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|Saturday, October 4th, 2014|
Cosmogony and gravitation - Inverse hypothesis
Since the beginning (of which never was) and prior to appearance of the first signs of the Universe in space surrounding us there was a continuous emptiness. And all so also proceeded if this emptiness had no opportunity to be divided into substance and energy.
At the first there were feeble one-dimensional perturbations of a vacuum. The most part of such perturbations collapsed back, but some perturbations had an opportunity because of higher energy to promote further in space, having occupied energy from environmental vacuum. At the end of distribution as a tribute to the generated space, these one-dimensional strings left mesons.( Collapse )( Collapse )( Collapse )Wikis
Le Sage's theory of gravitation
|Saturday, May 17th, 2014|
Ohm’s law states that the current through a conductor between two points is directly proportional to the potential difference across the two points. Introducing the constant of proportionality, the resistance, one arrives at the usual mathematical equation that describes this relationship:
where I is the electric current, the electric conductivity G, U is the voltage and R is the electrical resistance.© toptunow_86
Introduction to Nuclear Physics - part 1
It is well known that the nucleus consists of nucleons (protons and neutrons) and that has a very high atomic weight. Between the particles in the nucleus has a very strong nuclear interaction, much stronger than the magnetic force or gravity, but it works only over short distances. Therefore, the nucleons in the nucleus and keep it to fall apart.
Some nuclei of atoms - mostly unstable - emit radiation at high frequencies. This radiation is called radioactivity reaches higher frequencies than X-rays. When radiation nucleus disintegrates and turns to the kernel of another element. Unstable elements tend to break down to a more stable elements. Stability of the element is determined based on the ratio of the number of protons and neutrons. Elements with a ratio of 1 are stable (most stable element in the universe is iron), elements with a ratio of up to 1.5 are unstable and elements with a ratio greater than 1.5 are highly unstable. Substances consisting of atoms of these nuclei are called radionuclides - may be either natural or artificial.
Types of radiation
Alpha AZX → A-4Z-2Y + 42α
From the equation can be deduced that it is a bundle of speeding helium nuclei.
Specific example:23994Pu → 23592U + 42 α
Alpha radiation has the smallest frequency radiation, it's absorbed by sheet of paper.
Beta +AZX → AZ-1Y + 01e
Specific example: 3015P → 3014Si + 01e
It consists of a stream of positrons, it's absorbted by the aluminum sheet.
Beta -AZX → AZ+1Y + 0-1e
Specific example: 21084Po → 21085At + 0-1e
It consists of a stream of electrons, it's also absorbed by the aluminum sheet.
GamaAX → AY* + 0-1e AY* → AY + γ
Specific example: 6027Co → 6028Ni* + 0-1e 6028Ni* → 6028Ni +γ
This is electromagnetic radiation, it's absorbed by a layer of lead.
Logical it consists of a stream of flying neutrons, it's absorbed by very thick layer of water or concrete.© toptunow_86
|Friday, February 15th, 2013|
Is there anyone who has any seismology knowledge/experience here? I have some questions about why earthquakes make noise.
Background: I live in Christchurch, NZ, and we get a lot of quakes nowadays(!). Our quakes are very shallow - typically 5-20km deep, and the horizontal distance to the epicentres is generally between 2-30km. I would say that roughly 40-50% of the magnitude 3+ quakes we get are preceded by audible rumbling. When I google for what causes this, I get condescending answers like "I'm not a scientist or anything, but I think it's pretty obvious that it's the ground breaking apart and the plates shifting." (thanks, Yahoo Answers; I'm pretty certain that the ground isn't breaking apart under my house
Elsewhere, I've found a suggestion that higher frequency (audible to humans) vibrations reach the surface when the quakes are shallow. That's helpful - but then, why don't all our quakes make noise, since they're all shallow? Also, I have noticed that often a quake will be very noisy where I am, but my partner in a different part of town doesn't hear anything. Is it possible that there's something about local ground conditions that affects the noise, not just the quake itself? (Or am I simply better at hearing quakes than my partner?)
I have another question, again based totally on anecdata (sorry!): Our city got hit on the 22nd Feb 2011 by a 6.3 quake which was very shallow, perhaps 5km deep, and very close - 10km from the city centre. That night of the 22nd, the bigger aftershocks (magnitude mid-4s) were extremely audible, not just when approaching, but also when receding, and they had a very obvious direction to them. But the shocks nowadays do not seem to have such an obvious direction to them, and I no longer hear them receding. Why not?
Thank you in advance :). Current Mood: curious
|Monday, January 7th, 2013|
Planck Units / Planck's Constant / Planck Scale
I was wondering if anyone who actually knows his or her stuff might be willing to have a bit of a dialogue about Planck Units, Planck's Constant, and/or the Planck Scale with a total layperson?
