In Situ Detection of the Flexural Fracture Behaviors of Inner and Outer Bamboo-Based Composites
Round 1
Reviewer 1 Report (Previous Reviewer 1)
Dear Editor of Forests
Thank you very much for inviting me to review the revised manuscript “In situ detection of the flexural fracture behaviors of Scrimber with inner and outer bamboo.” The authors have made significant English editing, and the manuscript is better now. However, the manuscript still contains serious flaws, and My comments are below.
Best Regards
Reviewer
1. Line 1: “Title”. The term “Scrimber” disagrees with their specimens. Their specimens were made from bamboo strips. Bamboo scrimber is a fiber-based composite made from crushed bamboo fiber (zephyr). [https://doi.org/10.1186/s10086-019-1806-4 and https://doi.org/10.3390/f14010146]. Please find the correct terms for your specimens.
2. Line 28: “Bamboo is … ,…., and the highest-yielding natural material on Earth” The statement “Bamboo is the highest-yielding natural material on Earth” is an exaggerated claim without solid justification. Many other organisms yield more natural material than bamboo on earth (such as grass, corn, rice, bean, kernel, wheat, other agricultural plants, livestock, animal farms, and fisheries). The cited reference (Lugt et al., 2006 https://doi.org/10.1016/j.conbuildmat.2005.02.023) did not have contents of that statement. Please be more careful when making a claim.
3. Line 31: “However, the bamboo is …….and the quality do not meet the requirements of wood construction, which do not used as engineered building materials.” The statement “Bamboo quality do not meet the requirements of wood construction, which do not used as engineered building materials” is a serious accusation that opposes the indisputable fact. Bamboo has been used as a construction material since ancient times until today. Many fascinating green buildings are built using round bamboo as their primary structural member. The recent development also justifies the reliability of the structural grade of bamboo, and the international building code for bamboo construction, such as ISO 22156:2021, is also available.
Please consider these statements:
Bamboo is also used in the paper, food and evidently in the building industry. Especially for the less wealthy population in tropical areas, bamboo plays a very important role in daily lives (shelter, employment, income, fuel, etc.). Recently, bamboo has also found more applications in the West, in industrial applications as well as in temporary structures. The favourable environmental performance of the bamboo culm has two distinct causes. First, its natural hollow design is structurally far more efficient than a rectangular massive section, e.g., in case of timber. This means that, in comparison with steel, concrete and timber, for a certain load-bearing capacity, bamboo contains less material mass. The second cause is the simple, short production process of bamboo (sawing, removal of branches, preservation, drying). Since problems related to the shape and irregularity of bamboo are inherent to its natural character, they can only be diminished, not completely avoided. Laminating bamboo for rectangular products will diminish problems caused by the shape, however, the study presented demonstrated a relatively great increase of environmental load in that case. [https://doi.org/10.1016/j.conbuildmat.2005.02.023].
Bamboo is a feasible alternative in design and civil construction to alleviate the excessive use of steel, concrete, oil byproducts, and timber and to reduce the logging of the forest. The talented architects design sustainable bamboo buildings in an aesthetically pleasing and cost-competitive for humanitarian projects around the world [i.e., the green school in Bali (Indonesia), Bamboo Pavilion in Chongming (China), dubbed Cubo housing units in Manila (Philipines), and sustainable ecological village in the Amazon (Brazil)]. Round bamboo has been traditionally applied for building structural components (i.e., flooring, walls, roofing, concrete reinforcement, and scaffolding) with substantial environmental benefits. Traditional bamboo construction technology has become a part of the community’s socio-culture; therefore, reviving, advancing, and disseminating such traditional technology to the people can strengthen the self-reliance of local communities. [https://doi.org/10.1016/j.rineng.2023.100911].
ISO 22156:2021 applies to the design of bamboo structures whose primary load-bearing structure is made of round bamboo or shear panel systems in which the framing members are made from round bamboo. It permits the construction design of a bamboo structure following ASD (allowable stress design), ACD (allowable load-bearing capacity design), or combined. ISO 22156:2021 also recognizes the PSFD (partial safety factor design) or LRFD (load and resistance factor design). [https://doi.org/10.1007/978-981-19-9327-5_9].
