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Associate Professor Mark Nelson

2012

Analysis

Articles 1 - 6 of 6

Full-Text Articles in Physical Sciences and Mathematics

A Fundamental Analysis Of Continuous Flow Bioreactor And Membrane Reactor Models With Non-Competitive Product Inhibition. Ii. Exponential Inhibition, Mark Nelson, Wei Xian Lim Dec 2012

A Fundamental Analysis Of Continuous Flow Bioreactor And Membrane Reactor Models With Non-Competitive Product Inhibition. Ii. Exponential Inhibition, Mark Nelson, Wei Xian Lim

Associate Professor Mark Nelson

The steady-state production of a product produced through the growth of microorganisms in a continuous flow bioreactor is presented. A generalised reactor model is used in which both the classic well-stirred bioreactor and the idealised membrane bioreactor are considered as special cases. The reaction is assumed to be governed by Monod growth kinetics subject to non-competitive product inhibition. Inhibition is modelled as a decaying exponential function of the product concentration. This reaction scheme is well documented in the literature, although a stability analysis of the governing equations has not previously been presented. The performance of a well-stirred bioreactor with microorganisms …


Analysis Of A Chemostat Model With Variable Yield Coefficient: Contois Kinetics., Rubayyi Alqahtani, Mark Nelson, Annette Worthy Dec 2012

Analysis Of A Chemostat Model With Variable Yield Coefficient: Contois Kinetics., Rubayyi Alqahtani, Mark Nelson, Annette Worthy

Associate Professor Mark Nelson

Food processing wastewaters and slurries typically contain high concentrations of biodegradable organic matter. Before the wastewater can be discharged, the pollutant concentration must be reduced. One way to achieve this is by using a biological species (biomass) that consumes the organic matter (substrate). We investigate an unstructured kinetic model for a bioreactor with a variable yield coefficient, taking into account the death rate of the microorganisms. The growth rate is given by a Contois expression, which is often used to model the growth of biomass in wastewaters containing biodegradable organic materials. The analysis shows that the system has natural oscillations …


A Fundamental Analysis Of Continuous Flow Bioreactor Models And Membrane Reactor Models To Process Industrial Wastewaters, Mark Nelson, Xiao Dong Chen, Easwaran Balakrishnan, Harvinder Sidhu Dec 2012

A Fundamental Analysis Of Continuous Flow Bioreactor Models And Membrane Reactor Models To Process Industrial Wastewaters, Mark Nelson, Xiao Dong Chen, Easwaran Balakrishnan, Harvinder Sidhu

Associate Professor Mark Nelson

No abstract provided.


A Fundamental Analysis Of Continuous Flow Bioreactor Models With Recycle Around Each Reactor Governed By Contois Kinetics. Iii. Two And Three Reactor Cascades, Rubayyi Alqahtani, Mark Nelson, Annette Worthy Dec 2012

A Fundamental Analysis Of Continuous Flow Bioreactor Models With Recycle Around Each Reactor Governed By Contois Kinetics. Iii. Two And Three Reactor Cascades, Rubayyi Alqahtani, Mark Nelson, Annette Worthy

Associate Professor Mark Nelson

The steady-state treatment of industrial wastewaters in a cascade reactor with recycle is analyzed. A number of cascades with alternative arrangements of the settling units are considered. Specifically, we consider the case when the recycle stream leaving a settling unit which is placed around a reactor goes back into the feed stream for that reactor. The Contois kinetic model is used to study the degradation of biodegradable organic materials. The steady-states for the model are found and their stability determined as a function of the total residence time in the cascade. Asymptotic solutions in the limit of large total residence …


A Mathematical Model For The Biological Treatment Of Industrial Wastewater In A Reactor Cascade, Rubayyi Turki Alqahtani, Mark Nelson, Annette Worthy Dec 2012

A Mathematical Model For The Biological Treatment Of Industrial Wastewater In A Reactor Cascade, Rubayyi Turki Alqahtani, Mark Nelson, Annette Worthy

Associate Professor Mark Nelson

Many industrial processes, particularly in the food industry, produce slurries or wastewaters containing high concentrations of biodegradable organic materials. Before these contaminated wastewaters can be discharged the concentration of the biodegradable organic pollutant must be reduced. One way to do this is to pass the wastewater through a bioreactor containing biomass which grows through consumption of the pollutant. Anaerobic conditions are often favoured for the processing of waste materials with high levels of biodegradable organic pollutants as these can be removed with low investment and operational costs. We investigate the steady state effluent concentration leaving a cascade of two reactors. …


Mathematical Analysis Of Self-Heating In Compost Piles, Harvinder Sidhu, Mark Nelson, Nadeem Ansari, Xiao Dong Chen Dec 2012

Mathematical Analysis Of Self-Heating In Compost Piles, Harvinder Sidhu, Mark Nelson, Nadeem Ansari, Xiao Dong Chen

Associate Professor Mark Nelson

We model the increase in temperature in compost piles or landfill sites due to micro-organisms undergoing exothermic reactions. The model incorporates the heat release due to biological activity within the pile and the heat release due to the oxidation of cellulosic materials. The heat release rate due to biological activity is modelled by a function which is a monotonic increasing function of temperature over a particular range and followed by a monotone decreasing function of temperature. This functionality represents the fact that micro-organisms die or become dormant at high temperatures. The heat release due to the oxidation reaction is modelled …