Science topic

Question
Dear All,
I am doing demographic and health survey (DHS) cluster base analysis. I created buffers of 20k, 10km, 5km and 2km around the DHS clusters. Now i want to extract/calculate total number of cells/pixels fall in each buffer mentioned above. How i can do this in ArcGIS/ArcMap). I already use zonal statistics as table tool of arcgis but count in that table does not match across various buffers. For example count in 20km is 17 while count in 5 km is 250 which seems wrong logically.
you can do one thing create a fish net using Create Fishnet tool in Arcmap by specifying the pixel size while doing that, mark the "create the label point" option, which will give a point for each pixel. Then use intersect command mentioned in Geoprocessing to extract the fishnet for each study area. Here you can add a Serial number by editing labels in Properties. That will give a total pixel in your study area. I hope this method will help you
Thank you
Question
My theory has G (Newton's Gravitational Constant) to be inversely proportional to the 4D radius of the Lightspeed Expanding Hyperspherical Universe (LEHU topology).
I need to simulate the Stellar Population under the epoch-dependent G assumption.
At this time, I consider that there should be a seed stochastic distribution of t_{ff} (which is inversely proportional to G*rho(0)
That distribution would be used over and over again to seed new stars at different epochs.
My problem is simulating the aging of previously triggered stars. For that, I need a consumption rate that is dependent upon GM. As far as I can tell, all star's processes are dependent upon the product and not just on the mass.
I welcome guidance.
On the average, doubling the mass of a Main Sequence star increases its brightness by about a factor of 10, and reduces its Main Sequence lifetime by a factor of 5. For a rough but thorough discussion (intended for beginning college students), http://cseligman.com/text/stars/mldiagram.htm (The Mass-Luminosity Diagram and Main-Sequence Lifetimes) on my astronomy website.
Question
In general the strength of confinement of nanoparticles is defined by reduction in the size nanoparticles with Bohr Radius. But lot of paper discusses and compared crystallite sizes with Bohr radius. Actually which exactly correct. Kindly replay....
Dear PK Vasudevan,
It is more reasonable to calculate crystallite size when utilising XRD analysis rather than analysing particle size. This is due to the fact that a particle is made up of several crystallites or grains. So, the importance of crystallite size consideration is greater. The crystallite size should be on the order of the Bohr exciton radius in order to accomplish nanoconfinement. The distance between an electron and hole pair is known as the Bohr exciton radius. If this is accomplished, the substance is referred to as a quantum dot. I hope that this clarifies your query.
Question
In radio access network, as there are femto and pico cells inside the macro base station. How much the coverage area of macro base station is recommended by standards of 5G architecture?
There are situations where one can achieve the 45-60 km radius in rural areas.
However, the benefit of 5G isn't to provide better coverage but higher capacity within the coverage area. The capacity demands are high in urban areas where the inter site distance is only a few hundred meters. Neighboring base stations will then have overlapping coverage areas, so interference coordination is important.
Question
Im working on a robotics SWARM problem, and need to localized the robots using acoustic modems. Its a Source Localization Based on Time Difference of Arrival (TDoA) Measurements. I have found this approach Two New Shrinking-Circle Methods for Source Localization Based on TDoA Measurements . Here the link of the approach :
And they described the approach and mentioned its implementation in MatLab. The approach can be described in this steps
Step 1. Compute the maximum radius Rmax and minimum radius Rmin of r1.
Step 2. Compute Rmid, where Rmid = (Rmax + Rmin)/2.
Step 3. Calculate the solution X when r1 equals Rmid, and then calculate f(r1).
Step 4. Update the value of Rmax and Rmin. If f(r1) > 0, Rmin = Rmid; otherwise, Rmax = Rmid.
Step 5. Compare the value of |f(r1)| with a threshold TH1 and compare the value of |Rmax − Rmin| with a threshold TH2. If |f(r1)| < TH1 or |Rmax − Rmin| < TH2, terminate the procedure; otherwise, return to Step 2. When the procedure is finished, X is the coordinate of the target.
So please can help to find some possible solution implementation in Matlab or some help to point it out how can be done that in MatLab?
Thanks
Hello! You can save the results as figure Or you can save the data from the workspace and load them
Question
In textbooks on astronomy, we can find information that the radius of the habitable zone is influenced by the luminosity of the star, the sperctral class, and metallicity. But are there any formulas or equations, using which, knowing these parameters, you can find the radius of the habitable zone?
Question
I have designed two circular hollow waveguides in CST, one has a 1 mm radius and the other has 1.8 mm. i am plotting the phase constant (beta) vs frequency. I am confused about what this plot defines.
also, I get two different plots from the same design. 1 from the 2D results (s-parameters) and the other from the port information. (attached picture)
can anyone tell me whether these plots have the same meaning or relation? and what this plot defines. is it good or worse?
thanks
Your top plot looks reasonable, but I would expect it to be in radians per metre. It looks like you have taken the phase change over a given length and divided by the length, but forgotten that the phase change can only get up to 2pi before it drops to zero again. The same applies to the second figure. You need to either use a very short length so that the total phase change never exceeds 2pi or unwind the phase by adding 2pi more at every step - some software packages have a function that does this.
The third figure looks like what I would expect for modes with different cutoff frequencies (wavelengths) in waveguide, where 1/(cutoff wavelength)^2+1/guide wavelength)^2 = 1/free space wavelength)^2. The vertical value is 2pi/(guide wavelength)
Question
In Exofop website, not for every tess object of interest (TOIs) mass is given but parameters like radius, insolation orbital period is given? Is there any model or relation to get the mass
To obtain the mass of the planet, it is necessary to use radial velocity data. Radial velocity data are usually not available for all planets. Photometric data can also be used to estimate the mass of the planet using ellipsoidal variation and the Doppler beaming effect. You can see the extraction of the planet's mass from gravitational modulations in this work.
Question
why emulsions are always thermodynamically unstable? how to solve this problem
A water-in-oil emulsion is prepared by homogenising 5 cm3 of water into 10 cm3 of dodecane containing surfactant. The average radius of the droplets is 12 m. Calculate the total oil-water interfacial area generated in the emulsion in SI units. State any assumptions you make.
