Analysis of pressure and heat distribution in a dilating or contracting filter chamber with two outlets using multivariate spectral quasilinearization method

The development of efficient filters is an essential part of industrial machinery design, specifically to increase the lifespan of a machine. In the filter chamber design considered in this study, the magnetic material is placed along the horizontal surface of the filter chamber. The inside of the filter chamber is layered with a porous material to restrict the outflow of unwanted particles. This study aims to investigate the flow, pressure, and heat distribution in a dilating or contracting filter chamber with two outlets driven by injection through a permeable surface. The proposed model of the fluid dynamics within the filter chamber follows the conservation equations in the form of partial differential equations. The model equations are further reduced to a steady case through Lie's symmetry group of transformation. They are then solved using a multivariate spectral-based quasilinearization method on the Chebyshev–Gauss–Lobatto nodes. Insights and analyses of the thermophysical parameters that drive optimal outflow during the filtration process are provided through the graphs of the numerical solutions of the differential equations. We find, among other results, that expansion of the filter chamber leads to an overall decrease in internal pressure and an increase in heat distribution inside the filter chamber. The results also show that shrinking the filter chamber increases the internal momentum inside the filter, which leads to more outflow of filtrates.     

Preparation of α-cordierite through mechanochemical activation of MgO–Al2O3–SiO2 ternary system

Samples of the ternary system MgO–Al₂O₃–SiO₂ with stoichiometric composition in relation to α-cordierite (Mg₂A_l4Si₅O₁₈), consisting of 22.2 mol% MgO, 22.2 mol% Al₂O₃, and 55.6 mol% SiO₂, were activated in a low energy mill with a constant speed of 100 rpm, in an aqueous medium. The precursors used were corundum (Al₂O₃), silica gel HF254 type 60 (SiO₂), and periclase (MgO). The objective of the present study was to evaluate the effect of mechanochemical activation on the solid-state synthesis of α-cordierite, using a low energy ball mill. Another objective was to shed light on the effect of mechanochemical activation on the steps of α-cordierite formation. For this end several grinding conditions were evaluated, varying the time and mass ratio of precursors/grinding elements, as well as calcination at different temperatures between 950 °C and 1350 °C for 2 h. The samples were analyzed for the determination of the formed phases by Infrared (IR) and X-ray Diffraction (XRD). The phases identified in uncalcined samples were brucite (Mg(OH)₂), forsterite (Mg₂SiO₄), enstatite (MgSiO₃), spinel (MgAl₂O₃), amorphous silica (SiO₂), corundum (α-Al₂O₃), and zirconia (monoclinic and tetragonal ZrO₂). The lowest temperature corresponding to the formation of α-cordierite (α-Mg₂Al₄Si₅O₁₈) was 1150 °C and a considerable amount of this phase (16.2%) was observed at this temperature, for the sample with the higher mechanochemical activation. In a solid-state reaction, α-cordierite is normally obtained at around 1400 °C, therefore, the formation of this phase at 1150 °C confirms that the mechanochemical activation method, using a low-cost ball mill, is efficient in reducing the solid-state reaction temperature.     

Analytical approach on magnetohydrodynamic Casson fluid flow past a stretching sheet via Adomian decomposition method

Flow phenomena of three-dimensional conducting Casson fluid through a stretching sheet are proposed in the present investigation with the impact of the magnetic parameter in a permeable medium. The adaptation of particular transformations is useful to modify the governing equations into their nondimensional as well as the ordinary form. However, these transformed equations are nonlinear and approximate analytical methods for the solution of the complex form of governing equations. In particular, the Adomian decomposition method is proposed for the solution. The behavior of several variables, such as the magnetic and porous matrix, on the flow profile as well as the rate of shear stress, are discussed via graphs and tables. The conformity of the current result with the earlier study shows a road map for further investigation. The major concluding remarks are; the retardation in the velocity distribution is rendered due to an increase in the Casson parameter moreover, the Casson parameter favors in reducing the rate of shear stress coefficient in magnitude.     

