Publications by Michael Amrhein

On decoupling rate processes in chemical reaction systems - Methods and applications

Michael Amrhein, Dominique Bonvin, Julien Léo Billeter, Diogo Filipe Mateus Rodrigues

Models of chemical reaction systems can be complex as they need to include information regarding the reactions and the mass and heat transfers. The commonly used state variables, namely, concentrations and temperatures, express the interplay between many p ...

2018

Fast Estimation of Plant Steady State for Imperfectly Known Dynamic Systems, with Application to Real-Time Optimization

Michael Amrhein, Dominique Bonvin, Julien Léo Billeter, Diogo Filipe Mateus Rodrigues

2018

Concept and Applications of Extents in Chemical Reaction Systems

Michael Amrhein, Dominique Bonvin, Julien Léo Billeter, Sriniketh Srinivasan, Diogo Filipe Mateus Rodrigues

Models of chemical reaction systems can be quite complex as they typically include information regarding the reactions, the various transfers of heat and mass, as well as the effects of the inlet and outlet flows. It is well known that a linear transformat ...

2017

Constrained multi-rate state estimator incorporating delayed measurements

Michael Amrhein, Dominique Bonvin, Sriniketh Srinivasan

Frequent and accurate concentration estimates are important for the on-line control and optimization of chemical reaction systems. Such estimates can be obtained using state estimation methods that fuse frequent (fast) delay-free on-line measurements with ...

IEEE2017

ALS Scheme using Extent-based Constraints for the Analysis of Chemical Reaction Systems

Michael Amrhein, Dominique Bonvin, Julien Léo Billeter

Multivariate curve resolution via alternating least squares (ALS) is used to resolve the concentration profiles C and the pure component spectra E of S species from the multivariate absorbance data A, assuming the bilinear model ...

2016

Fast Estimation of Plant Steady State, with Application to Static RTO

Michael Amrhein, Dominique Bonvin, Julien Léo Billeter, Diogo Filipe Mateus Rodrigues

Experimental assessment or prediction of plant steady state is important for many applications in the area of modeling and operation of continuous processes. For example, the iterative implementation of static real-time optimization requires reaching stead ...

2016

Incremental Identification of Reaction Systems - A Comparison between Rate-based and Extent-based Approaches

Michael Amrhein, Dominique Bonvin, Nirav Pravinbhai Bhatt

An incremental identification approach for determining the kinetics of homogeneous reaction systems from transient concentration measurements has been developed in previous work (Marquardt, W. Chemical Engineering Research and Design 83(A6), 561–573, 2005) ...

Elsevier2012

Minimal State Representation for Open Fluid-Fluid Reaction Systems

Michael Amrhein, Dominique Bonvin, Philippe Müllhaupt, Nirav Pravinbhai Bhatt

Reaction systems are typically represented by first-principles models that describe the evolution of the states (typically concentrations, volume and temperature) by means of conservation equations of differential nature and constitutive equations of algeb ...

Ieee Computer Soc2012

On multivariate calibration with unlabeled data

Michael Amrhein, Dominique Bonvin, Pamandeep Singh Gujral

In principal component regression (PCR) and partial least-squares regression (PLSR), the use of unlabeled data, in addition to labeled data, helps stabilize the latent subspaces in the calibration step, typically leading to a lower prediction error. A non- ...

Wiley-Blackwell2011

Incremental Identification of Reaction and Mass-Transfer Kinetics Using the Concept of Extents

Michael Amrhein, Dominique Bonvin, Nirav Pravinbhai Bhatt

This paper proposes a variation of the incremental approach to identify reaction and mass-transfer kinetics (rate expressions and the corresponding rate parameters) from concentration measurements for both homogeneous and gas-liquid reaction systems. This ...

2011

Robust gain-scheduled blending control of raw-mix quality in cement industries

Michael Amrhein, Alireza Karimi, Vinicius De Oliveira

This paper addresses the control of the blending process in cement industries. This process can be modeled by a nonlinear multivariable system with large parametric uncertainty. Using a specific transformation, a linear parameter varying (LPV) model with s ...

Ieee Service Center, 445 Hoes Lane, Po Box 1331, Piscataway, Nj 08855-1331 Usa2011

Extents of reaction and flow for homogeneous reaction systems with inlet and outlet streams

Michael Amrhein, Dominique Bonvin, Nirav Pravinbhai Bhatt

This paper proposes two transformations for homogeneous reaction systems with inlet and outlet streams that allow isolating three distinct parts of the state vector, namely, the reaction variants, the reaction invariants but inlet- ﬂow variants, and the re ...

2010

Identification of reaction and mass-transfer rates in gas-liquid reaction systems

Michael Amrhein, Dominique Bonvin, Nirav Pravinbhai Bhatt

This paper deals with the identification of reaction and mass-transfer rates from concentrations measured in gas-liquid reaction systems. It is assumed that the reactions take place in the liquid bulk only. The identification proceeds in two steps: (i) est ...

IIT-Madras2010

Extents of Reaction, Mass Transfer and Flow for Gas-Liquid Reaction Systems

Michael Amrhein, Dominique Bonvin, Nirav Pravinbhai Bhatt

For gas-liquid reaction systems with inlet and outlet streams, this paper proposes a linear transformation to decompose the numbers of moles vector into five distinct parts, namely, the extents of reaction, the extents of mass transfer, the extents of inle ...

2010

Framework for explicit drift correction in multivariate calibration models

Michael Amrhein, Dominique Bonvin, Pamandeep Singh Gujral

Latent-variable calibrations using principal component regression and partial least-squares regression are often compromised by drift such as systematic disturbances and offsets. This paper presents a two-step framework that facilitates the evaluation and ...

2010

Minimal state representation of homogeneous reaction systems

Michael Amrhein, Dominique Bonvin, Nirav Pravinbhai Bhatt

Minimal state representations are parsimonious models having no redundant states. For homogeneous reaction systems with S species, R independent reactions, p independent inlet streams and one outlet stream, a nonlinear transformation of the numbers of mole ...

2010

Drift Correction in Multivariate Calibration Models Using On-line Reference Measurements

Michael Amrhein, Dominique Bonvin, Pamandeep Singh Gujral

On-line measurements from first-order instruments such as spectrometers may be compromised by instrumental, process and operational drifts that are not seen during off-line calibration. This can render the calibration model unsuitable for prediction of key ...

2009

Data Reconciliation of Concentration Estimates from Mid-Infrared and Dielectric Spectral Measurements for Improved On-Line Monitoring of Bioprocesses

Michael Amrhein, Dominique Bonvin, Ian William Marison, Urs von Stockar, Michal Dabros

Real-time data reconciliation of concentration estimates of process analytes and biomass in microbial fermentations is investigated. A Fourier-transform mid-infrared spectrometer predicting the concentrations of process metabolites is used in parallel with ...

2009

Classification of magnetic resonance images from rabbit renal perfusion

Michael Amrhein, Dominique Bonvin, Pamandeep Singh Gujral

The feasibility of using chemometric techniques for the automatic detection of whether a rabbit kidney is pathological or not is studied. Sequential images of the kidney are acquired using Dynamic Contrast-Enhanced Magnetic Resonance Imaging with contrast ...

2009

Partial least-squares regression with unlabeled data

Michael Amrhein, Dominique Bonvin, Pamandeep Singh Gujral

It is well known that the prediction errors from principal component regression (PCR) and partial least-squares regression (PLSR) can be reduced by using both labeled and unlabeled data for stabilizing the latent subspaces in the calibration step. An appro ...

2009