The statement that emulsions are always thermodynamically unstable is incorrect. Please read about the difference between unstable macroemulsions and stable microemulsions.
About your actual problem: I suppose this is an exercise to a lecture, right? Did your lecture say anything against simply calculating the area of a spherical droplet with the given radius and multiplying that with the number of droplets?
Question
is it possible to convert a nanosphere of radius 8 nm (each atom has 0 charge) from all-atom representation to coarse grain representation to run a simulation using GROMACS?
dr ibrahim, it's a difficult way and professional. The possibility of error in Gromex is high
Question
Dear All,
I need to put DNA inside the spherical wall (wall radius is 5nm) without any boundary conditions (PBC). Hence, DNA will be confined inside a spherical wall during simulation. Is there any way to achieve this by NAMD simulation?
This is a simple task. You just define a harmonic potential. The distance between this center and each DNA atom is calculated, and if any distance is larger than 5 nm, the harmonic potential would kick the DNA atom(s) back. As the selection of this center is arbitrary, you can simply choose the (0,0,0) point, and the definition of the harmonic potential is simplified to let all atoms stay within the 5 nm spherical region centered at (0,0,0).
There are also other ways to do this job. For instance, there are some designed functions to estimate the number of contacts between different regions/particles. With these functions, you can define that the sampled configurations in your simulation should have DNA-(0,0,0) contacts larger than some threshold.
A more physical regime to do this restraining work is really adding a spherical objects around your DNA system. For example, you can put some user-defined particles (e.g., carbon sphere) with a radius of 5 nm. The sphere only has vdW repulsion and no other favorable interactions with your DNA system. As a result, your DNA system is literally kept in this spherical region by the repulsive sphere.
Question
An electron is usually described as being a “point particle”. Collision experiments are interpreted as indicating an electron must be smaller than about 10-18 m. However, this size is incompatible with an electron also having physical angular momentum of ħ/2. An electron would need a radius of about 2 x 10-13 m and be rotating at the speed of light to have ħ/2 physical angular momentum. This conundrum forces physicists to postulate there must be an “intrinsic” form of angular momentum that does not involve rotation. However, the Einstein-de Haas experiment proves that reversing an electron’s spin with a magnetic field imparts physical angular momentum to a ferromagnetic rod. Do you believe there really is an “intrinsic” form of angular momentum that can be converted to physical rotation of an iron rod when an electron’s spin is reversed?
The alternative explanation is that experiments that attempt to measure an electron’s size have been misinterpreted. For example, if an electron’s electric field is considered a fundamental part of the electron’s structure, then it is ridiculous to ignore the fact that an electron’s energy is distributed over a much larger volume than 10-18 m radius. In fact, an electron’s classical radius of 2.8 x 10-15 m is the size where 100% of an electron’s energy would be in its electric field. A sphere with radius of 10-18 m and charge e would have more than 2,000 times too much electric field energy. The solution I have proposed incorporates an electron model that is a rotating quantized wave with a mathematical radius of 3.86 x 10-13m. What is your solution to the electron’s spin problem?
Taking the idea of Dirac as inspiration yields the following visualization: https://www.motionmountain.net/research.html#qed
Question
I performed experiment on dimple sheet structure(IMG_20220330_094533_881.jpg).I am simulating incremental sheet forming process of dimple sheet sandwich structure in Abaqus. The sheets are aluminum 1050. Sheets are bonded with epoxy rasin which is modelled as Tie. Surface to surface contact is there b/w sheet and tool.Tool radius is 5.5 mm. Truncated pyramid shape is used for forming. simulation gives the error [excessive incremental rotation of elements in elements set ErrElemExcessIncrementalRotation-step1.
There are total of 8 elements with excessive rotation ], fig(IMG_20220413_175556_439.jpg). How to fix this problem.?
Thanks.
In most cases, the unit has a problem, check your input units and the quantity of each parameter.
Question
Hello I am wondering how to calculate XRR density using the common formula for the critical angle of
θc ≈ sqrt(δ)
where
where the electron density is = 0.007/Angstrom^3
lambda = 1.544 Angstrom
The resulting value is much smaller than any reasonable critical angle?
What am I doing incorrectly?
That helps thank you.
Question
Hi
I would like to design a phase shifter for uniform circular array of array radius of 0.5 lambda which has 4 microstrip patch antenna elements, using cst software and 1 port.
Thanks.
FF
any references can you send
Question
Hi researchers,
I have used Amber16 to run a molecular dynamics simulation of my protein system for 50 ns. After the production run was completed, I have generated an MD trajectory with 2500 snapshots which I further analysed using the Cpptraj program. The issue is, after doing a few analyses using cpptraj, the results were generated in the .DAT extension which I can only open in Excel. I analysed the dynamic cross-correlation of all atoms (DCCM), hydrogen bond analysis, Radius of gyration and all the results were generated in the .DAT extension (file format). Therefore, can anyone suggest to me how to change the result file format or what are the software, can be used to view the results generated by AMBER 16? If there is an option in AMBER to visualise this file format, then kindly do let me know as it will help me to progress my research.
Thanks, regards
~Priya
Hi. You can use Gnuplot, MATLAB, Xmgrace etc. for plotting .dat files.
Question
Hi all,
How/where can I find radius of solvents (Acetone, Ethyl acetate, etc)?
Many thanks!
Question
Please see the attached plot of this type for your reference. How to plot M-R curves by solving a coupled ordinary differential equations using "NDSolve" package?
which code is used to plot these graphs, they look very intriguing ...
Question
Can the rolling ball radius tool be used alone to reduce background in fluorescent images? Why or why not? If not, what are some additional methods to further remove background after rolling ball has been applied?
Hi there and sorry for the late answer,
I usually find this method the most accurate and unbiased to remove background. The theoretical explanation abovementioned by Christopher B O'Connell and the references provided are perfect.
I) Minimizes user-intervention (potential sources of error and bias)
II) Since it's local, different values are subtracted to every pixel. Usually this is the best way to correct biomedical images unless you can assure a perfectly even illumination, which is often not the case (not due to the imaging system, but due to the sample)
Another option that some people use to remove background is to average several background ROIs (usually cell free regions, tissue free regions or un-labelled tissue) and perform an arithmetical subtraction of this value.
