Harmonics - Science topic

In a transition state structure, the frequency corresponding to the reaction coordinate is negative. This is the characteristic feature of the TS structure. it will not go away if your TS is correct.

For other negative frequencies in TS structure or other structures, you can simply remove them by adding displacement manually in the result manu--> vibrations --> manual displacement. Then reoptimize structures and recalculate vibretional frequencies. After a few trials, unwanted negative frequencies will be gone.

Hi Audrius Merfeldas ,

I did not find the link you mentioned to be very helpful, so I went in search of original source materials. I first tried Wikipedia: https://en.wikipedia.org/wiki/Doppler_radio_direction_finding . Their explanation of how pseudo-Doppler DF worked was that the technique used phase differences. They also referenced a 1987 book [1], which also mentioned on p. 122 that the technique, pseudo-Doppler DF, was also called "sequential phase" DF. Chapter 9 of this book shows one how to actually build such a DF, and it mentions a number of pitfalls when trying to get such a circuit to work: 1) multipath (p. 136), and 2) grounding of the non-active antennas (the non-active antennas must float, electrically, if they are grounded they tend to reradiate the incoming signal, see p. 130).

[1] also referenced a 1981 article by David C. Cunningham on desining and building a pseudo-Doppler DF, see [2]. The article also mentioned that Cunningham had patented his design. I looked up his US patent (granted on Novmeber 5, 1985), US Patent No. 4,551,727, on the following URL: https://ppubs.uspto.gov/pubwebapp/static/pages/ppubsbasic.html To obtain a PDF of a US patent, simply enter the patent number, without its commas, in the "Quick lookup" field at the top of the page. Cunningham's patent cites the June 28, 1941 US patent, US Patent No. 2,414,798, by Horace T. Budenbom showing the rotating antenna DF - the word 'Doppler' was not used. The antenna at the edge of the rotating disk phase modulates the incoming signal. Cunningham's patent also cites the 1947 article discussing the square array of electronically commutated aerials [3], notice the title of this article.

[1] Joseph D. Moell, Thomas N. Curlee; Transmitter Hunting, Radio Direction Finding Simplified; TAB Books; 1987; see Chapter 9 Doppler DF Units, pp. 120-141; URL: https://archive.org/details/curlee-t.-n.-moell-j.-d.-transmitter-hunting-radio-direction-finding-simplified-1987-tab-books

[2] David Cunningham; DF Breakthrough!; 73 Magazine; Vol ...; No. ...; June 1981; pp. 32-46; URL: https://archive.org/details/73-magazine-1981-06

[3] C. W. Earp, R. M. Godfrey; Radio direction-finding by the cyclical differential measurement of phase; Journal of the Institution of Electrical Engineers, Part IIIA: Radiocommunication; Vol. 94; No. 15; March-April 1947; pp. 705-721.

Regards,

Thomas Cuff

You could perform a transient vibration recording during the start (or shut-down) of the compressor until it reaches its nominal speed and visualise (waterfall display) the dominant harmonics (maybe the unbalance is not the predominant one?) and if they evolve smoothly with the square RPM (if they trigger some structural resonance you will see bumps in the waterfall)

Did YOU get solution @youssef?

The keyword FREQ requires the calculation of frequencies in the harmonic approximation and FREQ=anharmonic in the anharmonic approximation. See details here https://gaussian.com/freq/

Please check the surroundings. If the earth around inverter is having many installations with leakage currents the Ground potential itself increases.

Check system Ground/neutral voltage wrt Earth at both locations. This may give hint.

Thanks Stephen, I see Patrick has done a lot on pulse wave so perhaps he has some info on ECG also and Ive messaged him.

