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Publications (107)
The Sequential Multi-block PLS algorithm, called SMB-PLS, was recently proposed to improve interpretability of large multi-block data structures. It combines the strengths of Multi-block PLS (MB-PLS) and those of the Sequential Orthogonal PLS (SO-PLS) methods. It uses the two-level hierarchical structure of the first (i.e., block and super levels)...
he blasting of mining stopes is an important driver for mine seismicity. The factors controlling seismic response are not well understood. Mines mostly rely on the number of events and associated moment magnitudes. Geological and operational parameters are often neglected although known to be potential seismic drivers. A database was created for mo...
Undesired particulate agglomeration can create powder flow issues during manufacturing. Potassium chloride (KCl), a commercial product used in powder form as a potassium source, is known to agglomerate. The main objective is to develop a method to assess KCl agglomeration, then use it to understand its driving forces and the phenomena taking place....
This paper reports on the application of an acousto-ultrasonic (AU) scheme for the inspection of industrial-size carbon anode blocks used in the production of primary aluminium by the Hall-Héroult process. A frequency-modulated wave is used to excite the anode blocks at multiple points. The collected attenuated AU signals are decomposed using the D...
The large datasets resulting from operating HVAC&R systems are currently scrutinized to find ways to exploit the useful information that they might contain. In this work, historical data of a centrifugal water chiller over the course of more than 1.5 years of operation is used to learn about the system and to suggest modifications to its operation...
A fast and non-invasive near-infrared (NIR) imaging system is proposed to characterize biodegradable polylactic acid (PLA) films containing talc, and produced by extrusion film-blowing for packaging applications. The ultimate goal is to use the system on-line for quality control and after a post-processing thermal treatment (annealing). A set of PL...
The performance of the Hall-Héroult aluminium reduction process is strongly influenced by fluctuations of the baked carbon anode properties. The currently decreasing quality and increasing variability of the anode raw materials, coke and pitch, combined with the frequent changes by anode manufacturers to meet their specifications and reduce purchas...
In this study, composite films based on polylactic acid and talc were prepared by extrusion film blowing to determine the effect of annealing temperature, annealing time, and talc content on the morphology and gas permeability, as well as thermal and mechanical properties. The results showed that annealing temperature, annealing time, and talc cont...
A rapid and nondestructive machine vision sensor was developed for predicting the vibrated bulk density (VBD) of petroleum coke particles based on image texture analysis. It could be used for making corrective adjustments to a paste plant operation to reduce green anode variability (e.g., changes in binder demand). Wavelet texture analysis (WTA) an...
Reduction cell operation in primary aluminum production is strongly influenced by the properties of baked anodes. Producing consistent anode quality is more challenging nowadays due to the increasing variability of raw materials. Taking timely corrective actions to attenuate the impact of raw material fluctuations on anode quality is also difficult...
Baked anodes quality control is still mostly based on core sampling and characterization. Only a small proportion of the production can be tested by this method due to the costly, time consuming, and destructive nature of the analytical techniques. Furthermore, the core properties are not necessarily representative of those of the whole block. A ra...
Carbon anodes used in the aluminium industry were imaged through destructive and non-destructive testing (NDT) methods. For the latter case, computed tomography (CT), which has previously been used to map the 3D apparent density distribution, was extended to crack detection. Previous work has shown how to overcome technical hurdles related to crack...
The use of room temperature ionic liquids (IL) to assist bitumen extraction from oil sands in a waterless process was investigated. Four ILs were selected according to their ability to meet industrial requirements. Their impact on bitumen recovery and bitumen quality (fines content) was assessed through a mixed-level experimental design accounting...
Primary aluminum production is a very energy-intensive industry (~13 MWh per ton of aluminum produced), involving several complex processes within a plant. The paper presents a mass, energy and exergy analysis of an entire smelter. This work was motivated by the need to evaluate the potential for waste heat recovery/thermal integration in such a pl...
Cell morphology is an important macroscopic indicator of cellular physiology and is increasingly used as a mean of probing culture state in vitro. Phase contrast microscopy (PCM) is a valuable tool for observing live cells morphology over long periods of time with minimal culture artifact. Two general approaches are commonly used to analyze images:...