I'm trying to come to a better understanding about these things, but reading articles about them is somewhat unhelpful. I have some questions, but they might not make sense given my current understanding of these matters and I hope that some dialogue will improve both my understanding and my questions.
For instance, the Wikipedia article says:...these units are also known as natural units because the origin of their definition comes only from properties of nature and not from any human construct.
So, to me this seems to imply something about nature
and not something about the way we observe or measure nature. Is it a Planck's Unit that implies a discrete as opposed to continuous universe?
I recall either reading about or having someone tell me about how Planck's Constant--or maybe it was the Planck Unit or maybe the Planck Scale--(and here how do these three relate to one and other?) is the smallest interval we are able to measure
. If this is so can anyone explain why?
Further, if this interval is the smallest we are
able to make observations or measurements at, then doesn't this limitation imply something about our methods as opposed to something about the natural world
I'd appreciate any helpful input regarding the above and I might have more or follow up questions: please, walk the Planck with me (I know, *groan*, right?).
Curiosity didn't kill the cat, opening the box did!
|Saturday, December 29th, 2012|
nice comment from 4_4_4
4_4_4 please go to my personal journal if you haven't lately. Would appreciate feedback. Thanks waffler_61
|Tuesday, December 18th, 2012|
would some nice person tell me if my personal posts can be shifted over to this community w/o having to retype them into it, and if so how to do it? waffler _ 61...........firstname.lastname@example.org...
......thanks Current Mood: amused
|Monday, December 17th, 2012|
If information is the underlying structure of reality, how did this process come about? If there ever was was a void, (that is a true void), with nothing in it such as matter, energy.......not even the dimensions, how could anything get started? Allowing that there was a void, and I emphasize the word "a", this allows a semantic discription to read : "there was ONE void".Meaning that the void had some starting information in it, namely that there was a "one" that an observer could attach to the particular concept. I see this as a default setting that cannot be avoided, even though it's a pretty shaky idea, how else could everything come from nothing except through some process that came from quasi-theoretical principles? So, if this one bit of imaginary information was imbedded in the void, what could cause any expression of it's presence? I propose that there was a similiarly theoretical collary to this bit and that it took the form, by our understanding, of a point. A point can be described as a dot or a circle or a sphere, and what have those things in common? They all would describe the geometric requirements to produce PI, which has the same outcome regardless of the size of the "dot". Since PI produces an endless string of information, what would happen? If information accumulated within the context of the void, eventually enough information would "code" for all the matter, energy, force fields. and etc......even the dimensions. The informational data stream would eventually code the dimensions, allowing the informational contents of the void to emerge, finally having been freed from comfinement. This could have caused the big bang. Logic would dictate that in this scenario, the dimensions would have been the last thing worked out, as all the "stuff" was released at that moment. The containment breeched, the informational black hole exploded. Yet energy(dark) continues to be produced, and in my journals I suggest why. I have several other posts in my journal concerning some of the logical extensions of this theory dealing with time, quantum (why the quantum?) mechanics, why hasn't another big bang ocured, dark energy, the evolution of logic in a pre-mathematical proto-void. I hope you can get into my journal, I'm new to this site and hope I don't have to retype every post of mine to this one. I'm stll learning to navigate the site. thanks waffler_61. Current Mood: awake
I'm intrested in talking about ideas stemming from the it from bit concept, Current Mood: awake
|Monday, September 10th, 2012|
Are there such special books that contain physical problems for students. Can you give me examples of them which you like more?
|Sunday, November 20th, 2011|
So I have been working on designing a Tesla coil. But I'm having trouble understanding a few of the concepts. In particular is this idea of 'tuning' resonant frequency of the secondary coil to create the induction in the primary coil. Can anyone explain this in a bit more detail? Or point me towards a website that explains it? (apparently my google-fu does not work on Tesla coils)
Thanks so much!
|Tuesday, October 11th, 2011|
Physica Scripta Article Request
I'm looking for a scanned or digital copy of the article listed below; our library has all the Physica Scripta volumes but this one apparently. If you can get a copy, drop me a comment, and I'll shoot you my univ. email.
Hans Karlsson and Ulf Litzén, "Revised Ba I and Ba II Wavelengths and Energy Levels Derived by Fourier Transform Spectroscopy," Physica Scripta, vol 60 321 (1999).
|Saturday, September 24th, 2011|
|Thursday, September 15th, 2011|
Looking for Physics Books
I'm looking for book recommendations, particularly EM and QM (or modern physics in general), that are strongly oriented towards relating physics to the real world. Specifically, something that goes into detail concerning the historical/experimental basis of the theory and has examples or explanations that are more or less directly applicable to laboratory work. They can be undergrad or grad level.
