Detection Definition and 339 Threads

Hi, I'm trying to design a system which will be able to detect a hot object on a cold surface. The downside is the temperature difference is only 1 degree celcius and I'd like to use IR from a distance of about 10cm (further away preferred if possible). Does anyone with any experience of...

Hi, I'm not a physicist although I've studied it to first year degree level in the UK many many years ago. I was just reading an article today on the BBC about a new image that's been captured of the visible universe. The following quote got me thinking and I wondered if your expert knowledge...

Hi. I am using a 3 axis accelerometer for motion detection. I can easily determine the tilt using simple triginometry but cannot determine the movement in a particular direction. For example the sensor is at 45 degrees to the floor so the x,z coordinates are x = 0.5, z = 0.5. So if I keep the...

Hi I'm studying decay of atomic nucleus. Alpha and beta rays are essentially particles and their path are easily traced. But high frequency gamma rays easily penetrate metal foils, and I wonder that how gamma rays are practically detected and measured in lab experiments? Is photo-electric...

My understanding of how interferometers work is that they detect gravitational waves because they alter the distance between two mirrors as they pass through. They do this by using the wavelength of a laser beam passing through this space. However, shouldn't this always fail to detect anything...

my view. The current theory of the higgs field is based on the higgs boson. Now a boson, in theory has to conform to the rules of super-fluidity or a Bose-Einstein Cond. I can confer because of this, All higgs bosons, would be interlocked as a field acting as one particle. I can say that since...

So my mind tends to wander, but I was thinking... since active/passive sonar is used to detect objects underwater, couldn't thermal imaging be used as well (in conjunction)? Isn't there any reason why we couldn't combine the two sensors into cooperatively working together to detect submarines...

For this question I am considering a slit diffraction experiment set up as follows: {Monochromatic source} ------> {Single slit} ------> {Diffraction grating with N slits} ------> {Screen with small movable detector} The monochromatic light source emits photons one at a time. The principal...

I'm doing signal processing using MATLAB. But facing problem when doing Peak Detection. This is the signal that I used for the processing: This is what i wish to do: a) the horizontal line is the threshold point and b) the circle is the peak detection Can anyone help me...

As part of an engineering design project, I am using shock switches to measure accelerations of an object. As the name suggests they are just switches that turn on when a shock above a certain value is experienced. Does anyone know the details about how the switch contact is closed when it...

I am designing a system that must automatically detect if a person is inside their office. The trick here now is that there are people going in and out and i just want to detect the owner of the office. Tracking them is useless since the average office sizes are not big, 5m width maximum so my...

Hey everyone! I programmed a verlet physics engine that works great. I got to the collision detection and response and it's been frustrating to say the least. I've tried tons of different ways, but no cigar. The collisions themselves are between points and lines between points. These...

Hi, I've got a problem with collision detection of which I am struggling to find a solution. In the simplest case, I would have a sphere whose movement would be constrained inside a closed arbitrarily-shaped object. I have been looking into BSP trees which split the shape into chunks...

What is the state-of-the-art of detecting gravity waves. Are the instruments available now sufficiently sensitive to detect gravity waves? Have we identified 'low-hanging' sources from which gravity waves should have been detectable. Have we yet reached the point where doubts are arising as to...

What is the state-of-the-art of detecting gravity waves. Are the instruments available now sufficiently sensitive to detect gravity waves? Have we identified 'low-hanging' sources from whom gravity waves should have been detectable. Have we yet reached that point where serious questions are...

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...

Hi I have a problem in detecting whether string is vibrating or not. I'm going to conduct experiment which will investigate impact of different factors on time of decaying of guitar's string oscillations but I have no idea how to measure when oscillations stopped. Acoustic method doesn't work...

In another thread, which I do not want to derail, I claimed that a free, non-interacting particle is not physical and that it cannot be detected or observed. It was pointed out to me that apparently I'm the only one on here who doubts about the possibility of detecting a non-interacting...

Sorry if this question has been reproduced elsewhere. If the universe expands greater than the speed of light, c, will a light ray from a distant object never reach us? Lawrence Krauss gave a nice presentation and commented about this, but this has thrown my nose out of sorts because I think...

Hi, Just a query... what is the differences between this types of detection and their usage? a) heterodyne b) differential c) normal d) homodyne?

Hey Everyone, The title of this thread may be a bit ambiguous but what I am wondering is if there is a way to determine if a MOSFET in an output stage has shorted. The scenario I want to catch is the case where the FET drain is exposed to too much voltage (from a collapsing spike or some...

What do you guys think would be the best way to trip a camera so that it goes off only for when a train is passing through it? Sorry I can't get anymore specific than that. I was thinking laser tripping device but was wondering if there is anything out there that maybe used that ya'll might...

Hey ppl i wanted to know that wat is the name of the method with which astrosphysicists are able to detect the elements present in supernovae.for eg they say type 2 suprnva is mainly hydrogen containing. Is it by spectroscopy if yes which one? pleasez temme soon

If you have 2 laser beams, A and B, at right angle with each other, that you send towards a beamsplitter (BS), such that you get 2 output beams from the BS, one being the sum of the reflected part of A and transmitted part of B, and the other the transmitted part of A and reflected part of B...

