Green Definition and 281 Threads

According to the History Channel documentary How the Earth was Made (DVD), Earth's early oceans were green, b/c of their (different) chemical composition. For example, they had more dissolved Iron, and CO2. CONCLUSION: Earth Early Lifeforms were confined to the Oceans, for lack of an Ozone...

Hi Everyone, My teacher gave me a project to created anything that need not to be build out physically. I gave the tittle green planet. So the idea is that one could create a VACUUM tunnel from the north to south pole (or any 2 points that is a diameter of the earth) and a "vehicle"...

Entropy is said to always increase. But do not green plants reverse entropy? Seems to me that everything they do increases order, down to the molecular level.

Hello, I have a high power RGB LED with common anode. I want to have 3 of them in series, and put them on 15V power supply. And I want to switch green color on, and red color as well (something like a normal traffic light) Here is the problem: Given that three LEDs are in series, and are...

Stars seem to occur in almost every color, from red to near violet, but not green. Why are there no green stars?

Hello, I don't fully understand the meaning of Green function, and how one should use it. According to Jackson's "Classical Electrodynamics" - 'the method of images is a physical equivalent of the determination of the appropriate F(x, x') to satisfy the boundary conditions'. Where Green...

i am having problem in calculating pKa in my experiment,a formula of pKa=pH + log10 [HB]/[B] my data obtain only gotthe pH of HB,that is 5.17 how can i calculate the pKa?? [HB]=concentraion of undissociated form indicator [B] =concentration of dissociated indicator

Hey folks, I'm trying to find the Green function for the equation -\partial_\mu \partial^\mu \phi = K where K is some source term. Its a 2D problem with the wave confined to a rectangular cavity where the cavity is located at z = 0 and z=a. This tells me that G|_0= G|_a=0 I've pretty...

If I subscribe to this service, I get my electricity from solar and wind power. But how do I know I'm getting green electrons into the meter?

Hey folks, I'm not really sure which forum to put this question in but I figured this was probably the best as it deals with issues of regularization. I'm reading Miltons 'The Casimir Effect'. In chapter one he derives the Casimir energy for a massless scalar field by employing...

Hey folks, I'm trying to get a handle on my old Nemesis, Green functions. I have a massless scalar field confined between two parallel plates separated by a distance a (in the z dimension) and the field satisfies Dirichel BC's. Basically I'm trying to work from line 1 of a book to line 2 (K...

Suppose \phi is a scalar function: R^n\to R, and it satisfies the Poisson equation: \nabla^2 \phi=-\dfrac{\rho}{\varepsilon_0} Now I want to calculate the following integral: \int \phi \nabla^2 \phi \,dV So using Greens first identity I get: \int \phi \nabla^2 \phi \,dV = \oint_S \phi...

Red light mixed with green light produces yellow light. Yet, a red photon and a green photon don't combine to make a yellow photon (or two of them). Can someone explain this?

Homework Statement Negelcting internal heat sources, the surface Temperature of the Earth is calculated to be 255 K. Its actual mean surface Temperature is 288 K. The additional heating results from the greenhouse effect. Regarding this as an internalk heat source, calculate that heat source...

https://www.greenbags.com/?cid=402572 On face of things this claim sounds reasonable to me, but really I have no idea. They claim to be good for ten uses.

Homework Statement A mixture of red light (wavelength vacuum = 652 nm) and green light (wavelength vacuum = 477 nm) shines perpendicularly on a soap film (n = 1.333) that has air on either side. What is the minimum nonzero thickness of the film, so that destructive interference removes the...

find the eigenfunctions and eigen values of the next equation: d^2y/dx^2+u_n^2y=0 where y(0)=0=y(pi). Now find the green function of the above non-homogeneous equation, i.e: d^2G_{\lambda}(x,a)/dx^2-\lambda G_{\lambda}(x,a)=\delta(x-a) where a is in (0,pi) and lambda doesn't equal the...

This week, people are free to interpret the theme as they wish, although some has taken it into a direction that I never thought of. So please vote for the picture that best represents our theme : Green Acres 1. larkspur 2. turbo-1 3. hypatia 4. BobG...

I need to find the green function of (\frac{d^2}{dx^2}-k^2)\psi(x)=f(x) s.t it equals zero when x approaches plus and minus ifinity. Now according to my lecturer I first need to solve the homogenoues equation, i.e its solution is: psi(x)=Ae^(kx)+Be^(-kx) and G(x,x')=\sum...

[FONT="Comic Sans MS"][SIZE="5"]Green Acres Green acres is the place for me. Farm livin' is the life for me. Land spreadin' out so far and wide Keep Manhattan, just give me that countryside. New York is where I'd rather stay. I get allergic smelling hay. I just adore a penthouse view...

I am in the unique position of being able to implement ideas for green homes immediately for production. If you have any ideas that you would like to share, we will consider your ideas and may use them. It is a chance to help change the world a little bit. Yes I do benefit from this but not...

Not sure if this is the best place, but it's also my first post, so meta-answers about where I'm supposed to put this business are welcome too. I'm a physics student, and I'm interested in learning about Green functions, but I sold back the Boas book that I used for my math methods class (we...

http://www.medicalnewstoday.com/articles/73473.php

I am a physics major, what would be a possible route into green technology? What kind of grad school would I look too? Phd physics or engineering? And what would I specialize in at grad school ? I guess there are all kinds of technologies that could possibly be used ie: solar, hydorgen...

