# Search results

1. ### Is it possible to see newton rings in CT (xray) images?

I have seen what looks like newtons rings interference pattern in transverse CT images of 2 solid water block on top of each other. My understanding is that newtons rings occur in visible light eg photography or scanners. Can anyone shed some light on this? :)
2. ### Calculation of peak acoustic intensity (in water)

If we know the max. pressure (p) is 2.5 MPa and T = 20 C. Peak intensity, I = p^2 / rho * c where rho = density of water: 0.9982E03 kg/m^3 and c = speed of sound in water: 1482.3 m/s at 20 C I = (2.5E06 [Pa])^2 / 1.4796E06 [kg/m^2/s] = 4.2241E06 W/m^2 Is this correct?
3. ### Bayesian stats: how to update probability?

I am trying to use Bayesian methods (Bayes rule) to predict further datapoints (at point n,n+1,n+2 etc..)... I begin by generating a normal pdf using previous 75 datapoints (prior: n-75 to n-1) with mean value, μ: 1.25 and standard deviation, δ: 3.67. Note: previous datapoints range from...
4. ### Thickness of lead required for 200 keV x-rays?

I found that factor online.It said to get intensity to < 1% but by my calculations, for 200 KeV beam using formula: HVL = 0.693/u need 7 HVL layers to get to 0.8% which is 4.48 mm. where u = 10.15 cm^-1
5. ### Thickness of lead required for 200 keV x-rays?

is this correct? mass attenuation coeff. = 8.636 cm^2/g 8.636 * (density of lead: 11.3 g/cm^3) = 975.868 per cm thickness (mm): t= 9.21 / 975.868 = 0.009 cm = 0.09 mm
6. ### Can following trigonometric equation be simplified:

yes. thanks. corrected above.
7. ### Can following trigonometric equation be simplified:

yeah. thats it. thanks.
8. ### Can following trigonometric equation be simplified:

Yes. I mean variables are arbitrary. I just want to know if the left side of the eqn can be simplified at all.
9. ### Can following trigonometric equation be simplified:

Fx = sin [ 90 - theta ] * [ dX - [tan (theta) * dY ] ] ??
10. ### Electron in magnetic field equation

equation for radius of curvature of relativistic electron in magnetic field? is this correct: R = gamma * m * v / e * B where gamma is lorentz factor, m is electron mass, v is velocity, e is electron charge and B is magnetic field strength.
11. ### What ACTUALLY causes a magnetic field to be generated when there is a current?

Here's a question for you: Why is there SOMETHING and not NOTHING? Think about it!
12. ### Box Muller transform

Can i use box muller transform to generate a distribution with two different sigma (i.e. sigma_x and sigma_y)? I want to generate a random gaussian angle (C) relative to z axis on circle plane, then set the angle relative to the x, A and y axis, B, wrt to the original angle. However, I want...
13. ### Help understanding the Del operator

del is partial differentiation operator in x/y/z. It's for 3 dimension.
14. ### How to rewrite 2D Gaussian eqn in terms of x?

yes sorry i mean solve for x let f(x,y) = y = 2. say
15. ### How to rewrite 2D Gaussian eqn in terms of x?

http://upload.wikimedia.org/math/1/9/8/1983171154842b0b061fc42aa5eb7642.png" [Broken] How to rewrite this 2D Gaussian eqn in terms of x? i need to calculate the x and y values. let x0=0 and y0=0. is it complex?