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Understanding the biomechanical properties of safflowers is essential for appropriately designing harvesting machinery and optimizing the harvesting process. Safflower is a flexible crop that lacks a basis for relevant simulation parameters, which causes difficulties in designing harvesting machinery. In this study, a calibration method for safflowers was proposed. First, a discrete element model was established by measuring the intrinsic parameters of a safflower, such as its geometric parameters, density, Poisson's ratio, and modulus of elasticity. Second, the contact and bonding parameters were calibrated using a combination of physical and simulation tests. In the contact parameter tests, the Hertz-Mindlin (no-slip) model was implemented for the stacking angle tests conducted regarding the safflower filament. A regular two-level factorial design was used to determine the important factors and perform the steepest climb test. Moreover, the Box-Behnken design was adopted to obtain the optimal contact parameters. In the bonding parameter tests, the Hertz-Mindlin model with bonding contact was applied for the safflower shear simulation tests; moreover, the optimum bonding parameters were obtained through the central composite design test. The results demonstrated that the relative errors between the simulated and measured stacking angles and maximum shear were 3.19% and 5.29%, respectively. As a result, the safflower simulation parameters were accurately calibrated, providing a reference for appropriately setting the simulation parameters and designing key mechanical components. [ABSTRACT FROM AUTHOR]

When applied for desulfurization in the coal combustion process, traditional sulfur sorbents have very low sorbent utilization and normally have a negative effect on combustion efficiency. A new type of sulfur sorbent, calcium peroxide (CaO2), synthesized from natural limestone, is proposed and its effects on desulfurization and combustion efficiency are investigated in this paper. The first series of experiments were carried out in a drop tube furnace (DTF). The results showed that CaO2 captured more sulfur than limestone and improved the burnout behavior of coal. To investigate the sulfur removal efficiency of CaO2, the second experiment was carried out in a fixed bed. The results indicated that the sulfur capture capability of CaO2 definitely exceeds that of limestone no matter whether in a low or high temperature range. Moreover, the combustion behavior of coal with and without CaO2 addition was investigated using thermogravity (TG) and differential scanning calorimetric (DSC) analysis. An increase of combustion reactivity and exothermic behavior were determined during the coal combustion process. Furthermore, the possible accelerative mechanism of CaO2 on desulfurization and combustion efficiency is proposed based on further experimental evidence. [ABSTRACT FROM AUTHOR]