You can do this over the image in ImageJ by:
Process>Math>Subtract...
Or, alternatively, after listing the values, remove this value to all your ROIs.
Again, I'd never advice this method since the user intervention could introduce errors (not perfect sampling of all the cell/tissue free regions; (un)intentional bias towards different experimental sets,...)
As a plus, in ImageJ you can find a plethora of different filters and de-noising tools (Under Process>Noise and Process>Filters, respectively). Although these aren't strictly speaking background removal tools, they can help to improve your images if used correctly. All of them are well explained here:
Hope this helps,
J
Question
I am working on a numerical problem that involves large banded matrices, I am trying to solve the problem using an ADI scheme however the problem is really sensitive to the acceleration parameters I use (i.e. most choices lead to $\rho(T_{w_n})>1$), the problem tends to converge fast for the first iterations but diverges afterwards.
I tried to use some of the values of $w_n$ I found in literature and the one provided in Ref. [1]. seems to be the closest fit for my problem but still leads to a $\rho(T_{w_n})>1$.
For small problems I can use the power iteration and the Simulated Annealing proposed by Koutserimpas et al. [2] (since their suboptimal optimization parameters don't seems to work for me and leads immediately to a diverging result), but it becomes impractical for larger ones.
In Ref. [2] a linear dependence on the discretization for $w_n$ is proposed but I am not sure if it is a general rule or a quirk in their simulations. Since I was working with preconditioner on a multigrid as an alternative to the ADI scheme I was curious to know if I could extrapolate a general relationship between the spectral radius of a matrix for a discretization of $\Omega_h$ and it's upscaled smoothed version for $\Omega_{2h}$.
Is the linear dependence found in Ref. [2] a coincidence for their problems? Or is there some theorem I can use?
[1] Hadley, G. Ronald. "Numerical simulation of reflecting structures by solution of the two-dimensional Helmholtz equation." Optics letters 19.2 (1994): 84-86.
[2] Koutserimpas, Theodoros T., Aristeides D. Papadopoulos, and Elias N. Glytsis. "Applicability and optimization of the alternating-direction-implicit iterative method for the 2-D finite-difference frequency-domain solution of scattering problems." IEEE Transactions on Antennas and Propagation 65.12 (2017): 7166-7173.
Question
I have a dataset of binary images where each image contain a shape of the form of: circle, line or an arc, where each shape can have different radius, length or angle of the arc etc.
I am looking for finding a metric for comparing the images such that similar images that contains similar shape in close regions will receive higher similarity score (or low difference score)
Question
With the method of proton-seconds we can solve a great deal of problems easily. They define a definition for the radius of the solar system and predict the radius of a proton within its experimental errors to predicting the relative abundances of hydrogen and helium in the Universe from which the heavier elements are made in the interior of stars. It is doing physics with a chemistry methodology.
Deleted research item The research item mentioned here has been deleted
Thank you, I find your approach interesting too, we both seem to be working on the microcosmos and macrocosmos being part of the same method, you determine the electron-proton mass ratio and rotation of the galaxy from the same source... I determine the radius of the proton and radius of the solar system from the same source. What would you say the actual value of the proton radius is? Before 2012 or so I believe the experimental value was very different from what they determined after that and that neither agreed within experimental errors.
Question
The electron and photon are extensively interrelated, and therefore should share many common properties, equalities and laws. According to De Broglie, one such law is the Planck-Einstein relation, stating that as wavelength (i.e. radial orbit path) decreases, energy increases. An electron at a smaller orbit (today believed to be the ground state) most assuredly has a lower wavelength, and therefore should display a higher energy, not a “lower” energy level of the so called ground state.
Bringing this question up previously, two primary responses are typically offered... the "negative energy" aspect taught in high school, and the "pay no attention to classical mechanics" response. The last I checked, negative energy does not exist. Even it if did, a "zero" electron energy believed to exist at ionization is still greater than a -13.6eV at the believed minimum radius ground state, and therefore does not answer the question. As far as the second typical response, some sort of waving of the hands is offered, stating that the electron does not obey classical mechanics. Ok, I'll bite for argument sake, but then please explain why even the Schrodinger probability wave function also states that electron energy is minimum at a smaller radius ground state, and increases with a radial distance increase away from the proton. No so-called classical mechanics here.
I propose a model of Hydrogen for consideration, and welcome any peer review comments:
1) When the electron gains photonic energy, its orbiting radius is reduced and therefore its orbiting path per cycle decreases, equating to a higher cyclic frequency, equating to a higher energy per the Planck-Einstein relationship [so far so good, nothing strange here].
2) As it’s radius (r) decreases its Coulomb attraction force to the proton increases by r squared, and therefore so does its Potential Energy (PE) by 1/r (since E=F x dist). Therefore to remain in this particular lower radius increased energy level state, its orbiting velocity must then also increase to remain in this stable orbit, thereby increasing its associated Kinetic Energy (KE). [if you’re going to wave your hands here and say that classical mechanics doesn't apply to atomics, then state WHY and give an explanation, please don’t just regurgitate something you have read. Electrons have mass, and it is orbiting another mass. A very "classical" situation].
3) This increasing orbital velocity (frequency) has two limits: a) The speed of light, and b) Ionization "escape velocity" of the electron mass.
4) Once either of these velocities occur, the electron must then, a) convert completely into a photon at the speed of light, b) completely ionize (escape) from the proton, or c) convert part of its energy into a photon plus transform itself to a lower energy (higher radius) energy level [nothing too strange here unless there is a classical hand waving fetish].
In other words, attempt to purge the incorrect visualization thinking that as an electron gets further and further away from the proton, that it is closer and closer to becoming ionized. Attempt to think about WHY and HOW the electron would want to ionize, and you’ll come up with the above postulate. In fact, attempt to think about WHY only particular wavelength photons will be absorbed by the Hydrogen electron. Perhaps it is because it has the same geometric orbital size or a harmonic of that size. I have actually derived this harmonic to be the Fine Structure Constant / 2 utilizing classical mechanics, and by doing so, believe I have also discovered why and how the quantum aspect of the electron energy levels must occur.
