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。     

Modeling subway air flow using CFD

A more realistic Computational Fluid Dynamics approach has been developed to model air flow in subway tunnels and stations. This modeling incorporates the effects of multi-car trains as they arrive and depart in a network of interconnected stations at realistic speeds. It also includes thermal sources within the stations and a coupling to the street level through inlets and outlets. This new approach is validated against experimental data, and numerical simulations are carried out in realistic subway station geometries. The air flow dynamics in these stations are quantified in terms of their spatial complexity and temporal stability. The air flow dynamics correlate to the dispersion and transport of pollutants though the stations.     

The research on failure analysis of fluid cylinder and fatigue life prediction

To analyze the reasons of fluid cylinders’ rupture, macro-analysis, SEM, composition inspection, metallographic analysis, hardness test and mechanics performance test of fluid cylinders materials were implemented. Two different kinds of fatigue life prediction methods have been proposed which are based on total life analysis and strain–life methodology. The results indicate that: the failure cylinders’ material quality is satisfactory. Fatigue damage caused by high working, stress and corrosion is the main reason of cracking. The fatigue life prediction illustrates that strain–life methodology is well adapted to fluid cylinders.     

Thermal analysis and design of a volumetric solar absorber depending on the porosity

The thermal evaluation of different absorber configurations for a volumetric solar receiver designed for a solar furnace has been carried out by means of commercial Computational Fluid Dynamics (CFD) software in a 2D numerical model. Simulation results for proposed configurations depending on the porosity are discussed and compared to find the optimum configuration for which flow instabilities and thermal stresses are minimized and higher efficiencies are reached. The results obtained from the comparison of air velocity and thermal profiles at the absorber outlet propose a gradual-porosity configuration as an alternative to a previous design of a porous silicon-carbide honeycomb structure in order to heat an air stream up to temperatures suited for several high-temperature industrial processes.