Michel Perrier

• B.Ing. (Poly), Ph.D. (McGill) D.Sc.A. hon. (Mons)
• Professor Emeritus at Polytechnique Montréal

A pre-hydrolysate is an aqueous stream obtained during the production of hardwood kraft dissolving pulp. It is rich in sugars and contains dissolved organic matters. The purpose of this study is to investigate the optimization of lignin recovery from wood pre-hydrolysates and to characterize the extracted lignin. The optimal conditions for lignin e...

This work aimed to investigate the effects of biomass species on fermentable sugar production, with respect to both energy consumption and sugar yield, using the modified traditional mechanical system from Pulp & Paper Mills as a potential biorefinery step. The study explored four lignocellulosic biomass species including corn stover, alfalfa, whit...

The support effect on the low temperature catalytic oxidation of methane over palladium catalysts was studied by comparing a series of metal oxides as the support. Samples of 0.010 g/g Pd catalysts supported on different grades and/or phases of TiO2, Al2O3, and ZrO2 were prepared via incipient impregnation and their catalytic activity was evaluated...

This work investigated fermentable sugar production by modifying the traditional classical mechanical system used by Pulp & Paper Mills as a potential biorefinery step regarding energy consumption and sugar yield. The study explored the effectiveness of thermal pretreatment, with and without the addition of NaOH, followed by a disk refining pretrea...

Mammalian-inducible expression systems are increasingly available and offer an attractive platform for the production of recombinant proteins. In this work, we have conducted process development for a cumate-inducible GS-CHO cell-line-expressing rituximab. To cope with the limitations encountered in batch when inducing at high cell densities, we ha...

In order to maximize cell growth and productivity for an inducible CHO cell line expressing rituximab, various fed-batch culture strategies were investigated. In each case, the performance was evaluated for cultures induced at moderate and high cell density conditions (4 × 10 ⁶ and 10 × 10 ⁶ cells/mL) to assess the impact of the timing of induction...

Inducible mammalian expression systems are becoming increasingly available and are not only useful for the production of cytotoxic/cytostatic products, but also confer the unique ability to uncouple the growth and production phases. In this work, we have specifically investigated how the cell culture state at the time of induction influences the cu...

Purpose A dry coating technology has been evaluated as a dry agglomeration technique for a typical pharmaceutical formulation. Its efficiency was compared with that of the more commonly used roller compaction dry granulation. Methods A commercially available system was selected as a representative technology. The selection was based on batch size,...

During dissolving pulp production, the extraction of hemicellulose and other organics from hardwood chips prior to the kraft pulping process can be performed using steam or hot water. The pre-hydrolysate from this step is rich in sugars and contains a considerable amount of lignin. It was estimated that the lignin content in this stream can be as h...

This study describes a new approach for achieving stable long-term performance and maximizing the removal of chemical oxygen demand (COD) in a Microbial Electrolysis Cell (MEC). In the proposed approach, the MEC power supply is periodically disconnected, e.g. at a frequency of 0.1–0.5 Hz and a duty cycle of 90–95%. To evaluate the impact of such pe...

As an alternative to the chemical approach reducing the pH of black liquor to precipitate lignin using carbon dioxide and sulfuric acid, we have developed an electrochemical avenue for lowering pH while recovering caustic. It includes electrolytic treatment of black liquor that reduces its alkalinity to the critical point of lignin precipitation wi...

Efforts in developing microbial electrolysis cells (MECs) resulted in several novel approaches for wastewater treatment and bioelectrosynthesis. Practical implementation of these approaches necessitates the development of an adequate system for real-time (on-line) monitoring and diagnostics of MEC performance. This study describes a simple MEC equi...

During the production of kraft dissolving pulp a pre-hydrolysate stream is generated prior to pulping. This pre-hydrolysate is a potential feedstock for the production of high value-added bioproducts. It contains a considerable amount of dissolved organics such as hemicelluloses, lignin and acetic acid. The purpose of this study was to investigate...

This study demonstrates degradation of synthetic wastewater in two MFCs hydraulically connected in series. To maximize chemical oxygen demand (COD) removal, external resistance of each MFC is optimized using a perturbation-observation maximum power point algorithm. Under optimal operating conditions a removal efficiency over 90% is achieved at an i...

