed chilli powder in the dressing mix. Why do they do that?
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03.06.2010, 19:59
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| | Re: Ask a Scientist | Quote: | |  | | | Another question... a couple of years ago I was watching the German Galileo how-things-are-made TV program. This episode was all about how they make sticking plasters. Everything in the manufacturing process was as expected, except that they mixed chilli powder in the dressing mix. Why do they do that? | | | | | I seem to remember something about chili powder speeding up the rate of coagulation on application to open wounds.
I think that it is usually used as a tincture in this particular application. | 
04.06.2010, 17:40
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| | Re: Ask a Scientist
Just got a probability problem,
If you randomly pick 200 figures from 1-700, what is the chance of having 5 figures in a row? | 
04.06.2010, 17:56
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| | Re: Ask a Scientist | Quote: | |  | | | Just got a probability problem,
If you randomly pick 200 figures from 1-700, what is the chance of having 5 figures in a row? | | | | | How do you know there is a probability of getting 5 figures in a row?
| 
04.06.2010, 18:03
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| | Re: Ask a Scientist | Quote: | |  | | | Just got a probability problem,
If you randomly pick 200 figures from 1-700, what is the chance of having 5 figures in a row? | | | | | I don't do homework.
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04.06.2010, 18:09
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| | Re: Ask a Scientist | Quote: | |  | | | How do you know there is a probability of getting 5 figures in a row? | | | | | Theres always a probability of something
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04.06.2010, 18:13
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| | Re: Ask a Scientist | Quote: | |  | | | | Quote: | |  | | | Just got a probability problem,
If you randomly pick 200 figures from 1-700, what is the chance of having 5 figures in a row? | | | | | I don't do other people's homework. | | | | | Fixed that for you  | 
04.06.2010, 18:26
|  | Moddy Wellies | | Join Date: Apr 2007 Location: North Yorkshire
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| | Re: Ask a Scientist | Quote: | |  | | | Just got a probability problem,
If you randomly pick 200 figures from 1-700, what is the chance of having 5 figures in a row? | | | | | I’m no maths expert but here’s my guess.
Let’s take 1-5 as an example;
There’s a 1/700/5/200 of getting first number in range = 1/0.7
+ 1/699/4/199 = 1/0.878
+ 1/698/3/198 = 1/1.175
+ 1/697/2/197 = 1/1.769
+ 1/696/196 = 1/3.551
= 1/8.073 - Which means you will get one specific range 1/8 of the time.
There are 696 possible ranges, so i reckon that you will get, on average, 86 occurrences of 5 numbers in a row each time you pick your 200 numbers.
This may be complete rubbish of course. If it is then I’d be interested to know where I went wrong. E.T.A. - To answer your actual question. You are guaranteed a run of 5 100% of the time. There aren't enough numbers to allow a maximum of 4 in a row. I think you'd need to pick less than 140 numbers to give you any chance.
__________________ Nothing of value kept in this post overnight. | 
04.06.2010, 18:30
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| | Re: Ask a Scientist | Quote: | |  | | | How do you know there is a probability of getting 5 figures in a row? | | | | | Because Jimmy Bee says so: | Quote: | |  | | | Theres always a probability of something | | | | | | 
04.06.2010, 19:15
| Newbie 1st class | | Join Date: Dec 2009 Location: Basel
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| | Re: Ask a Scientist
Great idea and nice thread!!!
I think it will keep you going for many hours  !!!
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04.06.2010, 19:32
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| | Re: Ask a Scientist | Quote: | |  | | | I’m no maths expert but here’s my guess. | | | | | To me, the OP didn't state the problem clearly.
Are any of the 200 numbers chosen repeatable?
This makes a huge difference in the problem and the resulting stats.
What is meant, exactly, by five figures in a row? The same five figures? Five figures in ordinal sequence (e.g. 3,4,5,6,7)?
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05.06.2010, 11:09
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| | Re: Ask a Scientist
well I had this explained to me y'day evening, out there on a lovely terrasse by the lake, sounded as easy as the fresh beer running down my throat then ... but there's just no way I could repeat the solution just now, sorry!! | 
07.06.2010, 22:25
| Member | | Join Date: Aug 2009 Location: Oberlunkhofen
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| | Re: Ask a Scientist
Question to any gear heads:
Ive been reading gear formulas for a few days, and cant figure out how to relate module, or pitch diameter to any physical dimension of the gear. I have a technical drawing of a gear with 18 teeth. it says module 2 and pitch diameter 36.6. That doesnt agree with the formulas, so which can I determine correct by another means?
If two gears are mating properly such that their pitch diameters are tangent, then they are pulled slightly apart (but still meshing) are the pitch diameters still the same?
thanks
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07.06.2010, 23:01
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| | Re: Ask a Scientist | Quote: | |  | | | Theres always a probability of something | | | | | Well, if you include zero probabilities, e.g. breaking physical laws or logic.
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18.06.2010, 00:26
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| | Re: Ask a Scientist
I bought a led shower head, the kids got excited and are having fun with it. The question: there is no battery required...where does the energy come from?
led shower head? | 
18.06.2010, 00:50
|  | Forum Legend | | Join Date: Aug 2008 Location: Zürich
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| | Re: Ask a Scientist | Quote: | |  | | | I bought a led shower head, the kids got excited and are having fun with it. The question: there is no battery required...where does the energy come from?
led shower head? | | | | | A small water turbine in the shower head?
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18.06.2010, 01:09
| | Re: Ask a Scientist
In fact the hose leading up to the shower head is a deuterium conduit, the shower head itself contains a taurus microsun fusion reactor, the water exiting is the fusion product, and the light is from selectively thinned steel letting through the artificial sunlight.
Science eh.
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18.06.2010, 02:53
|  | Moddy Wellies | | Join Date: Apr 2007 Location: North Yorkshire
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| | Re: Ask a Scientist | Quote: | |  | | | In fact the hose leading up to the shower head is a deuterium conduit, the shower head itself contains a taurus microsun fusion reactor, the water exiting is the fusion product, and the light is from selectively thinned steel letting through the artificial sunlight.
Science eh. | | | | | Ah, that might explain why mine stopped working.
I'm a taurus and I have some sort of reactor for the sun shining out of my arse. The two clearly caused a mini wormhole which swallowed my shower head's shiny bits.
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18.06.2010, 06:09
| | Re: Ask a Scientist | Quote: | |  | | | I bought a led shower head, the kids got excited and are having fun with it. The question: there is no battery required...where does the energy come from? | | | | | The one I saw had "hydro-electric" written on the box. Could be a clue.
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