Temperature Dependence of Normalized Sensitivity of Love Wave Sensor of Unidirectional Carbon Fiber Epoxy Composite on Mn-Doped 0.24PIN-0.46PMN-0.30PT Single Crystal Substrate

Round 1

Reviewer 1 Report

This article deals with Love sensor which are very attractive acoustic sensors for gas or liquid detection due their high gravimetric sensitivity. The choices of the materials (piezoelectric substrate and waveguides) and their dimensions must be chosen in order to achieve the highest sensitivity to the mass effect. Ageing effect or influences of parameters such as viscosity or temperature have also to be taken into account. Various piezoelectric substrates (quartz, PMN-PT, etc) and dielectric materials (rigid layers or polymers) can be used as waveguides.

The paper proposes theoretical calculations on Temperature Coefficient of Frequency (TCF) and gravimetric sensitivities for a Love wave sensor for a configuration based on a single crystal piezoelectric substrate (PIN-PMN-PT) with a carbon fiber epoxy composite wave guide.  All results and discussion are very well presented. Temperature dependence of elastic parameters (C44 for wave guide or C44 and C66 for the piezoelectric substrate) are shown to influence the sensitivity. The carbon fiber orientation has to be considered as well as an optimum design (h/l) which proposed to minimize temperature effect while optimizing gravimetric sensitivity. Higher sensitivities than those of classical Love sensors based on fuse quartz/quartz are expected. The team also improved previous sensitivity results obtained with CFEC by replacing the piezoelectric substrate (CFEC/PZN-PT for previous results in reference 37 in this paper). Note that the fact to adopt a unidirectional CFEC waveguide layer with the fibers parallel to the direction of the propagation of the acoustic wave was already proved in a previous team’s paper.

Nevertheless, even if we have to be aware that the “sensitivity” to temperature of such devices responses is well known, the fact that such temperature variations could be eliminated by using a dual setup with a reference delay line should be noted. This information should be indicated in the introduction or conclusion? We also can regret that experimental validation are not shown to validate the theoretical calculations, and the relevance of geometries and material choices.

 

The problems/suggestions are as follow :

SUMMARY:

First, the summary is not always clear and should be rewritten to put in evidence the fact that all results are theoretical results.

CFEC acronym should be defined in the beginning of the summary. The fact that you are dealing with gravimetric sensitivity should be indicated here and throughout the manuscript or at least in the introduction. The sentence “however the piezoelectric substrate has constrating property” is to my opinion confusing.

Finally, you are referring to the C44 elastic constant of the waveguide that should be low. I also suggest to highlight the role of the C44 and C66 substrate coefficients.

 

INTRODUCTION :

I suggest to indicate the sign of the TCF for litterature results (sign “ +” when it is positive).

Line 54, the type of sensitivity should be clarified, in this case gravimetric.

Line 110 “this paper reports on characterization…” The term "characterization" misleads the reader as the paper is only on the theoretical part. Please correct it.

CONCLUSION :

What about the perspectives of this work? In the introduction or conclusion, the fact that such temperature variations could be eliminated by using a dual setup with a reference delay line should be said.

DISCUSSION

Figure 1: As the CFEC are unidirectional, I suggest that this peculiarity of the guiding layer should appear on the drawing.

Figure x is “redondante” with the graph. I am not sure it is necessary…

As shown for instance in reference 22, a table comparing TCF and gravimetric sensitivity (experimental and/or theoritical values) could help the reader for an easy comparison. This could also highlight the sensitivity improvement of such configuration.

The formula (1) looks to have a typoThe sum between the 3 terms doesn’t appear on the formula. Please, in formula (1) define the v phase velocity, it does’t appear in the manuscript, it should be defined for this first formula and its name should appear on the y axis (figure 2 for instance)

In the formula (2), you have chosen to use notation F for the frequency, I suggest to keep a small letter f as it is usually used for formula using frequency f.

Table 1 : in case of the fiber orientation along the y -axis, where does the material constants are coming form?

Table 3 is not necessary as the results are clearly depicted on figure 6

Author Response

Response to Reviewer 1 Comments

Manuscript number:  #applsci-991332

Title:  " Temperature dependence of normalized sensitivity of Love wave sensor of unidirectional carbon fiber epoxy composite on Mn-doped 0.24PIN-0.46PMN-0.30PT single crystal substrate "

Correspondence Author: Naixing Huang

Dear Ms. Aria Tang and Reviewers,

   Thank you for your letter and for the reviewers’ comments concerning our manuscript. Those comments are very helpful for revising and improving our paper.

