Tribological Properties of Two Typical Materials of Hydraulic Motor’s Rotor at Different Ambient Temperatures
Round 1
Reviewer 1 Report
In order for the article to be better perceived by the readers, several improvements can be made.
The literary review is quite well and fully done. When describing some sources (for example, 11, 12), it is simply indicated that the researchers have been considered some questions. But there are no comments about results of the studies. It would be good to explain it.
In the “Materials and methods” section in Fig. 1b it would be good to specify a scale ruler so that you can estimate the dimensions of the product. Also, please, add a ruler in Figure 7a, 8.
It is advisable to describe in more detail the methodology of the conducted research, especially this questions:
How was the roughness measured and on what equipment?
How was the temperature measured and controlled during the tests?
Were standard Sharpie samples used for impact strength tests?
Specify the manufacturers of the specified equipment (microscope, ferrography analyzer, etc.) and the country.
In section 3.1. you provide information about the impact strength tests. At the same time, you do not specify a confidence interval on the charts. It would be good to specify a confidence interval for Figure 6. And this is very important, because the spread of values in such tests can be very significant. Also, in the “Materials and methods” section it is necessary to specify how many samples were tested at one point.
You write that “the brittle-ductile transition temperature of QT500-7 ranges from -20°C to -30°C” (line 215). But Figure 5 shows that a sharp drop in impact strength occurs in the range -10-20 ° C. You write the same thing on line 252 in the “Discussion” section, but graph 5 shows otherwise. In the range -10-20, the drop in impact strength according to the schedule is ~55 units, for the range -20-30 ° C, the drop is only ~ 25 units. It is clear that this interval is in good agreement with the data in Figure 8, but questions arise about the validity of these statements. This is also transferred to the “Discussion” section (line 352), although this is not obvious according to Figure 5.
On graphs 5, 6, 8, equidistant points are used. But the temperature values you have are 25°C, 0°C, -10°C, -20°C. Even for columns, it would be nice to use a real scale. And for graphs of friction coefficient values, it is mandatory to use a real scale. Also, why didn't they take a single temperature change step of 10°C? The rationale for choosing such a range must be given in the “Materials and methods” section.
Conclusion №1 is well-known and it needs to be stated with specific results.
Conclusion №3. You write about mechanical properties. But in the article you studied only the impact strength. On what basis do you write about other mechanical properties? It is worth specifying only what is researched in the article.
In general, in the “Conclusion” section authors should be work out the accuracy of the wording.
At the end of the “Introduction” section, it is necessary to set the objectives and goals of the study and briefly describe the work plan. Then the reader will understand why mechanical tests are being done, and why after that tribotechnical tests are performed.
Author Response
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Reviewer 2 Report
Reviewer Comments
In this paper, the reliability of hydraulic motors is essential for polar ship open-deck machinery. As 10 cold starting is the biggest challenge for mechanical equipment in polar environments, changes in 11 material mechanical properties and lubricating oil physical and chemical properties are the main 12 reasons for abnormal wear and shortened lifetime of equipment. This study started with measuring 13 the viscosity of hydraulic oil and the material mechanical parameters via viscometer and mechanical 14 bench. Then it analyzed the tribological properties of the two typical materials of hydraulic motor’s 15 rotor at different ambient temperatures, especially at low temperature. Finally, it explored the wear 16 process and mechanism of two sets of friction pairs. The results showed that every test result of the 17 QT500-7 test ground was worse when the material was exposed to -20°C, indicating that the impact 18 energy of the material affected its tribological properties since the impact energy of material QT500-19 7 decreases sharply at the temperature.. However, the followings should be carefully addressed in the revision to be published in Journal of Applied Sciences.
1- The authors should be followed the instruction of the Journal Applied Sciences parts and sections in this manuscript.
2- Complete mathematic calculation model with all nomenclature missing
3- The abstract needs more quantitative results. The abstract section is an important and powerful representation of the research. It is better that the results should be presented with the support of specified data. Please provide your contribution and work novelty.
4- The authors should indicate this technique to enhance system performance. Also, the author should add more references that discuss the effect of using this technique. It is recommended that the authors carry out wide analysis and comparison with the state-of-the-art studies.
5- Most tables and figures are highly needed improve the quality of all tables and figures.
6- Add references for all equations.
7- I would also expect to validate with two more experimental works available in the literature.
8- The literature review must be improved. Please highlight in the literature review the differences between previous papers and your paper. Please clearly indicate the knowledge gap and prove that it is a really not analyzed area of the field. Please indicate new approach / new methods in a comparison to the existing investigations (literature review should be extended).
9- Description of Experimental Methods of tribological propertiesanalysis should be improved. More quantitative information about the grid selection (which method was used.
10- You need to add error analysis of your results and add the error bars in your graphs to indicate your accuracy measurements.
11- Improve work justification.
12- More quantitative conclusions should be presented. Please prepare additional comparisons, some percentage differences. There is a lack of quantitative conclusions which should contain main findings from the paper and highlight the new and high novelty and contribution of your work to the field.
13- Present the mathematical equation of the boundary conditions and initial condition.
14- I would also suggest including in the conclusion section but also in several other places in the manuscript discussion and comparison with findings from other authors with similar published research work.
15- The conclusion section on lacks in summative conclusions. The main results, novelty and academic contributions should be emphasized in this section. Moreover, are the results obtained in this paper really applicable in other similar researches?
16- In the discussion development, it is very important to emphasize points of agreement or disagreement between results in this work and others cited in references part of manuscript.
17- Authors should discuss limitations of the current study and possible improvements for future directions/research works.
18- Finally, I recommend the author to read through the whole text and correct it to make it more reader-friendly.
Author Response
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Reviewer 3 Report
This manuscript is about invesgitation of tribological Properties of 2 commonly used materials for hydraulic motor’s rotor operated at several ambient temperatures. The approach combines basic theory but with thorough emxperimental investigation and data analysis aiming at understanding reliability of the hydraulic motors. The work is well presented and the results support the conclusion remarks. This work can be acceptable for publication in this journal shuold the following minor points be improved.
(1) Quality of Figure 7 needs much improvement.
(2) The subplot labelings in Figure 9 do not aggree with that in the caption. That is only (a) and (b) are shown in the legend but there are a-1, a-2, a-3, b-1, b-2, b-3. Same is for Figure 10 and Figure 11.
(3) In general, this is a very good experimental investigation in which the conclusions are supported by experiments. However, it is not clear what is the major contributions of the work to research community and what are the obserced tribological properties of the rotor to the mortor's reliability?
Author Response
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Round 2
Reviewer 1 Report
In general, the article has become much better. The authors have done quite a lot of work. Fixed a bug with a range of -10-20 degrees, revised conclusions.
But still, those answers that the authors gave me on the methods should have been added to the methodology section (about Sharpy samples, etc.)
Author Response
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Reviewer 2 Report
Reviewer Comments
The followings should be carefully addressed in the revision to be published in Journal of Applied Sciences.
1- The abstract still needs more quantitative results. Please provide your contribution and work novelty.
2- Add references for all equations.
3- I would also expect to validate with two more experimental works available in the literature.
4- You need to add error analysis of your results and add the error bars in your graphs to indicate your accuracy measurements.
5- Improve work justification.
6- More quantitative conclusions should be presented.
7- Authors should discuss limitations of the current study and possible improvements for future directions/research works.
Author Response
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