Bio: T Elson is an academic researcher from University College London. The author has contributed to research in topics: Fluidization & Drag. The author has an hindex of 9, co-authored 22 publications receiving 2316 citations.
01 Jan 2007
TL;DR: In this paper, high viscous, non-Newtonian Xanthan gum solutions and two transparent model fluids with similar Theological properties were studied under aerated and unaerated conditions in a 0.29m diameter agitated vessel.
Abstract: Highly viscous, non-Newtonian Xanthan gum solutions and two transparent model fluids with similar Theological properties have been studied under aerated (up to 1 vvm) and unaerated conditions in a 0.29m diameter agitated vessel. Rushton disc turbines of size 1/3 and 1/2 of the tank diameter have been used alone and also in conjunction with 6-bladed, 45°-pitch axial flow turbines of the same size at speeds up lo 24 rev/s, enabling specific power inputs of up to 15 W/kg to be imparted. Flow patterns were studied by flow visualisation and hot film anemometry. When the fluids have a yield stress, the fluid divides into a turbulent well-mixed cavern which increases in size with increasing speed with the remainder stagnant. A model for the size of the cavern fits the experimental data well for both aerated and unaerated mixing. Large diameter combinations produce good mixing at about 1 to 2 W/kg which is about 1/3 to 1/4 of that required with small diameter combinations. Single disc turbine impellers a...
TL;DR: In this paper, the use of an X-ray-heavy metal tracer method for the study of mixing patterns in opaque fluids in agitated vessels is described, and a short motion picture of the caverns and flow patterns has been made.
TL;DR: In this article, gas hold-up and liquid circulation rates in a draft-tube bubble column (0.22 m diameter, 85 l capacity) fitted with various diameter draft-tubes are measured for water and aqueous solutions of ethanol, glycerol and carboxymethylcellulose (CMC), respectively.
TL;DR: In this article, the effect of impeller geometry has been studied with a disk turbine (DT), a two-bladed paddle (2BP), a pitched blade turbine (PBT), and a marine propeller (MP).
Abstract: The growth of caverns, formed around rotating impellers in a yield stress fluid during mixing in a stirred vessel, has been studied by observing impeller speeds at which fluid motion was first observed at the vessel's wall and base, and at the free liquid surface. The effect of impeller geometry has been studied with a disk turbine (DT), a two bladed paddle (2BP), a pitched blade turbine (PBT) and a marine propeller (MP). The presence of four baffles (10%) was found to increase the impeller speed at which the cavern reaches the vessel wall by 9% on average over that observed without baffles. After the cavern has reached the vessel walls, impeller type had a small effect upon the vertical expansion of the cavern with increasing impeller speed. Radial flow impellers (DT and 2BP), on average, performed better than an axial flow impeller (MP), with a mixed flow impeller (PBT) in between. Baffles significantly reduce the rate of this vertical expansion of the cavern. Clearance of the impeller from the vessel b...
TL;DR: In this paper, the authors give an account of the development of the idea of yield stress for solids, soft solids and structured liquids from the beginning of this century to the present time.
Abstract: An account is given of the development of the idea of a yield stress for solids, soft solids and structured liquids from the beginning of this century to the present time. Originally, it was accepted that the yield stress of a solid was essentially the point at which, when the applied stress was increased, the deforming solid first began to show liquid-like behaviour, i.e. continual deformation. In the same way, the yield stress of a structured liquid was originally seen as the point at which, when decreasing the applied stress, solid-like behaviour was first noticed, i.e. no continual deformation. However as time went on, and experimental capabilities increased, it became clear, first for solids and lately for soft solids and structured liquids, that although there is usually a small range of stress over which the mechanical properties change dramatically (an apparent yield stress), these materials nevertheless show slow but continual steady deformation when stressed for a long time below this level, having shown an initial linear elastic response to the applied stress. At the lowest stresses, this creep behaviour for solids, soft solids and structured liquids can be described by a Newtonian-plateau viscosity. As the stress is increased the flow behaviour usually changes into a power-law dependence of steady-state shear rate on shear stress. For structured liquids and soft solids, this behaviour generally gives way to Newtonian behaviour at the highest stresses. For structured liquids this transition from very high (creep) viscosity (>106 Pa.s) to mobile liquid (
TL;DR: In this paper, Li-ion battery thermal management systems (BTMSs) including the air, liquid, boiling, heat pipe and solid-liquid phase change based strategies are discussed.
TL;DR: In this paper, the microstructure and mechanical properties of EBM-built Ti-6Al-4V have been systematically investigated in the presence of columnar prior β grains delineated by wavy grain boundary α and transformed α/β structures.
TL;DR: In this article, the authors review the recent technologies of thermal energy storage (TES) using phase change materials (PCM) for various applications, particularly concentrated solar thermal power (CSP) generation systems.
TL;DR: The first successful use of irreversible electroporation for the minimally invasive treatment of aggressive cutaneous tumors implanted in mice was reported, and induced complete regression in 12 out of 13 treated tumors, in the absence of tissue heating.
Abstract: We report the first successful use of irreversible electroporation for the minimally invasive treatment of aggressive cutaneous tumors implanted in mice. Irreversible electroporation is a newly developed non-thermal tissue ablation technique in which certain short duration electrical fields are used to permanently permeabilize the cell membrane, presumably through the formation of nanoscale defects in the cell membrane. Mathematical models of the electrical and thermal fields that develop during the application of the pulses were used to design an efficient treatment protocol with minimal heating of the tissue. Tumor regression was confirmed by histological studies which also revealed that it occurred as a direct result of irreversible cell membrane permeabilization. Parametric studies show that the successful outcome of the procedure is related to the applied electric field strength, the total pulse duration as well as the temporal mode of delivery of the pulses. Our best results were obtained using plate electrodes to deliver across the tumor 80 pulses of 100 µs at 0.3 Hz with an electrical field magnitude of 2500 V/cm. These conditions induced complete regression in 12 out of 13 treated tumors, (92%), in the absence of tissue heating. Irreversible electroporation is thus a new effective modality for non-thermal tumor ablation.