Minimizing Transportation Damage of Murals: Application of Wire Rope Isolators and Real-Time Vibration Monitoring in the Case Study of Diego Rivera’s ‘Pan American Unity’

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Summary and General Assessment

The article addresses a very interesting and practically significant topic — the minimization of vibrations during the transportation of monumental artworks, illustrated by the case of Diego Rivera’s mural “Pan American Unity.” The authors present a comprehensive engineering solution combining a passive vibration isolation system (wire rope isolators) with an active real-time monitoring system. I consider this a solid piece of engineering work with high practical value, particularly relevant for conservators and engineers involved in cultural heritage protection, as well as for transport specialists handling fragile or high-mass materials.

 

From my perspective, the manuscript is carefully and clearly prepared, with its main strength lying in the close integration of science and practice. Although the paper is not groundbreaking in terms of scientific novelty, it represents a valuable case study that effectively documents the performance of a specific technical solution.

 

Major Comments

 

1. Background and Literature Review – The introduction is adequate, but it could be strengthened by including more recent publications related to the transportation of artworks, atypical cargo, or active vibration control systems. This would help situate the paper more firmly within the context of current research.

 

2. Novelty and Scientific Contribution – The authors should more explicitly highlight what is innovative in their approach. For instance, to what extent is the integration of real-time monitoring with passive isolators novel compared to previous studies or scientific publications? At present, the paper occasionally reads more like an engineering project report than a traditional research article.

 

3. Study Limitations – It would be useful to add a brief discussion of the limitations of the proposed method, e.g., that the analysis was conducted for a single transport case under specific conditions in San Francisco. This would allow readers to better assess the generalizability of the results.

 

4. Figures and Structure – The figures and tables are generally well prepared; however, some captions are too concise and do not fully convey the context of the presented data.

 

              - For example, Figure 6 (sensor layout) could include a short clarification that the SR1–SR5 configuration allowed for vibration measurement along        different axes and was essential for dynamic analysis.

 

              - Table 1, presenting vibration thresholds and color codes, should mention that the values were derived from earlier destructive tests on a mock-up of     the mural.

 

              - In the case of Figures 10 and 11, the captions could emphasize the main finding — the reduction in vibration amplitude between the truck input and        the mural panel response.

              Adding such contextual details would make the graphical section more self-explanatory and easier to interpret without constant reference to the         main text.

 

5. Author Contributions – The Author Contributions section should be aligned with MDPI standards (e.g., “conceptualization,” “data curation,” “software,” “visualization,” etc.), which would improve the transparency of each author’s role.

 

6. Data Analysis and Statistical Aspects – The vibration results are clearly presented; however, the paper lacks discussion of measurement uncertainty or basic statistical analysis (e.g., standard deviations, measurement errors). Although this is not critical for an application-oriented paper, including even simple indicators of repeatability or error range would, in my view, enhance the credibility of the reported results.

 

7. Sensor Calibration and Data Quality Control – In Section 2.2, it would be worth briefly describing how the accelerometers were calibrated and how the quality of the recorded data was verified. Indicating whether validation procedures (e.g., repeated reference measurements) were applied would increase the transparency of the methodology.

 

8. Implementation Aspects – In my opinion, the practical value of the paper could be further improved if the authors added a brief discussion on the economic or operational constraints of the proposed system (e.g., scalability for smaller museum objects).

 

9. Future Research Directions – In future work, the authors could consider extending the system with predictive functionalities or analyses based on machine learning methods, enabling the forecasting of potential vibration exceedances along transport routes.

 

Language Comments

The English language in the manuscript is generally good; however, some sentences are overly complex and could be simplified. I recommend minor language editing to improve readability and flow.

Since English is not my native language, I do not take a definitive position regarding grammar or stylistic aspects.

 

Final Impression

The paper made a positive impression on me due to its attention to detail and interdisciplinary character. From my experience, such works — even without significant theoretical innovation — are highly valuable for engineering practice and cultural heritage preservation. After addressing the minor textual and methodological improvements mentioned above, the paper deserves publication in Applied Sciences.

