The agglomeration characteristics of river sand and wheat stalk ash mixture at various temperatures are investigated using a muffle furnace. The surface structural changes, as well as the elemental makeup of the surfa...The agglomeration characteristics of river sand and wheat stalk ash mixture at various temperatures are investigated 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 K_2O-CaO-SiO_2, 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 K_2O-SiO_2-Na_2O-Al_2O_3-CaO; the agglomeration is not the result of the melting behavior of wheat stalk ash itself but the comprehensive results of chemical reaction and the melting behavior at high temperatures. The multi-phase equilibrium calculations agree well with the experimental results.展开更多
该文以小麦茎为研究对象,建立了有限元计算模型。通过非线性屈曲分析,发现通过改变几何或者物理参数能够模拟出小麦茎不同的失稳形式,其中最明显的影响因素为壁厚和横、纵向弹性模量比。以此为参考,对两个生长期的小麦茎进行四点弯曲试...该文以小麦茎为研究对象,建立了有限元计算模型。通过非线性屈曲分析,发现通过改变几何或者物理参数能够模拟出小麦茎不同的失稳形式,其中最明显的影响因素为壁厚和横、纵向弹性模量比。以此为参考,对两个生长期的小麦茎进行四点弯曲试验,研究不同节位茎的抗弯能力,曲率与惯性矩之间的关系和失稳模式。研究表明B raz ier屈曲是小麦茎失稳的主要原因。从开花期到成熟期茎抗弯刚度下降,发生B raz ier屈曲的几率增加。展开更多
基金supported by National Natural Science Foundation of China(Project Code:50706055)
文摘The agglomeration characteristics of river sand and wheat stalk ash mixture at various temperatures are investigated 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 K_2O-CaO-SiO_2, 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 K_2O-SiO_2-Na_2O-Al_2O_3-CaO; the agglomeration is not the result of the melting behavior of wheat stalk ash itself but the comprehensive results of chemical reaction and the melting behavior at high temperatures. The multi-phase equilibrium calculations agree well with the experimental results.
文摘该文以小麦茎为研究对象,建立了有限元计算模型。通过非线性屈曲分析,发现通过改变几何或者物理参数能够模拟出小麦茎不同的失稳形式,其中最明显的影响因素为壁厚和横、纵向弹性模量比。以此为参考,对两个生长期的小麦茎进行四点弯曲试验,研究不同节位茎的抗弯能力,曲率与惯性矩之间的关系和失稳模式。研究表明B raz ier屈曲是小麦茎失稳的主要原因。从开花期到成熟期茎抗弯刚度下降,发生B raz ier屈曲的几率增加。
