Beam Definition and 1000 Threads

Basically, I don't understand how they got x=L/2 and x=r paths of T_in and T_out. Below is elaboration. I don't understand the choice of paths for incoming and outgoing photons in the solution for c). The solution put incoming path to x=L―/2, while outgoing x=r. As I interpret it, Tin is the...

From what distance does the diffuse radiation of a „hair removal laser“ cease to be a threat? I apologize for the peculiar question, but I'm curious about the following matter: I walked past the window of a hair removal studio about 50 meters away earlier, and I noticed repeated bright red...

TL;DR Summary: I have a cantilever beam with fixed end, known rectangular cross section and total length h. A uniform load is applied on the beam from a distance L from the fixed end, to the free end. The E modulus and inertia I are known, and they are two different constant values for 0<x<L...

Hi, I'd like to calculate the maximum deflection of a simply supported beam with spring support in the middle and UDL (uniformly distributed load) acting on the whole beam: Here's my derivation, starting from the known formula for maximum deflection of a simply supported beam with UDL and no...

I think that there might be several solutions. I drawed one possible situation: I think that this is just geometry, but I don't know how to solve it simply. I had an idea that if the beam was going through the black axis, then it would be easy to calculate, and that would be aslo solution for...

Let me start this off with saying I am just a uneducated idiot, But after reading about Zap Energies sheared flow pinch reactor I was wondering if you could use a similar concept in a neutral beam injector? Like could you first compress and heat the plasma inside of a NBI using a pinch, then...

Hi, I am working with leaf springs and studying the derivation of the formula for the deflection of such a structure. The derivation is shown here: My only doubt is how to obtain the following formula: $$\delta=\frac{L^{2}}{8R}$$ where: ##\delta## - deflection, ##L## - length of the beam...

I've look if there was any way to get the "image size" or a ratio to use the Mirror Equation to find the focal length, but nothing. I think it's base on some geometry, but I don't see the relation.

I'm building an aluminum tandem axle (7k total capacity) trailer. Boat (18'/1300#) on the rear and a Ryker Can Am 3 wheel (750#) on the front. It's a 23'-6" x 6'-8" bed. Max live load will be approx 2250#. 900# frame weight. 230# axles. I'm testing beam sizes with online calculators and need...

Hello all, I'm trying to understand the maximum moment on a free beam. Consider a tail sitter drone that is simplified into being a beam with two motors fitted with propellers on the end of the beam (see the photo below), let the payload be estimated as two, 2 newton loads going downwards. If...

Hello All, I'm trying to figure out how to strengthen a box beam that's been welded to another box beam. In the photo on the left is 2 beams welded to each other, they are 2x1" Aluminum 6061-T6, with a 1/8" wall thickness. The yellow lines indicate the location of the weld. A force of 216 lbs is...

Hello, The Mach-Zehnder interferometer makes it possible to highlight the corpuscular and undulatory aspect of light, (in particular using single photons). By using the "continuous" beam from a coherent source, one is able to visualize directly on two screens E1 and E2, an interference pattern...

Hi. I am studying the wavefront evolution of light from a star. In the papers I have read, the star is often treated as a point source and the light is approximated as a line (geodesics), but this approximation is not very useful when I study the wavefront evolution, so I want to extend the...

Here is the diagram of the cs: As a premise I must say that this topic(shear center and shear flow distributions) is still very hectic in my mind; I aim to clarify it a bit by asking you guys this :) So, in order to identify the SC location, I must compute at what distance a point shear force...

Attempted creating equations for zeros of torque and components of forces in x and y as seen in picture. Got lost with having only variables and the d & 2L for the length of the beam. Not sure how to do the question with two points of contact between the beam and the sign. Is the center center...

I'm wondering what happens when fast electrons (100 - 300 keV) interact with a beam (diameter 1 to 10 μm) of slower electrons (1 to 10 keV), which is at right angles to the trajectories of the fast electrons. The beam of slower electrons is relatively dense with 1 to 10 electrons per μm line...

Hi all, Why was the thickness of the beam considered when moment was being calculated and why was the horizontal component of the 600 N force used in calculating the moment? That part is unclear to me. Please explain it. Am I looking for the logic behind using the horizontal comp. and the...

Figure: My attempt at a solution: We know that ##Q=A_T## We calculate ##Q##: $$Q=\dfrac{3\cdot 480}{2}+\dfrac{600\cdot 6}{2}+600\cdot 2=3720\, \textrm{lb}$$ Then we look for the point ##\overline{x}## of the centre of gravity: $$\overline{x_1}=1\, \textrm{ft},\quad...

Hi, good evening/morning/night! I have a problem with this 2 homework problems about curved beams. In both I must calculate the stress at points A and B. My procedure is correct, but for some reason in: First problem - the effort in A is very close to that of the teacher, but the effort in B...

Hello! I am trying to align a bow-tie cavity and I noticed a behavior of the beam spot that I can't explain with my (limited) knowledge of cavities. For reference, I am scanning the current of the laser in order for the laser to follow the cavity. I attached below 3 frames from a video I took of...

Is there a math that describes these shapes at least one frequency?

1) really does not make sense to me. It is not clear to me how light could be reflected in multiple directions if the source is not a tilted mirror or another object with specific properties. I think the thought of the "point" P confuses me. Further, the fact that light travels in the opposite...

A Ion source is a device that allows creating ion beams (e.g. argon ions) and to project them outside the device, for example to be further processed by a particle accelerator, or to irradiate materials or biological tissues etc. Now, suppose the ion beam is coupled with an EM wave, especially...

I know that for any coliders beams are not exactly the same size but they can be approximated to the same value as the deviation is relatively small, such as LHC. My questions: 1- are there currently working or planned colliders with unequal beam sizes? 2- for coliders of different particles...

