Effects of multi-sequence combination forces on creep characteristics of bales during wheat harvesting

During the baling operation,the wheat stalks are subjected to various mechanisms in the baler and the main form is compression.After the wheat stem is forced by a combination of the threshing cylinder,it needs to be formed under the action of straw baler and meet transport requirements.This paper mainly studies the properties of wheat stalks when baling,and proposes the application of the creep after-effect theory during the baling process.The tension-compression tester was used to perform a 50 mm stalk mechanical test,50 mm stalk static pressure test,35 mm×40 mm×50 mm stalk module static pressure test and bale static pressure test.The measured elastic modulus of the stem sample was 7.59 MPa,and the elastic modulus of the inner core of the stem was 8.24 MPa.The return curve of the single stalk and the bale is consistent with the initial creep and steady-state creep in the creep after-effect theory.A logarithmic function was used for fitting of the first stage with coefficient of determination R2=0.8364,and a linear function was used for fitting of the second stage with coefficient of determination R2=0.9921.The high water content static pressure test suggests that the load in the loading direction is the coupled load of the working load of the hydraulic cylinder and the internal stress of the bale.When harvesting wheat stalks with high moisture content,the density parameter of the bale can be appropriately increased while the load parameter of the hydraulic cylinder can be considered unchanged or even reduced.The adjustment of density and load can still ensure the forming quality of the bale.

Agglomeration Characteristics of River Sand and Wheat Stalk Ash Mixture at High Temperatures

The agglomeration characteristics of river sand and wheat stalk ash mixture at various temperatures are investi- gated using a muffle furnace. The surface structural changes, as well as the elemental makeup of the surface and cross-section of the agglomerates, are analyzed by polarized light microscopy, scanning electron microscopy （SEM）, and energy dispersive X-ray （EDX）. Multi-phase equilibrium calculation is performed with FactSage in identifying the melting behavior of the river sand-wheat stalk ash mixture at high temperatures. No indication of agglomeration is detected below 850~C. At a temperature of 900-1000~C, however, obvious agglomeration is observed and the agglomerates solidify further as temperature increases. The presence of potassium and calcium enrichment causes the formation of a sticky sand surface that induces agglomeration. The main component of the agglomerate surface is KEO-42aO-SiO2, which melts at low temperatures. The formation of molten silicates causes particle cohesion. The main ingredient of the binding phase in the cross-section is K20-SiO2-Na20- Al2Oa--CaO; the agglomeration is not the result of the melting behavior of wheat stalk ash itself but the compre- hensive results of chemical reaction and the melting behavior at high temperatures. The multi-phase equilibrium calculations agree well with the experimental results.