Questions tagged [data-analysis]

Use for question relating the the techniques of data analysis.

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811 views

Moment of Inertia and Mass Experiement

I am currently working on a physics project to experimentally confirm the relationship between mass and moment of inertia. The experiment is setup as depicted: In this experiment, $r1$ and $r2$ are ...
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1answer
89 views

Difference between Fourier and Laplace transforms in analyzing data

I have a set of displacement-time graphs from an experiment to convert to the frequency domain. Both the Fourier and Laplace transform seem to do this, so what's the difference between them (...
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1answer
361 views

When to round off standard deviations in uncertainty propagation?

Let's take a concrete example. One is dealing with a wire through which a DC is running. One measures its voltage and obtain its current by measuring the magnetic field around it in some way such that ...
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1answer
141 views

Question when comparing two experimental results

In my textbook it says that if two experimental results vary less than 3$\sigma$ then they can be considered to have arrived at the same result. My question is how do you determine this "x$\sigma$". ...
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1answer
136 views

Data driven and MC simulated background in experimental particle physics

In experimental particle physics, we use for data analysis a set of samples to simulate the background and the signal we want to observe. When reading articles, I often encounter a section dedicated ...
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1answer
239 views

Comparison between Bethe-Weizsäcker-Model for the nuclear binding energy and measurements

I tried to compare the binding energies of between the measured data and the Bethe-Weizsäcker model. My plot looks like this and I don't understand the large discrepancy: For the measurement I used ...
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1answer
397 views

Interpretation of invariant mass distribution plots

Can someone explain what exactly a invariant mass distribuition is and how to interpret the follwing graph. Especially what Events/GeV means.
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1answer
184 views

Finding the combined uncertainty of weighted measurements

I am currently doing some simple simulations of radiation dose from several treatment fields. I am looking at the dose within a certain voxel of a patient receiving radiation therapy, being treated ...
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1answer
137 views

What is the electron energy scale calibration?

I am reading a paper from ATLAS collaboration in CERN and it is mentioned the "electron energy scale calibration" many times. It must be related to energy calibration in the experiment but I would ...
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1answer
421 views

How to implement Hubbert's potential to calculate permeability using Darcy's law?

Question: How does one implement Hubbert's potential to calculate permeability without making assumptions to neglect any aspects of the potential defined by Hubbert? Question's supplemental material: ...
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1answer
349 views

Sloan Digital Sky Survey (SDSS) spec file headers

I downloaded spectra from Sloan Digital Sky Survey (SDSS), which has the following column headers flux, loglam, ivar, and_mask, or_mask, wdisp, sky and model (...
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1answer
105 views

What is the correct way to handle significant figures when calculating compound uncertainties? [duplicate]

When processing experimental data, and calculating an uncertainty value in multiple steps, should intermediary uncertainties be used to a certain number of significant figures or kept to the full ...
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1answer
193 views

Curve Fitting and Multiple Experiments

Say I do an an experiment 5 times, each of which gives you a list of data points. Do I fit a curve to each one separately and then average the parameters and their uncertainties? Or do I take the ...
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1answer
31 views

Choice of color for graphs with filled area [closed]

I am writing an article and the central results are summarized in a graph so I want it to be very beautiful and physically intuitive. It has 3 regions in which a certain quantity is conserved, ...
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1answer
2k views

gaussian fitting of xrd peaks

I am reading a paper regarding the nano crystalline material with hexagonal crystal structure. In that paper in order to find out lattice parameter of hexagonal crystal structure they have fitted a ...
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1answer
164 views

More points vs. precision

I have a dilemma. In my lab exercise, I was measuring spectra with HPGe detector of several sources (gamma spectroscopy). To determine the energy of the unknown spectrum I first needed to calibrate ...
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59 views

Is there an index of common spectral lineshapes or table of common lineshape functions?

