Green Definition and 281 Threads

As in title: Plugging in the definition is straight forward, I am too lazy to type, I will just quote the book Fetter 1971: Up to here everything is very straight forward, in particular, since we are working on free electron gas, ##E=\hbar \omega## However, I have no idea how to arrive...

I think I has observed it a few weeks ago (maybe it was something else), and it was long & bright, but now it's barely visible . (I'm using a 12X, 60mm binocular.)

Starting at about 15:15 in the video, he talks about a "fuel", related to a quantum field, that provides outward rush of space, and its virtually possible to use up. What is he talking about, anyone know? Sounds a little funny to me! Thanks.

https://github.com/TheOdinProject/css-exercises/tree/main/foundations/02-class-id-selectors I’m doing this assignment of The Odin Project. But the two colors aren’t working. Here’s my code: index.html: <p class="odd">Number 1 - I'm a class!</p> <div ids="second">Number 2 - I'm one...

Upon reading a book titled The 39 Clues, one of the main characters finds a vial of green liquid and holds it out into a thunderstorm to be struck by lightning to "charge" it. Once it's struck, it is now glowing, appearing as almost pure light and not even warm to the touch. I understand this...

Wired has a new article that seems interesting. https://www.wired.com/story/can-green-ammonia-be-a-climate-fix/ The part about eliminating the use of methane in ammonia production sounds good to me. This could also be a good case of switchable demand - if the wind or solar power dips, the...

I have been using Visual Studio Code for a couple months now and it has been fine. When I want to run some code, there is usually a little green triangle button in the top right corner that I can click on. A few days ago, that triangle turned white only for Python files (it is still green for...

What's the derivative of deformation gradient F w.r.t cauchy green tensor C, where C=F'F and ' denotes the transpose?

Plant leaves only appear green because they absorb the red and blue wavelengths of light and reflect green away. Is there an intrinsic and innate reason for this that relates to the physics of light? Maybe green wavelengths are inefficient at storing energy in chemical bonds? Have plants simply...

"Consider a string of length L that is connected at both ends to supports and is subjected to a load (external force per unit length) of f(x). Find the displcament u" https://i.stack.imgur.com/yVIDG.png We need to solve this: $$Tu_{xx} = f(x)$$ subject to $$u(0)=u(L)=0$$ But i don't understand...

Was spraying oven cleaner on a somewhat rusted grill and my son, who is taking AP chemistry, asked about the green color that appeared. googled sodium hydroxide + iron oxide and got this FeO + 4NaOH = Na₄FeO₃+ 2H₂O but can't find any info on Na₄FeO₃ - would this have a green tint, and is...

Hi everyone. Using the Green function, I want to obtain the density of states of a one-dimensional (linear) lattice. Depending on the problem conditions, we will have an iterative loop with 4,000 data for the energy component and a iteration loop with 2,000 data for the wave number component. In...

I soaked the following school medallion in water with salt for 20 plus years in the attic and at that time I didn't know copper could corrode and make green oxides. I also didn't think about it much and just forgot about it. I brought it down just today. I read just a while ago that hot...

Our Windows 7 32-bit desktop PC is fitted with an Asus P7H55-M LX motherboard. It was working fine till yesterday evening, but from this morning, it won't turn on. (By this, I mean that it is not even starting the boot; the fan on the processor won't run.) My first guess was the PSU. So I...

I was watching a grey squirrel the other day who stood out amongst green leaves, and wondered whether there was a reason no mammals have evolved green fur (AFAIK?)? I'm aware there are a couple who allow green algae to grow in their fur (sloth and polar bears). I mean we have weird things like...

I'm supposed to make a project on "Green Chemistry".so if you guys have any suggestions for a good book?

A conducting sphere of radius a is made up of 3 different shells, upper part a/2 z -a/2, the middle part -a/2 z a, the lower part -a z -a/2 where the center of the sphere is at the origin. The upper part V and the lower part has -V potentials, while the mid part is grounded. Find the...

What are salt that have green colour?

could anyone explain why in the page of book this figure is related to hartree-fock? I mean why if t1>t2 we have these possibilities? and why not particle propagate from x2t2 to x3t3 instead x3t3+?

https://www.rollingstone.com/music/music-news/peter-green-fleetwood-mac-guitar-hero-1034049/

I got stuck here, how to integrate e^(y^2), I searched but it's something like error function

If I have 237 buckets, and there are n green balls distributed randomly over those buckets, and I put 34 new red balls randomly in those 237 buckets, what is the formula for the probability that x green balls share a bucket with a red ball? Any help appreciated.

https://www.npr.org/2020/05/22/858800112/herd-like-movement-of-fuzzy-green-glacier-mice-baffles-scientists Check out the article - good photos. These moss balls, plants, are found with rarity in several glacier/ice fields world wide. This article is about researchers trying to understand how...

I was wondering if there is a way to deduce the solution of the potential of a charge outside a sphere given by the image method, though Green functions. Because of a Dirichlet condition (GD(R,r')=0), I know that a solution can be written as GD=Go+L, where ∇2L=0. But in order to approach this...

I'm asking the question because I'm interested in learning more about how ionic compounds behave in and around electric fields. I'm not actually going to make the proposed electret. The color of the Jello is irrelevant, and Jello may not yield an everlasting electrect, so it's more about the...

If I paint a ball in red and green chequer pattern and with 50% coverage of each, then spin the ball then it looks white. If I make the pattern with smaller and smaller chequers, does it stay white and how small can the pattern be before it turns a different colour? Once the pattern is a...