J.L. Brady: I agree with you that probabilities and uncertainties being the bedrock of Truth we are seeking is very uncomfortable. we have an intuitive feeling that Truth has to be deterministic. I will continue to follow your work. thanks.
Question
If radius of rotor is 5 cms while the other one is of 10 cms. Both are employed to separate equal amount of same mixture at same temperature and time. Would it require same RCF or different RCF?
From this site info [1]:
G-force can be different if Rotor Radius is different. How to Calculate G-Force:
The Force exerted on a sample in a centrifuge is a function of the rotation speed of the centrifuge (RPM) and the radius of the rotor. 👇👇👇
If you know the RPM, the equations to calculate G-Force are:
▶▶ In Centimeters: RCF or G-Force = 0.00001118 x Rotor Radius x (RPM)²
OR
▶▶ In Inches: RCF or G-Force = 0.0000284 x Rotor Radius x (RPM)²
Question
How to determine or calculate the dimensions of the tensile specimen: calibrated width (b1), b2, and R (radius)? Note that the thickness equals 1.5mm
hi Nataliia Chernovol; Thank you very much for your help, it's very kind of you, if you have the EN ISO 6892-1 standard - Proportional specimen send me if possible. For the samples I have an overall width of 10mm, could it be that l0 = 8mm and the overall width is 10mm?
Question
I want to enter my temperature as a function of radius as T(r,Θ) = T0 * (r/r0 ) * cosΘ. where theta is 0 degrees, r0 is outer radius, T0 is outer temperature. my question is how to build a relation between radius and temperature in APDL, then?
This is indeed a very good question. What I understood from your question is that you want to apply a temperature boundary condition which is function of radius and angle and apply it on a cylindrical shape feature. I did something very similar for solving an thermoelectrical problem sometimes back and developed a script in Mechanical to do so, however, with a little bit of work you can do this manually in workbench and then use this idea to develop your code in APDL (which I’m not expert in it!!). There are 4 steps you need to take that I explain them in detail.
1. Since temperature is a function of radius and angle, you need to measure these coordinates first. Therefor, you need to create a cylindrical coordinate system and place it on a proper location which enables you to measure required coordinates.
2. Select the future that you want to apply the temperature on (e.g. body or surface) and convert that feature to nodes by using the function that is shown in Capture.jpg.
3. From “Home” menu, select “Selection Information” (in “Tools” context). Adjust the coordinate system to reflect the coordinate system you just created. Now you have something very similar to Capture2.JPG. Right click on one of the table cells and export the table to an excel file format. You can calculate the temperature on each node as a function of radius and angle now.
4. Last step would be applying temperature on each node by using command snippet (D command).
This is the only way I know for applying unconventional BCs.
Question
-The atomic radius of lanthanum is approximately 0.35 nm, as opposed to 0.3 nm for water molecules.
-Seawater sample also contain organic contaminants such as Mg, Na, etc. some of them with the same molecular size as lanthanum.
Question
As we understand, for a matrix A with eigenvalue c,
||cX||=||Ax|| implies |c|||X||<=||A||||X||, so |c|<=||A||.
This concludes that norm of a matrix can be greater than eigen value. In view of this can we imply that just to have spectral radius of a matrix less than 1 guarantee ||A||<1 and consequently stability of a system.
Ultimately, I will be looking for stability of a numerical scheme. Can you please suggest me a criterion that is sufficient to have stability. Clearly I cannot rely on spectral radius unless I am proven otherwise.
Question
Through the telescope, Astronomer Edwin P. Hubble first observed the distribution of galaxies in space in 1929. Hubble found that most of the galaxies outside of the local group are receding from us, and the ones farther away are receding the fastest. From Hubble’s observation, scientists discovered that the universe is expanding.
Yet! in my research results saying-
“Gravitational worlds, they are moving or changing the orbit with all their family members depending on the nuclear energy of each other”. Circumstantial evidence: the super cluster of galaxies, clusters of galaxies and galaxies, that there are the black holes of other kinds of energy in the deep gravitational world, they are moving or changing the orbit with their all family members depending on the nuclear energy of each other. According to this information; as I see it, all the gravitation worlds of the universe have become the victims of rolling or moving into the oval orbits of critical radius. The gravitational worlds of the nuclear circle of the gravitational worlds, are expandable with others in the orbits around the nucleus, resulting in it seems that the universe is expanding. See reality in our solar world about moons, planets orbits system and also see in our galaxy Milky Way stars orbits formula. From the nuclear of the circle of the gravitational force, the gravitational worlds are expanding from each other being moved around the radius of the nuclear inside the circle or in the difference of movement their distance boundary are always increasing in the eternal radius. Again law of philosophy: “An individual respective very location is the present and the rest all locations are of the deep of the past”. In this way; see big bang is earliest known event. So, see scientist Edwin P. Hubble discovery is blunder about universe is expanding because expended velocity of the universe is going forward towards the critical radius.
Question
Here, it means the distance from a point on the surface of the cylinder to the point itself(taking a uniform route with out twisting).
Thanks!
Dear
Sergio Flores
thanks!
Question
Hi friends
I am modeling a tunnel in the PLAXIS software whit plate (shell) element.
As you know tunnel has an inner and an outer diameter. When we want to create the material we can enter the thickness of the plate element and when we create the geometry we inter one single radius of the circle(radius of the tunnel).
Now my question is:
Which side does PLAXIS consider the thickness of plate elements? and what radius should be used, inner, middle, or outer?
Hi!
According to the Plaxis´s Reference Manual: "The (equivalent) thickness (in the unit of length) is the material cross-section area of the plate across its major axial direction per 1 m width."
So I guess it is considered in the middle.
Question
What factors affect the sharpening of this peak, for example, if we want to have a sharp point at a certain radius , what parameters should we manipulate in the synthesis?
Dear Mona, thank you for your interesting technical question. For some useful information please have a look at the following article which might help you in your analysis:
Accurate characterization of full pore size distribution of tight sandstones by low-temperature nitrogen gas adsorption and high-pressure mercury intrusion combination method
This paper is freely available as public full text on RG. Also please check the answers given to the following closely related questions which have been asked earlier on RG:
How can I estimate the accurate range of pore size distribution from the BJH (Barret-Joyner-Halenda ) plot?
and
What is the pore size distribution by BJH method?
