Lead Definition and 282 Threads

Hi, I'm trying to simulate how much lead i need to put in front of my source to reduce low energy scatter from reaching my detector. I have 4 cells currently. Cell 1: The source cell, im using a Cs137 source (0.662 MeV). Cell 2: The collimator. I'm simulating a cylinder to be placed in the...

Hello, I'm currently trying to compare theoretical results with an MCNP simulation. I'm using two discrete sets of data, intensity (probability) and linear attenuation coefficient, both functions of energy, to produce an attenuated energy spectrum after x-rays have passed through a thin layer...

The double lead guitar technique was invented by George Harrison on Your Bird Can Sing but the style didn't catch on. Jimmy Page put it on the map in Ramble On, then the Allman Brothers made it their signature. I like double lead guitar because that unique soaring sound is something no other...

I want to use crystals from China for baby jewelry and it turns out that they use lead for the crystals - is there a risk of exposure through the skin to these crystals for babies

Margaret Hamilton the Pioneering Software Engineer Who Saved the Moon Landing https://interestingengineering.com/margaret-hamilton-software-engineer-who-saved-the-moon-landing Margaret Hamilton began working with Edward Lorenz, the father of Chaos Theory, in MIT's meteorology department. As...

So I am a fan of astronomy, cosmology and astrophysics from a FAR. The math is way beyond my abilities but I like to just sometimes read and think about the very small parts I am able to comprehend. So my hats off to all of you that are able to fully enjoy this stuff, you're very lucky...

:)

Summary:: Calculate the torque needed to move a load with a lead screw. Torque is needed in order to find the right DC motor and coupling. Hello, I have a design with using a lead screw to move a load (see sketch below). The load will operate in both directions, in order to select the right...

https://www.caltech.edu/about/news/contrary-to-previous-belief-strike-slip-faults-can-generate-large-tsunamis

This is again based on what was said by the Director of AIIMS in a press conference. He said that many people are self-medicating, and taking high dose of steroids even in mild COVID infection, which increases viral multiplication and leads to viral pneumonia. From this new article, Two...

I was thinking about ballistic pendulums and the symmetry they exhibit. In the simplest case, you have one ball that begins at a certain height and collides with another ball at rest. You can calculate via conservation of momentum and energy the new velocities and max vertical displacements...

Attempt : I begin by plotting the graph of depth x against mass of pellets m as shown alongside. Using ##m_B = \Delta m_L\Rightarrow m_B = \rho_L A_B\, x(B)## where ##\rho_L## is the density of the liquid, ##A_B## is the cross-sectional area of the boat and ##x(B)## is the depth to which the...

Hi everyone! I'm a mechanical engineering undergraduate and am designing a linear motion system for a school project. I hope to be able to use this system to achieve opposing motion for 2 x 200 kg loads (i.e. move them closer/ further apart simultaneously). Referring to the picture below...

a. This is easy with ## q = n*e ## ## 3.2 * 10^{-9} = n * 1.6*10^{-19} ## ## n = 2*10^{10} ## electrons b. Total Lead atoms are ## \frac {8 * 6.022*10^{23}} {207} = 2.3 *10^{22} ## I used the Avogadro number. Total electrons = ## 2.3 * 10^{22} * 82 = 1.88 * 10^{20} ##, here i multiplied with...

In order to choose a DC motor according to the article titled: APPYING MOTORS IN LINEAR MOTION APPLICATION by PITTMAN - step 4 : "determine the total reflected inertia (Jt) back from the load to lead screw shaft " . The formula is: Jt = Jscrew + Jload. This calculation relies on the fact...

I'm watching Sean Carroll's video on symmetry [relevant section at around 8:05] He talks about 120 degree rotations of triangles that leave them invariant. Then he proceeds to talk about flipping them with an interesting (at least to me) remark - "there's nothing that says I'm confined to...

