Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 10 of 10
Full-Text Articles in Entire DC Network
Electrochemical Properties Of Passive Films On 440c Stainless Steel, Timothy Lawrence Walzak
Electrochemical Properties Of Passive Films On 440c Stainless Steel, Timothy Lawrence Walzak
Digitized Theses
The properties of passive films formed on 440C stainless steel were investigated using advanced electrochemical techniques for the purpose of establishing a method to measure film stability directly in passivation baths. Electrochemical measurements were sensitive to the passive film properties and were able to quantify the effect of cooling rate on passive film stability. The various techniques used--linear polarization, AC impedance, small amplitude cyclic voltammetry (SACV), and coulostatic transient measurements--provided results that exhibited excellent agreement with the AC impedance technique providing the most information about the interfacial reactions. Full electrochemical characterization of the passive film stability required an evaluation of …
The Study Of The Hydrodynamic Characteristics Of Vertical Upflow Gas-Solids Suspension In The Dilute And Dense Phase Regimes, Steven Lai-Kwok Mok
The Study Of The Hydrodynamic Characteristics Of Vertical Upflow Gas-Solids Suspension In The Dilute And Dense Phase Regimes, Steven Lai-Kwok Mok
Digitized Theses
The present experimental work deals with the study of the hydrodynamic characteristics exhibited by a concurrent upflow gas-solids suspension under fully developed flow conditions in the dilute and the dense phase flow regimes. Pressure drop and the mean solids volumetric concentration were measured in vertical transport line of 20 mm inside diameter using sand particles with an average particle diameter of 210 {dollar}\mu{dollar}m. Mean solids concentration of more than 7 percent and solids loading ratios as high as 75 were obtained in the experiments. The mean solids concentration was measured by trapping the particles in a 4.32 m long test …
Visual Motion Analysis For Robotic Tracking Tasks, Roy Arthur Eagleson
Visual Motion Analysis For Robotic Tracking Tasks, Roy Arthur Eagleson
Digitized Theses
In the field of computational vision, 'motion understanding' roughly describes a system's ability to extract information about the 3D position, trajectory, or structure of visible objects by analysing the way their 2D images change over time. Although this inverse problem is ill-posed at outset, it is possible to utilize the principle of spatio-temporal coherence the hypothesis that objects surfaces and motion are locally continuous--to form localized estimates of the changing state of regions of the image. Two main results are achieved in the thesis:;A technique is presented for estimating the infinitesimal translation group component acting at a local spatial neighbourhood …
Boundary Condition Methods In The Numerical Solution Of The Navier-Stokes Equations With The Application To Free Surface Problems, Hua Yang
Digitized Theses
This thesis is divided into two main parts. Each is related to the numerical simulation of fluid flows. The first part is concerned with the treatment of pressure or vorticity boundary conditions in the numerical solution of the Navier-Stokes equations; and the second part is concerned with the numerical algorithm for simulating the dynamics of capillary surface.;In Part I, two new accurate finite-difference algorithms are described. They can be easily adapted on a uniform grid for solving general flows. The first approach, designated as Zero Perturbation Method, uses the combination of the momentum and divergence equations at the boundary to …
Behaviour Of Heavily Reinforced Embankments On Soft Foundations, Brian Lucien Mylleville
Behaviour Of Heavily Reinforced Embankments On Soft Foundations, Brian Lucien Mylleville
Digitized Theses
The behaviour of both geosynthetic and steel strip reinforced embankments constructed on soft foundations is investigated using the finite element method.;The results of finite element analysis are shown to be in good agreement with the observed performance of a full-scale geogrid reinforced embankment constructed on a very soft deposit of peat and organic silt. Stage I construction was back-analyzed using information obtained from the program of field monitoring together with engineering properties of the soils obtained from laboratory tests.;Finite element analyses are used to study the effects of reinforcement such as high modulus geosynthetics and steel strips, on the undrained …
