Axial Stiffness Augmentation by Adding Superconductor Bulks or Limiting Permanent Magnet Rings to a Horizontal Axis Zero-Field Cooled High-Tc Radial Passive Superconducting Bearing

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This was an interesting paper on the magnetic levitation of an axis using superconducting materials and permanent magnets.

Reading the paper, several questions arose.　Can you add a brief explanation to the paper?

 

(1) Can't HTS be made into a ring instead of using multiple rectangles?

(2) How is liquid nitrogen circulated through the HTS to cool it?

(3) What is the basic concept of this HTS and permanent magnet arrangement?

4) What are the shaft's gravity, axial, and radial stiffnesses?

5) What are the applications of the applied magnetic levitation system?　Are there any design targets?

Author Response

Please find attached the authors' coverletter answering to the comments and suggestions made by Reviewer 1.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

I think that the paper is quite interesting and experiments are well described. My remarks are mainly in a batter introduction examining the needs, the application, the margins if improvement, in the right sequence, rather than parachuting the reader in the middle of the discussion.

 

This work is very interesting and provides direct insight in the performance of suspension bearings using magnetic repulsion. Unfortunately I have some remarks in the following, mostly on the Introduction and the clarification of the context and application.

 

1) The Introduction fails to achieve its first and foremost objective, namely "introducing":
- why the problem is important and which advantages the area of research ensures?
- are there negative aspects, or disadvantages?
- what are the applications?
- what are the previous studies and where they can be improved? why the proposed is relevant?
The overview seems synthesized in the lines 38-41, that is a bit hermetic and the first impression is that the reader is thrown into the discussion... only after 1 page at lines 63-78 there is another part of the discussion.
So, it's better to rearrange and organize introducing the points above, so that the reader can absorb gradually from a high-level overview to the details of the previous studies and techniques.

2) The acronyms must be introduced the first time, but also explained: maybe a high-temperature semiconductor is known, but not the meaning of zero-field cooled. Liquid nitrogen (LN2) should be also introduced. 

3) Line 114. The expression "after the ZFC of HTS bulks" is not clear.

4) Please note that the letters to describe the topologies are skewed and do not correspond to the letters indicating the insets of Figure 3. After careful reading it is understood but it is quite inconvenient.

5) The overall discussion of Section 2 is clear and choices are well justified.

6) Figure 10 is not clear: it seems a low-resolution version of another figure and it is black and white, so all curves look similar; please, do it in color.
Similarly Figure 11, that would be much easier to understand if drawn in color.

7) Pay attention that at line 274 you wrote "topologies G, E or G".

8) One aspect that is not discussed is the influence of the various geometries on the amount of generated heat and on the heat exchange efficiency.

 

9) Pay attention that the level of self citation is quite high, being 8 out of 23.

Comments on the Quality of English Language

Minor English issues, like some missing article, some sentences that are difficult to read or parts a bit hanging. Overall is quite good.

Author Response

Please find attached the authors' coverletter answering to the comments and suggestions made by Reviewer 2.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,

thank you for your kind explanations and the extensive amendments to the paper.

I have no other remarks.

Author Response

The authors feel well, by answering to the comments and sugestions of Reviewer 2, and that there are no other remarks from this reviewer.