Imperial College London
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Professor Nina F. Thornhill

Faculty of Engineering, Department of Chemical Engineering

Emeritus Professor of Process Automation
 
 
 
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Contact

 

n.thornhill

 
 
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Location

 

ACE ExtensionSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
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212 results found

Thornhill NF, Oettinger M, Fedenczuk P, 1998, Performance assessment and diagnosis of refinery control loops, 3rd International Conference on Foundations of Computer-Aided Process Operations, Publisher: AMER INST CHEMICAL ENGINEERS, Pages: 373-379, ISSN: 0065-8812

Conference paper

Zhang J, Zhang S, Thornhill N, 1998, A governing equation based fault detection and diagnosis algorithm and its application in a chemical plant, Pages: 2472-2476, ISSN: 0743-1619

This paper describes a governing equation fault detection and diagnosis algorithm, which is based on Kramer (1987) and extended to deal with multiple faults. The algorithm is specifically designed to overcome disturbances and uncertainties in the process which might result in diagnostic instability. The approach is used to detect and/or diagnose the following faults: sensor faulty status of fails-high and fails-low, sticking valve, plant leaks, and other unanticipated or novel faults. The algorithm was installed on a distributed control system (DCS) of a PET plant in Dec. 1995, and continues to be used thus demonstrating the success of the fault detection and diagnosis approach. © 1998 AACC.

Conference paper

Sabry M, Thornhill NF, Midwinter JE, 1997, An analytical approach to charging mechanisms using control theory, ISSN: 0963-3308

In this paper we suggest how control theory may be used to model and analytically analyse telecommunication network charging mechanisms. We propose a control theory model which was used to analyse the dynamic (also known as 'Smart Market' or 'Free Market') charging scheme. We show how the analytical model was formalised and analysed to determine the long term or Steady State (SS), in control theory terminology, and short term or transient responses of the mechanism. We show how the system's performance varies as the parameters change. We also discuss the limitations of this method of analysis and in particular how this affects the results of the dynamic charging scheme analysis.

Conference paper

Thornhill NF, Hagglund T, 1997, Detection and diagnosis of oscillation in control loops, CONTROL ENGINEERING PRACTICE, Vol: 5, Pages: 1343-1354, ISSN: 0967-0661

Journal article

Chandwani RM, Pate ME, Savery J, Thornhill NF, Horstmann B, Hoare M, TitchenerHooker NJet al., 1997, The use of principal component analysis as a database mining tool for the exploratory diagnosis of chromatographic processes, BIOPROCESS ENGINEERING, Vol: 17, Pages: 229-234, ISSN: 0178-515X

Journal article

Gregory ME, Thornhill NF, 1997, The effects of aeration and agitation on the measurement of yeast biomass using a laser turbidity probe, BIOPROCESS ENGINEERING, Vol: 16, Pages: 339-344, ISSN: 0178-515X

Journal article

Dehghani M, Bulmer M, Gregory ME, Ison AP, Thornhill NFet al., 1996, On-line recognition of CO<inf>2</inf>exit gas profiles for operational harvesting time of intracellular enzyme products from S. cerevisiae, Bioprocess and Biosystems Engineering, Vol: 16, Pages: 50-55, ISSN: 1615-7591

This paper concerns the recognition of significant events in the trends from CO2exit gas profiles of a S.cerevisiae fermentation. Distinct changes in the on-line monitored variable, CO2exit gas concentration, are used to recognise identifiable phases of glucose depletion, biomass formation and the onset of intracellular enzyme production. Process automation for the harvesting of some intracellular enzyme products from S. cerevisiae is considered using on-line recognition of CO2exit gas peaks.

Journal article

Dehghani M, Bulmer M, Gregory ME, Ison AP, Thornhill NFet al., 1996, On-line recognition of CO2 exit gas profiles for operational harvesting time of intracellular enzyme products from S-cerevisiae, BIOPROCESS ENGINEERING, Vol: 16, Pages: 50-55, ISSN: 0178-515X

Journal article

Thornhill NF, Hutchinson RJ, Haughie BT, 1996, A probability chart for statistical process analysis, with applications, JOURNAL OF PROCESS CONTROL, Vol: 6, Pages: 161-167, ISSN: 0959-1524

Journal article

Bogle IDL, Cockshott AR, Bulmer M, Thornhill N, Gregory M, Dehghani Met al., 1996, A process systems engineering view of biochemical process operations, COMPUTERS & CHEMICAL ENGINEERING, Vol: 20, Pages: 943-949, ISSN: 0098-1354

Journal article

Thornhill NF, Sadowski R, Davis JR, Fedenczuk P, Knight MJ, Prichard P, Rothenberg Det al., 1996, Practical experiences in refinery control loop performance assessment, UKACC International Conference on Control '96, 2-5 September 1996, Pages: 175-180, ISSN: 0537-9989

The paper presents an example of the application of a control loop performance assessment technique in a refinery setting and diagnoses the causes of oscillations in flow loops.