Comments on the Quality of English Language

The overall quality of the English language is good, and the manuscript is understandable. However, some sentences are overly long and could be simplified to improve readability. Minor grammatical corrections, style adjustments, and consistency in terminology would further enhance the clarity and flow of the text. I recommend a light language editing to make the manuscript more concise and polished. Since English is not my native language, I do not take a definitive position on this aspect.

Author Response

We would like to extend our sincere thanks to the reviewer for their thorough and constructive feedback. Your insightful comments and suggestions have been invaluable in improving the overall quality of our manuscript. We have carefully addressed each point raised, and we believe the revisions have significantly enhanced the clarity, depth, and context of our research. The paper is much stronger as a result of your input.

 

Comments 1: [Background and Literature Review – The introduction is adequate, but it could be strengthened by including more recent publications related to the transportation of artworks, atypical cargo, or active vibration control systems. This would help situate the paper more firmly within the context of current research.]

Response 1: [Dear reviewer, we agree that positioning our work within the most current research landscape is crucial. Accordingly, we have expanded the literature review in the Introduction to include a discussion on recent advancements in the field, such as the response of museum objects during transportation and active vibration control systems, citing relevant contemporary publications. We believe this new context more clearly situates our study and highlights the practical value of our approach. Corrections in the introduction]

 

Comments 2: [Novelty and Scientific Contribution – The authors should more explicitly highlight what is innovative in their approach. For instance, to what extent is the integration of real-time monitoring with passive isolators novel compared to previous studies or scientific publications? At present, the paper occasionally reads more like an engineering project report than a traditional research article.]

Response 2: [We appreciate the reviewer's critical feedback on this point. To more explicitly highlight the novelty of our work and frame it as a research article, we have extended the last paragraph or introduction. This new redaction articulates that the primary innovation is the synergistic integration and rigorous quantitative validation of the passive isolation system with the real-time, human-in-the-loop monitoring protocol. We believe this clarification effectively elevates the manuscript from an engineering report to a scientific contribution with a replicable framework. Corrections in lines 76-84]

 

Comments 3: [Study Limitations – It would be useful to add a brief discussion of the limitations of the proposed method, e.g., that the analysis was conducted for a single transport case under specific conditions in San Francisco. This would allow readers to better assess the generalizability of the results.]

Response 3: [We have added a couple of paragraphs at the discussion, in this part, we explicitly discuss the limitations of our study, including its nature as a single case study, the reliance on a passive system, and the human-in-the-loop aspect of the monitoring. We believe this provides a more balanced perspective and helps the reader better assess the applicability of our findings to other contexts. Corrections in lines 381-398]

 

Comments 4: [Figures and Structure – The figures and tables are generally well prepared; however, some captions are too concise and do not fully convey the context of the presented data]

Response 4: [We are grateful for this detailed and constructive feedback. We have revised the captions for Figure 6, Table 1, Figures 10, and Figure 11 to be more descriptive and self-explanatory. Each caption now incorporates the specific contextual details suggested by the reviewer, which we agree makes the graphical section significantly easier to interpret without constant reference to the main text. Corrections in fig 6, 10, 11,12 and table 1]

 

Comments 5: [Author Contributions – The Author Contributions section should be aligned with MDPI standards (e.g., “conceptualization,” “data curation,” “software,” “visualization,” etc.), which would improve the transparency of each author’s role.]

Response 5: [We have updated the "Author Contributions" section to align with the CRediT (Contributor Roles Taxonomy) standard used by MDPI, providing a more transparent and standardized description of each author's role in the research. Corrections in lines 437-444]

 

Comments 6: [Data Analysis and Statistical Aspects – The vibration results are clearly presented; however, the paper lacks discussion of measurement uncertainty or basic statistical analysis (e.g., standard deviations, measurement errors). Although this is not critical for an application-oriented paper, including even simple indicators of repeatability or error range would, in my view, enhance the credibility of the reported results.]