Is there an index of common spectral lineshapes in physics? Is there a program that automatically tries fitting to many different lineshapes? By line shape I mean the function that, given ...
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48 views

What should be the real error band of a fit function?

This is a question concerning data analysis. It could relate to particle/nuclear physics or other field. Please note that this question has nothing to do with technical problems, and is more of a ...
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31 views

Uncertanty in Chi-squared measurements, spectra-like

Let's say I have some observational data. For example: in a certain wavelength interval I measure the flux, 10 000 points, and I have the uncertainty for each one of them. For example: ...
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38 views

Mathematical Resolution of Overlapping Signals

I would like to take the opinion of physicists (my area is chemistry). During instrumental analysis, the output is a instrument response vs. time. Each peak corresponds to a molecule which is ...
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62 views

Data-analysis (Uncertainty and errors)

This is just a data anlysis question but I thought you might need an introduction. In order to calibrate de Michelson interferometer one needs to find $\eta$ in the relation: $d = \eta D_\mu$ where $...
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1answer
35 views

File with particle decay data [closed]

Does anyone know of a computer parsable file that has basic physics and decay data for (quite many) observable particles, such as mesons, barions, heavy leptons and $W, Z, H$? To clarify the data I ...
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22 views

Does the vertex efficiency include track reconstruction efficiency?

Consider a document of ATLAS collaboration on displaced vertex level efficiency. On the first two pages there is a description of cut-offs required to background free displaced vertex reconstruction. ...
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1k views

Parallel Axis Theorem Experiment

I am currently working on a physics experiment to confirm the parallel axis theorem. To do this, I have the following setup: In this experiment I change the distance between the centre of the ...
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50 views

Can a particle be identified when one knows $\left<dE/dx\right>$ and the Cherenkov angle $\theta_c$?

I have a question about if it would be possible to identify a particle by measuring the energy loss due to ionization $\langle dE/dx\rangle$ and the Cherenkov angle $\theta_c$. I assume that we know ...
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2answers
63 views

How does finding the $y$-intercept of a graph reduce error compared to finding the average of the data set?

In my particular case I have the equation $$ \frac{1}{d_i} = -\frac{1}{d_o}+\frac{1}{f} $$ and I'm plotting $\frac{1}{d_i}$ against $\frac{1}{d_o}$ to give an intercept of (in theory) -1 and a $y$-...
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277 views

Determination of spring constant $k$ for an elastomer

Primary Question: How can you determine the spring constant $k$ of an elastic material? I was recently tasked with finding the spring constant for a series of elastomeric materials, the first of ...
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3answers
85 views

Describe the dynamics of a fluctuating vector

I have a time series for the $\mathbf{v}(t) = (x,y,z)$ components of a vector quantity. It is fluctuating in time, and has a non-trivial autocorrelation function which I want to somehow elucidate. The ...
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40 views

Is there a mathematical model that models spectral power distribution curves?

The experiment was aimed to find the specturm cruve of different light bulbs experimentally. Is there a mathematical way to justify the results I obtained (the plotted graph)? Would the equation in ...
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0answers
64 views

Interpretation of TGA-DSC data in terms of composition of iron oxides

I have thermogravimetric (TGA) and differential scanning calorimetry (DSA) data for an iron (hyd)oxide sample and I would like to interpret this data in terms of the composition of the starting ...
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57 views

Comparing measurements from Sound Level Meters and Audio Recorders

I've been working with an environmental sound recording system that consists of a microphone -> sound level meter (SLM) -> digital audio recorder. Recently I've been involved with implementing a ...
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1answer
93 views

How to take measurements for wavelength in an experimental wave tank?

To anyone familiar to the experimental hydrodynamics field, how does one experimentally measure the wavelength of the waves generated in a plunger type wave tank or any wavetank for that matter. From ...
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40 views

Where can I find CIE 1931 RGB matching functions?

