On the Use of Molecular Dynamics Simulations for Elucidating Fine Structural, Physico-Chemical and Thermomechanical Properties of Lignocellulosic Systems: Historical and Future Perspectives
Round 1
Reviewer 1 Report
In the manuscript, Prasad et al. reviewed the history of using MD simulation to study mechanical and physical properties of the lignocellulosic system, a brief and proper introduction of MD methodology was included as well. The review is comprehensive and covers important progress of MD study development. This would be interesting and beneficial to the MD and wood material communities. I only have a couple of minor comments below:
- Pg.8 line 257 there is a reference error that needs to be fixed
- Sec. 2 is quite lengthy, it could help if authors make it into subsections based on time or type of studies, though it's not mandatory
- If possible, would the authors be able to predict the approximate max size of the MD system (# of atoms, time period, size, etc.) the current computer center in the world could simulate? This may provide some insight on how far away we are from bridging MD simulation to continuous material theory
Author Response
In the manuscript, Prasad et al. reviewed the history of using MD simulation to study mechanical and physical properties of the lignocellulosic system, a brief and proper introduction of MD methodology was included as well. The review is comprehensive and covers important progress of MD study development. This would be interesting and beneficial to the MD and wood material communities. I only have a couple of minor comments below:
1. Pg.8 line 257 there is a reference error that needs to be fixed
This has been fixed.
Sec. 2 is quite lengthy, it could help if authors make it into subsections based on time or type of studies, though it's not mandatory
We understand the reviewer’s point of view but feel that the current length of the section provides a proper context regarding the historical and modern developments in MD simulation of lignocellulosic systems.
If possible, would the authors be able to predict the approximate max size of the MD system (# of atoms, time period, size, etc.) the current computer center in the world could simulate? This may provide some insight on how far away we are from bridging MD simulation to continuous material theory
Systems of sizes up to several million atoms can be currently simulated using classical MD but by using coarse grained approaches where groups of atoms form the basis of the simulation it is possible to achieve simulation of trillions of atoms. An example of this approach can be seen in Tchipev et al, The International Journal of High Performance Computing Applications2019, Vol. 33(5) 838–854. In terms of time scales, nanoseconds are the most common and can take from 1 to several days to achieve. Microsecond simulation are also becoming more achievable but can still take several weeks’ worth of computational time. The current state of the art computing systems that can successfully carry out such massive simulations include the SuperMUC Phase 1, TianHe-2, etc.
Reviewer 2 Report
The review by K. Prasad, M. Nikzad, S.S. Nisha, and I. Sbarski is devoted to molecular dynamics (MD) simulations of lignocellulosic systems and study of the mechanical, thermal and other properties of these systems.
In the manuscript the authors provide a historical review of research on the computer simulation of lignin-containing systems and describe the current state of rthe art in this field.
It should be noted that the computer simulation is the modern comprehensive tool to study molecular properties of of polymer systems. Taking into account complex chemical structure of lignocellulosic systems MD studies of such substances could be nontrivial task. Thus, the review summarazing current prospective on this topic could be of great interest for both theoretical researchers who perform MD study of similar systems and experimentalists.
From my point ov view the review presented is well written and describe all aspects of the subject review. It can be published in present form.
Author Response
The review by K. Prasad, M. Nikzad, S.S. Nisha, and I. Sbarski is devoted to molecular dynamics (MD) simulations of lignocellulosic systems and study of the mechanical, thermal and other properties of these systems.
In the manuscript the authors provide a historical review of research on the computer simulation of lignin-containing systems and describe the current state of the art in this field.
It should be noted that the computer simulation is the modern comprehensive tool to study molecular properties of polymer systems. Taking into account complex chemical structure of lignocellulosic systems MD studies of such substances could be nontrivial task. Thus, the review summarizing current prospective on this topic could be of great interest for both theoretical researchers who perform MD study of similar systems and experimentalists.
From my point of view the review presented is well written and describe all aspects of the subject review. It can be published in present form.
We thank the reviewer for their supportive remarks.
Reviewer 3 Report
The review presented by the authors is very interesting and well organised and only few modifications should be done:
- Lines 257–258: seems to be an error regarding the reference;
- Line 299: correct the term “gyrmnospermous” in “gymnospermous”
- The authors should add a section in the Introduction regarding the chemical structure of polymers in the lignocellulosic biomass (lignin, cellulose and hemicellulose) in order to make easier the understanding of the following Paragraphs for the reader.
- Lines 346–350: which were the conclusions/observations of the work of Ganster and Blackwell?
- Line 554: specify what means “IL”. Does it stay for “ionic liquids”?
Author Response
The review presented by the authors is very interesting and well organised and only few modifications should be done:
Lines 257–258: seems to be an error regarding the reference;
This error has been rectified and the section number (2) has been included in Line 257 of the revised manuscript.
Line 299: correct the term “gyrmnospermous” in “gymnospermous”
This correction has been made in line 337 in the revised manuscript.
The authors should add a section in the Introduction regarding the chemical structure of polymers in the lignocellulosic biomass (lignin, cellulose and hemicellulose) in order to make easier the understanding of the following Paragraphs for the reader.
An introductory section regarding the composition and uses of lignocellulosics has been included in the revised manuscript (Section 1.3)
Lines 346–350: which were the conclusions/observations of the work of Ganster and Blackwell?
The conclusions of Ganster and Blackwell have been summarised and also noted in Figure 2-5 and Table 2-1 in lines 392-397 of the revised manuscript.
Line 554: specify what means “IL”. Does it stay for “ionic liquids”?
It does stand for ionic liquid and has been mentioned in line 585 of the revised manuscript.
Reviewer 4 Report
In this contribution, authors report on the use of Molecular Dynamics (MD) simulations for predicting subtle structural, thermomechanical and related characteristics of lignocellulosic systems.
The topic is of high relevance, being timely and a hot topic at the moment.
The paper is solid, however, the main problem is that in the introduction a general description of lignocellulosic biomasses and in their use in modern society and biorefineries. This part is strictly necessary and paper cannot be accepted without this part.
Author Response
In this contribution, authors report on the use of Molecular Dynamics (MD) simulations for predicting subtle structural, thermomechanical and related characteristics of lignocellulosic systems.
The topic is of high relevance, being timely and a hot topic at the moment.
The paper is solid, however, the main problem is that in the introduction a general description of lignocellulosic biomasses and in their use in modern society and biorefineries. This part is strictly necessary and paper cannot be accepted without this part.
A description of the various uses of lignocellulosic biomasses and materials derived from lignocellulosic biomasses in modern society has been included (Section 1.3).
Round 2
Reviewer 4 Report
Authors successfully address raised points. Paper can be accepted in the present form
