EMI - Science topic

Junwei Liao Investigating lecturers' perceptions of English Medium Instruction (EMI) may be a fruitful research subject since it can give insight into the experiences and perspectives of the instructors in charge of providing EMI in higher education settings. In particular, as the use of English as a medium of instruction has increased in China in recent years, researching lecturers' opinions of EMI can aid in understanding the obstacles and possibilities connected with this transition in language use.

The study might be valuable for Chinese educators and administrators involved in the implementation of EMI in higher education. It can, for example, aid in identifying areas where lecturers are confident and well-prepared, as well as places where they may want more assistance.

It can also reveal how lecturers are adjusting to the use of English as a medium of instruction, as well as the impact this change is having on their teaching and students' learning.

Furthermore, the research can benefit institutions by giving feedback on the EMI policy, the amount of teacher training, and support. It can also benefit policymakers because the study can assist to guide the development of EMI policies and strategies in higher education.

Overall, researching lecturers' impressions of EMI in China may be a significant study topic since it can give insight into the experiences and perspectives of the instructors who are in charge of teaching EMI and assist to understand the difficulties and opportunities.

Q can be easily converted into apparent conductivity by a simple multiplication if the the instrument is working at very low induction numbers B which is defined by the ratio between coil separation (s) and the skin depth, i.e., it is valid when s is very small in relation to the skin depth which is inversily proportional to the conductivity. Of course this formula applies only to homogeneous media or layered earth. when the subsurface has heterogenities it fails, e.g., can lead to negative conductivities...

Unfortunately I did not work with EM38-MK2...

If you want to take a look at my PhD thesis maybe it could help you... it is avaialable here in research gate.

For EMI shielding, it is important to not just look at the absolute value, but to also consider the thickness of the material. For EMI shielding materials, the higher the conductivity, the better the EMI shielding ends up being (in most cases!) Generally, what we've observed for MXenes (M_n+1X_nT_x) are that their EMI shielding efficiency also depends on the conductivity of the MXene. To date, the highest conductivity reported for a MXene is Ti₃C₂T_x which has values above 20,000 S/cm ( )

Considering this, Ti₃C₂T_x appears to be the best MXene for EMI shielding. However, there was a recent article published in Science ( ) that shows that annealed Ti₃CNT_x has a higher EMI shielding value at the same thickness. This means that there is some fundamentally different mechanism that is occurring with Ti₃CNT_x over Ti₃C₂T_x.

Now, to further add some information, all MXenes will have EMI shielding capabilities, but at different amounts. In this article, 15+ MXenes were tested using a uniform methodology ( ). What we found is that generally MXenes will follow the correlation between conductivity and EMI shielding efficacy. However, some MXenes show significantly higher EMI shielding efficiency than is expected based on their conductivity, meaning that there is some other physics happening that we currently cannot explain.

in addition to what has been mentioned already (Rf loads) : anechoic chambers;

filters are often of reflective type (i.e. reflect the incoming power outside the passband); and of course stealth technology..

does the shoulder appear in the total energy peak in the HPGe gamma spectrum of certain samples, there are two probabilities, if the problem in the HPGE detector, adjust it if not it is problem due to the high activity of the sample therefore it is necessary to remove the sample at the level of the detector to eliminate the peak sum phonomene

You could also try seacrhing on iris-database.org.

e.g.

Hi,

The following article can be helpful.

Regards

Dear Shoaib Aasim, aniline polymerizes via oxidative polymerization, using strong oxidants such as APS and the acids you mentionned. Please check the following document. My Regards

https://www.nature.com/articles/pj201143#:~:text=The%20conventional%20chemical%20oxidative%20polymerization,as%20ammonium%20peroxydisulfate%2C%20APS).

I give two references that will help you.

You can look at Rohde & Schwarz application note RAC-0607-0019_1_5E.pdf available from their website. You can also check Keysight Product Brochure 5991-2171.pdf that lists additional literature.

Happy reading :)

To see some voltage in the port of the probe (in the spectrum analyzer), time-varying magnetic fields must penetrate the loop surface of the probe (i.e. the time derivative of the magnetic flux through the loop surface must be non-zero); so the best orientation of the magnetic probe on a PCB track is as shown in the picture attached.

(the picture is from https://www.langer-emv.de/en/category/near-field-probes/19)

Dear Mr. Ali,

there are many good shielding polymer concepts.

So it is not the best way to use Slygard 184 PDMS.

A good way is to use a polymer with very good intrinsic

particles ( MWNT or CNT or ... ).