I want to be able to differentiate between longitudinal(P) and Shear(S) waves in solids. Using one Acoustic emission (AE) senor placed 2 to 20 cm form a AE source e.g. a stress induced crack or pencil lead test, how can one detect both the P and S waves and determine what part of the receive...

Dear all, The idea is to detect break down of a group of blades inside a pipe. It’s very difficult to install any type of sensors inside a pipe without having them damaged, given that the pipe is an air vacuum suction system. How about concentrating on the physical properties of the blade...

We have a surface that is 10 cm x 10 cm. That surface is uniformly covered with a radioactive material. When radioactive material decays, it has a equal probability of emitting radioactive particles, in this case beta particles, in any direction (360 degrees). We have a detector that...

Hi, I am working on a simulation code that simulates the deformation of sand grains in 2D. The sand grains are modeled as simple polygons. However, during the simulation the grains can deform to create non-convex vertices. Further more, when deformation becomes extreme, there is a possibility...

Hi to everyone: Does anybody of you know when was the gluon detected?, and how do you detect gluons? I hope you can answer Thank you

It is known that with the formula that accounts for the time dilation effect in hand we can derive directly the formula that accounts for the length contraction effect: L0/Dt=L/(Dt)0 (1) where L0 and (Dt)0 are proper length and proper time intervals, L and Dt...

I am to design a sensor element that can detect a leakage through a thin metal disc (rupture disc) in a pipeline. Ideally, the metal disc closes the pipeline at the upstreaming side with certain pressure. Its downstream can be either open to atmosphere or close. When a higher pressure occurs...

I am having difficulty understanding why the single rate of detection (as opposed to the coincidence rate) is unaffected during Quantum Eraser experiments. I'm looking at the great Kwait, Steinberg and Chiao paper: 'Observation of a "quantum eraser": A revival of coherence in a two-photon...

So I posted this in a few other forums, but I thought that this would be a good place to get even more feedback. Sorry, mods. Does anyone here know what developments are being made in nuclear detection technology? Is there anything like, say, an airborne sensor that can detect the tiniest...

I am just "trying" to watch interstellar TV... The detection range in lightyears is R = \sqrt{\frac{\text{EIRP}\cdot A_{e}_{r}\cdot\text{twc}}{4\pi\cdot\text{SNR}\cdot B_{r}\cdot k_{B}\cdot T_{sys}}}\cdot\frac{1\,\text{ly}}{9454254955488000\,\text{m}}, where \text{EIRP} = P_{t}G_{t}...

can some one give me a link or an article or his argument which Explain how the Bethe-Bloch formula is used to determine the energy of a gamma-ray photon stopped in a spark-chamber detector. thanks

How to improve sensivity of detection circuit(Photodiode)??

does anyone know the chemical process involved with these? pretty much a white sticker and when it gets wet it turns red.

[SOLVED] Momentum-space detection of an Electron (EWP) I know there have been plenty of questions about electrons, momentum, and wave packets recently - but my question is distinct (and comes with a picture!). Question: If you ionize an atom and detect the resulting free electron wave packet...

In the book 'Quantum Physics', Alastair Rae uses polarized photons and photon detectors to describe many effects observed in quantum physics. In his typical setup, photons are passed through a polarizer and exit it through two different channels depending on the polarization \phi or...

Hello. I'm having the hardest time finding a product (preferably an IC) that can detect shock. Like if you dropped your phone on the ground it would detect an impact with the floor, with some kind of threshold to ignore minor bumps and thumps. I did find some toshiba ICs called "shock detector...

They say Higgs particles are so hard to detect because their mass is so big. But when their mass is so big, wouldn't that make them easier to detect?

Hi Ho! Is there a better way of looking at more than one threads of execution besides enumerating all of the possible paths so that a person can quickly determine whether there will be a problem or not? When I face a question of determining whether two threads of execution will have a...

hi all, I am testing the collision detection between two circle using classic the distance < sumRadius. now i need help to detect the penetration of circles and to resolve the penetration before collision reaction

Hi there I'm looking for anyone who has the knowledge or experience that can help me develop a pulse induction gold metal detector. I have the fabrication resources but need someone who understand metal detection/circuit board technology. Please Email with experience.

Question Details: The following blocks have been encoded using the two-dimensional parity error detection scheme. That is, the rows have been encoded using odd parity and the last row holds the parity bits of the columns which have also been encoded using odd parity. There are two possible...

The Higgs boson introduced by P. Higgs (insert --> the spontaneous symmetry breaking with the gauge theories was also constructed by Robert Brout & Francois Englert) one question I do have is on the dynamics involved dealing with this concept - is it truly possible to detect the process by decay...

An interesting review paper of the search for DM particle(s): Direct Detection of Cold Dark Matter. The search continues. Garth

Hi guyz my teacher recently asked me..how did we actually discover(or how do we find ) a neutrino particle...remember a neutrino particle has 0 mass and 0 charge.. well my guess to this was using rest mass theory...which says tat..some particles wen givin velocity above the speed of...

Greetings all, I thought I'd post my idea and plan for my digital electronics project here to see if I can get any tips or meet people who may have some expertise on this subject... The basic idea is a 'lock' that is opened by the correct series of input notes. Using a PIC, what I'm...

Hello everyone. I am looking for a practical method to detect very small currents in nano or pico amperes. Are there galvanotmeters or devices capable of doing that? Thanks a lot.