Identification Definition and 92 Threads

I was capturing an area of the sky using my Seestar S50, and there is something in the picture that I cannot explain. The capture has been going to about 40 minutes, and during that entire time it has moved around 3mm on my screen (and it is still going). I've looked at Stellarium, and looked...

Hi, as in this thread Newton Galilean spacetime as fiber bundle I'd like to clarify some point about tangent bundle for an Affine space. As said there, I believe the tangent space ##T_pE## at every point ##p## on the affine space manifold ##E## is canonically/naturally identified with the...

Hello, as the title says, how do you treat singly occupied orbitals in radical molecules, when trying to identify the HOMO and LUMOs? In the majority of cases I stumbled upon, like O2, both the antibonding orbitals, pi*2px pi*2py, are singly occupied, so they would be considered the HOMO, with...

Is it possible to identify a volume of space, observationally/statistically, that represents the 85:15 % ratio of dark matter and matter?

Hi, I have a high school student who supposedly synthesized a large quantity of Rochelle salt. I was looking for a conclusive chemical test to verify that it was indeed produced. This isn't because I actually suspect anything weird in the student project, its only for educational purposes...

https://www.vox.com/down-to-earth/22800793/mushroom-plant-poison-facebook-help-dog-pet

I have the following probability density function: $$f(x) =...

I thought it maybe could've been a snake skull when I found it, but upon further examination I could tell that it was in fact, not a snake skull, but more like a hardened, bone heart..? Hah. I'm stumped! Any guesses?!

Summary: I need to Identify my linear model matrix using least squares . The aim is to approach an overdetermined system Matrix [A] by knowing pairs of [x] and [y] input data in the complex space. I need to do a linear model identification using least squared method. My model to identify is a...

Every day the Earth is bombarded with meteors both large and small, most disintegrating in the atmosphere. A few strike the surface. Mars has no significant atmosphere. Thus, how is the marsquake signal detected by the InSight Lander distinguished from a true marsquake versus a meteor impact...

Hello, Could I please get assistance with a rock identification. I came across this one in the southwest part of the U.S. While I see a lot of slag from old mines, this rock appears to be something different than slag. Besides, it was the only dark colored rock I came across that day. It also...

Hello, Thanks for providing a forum where people can share their education/passion and help others. Speaking of helping out, could I please get some feedback on this rock I came across in the southwestern part of the U.S.? I picked it up because it didn't match anything else in the area. It sat...

Yesterday as I was hiking with my friend, I found a weird rock: My guess is that it is magnetite, since the mountain I found it has the biggest magnetite deposit in Taiwan.But I am not sure.It sticks to neoindium magnets really well. Close up: Is it something else,or it is magnetite as I thought?

Homework Statement What is the reaction occurring in H2O + SO3 -> H2SO4 2. The attempt at a solution Sorry, if this is dumb, I was confused about this question because I think its synthesis but I thought it only worked with elements? (Element A + Element B = Compound AB) But then with this, I...

I have not formally studied physics but am interested in quantum physics. I have studied calculus so I know a little bit about mathematics in case the answer requires it. My question is, when a physicist conducts experiments at the quantum level, how do they know that what they are "seeing" is...

From post: https://www.physicsforums.com/threads/random-thoughts-part-6.875108/page-180#post-5978198 I can see there is a gray-black stuff, but inside the gray-black stuff is a shiny lit moving stuff that moves in like a frenzy. What is the shiny lit moving stuff that moves across the...

In my x-ray crystallography data for a single crystal of NaCl using x-rays generated by Cu k alpha (154 pm), there are three peaks identified at angles of 14.155, 31.475 and 53.5 degrees. According to http://www.nada.kth.se/~fabo02/solid/xray.pdf, these peaks must correspond to only even values...

Hello! There are several methods to identify 'things'. For example, you can use magnetic field and its distortions will identify 'things'. Or you can use infrared light. Can you tell me please all the available methods? I am sorry I cannot word this better. Thanks!

http://www.scienceforums.net/topic/112257-help-me-identify-a-bacteria/its catalase +, oxidase +, ferments glucose and produces gas from the process, and is a gram + facultative anaerobe and its highly resistant to antibiotics and motile + and has been seen to grow up to temps of 103°F, colonies...

Homework Statement Fill-in with the correct tank letter or the condition (eg. PPM of O2) Refer to above Chart A: __1. Which tank contained the lowest PPM of Oxygen? __2. Which of the 4 abiotic conditions(02, C02, PH, or Temperature) is most out of line in tank...A-G? __3. Which tank has a...

Lately I'm learning how to identify the most common rock-forming minerals, but I have some doubts about it. First of all, how can I distinguish between massive minerals and rocks? Second thing, a massive mineral from what I understood, has an internal order (so it's not amorphous), but that does...

Lagrangians that include a particle field and its corresponding antiparticle field always have the particle field and the antiparticle field in the same terms. For example, in the theory of a complex scalar boson ##\phi##, the Lagrangian is a function of ##\phi^{*}\phi##, and not of ##\phi##...

https://drive.google.com/file/d/0B39n6QfDU8f3SE9nUHhHckRIRFE/view?usp=sharing https://drive.google.com/file/d/0B39n6QfDU8f3SE9nUHhHckRIRFE/view?usp=sharing 1. Homework Statement I am not sure about the concept of zero-forced members. There are forces applied on the members, why are they...

Today's xkcd: http://meteorites.wustl.edu/check-list.htm']Meteorite[/PLAIN] Identification [Source: http://www.xkcd.com/1723/] Clicking on the image gives you a link to an actual flowchart: Self-Test Check-List {image does not support hot-linking, so I removed direct link to flowchart...

