Some Methods for the Degradation-Fragility Degree Determination and for the Consolidation of Treatments with Paraloid B72 of Wood Panels from Icon-Type Heritage Objects
Round 1
Reviewer 1 Report
Review of article for the journal Forests - MDPI
Manuscript Number: forests-1703260
Article submitted: 19 April 2022 (20 p.)
Title of the manuscript (Article):
Four evaluation methods for the degradation-fragility degree and for the consolidation treatments of wood panels from heritage objects type icons
Authors:
Avram, A., Ionescu, C. S., Lunguleasa, A.
________________________________________________________________________________
The manuscript compares effectiveness of four methods for the determination of insect-damage degrees in five icons made from lime wood (Tillia cordata). Simultaneously – in addition, it touches on the issue of the effect of a conservation acrylic substance Paraloid B72 on the Brinell and Mark hardness values of undamaged and insect-damaged lime wood specimens.
I have these remarks and recommendations:
TITLE (Note:) Consolidation treatments of wood with Paraloid B72 were compared by two “hardness” methods.
1. Introduction
- This part is too widespread – it often describes knowledge unrelated to the issue of the experimental work (e.g. degradation of wood by decaying fungi; detail descriptions of wood conservation technologies with Paraloid B72).
- Lines 46-47: Generally is valid that “Durability = f (mainly of the type and amount of secondary chemicals, e.g. tannins and terpenoids)”. It means, that the sentence “… durability, but also on the content of secondary chemicals” have to be reformulated.
- Line 55, but also in some other lines: The “wood-eating” fungi don’t exist (it is wrong name) – because rot made wood-decaying which produce celullases, peroxidases and other enzymes which catalyse depolymerisation of cellulose, lignin and other structural components of cell walls in wood.
- Lines 56, 62, 213: The dry rot fungus is Serpula lacrymans (no Merulius lacrymans).
- Line 57: A negative temperature of – 38 °C is not convenient for growth of fungi (including C. puteana = for this species is optimal temperature 23 °C, and it is able to grow between 3 °C and 35 °C Þ See the Reference 10).
- Line 75: There should be “… and the relative humidity 55-95% (10).
- Line 78: Correctly should be “Xestobium rufovillosum”.
2. Materials and Methods
- Line 227: There should be given reference for the Eq. 1.
- Line 250: Correctly should be “Anobiidae”.
- Line 254: The ratio “3.89” is valid only for this experiment ?, and is valid for all 5 icons ?
- Line 277: Correctly should be “… diameter of flight holes, in mm”, i.e. no in mm2.
- Line 293: HBd (i.e., “d” in down index).
- Lines 294-306: Significance of these sentences is difficult to read – they should be better written.
- Line 313: 100 daN, ? There should be 100 N.
- Line 347: There should be “… of the tip penetrator, in mm2;” .
and 4. Results and Discussion
- Lines 361, 379: No “Gfp” but “Gfq” – see Eq. 3.
- Lines 369-373: These sentences belong to part 2. “Materials and Methods”.
- Line 414: Why was tested as well as other species O. pyramidale ?
- Line 416 and others: Why the effect of Paraloid B72 was searched only by hardness methods ? What retention (kg/m3) or WPG (%) values have been achieved for the tested specimens ?
- Line 487 – Table 3: Why for Icons No 3 and No 4 are not given Avg. values ?
- Line 496 – Figure 11: In the x –axis should be (N/mm2).
- Line 509: Is correct the number of diameter (1.4 ¸ 3.4 mm) for the flight hole ?
- Line 597 – Table 5: It is a very interesting and important part of the article. However, by my opinion, its scientific value could be higher if the fragility-degradation values will be make from correlation analyses between the four evaluation methods.
REFERENCES:
- There are some mistakes, e.g. (10) = correct name is “Reinprecht, L.” …. In Wood Deterioration, Protection and Maintenance. Wiley Blackwell, Chichester, UK, pp. 126-144. ISBN 978-1-119-10653-1.
Author Response
Reviewer 1
Thank to reviewer for suggestions and observations.
1. Reviewer: I have these remarks and recommendations: TITLE (Note:) Consolidation treatments of wood with Paraloid B72 were compared by two “hardness” methods.
Author answers: The title of the paper was changed, highlighting the use of Paraloid B72, as follows “Some methods for the degradation-fragility degree determination and for the consolidation treatments with Paraloid B72 of wood panels from icons type heritage objects”
2. Reviewer: Introduction. This part is too widespread – it often describes knowledge unrelated to the issue of the experimental work (e.g. degradation of wood by decaying fungi; detail descriptions of wood conservation technologies with Paraloid B72).