Glass is Green? when the glass is viewed at their edge , it looks green . 1.why it is green when viewed at the edge ? 2.Why its not green when we view other than the edge ? i think polarization is the effect but if so,how does it take place . please help me in this...

so how much of a **** do you actually give about the whole 'green' thing? is it really worth worrying about in your opinion? someone just sent me this http://www.guardian.co.uk/environment/treadlightly?CMP=OTCTreadLightly2 you register, they give you 'green' tasks to do, and you...

i am a total newbie here...i understand basic principles like supercooling, phase change, etc, but otherwise a total dummy, i have equivalent to 1st yr university in chem, but that was a long, long time ago. so go easy on me. i am trying to find out the difference btwn sodium acetate...

Hey folks! I'm starting with the Lagrangian of a massive scalar field and have found an expression for the expectation value of the energy-momentum tensor. <T_{\mu \nu}>=(\partial_\mu \partial_\nu-\frac{1}{2}(g_{\mu \nu}(\partial_\mu \partial_\nu+m^2))G(x-x') let say I have some Green...

Does anyone have one of those military grade green lasers that can set things on fire? I've seen people build them but I don't have a solder iron :(

Is it possible to burn anything with a 5 mW green laser?

A novice golfer on the green takes three strokes to sink the ball. The successive displacements are 4.00 m to the north, 2.00 m northeast, and 1.00 m at 30.0 degrees west of south. Starting at the same initial point, an expert golfer could make the hole in what single displacement? I drew...

I bought this stand up scooter for $850. It's made by a company called http://goped.com" . It can go upto 20mph and I weigh 142lbs. But the problem is, as with all electric scooters is they get low range. Mine get's about 10 miles and it runs on stock SLA batteries packs. Picture...

Heads up . . . I have not formally studied quantum physics, but I do read about it and watch videos by some of the greats. I understand the conflict between the "micro" and "macro" physics, but I do no understand most of the details of quantum physics. Now, Tom Green enters the picture. He...

Those familiar with Alex Stef's page with the list of online lecture notes on mathematics and related topics may want to update their bookmarks. This is new site: http://users.ictp.it/~stefanov/mylist.html Those who are coming across this site for the first time may want to bookmark it...

This is the dreaded final round. It will be a difficult one. Good luck to everyone! Please vote for the picture that best represents our theme: the color GREEN. 1. SpaceTiger http://www.astroskwurl.net/PF/Green.jpg 2. Janus...

This is the 2nd group in this contest. Please vote for the photo that best represents our theme for this week, which is the color GREEN. 1. Moonbear http://img59.imageshack.us/img59/3446/greenhi9.jpg 2. Integral http://home.comcast.net/~Integral50/Photo_contest/HPIM1001a.JPG 3...

This is certainly going to be another difficult contest to vote on, even for the first round. You have one vote to cast in each group. Please vote for the picture that best represents our theme, which is the color GREEN. 1. SpaceTiger http://www.astroskwurl.net/PF/Green.jpg 2...

[FONT="Comic Sans MS"]Green With Envy Just in time for St. Patrick's Day this weekend, our theme for this week will be the color GREEN. Your picture must have the color green as the dominant color in the picture. Good luck of the Irish. [SIZE="4"]Contest Rules: 1. Any digital photo...

Question 1) Integrate y^2 dx + zx dy + dz, along the circle x^2 + y^2 – 2y = 0 to (1, 1, 0) I am not sure how to begin on this problem. Would it be beneficial to convert to polar coordinates? The thing that is throwing me off is the fact that the circle’s equation is not the normal circle...

Hey, I am trying to find a GF for the function: y''+\frac{1}{24}y=f(x) The function is bounded by: y(0)=y(\pi)=0 I have followed a math textbook that goes through the exact process for the function: y''+k^2y=f(x) and have found a nice looking general solution...

Homework Statement Hey folks, I need to find a Green function for the equation: y'' +1/4y = f(x) With boundary conditions y(0)=y(pi) = 0 The Attempt at a Solution I tried some combination of solutions that look like sin(kx) and sin(k-pi) and looked at the strum liouville...

I saw a bright green meteor yesterday. What would cause a meteor to be bright green? Is this common?

Photosynthesis occurs in all plant life and is responsible for making them green. Why are not all plant life green. I.e. flowers can be yellow, red and some leaves too like the leaves of Poinsettia. Is the reason because no photosynthesis goes on in them? Or is something else more dominant...

http://www.detnews.com/apps/pbcs.dll/article?AID=/20061129/UPDATE/611290443

Hi, I have a basic ODE: y''(x)+\frac{1}{4}y'(x)=f(x) on 0<x<L With Boundary conditions: y(0)=y(L)=0 For which I would like to construct a Green Function. Rather than just plain ask for help, I'll show you what I've been thinking and maybe someone wiser can help/correct me...

I am demonstrating the mean value theorem, which says that for charge-free space the value of the electrostatic potential at any point is equal to the average of the potential over the surface of any sphere centered on that point. I have already found one way to do this, but would also like to...

I don't have a clue on where to start this as i don't know what other figures to use. Dry air will break down and generate a spark if the electric field exceeds 3x106N/C. How much charge could be packed onto a green pea (diameter 0.75cm) before the pea spontaneously discharges?

How do I treat a goldfish pond green with algae? Visibility is ~2 inches. It's not the wall coating I'm concerned about, it's the water itself. I know how I'd treat it indoors - with a scraper and a water change, but that won't work in a pond. (Well, I suppose a water change would help...)...

I need a list of Green functions, for different types of equations and dimensions. I have tried to use google but with no success.

http://www.hsrmagazine.com/hotnews/65h101448772375.html