Dear doctor

Go To

On mixed polynomials of bidegree (n, 1)

Mohamed Elkadi and André Galligo

December 17, 2014

"Abstract Specifying the bidegrees (n, m) of mixed polynomials P(z, z¯) of the single complex variable z, with complex coefficients, allows to investigate interesting roots structures and counting; intermediate between complex and real algebra. Multivariate mixed polynomials appeared in recent papers dealing with Milnor fibrations, but in this paper we focus on the univariate case and m = 1, which is closely related to the important subject of harmonic maps. Here we adapt, to this setting, two algorithms of computer algebra: Vandermonde interpolation and a bissection-exclusion method for root isolation. Implemented in Maple, they are used to explore some interesting classes of examples."

Mr. Sadri, I have met the same question, How did you solve your problem? Thanks

In certain cases, distance can indeed play a role in creating sound or affecting the perception of sound. One example is the phenomenon of resonance. When an object or a medium vibrates at its natural frequency or multiples of it, it can produce sound. Resonance occurs when an external force or stimulus matches the natural frequency of an object, causing it to vibrate and generate sound waves.

Regarding your mention of Earth, Sun, and Moon, they do not directly create sound in the conventional sense. However, their interactions can generate various waves or vibrations that are interpreted or detected as sound by scientific instruments. For example, solar flares or coronal mass ejections on the Sun can produce intense electromagnetic waves, including radio waves, which can be converted into sound waves for analysis and interpretation.

Similarly, the movement of the Earth's tectonic plates during earthquakes can generate seismic waves, which can be detected and converted into audible sounds by seismographs. These sounds are not audible to human ears directly but are converted into frequencies within the audible range for analysis.

In summary, while distance alone does not create sound, the interaction of objects, resonant properties, and other physical phenomena can generate vibrations and waves that we interpret as sound.

Thank you, and Mostak Ahamed for your proposals. I'd like to tell you that I know very well about interpolation. But please, read again my question. Interpolation works correctly for the case when frequencies of signal and its sampling are very different.

To plot harmonic light intensity as a function of the polarization angle Ψ by two-dimensional and polar representations, you can follow these steps:

Note that the specific details of the plotting method will depend on the software or programming language being used. However, the general approach outlined above should be applicable to most cases.

alignment or misalignment between strategic thinking and organizational culture impacted an organization's ability to innovate, adapt, and achieve long-term success,

my opinion: this is relate to knowlegde management.

if an organization want to innovate, adapt an achieve long-term success, first the company need to be aligned the strategic thinking with organization culture.

Thank you for your attention.

Yes I am exciting a GaAs quantum dot with light in visible ranges to study the spin-orbit interactions effects. I have studied theoretically. If I can investigate experimentally, I can compare their results. Unfortunately I don't have experimental information.

From your description, I suppose you know the random signal value (denoted by r(t)) within the time interval from 0 to T=0.01 seconds, but don't know (or, do not care) the signal value outside this interval. In order to approximate this signal as a superposition of harmonic signals, you may try the following.

1) Define a signal s(t) which is equal to r(t) within the interval from 0 to T, but is zero outside this interval.

2) Define a signal x(t) which is a sum of s(t-kT), where k is integers from minus infinity to infinity.

In this way, x(t) is an infinitely long periodic signal with its value same as the random signal r(t) within the interval from 0 to T, and, it can be expressed as a superposition of harmonic signals since x(t) is periodic.

Hope it helps. Good luck.

There are several ways to mitigate the harmonics on the HVDC converter station. However, the most common methods are:

1. Using AC harmonic filters. They create low-impedance paths to ground for specific harmonic frequencies which should be mitigated, and

2. Canceling out harmonics by using different converter configurations. Typically, 12 or 24 pulse bridges are deployed. 12 pulse bridge, for example, consists of two six-pulse bridges connected in series or parallel, with their AC connections supplied from a converter transformer that produces a 30° phase shift between the bridges.

thank you Divyansh Baranwal and Richard Lewis for your response. I will try these methods.

International treaties are binding on all parties who sign and ratify them since they are agreements between sovereign governments. Yet, depending on each nation's legal system, the process of integrating international treaties with national constitutions and laws may be complicated.