High quality baked carbon anodes contribute to the optimal performance of aluminum reduction cells. However, the currently decreasing quality and increasing variability of anode raw materials (coke and pitch) make it challenging to manufacture the anodes with consistent overall quality. Intercepting faulty anodes (e.g., presence of cracks and pores...
A soft-sensor model developed from historical carbon plant data and multivariate statistical methods was proposed in past work to obtain quick predictions of individual anode properties right after baking for quality control purposes. It could only be used for anodes baked at the coldest and hottest positions within the furnace due to the core samp...
A soft-sensor model developed from historical carbon plant data and multivariate statistical methods was proposed in past work to obtain quick predictions of individual anode properties right after baking for quality control purposes. It could only be used for anodes baked at the coldest and hottest positions within the furnace due to the core samp...
The baked anode quality control scheme used in most carbon plants consists of lab testing of anode core samples and monitoring weekly averaged properties. Both the low anode sampling rate and the averaging hide a significant amount of variability in the anode populations. Additional consideration depending on the sampling procedure needs to be take...
Magnetite grains from the Izok Lake (Nunavut, Canada) and the Halfmile Lake (New Brunswick, Canada) volcanogenic massive sulfide deposits, and from till covering the nearby areas were investigated using the scanning electron microscopy (SEM), electron probe micro-analyzer (EPMA), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-M...
The new Sequential Multi-block PLS algorithm is applied for establishing multivariate specification regions jointly on multiple types of raw materials. SMB-PLS distinguishes between process variations associated with raw materials from other orthogonal sources of variations such as operating policies. Combinations of raw material properties not com...
The objective of this work is to develop a rapid and nondestructive machine vision sensor to predict Vibrated Bulk Density (VBD) of coke aggregate samples based on their surface textural characteristics obtained by imaging. This information could be useful for ultimately making real-time process adjustments to reduce green anode variability. Coke s...
This work investigates the mechanical and aging properties of flax/glass fibers reinforced polypropylene hybrid composites. The mechanical properties as a function of reinforcement content show that adding glass fiber to polypropylene/flax composites improves tensile modulus and strength as well as impact resistance and hardness, but has negligible...
To improve understanding of the mixing phenomena resulting from the interaction between uniform magnetic fields and magnetic nanofluids, this work presents an optical investigation of the coherent structures generated by rotating magnetic nanoparticles in dilute nanofluid suspension submitted to uniform rotating magnetic fields. A microscopic visua...
The objective of this work is to develop a rapid and nondestructive machine vision sensor to predict Vibrated Bulk Density (VBD) of coke aggregate samples based on their surface textural characteristics obtained by imaging. This information could be useful for ultimately making real-time process adjustments to reduce green anode variability. Coke s...
The potential and effectiveness of near-infrared (NIR) hyperspectral imaging was investigated for rapid and nondestructive spectral-spatial inspection of functional multilayer films. A series of film samples having different combination of layers were used to demonstrate the sensor performance. Multivariate Image Analysis (MIA) was applied to NIR h...
Computed tomography is a powerful non-destructive technique providing a large amount of useful data to characterize carbon anodes. Previous works have used this technique on baked anode samples and some relationships for apparent density and total porosity as a function of X-ray attenuation coefficients have been proposed. In this paper, the use of...
An important issue for the anode manufacturers is the increased variability of the raw materials and its negative impact on baked anode quality. This variability could be reduced by timely corrective actions applied on selected manipulated variables at the green mill (i.e. process control). However, the lack of rapid sensors for measuring anode qua...
Combining color (spectral) and textural information often leads to improved performance of image-based sensors developed for different applications, such as process monitoring and prediction of process or product quality variables. A new method based on the Undecimated Wavelet Transform and Multivariate Image Analysis (UWT-MIA) is proposed in this...
An important issue for the anode manufacturers is the increased variability of the raw materials and its negative impact on baked anode quality. This variability could be reduced by timely corrective actions applied on selected manipulated variables at the green mill (i.e. process control). However, the lack of rapid sensors for measuring anode qua...