Just an effect interesting to think about:

Summary:: How to load the plates with the Lead element in the spectrometer I have a mass spectrometer with lead element which has an electronic configuration 1s^2 2s^2 2p^6 3s^2 3p^6 3d^10 4s^2 4p^6 4d^10 5s^2 5p^6 4f^14 5d^10 6s^2 6p^2. It has 2 free electron, so the ejected electrons go...

Hello everyone, We conducted an experiment with a strontium-90 source and some different thicknesses of lead. With 2.1mm of lead the count rate (corrected for the background) was 0.69 counts per second, 3.0mm 19.7cps 6.8mm 15.4cps 13.8mm 10.0 cps This would...

https://www.nationalgeographic.com/science/2019/12/first-active-fault-system-found-mars2/ One insight on this is seismometers on Mars can provide data driven inferences about Mars deep crust structure with reliably located fault zones. Based on paper presented at AGU FallMeeting 2019 ...

i am reading this paper. after equation 16 the author (Blasone) writes that In the thermodynamical limit this goes to zero, i.e. the Hilbert spaces con- structed over the respective vacuum states are orthogonal. From the second Schur’s lemma [33] it then follows that the two representations of...

Hello, just wanted to know what is recommended after undergrad Physics to get into a career developing electric propulsion systems, or anything to do with Plasmas and future propulsion devices?

Neil Comins in The Hazards of Space Travel states a 40-inch thick wall of lead would be needed to shield interplanetary travelers from the solar wind, coronal mass ejections, and cosmic rays. When lead is constantly bombarded with high energy charged particles, what changes occur to the lead?

I don't know how to understand this: Suppose we measure the spin of an electron with apparatus M. M can yield spin-up or spin-down. According to MWI, M briefly becomes in superposition of measuring spin up and spin down. Extremely quick however, M gets split by the splitting into two universes...

Back in December, I made a thread with a related topic as this titled "Ohm reading when there is a short in the condenser motor". But the question of this thread is distinct from the topic of my "Ohm reading when there is a short in the condenser motor" thread. Therefore, I have decided it...

During episode 2 of the HBO miniseries “Chernobyl”, the search lights held by the three technicians entering the area beneath the reactor eventually go out from exposure to radiation. If the search lights were powered by lead acid batteries, how does radiation interfere with and/or hasten the...

Why does the derivation of the Dirac equation naturally lead to spin ½ particles? The equation is derived from very general starting assumptions, so which of these assumptions has to be wrong to give us a spin-0 or spin-1 particle? I have tried to search for an answer and got as far as this...

Since ΔT is change in temperature, the container and it's contents and the led most have same temperature difference when the led is added. I tried by assuming that energy released by the led is same as the amount that container and it's contents absorb. Meaning Q1-Q2 = 0 => Q1 = Q2. $$ \Delta...

Homework Statement The count-rate from a gamma source is measured to be 1000 counts per minute. When 1.0 cm of lead is placed between the source and the detector, the count rate is reduced to 100 counts per minute. What additional thickness of lead would have reduced the count-rate to 50 counts...

Greetings electro chemistry wizards! A quick speculation here... should be easy to sort out whether feasible. I have nice old pocket watch made of sterling silver that some numpty tried to fix with soft solder - lead & tin i presume but god knows when repair was attempted so it could be newer...

Hi, I am trying to determine the conventional cathode and anode designations for lead acid cells. From what I have researched: Anode is where current flows in the device, or where electrons flow out of. In a secondary cell the designations for anode and cathode are based on the discharge...

Homework Statement Let ##b_1\in \mathbb{R}## be given and ##n=1,2,\dots## let $$b_{n+1} := \frac{1+b_n^2}{2}.$$ Define the set $$B := \{b_1\in\mathbb{R} \mid \lim_{n\to\infty}b_n \text{ converges}\}$$ Identify the set ##B##. Homework EquationsThe Attempt at a Solution I claim that ##B =...

