1

Geek Speak / Does Ubuntu-13.04 have a printing problem?

« on: 16/05/2013 19:04:45 »

Is anyone using Ubuntu-13.04 ? , I tried it but found a strange problem printing it finds a driver for my HP LaserJet 4M plus and allows me to send text to the printer but blank pages come out !

2

Technology / Re: Why switch to digital radio?

« on: 15/05/2013 15:35:20 »

The PAL system produced rather poor results when it was first introduced in 1964 but by 2010 when digital processing of the decoding had taken over the results were almost indistinguishable from 720p which surprised me when I purchased a modern TV. I would add I have a clear view of a transmitter 10 miles away so noise or multi path is not problem a problem.
TV has been compressed since the start in the UK in 1936 by means of interlacing which I always considered a mistake as most domestic receivers paired lines to some extent reducing the vertical resolution to less than 190 lines.

3

Chemistry / Re: Can pH for any compounds be calculated with an equation?

« on: 15/05/2013 12:23:29 »

With the aid of super computers it is possible to compute the mass of particles such as Protons from first principles so I would have thought it would be possible to compute the ph value of compounds although I cannot see any good reason for doing it.

4

Technology / Google glass

« on: 15/05/2013 07:32:31 »

I understand Google glass wearable computer communicates via Wi-Fi and Bluetooth will this lead to another brain tumour scare do to its proximity to the brain ?.

5

Physics, Astronomy & Cosmology / Re: Can gamma rays push objects?

« on: 13/05/2013 18:04:25 »

So its the total energy of the beam that is relevant not the energy of individual photons, whenever this matter is mentioned the actual frequency of the radiation is always quoted but it could just as well be from the 198kHz Droitwich radio station as from a gamma ray source if the power was the same.

6

Physics, Astronomy & Cosmology / Re: Can gamma rays push objects?

« on: 12/05/2013 14:27:33 »

I understand a 300MW beam of visible light will produce a thrust of one N , will the same radiated power in gamma rays produce the same thrust as I would expect the greater momentum of the gamma ray photons to be modified by their reduced number. 

7

Geek Speak / Re: Windows blue 9364

« on: 12/05/2013 04:42:41 »

There seems little interest in windows blue but I will report progress, The x64 versions is now available as windows 8.1 as well as the x86 version as windows blue.
It still contains the warning that you darest not use it but fixes are available to hide this !, it incorporates a new version of the browser e.g. IE11 that is at present not compatible with banking although there is a compatibility mode and also many useful programs will not run because they require NET3.5 that will not run, and many of the fixes that enable criminals to run extended life versions of trial programs also do not run so I am told but of course I have not tried them ! .
It runs fast and loads fast and generally looks like the regular windows 8.
The programs that get rid of the Disney land stuff and make it look like windows 7 work OK

8

Chemistry / Re: How could I create a small steam explosion?

« on: 06/05/2013 16:50:05 »

A balloon inflated with acetylene makes a nice big sooty bang.

9

Physics, Astronomy & Cosmology / Re: What physics and maths topics do people find hardest to grasp?

« on: 06/05/2013 08:09:34 »

What I find difficult about maths is what do all the strange symbols represent I understand about half of them and have recently learnt about Bras and Kets but am always quite defeated by matrix's.
Arithmetic is no problem having grown up with the strange imperial units and £.S.D  money which hones ones skills.

10

Chemistry / Re: Can we make more helium?

« on: 05/05/2013 11:27:24 »

How about water vapour at 110°C would it be any better than air at the same temperature although it might be rather difficult to work with except perhaps in a Zeppelin

11

Chemistry / Re: Can we make more helium?

« on: 05/05/2013 09:11:14 »

How does Nitrogen rate for buoyancy ? I understand that the gas sold to inflate balloons is normally diluted the Nitrogen to reduce the cost while maintaining adequate buoyancy.
I notice that Argon is cheaper than Helium is it any good for lifting ?

12

Physics, Astronomy & Cosmology / Are individual gravitons detectable?

« on: 05/05/2013 08:33:50 »

This is a quote from the Scientific American article
The Search for a Unified Theory: A Pipe Dream? 

"The fundamental problem with detecting gravitons is the extremely weak nature of the gravitational force. To address this problem researchers have designed exceedingly sensitive equipment that should in principle be able to detect even discrete gravitons."

This is a ludicrous claim as the exceedingly sensitive equipment has not as yet detected the gravity waves from colliding black holes and Gravitons are postulated to be something like 10^-10 the mass of Neutrinos


[MOD EDIT - PLEASE FORMAT YOUR THREAD TITLES AS QUESTIONS, IN LINE WITH THE FORUM CONVENTION. THANKS.]

