Detection Definition and 324 Threads

I read in a couple of papers about asteroid hunting that they used artificially implemented asteroids in real images to see if their detection algorithms could find them. This way, the scientists determined their asteroid survey efficiency in real data. As I don't have the resources to work so...

Hi! I was reading this article about the possibility of detecting removals of "double-use" fissile materials from a known reactor using an antineutrino detector deployed in a truck "that uses 20 tons or less of scintillator material (and) could be fit into a 6-meter shipping container and parked...

Hello, I am using accelerometer to detect orientation change.for an e.g.if mobile accelerometer senses the direction that is it in portrait or landscape mode.so basically in this method the change of axis is detected . I am using the BMA250e module as an acceleromter,which has an inbuilt...

Dissolve a salt containingCr2O72- and an "inert cation" in water, would the following equilibrium occur in appreciable quantity? Cr2O72-+OH-⇔2CrO42-+H+ If it does occur, I suppose the acidity of the water would affect the equilibrium constant (or at least the relative concentration of the...

Hi, I'm really curious about this one. :) Let's imagine a massive, large object with a very low albedo traveling at a slightly sub-c speed enters the solar system and passes through it before leaving on the opposite side. Please, would us earthlings detect it as it approaches, passes by and...

I already done an experiment for detecting the presence of heavy metals(copper and lead) . The last step for detection is through the absorption of analyte by atomic absorption spectroscopy. Before that step to be done, the first process is to digest the water sample in the fume chamber...

I need to indentify this type of sensor. Need to work in dark. Need to scan only in x axis. ( not to have angle in y-axis only in x ) Something like a plate. And needs to react when movement is changed in that plate.

If I wanted to prove that some method is capable of destroying cancer cells, what would be the simplest way of going about this. Would it be sufficient to take a tissue sample containing cancer cells, and apply the procedure on it? How would you detect the existence of cancer cells before and...

There is a rumor going around that a gravitational wave inspiral has been seen at advanced LIGO. The web sites say it went on line in Sept, 2015, so I guess this is possible. Has anyone here heard anything?

This paper;http://arxiv.org/abs/1510.01733, Detecting Direct Collapse Black Holes: making the case for CR7, announce potential detection of a direct collapse black hole. Such a detection would shed light on questions such as the origins of SMBH and galaxies in the early universe.

Homework Statement Suppose teo particles with masses m1 and m2 enter a detector both with momentum p. Calculate the difference Δt of the times they need to cross a distance L. Suppose Δt can be measured with a 300 ps resolution. How long must L be if we want to distinguish particles with m1...

How can I detect shapes in an image using an algorithm? I have heard of using edge detection and from there the shapes can be identified, but how? Also, edge detection only is effective if the shape has a high difference of contrast from its surrounding area, what would be an effective technique...

Homework Statement Determine if two circular objects (both moving or one stationary), collide and if so, determine their final velocity. The two objects are being rendered using Graphics's Java library class, updating their position 60 times per second. Their position (x,y) is determined based...

I apologize if this has been already asked , but I'm curious about how scientists first found out that such particles exist? Since they are equal in all other aspects except for charge , well my best guess would be that in the large hadron collidor and other particle accelerators they have mass...

Hello everyone! I am trying to write an app that needs to be able to tell if a vehicle is accelerating or breaking. In this sense I used the accelerometer in the phone. At the moment I managed to isolate and subtract the gravitational pull of the Earth from my readings and I am using a noise...

I would like to find a computer program that will calculate the detection probabilities for particles in simple problems. For example, the user might specify that there are three detectors and two particle sources. We specify the complex amplitude of the wave FROM each source TO each detector...

Hi guys~ I have a question about lock-in detection method that commonly used in optical spectroscopy experiments, for example, the optical pump-probe reflectivity exeperiments on some semiconductor surfaces, or kinda like that. Usually, the sinario is: you use laser pulses, divided as pump and...

I am working my final year project on realtime qrs detection using pan tompkins algorithm, using matlab, i am facing problems in the thresholding part.needed help in this part. Thanks :)

Hello, I am wondering where a good article may be discussing the theory behind DC arc fault detection for PV systems. Seems most articles are based on detection for AC circuits. Trying to have a better understanding for troubleshooting purposes.

As I understand it, there is a certain probability associated with detecting spin states. Which if the spin state is unknown prior to testing is 0.5. But if I prepare an electron with say spin up, then measure it again for spin up I will detected spin up 100% of the time. Also, if I prepare...

I'm working on a project for a bottling plant that is trying to make a vision-based machine to detect cracked glass bottles before they attempt to fill them. It seems that the vision & backlight approach is the standard way to do this in the industry, but the shape of the bottle in this...

Assume a 2D problem. Given a linear antenna array, let's say 3 antennas distributed around the z axis, how could we extract the incidence angle of the received wave? Having 3 antennas equally spaced by λ/2 in the z axis and connected to each other, the result gain would be a function of ϑ (angle...

Homework Statement I am trying to understand how to obtain the estimated detection rate of a WIMP of mass 100~GeV into a Germanium detector of 1kg and detection efficiency of P_{eff}=70 \% . Homework Equations If you have at hand that the cross section is given \sigma = \mu_R G_F^2 (I...

Hi all, there is a facial detection program called eigenfaces that supposedly uses eigenvectors to recognise faces, can anyone here share any intuition on how that works or send a link? Any help apreciated.

This paper, http://arxiv.org/abs/1501.00996, proposes using atomic clocks for gravitational wave detection. It sounds similar to other ideas involving pulsar timing experiments. The twist here is utilizing satellites to provide a wide base for improved sensitivity. Sounds like an inexpensive...