Computed tomography (CT) is a powerful non-destructive technique providing a large amount of useful data to characterize carbon anodes. Previous works employed this technique to characterize baked anode samples and some relationships have been proposed for apparent density and total porosity as a function of X-ray attenuation coefficients. In this...
We investigated the effect of various plasma parameters (relative density of atomic N and H, plasma temperature and vibrational temperature) and process conditions (pressure and H2/(N2+H2) ratio) on the chemical composition of modified poly(tetrafluoroethylene) (PTFE). The plasma parameters were measured by means of near-infrared (NIR) and UV-v...
Acquiring and processing phase-contrast microscopy images in wide-field long-term live-cell imaging and high-throughput screening applications is still a challenge as the methodology and algorithms used must be fast, simple to use and tune, and as minimally intrusive as possible. In this paper, we developed a simple and fast algorithm to compute th...
This study reports on using near-infrared (NIR) hyperspectral imaging for nondestructive spectral-spatial characterization of natural fiber composites. To illustrate the approach, maleic anhydride grafted polyethylene (MAPE)/hemp fiber composites were produced with different filler contents between 0 and 60%. Two different chemometrics methods base...
The baked anode quality control scheme used in most carbon plants consists of lab testing of anode core samples and monitoring weekly averaged properties. Both the low anode sampling rate and the averaging hide a significant amount of variability in the anode populations. Additional consideration depending on the sampling procedure needs to be take...
The baked anode quality control strategy currently used by most carbon plants based on testing anode core samples in the laboratory is inadequate for facing increased raw material variability. The low core sampling rate limited by lab capacity and the common practice of reporting averaged properties based on some anode population mask a significant...
Visual inspection of the amount of external marbling (intramuscular fat) on the meat surface is the official method used to assign the quality grading level of meat. However, this method is based exclusively on the analysis of the meat surface without any information about the internal content of the meat sample. In this paper, a new method using v...
This paper provides an overview of the history, methods and applications of multivariate image analysis methods as developed for use in the process industries. It presents a general framework for the methods and their applications and discusses them under image analysis methods that use only spectral features of the images, such as Multivariate Ima...
Liquid chromatography mass spectrometry (LCMS) is a powerful technique that could serve to rapidly characterize cell culture protein expression profile and be used as a process monitoring and control tool. However, this application is often hampered by both the sample proteome and the LCMS signal complexities as well as the variability of this sign...
As rotational molding of thermoplastic parts become more and more complex, understanding the fundamental processing aspects such as powder flow becomes important for good and uniform part quality. In this work, an image analysis technique is used to determine the effect of polymer powder particle size and distribution in a biaxially rotating spheri...
This work reports some observations made on particle motion in the transverse plane of rotating cylinders operated in the rolling regime. In particular, techniques were developed to estimate the transition between the active and stagnant layers. Based on the particle trajectory and velocity obtained, a new theoretical model based on the thin active...
Quebec's primary aluminium production industry consumes roughly 39 TWh of electricity per year and is accountable for roughly 7 million tons of CO2 equivalent. By tapping only a small portion of waste heat and integrating it inside the production facility itself, we can significantly reduce GHG emissions and energy consumption. Although the amount...
Several fundamental questions regarding cell growth and development can be answered by recording and analyzing the history of cells and their progeny. Herein, long-term and large-field live cell imaging was used to study the process of megakaryopoiesis at the single cell level (n = 9300) from human CD34+ cord blood (CB) in the presence of thrombopo...
A multiblock partial least squares (PLS) modeling approach is proposed in this Article for multivariate analysis and monitoring of aluminum reduction smelters and other electrochemical processes. These industries commonly operate from hundreds to a thousand of metallurgical reactors in parallel, which makes is difficult to build and maintain separa...
In this work, optical imaging is used to quantify the mixing dynamics of granular materials. Two different methods (GLCM and Multivariate RGB analysis) are combined to extract surface information and the time to achieve a specific degree of mixing. In particular, the effect of density, friction coefficient, surface quality and particle geometry was...