Yours Sincerely

F. Gräbner

Another update, Stefanie Mayer

We have rebranded to ExpiWell (www.expiwell.com) which has more than 2,100 researchers on the platform. You can easily implement EMA/EMIs on ExpiWell as we have key features that are helpful:

1. Ensuring time zone matching for participants (e.g., 8am is 8am regardless of timezone)

2. Enabling personalization of timings for participants (for lessons/activities/assessments)

3. Participant log to track response rates and message low response rate participants

4. Participants can view charts of their (formative) assessments (if enabled)

5. You can capture multimedia and location data

6. GDPR enabled

7. Payments can be made through the ExpiWell system

We are also partnering with several key organizations and institutions on EMAs/EMIs too and building out more features.

A few thoughts which you may find relevant here:

Although globalized English is a recognized phenomenon in the researchers' circle, it is yet to make its vivid presence in the language classroom neither in the outer or expanding circles. Perhaps you may wish to address the research debate among researchers concerning the role of English as an international lingua franca in international universities. I highly recommend Jenkin's outstanding contributions (2002,2005,2006,2014) in the field as well as the work of Canagarajah; Kachru; Graddol; and Seidlhofer; among others.

Good afternoon, colleague!

Dear Nicola,

I am the head of Foreign Languages Department, South Ural State University, Russian Federation. I am deeply interested in the topic of EMI implementation and EMI teacher training. I would be happy to collaborate with you on the topic of EMI implementation and extend your research to the Russian Federation as much has been in Russia in the field of EMI implementation though it is not still visible on the global map of internationalization.

Why don't you try the same using FORTRAN/C/C++/MATLAB etc numerical software. Excel is good for office work, not for research.

I would suspect, as I think you do, that you will find affective strategies for both content and language. Perhaps then, your task could be to include the relevant literature from both fields with a view to 'closing the gap' by synthesising them for an 'emerging' field of EMI research. That doesn't, I'm afraid, lighten you workload, but ...

Tony Maine Thank you very much for your suggestion. The advantage of using FMLF is that filtering inductance and capacitance can be integrated into the same unit. Therefore, the winding of L and N wires on the core is closely connected, just separated by a dielectric layer. It seems difficult to alleviate parasitic issue. Especially for CM inductor, the winding distance between L and N wires should not be too large, otherwise, the CM coefficient will be decreased. In addition, the volume and weight of inductor should be considered comprehensively.

Now, I am trying to balance the requirements of inductance and capacitance based on meeting the requirements, find out the optimum structure and size of magnetic core as well as the size and layer-number of FMLFs, minimizing the number of winding turns, Thx for your answer again.

Thanks Rafia Raees.

You need to replace the lowpass filter which follows your detector with an integrator, with the correct attack, decay and integration times.

Post processing would imply doing a convolution with the characteristics of such an integrator, which would be messy.

Dear Sassia,

In my opinion and although they are related, pulsed signals cannot be directly compared to switching EMI.

It can be said that Switching EMI is a product of pulsed signals and it is caused by the fast rising/falling switching edges of pulsed (switched) signals.

The reason is that fast switching edges cause high frequency ringing (oscillations) due to the parasitic inductance and capacitance in a circuit. That high frequency ringing couples to the various wires/tracks of the circuit and is emitted, either as radiated emissions or conducted emissions.

It can be done both ways. At times English is self sufficient or at times mother tongue will contribute to more details. It actually depends on the personnel to whom you have floated the questionnaire and the place he is serving in the hierarchy of the organization.

Prasanna Waichal, thanks for your answers !

I'll be glad to share the results.

Check this website

https://www.teachingenglish.org.uk/article/medium-instruction

Dear gajanan,

Hope you are doing well. you can use IEEE Xpolar Digital Library to research about the recent publications in EMI/EMC. i think the attached link can help you.

Regards.

Thomas

The data is from an HP vector network analyser - it is the standard format and I recognise the header - I work with these all the time. The data looks like it might be for something using x-band waveguide - it transmits above about 7 GHz, and is cut-off below.

English Medium Instruction or English as a Medium of Intruction (basically teaching through English)

Dear Mr. Kingsley Ajekwene,

no, the EMI SE effect of a bulk material is only a effect of the electromagnetic

intrinsic values.

Onyl one product have a mechanical problem with the mechanical strength.

This is a gascet.

In the dependence of the mechanical pressure we have a change of the shielding effect.

Sincerely Yours

F. Gräbner

Hi Nathalie,

working through pages 10 to 12 of the following paper seems to provide the answer to the question why VPE doesn't have a switching frequency component during bipolar switching:

I still did not complete the reading myself but by providing the link I intend to give you the chance to overtake my slow reading. ;-)

Hope this helps.

