Recent content by pagheca

ok, thanks for all the advice! Now it works. pagheca

Hi everyone, I would like to simulate as a start the throw of two dices and want to check how many times I get a certain value from 0 to 12. I used a while loop (see attachment) but it doesn't work as it never exit the loop. N is the number of throws to try. Y[0,P is a vector, j is an index. Z...

got it: I have to specify the index, of course... I was confused by the fact it was a one element vector! Thanks again.

thanks very much, Peter. A very smart solution. However, the result is a vector itself. How to convert it to a number? Thanks again!

Hi, I'm looking for the simplest way to find the index of the element of a vector that is closer to a given value. Suppose the vector is f[i:=i^2 and the value V:40 . The solution is i=6 as 6^2=36. How to find that i value? Do there is any function doing that? Do you know any trick using the...

Thanks for the replies. Reidh: Unfortunately I haven't yet a sample of the material. I'll do extensive tests but, as I have a small budget, I want to understand better before to buy. MintJulep: right, the other material is hardened stainless steel. What I need to know is how Zirconia/steel...

Hi, does anyone know the rolling friction coefficient of any commercially available Zirconia ceramic brand. Thanks in advance for any help

Hi, I have a similar problem, and was wondering if you found a solution. In my case, the speed is very low but we need a system running for very long time and a severe constraint on max friction. Magnetic bearings and Superconducting magnetics bearings cannot be used in our case. Any pointer to...

Thanks for the reply and the advices. Some comments: 1) I can't use any magnetic field around this device as this is part of a detector very sensitive to magnetic fields. 2) If I understood dvd suggestion, what worries about grinding to a vee shape is the resulting dragging of the edges of the...

Reading my post, I understand I've probably been not clear enough... My problem can be described in this way: suppose you have to rotate a disk supporting it from the circumference (= nothing is permitted below or above the disk, except for a cm or so close to the circumference itself). What...

Hi, I have to rotate a disk weighting at about 4 kg, at 12 rev/sec, supporting it from the circunference (dia=300mm). I have to dissipate the minimum possible heat (less than a few W) and work at a temperature of ~ -200 C with dry lubrication. The rotation should keep going maintenance free for...

I found the following problems with MathCAD 11. I have to numerically integrate a function in the form F(f,k,T)=F(exp(-hf/kT)), where h, f, k and T have their own units. Most of you will have already understood I'm dealing with Planck radiation law, however... I would prefer to keep working...

Hi, How to align reference dimensions to a particular directions? I have a quite irregular assembly (so, I can't use the sketch). I need to show the envelope of the assembly (a concept design) aligned to the 3 main axis. If I use a reference dimension, it will show the direct (shortest)...

I couldn't find any information in Dr. Dobb's j. online. Expecially the first pointer in Madcow's reply has been usefull. One information I still miss is the way disks are layered (materials, thickness). I guess patents expired as the technology is quite old. Thanks very much for the...

Hi, I am looking for information about the floppy disk drive technology (yes, the old one): the way data are encoded on the disk, materials and technology disks and heads are made, friction, wearing, lifetime, signal/noise ratio at head/disk level, circuitry for directly reading the signal...