Author answers: Some changes were made to the issues reported and other paragraphs were deleted that were repeated from one author to another. On the other hand, with the introduction of the B72 consolidator in the title of the paper, a good part of the introduction became desirable.
3. Reviewer: Lines 46-47: Generally is valid that “Durability = f (mainly of the type and amount of secondary chemicals, e.g. tannins and terpenoids)”. It means, that the sentence “… durability, but also on the content of secondary chemicals” have to be reformulated.
Author answers: The specified phrase has been changed, by erasing “durability”.
4. Reviewer: Line 55, but also in some other lines: The “wood-eating” fungi don’t exist (it is wrong name) – because rot made wood-decaying which produce celullases, peroxidases and other enzymes which catalyse depolymerisation of cellulose, lignin and other structural components of cell walls in wood.
Author answers: The specified phrases have been replaced and completed, becoming: “wood decaying”.
5. Reviewer: Lines 56, 62, 213: The dry rot fungus is Serpula lacrymans (no Merulius lacrymans).
Author answers: The stipulated change has been made in the text and required pages.
6. Reviewer: Line 57: A negative temperature of – 38 °C is not convenient for growth of fungi (including C. puteana = for this species is optimal temperature 23 °C, and it is able to grow between 3 °C and 35 °C Þ See the Reference 10).
Author answers: The negative temperature specification has been deleted. Necessary adds were made, too.
7. Reviewer: Line 75: There should be “… and the relative humidity 55-95% (10).
Author answers: The requested completion has been made, extending range on 95%.
8. Reviewer: Line 78: Correctly should be “Xestobium rufovillosum”.
Author answers: The change was made in the paper.
9. Reviewer: Materials and Methods Line 227: There should be given reference for the Eq. 1.
Author answers: No reference was made to Equation (1), as it is a common equation in the subject disciplines for students, regarding the Physics of Wood.
10. Reviewer: Line 250: Correctly should be “Anobiidae”.
Author answers: The necessary change has been made, adding “i”.
11. Reviewer: Line 254: The ratio “3.89” is valid only for this experiment ?, and is valid for all 5 icons ?
Author answers: Several additions have been made regarding the calculation methodology of this coefficient, valid for all the research within the paper and within the equations in which this coefficient appears. “Initially, an area of the outer surface was coloured black and there was a color difference between the areas with holes and those without holes. The two surfaces were determined by color scanning. Then the outer part was excavated on the same surface, revealing the holes and inner galleries, much more complex than those on the surface. The surface was dyed black, with darker and lighter areas appearing. The area of the two areas was determined by scanning. The ratio between the 2 surfaces was made, obtaining the coefficient 3.89 for the 5 different surfaces taken into account.”
12. Reviewer: Line 277: Correctly should be “… diameter of flight holes, in mm”, i.e. no in mm2.
Author answers: The necessary change has been made.
13. Reviewer: Line 293: HBd (i.e., “d” in down index).
Author answers: "d" from Brinell hardness was passed as subscript value.
14. Reviewer: Lines 294-306: Significance of these sentences is difficult to read – they should be better written.
Author answers: These sentences have been simplified for a better understanding of the content.
15. Reviewer: Line 313: 100 daN, ? There should be 100 N.
Author answers: The necessary change has been made.
16. Reviewer: Line 347: There should be “… of the tip penetrator, in mm2;” .
Author answers: The necessary change has been made in the research text.
17. Reviewer: Results and Discussion, Lines 361, 379: No “Gfp” but “Gfq” – see Eq. 3.
Author answers: The necessary change has been made, namely it is replaced “p” with Greek symbol “ρ”.
18. Reviewer: Lines 369-373: These sentences belong to part 2. “Materials and Methods”.
Author answers: Those sentences were the last chapter on “Materials and Methods.
19. Reviewer: Line 414: Why was tested as well as other species O. pyramidale ?
Author answers: Balsa wood (Ochroma pyramidale or Ochroma lagopus) is one of the species used fragmentarily in restoration works to complete the losses, due to its very low density. Due to its density and strength, the balsa wood does not overload the damaged panel and does not create additional stresses. An adding was made in the text.
20. Reviewer: Line 416 and others: Why the effect of Paraloid B72 was searched only by hardness methods ? What retention (kg/m3) or WPG (%) values have been achieved for the tested specimens ?