This paper focuses on the production of furfural from a simulated kraft dissolving pulp mill pre-hydrolysate solution that is rich in pentoses. Presently, this stream at the mill is mixed with the black liquor and then burned to recover some of the energy needed for the process. However, this pre-hydrolysate would have a higher potential if used as...

The bio refinery initiative in the pulp and paper industry aims at diversifying their product offering including value added biomaterials from lignin. As an alternative to the chemical method using carbon dioxide and sulfuric acid, we have developed an electrochemical approach to precipitate lignin from black liquor while recovering caustic. Our ap...

During kraft dissolving pulp production, the extraction of hemicellulose and other organics from hardwood chips prior to the pulping process is performed using hot water or steam. The pre-hydrolysate from this step is rich in sugars, lignin and acetic acid. Presently, this stream is added to black liquor and burned to produce energy for the process...

Laboratory-scale microbial fuel cells are often operated with a constant electrical load. Meanwhile, variations in influent strength and quality, as well as the processes of biofilm growth and decay lead to significant changes of the MFC internal resistance over time. This inevitably results in a mismatch between the internal and the external resis...

The main limitation of perturbation based extremum seeking methods is the requirement of a multiple time-scale separation between the system dynamics, the perturbation frequency, and the adaptation rate so as to avoid interactions and possible instabilities. This causes the convergence to be extremely slow. In the present work, we propose a simple...

The perturbation based extremum seeking control is equivalent to fitting a linear model to the data and computing the objective function gradient from this fitted linear model. The present paper asks the question of whether increasing the model complexity e.g., by using a quadratic or a polynomial model of higher order would improve precision. It i...

The main limitation of perturbation based extremum seeking methods is the requirement of a multiple time-scale separation between the system dynamics, the perturbation frequency, and the adaptation rate so as to avoid interactions and possible instabilities. This causes the convergence to be extremely slow. In the present work, we propose a simple...

Q10 Significant figures pollute literature data. Do not carry more than your experiments warrant. Order the list below from most certain to most uncertain (in K).[1] (a) 310 °C (b) 583.15 K (c) 310 °C ΔT = ±1% (d) 583.15 KΔT = ±1%K.

Confronted by a steady decline in the demand for commodity papers, the pulp and paper industry has undertaken intensive R&D efforts to identify and develop new non paper products that could be manufactured from the forest biomass. The components of wood that can be separated and converted into new non paper products are the cellulose, hemicellulose...

What do error bars in graphs or uncertainty in variables ( ) represent? [1] (Multiple answers) Standard deviation, Standard error of the mean, Confidence interval, Instrument resolution Maximum and minimum of a range of measurements The correct expression for sample standard deviation is s ; it is for the standard error of the mean and for the conf...

Several recent studies demonstrated significant charge storage in electrochemical biofilms. Aiming to evaluate the impact of charge storage on microbial fuel cell (MFC) performance, this work presents a combined bioelectrochemical-electrical (CBE) model of an MFC. In addition to charge storage, the CBE model is able to describe fast (ms) and slow (...

Bioelectrochemical systems (BESs) such as Microbial Fuel Cells (MFCs) and Microbial Electrolysis Cells (MECs) are capable of producing energy from renewable organic materials. Over the last decade, extensive experimental work has been dedicated to exploring BES applications for combined energy production and wastewater treatment. These efforts have...

This study describes application of an equivalent circuit model (ECM) for on-line monitoring of microbial fuel cells (MFCs). ECM analytical solutions were derived for MFCs operated with pulse-width modulated electrical load connection at high and low frequencies. These analytical solutions were used to develop an on-line procedure for estimating MF...

Titanium oxy-nitride is synthesized by the in-situ urea-based sol-gel method and is used as an electrocatalyst for the oxygen reduction reaction (ORR). Physicochemical and electrocatalytic properties of the prepared electrocatalysts are compared to those of titanium oxy-nitride electrocatalysts prepared by the other conventional sol-gel methods. He...

In the present article, titanium oxy-nitride (TiON), as a potential electrocatalyst for the oxygen reduction reaction (ORR), is fabricated by four different sol-gel methods. Physicochemical properties (structure, chemical composition, BET surface area, surface morphology, chemical stability, and electrochemical stability) are determined. The ORR in...