I hope you will find this information useful. Good luck with your research!
Question
I am planning to analyze the Hertzian contact stress and contact radius for Pin-on-dis wear testing, where pain with the flat end was employed. If possible, I would like to know whether I can treat the contact between the pin and disc as circular contact or point contact.
Hello Pavel,
I agree that if pin is flat then hertz model can not ne used. Then, the contact pressure can be calculated as load/area. It comes into conclusion that modulus has no effect on pressure in flat on flat contact case i.e., flat pin of two different materials will have a same contact pressure under a constant load for a particular counter body? Also, why we dont consider modulus values in this case?
Question
Hi
One can use the 'measure tool' to calculate the area of any 2D geometry in COMSOL.
I want to know how to do it programmatically in COMSOL.
In my application, I need to use a parametric sweep to calculate, for example, the area difference between a circle and a square over a range of circle radius and square side.
Hi Ravinder,
if I understood correctly, the best way would be to run a prametric sweep changing the radius of the circle and then do the following:
Under the result section, select:
• derived values--> surface integration
• Add expression --> model --> geometry --> dom entitity index
This expression computes the area of the selected surface for each geometry of the parametric sweep.
Is this what you are looking for?
Question
I was doing pictures. It was possible to extend the numerical solution for the place that people call the Schwarzschild radius. Now you can describe how g_ {00} behaves,
1. Somewhere around 50 Schwarzschild radius it graphically merges with Schwarzschild's solution.
2. There are no peculiarities in the area of ​​the Schwarzschild radius.
3. The solution apparently exists everywhere, except for the origin.
4. g_ {00} is strictly positive (time does not stop).
5. Somewhere around 0 <r <3.4rg quickly decreases to almost zero. This is exactly close to the estimated radius of neutron stars. Time in this area almost stops.
6. So far, the solution has been extended to 0.98. The value for g_ {00} is about 10 ^ (- 260).
Question
Radius of curvature & Polar (x y)coordinate value and angles are known at multiple points (500) on cornea How to convert it in wavefront( zernike polynomial)& 3D model.
Great question, am curious to learn this as well. Take care.
Question
How intensity(peak intensity) is measured experimentally in the gaussian exponential heat source used in the laser powder bed fusion process? And in the heat flux equation, the beam spot radius is taken at which intensity falls to 1/e^2 of peak intensity. How to measure this radius. How can we choose this radius value? Please anyone explain. I searched many research papers but didn't get apt information regarding this
the equation is in 2.1.3 in this paper
Also check..
Determination of heat source model for simulating full penetration ...
Question
My coauthor and I have a (the) solution to an inconsistency in units of measure in rotational mechanics that has induced BIPM to assert that Joule and Newton*meter are not interchangeable units in rotational mechanics(!) See https://www.researchgate.net/publication/342338981. We have not found a journal that will review the article. I believe the main obstacle is that metrologists feel that meters is the "obviously correct" unit of measure for radius of rotation, whereas the principle of general covariance requires that radius of rotation have units meters/radian. We seek a refereed publication that will review the work and publish it. Any suggestions?
You can send your manuscript in the OPEN PHYSICS journal (Previously Central European journal of Physics). This journal covers wide field of mechanics, physics, etc. Not only that, if the editor finds another journal suitable for publication of your manuscript he/ she will inform you accordingly.
Question
I am designing a novel type of power system capacitor, and a colleague suggested I investigate what effect the induced magnetic fields would have on the device. The device is like an old airgap "butterfly" capacitor which will have charged discs rotating at 60 Hz. Based on some crude calculations, which are attached, I found the force of the magnetic fields to be an exceedingly small fraction of the electric fields such that: F_b/F_e = 3.16E-12; for a 1-meter radius device rotating at 60 Hz. Are these calculations approximately, correct?
Muhammad Hamza El-Saba Thank you for your response; however, I am specifically inquiring about the induced magnetic fields from the displacement currents within the capacitance of the device, such as the equations provided in the attachment. I am familiar with Foster diagrams and they cannot be used to answer this type of question.
Question
Absorbance (A) = (Aλ vis-max x A700) pH 1.0 0 (Aλ vis-max x A700) pH 4.5
TAC (mg/L) = (A × MW × DF × 1000)/(ε × l)
MW: the molecular weight, calculated as cyanidin-3-glucoside (449.2); DF: the dilution factor;
l: the cuvette radius, 1 cm; ε: the molar absorptivity, calculated as cyanidin-3-glucoside (26,900).
For justification of results it is necessary to run reference standard.
Question
To begin with, where is the mass of a black hole? If we are not able to define a location in spacetime for that mass, we could think just about the deformation of spacetime around the event horizon.
How does Hawking radiation reduce the energy and mass of the black hole? Talking about particle pairs, does the negative energy particles annihilate with the particles inside the event horizon and if so, could that interaction which occurs inside the event horizon affect the event horizon radius?
In response to your assertion "I want to discuss about the evidence for the existence of black holes," made on this ResearchGate discussion thread on August 10, 2019, I am sharing a fairly recent illustrated article which you may access by clicking on the SOURCE LINK below.
Question
If a black hole swallows an object of mass "m" and the initial mass of the black hole being "M", then does the total mass of black hole be = M + m?
Will the Schwarzschild radius change accordingly?
Your explanations about processes in the interior of stars uses terms of ideal gas theory. But actually, nuclear physics terms are needed.
Question
I'm dealing with vesicles (not liposomes, so I dont know the composition and I can't do any assumption of their molarity based on their concentration and hydrodinamic radius), derived from erythrocytes. I would like to count them. I dont have access nor to ZetaView for Nanoparticle tracking analysis or to a resonant mass measurement equipment. We just have a Zetapals, which also counts particle/seconds but I'm not sure about reliability.
I was thinking of some fluorescence method... Do you have any suggestion?
The article below presents simple mathematical equations to count particle numbers of different types:
Mozafari, M.R.; Mazaheri, E.; Dormiani, K. Simple Equations Pertaining to the Particle Number and Surface Area of Metallic, Polymeric, Lipidic and Vesicular Nanocarriers. Sci. Pharm. 2021, 89, 15. https://doi.org/10.3390/scipharm89020015
You just need to know how much material (ingredients) you took to make your vesicles and have idea about average particle size. The equations will give you:
NUMBER OF PARTICLES PER MILLILITER.
let me know if you need clarifications.