Author answers: The Brinell Hardness test could not be applied to the 5 icons, as it would have led to their breakage or serious damage, which is why it was performed on new parts or damaged parts from the laboratory. “Consolidation retention was about 3%, by mass”.
21. Reviewer: Line 487 – Table 3: Why for Icons No 3 and No 4 are not given Avg. values ?
Author answers: The legend of the table has been completed in order to understand the abbreviations used. This “Avg” meant Average xylophagous damage, which meant an average degradation of the panels in terms of xylophagous degradation. These kind of degradations were taken from laboratory.
22. Reviewer: Line 496 – Figure 11: In the x –axis should be (N/mm2).
Author answers: The measurement unit N/mm^2 was put on the Ox axis.
23. Reviewer: Line 509: Is correct the number of diameter (1.4, 3.4 mm) for the flight hole?
Author answers: Necessary changes were made to the text, changing the comma to a full stop. In research, these values of 1.4 mm to 3.4 mm were values usually obtained by measurements.
24. Reviewer: Line 597 – Table 5: It is a very interesting and important part of the article. However, by my opinion, its scientific value could be higher if the fragility-degradation values will be make from correlation analyses between the four evaluation methods.
Author answers: The corelation analysis were made in the Discussion chapter, by introducing a new paragraph.
25. Reviewer: REFERENCES- There are some mistakes, e.g. (10) = correct name is “Reinprecht, L.” …. In Wood Deterioration, Protection and Maintenance. Wiley Blackwell, Chichester, UK, pp. 126-144. ISBN 978-1-119-10653-1.
26. Author answers: The requested change was made to the specified reference.
Authors
Reviewer 2 Report
Comments and Suggestions for Authors
In the present study of “Four evaluation methods for the degradation-fragility degree and for the consolidation treatments of wood panels from heritage objects type icons” four evaluation methods were carried out for assessing the deterioration state of wooden heritage objects. The subject of the presented article is very interesting and of significant importance for designing the technological flow regarding the preservation or conservation. However, the reason for applying B72 on consolidating the degraded specimens was not clearly or suitably stated. It would be better if the author can add some references stating the advantages of B72 compared to popular consolidants such as PEGs.
Given the “title” of this article, it is recommended that the authors clarify in their Introducation section why they chose these “four evaluation methods”, rather than devoting most of their space to introducing B72.
The discussion section needs to increase the interpretation of their experimental results, as well as the reference and comparative analysis of previous studies and reports.
Taking it all together, I regret to tell you that the manuscript in its present form is not ready for publication. I encourage the authors to rewrite the Introduction section and Discussion section and prepare a new version of the manuscript in line with the general comments given above and some minor which can be seen below:
1 Equation (1) does not apply to all moisture contents. Please add the moisture content “range” in line 228 and add the reference at the same time.
2 I understand that it is hard to pick a good reference woodchip, and the author did pick healthy wood as reference specimens as described in section 2.1(lines 216~219). However, the properties of such wood might differ a lot from the icons piece when it was freshly cut down 150~350 years ago. It would be better if the authors can say something about this limitation in the manuscript. Otherwise, directly quantitatively comparing the density/hardness seems not that accurate – overstatement somehow.
3 Equation 3 means the same thing as equation 2, and Eq. 3 does not significantly easier than Eq. 2. It seems that equation 3 is not necessary to appear in the article.
For Eq.5 it could be further simplified.
4 For the 2.2 section, considering that the radial and tangential sections of wood have different structures, the speed and degree of insect damage to different sections may not be the same. Does the "surface" mentioned in the article consider the anatomical direction? Please explain more about that.
What’s more, the “3.89” should be given more information in the text to explain how “3.89” was determined. Otherwise, the “3.89” could not be used in Eq. (4).
5 For the 2.3 section, do the authors consider the anatomical direction of the test surface? Please clarify in the text which section was tested- cross-section, tangential section, or radial section?
The quality of Figure 7 could be improved and it would be more easily understood by marking “1 to 5” in the right/second image.
6 The language, especially in the Figure titles, needs to be more scientific. For instance Figure 9, “Brinell hardness of new and old degraded lime specimens, treated and untreated B72” in line 438 is not formal for a scientific paper.
7 It would be nice if the names of woods with different degrees of degradation could be unified. For an instant, the slightly deteriorated lime can be unified as “slightly degraded lime” or “weak degraded lime”.