4. Line 73 – 75: Please state how much is the pressure (in the MPa unit) when conducting the hot press. Since the four plies of 1 mm layers are composed to make a 2 mm thickness of a specimen, there shall be a densification mechanism. Please consider discussing these densification results, including density, moisture content, and specific gravity of both bamboo and the products.
5. Line 82 – 83: “30 (l)×2 (t)×2 (r) mm3.” Line 91: “5 (l)×2 (t)×2 (r) mm3” It is unfair to compare the densified products and the raw material’s mechanical properties using the same dimension of specimens because they are made from different amounts of raw material. A 5 (l)×2 (t)×2 (r) mm3 of the densified products was made from 5 (l)×2 (t)×4 (r) mm3 of the raw bamboo. Please consider comparing the 5 (l)×2 (t)×4 (r) mm3 raw bamboo specimen with the 5 (l)×2 (t)×2 (r) mm3 densified products.
6. Line 112 – 195: “The bending force in scrimber was ~50 N, which was higher than that of bamboo. Figure 2, and Figure 5.” This data was obtained from an unfair comparison. Please consider comparing the same amount of raw material. The raw bamboo material’s thickness shall be 4 mm to make a fair comparison with the 2 mm thickness of densified products because hot press densified 4 mm bamboo to become 2 mm products.
7. Line 234 – 235: Figure 8. The graph of modulus coincide with hardness; thus, they are hard to read. Please consider adding a small horizontal space between modulus and hardness line.
8. Subchapter 4. The discussion is poor. Please consider citing more relevant references to make a comprehensive discussion.
9. Line 256 – 257: The conclusion “the scrimber exhibited greater fracture toughness than bamboo, showing a longer deformation and less damage to fiber and parenchymal cellswalls” is derived from unfair methodology because the products specimens were made from twice amount of raw material than the bamboo specimens.
Author Response
Please see the attachment
Author Response File: 
Author Response.pdf
Reviewer 2 Report (Previous Reviewer 2)
Dear authors,
General remark:
- What exists and has been completed in this research represents a good part of a work, but insufficient to be considered "Article".
- This research is at the level of a "Short communication", it cannot be considered an "Article". Massive additions to the work are needed to bring it to the required level.
- With the exposed additions, the paper will exceed 15 pages and will approach the level of an Article-type research paper.
Particular remarks:
1. No reference has a Digital Object indicator (DOI), in order to have access to the respective document.
2. At reference no. 4, two papers were passed and reference no. 8 is doubled.
3. A good part of the references is not written according to the instructions of the journal Forests.
4. Of the 24-25 bibliographic references, only a few refer to “scrimber”, others refer to wood fibre boards, and most to the properties of bamboo wood.
5. Since this "scrimber" is a new engineering product, which is not yet obtained at industrial level, a similar product such as LVL, Glulam, or another similar composite product must be compared. An additional bibliography is needed in this field.
6. The introductory chapter refers only to bamboo wood; no reference is presented about the "scrimber" composite or other similar composites. It is recommended to complete the introduction chapter with these data.
7. Line 59: “Phyllostachys pubescens”. The botanical name of the woody species is written in italics.
8. Line 60: “The culm”. This term is unusual one and must be explained.
9. Line 106. Here it is necessary to present the statistical methodology for data analysis, with at least the arithmetic mean and standard deviation (an ANOVA analysis would greatly raise the level of research). The results of this analysis must also be presented in the discussion or results chapter.
10. Line 237: The "Discussions" chapter needs to be massively completed. It is necessary to compare the values obtained with data from the specialized literature, for each analysed parameter. There is also a need for a centralizing table of the properties obtained in the research so that the reader can get an idea of how these values stack up against those obtained by other authors.
11. Line 287. References must be completed up to a level of over 35.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Reviewer 3 Report (Previous Reviewer 3)
The text, after many corrections, gained high readability.
However, despite the corrections, there are still grammatical errors and typos in the text (lines 109, 121, 126, 238, 257, 263 etc.).
Latin names should be in italics.
What was the final moisture content of bamboo?
The data in Figure 5 shows that the force was greater than in the description above the figure.