Dear Pouyan,

The inductive interference caused by ac electric traction lines to nearby telecommunication cables has been investigated in this paper: K. J. Satsios, D. P. Labridis and P. S. Dokopoulos, "Inductive interference caused to telecommunication cables by nearby AC electric traction lines. Measurements and FEM calculations," in IEEE Transactions on Power Delivery, vol. 14, no. 2, pp. 588-594, April 1999. In this article there is useful conclusions concerning the influence of the separation distance between the electric traction line and the

telecommunication cable, of the earth resistivity and of the mitigation wires on the inductive interference levels have been obtained, by using a FEM parametric study.

Other important references:

International Telecommilnication Union : "Directives Concerning the Protection of Telecommunication Lines against Harmful Effects from Electric Power and Electrified Railway Lines", vol. I and vol. 11, Geneva 1989.

J. R. Abbott, "HVDC System Simplified Method of Harmonic Coupling Calculation and Testing", /IEEE Transactions on Power Delivery, PWRD-3, April 1988, pp. 839-844.

In fact, I am not quite familiar with other ways of undrstanding EMI, or even it the way it appeared to me is shared by others. Since I am in TEFL field of research, curriculum studies in particular, my actual concerns regards the implications of these policies which are spreading around from goverment to universities here in Brazil. Really, I do worry about the ideology behind Proposition 227. I do not quite agree with it. As well as I have been struggling to forsee what kind of benefits and with what purposes EMI is being thought of to our English language learners in Brazilian universities.

Faraday tent replaces hermits, solitude in modern conditions. Faraday came up with a simple device to protect against electromagnetic waves of any range. This was necessary for precision work of a certain subject without electromagnetic interference from outside. By the way, before it was enough to retire to a remote village and remain alone with nature. Currently, the Internet and mobile communication network surrounds from all sides even on Mount Everest. There are two main problems of this situation. Humanity does not know whether the pathological contribution makes a permanent electromagnetic effect exceeding the natural background, in the development of such pathological processes as cancer, epileptic status, changes in immunity, fatigue? But there is scientific evidence that the pathological component of increased electromagnetic interference is present. So, the saying that "with a nice person paradise and in a hut" has a weak relation to the tent Faraday. All his life in the tent of Faraday will not live as Diogenes lived in a barrel. It is advisable to unite talented scientists to solve this problem for the future Human.

Hi Marvin

I intend to prepare a shielding material

Thanks

Very roughly: you can routinely achieve shielding effectiveness of about 20-30 dB wih carbon based fillers (carbon black, graphite, carbon nanotube and their combinations) but that is not too much. 30-40-50 dB can be achiwved with metal-coated glass or carbon fibers or with stainless steel fibers which is almost aceptable. 60-70 dB can be achieved with high quality electroless plating on plastics, which is excellent.

The coupled inductor reduces per-phase current ripple that means smaller losses and/or smaller per phase inductance, the output/input current ripple it does not reduce but as it is multiphase structure with interleaved currents the output/input ripple is small. The main drawback is that fast current control loop in each phase is required to prevent saturation of coupled inductors.

Great question thanks

thanks

How effective is the learning beneffit to bilingual students and what are the assessment metrics. Perhas looking at French-English while conducting a parallel correlation studies.

Hello,

the greeen cable goes to the same spot as the socket.

The freely laying plug is from the second oil pump used for VP mode. 

//UPDATE

i tried to image the sample (gold on carbon) as close to the lens as possible (WD circa 3 mm) and also some TEM grid being literally inside the lens (WD 0.5 mm) and the problem still perists. So does this mean it is a vibration?

There is not a simple answer for that  question.

PMSG are expensive compared to other technologies. Brusless Doubly fed generatorsusually have lower power densities (than regular DFIGs) and this could increse the head mass.in the wind turbine. Cage induction generators have less efficiency and cannot operate at low speed.  

An assessment of conducted emissions can be done using Spice. This is comparatively easy - it can be done with abstracted building blocks of your circuit modeled as voltage sources.

Simulating radiated emissions requires the reproduction of your actual physical circuit. For this I have no recommendation.

We are dealing with very low magnetic fields for Spacecraft on Science missions. Very low means here an order of magnitude of a few nT, far below the Earth magnetic field. Examples for such science missions are SolarOrbiter, JUICE and BepiColombo. We have to perform a magnetic cleanliness programme, starting with the selection of non magnettic materials, magnetically characterize important components and boxes and put the sensitive instruments on a boom in order to gain some distance to the magnetic sources on board the satellite.

Thank you, Vadim. Yes, let us for the sake of simplicity, consider the pair of "transmitter" and "receiver". Of course, there is a "channel" with these or those properties, where interferences pass and interact. This PhD thesis can serve as a good starting point for modelling the on-chip EMI 

E. Backenius, "Reduction of Substrate Noise in Mixed-Signal Circuits," 2007

today, many papers focus on EMI modelling. so EMI issue of each systems can be predict and simulate. so EMI issue can be studied easily without measurement setups.

an example of EMI modelling can be find in attached file.