This paper presents a state estimator for systems linear in an unknown parameter. The estimate is given via a weighted mean of both an under-and an over-estimate provided by an interval observer. The weighting factor is computed in real-time from the difference between the output measurements and the interval bounds. The convergence of the estimate...

This paper introduces a new method for slope seeking control of the model-independent nonlinear continuous static scalar and unconstrained systems. The proposed controller is the generalization of a global optimization scheme based on multi-unit extremum seeking control that drives the estimated gradient to an arbitrary slope. Herein, a monotonical...

Microbial fuel cells (MFCs) are novel devices capable of producing electricity while cleaning wastewater. Developing dynamic control-oriented models for such systems represents a crucial tool for the future design of software sensors and model-based control strategies. To this end, this work presents a MFC process control-oriented model obtained by...

The electrochemical stability and activity of different compositions of titanium and tantalum oxy-nitride nano-catalysts were investigated for the oxygen reduction reaction (ORR). A new sol-gel method was used to produce a nano-powder mixture of Ti and Ta oxynitride from their alkoxides using urea as a nitrogen source. The precursors prepared by th...

Experimental results of the control of the ammonia concentration during the growth phase of a PHB producing process in a fedbatch reactor are presented. The control design is based on the mass balance dynamical equations and does not require any knowledge of the process kinetics. It results in an adaptive linearizing controller where the specific g...

A modified thermodynamic equilibrium model has been developed to improve the prediction of syngas composition produced by the gasification of woody biomass. A comparison of data produced by an equilibrium model with available experimental data from bubbling biomass fluidised bed gasifiers indicates that the equilibrium model significantly underesti...

The forest biomass is an abundant renewable resource from which biofuels can be derived. In the Kraft process the cellulose is extracted from the wood to form the paper pulp while the other organic components, primarily hemicelluloses and lignin, are burnt to produce steam. It is possible to divert part of the hemicelluloses or lignin to produce fu...

This study describes MFC operation with a pulse-width modulated connection of the external resistor (R-PWM mode) at low and high frequencies. Analysis of the output voltage profiles acquired during R-PWM tests showed the presence of slow and fast dynamic components, which can be described by a simple equivalent circuit model suitable for process co...

An efficient global optimization method based on multi-unit extremum seeking has been proposed recently for noise-free nonlinear continuous static, scalar systems. Herein, a monotonically decreasing offset is introduced between the inputs of two identical units and the estimated gradient by finite difference is controlled to zero by an integrator....

Microalgae are microscopic plants that exist in an aquatic environment. They are involved in the production of high value compounds and also have applications in energy production. In this work, the regulation of biomass concentration in a bioreactor is investigated by using an observer-based backstepping control approach. The process is controlled...

Incorporating a biorefinery unit to an operating Kraft pulping process has significant technological, economic and social advantages over the construction of a grassroot biorefinery. Also, the conversion of a Kraft mill from total pulp making to complete biorefinery can be done in a stepwise fashion and so give a company that envisages such transfo...

Microalgae are microscopic plants existing in aquatic environment. They can be used in the production of high value compounds and they have promising opportunities in energy production, wastewater treatment and fixation of carbon dioxide. In this context, the control of the cultivation requires a special attention in order to obtain high amounts of...

Laboratory-scale microbial fuel cells are often operated with a constant electrical load. Meanwhile, variations in influent strength and quality, as well as the processes of biofilm growth and decay lead to significant changes of the MFC internal resistance over time. This inevitably results in a mismatch between the internal and the external resis...

In this paper, we consider the Kalman (or $\mathcal{H}_{2}$ )-filtering problem for discrete-time affine nonlinear descriptor systems. Two types of filter are discussed, namely, (i) singular; and (ii) normal. Sufficient conditions for the solvability of the problem in terms of discrete-time Hamilton–Jacobi–Bellman equations (DHJBEs) are presented...

In this study, the authors consider the H-infinity-filtering problem for discrete-time affine non-linear descriptor systems. Two types of filters are discussed; namely, (i) singular, (ii) normal and sufficient conditions for the solvability of the problem in terms of disrete-time Hamilton-Jacobi-Isaacs equations (DHJIEs) are presented. The results...