In general, there are two main ways in which international treaties can be harmonized with national constitutions and laws: through incorporation and transformation.

The process through which international treaties are immediately incorporated into domestic law is referred to as incorporation. Monist and dualist systems are both viable options for achieving this. International law is automatically absorbed into domestic law and has the same status as domestic law in monist systems. International law must be implemented through a different mechanism, such as parliamentary ratification or adoption by executive decree, in dualist regimes because it is distinct from domestic law.

Transformation refers to the process by which international treaties are translated into national law, often through the enactment of implementing legislation. This may involve adapting the content of the treaty to the legal system of the country, clarifying ambiguous provisions, and ensuring that the treaty is compatible with the country's constitution and other domestic laws.

The particular procedure for bringing international treaties into compliance with national constitutions and laws will vary depending on each nation's legal framework and the specific requirements of the relevant treaty. The relationship between international law and national law may occasionally be shaped by the courts in order to interpret and apply international treaties in domestic legal issues.

Thank you very much Joerg Fricke . Thats basically what I was searching for. If anybady have cheaper solution please feel free to share. Thank you in advance.

Initially, we need to design the circuit components and draw the circuit. You may use any software like proteus for this purpose. Then, open the simulink in matlab and select the components as it is in your circuit design. The specifications also need to be given for each component. Finally, run the design to get output.

Why would you prefer a voltage amplifier? The output voltage depends on the total capacitance (incl. connecting cable), because voltage = charge/capacitance.

Of course you can do this, but it depends on the frequency you want to measure. The voltage amplifier must have the highest possible input resistance, which is usually achieved by a JFET or MOSFET input. This is because the voltage measurement has an additional disadvantage compared to the charge amplifier: The total capacitance C of the piezo and the cable, together with the input resistance R, form a high-pass filter with a time constant T=R*C.

This means that you can only measure frequencies that are significantly above (10x) the cut-off frequency.

You can find further explanations on my website:

or

dear Matin,

don't trust formulas for modelizing the vibration of industrial structures! The reason relate to the fact that what matters are your assumptions on the "boundary conditions": formulas work perfectly for a beam in really free (or perfectly clamped) conditions, but you have nothing like that in reality...

So my recommendation is to start with EXPERIMENTAL modal analysis then try to learn how this behaviour can be approached by simple formulas if any. Then you can safer try to modelize other structures of similar construction... The same if you uses FEM. Stuctural dynamics remain an art more than a science!

I'm not sure exactly what your goal is here. My overview: if you know the tuning of the guitar (the absolute reference pitch of the lowest string and the intervals of the strings in standard tuning) you can determine the resulting pitches of any tablature depiction. I think most guitarists develop a schema or map of the neck that they learn to navigate to find specific notes and note combinations. Expert guitarists have a deeper understanding of the pitch space of the guitar neck than could be represented by tablature notation. Tablature is used primarily by guitarists who haven't developed that deeper understanding: it's a mechanical method to find particular sounds, it is not music notation in the strict sense of the word, it merely tells the player where to put their fingers, not the sounds that will be produced. Because there a single pitch can be found in several places on the neck, the topology of the guitar kind of "folds in on itself" in places, as opposed to a typical piano keyboard which is a simple low-to-high topology.

So, if you could clarify what your end goal is here, more useful comments could be made.

Referring to your final question: I think physicists and mathematicians ARE interested in music as an object, and I think musical instruments, like guitars, are objects of study. Read a few things: Hall, Donald E. Musical Acoustics, 3rd edition. Brooks/Cole, 2001; Partch, Harry, The Genesis of a Music, Da Capo Press; 2nd edition (August 22, 1979); and others for in depth explication of tuning and instrumentation. Partch is interesting because he created an intonation system and invented a whole set of instruments to play his music. You can find my masters thesis on Partch, 40 years old, here: https://www.academia.edu/84012831/Harry_Partch_And_on_the_Seventh_Day_Petals_Fell_on_Petaluma.