Line 170, there is no Fig. 5B.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report (Previous Reviewer 1)
Dear Editor of Forests
Thank you very much for inviting me to review the revised manuscript “In situ detection of the flexural fracture behaviors of Scrimber with inner and outer bamboo.” The authors have responded to our comments, but their responses did not sufficiently answer most of them. I am still unsatisfied with the manuscript, mainly because there is no addition in the cited reference to improve the discussion. The scrimber definition disagrees with their specimen. The cited patent CN103182727A “Hollow recombined bamboo and manufacturing method thereof” did not name the recombined bamboo product as a scrimber. Still, the authors insist on falsely stating their specimen as a scrimber. My detailed comments are below.
Best Regards
Reviewer
1. Line 1: “Title”. The term “Scrimber” disagrees with their specimens. Their specimens were made from bamboo strips. Bamboo scrimber is a fiber-based composite made from crushed bamboo fiber (zephyr). [https://doi.org/10.1186/s10086-019-1806-4 and https://doi.org/10.3390/f14010146]. Please find the correct terms for your specimens.
Answer: Thanks for your detailed comments. The purpose of fluffing/crushing process is to increase the resin penetration path. In this study, extremely thin bamboo strips were used to increase the penetration path of resin without destroying the structure of bamboo. Meanwhile, the scrimber were prepared by strips referenced in CN103182727 A.
Reviewer comment to the author’s response:
The Patent document CN103182727 A “Hollow recombined bamboo and manufacturing method thereof,” did not name their recombined bamboo product as a scrimber. The authors also did not cite the patent in the reference. Please consider finding the best-fit term for your specimen.
2. Line 28: “Bamboo is … ,…., and the highest-yielding natural material on Earth” The statement “Bamboo is the highest-yielding natural material on Earth” is an exaggerated claim without solid justification. Many other organisms yield more natural material than bamboo on earth (such as grass, corn, rice, bean, kernel, wheat, other agricultural plants, livestock, animal farms, and fisheries). The cited reference (Lugt et al., 2006 https://doi.org/10.1016/j.conbuildmat.2005.02.023) did not have contents of that statement. Please be more careful when making a claim.
Answer: Bamboo is a biodegradable, rapidly renewable, and high-yielding natural material on earth.
Reviewer comment to the author’s response:
Ok.
3. Line 31: “However, the bamboo is …….and the quality do not meet the requirements of wood construction, which do not used as engineered building materials.” The statement “Bamboo quality do not meet the requirements of wood construction, which do not used as engineered building materials” is a serious accusation that opposes the indisputable fact. Bamboo has been used as a construction material since ancient times until today. Many fascinating green buildings are built using round bamboo as their primary structural member. The recent development also justifies the reliability of the structural grade of bamboo, and the international building code for bamboo construction, such as ISO 22156:2021, is also available.
Please consider these statements:
Bamboo is also used in the paper, food and evidently in the building industry. Especially for the less wealthy population in tropical areas, bamboo plays a very important role in daily lives (shelter, employment, income, fuel, etc.). Recently, bamboo has also found more applications in the West, in industrial applications as well as in temporary structures. The favourable environmental performance of the bamboo culm has two distinct causes. First, its natural hollow design is structurally far more efficient than a rectangular massive section, e.g., in case of timber. This means that, in comparison with steel, concrete and timber, for a certain load-bearing capacity, bamboo contains less material mass. The second cause is the simple, short production process of bamboo (sawing, removal of branches, preservation, drying). Since problems related to the shape and irregularity of bamboo are inherent to its natural character, they can only be diminished, not completely avoided. Laminating bamboo for rectangular products will diminish problems caused by the shape, however, the study presented demonstrated a relatively great increase of environmental load in that case. [https://doi.org/10.1016/j.conbuildmat.2005.02.023].
Bamboo is a feasible alternative in design and civil construction to alleviate the excessive use of steel, concrete, oil byproducts, and timber and to reduce the logging of the forest. The talented architects design sustainable bamboo buildings in an aesthetically pleasing and cost-competitive for humanitarian projects around the world [i.e., the green school in Bali (Indonesia), Bamboo Pavilion in Chongming (China), dubbed Cubo housing units in Manila (Philipines), and sustainable ecological village in the Amazon (Brazil)]. Round bamboo has been traditionally applied for building structural components (i.e., flooring, walls, roofing, concrete reinforcement, and scaffolding) with substantial environmental benefits. Traditional bamboo construction technology has become a part of the community’s socio-culture; therefore, reviving, advancing, and disseminating such traditional technology to the people can strengthen the self-reliance of local communities. [https://doi.org/10.1016/j.rineng.2023.100911].