饱和块状混合回填土地基的一维固结分析

用块状渣土置换软弱地基和回填低洼谷地等是处置工程渣土的有效途径。为了分析饱和块状混合回填土地基的固结性状，运用混合物理论建立了其一维固结模型。首先，假定块状土固相和充填土固相之间满足等应变条件，获得了饱和块状混合回填土中各相应变与块状土孔隙变形和充填土孔隙变形的关系式。其次，在小应变条件下，根据自由能势函数方程建立了饱和块状混合回填土的一维线弹性本构方程，再结合达西定律和应力平衡方程获得了一维固结控制方程。再次，利用分离变量法得到一维固结解析解，通过退化本文模型与已有模型进行对比，验证了本文模型的正确性。最后，基于所得解析解，分析了充填土孔隙渗透系数、块状土孔隙渗透系数以及流体交换参数等因素对饱和块状混合回填土地基固结性状的影响。分析结果表明：充填土孔隙渗透系数对饱和块状混合回填土地基整体固结性状起主导作用；在固结初期，块状土超孔压会有一定程度的上升，且3个参数具有相似的作用机理。     

磨料有序排布电镀砂轮的制备及其把持力研究

为解决电镀砂轮磨削加工中容屑空间不足的问题，采用点胶微粘接的方法制备了磨料有序排布的电镀砂轮，分析了磨料粘接效果和镀层力学性能。通过SEM分析了磨料/镀层/导电胶的结合界面，并进行了干磨削试验。研究结果表明，直径约为磨料粒径40%的胶点可粘接住磨料，单个胶点上粘接多颗磨料的占比小于6%；双脉冲电镀工艺制备的镀层显微硬度大于500HV，表层残余应力小于100MPa，磨料/镀层/导电胶之间的界面贴合紧密，无明显缺陷；砂轮在磨削时没有出现磨料脱落现象。     

高压气淬设备与工艺

简要介绍了气体淬火介质及ECM气体淬火设备的特性,同时介绍了ECM气体分级淬火工艺的原理,并结合实际生产案例,论述了分级气淬工艺较普通气淬工艺的优越性。     

木片筛余物高得率半化学法清洁制浆技术研究

以太阳纸业备料车间木片筛选碎料（筛余物）为原料，对其烧碱法半化学制浆的实验室工艺和生产试验进行了研究。结果表明，筛余物采用半化学法制浆可获得较高得率和环压强度的纸浆，且用碱量对纸浆性能有显著影响。相对8%NaOH （相对于绝干原料）化学预处理，采用14%NaOH化学预处理结合两段浆浓22%的高浓磨浆工艺，所制半化学浆抄造浆张的裂断长和环压指数分别达2.89 km和9.76 N·m/g，是前者的1.9倍和1.2倍，而且优于现用国内OCC废纸浆抄造浆张；生产试验得到的浆张性能指标与实验室相吻合，其中紧度和环压强度分别达到GB/T 13023—2008瓦楞芯（原）纸AA级和A级优等品要求。     

Investigation of the influence of iron-containing abrasives on the corrosion behaviour of the aluminium alloy AlSi1.2Mg0.4

The corrosion resistance of aluminium surfaces is closely linked to the surface state after a grinding process. For years, iron-containing abrasive materials were suspected to lead to increased corrosion susceptibility after processing of aluminium surfaces. To prove a possible correlation between the iron content of an abrasive and the corrosion behaviour of aluminium components, scientific investigations and experimentally practical corrosion tests are necessary. For the current investigation, specimens of a technical Al-Si alloy from the same batch were used. The test specimens were mechanically ground with various resin-bonded model abrasives containing different iron contents. The performed corrosion tests did not reveal a negative influence of the different iron-containing abrasives on the corrosion behaviour of the Al–Si alloy. However, the most sensitive measuring method (electrochemical noise) showed differences in the surface activity depending on the type of abrasive.     

基于气动性能与刚度特性的风力机翼型优化设计

结合翼型泛函集成理论与叶片截面刚度矩阵数学计算模型,提出了风力机中等厚度翼型气动性能与结构刚度特性的一体化设计方法,实现了翼型气动性能与叶片截面刚度特性的同时提高。对考虑叶片截面铺层参数变化设计的WQ-B300翼型与DU97-W-300翼型进行了气动性能与结构刚度特性对比分析,结果表明:相比于DU97-W-300翼型,WQ-B300翼型的气动性能与叶片截面刚度性能均有显著提高,其挥舞刚度和摆振刚度分别提高了6.2%和8.4%,验证了该设计方法的可行性,给风力机中等厚度及大厚度翼型设计提供了一种思路。