We consider the ℋ ∞ -filtering problem for discrete-time singularly-perturbed (two time-scale) nonlinear systems. Two types of filters, namely, (i) decomposition; and (ii) aggregate, are discussed, and sufficient conditions for the approximate solvability of the problem in terms of Discrete-time Hamilton-Jacobi-Isaacs Equations (DHJIEs) are present...

In this paper, we present an adaptive extremum seeking control scheme for fed-batch bioreactors with Haldane kinetics. The proposed adaptive extremum seeking approach utilizes the structure information of the process kinetics to derive a seeking algorithm that drives the system states to the desired setpoints that maximize the biomass production. I...

The objective of this paper is to present a survey on extremum seeking control methods and their applications to process and reaction systems. Two important classes of extremum seeking control approaches are considered: perturbation-based and model-based methods.

An efficient global optimization method based on multi-unit extremum seeking has been proposed recently for scalar and two-input systems. For scalar systems, the global optimum is obtained by controlling the finite-difference gradient and reducing the offset used for calculating this gradient. With two inputs, the uni-variate method is repeated on...

Neural networks (NNs) were used to predict the onset of filamentous bulking, as described by trends in stirred sludge volume index, in a pulp and paper activated sludge treatment system. Variables related to activated sludge biomass viability, namely specific oxygen uptake rate (SOUR) and adenosine triphosphate (ATP), were used as inputs to the NN....

Overflow metabolism characterizes cell strains that are likely to produce inhibiting metabolites as a result of an excess of substrate feeding and a saturated respiratory capacity. In this study, extremum seeking is used to assess the actual critical substrate level, which is a function of the cell respiratory capacity. The latter is modelled as a...

Linear controllers for dynamic systems have been used in a stochastic context to decrease the variance of certain key variables. An extension is to use nonlinear controllers for shaping the entire probability density function (PDF). Typically, polynomial controllers are preferred due to their flexibility and also because their continuity makes them...

Finding the global optimum of an objective function has been of interest in many disciplines. Recently, a global optimisation technique based on multiunit extremum seeking has been proposed for scalar and two-input systems. The idea of multiunit extremum-seeking is to control the gradient evaluated using finite difference between two identical unit...

Finding the global optimum of a nonlinear function is a challenging task that could involve a large number of functional evaluations. In this paper, an algorithm that uses tools from the domain of extremum-seeking is shown to provide an efficient deterministic method for global optimization. Extremum-seeking schemes typically find the local optimum...

During the growth phase of Alcaligenes eutrophus, it was observed that the concentrations of glucose and ammonium ions are inhibitory at a certain level, which affects the specific growth rate. Moreover, it has been established from previous work that (an) unidentified substance(s) inhibit(s) the growth at biomass concentrations above 10 g∙L−1. A m...

Parkinson's disease (PD) is a pernicious neurodegenerative disease for which no cure exists. Its main cellular hallmark is the formation of Lewy inclusion bodies by alpha-synuclein protein aggregation. Energy metabolism is deregulated by etiopathogenic factors of PD and this can have implications in disease onset and progression. However brain ener...

Multi-unit optimization is a recently proposed extremum-seeking technique where the gradient, estimated by finite difference between two identical units, is controlled to zero. The main assumption of having two identical units is rarely verified in practice and it has been noted that differences in the static characteristics can affect the stabilit...

Model-free unconstrained real-time optimization can be realized by controlling the gradient to zero. In this paper, the multiunit optimization framework is used where the gradient is estimated using finite difference between two identical units operating with an offset. It has been recently shown that the global optimization is achieved by reducing...

Microbial Fuel Cells (MFCs) are capable of producing electricity while cleaning wastewater. This novel technology can replace energy-consuming aerobic treatment even if low effluent concentrations are demanded. The goal of this work is to optimize a MFC-based wastewater treatment process. A MFC mathematical model, which accounts for co-existence of...

In this paper, we present an adaptive extremum seeking control scheme for fed-batch bioreactors with Haldane kinetics. The proposed adaptive extremum seeking approach utilizes the structure information of the process kinetics to derive a seeking algorithm that drives the system states to the desired set-points that maximize the biomass production....