ISO 22156:2021 applies to the design of bamboo structures whose primary load-bearing structure is made of round bamboo or shear panel systems in which the framing members are made from round bamboo. It permits the construction design of a bamboo structure following ASD (allowable stress design), ACD (allowable load-bearing capacity design), or combined. ISO 22156:2021 also recognizes the PSFD (partial safety factor design) or LRFD (load and resistance factor design). [https://doi.org/10.1007/978-981-19-9327-5_9].
Answer：Tanks for your detailed comments and it is a great honor for me to receive your comments. Since the purpose of this study is to emphasize the influence of components in bamboo on mechanical properties, the statements are as follows:
Compared to wood, bamboo exhibits remarkable mechanical strength and fracture toughness and the round bamboo has been traditionally used in the building industry such as flooring, roofing, walls and scaffolding. However, the bamboo is highly variable in mechanical properties owing to its hollow structure.
Reviewer comment to the author’s response:
Please consider making a fair comparison, including the strengths and weaknesses of round bamboo compared to the engineered products. The above references discussed the advantages of round bamboo for construction material and the disadvantage of laminated bamboo, which contrasts with your introduction. Please cite those highly influential references to improve the discussion.
4. Line 73 – 75: Please state how much is the pressure (in the MPa unit) when conducting the hot press. Since the four plies of 1 mm layers are composed to make a 2 mm thickness of a specimen, there shall be a densification mechanism. Please consider discussing these densification results, including density, moisture content, and specific gravity of both bamboo and the products.
Answer: Four oven-dried resin-impregnated specimens of each part were parallel glued and pressed at 150 ℃ under 3 MPa to obtain scrimber with a dimension of 100 (l)×10 (t)×2 (r) mm3 (Fig. 1C) and the density of scrimber is 1.10-1.15 g/cm3. The specimens were kept in an environment of 60% relative humidity and a conditioning chamber to EMC of 10%-12%.
Reviewer comment to the author’s response:
Please also discuss the control (bamboo) specimen's physical properties and compare them to the products. The authors shall analyze the densification results of bamboo raw material.
5. Line 82 – 83: “30 (l)×2 (t)×2 (r) mm3.” Line 91: “5 (l)×2 (t)×2 (r) mm3” It is unfair to compare the densified products and the raw material’s mechanical properties using the same dimension of specimens because they are made from different amounts of raw material. A 5 (l)×2 (t)×2 (r) mm3 of the densified products was made from 5 (l)×2 (t)×4 (r) mm3 of the raw bamboo. Please consider comparing the 5 (l)×2 (t)×4 (r) mm3 raw bamboo specimen with the 5 (l)×2 (t)×2 (r) mm3 densified products.
Answer：It is to compare their morphology characterization in line 91.
Reviewer comment to the author’s response:
The authors insufficiently responded to our previous comment. They need to address it. Figures 2 and 5 indicated this unfair comparison.
6. Line 112 – 195: “The bending force in scrimber was ~50 N, which was higher than that of bamboo. Figure 2, and Figure 5.” This data was obtained from an unfair comparison. Please consider comparing the same amount of raw material. The raw bamboo material’s thickness shall be 4 mm to make a fair comparison with the 2 mm thickness of densified products because hot press densified 4 mm bamboo to become 2 mm products.
Answer：In this study, the density of products is the comparison factor and the thickness of samples is same to get the microscopic pictures with equal precision. Meanwhile, 4 mm is too thick to use in the in situ mechanical tests.
Reviewer comment to the author’s response:
If the density of products becomes the comparison factor, it shall be measured and analyzed. The manuscript did not report the control (bamboo) specimen’s density. If 4 mm is too thick to use in the in situ mechanical test, the products specimen thickness can be thinner (1 mm) to compare with the 2 mm thickness of the non-densified control specimen.
7. Line 234 – 235: Figure 8. The graph of modulus coincide with hardness; thus, they are hard to read. Please consider adding a small horizontal space between modulus and hardness line.
Answer:
Reviewer comment to the author’s response:
The graph of modulus still coincide with hardness and hard to read. Please adding a tiny horizontal space to avoid the coinciding error line.
8. Subchapter 4. The discussion is poor. Please consider citing more relevant references to make a comprehensive discussion.