Response 6: [To address this, we have added a brief discussion at the end of Section 2.2 ("Instrumentation"). We now specify the factory calibration uncertainty of the sensors (±5%) and mention the verification procedures performed. While a full statistical error propagation was outside the scope of this applied study, we believe this addition enhances the credibility and transparency of our reported results. Corrections in lines 177-179]

 

Comments 7: [Sensor Calibration and Data Quality Control – In Section 2.2, it would be worth briefly describing how the accelerometers were calibrated and how the quality of the recorded data was verified. Indicating whether validation procedures (e.g., repeated reference measurements) were applied would increase the transparency of the methodology.]

Response 7: [We have expanded Section 2.2 ("Instrumentation") to include details on the factory calibration of the accelerometers and the simple quality control checks (tap tests) that were performed pre-transit to ensure data integrity. We believe this information strengthens the methodological description. Corrections in lines 177-180]

 

Comments 8: [Implementation Aspects – In my opinion, the practical value of the paper could be further improved if the authors added a brief discussion on the economic or operational constraints of the proposed system (e.g., scalability for smaller museum objects).]

Response 8: [This is an excellent suggestion to improve the practical value of the paper. We have added a new paragraph to the "Discussion" section that addresses the economic and operational constraints of the proposed system. We discuss the cost of the isolators relative to the value of the artwork and consider the operational requirements and scalability for smaller objects, providing a more complete picture for practitioners in the field. Corrections in lines 389-397]

 

Comments 9: [Future Research Directions – In future work, the authors could consider extending the system with predictive functionalities or analyses based on machine learning methods, enabling the forecasting of potential vibration exceedances along transport routes.]

Response 9: [We have revised the "Future Research Directions" section within our conclusion to be more specific and impactful. We now explicitly propose the development of predictive functionalities based on machine learning to develop a predictive alert system. Corrections in lines 427-430]

Reviewer 2 Report

Comments and Suggestions for Authors

Dear authors, there are many points I would like to address.

Generally, the paper loos too much descriptive, without any deep description of the activity or justification of the choices. imagining that another research could replicate your attainments by reading the paper is hardly possible.

The introduction is really short and the reference cited seem too few to cover all what has been done in the field, all over the world. I would suggest a more extensive investigation, trying to get more info from past activities.

The objective is well stated and also the innovation: line 53-56, gap analysis, and lines 64-66 and 67-69, novelty. I would move from this statements to perform a devoted bibliographic research. Keywords are fundamental, in my opinion.

There is a declared process of identification f the structure that is not described (lines 105-111). Details are not provided for a very interesting activity. Now, if the process is not interesting for the publication, authors should not have cited it. If it is, why you omit details? Either, did you publish this accomplishment somewhere else? if it is so, I would have expected to find a reference about that. Please, would you clarify.

Figure 4 could be clearer. May be a zoom with label could be fine, as the layout seems the same for upper and lower panels.

Why coarse, medium and fine marble powder have the same size? (4-150 microns). Is there a typo?

Concerning the displacement of accelerometers, I was wondering how it was established. I fear I dd not find anything in the text, explaining the deployment logic. Why 5?

A comment aside. Accelerometers measure accelerations, therefore even "rigid mode motion". If synchronous, this "movements should not be that important for the system safety (maybe). On the other side, the vibrations developing as waves over the article, could lead to dramatic phenomena. Did the authors think to use piezoelectric patches, instead or together with the accelerometers?, they would give info exclusively n deformation, therefore, being closer to the real interest of preserving the system to be taken care of.

A resolution of 200 Hz, means that the max frequency observable is 100 Hz and a reasonable estimate of the amplitude may occur under 50 Hz (roughly). Is that sufficient for the investigation?

In table 1 there are values of acceleration, reported. Is the max value of 4 G associated to a regulation or a standard? Was it established experimentally? How the other levels were chosen? Please, would you explain.

Line 187-189. Clear the weight of the panel. clear the load capacity of the spring. Shall I assume two springs are used for each panel? At the bot bottom sides of the panel? in that case "the substantial safety factor" can be computed and shown. Please would you integrate. 

