Edge Definition and 265 Threads

so just about finishing a report on x ray abosprtion on different materials, generally the linear attneuation coefficent increases with atominc number Z. However silver(47) had a lower attenuation coefficent then zirconium(40) despite having the significantly higher value of Z. With some...

Hello, I am trying to understand an equation stated in the book 'Principles of Protein X-Ray Crystallography' by Jan Drenth (The exact page I am reffering to can be found here...

I believe that the edge of our universe is within our reach because the only way that i see disproves this is for inflation to be faster than light. As this might cause trouble with time, I think that that's the only explanation. If you assume that there's a center, than the edge must be within...

I am self studying physics, and a problem that I have not been able to figure out has been bothering me. Look at the image (also attached): http://imgur.com/xHP2S" Let's say that the side length is 1 m. and the mass is 10kg. The object has no initial velocity and assume there is infinite...

Hi, could someone tell me how the fine edge structure next the the absorbing edge in an XAS arises? from my understanding an XAS is a plot of absorption coefficient against energy of incoming xray. The absorption edge is at an energy corresponding to when the energy is just sufficient to...

Does it make sense to say that the universe has an edge/boundary? Neutrinos are moving all the time with practically no interaction i.e., unimpeded. Where are these reaching after a very long time (t->infinity)?

Hello everybody. Im starting a project on the basic processed undergoing in the edge plasma region. ( I mean, near the walls of a plasma confining device, like a tokamak or so.) I was wondering if you could name some ''things'' I should be aware of in order to make a small PIC code or...

Homework Statement a worker on the roof of a building that is under construction dropped a 0.125 kg wrench over the edge. another workman on the 8th floor saw the wrench go by and determined that its speed at that level was 33.1 m/s. the first floor of the building is 12.0m high and each...

I had been reading several articles on topological insulators (TI) including the Kane and Hasan's 2010 RMP. I am not very much clear about the Z_2 invariant TI. I mean, the even-odd argument proposed by Kane and Male (also argued by S. C. Zhang's group and Joel Moore's group in a different way)...

Does anybody have any experimental data on flat back airfoils. I would like to know the experimental data, experimental setup and initial flow parameters etc. In case if you find it from a report I would be glad if you can give some information regarding the report, such as author, report name...

http://www.edge.org/q2011/q11_1.html I always love seeing the responses to these questions every year.

What is the probability of a fair coin landing on its edge after being tossed by an unbiased tosser? Is there a way to calculate this? Usually the coin will land either heads or tails, but once in awhile, even when not in the Twilight Zone, it will land on its edge...how much is 'once in a...

tif we presume that our finite universe has a boundry. This boundry is due to the pull of gravity. Light will slow down and then come back to us. 'i may be absolutely wrong in this'. My question is that the light we see will be from the stars surface that doesn't face us and star moving away...

Could the principle of Edge Tone used to create a frequency in the airflow of a musical instrument such as the recorder be used to impart a frequency on a much larger air stream? Ideally I would use it in something in the range of a 24" diameter fan with around 130 mph velocity and...

I come from an experimental backround with no astronomy so I am hoping this question makes sense! If the theory of the big bang is correct and space started off at a singularity and is now expanding, there must be an outer edge to this? If this is true then what is it expanding out into...

Forgive me if this has been covered already. If the universe has no center why do astronomers find the oldest stars at its edge? It seems to me that they should be everywhere.

Homework Statement Wheel is hitting edge at a x-component speed of 1.5m/s, what is the force it is subjected to when going over the edge. The wheel is loaded with 200N Btw, the line with an 60 degree angle to to x-axis/ground is the tangent not a ramp. Homework Equations acceleration...

Can anyone explain how to draw a leading edge circle of an aerofoil. Where is the center and what is the radius of the leading edge circle

Hi all, I'm treating a problem concerning a disk containing an additional point mass on the edge. The disk is moving (rotating and translating) relative to another fixed point, meanwhile it's spinning about its axes of symmetry. I'd like to determine the instantaneous angular momentum about...

I studied physics a long time ago and somebody just asked me this question. After trying for a while I couldn't work it out. The situation is this: there's a chain of length $l$ on a table, of which a portion, of length $x_0$, is hanging out (enough so that when you stop holding it down, the...

From what I've read, these things seem important for any student considering graduate school: - GPA, with particular emphasis on higher level classes within a student's major - Good GRE scores, especially on the quantitative section - Some undergraduate research experience, an REU through the...

How will the angle of the sharp edged orifice affect the flow pattern. Most of the angle is encourage to keep at 30 or 45 degree. For a study vortex generation by pushing the water through a sharp edged orifice, what is the optimum angle I should adopt or what consideration should be made...

Time at the "edge" of the universe If a distant galaxy is traveling away from us at the speed of light (due to the expansion of space), does this affect the passage of time? Can we really say that such a distant galaxy is receding at the speed of light and increasing speed the more distant it...

When calculating buckling force i have only found how to calculate it with a force applied to the entire cross section, how can you use Euler's if the force is applied just to an edge or point. Thanks

If Hawking's model is correct then the universe could be regarded as a causally closed system, uncreatable and indestrucible.

I'm reading the paper by D.B. Chklovskii where he quantitatively describes the appearance of strips of incompressible electron fluid in a 2DEG when a magnetic field is applied to it. What I don't get is the relationship between these strips of incompressibility and the edge states in the 2DEG...

http://books.simonandschuster.com/Tear-at-the-Edge-of-Creation/Marcelo-Gleiser/9781439108321 Overturning more than twenty-five centuries of scientific thought, award-winning physicist Marcelo Gleiser argues that this quest for a Theory of Everything is fundamentally misguided, and he explains...