Hey. If i carry out electrolysis of saturated sodium bicarbonate solution with lead electrodes, will the lead electrodes will dissolve to form lead carbonate (or basic lead carbonate if temperature is higher) or the lead ions will migrate from anode to cathode and deposite there? I think that...

Hi, I've seen several explanations for sr on youtube. But they all start off explaining from a different perspective. I was wondering how the fundamental postulates of sr lead to the invariance of proper time between frames, and also what "order" everything is derived in. For example, does the...

<Moderator's note: Two threads merged. Please don't create multiple posts.> can anybody tell me how do I work out how much energy it takes to get an atom of say lead to a given temprature from 0 kelvin

Recently I've been recycling lead from old bullets.But everytime I recast the molten lead to an ingot, its surface is oxidized, therefore I am losing lead every single time I reuse it. Are there simple solutions to this without using an atmosphere of noble gases?

I wasn't sure if this should be in General Discussion, or in this forum. However, since it affects students and it depends on the classroom policy of the instructor, I thought it should be in here. This is something many of us instructors have to deal with, something that was never an issue...

Phonons on their own lead to the common heat equation. One sees that for example in insulators or non doped semiconductors. However in metals (or conductors), the electrons are the ones that are mostly responsible for the heat transfer, which extremely surprisingly to me, is also of the form of...

Which bullet of same momentum is more effective in knocking a bear down? Lead bullet or rubber bullet?

Homework Statement Calculate the fraction of photons absorbed from an attenuated beam of 0.5 MeV photons after it has gone through 1.3 cm of lead? The linear attenuation coefficient of lead for 0.5 MeV photons is 0.5 cm-1. Why is lead a good choice as a material for shielding? Homework...

Homework Statement Homework Equations For lag compensator pole is dominating For lead compensator zero is dominating The Attempt at a Solution So for lag compensator: P1 is closer to origin than Z1, so mod of P1 < mod of Z1 So P1 > Z1 (since the poles and zeroes are negative) And for lead...

Years ago I thought I would take apart a car battery melt all the lead I thought there would be at least 10 or more pounds of lead I only got a little over a pound of lead there was a lot of heavy dirt but applying heat to this material yielded no lead it seems the acid eats or corrodes the lead...

Hi, I have 6 cables. Each cable has 3 wires: zero, phase, earth. Each cable supplies 320W 230VAC heater (I have 6 heaters). I am looking for 1 multi pin connector for all these cables for quick plug in/out. Link to example connectors...

Not only are lead nuclei heavier than gold ones (207 vs 200), but the atoms are smaller (ionic radius 119pm vs 137pm). There is every reason for Pb to be heavier. Why is it lighter? (11.34 vs 19.31 g/cm^3) They both have a FCC crystal structure, so the packing should be equally efficient...

what is the Length of a 60/40 soldering lead that is 0.453kg and 0.8mm in diameter? i could not find the volume of the thing so is there any other way to go around this? i could also not find the density of the 60/40 solder. so yeah I am asking here if anybody knows thank you

Is lead in the US food supply decreasing our IQ? The environmental advocacy group Environmental Defense Fund (EDF) on June 15 released a study about dietary lead exposure, with a focus on food intended for babies and young children. Using a Federal Drug Administration (FDA) database of food...

Homework Statement Homework Equations I = Io e^-ux The Attempt at a Solution 0.75 = 1 * e^-u1 using algebra... u =2.117 I = 1 * e^-2.117*3 I = 0.00175 Answer is apparently 42.2. Can someone tell me where i went wrong? Thanks for any help as always

I changed my breaker box and when I connected the two leads from the pole one is coming in at 120 and the other at 240. I did not change anything between the pole and incoming lead. What could have happened here and how do I trouble shoot / resolve this? The voltage out of the meter on the pole...

I am a lay person, so the physics lesson would only confuse me. I do reloading of ammunition for competitive shooting (Cowboy Action Shooting). I have someone offering to sell lead for melting and casting bullets. He has indicated its source was shielding from hospitals used in X-ray shielding...