Line 199-201 "By selecting an isolator with a natural frequency of 3.4 Hz, the system was designed to operate well within the isolation region of the transmissibility curve..." Now... it should be considered that the system made to be "isolated" is the system made of the panel and the springs. therefore it has little sense to speak about the frequency of the isolator eigenfrequency. Since the springs are two per panel (is it right? I didn't find this information). i expect the mass spring system have at least two modes in the low frequency range. The lower is the resonant frequencies, the better. Did the author evaluate these frequencies (two for two springs, many more for three and four springs). These values are crucial to better understand the diagrams that were reported following. A modal analysis would be interesting.

How was the isolator chosen? Any alternative available?

Fig.10 Time response bring few information. In any case, I would suggest the diagrams report all the same axis. ranges.

Fig.11 put the diagrams in different scales, so that it's hard to make a direct comparison. The axis range should not go further 50 Hz for what said above... as almost done with Figure 12.

As it is understood the authors did not perform any modal analysis, numerical or experimental, of the panels (isolated) and the panels (installed). Is t correct?

In the discussion "The observed resonant frequency of approximately 8 Hz is consistent with the specifications of the designed isolators for the given panel mass, confirming a correct system design." It is the first time I read about specifications in the document. Where does 8 Hz come from?

The Conclusions paragraph seems more a summary than else. I expected to find a deep critical review of what were the stated aims, the difficulties on the field, ad the problems hat were solved for a correct implementation. And, finally, a future perspective for further achievement.

Concluding... a descriptive text with some hot points missing and some decisions to be better justified. I expect to have a fully revised version of the paper to formulate my final evaluation.

 

 

 

 

 

Author Response

We sincerely appreciate the reviewer's critical and thought-provoking evaluation of our manuscript. Your challenging questions prompted us to revisit and more deeply justify our core methodological choices, which has fundamentally strengthened the scientific foundation of the paper. We have undertaken a comprehensive revision to address all of your concerns, and we are confident that the manuscript is now a much more robust and well-supported contribution thanks to your feedback.

 

Comments 1 [Generally, the paper loos too much descriptive, without any deep description of the activity or justification of the choices. imagining that another research could replicate your attainments by reading the paper is hardly possible.]

Response 1 [We acknowledge that previous versions of the manuscript were overly descriptive. In this comprehensive revision, we have taken this comment to heart and have made a concerted effort to deepen the technical descriptions, justify our methodological choices, and provide the necessary details to enhance replicability. The specific changes, detailed in our responses below, address this point by adding new subsections on preliminary testing, justifying sensor placement, clarifying system design parameters, and expanding the analytical discussions throughout the paper.]

 

Comments 2 [The introduction is really short and the reference cited seem too few to cover all what has been done in the field, all over the world. I would suggest a more extensive investigation, trying to get more info from past activities. The objective is well stated and also the innovation: line 53-56, gap analysis, and lines 64-66 and 67-69, novelty. I would move from this statements to perform a devoted bibliographic research. Keywords are fundamental, in my opinion.]

Response 2 [We agree completely with the reviewer that the original introduction and literature survey were insufficient. We have significantly expanded the Introduction to provide a more comprehensive review of the state-of-the-art, citing additional literature on passive, semi-active, and active control systems, as well as IoT applications. We believe this new section provides a much stronger context and a clearer gap analysis for our work. Corrections on lines 44-65]

 

Comments 3 [There is a declared process of identification f the structure that is not described (lines 105-111). Details are not provided for a very interesting activity. Now, if the process is not interesting for the publication, authors should not have cited it. If it is, why you omit details? Either, did you publish this accomplishment somewhere else? if it is so, I would have expected to find a reference about that. Please, would you clarify.]

Response 3 [Dear reviewer, thank you for that comment. The identification process, although laborious and complicated, is not relevant to the article. Only the composition of the steel structure is relevant to understand the mass magnitude and dimensions of the panels. The redaction in that section has been improved. Corrections on lines 115-121]

 

Comments 4 [Figure 4 could be clearer. May be a zoom with label could be fine, as the layout seems the same for upper and lower panels.]