8 Please check the math notation in the Figures, especially in Figure 12.
Author Response
Reviewer 2
Thank to reviewer for suggestions and observations.
- Reviewer: In the present study of “Four evaluation methods for the degradation-fragility degree and for the consolidation treatments of wood panels from heritage objects type icons” four evaluation methods were carried out for assessing the deterioration state of wooden heritage objects. The subject of the presented article is very interesting and of significant importance for designing the technological flow regarding the preservation or conservation. However, the reason for applying B72 on consolidating the degraded specimens was not clearly or suitably stated. It would be better if the author can add some references stating the advantages of B72 compared to popular consolidants such as PEGs.
Author answers: The next phrase was introduced in the Introduction chapter. “One of the main advantages of B-72 as a consolidator is that it is stronger and harder than others without being extremely brittle. This consolidator is more flexible than many of the other typically used consolidators and tolerates more stress on a jointing. Along with Paraloid B72, another synthetic product used to strengthen the wood support is polyethylene glycol. However, the disadvantages of reduced penetration in the cell membrane for concentrations higher than 10%, lack of antibacterial properties, increased acidity of the treated product and reduced depth of penetration into the wood must be overcome”.
- Given the “title” of this article, it is recommended that the authors clarify in their Introducation section why they chose these “four evaluation methods”, rather than devoting most of their space to introducing B72.
Author answers: In order to introduce the B72, the title was changed accordingly: “Some methods for the degradation-fragility degree determination and for the consolidation treatments with Paraloid B72 of wood panels from icons type heritage objects”
- The discussion section needs to increase the interpretation of their experimental results, as well as the reference and comparative analysis of previous studies and reports.
Author answers: The discussion chapter has been extended, making several comparisons between one's own results and those of other authors. Also, a new comparison between degree of fragility and methods was made.
- Taking it all together, I regret to tell you that the manuscript in its present form is not ready for publication. I encourage the authors to rewrite the Introduction section and Discussion section and prepare a new version of the manuscript in line with the general comments given above and some minor which can be seen below:
Author answers: The two chapters of Introduction and Discussion have been rewritten.
- Equation (1) does not apply to all moisture contents. Please add the moisture content “range” in line 228 and add the reference at the same time.
Author answers: The equation is valid for moisture content below fibre saturation point (FSP), moisture content usually found in the restauration icon-type heritage objects. A supplement was introduced in this regard in the paper, line 237 “under fibre saturation point”. The relationship is well known and can be found in any "Physics of Wood" course for students.
- I understand that it is hard to pick a good reference woodchip, and the author did pick healthy wood as reference specimens as described in section 2.1(lines 216~219). However, the properties of such wood might differ a lot from the icons piece when it was freshly cut down 150~350 years ago. It would be better if the authors can say something about this limitation in the manuscript. Otherwise, directly quantitatively comparing the density/hardness seems not that accurate – overstatement somehow.
Author answers: At line 241, it is introduced the next paragraph: “The density of lime wood introduced into heritage objects 200 years ago is not precisely known and depends on the vegetation conditions of the tree and other biotic and abiotic factors. As there are no precise methods for evaluating it, it was considered the equivalence-approximation of density with that of the existing species (lime) to the required moisture content. Beyond these limitations, the assessment is within ± 5% of current statistical analyses”.
- Equation 3 means the same thing as equation 2, and Eq. 3 does not significantly easier than Eq. 2. It seems that equation 3 is not necessary to appear in the article. For Eq.5 it could be further simplified.
Author answers: Equation 3 was permanently deleted from the paper, and the other equations were renumbered. Equation 5 has been simplified.
- 4 For the 2.2 section, considering that the radial and tangential sections of wood have different structures, the speed and degree of insect damage to different sections may not be the same. Does the "surface" mentioned in the article consider the anatomical direction? Please explain more about that.
Author answers: Text “The faces of the new wood were tangential, the direction of action of the forces being the radial one.” Was introduced in the Method chapter
- What’s more, the “3.89” should be given more information in the text to explain how “3.89” was determined. Otherwise, the “3.89” could not be used in Eq. (4).
Author answers: “3.89” was replaced with coefficient “k”. Necessary explanation was introduced
Text „Initially, an area of the outer surface was colored black and there was a color difference between the areas with holes and those without holes. The two surfaces were determined by color scanning. Then the outer part was excavated on the same surface, revealing the holes and inner galleries, much more complex than those on the surface. The surface was dyed black, with darker and lighter areas appearing. The area of the two areas was determined by scanning. The ratio between the 2 surfaces was made, obtaining the coefficient 3.89 for the 5 different surfaces taken into account”.
