Study on Performance of Concentric Threshing Device with Multi-Threshing Gaps for Rice Combines
Round 1
Reviewer 1 Report
Introduction
The Authors present detailed introduction, rich in bibliographic citations, very important for the development of the paper.
I would suggest deleting the last paragraph (line 77 to line 88)
Materials and Methods
No suggestions for the first two paragraphs, also well connected to bibliography.
On the contrary, in the field experiment (2.3) a sampling plan on threshed rice is missing and there is no reference to the absolute value (e.g. detailed informations about weight or volume) of the sample.
Furthermore, since this is a field experiment, in line 177 it would be appropriate to express the dimensions in meters.
Discussions
My suggestions is for the data of field experiment linked to the evaluation of the quality of threshed rice and summarized in Table 7: can the values be considered representative in the field test analyzes?
Conclusions
I have the same doubt expressed for the discussions
Author Response
Point 1: I would suggest deleting the last paragraph (line 77 to line 88).
Response 1: Thank you for your comments. We have deleted the last paragraph (line 77 to line 88) as you suggested.
Point 2: On the contrary, in the field experiment (2.3) a sampling plan on threshed rice is missing and there is no reference to the absolute value (e.g. detailed informations about weight or volume) of the sample.
Response 2:
Thank you for your comments. We mentioned that before the experiment, rice fields with basically the same crop growth were selected as the experiment area (Section 2.4.2). We have added the Physical properties of "Jia Hua" rice, as shown in Table 5. Line 161-163
Point 3: Furthermore, since this is a field experiment, in line 177 it would be appropriate to express the dimensions in meters.
Response 3: Thank you for your comments. We have modified the dimensions to be expressed in meters as you suggested. Line163-164
Point 4: My suggestions is for the data of field experiment linked to the evaluation of the quality of threshed rice and summarized in Table 7: can the values be considered representative in the field test analyzes?
Response 4: Thank you for your comments. The values are representative in the field test analyzes. The field test referred to China GB/T 8097-2008 Equipment for harvesting - Combine harvesters - Test procedures.
Reviewer 2 Report
The article is well done. It concerns the study of threshing rice. The great success of the authors is to conduct experiments and obtain the results of such research because they are difficult and labor-intensive research. Coaxial threshing equipment is interesting. Field research is also an undoubted success. I would like to point out to the authors that when researching the threshing and cleaning process, the most important thing is the shearer throughput and it would be advisable to clarify the research description for which group of combines they can be referred to and with which throughput in kg / s. In the literature review and citations, please mention the rotary cone cleaners. In the conclusions in lines 354 and 355, please clarify the statement - “more homogeneous mixture”. At the end of conclusions, add guidelines for further testing.
Author Response
Point 1: The article is well done. It concerns the study of threshing rice. The great success of the authors is to conduct experiments and obtain the results of such research because they are difficult and labor-intensive research. Coaxial threshing equipment is interesting. Field research is also an undoubted success. I would like to point out to the authors that when researching the threshing and cleaning process, the most important thing is the shearer throughput and it would be advisable to clarify the research description for which group of combines they can be referred to and with which throughput in kg / s. In the literature review and citations, please mention the rotary cone cleaners. In the conclusions in lines 354 and 355, please clarify the statement - “more homogeneous mixture”. At the end of conclusions, add guidelines for further testing.
Response 1: Thank you for your comments. We have added the feeding rate as you suggested, as shown in Table 6. In the literature review and citations, I did not mention the rotary cone cleaners because it does not significantly affect the integrity of the structure and content of this article. We have clarified the statement - “more homogeneous mixture” as you suggested, as shown in Conclusions (1) Line343-346. We have added guidelines for further testing at the end of conclusions Line350-353.
Author Response File: 
Author Response.docx
Reviewer 3 Report
General comments:
- Keywords consist only important terms, which are not mentioned in title nor abstract
- What was the contact model used for the DEM simulation?
- How did the authors evaluate the accuracy of the simulation model for practical application?
- The comparison between simulated and experimental results shall be made clear in the results&discussion
Specific remarks:
- Figure 1, 2 & 3 shall be merged
- Line 116 ==> Which EDEM version?
- Table 4 ==> How is it possible that the rolling friction coefficient is identic for all contact parameters?
- Line 240 ==> Please mention the time step and cell size determined for the simulation
- Figure 7, 8, 13 ==> Color legend shall be added
- Figure 14 ==> The numbers at the blue line inside the chart shall be described in the figure caption
Author Response
General comments:
Point 1: Keywords consist only important terms, which are not mentioned in title nor abstract.
Response 1: Thank you for your comments. The keywords are mentioned in title nor abstract.
Point 2: What was the contact model used for the DEM simulation?
Response 2: Thank you for your comments. In section 2.2.2, we mentioned that the discrete element model of rice grain and flexible straw established by Su et al. was adopted in this simulation. The grain contact force model adopted the DEM simulation was the Hertz-Mindlin (no slip) contact model. These particles of the straw were bonded using the Hertz-Mindlin with bonding model.
Point 3: How did the authors evaluate the accuracy of the simulation model for practical application?
Response 3: Thank you for your comments. The simulation model and simulation process referred to the article “Simulation of rice threshing performance with concentric and non-concentric threshing gaps”. Su et al. proved the accuracy of the simulation model for practical application.
Point 4: The comparison between simulated and experimental results shall be made clear in the results & discussion.
Response 4: In this paper, the circumferential distribution of rice mixture, the variation of total quantity and the average velocity of rice mixture were analyzed by discrete method. However, these properties are difficult to obtain relevant data in the actual experiment. Thence, there was no comparison between simulated and experimental results.
Specific remarks:
Point 1: Figure 1, 2 & 3 shall be merged.
Response 1: Thank you for your comments. After the discussion of our research group, we believed that the structure of the article will be clearer without merging.
Point 2: Line 116 ==> Which EDEM version?
Response 2: Thank you for your comments. We have added the EDEM version as you suggested， Line102.
Point 3: Table 3 ==> How is it possible that the rolling friction coefficient is identic for all contact parameters?
Response 3: Thank you for your comments. The rolling friction coefficient referred to the article “Simulation of rice threshing performance with concentric and non-concentric threshing gaps” Line135，Tab 4.
Point 4: Line 240 ==> Please mention the time step and cell size determined for the simulation.
Response 4: Thank you for your comments. We have added the cell size and time step as you suggested Line231-232.
Point 5: Figure 7, 8, 13 ==> Color legend shall be added.
Response 5: Thank you for your comments. We have added the color legend in Figures 7 and 8. The use of different colors in Figure 13 only added to the intuitiveness of the data analysis and had no special meaning, so no legend was added.
Point 6: Figure 14 ==> The numbers at the blue line inside the chart shall be described in the figure caption.
Response 6: Thank you for your comments. The numbers were the total loss rate of multi-threshing gaps of 10 mm and 15 mm, which was described in the figure caption， Line332-334
Author Response File: Author Response.docx