Each weight: 2 Kg Hello All, I'm trying to understand an "apparent weight" problem and check my answer. Please use the picture attached. A weightless beam is at first resting over my palm, it has one 2 kg weight on each end of it. It is suspended to the ceiling by a rubber band. I drop it and...

Does electron beam in empty space generate magnetic fields around them just as with current in conductor. If yes, then is it experimentally proven that two parallel electron beam would attract each other.

So.. question: - How do I know that only the pin is at work at E and not those 2 beams? my guess: It is because those 2 beams are connected to the pin whilst the pin is the one that exerts a force on that walking beam DEF?

In an I-beam, the shear flow is usually shown drawn as on the left, not as drawn on the right. I do not understand why. I do understand: The total horizontal shear force must be zero, consistent with statics.This is satisfied in both images. The vertical direction matches the direction of the...

Hi, I am interested in simulation of parallel beams for neutrons and photons (separately of course). Any ideas on how to simulate them in MCNP5 or MCNPX?

Hello! I see that in experiments at facilities like ISOLDE, they produce molecular beams at energies of tens of keV. If I understand it right, they first create the molecule as a positive ion, and using electric fields (and maybe magnetic for mass selection) they take the particle out of the...

Hello! I have to calculate the deflection of a beam at at given point (C). The books says the should be a moment which plays a role in this deflection. How does this moment occur? I have drawn a FBD but couldn't find a moment? Should I divided the beam into separate parts or so? What am I...

A red laser with the diameter of 3mm is directed towards a piece of glass. It has the effect, P of 1mW. The angle of incidence is 90 degrees. The glass has refraction index n2= 1,5 and thickness 2 cm. Its front side is convex with a convergence radius,R, of 11 cm. The back side is plane. Whats...

Summary:: If you send a laser beam through a prism, can you measure any shift in wavelength at the other side of it? This sounds like a high school experiment and the concept is simple. I feel the laser should emerge monochromatic and at the same wavelength it went in. Do you get this result...

I have a problem where I have a metal tube that I am modeling as a cantilever beam which is fixed at one end and has a point load at the other end. The material of this beam is 304 stainless steel, the inner diameter is 0.5mm, the outer diameter is 2mm, and the length of the beam is 4.15mm. With...

Hello! Someone mentioned to me about about a way to produce in flight neutralization of atomic/molecular beams by making the beam pass through a gas of particles produce through ablation (and not use a neutralization cell as it is often done). From my understanding, basically, one has a region...

I haven't been able to pinpoint a definition of "angular divergence" of a laser so by pure intuition I assumed it would be something like ##\theta=\frac{2R}{D}## and with that I have that the radius of the lase beam is ##R=\frac{D\theta}{2}=90\cdot 5 \cdot 10^{-6} m=450\ \mu m## so...

Hello, I would like to discuss with my students the deflection of electrons in electric and magnetic fields. For this purpose, I would like to perform the experiments with electron beam deflection tubes and teltron tubes. How would you implement this organizationally in the classroom? There are...

Hello, there. Suppose a Gaussian beam is sent and is received at a great large distance, i.e., the propagation distance ##z \gg z_R## the Rayleigh distance. The Gaussian beam can be described by $$E_0 \frac {1}{w(z)} \exp \left ( \frac {-r^2}{w(z)^2}\right )\exp\left ( -i\left (kz+k\frac...

If one Googles for "laminar flow nozzle", one finds many interesting tutorials on creating a nozzle for a laminar water jet; a stream of water that remains coherent over a long distance without breaking up. These typically consist of a large-diameter tube with regions inside (like sponges and...

Hi, I'm trying to calculate the deflection of a leaf spring. I've found several formulas but the one I'm currently using looks like this: $$f=k \frac{F L^{3}}{6EI}$$ where: ##k## - coefficient depending on the way leaves change their shape in the width direction (in my case it's ##1## because...

I tried using the equations above, but I wasn't really able to come up with an intuitive explanation. From my understanding, the electric field vector only varies in the x-y plane while the magnetic field vector only varies in the z-y plane. Also, both vary sinusoidally and both reach extrema...

So I am trying to understand how to estimate the amount of deflection [D] the vertical beam shown above would experience if the base it is attached to is accelerating at a constant acceleration [a] of 9.81 m/s. I assume the Force [F] would be equal to weight of the vertical beam (mass x...

I am trying to design an acrylic light pipe that has a 3W power red LED input with 60 degree beam angle. I need a reasonably collimated exit light beam or at least a narrow angle output. What I'd like to know is - what is the optimum shape of the exit end of the light pipe to produce the...

a) My idea is: 1. Find the energy created by annihilation process, which is ##E=2mc^2## where m is the mass of electron 2. Find the wavelength of photon by using formula E = hf 3. Find the speed of positron by using the formula of de broglie wavelength 4. Find the p.d by using conservation of...

Hi all, Currently I am working on a home-project, making a trike. Now just for fun and because I like to calculate things, I calculated the deflection of a frame with a load. The frame is shown in the picture below, I added the force for clarity. With my analytical calculation I found a...

Hi guys, I'm wasting much time on this problem but still can't manage to get to a solution; I'll attach my attempt below. I started with drawing the FBD of the beam "sectioned" at point C, in order to find an expression for the internal shear force at that point and then equal that to zero...

Hello! I am trying to measure the gaussian profile of a laser beam, which is supposed to be T00. The profile shown in the specifications looks very Gaussian, and the laser is brand new. I am using this camera and I am using 2 of these wedges to guide the laser beam into the camera (mainly to...

Hello! in this good afternoon ;). I need some help for this beam and his support reactions. The problem it is done, but my result its different from the teacher`s result. I'm sure my answer is correct, as even the "SkyCivbeam" online software also gives the same results. it appears that the...