Response 4 [Figure 4 has been revised, A detail of the structure is shown in enlargement with its labels to identify the key components of the structure, improving its clarity. Corrections on line 123]

 

Comments 5 [Why coarse, medium and fine marble powder have the same size? (4-150 microns). Is there a typo?]

Response 5 [We are grateful to the reviewer for catching this error. This was indeed a typographical error in the manuscript. The text has now been corrected to reflect the distinct particle size ranges used for the coarse, medium, and fine marble powders. Corrections on lines 126-140]

 

Comments 6 [Concerning the displacement of accelerometers, I was wondering how it was established. I fear I dd not find anything in the text, explaining the deployment logic. Why 5?]

Response 6 [A new paragraph has been added to the Instrumentation section (now 2.2) to explain the logic behind the accelerometer deployment. We clarify that the five-sensor layout was chosen strategically to capture the point of maximum flexibility of the mural (center sensor) as well as upper and lower accelerations (corner sensors). Corrections on lines 153-156]

 

Comments 7 [A comment aside. Accelerometers measure accelerations, therefore even "rigid mode motion". If synchronous, this "movements should not be that important for the system safety (maybe). On the other side, the vibrations developing as waves over the article, could lead to dramatic phenomena. Did the authors think to use piezoelectric patches, instead or together with the accelerometers?, they would give info exclusively n deformation, therefore, being closer to the real interest of preserving the system to be taken care of]

Response 7 [This is an insightful comment. While accelerometers were sufficient for the objectives of this study, we agree that strain-based sensors offer a different and valuable type of information. We have added a comment in the Discussion section acknowledging the potential of piezoelectric patches for future work focused specifically on material deformation and stress analysis. Corrections on line 431-433]

 

Comments 8 [A resolution of 200 Hz, means that the max frequency observable is 100 Hz and a reasonable estimate of the amplitude may occur under 50 Hz (roughly). Is that sufficient for the investigation?]

Response 8 [We have added a statement to the Instrumentation section (2.3) justifying the choice of a 200 Hz sampling frequency. We explain that this rate provides a reliable analysis bandwidth up to 50 Hz, which our results confirm is sufficient to capture the entire spectrum of significant energy from road-induced vibrations. Whose main vibrations occur at a frequency between 10 and 30 Hz. Corrections on lines 160-163]

 

Comments 9 [In table 1 there are values of acceleration, reported. Is the max value of 4 G associated to a regulation or a standard? Was it established experimentally? How the other levels were chosen? Please, would you explain.]

Response 9 [We expand on section 2.3 regarding the Light Indicator. The 4G threshold is not based on a general rule, but was established experimentally as the level corresponding to the observed onset of microcracks in our full-scale mock up. We explain that this destructive experimental procedure was performed due to the unique composition of Diego Rivera's mural, for which there is no material mechanics data. Corrections on lines 212-222]

 

Comments 10 [Line 187-189. Clear the weight of the panel. clear the load capacity of the spring. Shall I assume two springs are used for each panel? At the bot bottom sides of the panel? in that case "the substantial safety factor" can be computed and shown. Please would you integrate.]

Response 10 [Dear reviewer, thank you for pointing out the lack of detail in the number of wire rope isolators used. We have already specified this information in the second paragraph of section 2.4 and in Figure 8. The weight and safety factor for each panel were also specified. Corrections on lines 252-259]

 

Comments 11 [Line 199-201 "By selecting an isolator with a natural frequency of 3.4 Hz, the system was designed to operate well within the isolation region of the transmissibility curve..." Now... it should be considered that the system made to be "isolated" is the system made of the panel and the springs. therefore it has little sense to speak about the frequency of the isolator eigenfrequency. Since the springs are two per panel (is it right? I didn't find this information). i expect the mass spring system have at least two modes in the low frequency range. The lower is the resonant frequencies, the better. Did the author evaluate these frequencies (two for two springs, many more for three and four springs). These values are crucial to better understand the diagrams that were reported following. A modal analysis would be interesting.]