In an effort to develop robust control strategies for the wet-end of papermaking, an experimental program was carried out to model the dynamic behaviour of the filler retention in paper using a Fourdrinier pilot paper machine and a cationic poly(acrylamide)/bentonite retention aid system. A dynamic simulation model of the pilot paper machine was de...

This paper addresses the problem of extremum-seeking (real-time steady state optimization of dynamic systems via control of the gradient) under inequality constraints in continuous time. A gradient projection framework is adopted in this paper, where the main challenge lies in the identification of the set of active constraints. It is first shown t...

Microbial fuel cells (MFCs) are capable of producing electricity while cleaning wastewater. The goal of this work is to optimize an MFC-based wastewater treatment process to maximize the amount of wastewater that is cleaned. An MFC mathematical model is used to compare different operating modes and reactor configurations. The following observations...

Microbial fuel cells (MFCs) constitute a novel power generation technology that converts organic waste to electrical energy using microbially catalyzed electrochemical reactions. Since the power output of MFCs changes considerably with varying operating conditions, the online optimization of electrical load (i.e., external resistance) is extremely...

The preparation of large amount of purified helper-dependent adenoviral vector material is hampered by the lack of development of downstream processes with proven records on separation and recovery efficiencies. In order to facilitate the use of clinical-grade helper-dependent virus material for large-scale in vivo studies, a three-step purificatio...

The Activated Sludge Model No. 1 was chosen as the basis for model development and was modified to take into account the specific characteristics of pulp and paper effluents. The model was incorporated to the GPS-X simulation environment (Hydromantis, Hamilton, Ontario, Canada) to study operating deficiencies and nutrient transformations, particula...

Introduction Adaptive linearizing control of bioprocesses Adaptive extremum-seeking control of bioprocesses Appendix: analysis of the parameter convergence Bibliography

Helper-dependent adenoviral vector has demonstrated a high therapeutic potential; however, the poor efficiency of the actual production process hampers further large-scale clinical evaluation. In this work, we evaluated the adenofection protocol, an efficient polyethylenimine transfection strategy, for HDV production. Optimized conditions of PEI-ad...

Microbial Fuel Cells (MFCs) are capable of producing electricity while cleaning wastewater. This novel technology can replace energy-consuming aerobic treatment even if low effluent concentrations are demanded. The goal of this work is to optimize a MFC-based wastewater treatment process. A MFC mathematical model, which accounts for co-existence of...

Model-free unconstrained real-time optimization can be realized by controlling the gradient to zero. In this paper, the multiunit optimization framework is used where the gradient is estimated using finite difference between two identical units operating with an offset. It has been recently shown that the global optimization is achieved by reducing...

Multi-unit optimization is a recently proposed extremum-seeking technique where the gradient, estimated by finite difference between two identical units, is controlled to zero. The main assumption of having two identical units is rarely verified in practice and it has been noted that differences in the static characteristics can affect the stabilit...

A dynamic model for plant cell metabolism was used as a basis for a rational analysis of plant production potential in in vitro cultures. The model was calibrated with data from 3-L bioreactor cultures. A dynamic sensitivity analysis framework was developed to analyse the response curves of secondary metabolite production to metabolic and medium pe...

A perfusion small-scale bioreactor allowing on-line monitoring of the cell energetic state was developed for free-suspension mammalian cells. The bioreactor was designed to perform in vivo nuclear magnetic resonance (NMR) spectroscopy, which is a noninvasive and nondestructive method that permits the monitoring of intracellular nutrient concentrati...

Natural gas represents an environmentally attractive alternative to diesel and gasoline fuels to reduce all automotive emissions. However, a relatively high content of unburned methane in the exhaust gases outweighs these benefits. To treat such emissions, a counter-current type fixed bed autocyclic reactor (ACR) was designed and built for laborato...

The effects of Na-butyrate on the physiological behaviour and on the specific productivity of recombinant tissue plasminogen activator (t-PA) Chinese Hamster Ovary (CHO) cells were characterized. Batch cultures were performed in a 3.5-L bioreactor. Na-butyrate was added either at the mid-exponential growth phase (48 h) or at the end of the exponent...