Anyway, perhaps I'm missing the point here. Please let me know how much I've missed the mark.

Matthew Nicholl

From what I understand, yes, the infrared bands should still be harmonized. I had the same question and was unable to find any citations for how to do this. The most recent publication I found that mentions thermal harmonization says that this harmonization is "complicated" and leaves it at that. Harmonizing surface reflectance between Landsat-7 ETM + , Landsat-8 OLI, and Sentinel-2 MSI over China | SpringerLink

However, collection 2 level 2 data should have relatively minor errors when comparing between satellites. If the higest accuracy Landsat thermal data is required for something like a timeseries analysis, the best option is to use the ARD product provided by USGS. This dataset is (currently) only available for the United States with plans for a global release at an unspecified point in the future.

Hello Hyderiqbal Sheikmohamed ,

Let me see if I understand your question. You state that you understand how the fundamental frequency, f₀, of a BPF (Band Pass Filter?) increases. You then wonder how to physically explain how the fundamental frequency gives rise to harmonics due to excitation of the system. You also seem to imply that the system has many fundamental frequencies: "these fundamental [frequencies?]"; the word 'these' is the plural of the word 'this'. Do I understand your question correctly? If I have not paraphrased your quection correctly, would you, please, restate it in a different way.

Regards,

Thomas Cuff

Shaikat Debnath , I second the comments from Sacotte Michel

1) Clearance: more related to thermal dissipation than electrical requirements. If you have a 1MW PCS with 98% efficiency, that means 20kW of power dissipation. That is a lot of heat that you should get rid somehow. If you want a very compact solution, your are probably going for water cooling, on both PCS and transformer. From a practical perspective, safety regulations may require minimum clearances for escape routes, maintenance and so on.

2) Technical issues / limitations: there are certainly technical issues. If there is or not an active front end will influence how much reactive power is required and the size of the transformer. You may want to use one secondary for each PCS, preferably with different vector groups, so that commutations do not appear on the primary side concurrently. Transformers for converters must have their core and insulation oversized compared to regular utility transformers, and shielding between primary and secondary. Regarding harmonics, take a look at IEEE 519 or the limits imposed by the utility.

60hz is the electronically service frequency in Korea.

if you change the AC to DC, eletonic noise we be loss.

AC to DC converter is well used in Car audio parts.

Is there any software or code can directly construct these dynamical matrix?

Just adding the answer myself since the resolution has been found. The best way is to make a new potential on LAMMPS.

Harmonics are generated by nonlinearity via convolution theorem.

Mohammed Lamine Mekhalfia I didn't receive an email.

Dear Amrit Tiwari :

I agree with Hiba Nadhim A. Al-Kaoaz . Harmonic response analysis simulates how a structure will respond to sinusoidally repeating dynamic loading. You can define load as a specific sin and cos function with domain and frequency to your model and harmonic analysis, but you should be done with modal analysis before that. Still, if you have a specific function for your forcing vibration, you can use it in the APDL program of your model.

regards;

Ehtisham

Hi,

Thank you so much for your response and its so helpful.

I need to know about how it works with cracks detection?

absolutely the natural frequencies of the healthy and unhealthy varies.

also amplitude of the healthy and unhealthy varies as well. I need a clear idea about detection working?

it would be helpful if someone could clarifying this..

How did you connect (RBE2 or RBE3) the bushing with the rectangular block? I guess that all DOFs of Node 4198 are suppressed. Am I right?

Where did you apply the harmonic load?

42.11

Ana María Rojas-Gómez

The answer depends significantly upon which force field you intend to use. There is no unique definition of parameters like partial charges on atom types. Each force field's developers have adopted a strategy to provide consistent definitions within their own parameterization. Thus, one cannot copy a set of Amber parameters that you found somewhere and plug them into a Charmm calculation.