Conference paper

DEHGHANI M, BULMER M, GREGORY ME, THORNHILL NFet al., 1995, MEASUREMENT VARIABILITY ANALYSIS FOR FERMENTATION PROCESS ASSAYS, BIOPROCESS ENGINEERING, Vol: 13, Pages: 239-243, ISSN: 0178-515X

Journal article

TURNER C, GREGORY ME, THORNHILL NF, 1994, CLOSED-LOOP CONTROL OF FED-BATCH CULTURES OF RECOMBINANT ESCHERICHIA-COLI USING ONLINE HPLC, BIOTECHNOLOGY AND BIOENGINEERING, Vol: 44, Pages: 819-829, ISSN: 0006-3592

Journal article

GREGORY ME, KEAY PJ, DEAN P, BULMER M, THORNHILL NFet al., 1994, A VISUAL PROGRAMMING ENVIRONMENT FOR BIOPROCESS CONTROL, JOURNAL OF BIOTECHNOLOGY, Vol: 33, Pages: 233-241, ISSN: 0168-1656

Journal article

THORNHILL NF, MANELA M, CAMPBELL JA, STONE KMet al., 1994, 2 METHODS OF SELECTING SMOOTHING SPLINES APPLIED TO FERMENTATION PROCESS DATA, AICHE JOURNAL, Vol: 40, Pages: 716-725, ISSN: 0001-1541

Journal article

Turner C, Thornhill NF, Fish NM, 1993, A novel method for the on-line analysis of fermentation broth using a sampling device, microcentrifuge and HPLC, Biotechnology Techniques, Vol: 7, Pages: 19-24, ISSN: 0951-208X

This paper describes a novel system for on-line sampling and analysis of whole broth from a fermenter. The system comprises a steam sterilisable sampling device, high speed microcentrifuge and HPLC. We present results characterising the separation efficiency of the microcentrifuge under different conditions, and illustrate the system with glucose and acetate data from an Escherichia coli fermentation using the system. The on-line measurements have been confirmed by off-line analysis. © 1993 Science & Technology Letters.

Journal article

ROYCE PN, THORNHILL NF, 1992, ANALYSIS OF NOISE AND BIAS IN FERMENTATION OXYGEN-UPTAKE RATE DATA, BIOTECHNOLOGY AND BIOENGINEERING, Vol: 40, Pages: 634-637, ISSN: 0006-3592

Journal article

Royce PN, Thornhill NF, 1992, Analysis of noise and bias in fermentation oxygen uptake rate data., Biotechnol Bioeng, Vol: 40, Pages: 634-637, ISSN: 0006-3592

The calculation of many derived fermentation variables such as the respiratory quotient (RQ) and mass transfer coefficient (K(L)a) requires the differences between the molar percentages of oxygen and carbon dioxide in the fermentor inlet and exit gas, called the %OUR and %CER. Noise and bias in %CER data is of order that in the exit gas carbon dioxide analysis. However, the relative amount of noise in the %OUR is one to two orders of magnitude greater than the noise in the raw oxygen analyses because the %OUR is calculated as a small difference between two large quantities. The noise in the %OUR is white with a Gaussian amplitude probability distribution of absolute standard deviation 0.0145. A chi-square filter of the %OUR data is shown to considerably improve the quality of the calculated RQ and K(L)a for a fermentation of Streptomyces clavuligerus.

Journal article

Stone KM, Roche FW, Thornhill NF, 1992, DRY WEIGHT MEASUREMENT OF MICROBIAL BIOMASS AND MEASUREMENT VARIABILITY ANALYSIS, BIOTECHNOLOGY TECHNIQUES, Vol: 6, Pages: 207-212, ISSN: 0951-208X

Journal article

MARSHALL CT, THORNHILL NF, LILLY MD, BUCKLAND BC, FISH NMet al., 1992, THE DESIGN AND IMPLEMENTATION OF A COMPARATIVE REASONING TOOL FOR FERMENTATIONS, 2nd IFAC Symposium on Modeling and Control of Biotechnical Processes 1992/5th International Conference on Computer Applications in Fermentation Technol, Publisher: PERGAMON PRESS LTD, Pages: 283-286, ISSN: 0962-9505

Conference paper

GREGORY ME, THORNHILL NF, 1992, USE OF A GRAPHICAL PROGRAMMING ENVIRONMENT FOR THE RAPID DEVELOPMENT OF CUSTOM SOFTWARE FOR FERMENTATION PROCESS CONTROL, 2nd IFAC Symposium on Modeling and Control of Biotechnical Processes 1992/5th International Conference on Computer Applications in Fermentation Technol, Publisher: PERGAMON PRESS LTD, Pages: 231-234, ISSN: 0962-9505

