The Effect of the Thickness of Fe2 Al5 Phase Layer at Fe/Al Interface on the Mechanics Behavior of Hot Dip Aluminizing Coating

Hot Dip Aluminized Coatings with different thickness were prepared on Q235 steel in aluminum solutions with different temperature for certain time. Through tensile tests and in-situ SEM observations, the effect of the coating's microstructure on the tensile strength of the samples was studied. It was disclosed at certain aluminum solution temperature,transaction layers mainly composed of Fe2 Al5 phase got thicker with time prolonging, and this changed initial crack's extending direction from parallel with to vertical with stretching direction. The change in crack direction decreased tensile strength of samples, thus made the coating easy to break. It was concluded that the existence of thick Fe2 Al5 phase layer was the basic reason for the lowering of tensile strength of the coating.     

On the SPH tensile instability in forming viscous liquid drops

Smoothed Particle Hydrodynamics (SPH) simulations of elastic solids and viscous fluids may suffer from unphysical clustering of particles due to the tensile instability. Recent work has shown that in simulations of elastic or brittle solids the instability can be removed by an artificial stress whose form is derived from a linear perturbation analysis of the full set of governing SPH equations. While a linear analysis cannot be used to derive the corresponding form of the artificial stress for a viscous fluid, here we show that the same construction which applies to elastic solids may also work for viscous fluids provided that the constant parameter ? entering in the definition of the artificial stress is properly chosen. As a suitable test case, we model the formation of a circular van der Waals liquid drop and show that the tensile instability is removed when an artificial viscous force and energy generation term are added to the standard SPH equations of motion and energy, respectively. The optimal value of the constant ? is constrained by the ability of the model simulation to reproduce both a sufficiently smoothed density profile and the van der Waals phase diagram.     

水溶性抗磨剂在水基切削液中的应用性试验研究

本文采用攻丝扭矩试验法，研究了两种具有优良的抗磨减摩等性能的水溶性抗磨剂（即长碳链烷基酚聚氧乙烯醚磷（硫）酸锌盐和脂肪酸钾盐）在切削液方面的应用性能。研究表明，WBC－1（含长碳链烷基酚聚氧乙烯醚磷酸锌盐）和WBC－2（含脂肪酸钾盐）水基切削液的切削性能略优于国内同类水基极压乳化液，稍逊于菜油切削油，但它的成本和清洗性大大优于菜油，具有较大的实用价值。     

Adsorption of Uranium from Dilute Aqueous Solution on Inorganic Adsorbents

Abstract

The adsorption of uranium from a dilute aqueous solution by a large number of inorganic adsorbents has been investigated. A mixture of aluminum hydroxide, ferric hydroxide, and activated carbon in the weight ratio 1:3:4 has shown a high adsorbability for uranium. The separation of uranium from a dilute aqueous solution by this mixed adsorbent under various temperatures and pH values has been studied. The adsorbability was found to exhibit a maximum at pH 4.0 to 5.5 and to decrease with increasing temperature. A number of eluting solutions for the desorption of uranium from the mixed adsorbent were also tested; 1 N (NH₄)₂ CO ₃ was found to be the most suitable eluting solution (93% recovery of uranium).     

Auslegung von Blasensäulen mithilfe von Compartmentmodellen

In bubble columns, the phenomena of mass and heat transfer as well as the reaction are closely linked to the complex fluid dynamics. Compartment modeling offers the opportunity to integrate these phenomena while enabling an axial and radial distribution with acceptable computing effort. This article includes methods for generating the compartment geometry and fluid dynamic parameters of this modeling approach, facilitating the opportunity to optimize an industrial bubble column.     

Agglomeration Mechanism of Nanoparticles by Adding Coarse Fluid Catalytic Cracking Particles

The agglomeration mechanism of SiO₂, TiO₂, and ZnO nanoparticles by adding coarse fluid catalytic cracking (FCC) particles is studied. The core‐shell structure of agglomerates is revealed on the basis of experimental analyses. Nanoparticles can be fluidized by forming agglomerates of the core‐shell structure with coarse FCC particles. The porosity of core‐shell structure agglomerates and the average roundness value were found to be distinctly lower than those of pure nanoparticle agglomerates. In addition, the cohesion of the core‐shell structure agglomerates is far less than that of the agglomerates formed by pure nanoparticles. Due to the smaller porosity, irregular shape, and relatively low cohesion, the fluidization behavior of core‐shell structure agglomerates is better than that of pure nanoparticle agglomerates.     

A three dimensional exact equation for the turbulent dissipation rate of Generalised Newtonian Fluids

The flow of non-Newtonian fluids is of interest in many biological and industrial applications, including nanofluids. Most of the papers of the literature on turbulent non-Newtonian fluids focused the attention on viscoelastic fluids. In order to make accurate and low cost prediction of turbulent inelastic non-Newtonian fluids, a RANS Generalised Newtonian Fluid (GNF) turbulence model, based on the exact equations for the turbulent variables, is required. In a previous paper of the same authors the exact equations for the turbulent kinetic energy and the dissipation rate have been derived in a two-dimensional (2D) domain, through the introduction of an apparent viscosity equation. The aim of the present paper is to extend the approach to a three-dimensional (3D) domain, giving the full mathematical demonstration of the exact equations.     

分析无机絮凝剂混凝机理中的力化学因素

以混凝机理为基础,建立了无机絮凝剂的混凝物理模型。通过混凝物理模型与无机絮凝剂的双电层压缩机理相结合,研究无机絮凝剂和投加时的稀释比例不同产生的效果,指出无机絮凝剂的混凝机理中存在流体力化学效应。