The Positive and Negative Synergistic Airflow-Type Jujube Fruit Harvester (P-N JH)

Round 1

Reviewer 1 Report

The paper presents an interesting study on harvesting of air-suctioned dates, demonstrating how a novel Positive and Negative Synergistic Airflow-Type harvester can be used to significantly improve the efficiency of the process.

1. The paper is generally clear and well written, however it would benefit from proof-reading. There are a few spelling and grammar mistakes, some examples are:

a) line 21: ... dates, It also ...

b) line 53: ... there are resulting in some ...

c) line 63: ... which are pick jujube fruit ...

but these are spread in the entire paper

2) To improve clarity, it would be good to have one sentence, at the end of the introduction, telling what is expected out of the P-N approach and why it should perform better than existing systems

3) Line 85-86: the title graphics is really poor. Adding some space might help, as well as having larger font size for sections (2.2) compared to subsections (2.2.1).

4) When describing the metrics (line 160 to 170) it would be good to have a reference for existing methods. This would benchmark the results that are shown later.

5) line 177: ... affects the migration characteristics of jujube fruit: not clear what "migration characteristics" means

6) Figure 3: caption should be underneath the figure, not in a new page. Latex should take care of this automatically though, not sure what is going on

7) Lines 283-285: issues in formatting

8) Eq. 5, 6 and 7: variables A, B, C seem to not be normalised. It is generally standard practice to instead do so, as after normalisation the magnitude of the coefficients gives a pretty good indication of the importance of each term. In this case it is instead mainly driven by the choice of units for the variables

9) I don't think the use of 3D plots is a good choice. By using colors it is already clear if the metrics displayed are higher or lower and adding a 3D perspective only make these plots more confusing and harder to read when they are explained. A 2D square colored by the output metric would contain the same information and be much easier to read.

10) In par. 3.4 the optimisation is discussed. But this is a multi-objective optimisation. What is the objective function? Is it a combination of the three metrics with a weight for each? Or is there a Pareto front, from which the optimum was picked? This is not clear.

11) Not sure I understand why looking at Table 4, the first point, for which the metrics read 99.55, 1.86, 0.66 should not be better than the optimum from 3.4, for which the pickup rate is lower (99.29) the impurity rate is higher (2.02) and the damage rate as well (1.03). Why the optimiser converged to something worse (in all metrics!) than one of the experimental points?

12) The actual performance at that point are very different from what was predicted. Saying that the error in pickup rate is 2.09% (line 386) is actually hiding the truth. The model predicted that 0.7% of fruits would not be picked up, the reality is that 2.8% are not picked up. That is 4 times more fruits on the ground. Actually 97.21 pick up rate is worse than any other experimental point. This is definitely not a good prediction for an optimiser.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

In this paper the authors present a novel machine for the jujube fruit harvesting. For this purpose, they introduce a design for the machine whose performance is check later under real conditions, obtaining a high performance. This work is interesting but it is necessary to introduce some changes before publishing to make the work clearer.

Line 77: The shown values for the diameters of jujube fruit used in the experiments are obtained by the average of several fruits and the error is an standard deviation? Please, specify.

Line 83: Here you say that you use a pressure anemometer which allows you to measuring in a range 0±3 000 Pa, what that the ± sign means here? It means that you can measure from 0 Pa to 3000 Pa in two opposite directions?

Moreover, you say your anemometer measures pressure, however, in the experiments you always show flow velocities. How do you measure these velocities? Do you use an alternative measuring method or you calculated the velocity from that pressure? Please, specify it.

Section 2.2.2.: Your device works thanks to the flow rate it generates either inside and outside its mouth. Have you measured, simulated or calculated the flow profile caused by your device? Please consider including a graph showing the flow profile inside and outside the device, since it will make easier the understanding of this work.

Section 2.3.: How do you define the impurities? Are any “big” object that is pick up by your machine (e.g. stones, leaves…) or do you also consider “small” objects (e.g. sand grains, dust…)? Please, specify.

Section 2.4.: The experiment needs a better description, please consider the following points to include in the next version of the paper.

-          How do you measure the airflow velocity and at which point? Please, keep in mind that these velocities should be different depending on the position.

-          How do you measure the travel speed?

-          You study your pick up, impurities and damage rate as a function of the positive and negative airflow as well as a function of the travel speed. However, travel speed depends directly on the airflows, isn’t it? If it is, then all the regression analysis can be simplified since one variable can be eliminated. Moreover, if travel speed is a dependent variable it will be interesting including a graph to show the dependence of this parameters with the independent variables (i.e. P and N airflows).

-          Do the indexes studied in your experiments actually depends on P & N airflows or they just depend on travel speed? If yes, all the analysis could be really simplified since there will be just one independent variable in the experiment (travel speed) making more easy the analysis.

-          Table 3: Please give a definition of what are the levels in shown in this table.

Section 3:

-          What is the reason why you make a fit to this polynomial function? Does it have any physical meaning or just you found phenomenologically that it fits well? Please, specify in this in the manuscript.

-          What method have you used for the regression analysis? Is least squares method or is it other? Please, specify.

-          Figures 3, 4 & 5: Please, consider the possibility of including the experimental points in these graphs so as the validity of the regression analysis can be check at a glance. Moreover, if the travel speed can be considered as a dependent variable of P & N airflows, graphs b and c are redundant.

Section 4: Could your device be used for harvesting other fruits, or it is limited to jujube fruit?

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Dear authors,

I really appreciate your answers to my questions. I honestly consider you have submitted a good work. And I consider your work is worth to be published.

Best regards