Kinematic Waves And Governing Equations In Bubble Columns And Three-Phase Fluidized Beds, Lopez Alberto Soria
Kinematic Waves And Governing Equations In Bubble Columns And Three-Phase Fluidized Beds, Lopez Alberto Soria
Digitized Theses
New averaged topological equations (ATEs) were obtained from a geometric description of a dispersed two-phase flow using the derivatives of a multi-step and a multi-delta distribution functions as well as a local volume averaging technique. Similar distribution functions were also defined and combined for the obtention of averaged transport equations for multiphase systems considering relevant interfacial effects. A consistency test performed on the set of averaged transport equations shows that the approach followed renders a self-consistent set of governing equations for a multiphase system with an arbitrary number of phases and relevant interfacial effects. Combination of the ATEs and the …
Enhancement Of Gas-Liquid And Particle-Liquid Mass Transfer In Bubble Columns And Three-Phase Fluidized Beds, Anand Prakash
Enhancement Of Gas-Liquid And Particle-Liquid Mass Transfer In Bubble Columns And Three-Phase Fluidized Beds, Anand Prakash
Digitized Theses
Mass transfer is an important consideration in the design of multiphase contactors. While gas-liquid mass transfer is important for two-phase contactors, both gas-liquid and liquid-solid mass transfer need to be considered for the design three-phase contactors. Many industrial processes such as coal liquefaction, petrochemical, waste water treatment or fermentation processes involve gas absorption in a liquid with or without the presence of inert or catalyst solid particles. When mass transfer is the rate limiting step, the overall rate can be improved by enhancing the rate of mass transfer. This study investigated gas-liquid and liquid-solid mass transfer in bubble columns and …
Modelling Catalytic Cracking In A Novel Riser Simulator (Volumes I And Ii), Daniel William Kraemer
Modelling Catalytic Cracking In A Novel Riser Simulator (Volumes I And Ii), Daniel William Kraemer
Digitized Theses
A 45 mL bench-scale internal recycle reactor, named a 'Riser Simulator' was used to study the kinetics of catalytic cracking. This reaction system is well suited for riser cracking reactions since it can be operated at reaction times as low as 3 seconds and can simulate the reaction regime of a riser. The reactor operates in a batch mode with a gas recirculation in the upward direction through the central catalyst zone to maintain a well fluidized bed.;Experimental runs performed in the unit included the cracking of two commercial feedstocks and three mixtures of pure light oil compounds with two …
Pseudoadiabatic Catalytic Reactor For The Direct Conversion Of Synthesis Gas Into Hydrocarbons, Francois Simard
Pseudoadiabatic Catalytic Reactor For The Direct Conversion Of Synthesis Gas Into Hydrocarbons, Francois Simard
Digitized Theses
This dissertation describes the study of the Pseudoadiabatic fixed-bed catalytic reactor for the one-step conversion of synthesis gas into gasoline using a bifunctional catalyst. The bifunctional catalyst allows to combine the thee steps of methanol synthesis, methanol dehydration and methanol conversion to gasoline, occurring in the adiabatic configuration of the Mobil MTG process, in one single reactor. Moreover, the use of the Pseudoadiabatic reactor offers good control of the temperature distribution, thermal symmetry and reduced parametric sensitivity for this very exothermic reaction.;The catalyst used in the context of this research was a bifunctional catalyst composed of a mixture of a …
A Numerical And Interferometric Study Of Natural Convective Heat Transfer From Divided And Undivided Vertical Channels, David Naylor
A Numerical And Interferometric Study Of Natural Convective Heat Transfer From Divided And Undivided Vertical Channels, David Naylor
Digitized Theses
A numerical and experimental study has been conducted on two-dimensional laminar natural convection heat transfer in an undivided and divided vertical isothermal channel. For the divided channel configuration, an isothermal plate at the same temperature as the channel walls was located on the channel centre line. The study examined the effect of Rayleigh number, plate-to-channel length ratio, vertical plate position, and plate thickness on the heat transfer from the channel walls, the dividing plate and the channel as a whole.;Solutions to both the full elliptic and parabolic forms of the Navier-Stokes and energy equations have been obtained for Prandtl number …