Question
is there any standard formula for root fillet radius for DIN 3960 ?
You should determine the root fillet of the spur gear and divide it with cos of the helix angle at the reference cylinder of the helix gear.
Question
I have the the constants for air density, radius of pipe, Radius of the propeller, and the rpm of the propeller. I need to find the inflow air velocity and mass flow rate of the air and the outflow mass flow rate and velocity of the air from the propeller. is there a formula, method or theory for this?
The information given in your question is insufficient. The flow velocity and flow rate will depend on the geometry of the impeller (e.g. blade angle).
Question
Hey out there!
I'm working with bat activity measured above forests, running a GLMM in R which uses bat activity as response and some habitat variables such as the amount of roost sites in a 200m radius around the measurement point, distance to water and distance to forest border as explanatory variables.
The response I'm working with is calls per day, means that I divide the actually measured amount of calls at a studysite by the number of measurement days. I do this because we measured for three month daily, but got some failure days for technical reasons.
A Poisson distribution works well, even if it's not realy count data anymore.
My Problem now is that for Species we didn't measure often, calls.day is a small number (e.g. between 0 and 5), in this case a rounded calls per day would be too much manipulation. Using calls per day more precise as an decimal number, birngs many warnings. Logically the GLMM i built is made for count data and R wants to see an integer.
Does anyone have an advice how to deal with this?
Hello everyone, I am having the same issue.
I am trying to do a negative binomial GLM and I cannot get the offset to work. Does the offset have to be logged for negative binomial too or just Poisson?
Question
Hi,
I tried to simulate the SPECT system with GATE and I could visualize interactions in the detector. However, I would like to visualize source energy distribution too.
I tried to simulate a SPECT system and set up source as below:
/gate/source/SourceConfinement/gps/type Volume
/gate/source/SourceConfinement/gps/shape Sphere
/gate/source/SourceConfinement/gps/centre 0. 0. 0. mm
/gate/source/SourceConfinement/gps/particle gamma
/gate/source/SourceConfinement/gps/energy 140. keV
/gate/source/SourceConfinement/setActivity 740000. Bq
/gate/source/SourceConfinement/gps/angtype iso
I didn't mention any energy distribution here. So, what will be the actual energy distribution with this simulation and is there any way to plot the source energy distribution?
Hi,
You can simply use the Energy Distribution actor from GATE and attach it to your detector.
Question
I have established a set of variable radius plots to serve as a CFI plot network. I took radial cores, measured heights, dbh and distance from plot center so that I could look at historical volume growth.  I then applied to distance-variable estimators to the data. I am hoping to find a few examples to compare my results with.
RELATIVE EFFICIENCY OF POINT SAMPLING CHANGE
ESTIMATORS
Guillaume Therien
The technique was developed for VP sampling. It was also designed into the BC vegetation inventory, and is being done by several private companies. It's easy to add to existing PSPs.
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In general terms, how we select a material for doping? While doping, is it necessary to have a element with low ionic radius in to the host material having ionic radii larger than the dopant.
Can anyone clarify me this part.
From my experience, there is a critical role for the ionic radius of the acceptor dopant on the stability, sinterability, and proton conductivity of barium zirconate. In Particular, when dopants such as, (Al, Sc, In, Lu, Tm, Y, Gd, Sm, Nd, and La) are added to zirconate, the lattice mismatch between the ionic radii of the dopants and Zr ion is critical.
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Weighted average distance is calculated between SHS and demand points lying within the 'radius of influence'
Try algo-rhythms related to 2D spatial plains, such as the Travelling Salesman problem, and the Bees v Nectar problem, and the Gestalt constellations problem. The factors of 'distance' could be proximity and relay proximity (confluences), volume, slope direction, slope ratio, and obstruction such as vegetation. Negligible factors could be silting, turbulence, and bends. Disaster management agencies use satellite scans and a flooding simulation programme. In practice, test colour tracers in different channels.
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Given that the radius of proton is smaller than lithium ion, so I am wondering whether garnet-type solid electrolyte is a good proton conductor or not
Sorry I don't master the Goethe language. The French translation is "Tester avant d'étudier", or "Testing is above studying". For me, testing is just the beginning of studying.
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I am interested how to find aggregation rate using dynamic light scattering data? I can obtain hydrodynamic radius dependence on time. I need not only answer but sources too.
What system are you studying?
You probably know that it's possible to obtain an aggregate index from DLS by comparing the forward and back scattering results (where the larger aggregates are favored in forward scattering). See attached application notes.
As DLS is looking at diffusion coefficients which may need many seconds (old units were cm2s-1) to determine accurately. Hence your aggregation rates should be fairly slow (over a few minutes minimum) to capture the growth. I have done this successfully with clays (unpublished work) where I could watch the (slow) first order growth, sonicate the sample outside the cuvette, and repeat the process.
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I want to find out the volume of material remove by wire edm process for that i have to find out crater radius and depth.
If file will extract in stl file format than i can easily measure the radius and depth in solidwork.
please suggest me what i have to do.
If any other method which is accurate and precise than please let me know.
Very interesting question. Extracting STL file from APDL is a bit tricky and difficult. You can use this macro to generate STL file which works with both TET and HEX mesh. I think you used HEX mesh right? A big thank goes to Eric Miller from PADT who wrote this awesome macro.
After you exported the STL file you can use the following method to calculate the volume of the STL geometry.
1. Open a new SpaceClaim geometry and then open your .STLfile.
2. Use shrinkwrap function located in cleanup set of Facets.
3. Select imported facets.
4. Click on preserve feature (You need to set the gap size to reasonably lowest possible value).
5. Then click on complete.
6. Now you can convert created shrinkwrap to solid.
7. After you transferred the STL to solid then you can measure the volume using the mass properties in inspect set of measure.
Hope this answer helps and please recommend if it worked for you.
Thanks,
Question
I've been told:
“As measured by proper time, a radially falling traveler quickly reaches and crosses the critical radius of a black hole. The reality that the traveler quickly reaches the critical radius appears to the distant observer to take an inﬁnite amount of time because of the propagation of light.”
