Study on the drop impact characteristics and impact damage mechanism of sweet potato tubers during harvest

Collision of falling in the mechanical harvesting process of sweet potato is one of the main causes of epidermal destruction and damage to sweet potato tubers. Therefore, a sweet potato mechanical characteristic test and a full-factor sweet potato drop test were designed. Based on the analysis of the fitting mathematical model, the impact of the drop height, collision material and sweet potato chunk size on the damage of the sweet potato were studied. The mathematical models were established by fitting analysis of the IBM SPSS Statistics 22 software between the drop height and the sweet potato chunk size with each test index (impact force, impact stress, broken skin area and damaged area). The critical epidermal destruction height and the critical damage height of a certain size of sweet potato when it collides with a collision material can be calculated by the mathematical model, and the critical epidermal destruction mass and critical damage mass of sweet potato when it falls from a certain height and collides with a collision material can also be calculated. Then a series of critical values (including critical epidermal destruction force value, critical epidermal destruction impact stress, critical damage force value, critical damage impact stress) of mechanical properties of sweet potato were obtained. The results show that the impact deformation of sweet potato includes both elastic and plastic ones, and has similar stress relaxation characteristics. The critical damage impact stress of sweet potato is that the average value of the impact stress on the contact surface is less than it’s Firmness. The results provided a theoretical basis for understanding the collision damage mechanism of sweet potato and how to reduce the damage during harvest.

Finite Element Analysis and Experiment of the Bruise Behavior of Carrot under Impact Loading

Root–stem separating is one of the most important processes in carrot harvesting, but it is easy to cause damage due to the impact. In order to reduce the damage of carrot harvesting and provide the basis for the design of the separation mechanism, the damage mechanism of carrot was studied by the finite element method (FEM) and pendulum experiment in this study. Through the simulation analysis and the pendulum experiment, it was found that the critical damage impact force was 45.2 N and 43.1 N, respectively. Comparing the two results, the critical impact force of the carrot was basically the same, with an error of 4.87%. In conclusion, the FEM was reliable for the carrot damage prediction, and the critical impact force could be used for the design of a carrot harvesting mechanism.

A Study on the Derivation Method of Damage Range to Determine Reaction in Trichlorosilane Leak Accidents

In this study, we aimed to derive a formula for calculating the damage impact range using KORA, in the event of an accidental leakage of trichlorosilane (TCS), with simple information on the site to swiftly inform the decision to evacuate residents. TCS release rate, temperature, and dike height were selected as the variables, and an equation to calculate the damage impact range was derived through the regression analysis of the range using KORA. Based on the result it was seen that the damage range in the absence of dike has high correlation (p<0.05) in the order of TCS release rate and temperature, with an explanatory power of about 97%. The damage impact range in the presence of dike was found to have high correlation (p<0.05) to TCS release rate, dike height, and temperature, respectively, with an explanatory power of about 92~93%.

Cumulative damage impact of plant parasitic nematodes in smallholder maize cropping systems in East Africa.

This chapter focuses on the economic importance, damage symptoms, cumulative damage impact and some recommended integrated nematode management programmes of plant parasitic nematodes in smallholder maize cropping systems in East Africa. Information on the various improvements in the current nematode management methods and recommendations for future research are also discussed.