Introduction Process and data Multivariate analysis Results Conclusions Acknowledgments
Introduction Multivariate Process Monitoring Dataset Developing the Monitoring Strategy Case Study Conclusion
This study examines the ability of chemometrics methods, namely multivariate image analysis (MIA) and Grey Level Co-occurrence Matrix analysis (GLCM), to extract meaningful information from visible and near-infrared spectral images of extruded wood/plastic composite materials for predicting spatio-temporal variations in their properties. The sample...
This paper reports some observations on the behaviour of a binary particle bed consisting of a mixture of small and large particles in the axial plane of a rotating drum. The effects of Froude number, particle diameter, filling ratio and initial particle concentration on axial segregation are evaluated using polymer powders. The results show that t...
Aluminum reduction cells performance are affected by many factors. In order to efficiently understand possible causes of performance upsets, all major sources of variations have to be monitored. This implies monitoring all anode and alumina properties, as well as pot state and manipulated variables, while also taking into account pot design or inte...
Prebaked anode quality is available through a weekly average of core sample laboratory measurements. Unfortunately, long delays between production and results (approximately 4-6 weeks) can lead to poor abnormal operation and faulty anode detection, and difficult process control. Extensive raw material and process data are available at Alcoa Descham...
A packed bed operated with descending gas–liquid cocurrent flows in slanted configuration to force trickle flow pattern to segregate due to gravity was studied, in addition to dependences to inclination angle of liquid saturation and pressure drop. Inception of pulse flow regime could take place regardless of inclination angle and the transition fr...
In several process industries including mineral processing, where the materials are solids or slurries, some important measurements
cannot be obtained using standard instrumentation (e.g., flow, temperature, pressure, pH, power draw, etc.), but can be visually appraised, and could be automatically quantified using machine vision techniques. In gene...
Megakaryocytes (MK) undergo polyploidization through endomitosis, a mitotic process that ends prematurely due to aborted cytokinesis. To better understand this and other events associated with MK differentiation, we performed long-term and large-field live cell imaging of human MKs derived in cord blood (CB) and bone marrow (BM) CD34(+) cell cultur...
Aluminum is produced inside metallurgical reactors known as pots that are replaced at the end of their service life. New pots
are preheated, started, and then enter a period known as early operation in which different control strategies are used before
entering regular operation. It is known that how preheating, start-up, and early operation are pe...
In this work, the mixing quality of a multi-component blend of particles is determined using Multivariate Image Analysis of RGB images combined with the Grey Level Co-occurrence Matrix (GLCM) texture analysis. The mixing dynamics and flow behavior are studied in terms of mixing homogeneity and time to achieve equilibrium for binary, ternary and qua...
In the production of rotomolded parts, the distribution of particle sizes in the form of polymer powder is highly important to produce parts of good quality. In the case of polymer blends, the particle size distribution becomes even more important to assure that good mixing occurs before the polymer melts. In this work, the mixing of free flowing p...
A PLS-bootstrap-VIP approach is proposed as a simple wavelength selection method, yet having the ability to identify relevant spectral intervals. This approach is particularly attractive for wavelength selection within hyperspectral images due to its simplicity and relatively low computational cost compared to more sophisticated interval search met...
A visible−near-infrared (VIS-NIR) hyperspectral imaging sensor is proposed for online nondestructive monitoring of polymer film blends produced by extrusion blowing. Such a sensor provides a much higher spatial resolution of analysis compared to probes or probe arrays, which should help in detecting smaller localized defects inducing poor film qual...
Modern high-throughput proteomic platforms allow incomparable protein mixture resolution and identification. However, such sophisticated facilities are expensive and not always accessible for routine analysis of simple mixtures. In this paper, we propose a simple methodology, based on detection of intact, nondigested proteins by LC coupled to singl...
As rotational molding parts become more and more complex, understanding how the polymer moves inside a rotating mold is important for good parts quality. Since the polymer is in a powder form, a distribution in particle sizes is present and each size can have very different flow characteristics. In this work, powder mixing and flow behavior are stu...