- 5 For the 2.3 section, do the authors consider the anatomical direction of the test surface? Please clarify in the text which section was tested- cross-section, tangential section, or radial section?
Author answers: Tangential section, and the acting direction was radially. Necessary changes were put in text.
- The quality of Figure 7 could be improved and it would be more easily understood by marking “1 to 5” in the right/second image.
Author answers: The positions of the device parts were entered in Figure 7, on the right.
- 6 The language, especially in the Figure titles, needs to be more scientific. For instance Figure 9, “Brinell hardness of new and old degraded lime specimens, treated and untreated B72” in line 438 is not formal for a scientific paper.
Author answers: Title of Fig 9 was changed in “Brinell hardness of lime specimens”
- 7 It would be nice if the names of woods with different degrees of degradation could be unified. For an instant, the slightly deteriorated lime can be unified as “slightly degraded lime” or “weak degraded lime”.
Author answers: The words “slightly deteriorated lime” was changed in “slightly degraded lime”
- 8 Please check the math notation in the Figures, especially in Figure 12.
Author answers: Math notation in text of Figure 12 were changed. “-“ in loc de “÷”.
Authors
Round 2
Reviewer 1 Report
Review of article for the journal Forests - MDPI
Manuscript Number: forests-1703260-Revised Version
Article submitted: 09 May 2022 (20 p.)
Title of the manuscript (Article):
Some methods for the degradation-fragility degree determination and for the consolidation treatments with Paraloid B72 of wood panels from icon-type heritage objects
Authors:
Avram, A., Ionescu, C. S., Lunguleasa, A.
________________________________________________________________________________
The revised manuscript I can recommend for publication in the Forests MDPI journal.
09 May 2022 Reviewer
Comments for author File: 
Comments.pdf
Author Response
The work has been substantially improved. Particular attention was paid to the Introduction and Results chapter, where the reviewer considered that it could be improved. The following changes were made in the research:
- Line 36: Word "conducive" was transformed into "conducing".
- Lines 37, 368: Word "eating" was transformed into "decaying".
- Line 48: Word "to attack" was transformed into "to be attacked".
- Line 56: Word "can not" was transformed into "cannot".
- Line 73: Word “of” was introduced.
- Line 77: Word “can” was introduced.
- Line 129: Word “content” was added beside the “moisture” one.
- Line 186: Word "with" was changed with "and".
- Line 191: Word “and” was introduced
- Line 303: Fig 7 was aligned to the right.
- Line 363: Letter “x” was changed with “×”.
- Line 365: Abbreviation “Eq.” was introduced.
- Line 391: Word "growth" was transformed into "increase".
- Line 402: Word “the next” was introduced.
- Line 405: Word “usually” was introduced.
- Line 408: The group “(balsa and lime)” were introduced.
- Line 448: Word “the” was introduced.
- Line 482: Word "density" was transformed into "hardness".
- Lines 563, 564: Word "resistance" was transformed into "force".
Authors
Reviewer 2 Report
The article has been improved by the authors' modifications.
Author Response
Reviewer 2:
- Does the introduction provide sufficient background and include all relevant references? Can be improved.
- Are the results clearly presented? Can be improved.
Authors response:
The work has been substantially improved. Particular attention was paid to the Introduction and Results chapter, where the reviewer considered that it could be improved. The following changes were made in the research:
- Line 36: Word "conducive" was transformed into "conducing".
- Lines 37, 368: Word "eating" was transformed into "decaying".
- Line 48: Word "to attack" was transformed into "to be attacked".
- Line 56: Word "can not" was transformed into "cannot".
- Line 73: Word “of” was introduced.
- Line 77: Word “can” was introduced.
- Line 129: Word “content” was added beside the “moisture” one.
- Line 186: Word "with" was changed with "and".
- Line 191: Word “and” was introduced
- Line 303: Fig 7 was aligned to the right.
- Line 363: Letter “x” was changed with “×”.
- Line 365: Abbreviation “Eq.” was introduced.
- Line 391: Word "growth" was transformed into "increase".
- Line 402: Word “the next” was introduced.
- Line 405: Word “usually” was introduced.
- Line 408: The group “(balsa and lime)” were introduced.
- Line 448: Word “the” was introduced.
- Line 482: Word "density" was transformed into "hardness".
- Lines 563, 564: Word "resistance" was transformed into "force".
Authors