Generally, creating force field parameters is a lengthy, tedious process. Developers have also documented their processes. There are, alternatively, some more user-friendly, parameter-generating codes out there but I cannot speak to their veracity or accuracy. I always used the painful, tedious approach.

Hello Amrit Tiwari ,

You have not the possibility to insert a rotational velocity in the Harmonic Response, because this kind of analysis uses mode superposition in RESPONSE to a load. The rotational velocity has its effect on the modes of the structure, then the loads from Harmonic Response are "projected" onto the structures modes and the response is than rebuilt up form each mode response.

In the Harmonic response only periodic loads are accepted (a constant acceleration is considered a periodic load with 0 frequency, therefore it is acceptable).

I suggest to perform a static structural analysis and use the pre-stressed state as input to the modal analysis (see project schematic in the annexed archive .wbpz).

Warning: the prestressed structure must have results different from zero everywhere, otherwise, there will be no difference with respect to fixed beam.

See the different response with and without rotational velocity when the prestressed state is different from zero.

Last remark: when I toggle "Coriolis effect" to on, the prestressed solution is zero everywhere, therfore the rotational velocity is completely ineffective. I don't know why, this is unexpected.

Dear Aria,

In addition to what Rezvan Marjani mentioned, You should check your equilibration.tcl script or if you're using simulation.tcl if it's not already messed up.

Alternatively, you should try and follow this tutorial. It will help you a lot.

Best regards

Thank you Hassan Nasser for your answer.

I have earlier gone through the link that you have suggested. The page shows the procedures for the direct solution of steady state dynamics analysis. However, my concern is how to divide the force magnitude (amplitude vector) in terms of real and imaginary part. I am confused, how much load I should assign for the real part and how much for the imaginary part. Please see the image given. I have given the values in "CF3" since the dynamic load is acting Z direction.

Avantes spectrometer is highly recomnded in terms of product price and benfits

you can perform easily spectral scanning.

If you are interested in photon counting and high resolution Andor is one posibility, but you should know your need for that.

Good luck,

Some places to look: https://www.llli.org/at-breast-supplementer-nursing/

https://intermountainhealthcare.org/ckr-ext/Dcmnt?ncid=520781906#:~:text=Supplementing%20at%20the%20breast%20is,from%20a%20container%20while%20feeding.

There are photos of homemade supplementers in the WHO courses on breastfeeding.

If you are writing a paper or doing research take care with the term that you use, Supplementary nursing system (SNS) is a trademarked term for the Medela product. It is not a generic term.

I don't know now if there's any other way to get a wind farm impedance scan in Simulink, but I recommend a few measurement systems located at different key points (inverter outputs) for monitoring (U, I, P, Q, S, Lambda , THD-I, THD-U etc.) and then try to analyze them according to the wind direction, temperature and humidity in that area in a certain range ...

Honestly, it depends...

It depends on the specific machinery and source mechanism.

It can be nonlinearities in the system (e.g., nonlinearities in linear drives like speakers), it can be (periodic) elements in the system (e.g. number of teeth in gears), it can be wear in components (which needs to be periodic on rotating parts, e.g. higher harmonics on railcar wheels - polygonalization), it can be impulsive behaviour triggered periodically by a rotating part (e.g. combustion impulses in internal combustion engines), it can be linearly moving parts that are not rotating (e.g. pistons), it can be some additional higher order torque components from inbalances, ...

The key point is that for all of these processes (except of some non-linearities that might generate subharmonics), you can only get integer multiples of the base period.

Nevertheless, it is important to mind the base period. For a 4-stroke engine, for example, this is 2 rotations, which is why you might also find "half orders" at internal combustion engines (and only full and half orders, no third or something...).

Hi dear Nima Rezazadeh ,

Perhaps the constant frequency component belongs to the fault harmonic force.