Hi, I am designing a PCB with multiple 2-pos DF13 connectors in it (Like 50+). at the end of the board there is a 10 pos. cable. My intent is that the user (me) connects up to 9 channels in any position I like (I have 50 possible choices). However, this board is connected to another PCB that...

I have been reading on wikipedia that dark matter is made up of a not yet characterised type of sub atomic particle. Now we know that particle energies and relative positions cannot be known with precision by Heisenberg principle but we can calculate quantities like the drift velocity of charges...

This is the thread where we discuss some real and some obviously fictional scenarios (hostile spacecraft , missiles, or asteroids in either near-earth, cislunar or interplanetary space) with real world physics only. Specifically, things are detected by optics, radar-system and so on, things...

Hi everyone, I want to write a program in FORTRAN which calculate the detection efficiency for a punctual source and a disc source at a distance from the detector .The disc detector is assumed to be perfect: ie photon absorbing everything that falls on it. So here I am working in 3D and I use...

This thread is meant to explain and discuss why stealth technology does not work in space on the whole, as it does underwater or in Earth like atmosphere via various methods. It will also debunk claims by scifi shows such as that 'powering down' will make you appear as drifting space junk in a...

Hi, I have been reading about gravitational waves for the last few days. I saw any cylindrically or spherically symmetric body can not produce gravitational wave, can you please explain to me why ? I also need a brief explanation on why GW are actually produced. regards

1. A 2.5m aperture telescope obverses a star through an R filter. Assume that there is no noise associated with the detection system. The CCD has a full well depth of 20,000 counts and a gain correction factor of 1.00000. a. On average, the telescope detects 3 photons/sec from this star. What...

Since plants contain proteins that help them identify gravity in order to grow the right way, and they also contain phytochromes that recongize photons, could a possible relationship between phytochromes and the gravity receptors within plants indicate that the gravity sensors are actually...

Hi everyone, As you might gather from my moniker, I am a writer. I'm working on a sort of crime novel and have a weird question for you. I have a character who wants to kill another character using a particle detector. I have a couple ideas already but need one using a solid-state semiconductor...

In double slit experiments detection of individual electron has very massive effect on the result. Now suppose in dark room we perform double slit experiments with two observers (who cannot communicate with each other). Now those two observers have eyesight that can see individual electron in...

These papers, http://arxiv.org/abs/1402.4119 and http://arxiv.org/abs/1402.2301, make a case for direct detection of dark matter. The evidence takes the form of an unidentified emission line in the x ray spectrum of galactic clusters. The line is at a frequency and intensity consistent with...

Can someone recommend (if possible) a way to detect the amount of helium in a given enclosed space? I'm designing an experiment in which I will need to measure the amount in an otherwise vacuum.

According to phys.org: This is very unclear to me. How would one coarsen a reference angle? It seems to me it would be very difficult to set an angle without being able to check it later to determine exactly what angle you ended up setting. On the other hand, coarsening the detection...

". . . a coherent state remains unchanged by the detection (or annihilation) of field excitation or, say, a particle." — Wikipedia's entry on "Coherent States" I do not understand this. Is it saying that if a system in a coherent state, like a quantum harmonic oscillator, emits a...

This paper, http://arxiv.org/abs/1312.5320, discusses the possible detection of galaxies almost entirely consisting of pop III stars.

Homework Statement A one-dimensional infinite well of length 200 pm contains an electron in its third excited state. We position an electron-detector probe of width 50 pm so that it is centered within the well. (a) What is the probability of detection by the probe? (b) If we insert the probe...

I'm trying to figure out the theory behind a simple plagiarism detection algorithm I'm making. The essence is that it's a function f:S×S→[0, 1] where S is the set of all strings and [0, 1] is the plagiarism quotient with 0 being no plagiarism and 1 being a completely copied string (that...

Sorry - a very vague question: Could a superconductor be used to detect dark matter? The dark matter might interact with electrons in the superconductor giving them some momentum. These moving electrons would constitute a supercurrent which could be measured - maybe! Perhaps the...

Hi, Can someone please give me an insight as to what the latest techniques used to measure the cavitation on blades of pumps/turbines are? Are the any radio-isotope spectral methods to detect erosion/pitting? is sonoluminescence even observed in high speed machinery? Any other methods/...

Hello, I am designing electronic circuit board, and i want to only detect that the utility voltage is on. I don't want to measure the rms value of the voltage, only i wan to make voltage detection. The voltage range should be from 50VAC to 250VAC. I am looking for a cheap, small size...

Hi all, I have simulated (both in software and experimentally) inter-turn winding short-circuit fault in a single-phase transformer (working as a stand alone unit). I have the following observation but don't know the reason behind it:- The fundamental component in the no-load current is...

Homework Statement From Mathematical Statistics and Data Analysis 3ed, Rice 1.8 #61 Suppose chips are tested and the probability they are detected if defective is 0.95, and the probability they are declared sound if they are sound is 0.97. If 0.005 of the chips are faulty. What is the...

So in my lab, I am working with fluorescent bacteria, specifically GFPa1 (green fluorescent protein a1) which are excited with around 500nm light and emit around 516 nm. Forgive me if these aren't correct, it isn't essential for this write-up and my notes aren't in front of me. Is there any way...

hi all, i have done research and know the basic ones but could you guys please list all the methods of particle detection (especialy ones that detect neutrinos) that you know of I am learning particle physics and this would really help me.

please help i have to write a MATLAB code for DETECTION OF THE LOCATION AND SIZE OF A CRACK IN STEPPED CANTILEVER BEAMS BASED ON MEASUREMENTS OF NATURAL FREQUENCIES the reference paper is DETECTION OF THE LOCATION AND SIZE OF A CRACK IN STEPPED CANTILEVER BEAMS BASED ON MEASUREMENTS OF...