13

Physics, Astronomy & Cosmology / Re: How massive would an asteroidneed to be for gravity to make it spherical?

« on: 01/05/2013 13:30:09 »

Off the top of my head I would have one with the mass of Ceres an opinion supported by Wiki but of course it depends to some extent as to by what materiel it is composed.
The most spherical objects are or course neutron stars which are much smaller than Ceres but have a mass of at least 3*10^30 kg

"The asteroid Ceres appears to be the smallest spherical asteroid, with a mass of around 10^21 kg"

14

Physics, Astronomy & Cosmology / Re: How long do you have to accellerate at G to reach the speed of light?

« on: 01/05/2013 13:16:29 »

There are many unfortunate consequences of travelling near the speed of light, microscopic specks of dust would be like express trains when you hit them and the CMBR would be blue shifted up to Gamma rays.

15

Technology / Re: How do you describe a Transformer?

« on: 29/04/2013 19:18:29 »

The fun begins when you have three phases

16

Physics, Astronomy & Cosmology / Re: Discuss: Did I see 3 Rainbows?

« on: 28/04/2013 18:52:10 »

Triple rainbows do exist in theory but generally they are too dim to see without image enhancement

17

Technology / Re: Transformer

« on: 28/04/2013 18:42:35 »

As a boy at school I was fascinated by transforms and learnt a lot about them by trial and error, one important point is that you must not over saturate the core with the laminations that were available at the time a good rule of thumb was that the turns per volt at 50Hz should be one turn per volt for a core area of 9 square inches and proportionally more turns for a smaller core area i.e your 500 turn winding should have a core area of 3.96 square inches if you are to apply 220V and you should not exceed 132V on the 300 turn winding 

18

Physics, Astronomy & Cosmology / Re: If Gravitons exist they must escape a black hole's EH to convey its gravity

« on: 27/04/2013 19:35:11 »

Why is it required that the matter beyond the event horizon be compressed to a quasi infinite extent would the event horizon not still be there if the density was say three times that of a neutron star.

19

Physics, Astronomy & Cosmology / Re: How would a parallel universe affect our Universe?

« on: 27/04/2013 15:28:27 »

I seem to have expressed myself rather badly I was trying to say that you can never pass out of the universe because as you say there is no "outside" hence nothing outside can be influencing us, I can almost understand those that invoke the idea of a god as some of these ideas are difficult to comprehend.

20

Physics, Astronomy & Cosmology / Re: Liquid metal core of the Earth, is cooling?

« on: 27/04/2013 10:53:28 »

There are various opinions as to the Earths centre temperature

http://phys.org/news/2013-04-earth-center-degrees-hotter-previously.html#ajTabs

21

Geek Speak / Re: How do I disable multi-operating system choice screen at start-up?

« on: 27/04/2013 06:22:43 »

Dual boot Pro can be a great help sorting screwed up boot loaders but it takes no interest in non Windows boots.

22

Physics, Astronomy & Cosmology / Re: How would a parallel universe affect our Universe?

« on: 26/04/2013 20:59:08 »

I have read somewhere that asymmetries in the CMBR might be due to adjacent "universe's" but I am far from convinced.
I think our universe is surrounded by an impenetrable barrier much like a BH.

23

Technology / Re: Resonance

« on: 26/04/2013 09:26:28 »

Electric motors commonly achieve efficiencies of 90% it is futile to add weighty gadgets to try and produce greater efficiency a resonant device would only capture energy over a narrow range of bump spacing's you need a more broadband arrangement.
An electrical shock absorber will tend to capture energy more at high frequencies you need a hydraulic arrangement that is inherently broadband compressing gas into a reservoir or charging a battery or spinning a flywheel  , there has been much research done in this area for use on F1 cars presumably some has been published. 

24

Technology / Re: Resonance

« on: 25/04/2013 08:04:23 »

I am a little puzzled just what you are trying to do you talk of a vibrating spring electrically actuated, if you have a supply of electrical power the best way to use it for propulsion is with a conventional electrical motor.
if you are trying to recover energy from the spring set vibrating by the bumps over which the vehicle travels then see CliffordK's link   

25

Technology / Re: Can you still get bread sliced to order?

« on: 24/04/2013 21:02:52 »

My local Morrison store had some special offer toast thickness loaves for £0.50 ($0.75) today who needs slicing machines ?