The numbers seem to read 225 PC 330 4 What does it mean? Someone told me "225 = 22 x 10^5 pF = 2.2 μF" with 330 V being the potential rating "PC" = polymer cap Is this correct?

While visiting Wyoming recently I was shown a "rock" that several people have said is a meteorite. My question is how does one identify a meteorite compared to an Earth rock. (Hoping you can help me out here Dave) I have included several photos and I can say it definitely shows signs of high...

This is a fast-question/need of confirmation concerning the two: Reconstruction and Identification. I am trying to "separate" what they mean. For example when we reconstruct a jet, we apply several selection criteria that the object "jet" should satisfy. Is that correct? Then any object that...

So I recently did a titration lab with a monoprotic acid and sodium hydroxide. After using stochiometric ratios I found the molar mass to be around 175g/mol. It is possible I have a huge percentage error, but can anyone think of an acid that is monoprotic and is within the range of that molar...

Hi all, I have 40 signals recorded on a vehicle. Some signals are analog and some are digital with 4 different states. One signal (I call it A) is really important to me, it is positive and all the other signals lead to its variability. For example, when there is a state change in a couple of...

Homework Statement I need to find the X of two substances using only the data found in lab. Which is: nmixture=1.4156 nbutan-2-one=1.3787 ntoluene=1.4970 For the mixture, I don't know what X (the mole fraction) is. That is what I must find out. Homework Equations nmixture= (Xbutan-2-one...

I've been riding my bike in the park and I've noticed this guy passing by. It was of a hand palm size. Intriguing. Can you help me identify the insect?

Homework Statement For the identification of β-naphthol using dye test, it is necessary to use 1. dichloromethane solution of β-naphthol 2. acidic solution of β-naphthol. 3. neutral solution of β-naphthol. 4. alkaline solution of β-naphthol. Homework Equations NA The Attempt at a Solution...

Dear all, I have more than 1500 matrices that are the occurency frequency of a bivariate dataset, something like the following: [0.1, 0.3,0.1;0.4,0.05,0.05]. I need to extract the few of them that are really different from the others. Instead of visually analyze each of them and trying to...

I have some questions concerning this paper (mainly about the tau identification): http://arxiv.org/pdf/1201.5466v1.pdf especially the figures 3-6... I don't understand what is the inverse background efficiency, neither the likelihood score. As a result, I am unable to understand what info the...

Reader, Forgive me if I break any of forum rules, as I am a newbie posting here. Today, last minute Christmas with my beloved other, I found some sort of vintage electrical device. I understand the basic principles behind what would be happening on the stand with electricity. However I am...

Homework Statement I am trying to establish the the dynamics of an inverted pendulum for further analysis. I understand that this is a well known problem, but the governing equations in various sources are different and make it difficult to keep track of what forces are being applied on the...

Hello all. I am not an electrical expert here, just know enough to wire basic things at home (i.e. switches, outlets, etc)...so please be kind. My situation is this. We recently bought a new house and have found a couple of mysteries. The biggest one is that there are several electrical...

I am a little confused about exercise 1.2 in the book "Quantum Computation And Quantum Information" By Michael Nielson. The question is: Explain how a device which, upon input of one of two non-orthogonal quantum states |a> or |b> correctly identified the state, could be used to build a device...

I am in the process of reverse engineering an electrical control box for a spa heater, and have stumbled upon a component that I have not encountered before. There are two of these components in the system. I was not able to find any information from the part numbers. The coil leads me to...

I have been struggling with one simple question. How can one measure the momentum of a particle within a field without disrupting the entire field, all together? If the particle is under observation at at t_0, how is it verifiable that at t_1 the same particle is being observed? Obviously spin...

Hello guys, i have saturated spectrum of Rb. My goal is to identify which lines i see. http://imagizer.imageshack.us/a/img835/8787/xvwr.png So from http://www.opticsinfobase.org/oe/fulltext.cfm?uri=oe-15-10-6293 I have identified that there are to 2 Isotopes: Rb85 and Rb85, further from...

Hi, physicsforums! I have a dilemma: there seems to be several strange instruments in our class that nobody is able to identify. The description is as follows: One strip is a brown metal (copper?) and the other is a grey metal (invar? iron?). (I'm making guesses at the metals due to the...

Homework Statement I am working on an experiment rite up for a physical chem class regarding the n-Hexane/Acetone azetrope. I have done my calcs, tripple checked both the data and the clacs and everything is as correct as it can be at this point (i can't change figures recorded in the lab...

Homework Statement Anand, Bhadkamkar, and Moghe (1995) used a fractional factorial design to determine which of the six possible factors influenced the determination of manganese in cast iron. The six factors and their levels follow: A-Titration speed ; Medium...

I'm endeavoring to prototype a challenging sorting mechanism inside a fridge and would appreciate any tips on how to get from the specs to a plausible design. #Problem The aim of the game is to identify and sort food items in the limited space of a fridge - such that a user would push...

Hi all, Perhaps I'm asking the wrong question but I am wondering about the relationship between different definitions of, for the sake of argument, the torus. We can define it parametrically (or as a single constraint) and from there work out the induced metric as with any surface. But...

Can anyone identify what kind of knot this is, if it is one? I'm not very familiar with knot theory, so I don't know how I would go about "identifying" the knot. Any help is greatly appreciated. Thank you.

Attached is a picture of a component i am trying to identify. I assume it is either a piezoelectric sensor or a wheatstone bridge, But i don't know which one?

I have an unidentified radiation source. I used a NaI(Tl) detector and multichannel analyzer to collect data and plotted the spectrum. I found peaks at energies of 86.3, 123.7, and 369.6 keV. From this data I am attempting to identify the source, but I am having a difficult time. I tried using...