I'm unable to find CIE 1931 RGB matching functions online. Where could I find them (ideally in a tabular form with 1 nm radiometric resolution)?
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69 views

Looking for raw spectral data in the time domain… so I can do my own FFT analysis on it

I'm trying to get the spectral data of the periodic table of elements in the time domain format or find a site that has the data in the time domain format. All the sites I know have the data in the ...
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288 views

Na-22 Branching Ratio

I tried to calculate the branching ratio for $^{22}Na$ from experimental data using a Germanium detector. My derivation is as follows: The formula for the branching ratio $BR$ for electron capture $...
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663 views

How to read Inverse Pole Figures (IPF) images

When (Electron BackScatter Diffraction) EBSD maps are procesed the output crystallographic orientation is derived into Euler map and three Inverse pole figures (IPF) maps. In the example there is IPF-...
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25 views

Data Analysis: Image Sharpening through Posterization

I had this image, a picture of Jupiter: I wanted to measure the pixel diameter of Jupiter. As evident, the image is quite blurry, and thus, many value of equally justified pixel diameters can be ...
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1answer
184 views

Normalizing temperature data of CPU sensors to ambient [closed]

My scenario: I want my application to stop or take some decision based on temperature. say like if my ambient is morethan 41 i want to switch off the application and we do not have an separate ...
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0answers
140 views

Sine wave in my residuals graph [closed]

We had a physics experiment where we should have had a linear relation between 2 measured values, we got a pretty good fir however our residuals plot has a kind of a sine wave behaviour. We were told ...
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22 views

Starter projects/visualizations/analyses? [closed]

I just renovated a desktop that had been in storage for a while and I am looking for good ideas for data analysis or numerical analysis projects in physics. I have taken up to E&M, and special ...
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1answer
47 views

Karhunen-Loeve transform of a repeating process

This question is inspired by measurements of an unsteady flow. I have some doubts about interpretation of principal component transform using Karhunen-Loeve theorem. I have (centered $\equiv$ zero ...
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49 views

Data Collection of oscillatory motion

I'd like to study nonlinear oscillatory motion this semester. I plan to build several different mechanical systems (pendula, masses on springs, etc with and without driving forces, large/ small drag, ...
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76 views

Manager for results of physical simulations [closed]

I have quite a general question. I'm phd student in the field of plasma physics, our team has developed a numerical simulation of a diagnostic method in plasma (langmuir probes), written in fortran. ...
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1answer
124 views

Looking for an Time Series Analysis Text [closed]

(Apologies, I could not think of a better title). Two days ago, I was in the Library at Köln (Those who know it, knows that the books are not ordered by subject - but by date of buying, and one has ...
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89 views

How to calculate the correct coordinates from a distorted video of a projectile?

I am working on a high school project that is related to projectile motion. I am exploring how exactly the position of the center of mass affects the trajectory of a long but thin, javelin-like ...
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111 views

Fitting of data to a model

Imagine that I have some observable value predicted with a theory for some process to be: $1+a x + b x^2$ and observed value is 1.3 with an error 0.2; a and b are some numerical constants. I also have ...
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2answers
344 views

Gamma spectroscopy - Do annihilation photons produce a backscatter peak?

Below is a diagram of part of a structure which I find in a gamma spectrum taken from a hall in which a neutron source is undergoing spallation. The structure which I'm interested in can be seen ...
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2answers
88 views

Big Data Handling at the LHC

My understanding is that much of the data that is is collected at the Large Hadron Collider is similar to that in the image below, and that a vast amount of the data contains little of specific and ...
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1answer
216 views

Can this type of graph be analysed to produce any meaningful data?

The above is a graph of pendulum length on the x-axis measured in metres, and pendulum period on the y axis measured in seconds. The pendulum period is not squared. If I square the pendulum period, I ...
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3answers
89 views

fit funtion to the Sun electron fluxes data

I'd like to fit a function to the Sun's electrons flux data (blue dots), please note that x,y axis are in the log scale. The green dots are the "best" fit from the gnuplot program. I have taken the a/...