Spectral imaging is increasingly used to develop rapid and non-invasive analytical sensors in a variety of fields. This paper discusses the ability of chemometrics methods, such as multivariate image analysis (MIA) and wavelet texture analysis (WTA), to extract meaningful information from spectral images, enabling the user to monitor subtle spatio-...
A rapid and non-intrusive on-line NIR imaging sensor is developed for monitoring spatio-temporal crystallinity variations across the surface of polymer films. A multivariate image analysis and regression (MIA/MIR) approach is proposed and compared with standard NIR calibration techniques using averaged spectra or second order derivatives combined w...
Rotary dryers are widely used in chemical and mineral processes due to their flexibility and simplicity of operation. Nevertheless, the comprehension of the basic phenomena taking place in this type of dryer is still of great interest. In order to better understand the phenomenological behaviour of the process and to assess product moisture control...
The potential for qualitative representation of trends in the context of process diagnosis and control is evaluated in this paper. The technique for qualitative description of the data series is relatively new to the field of process monitoring and diagnosis and is based on the cubic spline wavelet decomposition of the data. It is shown that the as...
In this work, the transverse mixing of free flowing particles in a horizontal rotating drum has been studied. Special attention is given to the initial moments of mixing and the transition from a standstill to a fully developed rolling regime. The parameters studied include rotational frequency (1.3 to 4.6 rpm), loading (15 to 50%), relative black/...
In this paper, the use of different image analysis techniques is investigated for predicting alumina content of anode cover materials used in primary aluminum smelters. This approach is proposed in to order to allow on-line estimation of alumina content for feedback control purposes, which is not currently possible due to the long time delays and l...
The potential for qualitative representation of trends in the context of process diagnosis and control is evaluated in this paper. The technique for qualitative description of the data series is relatively new to the field of process monitoring and diagnosis and is based on the cubic spline wavelet decomposition of the data. It is shown that the as...
Anode cover material, a mixture of secondary alumina and electrolytic bath, is used to cover newly set anodes and to fill crust holes following crust meltdown. However, maintaining a constant composition over time is difficult since bath mass balance, from a potroom point of view, must be respected. Alumina and bath, particulate products with diffe...
In the production of rotomolded parts, the distribution of particle sizes in the form of polymer powder is important to produce parts of good quality. In the case of polymer blends, the particle size distribution becomes even more important to assure that a good mixing can occur before the polymer melts. In this work, the mixing of free flowing pol...
Analysis of reduction cells performance could be a hard task for process engineers. One has to handle many highly correlated variables, where time lags and missing values must be covered. Performing an efficient analysis of complex potroom data does not always lead to good answers, for example; when an important production drift occurs. It is often...
Variations in run-of-mine ore properties such as size, composition, and grindability strongly affect AG and SAG mills performance. In the past, most efforts to track and control these variations have focused on developing on-line size analysis using vision systems to reduce power consumption and avoid mill overload. To improve ore sorting/blending...
After agglomeration, iron oxide pellets are sintered in continuous furnaces to develop the mechanical properties required by iron making plants. In the first zones of the furnace, pellets are dried by the hot recycled gas. The objective of the study is to model their drying kinetics. For that purpose, individual pellets, instrumented for temperatur...
In this paper, two approaches to data mining of time series have been tested and compared. Both methods are based on the wavelet decomposition of data series and allow the localization of important characteristics of a time series in both the time and frequency domain. The first method is a common method based on the analysis of wavelet power spect...
The paper proposes a method to reconcile industrial data with mass balance constraints in a context where species leaching occurs, and assuming steady-state operating conditions. The various data levels correspond to the various phases and species within the phases: for instance slurry, ore, aqueous and carbon phases, particle size classes, mineral...
A simulator was developed to reproduce the operation of a gold leaching circuit. The ore is described by its mineral composition and precious metal content. The simulator allows adjustment of the ore size distribution, species distribution through the size intervals and distribution of gold grains exposed surface. A parallel bypass and Cholette-Clo...
Carbon anodes used in the production of primary aluminium have to be covered with a layer of particulate materials, a mixture of alumina and crushed electrolytic bath. Alumina composition analyses of this material are performed daily in laboratory on a very limited number of samples. However, analyses results from this small number of samples do no...