Answer: Bamboo scrimber are prepared by bonding bamboo trips with PF resin, which show well quality and strength comparing with the natural bamboo. A lot of attempts have been made to illustrate that the preparation and physical mechanical properties of bamboo scrimber. While, very few researches focused on the improvement mechanism within bamboo scrimber, especially at the cellular level. The excellent fracture toughness of bamboo-based panels is highly attributed to the hierarchical structure of bamboo. To get an understanding of the fracture behavior and process with the structural components, we performed an in situ bending tests on the scrimber made of thin inner and outer bamboo strips in this work. As shown in a serious of in situ bending tests, the bamboo scrimber exhibited distinct asymmetric cracks propagation manners induced by the fiber and parenchymal cells. The load-displacement curves revealed that bamboo scrimber prepared of inner and outer bamboo owned higher fracture load than that of natural bamboo. The cracks propagation behaviors in bamboo scrimber from inner bamboo showed that cracks generally occurred in the ML layer and PF resin, which caused peeling the parenchymal cells and tearing the PF resin. Cracks propagation behaviors within scrimber made of out-er bamboo showed that the fiber bundles played an important role in restraining crack propagation, acting as crack stoppers. In situ bending tests and the SEM micro-images illustrated the fracture toughness attributed to the higher fiber density and PF resin cross-link with cell wall in fiber cells and parenchymal cells. The nanoindentation characterization was conducted on cell wall layer and ML layer in fiber cell and parenchymal cell. The storage in the fiber cells (s2: 27 GPa, s1: 24 GPa, ML: 18 GPa) and (s: 15 GPa, ML: 13 GPa) parenchymal cells within scrimber exhibited higher values compared to the natural bamboo. We confirmed that fibers were indeed the strongest phase and ML was compara-tively weaker, while PF resin improved the mechanical properties of cell wall layers in bamboo. By learning from the cellular structure of scrimber during real-time bending de-formation, it is possible to reveal the structureproperty relationships of scrimber and could be helpful in the understanding and designing the advanced biological composites
Reviewer comment to the author’s response:
The authors have added some discussions; however, there is no any additional citation and references. Please enrich the discussion chapter with some relevant and influential references.
9. Line 256 – 257: The conclusion “the scrimber exhibited greater fracture toughness than bamboo, showing a longer deformation and less damage to fiber and parenchymal cellswalls” is derived from unfair methodology because the products specimens were made from twice amount of raw material than the bamboo specimens.
Answer: In this study, the density of products is the comparison factor and the thickness of samples is same to get the microscopic pictures with equal precision. Meanwhile, 4 mm is too thick to use in the in situ mechanical tests.
Reviewer comment to the author’s response:
If the density of products becomes the comparison factor, it shall be measured and analyzed. The manuscript did not report the control (bamboo) specimen’s density. If 4 mm is too thick to use in the in situ mechanical test, the products specimen thickness can be thinner (1 mm) to compare with the 2 mm thickness of the non-densified control specimen.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 2 Report (Previous Reviewer 2)
Dear authors,
- - Your research has been completed, but not improved;
- The discussion chapter remained at the same stage, there is no comparison between your data and those of other authors;
- No DOI was entered on the references. The template says clearly and textually "Include the digital object identifier (DOI) for all references where available".
- There are still references with the non-abbreviated journal title, Example reference number 2 and 7.
- The work remained at the same level of "short communication"
- From my point of view, the work is not publishable, but I offer you a chance to improve it on the last hundred meters until publication. That is if you want this.
Good luck with that,
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
Reviewer’s Comments of The Manuscripts
Title : In situ detection of the fracture behavior of bamboo plywood under flexural bending
Manuscript ID : forests-2163447
Dear Editor,
Thank you very much for your invitation to review the manuscript "In situ detection of the fracture behavior of bamboo plywood under flexural bending." The manuscript is hard to read because the authors use unusual word terms to define some well-known things in Forests Products. Plywood, described in the dictionary as "a type of strong thin wooden board consisting of two or more layers glued and pressed together with the direction of the grain alternating," is used by the author to define their products in which the direction of the grain are not arranged alternatingly, but parallel. We suggest replacing the term bamboo plywood with parallel laminated bamboo (PLB). The English language could be better and extensive editing shall be done. However, the manuscript topic is engaging.