I am considering Morrison's Understanding Quantum Mechanics. Can anyone comment on the contents of this book?
|Saturday, June 11th, 2011|
Radioactive Iodine Activity
I'm trying to help someone with this physics problem and it's not going well...
A patient with thyroid problems has radioactive iodine-123 deposited in his thyroid gland. If the iodine-123 has an initial activity of 2.4 MBq, what is its activity after 18 days?
This has got to be easy but I have something going conceptually wrong. The practice version is slightly different and I know the answer so I will demonstrate with that one:
A patient with thyroid problems has radioactive iodine-123 deposited in his thyroid gland. If the iodine-123 has an initial activity of 2.7 MBq, what is its activity after 15 days?
Since the unit Becquerels is a measure of number of nuclear decays per second, I just assume that it can be used the same way that grams is used in the following equation, since grams of radioactive atoms should be directly proportional to the number of nuclear decays per second.
A = A0e-(lambda*t)
, where lambda = ln(2)/half-life
The half-life of I-123 is 13.13 hours, so lambda = 0.0527911....
The time t = 15 days * 24 hours/day = 360 hours
= 2.7E6 Bq
Therefore, A = 2.7E6e-(0.0527911*360)
= 1.5055E-2 Bq, or 15,055 microBq
The answer, however, is supposed to be 16,700 microBq.
Is my assumption incorrect? Should I be using a different formula?
Thanks for any help.
|Saturday, May 28th, 2011|
Thinking about Energy today... Breaking Bricks - Martial Arts
As I do every day, in one form or another.
Particularly thinking about simple Kinetic Energy, and then thought I'd write it out, and put it here to see if it's sensible, and for welcome input.
Ok, we've seen martial artists break bricks (and things). They might suggest various things surrounding the concept of chi, or ki, and some maybe be fraudsters*, but I know that if I punch something, it hurts, and there are in fact people that can put an incredible amount of force into hard things, and not destroy their hands as might be expected.
K, so the thought is that they really want to break the brick. If they fail, and the brick remains solid, then all of the "action" that they are putting into the brick will "react" upon their hand.
If, however, they produce enough force so that at the very moment of contact with the material, it breaks, (I don't know what you'd call the force required to fracture a brick, something along the lines of coefficients of friction, but I know that's not it), then once the initial breakage happens, then the martial artist is no longer up against the solid brick, but is instead simply pushing pieces of brick out of the way. Thus, the "reaction" to the hand is minimized, and the Momentum of the punch is simply released as that of the attack's follow-through.
So, it seems that the trick is to IMMEDIATELY break the brick. And if you don't believe that you can do it, then you'd better not, because you simply have to be committed to breaking it.
As an aside, I'd guess that this might be more along the lines of where chi would come in, because Chi is more about how the martial artist is dealing with his own internal workings. For example, in order to break a brick, you need a very rapid shock, and not a slowly-released impulse. The martial artist has to have that focus (and training) so that his or her hand is a metal hammer, not a sponge. So, the martial artist is typically using chi, or ki, or whatever their cultural equivalent, to give them the focus such that the maximum amount of energy is transferred from their fist to the target in a powerful burst, which I suggest might revolve around the practitioner's more highly developed control of their muscular and nervous systems.
* Even credible martial artists use some tricks, like putting bricks on spacers so that they're not trying to break through an effectively (almost) single giant mass of stuff.
|Wednesday, May 18th, 2011|
Can someone explain this...
I was playing around with a little rf detector today and I noticed something strange (the device is supposed to pick up rf frequencies in the 1MHz to 6.5GHz range). When I placed the antenna on certain parts of my skull it would go crazy beeping and flashing. I tried placing the end of the antenna in my mouth to see what would happen. As soon as I closed my mouth it beeped and flashed and then stopped immediately when I opened my mouth. I tested this many times with the same results. Not being a physics person, I was hoping someone could tell me whats going on here. I certainly dont think my head should be transmitting an rf signal, and if it is just that I am acting as a big antenna, then why does the device not behave identically when I touch it to my hand or my knee? Any thoughts?
here is a video of it
|Thursday, April 28th, 2011|
It is known that shinning a UV light onto green plants will make the plants fluoresce in the red and blue-green range (You can use this ratio to tell how healthy a plant is). The sun also emits UV light and thus the trees must be fluorescing all day. My guess is that we can't observer the fluoresce with our eye because the light it too weak. But could we pick it up on a spectrometer?
|Friday, April 15th, 2011|