Video: https://www.youtube.com/watch?v=dBS1NRsYuF8 Pretty cool. You can't beat the sound of a Huey though!

From this example Anti-Aliasing section 22.4.1 http://http.developer.nvidia.com/GPUGems2/gpugems2_chapter22.html what does the following equation represent and how was it derived? k = \frac{2}{(2r+w)\sqrt{(x_0 - x_1)^2 - (y_0 - y_1)^2}} I assume the 4 sets of linear equation...

If two masses m1 and m2 (in kg) are a distance d (in m) apart, then the force F (in N) of gravity is F = Gm1m2/d2, where G = 6.67 × 10−11 Nm2/kg2. If the mass of the Earth is 5.97 × 1024 kg and the radius of the Earth is 6380 km, calculate the work required (in J) to send a mass of 1 kg to the...

The coefficient of statis friction between a rope and the table on which it rests is 0.3. Find the fraction of the rope that can hang over the edge of the table before it begins to slip. This is an extra credit problem so we haven't learned this yet. I don't know where to start but I'm...

So there must be an edge, a point where matter stops and from there on in is a complete vacuum. The universe is supposedly expanding at an estimated 50-100 km/s/Mpc which is slower than light speed. So this means that light from the universe goes into a place (outside of the universe), that...

What exactly is meant by "Fourier techniques" for edge detection? I'm trying to work on an edge detection assignment for a Fourier Analysis class. I've nailed every bit of it up to this point, but now the assignment is wanting me to do edge detection via "Fourier techniques." No amount of...

As I'm reading my morning news stories, I can't help but feel like everything is slowly building up to some sort of great climax. That everything is getting so bad or so good as the days progress eventually everything has to maximize or peter off, before everything becomes incredibly boring or...

Suppose the water at the top of Niagara Falls has horizontal speed of 3.59m/s just before it cascades over the edge of the falls. At what vertical distance below the edge does the velocity vector of the water point downward at a 64.1 degree angel below the horizontal? From this information I...

Homework Statement A rock is projected from the edge of the top of a building with an initial velocity of 18.4 m/s at an angle of 35◦ above the horizontal. The rock strikes the ground a horizontal distance of 96 m from the base of the building. The acceleration of gravity is 9.8 m/s2 ...

Hi, I have measured some spectrums from various gamma sources and I was wondering what kind of fitting I should do to determine the Compton edge. I have access to Logger Pro, Excel, and mathematica. I have fit the photopeak with a Gaussian so I know the uncertainty in the Compton edge, I...

Homework Statement I've made a picture of the situation: http://img11.imageshack.us/img11/7177/drawing1m.jpg I need to find the expression for the start velocity v0. The ball should exactly hit the corner. The function should have the distance L (Which both is x-distance and...

Why is the b field inside a thick toroid largest along inner edge and smallest along outer edge?

Currently we see to about 15 billions years, determining that to be the edge of the universe. Could that just be the limit of what we detect can travel? It experiencing "friction" or other obstacles along it's travels.

hi. I am an undergraduate physicist and don't have that much exposure to cosmology but i was watching a BBC Horizon episode on M Theory and that the Big Bang was believed to be the collision of two parallel universes in the 11th dimension and that the combining of the p-brane ripples formed...

Back when I was knowlegable about the automotive industry, there were high-quality oil brands, and then there was the low-grade stuff. One could tell by checking the SAE ratings. I am told that today there is very little difference between any two brands of oil; that the only real choice is...

Homework Statement A projectile is fired from the edige of a building with initial velocity of v0=10 m/s at an angle of 45 degrees. The rojectile rises and then lands oln ground at point P as shown, which is 35.4 meters away from the base of building. A) Find the Y component of the projectile's...

Homework Statement A point mass m is attached to the rim of an otherwise uniform solid disk of mass M and radius R (in the diagram mass m is in contact with the ground). The disk is rolled slightly away from its equilibrium position and released. It rolls back and forth without slipping...

http://www.sciencedaily.com/releases/2009/04/090409142301.htm Where does space begin? Scientists at the University of Calgary have created a new instrument that is able to track the transition between the relatively gentle winds of Earth's atmosphere and the more violent flows of charged...

I know this question sounds far to naive but anyway, "Is the edge of the universe the begging of time" My rational is simple. The further you look out in space the faster things are moving away from us. Therefor I would suspect at the edge of the universe time would hardly move at all...

I know that there are several theories out there about how old the Universe is and how big, etc. I also know there are theories related to Mbranes (string theory?) that state that there are "pages" of universes that sit side by side (that's the easiest way for me to think of it) and that there...

Homework Statement A light ray leaves point A in the figure, reflects from the mirror, and reaches point B. (Intro 1 figure) figure attached How far below the top edge does the ray strike the mirror? Homework Equations The Attempt at a Solution im not sure exactly where it...

Homework Statement A man (mass m1 = 100 kg) stands at the fringe of the large rotary table (radius R = 5 m, massm2 = 100 x m1), which rotates at a frequency of 10/min. The man goes along a radius line towards the table center until he reaches the rotation axis. The spatial extent of the man...

http://edge.org/q2009/q09_index.html At least one of this year's "big change coming" predictions had to do with quantum gravity. I'd like to collect links to those with some bearing on QG, if there are others. The one I just read, which impressed me as reasonably likely to happen and described...