Response 11 [This is an excellent and precise point. We have revised Section 2.4 to correct our language and focus on the natural frequency of the entire isolated system, not just the isolator component. We now discuss the design goal of targeting a low system frequency and explicitly link this design choice to the experimentally measured resonant frequency of ~8 Hz observed later in the transmissibility plot, making the entire argument more coherent. There are eight wire rope insulators supporting the panels vertically, and two more supporting them horizontally. A mode analysis was not performed; we'll explain the reason for this in answer 14. Corrections on line 260-269]

 

Comments 12 [How was the isolator chosen? Any alternative available?]

Response 12 [To better justify our design choices, we have extended the paragraph one in Section 2.4 detailing the selection criteria for the wire rope isolators. We also briefly discuss alternatives (elastomeric mounts, air-springs) and explain why they were considered less suitable for this specific high-stakes application. Corrections on lines 241-246]

 

Comments 13 [Fig.10 Time response bring few information. In any case, I would suggest the diagrams report all the same axis. ranges. Fig.11 put the diagrams in different scales, so that it's hard to make a direct comparison. The axis range should not go further 50 Hz for what said above... as almost done with Figure 12.]

Response 13 [We agree with the reviewer that the original plots were not optimal for comparison. We have regenerated Figures 10 and 11. In the new Figure 10, the y-axes for the truck and panel responses for each direction are now linked to share the same scale, allowing for direct visual comparison of amplitude reduction. In Figure 11 and 12, the frequency axis has been limited to 50 Hz, which, as the reviewer noted, focuses on the relevant analysis bandwidth. Corrections on line 294]

 

Comments 14 [As it is understood the authors did not perform any modal analysis, numerical or experimental, of the panels (isolated) and the panels (installed). Is t correct?]

Response 14 [That is correct; a comprehensive experimental or numerical modal analysis was not conducted as part of this study's scope. A numerical analysis was deemed unfeasible due to the unique and poorly documented material properties of Diego Rivera's fresco mixtures, which include natural fibers and idiosyncratic formulations. A simulation based on the mechanical properties of traditional cementitious materials would likely yield results that deviate significantly from reality. Conversely, performing an experimental modal analysis on the original mural panels was not permissible due to conservation constraints. Therefore, we have proposed that a future, more detailed investigation should involve the fabrication of a new full-scale mock-up specifically for the purpose of conducting a thorough experimental modal analysis. This recommendation is now included in the "Limitations and Generalizability" and "Future Work" sections. Corrections on lines 424-247]

 

Comments 15 [In the discussion "The observed resonant frequency of approximately 8 Hz is consistent with the specifications of the designed isolators for the given panel mass, confirming a correct system design." It is the first time I read about specifications in the document. Where does 8 Hz come from?]

Response 15 [Dear reviewer, thank you for pointing out that detail in the narrative. We have modified the discussion section to note that the 8 Hz is related to the resonance of the panel and dampers assembly, not the independent damper, whose equivalent resonance frequency is 3.4 Hz as specified in section 2.4. Corrections on lines 362-367]

 

Comments 16 [The Conclusions paragraph seems more a summary than else. I expected to find a deep critical review of what were the stated aims, the difficulties on the field, ad the problems hat were solved for a correct implementation. And, finally, a future perspective for further achievement.]

Response 16 [We concur with the reviewer's assessment that the original conclusion was too simplistic. The "Conclusions" section has been completely rewritten to provide a more critical reflection on the study. It now frames the results in the context of the initial challenges (e.g., the unique material composition), discusses the solved problems (the successful synergy of the passive and active systems), and provides a more focused and impactful perspective on future achievements, as recommended. Corrections on conslusions.]

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript presents a case study of the transport of a mural, focusing on the design, implementation, and evaluation of a wire rope isolator (WRI) system coupled with real-time vibration monitoring. The paper is well-written. However, several aspects could be improved to enhance clarity, reproducibility, and depth. The originality is moderate, as WRI have been previously applied to shock-safe transport, but the integration with real-time feedback systems in a large-scale mural context is novel and significant.