The combustion of lean methane air mixtures in a catalytic flow reversal reactor (CFRR) is studied using a two dimensional heterogeneous continuum model, based on mole and energy balance equations for the solid (the inert and catalytic sections of the reactor) and the fluid phases. Following a design of experiments (DOE), many simulations were carr...

Overflow metabolism characterizes cells strains that are likely to produce inhibiting metabo-lites resulting from an excess of substrate feeding and a saturated respiratory capacity. The critical substrate level separating the two different metabolic pathways is generally not well defined. This paper proposes two non-model based extremum-seeking st...

Helper-dependent adenoviral vectors (HDVs) are the most promising adenoviral vectors for gene therapy treatments as well as vaccination strategies. However, the lack of a robust and efficient strategy to produce the HDV at high titers constitutes a major obstacle hindering the use of this promising technology at the clinical level. The HDV producti...

This study demonstrates real-time maximization of power production in a stack of two continuous flow microbial fuel cells (MFCs). To maximize power output, external resistances of two air-cathode membraneless MFCs were controlled by a multiunit optimization algorithm. Multiunit optimization is a recently proposed method that uses multiple similar u...

A previously developed kinetic metabolic model for plant metabolism was used in a context of identification and control of intracellular phosphate (Pi) dynamics. Experimental data from batch flask cultures of Eschscholtiza californica cells was used to calibrate the model parameters for the slow dynamics (growth, nutrition, anabolic pathways, etc.)...

Human adenoviral viral vector serotype 5 (AdV) is presently the primary viral vector used in gene therapy trials. Advancements in AdV process development directly contribute to the clinical application and commercialization of the AdV gene delivery technology. Notably, the development of AdV production in suspension culture has driven the increase...

A deposition efficiency model was developed in order to predict the effect of the dosage of retention aids (polymer and bentonite) on filler retention and validated with a pilot machine trial. The deposition efficiency is a function of the surface coverage of adsorbed and transferred polymer on solids (fiber and filler) and the surface coverage of...

A non-adiabatic fixed bed auto-cyclic reactor (ACR) consisting of two counter-current concentric compartments was designed and built for removing low concentrations of methane from exhaust gases from natural gas engines. The length was based on simulations by a simple heterogeneous one dimensional model using literature parameters and kinetic data,...

Safety requirements for adenoviral gene therapy protocols have led to the development of the third generation of vectors commonly called helper-dependent adenoviral vectors (HDVs). HDVs have demonstrated a high therapeutic potential; however, the poor efficiency and reliability of the actual production process hampers further large-scale clinical e...

In the multi-unit optimization method, the gradient is estimated using finite difference of the outputs of multiple identical units driven with inputs that are offset by a design parameter. For processes with non-identical units, it is shown that stability is not always guaranteed and that the scheme does not necessarily converge to the desired opt...

In this paper, an extremum-seeking controller is developed to steer a periodic system to orbits that maximize a functional of interest in the context of drug delivery optimization. The problem is posed as a real-time optimal trajectory generation problem in which the optimal orbit is computed using an extremum-seeking approach. Using the flatness p...

Extremum-seeking methods are unconstrained real-time optimization techniques that control the gradient to zero. The crucial difference between them lies in the gradient estimation method used. Multi-unit optimization technique proposes the use of a multiple units operated with an offset between them and the estimation of the gradient is by finite d...

Increased demands imposed by global market pressures, environmental constraints and energy costs have had a dramatic impact on the management and operation of processing systems in many sectors including chemical and petrochemical production plants. There is a significant thrust in North American companies to integrate science and technology into s...

In the stochastic context, expected value of the cost function is optimized either by changing the mean values of the manipulated variables or by reducing their variance. An extension is to look for an optimal shape for the entire probability density function (PDF). Though the use of asymmetric PDFs is proposed in the literature, no formal proof th...

In this paper, we pose and solve an adaptive extremum control problem to optimize the productivity of a van de Vusse reaction taking place in a tubular reactor governed by a set of nonlinear hyperbolic partial differential equations. Estimation and control algorithms that take into account control input constraints are developed by using a Lyapunov...

The operation of a paper machine relies on the close monitoring and control of several integrated units to ensure a high quality paper with the required specifications. In this paper, the retention control system in the wet-end of a paper machine is considered. The control objective is to maximize the retention of fines and fibres in the paper shee...