My fundamental issue with this exercise is that I don't really know what it means to "show that X is a propagator".. Up until know I encountered only propagators of the from ##\langle 0\vert [\phi(x),\phi(y)] \vert 0\rangle##, which in the end is a transition amplitude and can be interpreted as...

I get the basics of green screening. The processing software recognizes a small range of green and can substitute a different image where it occurs. Here's what I don't get: if a subject is standing in front of a green screen, they will have reflections of green. Notice that, in the...

I came across an example of a solution to finding the potential of a charged layer using the Green function (here, pdf). The standard algorithm for finding the Green function by boundary conditions for many problems is understandable: \begin{align*} G_\mathrm{Left} = Ax+ B \\ G_\mathrm{Right} =...

The Feynman propagator: $$D_{F}(x,y) = <0|T\{\phi_{0}(x) \phi_{0}(y)\}|0> $$ is the Green's function of the operator (except maybe for a constant): $$ (\Box + m^2)$$ In other words: $$ (\Box + m^2) D_{F}(x,y) = - i \hbar \delta^{4}(x-y)$$ My question is: Which is the operator that...

Hi Everyone, I'm doing research in Implanted Devices in Human Body (Sensors, Hearing Aid, Pacemaker) for my college course. I've started with FitBit that uses the PPG Principle. But I'm struggling to understand why the FitBit uses both Green and IR LED whereas the sensor at the receiving end is...

AIUI, there are these 3 types of algae, with blue-green algae being technically bacteria, green algae being plants, but what are red algae?

In a container, there are some blue, red and green marbles. There are twice as many blue marbles as red marbles, and there are 3 more green marbles than blue marbles. a) There are z red marbles. How many green marbles are there? my answer: z + 2z + 6z = 9zb) There are 19 green marbles in the...

Homework Statement If a green laser is (wavelength = 532nm) sent through two slits with a separation of 127 um, how wide (in total) would the 11 green dots formed be if they were projected onto a screen 1.25m away from the slits? Refer to this diagram sorry for bad quality...

Homework Statement For a high school physics class, I chose to build a tesla coil for a real world application assignment. I was able to build it fairly easily and it turned out great. Before presenting to the class next week, I've been seeing its effect on different types of light bulbs and...

I was studying evolution and speciation and an example was given in my textbook. It said that there is a species of red beetles and through variation a green beetle is formed and then is naturally selected as red beetles are easily seen by crows and green are not. My question is where does the...

While experimenting with an idea for a demonstration in surface tension, I ran across something interesting. I placed a drop of red food coloring on a glass slide, and let it dry. Once dry, the residue was a light green in color, but when held up to let light pass through it, it looked red...

Gilligan has 16 green marbles, 50 blue marbles and 60 red marbles. What is the probability of randomly selecting 2 green marbles? What is the set up?

I was driving the other day, and I was about to go past a green light when it turned yellow, so I sped up. I got past the light but but it got me wondering, how fast would you need to go for a red light to appear green due to the Doppler Effect. (Excuse me if this question doesn't belong in...

White light is usually stated as having a uniform spectrum (eg all frequencies at same intensity). However the human eye is more sensitive to green light than other colours. So why doesn't white light appear slightly green?

Hello, Before I begin, a lot of the math I try to describe in this post is stuff I worked out myself and have scribbled down. If something looks fishy or doesn't make sense, it could very well be totally wrong! Apologies for any confusions in advance. Consider a slab of linear isotropic...

We are wondering if there is an ideal ratio of simple green + glass cleaner to get the bugs off & keep it streak-free. Thought there might be a chemist with the ideal ratio. We will experiment and let you know what happens.

Hello Why the uranium glass glows green if it's under UV light? The most accurate thing I have found it's a brief history of uranium glass: somewhere it's said the more uranium oxide you put in the glass, the more intense will be the green light when exposed to UV light. Thank you for your...

I'm new to this so please correct me if I'm doing this wrong. I'm curious to know about what practical uses are there for nuclear fusion other than a green power source.? I've already seen a few readings and a video from a Michel fellow about how it works, and it's fascinating stuff I'm not much...

Homework Statement A golfer strikes a golf ball at an angle of 17 degrees above the horizontal. With what velocity must the ball be hit to reach the green which is a horizontal distance of 250 m from the golfer? It is at the same height as the tee. Homework Equations trig equations...

Green functions are defined in mathematics as solutions of inhomogeneous differential equations with a dirac delta as the right hand side and are used for solving such equations with a generic right hand side. But in QFT, n-point correlation functions are also called Green functions. Why is...

Are there differential equations that, for some reason, don't have a Green function? Are there conditions for a DE to satisfy so that it can have a Green function? Thanks

I'm getting ready to do some testing, and need to decide which lasers to use . I need both left and right circularly polarized laser light . I was told that green diode lasers, the kind readily commercially available (usually around 200 - 500 mW.) , are LEFT CPL. 1. Is that usually true, and...

Referring to LEDs as I'm not aware of any other "colour-producing" light, does blue light use more energy than red light? Planck's formula (E=hf) leads me to believe that blue light would drain a battery quicker than red, due to its higher frequency. Surely a device emitting blue light would...

Hi People, I'm being scheduled to take the Six Sigma Green Belt Certification exam sometime in the summer 2017. They already have the registration deadlines/dates up for 2017 already. It's an Open-book, open-notes, calculator-allowed test according to what I've been reading online. I'm...