Best Regards
Reviewer.
Line 2-3: “Title”: The term “bamboo plywood” disagrees with the specimen. Plywood is a panel consisting of three or more veneer layers glued and pressed together with the direction of the grain alternating. Meanwhile, their specimens were made from several layers with the parallel grain direction. Please consider replacing the term bamboo plywood with parallel laminated bamboo (PLB).
Line 8-9: Please consider this rephrasing for clarity: “This paper investigates the fracture toughness and enhancement mechanism for each component in parallel laminated bamboo (PLB) at the cellular level.”
Line 10: The plural verb “were” disagrees with singular subject “behavior.” Please consider this active voice rephrasing: “In situ characterization techniques identified the fracture behavior of PLB in three-point bending tests, and scanning electron microscope (SEM) further visualized the cracks propagation of the fracture surface.”
Line 13: ”at cellular level” needs an article. Please consider adding the article: ”at the cellular level”
Line 13-14: Please consider this rephrasing for clarity: “Our in-situ results showed that the PLB exhibited a more extended deformation and higher bending load-bearing capacity than bamboo strand.”
Line 16-17: I don’t understand the author’s meaning with this statement. The sentence is hard to read. Please consider rephrasing it by using usual terms.
Line 19: Please consider this words reordering: “a weak mechanical interface in bamboo plywood”
Line 20-21: “parenchymal cell” shall be plural: “parenchymal cells”
Line 21: “with cell wall” is missing a determiner and shall be plural: “with the cell walls”.
Line 21: The verb form “were” disagrees with the singular subject “The crosslink”. Please consider replacing the singular subject with the plural one: “The crosslinks”.
Line 23-24: “Keyword” Please consider ascendingly sorting the keywords according to its first alphabet.
Line 27-28: “biodegradable, rapidly renewable and the highest yielding materials” needs a comma before “and”, a hyphen between highest and yielding, and “materials” singular form: ‘biodegradable, rapidly renewable, and the highest-yielding material”
Line 29-31: “However, the bamboo is highly variable in mechanical properties and the quality do not meet the requirements of wood construction, which do not used as engineered building materials”. I hardly disagree with this statement. Bamboo has been used as a construction material since ancient times until today. Many fascinating green buildings are built using round bamboo as their primary structural member. The recent development also justifies the reliability of the structural grade of bamboo, and the international building code for bamboo construction, such as ISO 22156:2021, is also available. Please consider reading these articles relating the round bamboo as construction materials.
http://dx.doi.org/10.1016/j.cscm.2021.e00516
Line 33: “While, “ The comma is unnecessary. Please delete it. Please also considering this rephrasing for clarity: “Bamboo is a natural functional hierarchical structure material composed of orientated stiff fibers and soft parenchyma matrixes.”
Lines 36 and 47:”, however” Please consider replacing the comma with a semicolon and adding a comma after however: ”; however, ”
Line 38: “with tiny lumen and the” need an article before tiny lumen and a comma before the. Please consider this rewording: “with tiny lumens, and the” or “with the tiny lumen, and the”
Line 39-41: Please consider this rephrasing: “Getting a deep study on the improvement mechanism of different components in the bamboo-based panel could help design biomimetic polymeric composites.”
Line 43: “of hierarchical structure” needs a determiner: “of the hierarchical structure”
Line 44: “the assist” the word form is not suitable. Please consider replacing the word form: “the assistance”
Line 44: “at cellular level” needs a determiner: “at the cellular level”
Line 47: “the oriented stiff fibers” seems in wrong order. Please consider reordering it: “the stiff oriented fibers”
Line 50-51: I don't understand the authors' meaning of this sentence "To preserve the morphology of fibers and parenchymal cells, the bamboo plywood was prepared by the inside and outside bamboo, and glued in grain." Please consider explaining it.
Line 53: “the fracture behavior for bamboo plywood”. The preposition “of” is incorrect here. Please consider this rephrasing: “the fracture behavior of PLB”.
Line 56: “at cellular level” needs a determiner. Please consider adding a determiner: “at the cellular level”
Line 66: “the Fig. 1A”. Determiner “the” is unnecessary. Please consider deleting it: “Fig. 1A”
Line 66-68: Please consider this rephrasing: “Bamboo was sliced into two pieces of ~1mm thickness strands from the inner and outer parts (Fig.1B) to prepare the PLB made from the different zone of the bamboo-portion.”