Conference paper

STONE KM, THORNHILL NF, ROCHE FW, FISH NMet al., 1992, A METHOD OF USING OFF-LINE MEASUREMENTS IN AN ON-LINE ESTIMATOR OF BIOMASS CONCENTRATION FOR A PENICILLIN FERMENTATION, AND ITS EFFECTS ON THE QUALITY OF THE ESTIMATES, 2nd IFAC Symposium on Modeling and Control of Biotechnical Processes 1992/5th International Conference on Computer Applications in Fermentation Technol, Publisher: PERGAMON PRESS LTD, Pages: 101-106, ISSN: 0962-9505

Conference paper

TURNER C, THORNHILL NF, FISH NM, 1992, ON-LINE SAMPLING AND ANALYSIS OF FERMENTATION BROTH USING A NOVEL SAMPLING DEVICE, MICROCENTRIFUGE AND HPLC, 2nd IFAC Symposium on Modeling and Control of Biotechnical Processes 1992/5th International Conference on Computer Applications in Fermentation Technol, Publisher: PERGAMON PRESS LTD, Pages: 339-342, ISSN: 0962-9505

Conference paper

ROCHE FW, THORNHILL NF, STONE KM, CARLEYSMITH SWet al., 1992, FAULT DETECTION AND IDENTIFICATION IN FERMENTERS, 2nd IFAC Symposium on Modeling and Control of Biotechnical Processes 1992/5th International Conference on Computer Applications in Fermentation Technol, Publisher: PERGAMON PRESS LTD, Pages: 323-326, ISSN: 0962-9505

Conference paper

ROYCE PNC, THORNHILL NF, 1991, ESTIMATION OF DISSOLVED CARBON-DIOXIDE CONCENTRATIONS IN AEROBIC FERMENTATIONS, AICHE JOURNAL, Vol: 37, Pages: 1680-1686, ISSN: 0001-1541

Journal article

Thornhill NF, 1990, Detecting Faults in Fermentation Processes, Computing and Control Engineering Journal, Vol: 1, Pages: 187-192, ISSN: 0956-3385

Fermentation processes are involved in the production of Pharmaceuticals (e.g. antibiotics), chemicals and bulk enzymes (e.g. citric acid, washing-powder enzymes), numerous foods and beverages, waste water treatment and in agriculture (e.g. silage). There are problems, particularly of process complexity and variability, that make fault detection and analysis in fermentation somewhat more difficult than in other process industries. The intention of this article is to illustrate present industrial practices of'high-value' fermentation processes, to survey the techniques that are beginning to be applied and to highlight what seem to be the most relevant developments. © 1990, The Institution of Electrical Engineers. All rights reserved.

Journal article

ROYCE PNC, ANDERSON MM, FISH NM, THORNHILL NFet al., 1989, THE USE OF CARBON-DIOXIDE EVOLUTION RATE IN CONSISTENCY CHECKING OTHER FERMENTER SENSOR OUTPUTS, 4TH INTERNATIONAL CONF ON COMPUTER APPLICATIONS IN FERMENTATION TECHNOLOGY ( ICCAFTA ), Publisher: ELSEVIER APPL SCI PUBL LTD, Pages: 443-447

Conference paper

THORNHILL NF, FUNG MYP, ROCHE FW, ROYCE PNC, ANDERSON MM, FISH NMet al., 1989, FERMENTATION FAULT-DIAGNOSIS USING ANALYTICAL REDUNDANCY, 4TH INTERNATIONAL CONF ON COMPUTER APPLICATIONS IN FERMENTATION TECHNOLOGY ( ICCAFTA ), Publisher: ELSEVIER APPL SCI PUBL LTD, Pages: 455-459

Conference paper

FISH N, THORNHILL N, 1988, MONITORING AND CONTROL OF FERMENTATION, CHEMICAL ENGINEER-LONDON, Pages: 31-&, ISSN: 0302-0797

Journal article

Fish N, Thornhill N, 1988, Monitoring and control of fermentation., CHEM. ENGR., ISSN: 0302-0797

Parameters influencing the fermentation process are defined. A simple model for microbial growth is given by a combination of the Monod equation (describing the dependence of the growth rate on the concentration of a limiting nutrient) and an equation associated with the consumption of that nutrient. Control of fermentation achieved by changing the chemical and physical environment in the reactor is discussed. Problems encountered in the development of new sensors for measurement of process variables are considered. The use of an efficient estimation filtering algorithm, such as an adaptive Kalman-Bucy filter, is discussed.

Journal article

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