Best regards

Dear Emmanuel Florez Buitrago

You can add traps filters to suppress the harmonics as a series resonance circuit.

This circuit must be act as a short circuit at the intended harmonic frequency. It is also called a notch filter. Which means it must have resonance at the intended harmonic frequency. At the fundamental frequency the filter will act as an effective capacitance. So, it can be share in improving the power factor of the grid in case of inductive loads or lag phase. Otherwise it will affect the reactive power by the energy stored in this equivalent capacitance. But its value is relatively small as it is combined with an inductor to resonate at the intended harmonic frequency.

Best wishes

The command MP, defines a linear material property as a constant or a function of temperature. So I suppose you can use MP, DMPR to define constant material damping.

Also the discussion in the following link provides some useful information on this subject:

@, samar..thank alot..i will try to use your given outline in preparation of my manuscript.

Hi Bouraida El Yamouni ,

You can do this with any programming software. for example LabVIEW, Python and ... .

You just have to multiply the sine function with the desired frequency by a function with gradually increasing amplitude.

Best regards

My experience with elastomeric vibration isolators is limited by vibration control of precision instruments, that is, small vibrations (micron and sub-micron range). Hysteresis leads to dissipation of mechanical energy (damping) that can be described in terms of complex stiffness incorporating a (rather large) loss factor. In frame of this model, the dynamic reaction includes a phase shift but stays linear, described by complex transfer functions. See more in Vibration Control for Optomechanical Systems, by V.M. Ryaboy, World Scientific, 2021, ISBN 9789811237331, pages 132-137. https://www.amazon.com/Vibration-Control-Optomechanical-Systems-Vyacheslav/dp/9811237336/ ;

Also check https://gatesopenresearch.org/documents/3-1043/pdf

That's the least I could do.

Hi @Hajar Rhylane.

I would like to add a method to do this without programming using Ansys Workbench.

You may resort to solid modeling of the beam and create a body that has contact with the solid beam. The contact between the body and the solid beam should be only at one location along length at any point of time. The contact surface should be the solid beam surface and the target should be the edge of the body in contact with the solid beam. The acceleration can be applied on the body and should be adjusted to match the required contact force that has to be applied to the solid beam by contact. Hence the acceleration can be defined by a function something like a.cos(wt+phi). The type of contact can be defined as no separation contact. The linear velocity v cab be applied to the body directly.

However it has to be noted that the linear velocity v and the angular velocity w are not independent and cannot be defined arbitrarily because of the requirement that it has to arrive at the centre with the maximum amplitude. The relation between v and w can be determined by solving the two equations 1) wt1+phi = n.pi and 2) vt1= L/2. Where t1 is the time at which the body reaches the mid length of the beam. The parameter t1 can be eliminated to get the relation between w and v. The parameter n can take any whole number value.

And please remember to switch on finite sliding in the contact settings. Hope this helps.

Getting all zeros for the first 6 modes enforces the requirement of invariance of the PES with respect to translation/rotation. Harmonic frequencies obtained by finite differences may often lead, for lack of numerical precision, to non-zero values in these modes. The "purification" should consist (at least if it is the same as in GAMESS) in a procedure of transforming back and forth the matrix between cartesian and internal coordinates, which effectively helps zeroing the freqs and IR absorptions of the translational and rotational modes.

The fact that you still get those -55. and +88. cm-1 is a possible sign of your structure not being close enough to a true minimum, but I can't be sure on this. In some cases, a solution is met by simply repeating the optimisation with increased numerical precision in the DFT integration scheme and/or SCF convergence.