But let’s test this with a thought experiment:
Put a reﬂector on the back of the traveler as he freefalls towards the event horizon of a black hole. Have a distant observer periodically shine a light beam at the traveler. Use the Schwarzschild metric to calculate the radial location at which the faster moving light beam will overtake the slower moving traveler and reﬂect back to indicate the location of the traveler to the distant observer. No matter how much of a head start the traveler has before the light is turned on, according to the Schwarzschild metric the light will always overtake the traveler before the event horizon is reached. Let the distant observer continue to shine light beams at the traveler until the distant observer observes that the black hole evaporates because of Hawking radiation. Granted, this will take a long time. But the entire time, the reflected light will continue to reflect back from the traveler showing that the traveler fails to reach the event horizon before the black hole evaporates.
How can this be?
Richard: Given that the universe is 300 billion years old, let's do the same thought experiment, starting 300 billion years ago. After 300 billion years of traveling, the traveler has not yet reached the event horizon. This indicates that never, since the beginning of the universe, has anyone or anything crossed the event horizon of a black hole.
Question
[1] In this experiment, we use a very large virtual world, with a dimension of 30*30 units, total number of avatars is equal to 25000, and the number of servers, 16. The radius of the Area of interest of each avatar is equal to 0.5.
[2] To generate a simulation environment, we randomly position 100 cloudlets and 500 players on a 1,000 meter square grid. Players are partitioned into 20 regions
[1] An efficient partitioning algorithm for distributed virtual environment systems | IEEE Journals & Magazine | IEEE Xplore
[2] Delay-Sensitive Multiplayer Augmented Reality Game Planning in Mobile Edge Computing | Proceedings of the 21st ACM International Conference on Modeling, Analysis and Simulation of Wireless and Mobile Systems
A good job there
Question
Hello all,
I want to know how can I calculate the geometrical properties of helices.
Consider any α-helix of proteins, how to get informations about their helical pitch length, reduced pitch length, helical angle, turn, radius (or dimeter) etc from their .pdb or .xyz files.
Any suggestions are welcome.
alpha helix is a double helical path that can be parametrized with two different helical equations which differ by a period and thus, the double path appears to be a spiral staircase. so, one side or railing of this stair case can be x1 = a + bcos(t), y1 = a + bsin(t), z1 = kt . other railing of the stair case may be seen as x2 = a+bcos(t +c*pi), y2 = a + b sin(t + c*pi), z2= kt.
Question
How does LAMMPS identify the atomic size of atoms, does this information exist in potential file?
Dipankar Roy Thank you
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I performed a minimization simulation of a water box using the tip3p water model in NAMD. The water box was in a sphere of radius 20nm and sphericalBCk1 of 10. The water box changed its shape from a cube to a sphere (almost). My question is why is the water changing its shape when the volume is supposed to be constant?
Isn't the sphere imposed by setting the spherical boundary condition with sphericalBCk1 parameter?
Question
I have designed a flexible antenna and observed that as we increase the radius of curved surface the gain and antenna performance increases and then on further increasing radii it decreases, however at planar surface performance is optimum.
I have done a literature survey but unable to find the reason behind it, kindly help me.
Thanks
The planar surface performance will have optimum always because such design has a bigger effective surface compared with bending a flexible antenna. When you increase the radius of the curved surface then the gain of the antenna increases. By further increasing of radius you should get results similar to planar surface.
Question
The shell is made of metal, the inside and exterior are inviscid fluids.
The ratio of shell thickness to radius (h/a) ranges from 0.5 % to 2 %.
I have written Fortran programs for the models described in the papers listed below but they are all unsatisfactory in some respect. Hickling used full exact elasticity, but there seem to be misprints in the paper. The others are thin-shell models and yield a resonance frequency of zero at particular values of h/a. I will give further details to anyone who asks and is acquainted with the issue.
Hickling 1964
Lou & Su 1978
Felippa & Geers 1980 (same result as preceding paper)
Dean & Werby 1992
Do you have measurements or a numerical model to compare with (validation/verification)? If not, then it is difficult to judge which is 'best', unless there are some clear errors or unrealistic assumptions in the different models.
Question
The different paper doesn't agree on the actual circular trihedral corner reflector RCS's formula.
In another term, is there the pi number in the formula or not?
15.50314 r^4/wavelength^2 is the RCS of one quadrant seen at 45 deg to 2 faces and parallel with the third face. The RCS will increase as the projected area increases (as the square of the projected area), but I don't expect the projected area will increase as much as root pi which is what is needed for the first formula. It only increases by root 2 when rotated 45 degrees from normal to one face.
I expect the second formula is correct (but approximate).
One quadrant (ignoring all the others because they will not contribute when 3 faces of one quadrant are visible) has area pi r^2/4, so rcs normal to one face is 4 pi (pi r^2/4)^2/wavelength^2. Rotate 45 deg and all reflections still hit another face, and width of reflector increases by root 2, so RCS of quadrant is 8 pi (pi r^2/4)^2/wavelength^2 which is 15.50314 r^4/wavelength^2.
Rotation so the third face can be seen will not result in the whole visible area having the required reflections, so the projected area will not increase by even as much as root 2. It probably drops and then rises to something like 15.6 r^4/wavelength^2. Try the geometry!
Question
I have a sample that has rectangle-like particles. I want to perform particles measurement on them using ImageJ Software manually, by which I will pass a straight line on them to determine their lengths as diameter sizes, but I am confused because the particles are not circle-like. The measurements that I will get are not suitable to be determined as diameters of the particles, but they are most likely to be regarded as rectangle's perimeters instead. So that I'd like to ask, what strategy should I do to get the measurements that can be regarded as particle's radius sizes?
Thank you in advance if you can provide me some answers or a helpul explanation.
Hi there,
Sorry for my yesterday's answer. Actually if you go to
Analyze>Set measurements...>Bounding rectangle (Checked)
you'll get the size of the rectangle-like particles (width and height). With the long side of the rectangle I guess that you can get the info you were looking for.
Cheers,
J
Question
We live in the center of a sphere of radius 13.7 light years constituting our Universe. The big bang theory considers the state of our universe before the expansion starts from an original point located somewhere around us.