We have made correction which we hope meet with approval. We revised the paper with MS Word revision mode. English language of the manuscript has been edited by Editage. Response to Reviewers’ Comments are in the attachment.

Special thanks to you for your good comments.

We hope that these revisions are satisfactory and that the revised version will be acceptable for publication in the journal “Applied Sciences”. Thank you very much for all your help and looking forward to hearing from you soon.

Wish you all the best!

Sincerely yours,

Naixing Huang

Author Response File: Author Response.pdf

Reviewer 2 Report

Abstract:
L23/24: "Optimmum device design", the design of a sensor needs more parameter so the terms should be changed
L25: CFEC should explain there
L32: "from the device in the CFEC/Mn" with which CF axis?
L35: "thermo-elastic stability", why?

Introduction:
L41: "and" should be replace by "where"
L112: Why did you choose this range of temperature?

Results and discussion
L159: "C44 and C55... is the immediate cause". Sure because these two parameters are the only parameters used in your simulation.
L163: "30...55°C", principal elastic contants at these temperature and orientation should be added in Appendix.
L182-183: You say that a Love wave sensor is always expected to have the highest sensitivity. Yes but to what: temperature, mass, viscosity, ...
Fig.2 & 3: Fixe the denomination to M1, M2,.. or First ordre mode, second,.... But not both
L196: "employing two first ordre modes" it's confusing! You only use M1 for figure 3 a) & b) and not M1 & M2.
L200: If one parameter is fixed, it's sure that the other one fixe the variation. I don't understand the usefulness of this sentence.
Fig.6: Why did you stop your simulation at these values of h/lambda?
L257: "cannot increased unboundedly". Yes for sure but could you explain the reason to stop there? Is it due to your comparison with fused quartz/ST quartz? If so you need to add its TCF value too and not only its sensitivity.

Conclusion:
You always compare with fused quartz/ST-Quartz but you must say that you compare mass sensitivity.
What about the other parameters that must be take into account for a sensor? It really depends on the application

 

 

Author Response

Response to Reviewer 2 Comments

Manuscript number:  #applsci-991332

Title:  " Temperature dependence of normalized sensitivity of Love wave sensor of unidirectional carbon fiber epoxy composite on Mn-doped 0.24PIN-0.46PMN-0.30PT single crystal substrate "

Correspondence Author: Naixing Huang

Dear Ms. Aria Tang and Reviewers,

   Thank you for your letter and for the reviewers’ comments concerning our manuscript. Those comments are very helpful for revising and improving our paper.

We have made correction which we hope meet with approval. We revised the paper with MS Word revision mode. English language of the manuscript has been edited by Editage. Response to Reviewers’ Comments are in the attachment.

Special thanks to you for your good comments.

We hope that these revisions are satisfactory and that the revised version will be acceptable for publication in the journal “Applied Sciences”. Thank you very much for all your help and looking forward to hearing from you soon.

Wish you all the best!

Sincerely yours,

Naixing Huang

Author Response File: Author Response.pdf

Reviewer 3 Report

Dear authors,

The manuscript is well written and is suitable for publication.

Best regards,

Author Response

Response to Reviewer 3 Comments

Manuscript number:  #applsci-991332

Title:  " Temperature dependence of normalized sensitivity of Love wave sensor of unidirectional carbon fiber epoxy composite on Mn-doped 0.24PIN-0.46PMN-0.30PT single crystal substrate "

Correspondence Author: Naixing Huang

Dear Ms. Aria Tang and Reviewers,

   Thank you for your letter and for the reviewers’ comments concerning our manuscript. Those comments are very helpful for revising and improving our paper.

We have made correction which we hope meet with approval. We revised the paper with MS Word revision mode. English language of the manuscript has been edited by Editage. Response to Reviewers’ Comments are in the attachment.

Special thanks to you for your good comments.

We hope that these revisions are satisfactory and that the revised version will be acceptable for publication in the journal “Applied Sciences”. Thank you very much for all your help and looking forward to hearing from you soon.

Wish you all the best!

Sincerely yours,

Naixing Huang

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

I agree with this new version.