Arithmetic mean is calculated by adding all the sample values followed by dividing it by the number of samples taken... Geometric mean is the square root of the product of the values of each sample and harmonic mean is the reciprocal of the arithmetic mean of the reciprocal of the values of the sample... example calculation of AM, GM and HM of the values A, B and C will be

AM= (A+B+C)/3

GM= √A×B×C

HM= 3/ {(1/A)+(1/B)+(1/C)}

Arithmetic mean is used for calculation of average of anything because it consider all the observations like plant height, average speed when time is fixed, calculation of so many yield attributes. It is frequently used in agriculture and will be most authentic average... Geometric mean is used to calculate bacterial growth, cell division etc...if one value is zero, then whole GM value will be zero, because product of the value is used here..In case of harmonic mean, average of small value can be used like Average of rate or ratio because we have take reciprocal values of each samples whereby taking reciprocal of very small values obtained value is comparatively larger..

There are so many moving parts in the power system that have a lot to do with the mechanics of the system. Mitigations are there but most of them are physics related like the resistivity which is affected by the length of the wire and area then we can also look at overheating and this is because there is work done and magnetic fields hence we can control or reduce them but we can't get rid of them completely.

@abbas jamshidi Gahrouei, thanks for your response.

Dear Fidan T. Sedeeq ,

If you build your power electronic model in Matlab/Simulink then you can calculate your current and voltage waveforms. One you get these waveforms use the tool box of the fast Fourier transform to resolve the waveform into its fundamental and harmonics sinusoids provided that you have to sample the waveform with a sampling frequency greater than 2 times the highest possible harmonic frequency.

You can also measure the waveform of any experimental circuit and acquire it by using data acquisition cards then store the waveforms and analyze them using the FFT tool box.

Best wishes

I think it is important to make some restraints on the membrane to not lose the bilayer configuration when preparing the system for the simulation.

For harmonic elimination only, the concept is that your reference current is described as the difference between the measured distorted load current minus the fundamental component of the measured distorted load current.

Assuming fixed dc bus voltage this reference can be used in a conventional inverter pwm scheme with feedback to apply the necessary correction.

In this idealized case the source current should be sinusoidal.

There are several techniques in the literature to achieve this, describe above is only the concept.

See: TC Green, JH Marks great review titled Control techniques for active power filters

I think you will need to provide a better description of your ring absorber, the direction it is illuminated from, and the polarization you used, if you want an explanation.

Thanks for the answer.

I don't need to do anything special, I just want to know if there are any properties of it.

The question comes from obtaining the formula from the attached file (omega function stands for prime omega function in number theory).

I don't get your observation about the derivative though (why did you change notation?). It doesn't really use any property of the sequence h_m^(r). Unless they do, but your anwser wasn't clear enough for me.

Dear Sun, it is exactly as you say.

The way I build the system might affect results of later simulations.

Any recommendation?

Thanks

Also you may take a look at this article:

"A novel Multi-LSTM based deep learning method for islanding detection in the microgrid".

@https://www.sciencedirect.com/science/article/pii/S0378779621005551?dgcid=rss_sd_all

I totally agree with the teachers' opinions

I do not quite understand your conclusion that type-I phase matching will give rise to a delay between fundamental and SHG as both pulses travel at identical phase velocities in the crystal. Of course, this does not mean that group velocities are identical, too, but as the SHG becomes most intense during the final stretch of the propagation I would not expect much of a measurable delay from that effect.

You can theoretically investigate this by setting up the coupled propagation equations for fundamental and SHG, including a group velocity mismatch. If you want to measure this then you can certainly try to set up an auto/cross correlator with a broadband nonlinearity, e.g., tightly focusing on a quartz substrate using surface SHG/SFG. However, you would unavoidably see dispersive effects due to beam splitters, lenses and air paths rather than the delay incurred during the original SHG process. There are ways around this, but this would be a rather challenging experiment for an effect that probably does not even exist.

Israel Zadok thank you so much sir. Much appreciated.

I investigated the Calanoid Copepod Centropagidae fauna of some 650 Tasmanian (Australian) subalpine lake and wetland systems and found that there were 3 distinct geographical provinces base on distribution of species. IS this of any use to you ?