Best regard 

To enhance the skills of students (and teachers as well) in English speaking, we established English Speaking Zones, where students and teachers should talk or speak in pure English and penalties are imposed on those who were heard speaking in the native language.

Dear Lady,

of course we have unwanted effects. We have the resonances in the Farraday shielded box. It is important, that you know the geometry and the mode and the source frequency, so you can calculate the resonance frequency. In this resonance frequency the shielding have lower values. This is bad.

All the best

F. Gräbner

Thank you very much for your comment, Prof. Donggyu Jang. We've seen this pair if double-shield cables called starquad, which minimizes the EMI noise. The residual noise passing through the shield is compensated since it is detected equally by each cable of each pair:

It may be more useful for your needs.

Regards

Thanks to all of you for share nice your concept

Dear Fernando,

I met with this problem in archaeological prospection (magnetic prospecting - see attached file). From the personal communications with Engin. Faculty scientists follows that they have a solution for ideal sourse, but in real conditions (not horizontal cable location, rugged terrain relief, some other noising factors), they receive abn accuracy of calculations about 20-25%.

Best

Lev

Dear Mr. Mannepuli,

this is not a EMC tester. This is only a optical tester of a optical filter.

All the best

F. Gräbner

Dear Martin, Dear Sujit,

The coaxial shunts are indeed better, but still a common mode current can appearas they are linked to the circuit and mass currents flow trough the circuit, so still a common mode current appears, generating inductive drops elsewhere in the circuit. So it is sometimes better to use a normal shunt with 20nH and 10mohm giving a time constant of 2µs and to compensate that time constant with a 2µs low pass close to the place where you need it. However, all of these methods are invasive in the circuit.

If no precision is needed but just to compare a converter with another identical one, the following trick can be used. This is using a  small SMD inductor (wound I-core) to sense the near field. The smd inductor should be capacitively screened (coax) and loaded with a damping resistor (to avoid resonances with the capacitance of the probe coax). It mainly senses di/dt, but I tried it and one can distinguish also resonances in the drain current and also in the gate current. The advantage is that it is non-contact (no mass current) and non invasive. One still can recognise the duty ratio and even some aspects of parasitic resonances in the supply, or just compare signatures in a qualitative way. However I don't think of using it yet for a reliable current-feedback.

You can use Hyperspy:

It is a free, open-source software for advanced data analysis. It runs in both Windows and Linux, it can perform statistical analysis in your data (like PCA) and also many features specific for EDS are available.

Hallo Mr. Sain,

an intersting method to measure the shielding of a material is the german VG ( military ) standard.

Yours Sincerely

F. Gräbner

thanks sir for the response... the paper that i have attached have the brief of ports placement and the response of simulation... other than that I have made the same design in HFSS 13.0, that .hfss file is attached with this reply.... please check the boundary conditions and coax ports that i have made....

Ensure that no part of any antenna is closer than 1 meter from the walls and 0.5 -0.7 meter from the ceiling of the shielded enclosure. Check these condition with max dimension of the antenna(i.e.,there r so many antennas we may use for testing, so while designing keep in mind the max dimension of antenna which u may use )

Depending of geometry, materials, field sources and frequency range, results of interest, you have three fundamental options: FEM, BEM/MoM/IEM (including their combination) and FDTD/FIT, but sometimes PEEC or TLM may give better results. Electromagnetic modeling is an art. There are no definitive recipes. The most popular isn't always the best approach. You should compare the advantages and drawbacks of these method, in order to choose the best approach, appropriate for your problem. But first of all, understand deeply your problem and (re)formulate it in correct manner. Do not expect valuable answers to vaguely formulated questions.

the mat lab has a FTP tool which will help u to sort out u r problem of calculation.

Thanks a lot Eng. Kenneth for your reply. One of the problems of that solution is that the dynamometer has its own radaited emissions as can be seen in Figure 2 in this article http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6050737 !

Thanks Marco for your reply. The problem of using a semi-anechoic chamber provided with a chassis dynamometer is that this type of equipment has its own radiated emissions that will of course interfere with the EMI disturbances due to the vehicle. For more information about this point, I recommend this article: Silva, F.; Aragon, M.; , "Electromagnetic interferences from electric/hybrid vehicles," General Assembly and Scientific Symposium, 2011 XXXth URSI , vol., no., pp.1-4, 13-20 Aug. 2011

Good luck.

These shielding effect should be caused by the strong conductivity of carbon fibers themselves, that in turn squeezes EM field on UAV surface, limitating the signal power in arriving to antennas. May you check for different solutions:

1) increase the sensitivity of your antenna, inserting a signal amplifier;

2) transport the antenna outside the body of UAV;

3) put different antennas in all of 4 internal sides of UAV, possibly in direction where there aren't composited parts.