1) The vibration signal processing methodology (Welch’s method) is briefly mentioned but lacks sufficient parameters (e.g., window size, overlap, averaging details).

2) The calibration and uncertainty of sensors (MinIMU-9 v5) are not discussed. Since these are low-cost IMUs, their accuracy and drift behavior should be justified.

3) The authors should clarify how destructive tests (Table 1) were performed and whether these were statistically representative or single-event thresholds.

4) Some figures (e.g., Figures 2–4) would benefit from higher contrast and labeled elements.

5) References are current and relevant but limited in number (10). The paper would benefit from including recent literature on:
- Smart sensing and IoT for heritage monitoring (e.g., 2020–2024 studies).
- Semi-active or magnetorheological isolator systems for vibration control.
- Recent standards or guidelines (e.g., EN 15946 or AIC transport recommendations).

Author Response

We are very grateful to the reviewer for their detailed and insightful technical review. Your keen eye for methodological detail has allowed us to substantially improve the transparency and scientific rigor of our paper. The manuscript has been revised to incorporate your suggestions, particularly concerning the signal processing parameters and sensor justifications, which we agree enhances its reproducibility. Thank you for your valuable contribution.

 

Comments 1: [The vibration signal processing methodology (Welch’s method) is briefly mentioned but lacks sufficient parameters (e.g., window size, overlap, averaging details).]

Response 1: [Dear reviewer, thanks for pointing out this lack of detail. For clarity and reproducibility, we have expanded the methodology section to include the specific parameters used for the Welch's method analysis. We now specify that a 2-second Hann window was used with a 50% overlap between segments. Corrections on lines 186-191]

 

Comments 2: [The calibration and uncertainty of sensors (MinIMU-9 v5) are not discussed. Since these are low-cost IMUs, their accuracy and drift behavior should be justified.]

Response 2: [We have expanded Section 2.2 to justify the use of the MinIMU-9 v5 sensors. We now explicitly discuss that IMUs, their suitability stems from the relative nature of our primary metric (transmissibility), which minimizes the impact of absolute calibration errors. We also address that long-term drift is not a significant concern for the short duration of the transport events. Details on factory calibration and our pre-test verification procedure have also been included to enhance methodological transparency. Corrections on lines 178-081]

 

Comments 3: [The authors should clarify how destructive tests (Table 1) were performed and whether these were statistically representative or single-event thresholds.]

Response 3: [We have amended Section 2.3 to provide more detail on the derivation of the alert thresholds. We now explicitly state that the values in Table 1 were determined empirically from controlled vibration and impact tests on the full-size mock-up panel and represent conservative, single-event thresholds corresponding to the observed onset of micro-cracking, rather than being derived from a full statistical analysis. This was a necessity dictated by the unique and complex composition of the mural itself. Corrections on lines 212-222]

 

Comments 4: [Some figures (e.g., Figures 2–4) would benefit from higher contrast and labeled elements]

Response 4: [We have revised Figures 2, 3, and 4 to improve their visual clarity. We have added labels to identify key components, as recommended. We agree that these changes make the figures more informative and easier to interpret. Corrections on fig 2-4]

 

Comments 5: [References are current and relevant but limited in number (10). The paper would benefit from including recent literature on:
- Smart sensing and IoT for heritage monitoring (e.g., 2020–2024 studies).
- Semi-active or magnetorheological isolator systems for vibration control.
- Recent standards or guidelines (e.g., EN 15946 or AIC transport recommendations).]

Response 5: [We are grateful for these excellent literature suggestions, which have significantly strengthened the context of our paper. We have expanded our literature review to include recent publications on active vibratión sensing and advanced semi-active isolator systems. We believe these additions better situate our work within the current state-of-the-art. Corrections on introduction]

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Thanks to the authors to have gone thoroughly along the comments that were provided and have inserted so duly the requested upgrades. The paper has then been widely updated, 

As it is reports the results of an actual activity carries out along a discrete amount of time, it will surely meet the interest f some reader and may be seen as a reference for similar activities.

Therefore I propose it can be published.