Suppose there is a conscious life form somewhere in our universe. Their universe does not overlap with ours and their big bang takes place at the center of their sphere.
Is there a reason for their expansion to coincide with ours?
And there should be as many big bangs as there are consciousnesses.
The easiest way to solve this paradox is to assume that we are the only consciousness in the universe, right?
And, there we are brought back to middle-aged thought where man is at the center of the world, which raises the question of the origin of life.
In short, I am very uncomfortable with this aspect of the big bang.
Dear Charles,
I think you are confusing the observable universe with the BigBang, apart from that keep in mind that the BigBang is defined for 4 dimensions and you are only thinking of 3.
Your discomfort is very easy to solve, there is only exist what is proven and verifiable. The "could" have no place in science
Question
How can I check the regularity of my fabricated photonic crystal arrays? (for reference, one hole/pillar radius is 300 nm, can be either square lattice/triangle lattice).
I can measure the hole size by SEM, but cannot measure lattice constant, especially with 3mm by 3mm large arrays.
use the program ImageJ
many applications have been written to it. find what you need
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The various parameters taken are:
2. Span
3. Diaphragm arrangement
4. Number of Elements.
5. Boundary condition
6. Cross-section.
Question
I am building an integrating sphere from some aluminum hemispheres. They are not entirely spherical when put together. One is slightly flattened on each half. The other does not entirely complete the radius so it leads to a slightly elliptical shape ( about 51.5mm x 48.5mm dia).
Knowing what I do about integrating spheres, the concept is to be sure the light is evenly distributed on the walls of the sphere before absorption of the paint finally quenches the incoming light.
In the case of the flattening I would think that if the light lands such that it bounces between the two flattened surfaces, the distribution effect will be highly perturbed. In the case of the slightly out-of-round sphere the result is not so obvious.
I think the only "easy" solution is a ray-trace which I don't have access to. I looked thru a lot of literature but I don't see this issue addressed. Even with a commercial sphere I am sure there is some degree of "out-of-round" nature and there probably is some disturbance to the result.
I am just curious if anyone has found any information on this or has an educated guess on the degree of sphericity required for a reasonable sphere.
Thanks
Fritz
Sorry for the late reply- apparently Researchgate does not send alerts via email.
At any rate thank you for your input.
Spectrolon and similar products are very expensive so I will be using Barium Sulfate mixed with paint having and LRV of around 92.
Fortunately the work I am doing will be in making comparisons and approximations so having a sphere less quality than a commercial one will probably be OK.
cheers
Fritz
Question
In my opinion we cannot find characterization of such graphs in the literature.
The minimum vertex degree is non-negative, while the least eigenvalue is non-positive, so the equality is attained iff the minimum degree=least eigenvalue=0, which further corresponds to the graph without edges known as the empty (or totally disconnected) graph. Its only eigenvalue is 0, and the maximum vertex degree is also 0. Thus, this infinite family of graphs is the unique solution.
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I am carrying out simulations using Smoothed particle hydrodynamics, in which the domain is meshed as particles distributed over it. What should be the volume of the particles in comparison to the domain volume. For instance, if we have cubical specimen of certain volume which contains n number of spherical particles each of radius r, then how to decide the radius (or volume) of each of the particle.
Thanks and Regards.
I would suggest a mesh refinement study. Start with a small number of particles and measure some variable you are interested in (stress, strain, etc). Then increase the number of particles and measure the same variable again. Repeat this process until you no longer see significant changes in the measured variable.
You can plot this process with the number of particles as the x axis and the measured variable as the y axis.
I also realize that SPH doesn't have a mesh, but mesh refinement is a common term for this process, since it's usually used for FEM.
Question
I am using molecular dynamics simulation for nanoindentation on a graphene sheet, interested in calculating hardness and young modulus after complete deformation. Here I am using spherical indenter. Indenter size 10 Angstrom and maximum indentation depth is 40 Angstrom. 𝐴 = 𝜋(2𝑅ℎ𝑝 − ℎ𝑝 2 ) ≈ 2𝜋𝑅ℎ𝑝 the approximation is correct only when the indentation depth is small compared to the radius of the indenter (R). So in my case indentation depth is greater, so which equation I should use.
Thank You Sir.
Question
If we expand an iterative system to quintic terms，the coefficients of quartic and cubic terms are both zero. What is the meaning of the quintic coefficient？ Is the coefficient of quintic term related to the radius of limit cycle？ Let a be the quintic coefficient，does a<0 mean supercritical Neimark-Sacker bifrucation?
Thanks for your reply. This problem is a very interesting phenomenon, because the divergent variable of judging N-S bifurcation is zero. As far as we know, there is no literature to analyze N - S bifurcation in the calculation of quintic term of normal form. This may be a new topic. Thank you again for your kind reply.
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I am trying to find the theoretical diffusion constant of the Co(bpy)3 3+ (or Co(bpy)3 2+) complex in acetonitrile.
I also tried to calculate it by myself by using the Stokes-Einstein equation . Nevertheless, my approximation for the radius is not good enough and I don`have the elctrical mobility of Co(bpy)3 3+ .
If someone know where I can find these values, I will be very thankful.
Question
I have 83 samples of wild boar (i.e. large mammal, moderately motile) whose sampling locations were obtained by randomly setting the coordinates in green areas (according to Google Earth imagery) within the municipality of collection. In this sense, when more than one animal was sampled at the same municipality, I have the same coordinates.
Since I want to perform landscape genomics analysis with a population-based approach (because of the uncertainty associated to the individual coordinates) I identified 9 “clusters” by drawing a 10km radius buffer around each unique location (i.e. one record per municipality) and clustering together all the individuals within the areas that would overlap, while discarding the stand-alone samples. In doing so, I verified that the clusters would include only individuals with at least 50% assignment to the same genetic cluster according to ADMIXTURE analysis.
Now, how can I report for each cluster the environmental variables from the Worldclim database? Should I first find the centroid of each cluster and then retrieve the value for that location only, should I retrieve the value for each sample included in a cluster and compute the mean? Any suggestion would be much appreciated!
Yeah thank you Md. Ashiqul Islam but I've already read a lot of papers and tutorials - included the first two references of yours; I was looking more for a personal opinion
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