Line 68-76: The strand thickness is 1mm, 4 strands (layers) were parallel glued, and the PLB thickness is 2mm. Please consider explaining this confusing case. Is the PLB thickness 4mm or 2 mm?
Line 73-74: “To gain an overview of the deformation of each component in the bamboo plywood,” is a dangling modifier. It seems unnecessary. Please deleting it. “Four oven-dried resin-impregnated specimens of each part were parallel glued and pressed at 150 ℃ under a hot press to obtain PLB with a dimension of 100(l)×10(t)×2(r) mm3 (Fig.1C).”
Line 86: “real time” needs a hyphen. Please consider adding it: “real-time”
Line 92-93: “Five specimens with a dimension of 5(l)×2 (t)×2(r) mm3 were gold” is confusing. The specimen were not golds, they were gold platted. Please consider this rephrasing: “Five specimens with a dimension of 5(l)×2 (t)×2(r) mm3 were platted with gold, and the SEM acceleration voltage was 10kV.”
Line 99-101: Please consider this rephrasing: The nanoindentation and dynamic modulus maps tests (Hysitron TI 980 TriboIndenter, Bruker, Germany) measured the mechanical properties of the cell walls.
Line 101: “size of” needs an indenter: “a size of”; “mm3were” needs a space: “mm3 were”
Line 103: “at constant load” needs an indenter: “at a constant load”. Please consider this rephrasing for clarity: The indenter tip was loaded to a 10 mN peak at a 20 uN·s-1 rate and then held at a constant load for 5s.
Line 106: “microscopy imagines” seems incorrect. Please consider replacing the word: “microscopy images”
Line 105-107: Please consider this rephrasing:” After indentation, the in-situ scanning probe microscopy images observed the indents' position and morphological characteristics.”
Figure 2: Please merge the Figs 2A and 2B to compare both specimens’ load-displacement curves. Please explain those very different curves.
Line 117:”that of the bamboo” seems that there is an article usage problem here. Please consider deleting the article “the”: ”that of bamboo”
Line 117: “A serious of SEM imagines” seems incorrect. Is it a typo? I think it shall be “A series of SEM images”. Please confirm. Please consider this active voice rephrasing: “Fig.3 shows a series of SEM images corresponding to the bending strain detected in situ.”
Line 113-131: This paragraph contains many hard-to-read sentence. I do not understand the author’s meaning.
Recommendation:
I gave up on continuing to review this article because most of the sentences were difficult to understand. I recommend the authors to make extensive English editing and find a forest products technology expert to help them conform their word-term.
Reviewer 2 Report
1 Dear authors, Here is my observations.
Title: “…flexural bending”. The two words represent almost the same thing. I recommend using the expression "flexural strength", or “bending strength”.
2. Line 22: A last sentence of the abstract must be added to express a general conclusion on the research carried out.
3. Line 48. There is no reference regarding the plywood. This area must be completed with at least 10 new references, related to bamboo plywood.
4. Line 74. “…4 oven-dried resin-impregnated specimens”. Usually, a plywood is made up of an odd number (3, 5, 7...) of layers. You must explain why the general principle of making a plywood was not respected. Also, the arrangement of these veneers had to be perpendicular, and in the work, it seems to be parallel.
5. Lines 216-228. The discussion part must be more elaborated, especially after the introduction of new references about plywood, with which research results will be compared. Also, the originality of the research will be highlighted, namely that of the "in situ" testing of the plywood that was carried out.
6. Line 230-240. The conclusions must be rearranged. For the highlighting of each separate conclusion, it is recommended that each conclusion to have a new paragraph.
7. Line 255-276. References must be completed, otherwise the entire research would remain at the level of a "short communication"
8. The entire paper must be revised from the point of view of spelling, for example there are paragraphs with left alignment and others justify, and the citation of figures in the text is not appropriate.
Reviewer 3 Report
Please explain at least in one place the meaning of the abbreviation PF.
What type of probe was used for nanoindentation? No contact area or shape of the contact area can be seen in Fig 8.
By "elongation", do you mean "deflection"? When bending, the measure of strain is the deflection arrow.
Did the 30 mm length sample have a deformation of 14 mm? (Fig.5)
