Acknowledgements_2001_Fluidization-Dynamics

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Ac I<n owl edge me nts 
Many people have contributed to the continuing programme of research 
on which this book draws. First and foremost is Pier Ugo Foscolo, with- 
out whom there would be no question of the work having got off the 
ground. His was the driving force which turned what for me would prob- 
ably have been just a passing curiosity into a positive crusade. His insight, 
analytical skill and patient probing of the research literature eventually 
uncovered the elements of an accessible theory waiting to be assembled. 
We have worked together throughout the developments described in 
this book. 
That our initial focus was the forces acting on individual fluidized 
particles is an indication of the influence of Peter Rowe, who provided 
facilities, advice and constant encouragement throughout the early stages 
of this work in the Chemical Engineering Department laboratories at the 
University College London. He had long recognized the importance of 
such interactions and had subjected them to pioneering experimental 
study, of direct relevance to the present programme, many years earlier 
at the United Kingdom Atomic Energy Authority research laboratories at 
Harwell. 
One of the undoubted satisfactions of academic life is that of witnessing 
the progress of certain research students from eager beginners, struggling to 
make some sort of sense of the ill-defined open-ended problems they have 
been handed, to polished professionals, patiently explaining in simple terms 
to their advisors the steps taken in arriving at momentous conclusions. It 
does not happen all that often, but three clear instances in the course of 
this programme call for emphatic acknowledgement: Renzo Di Felice, 
Acknowledgements 
now Professor of Chemical Engineering at the University of Genova, 
and an established international authority on liquid fluidization, for his 
continuing active participation in experimental and theoretical aspects 
of the work too numerous to individualize; Stefano Brandani, formerly 
of the University of L'Aquila, now Reader in Chemical Engineering at 
University College London, for initiating the 'jump condition' analysis 
reported in Chapter 14 (his doctoral research was supervised by the late 
Gianni Astarita, whose inspired contributions to this and other areas of 
the work are also gratefully acknowledged); and Zumao Chen, who as my 
doctoral student at L'Aquila worked on aspects of slugging fluidization 
described in Chapter 15, and who subsequently, on his own initiative, 
embarked on the two-dimensional numerical simulation studies reported 
in Chapter 16, which have now come to represent the starting point for 
new programmes of computational research. 
From its inception, the work has involved close collaboration between 
the fluidization research teams of L'Aquila and UCL, accompanied by 
shuffling of staff and exchange of students. This remains as strong as ever 
thanks to the active participation of John Yates, who heads the UCL 
team. Past members of that group who deserve special mention for their 
contributions to the initial stages of the work are Simon Waldram and 
Ijaz Hossain; a more recent addition to the team is Paola Lettieri, who 
maintains strong connections with L'Aquila; David Cheeseman provides 
continuity and experimental expertise. Major contributors from L'Aquila 
include Sergio RapagnS., now Professor of Chemical Engineering at the 
University of Teramo, Nader Jand and Paolo Antonelli. 
I am especially grateful to Yuri Sergeev, Professor of Engineering 
Mathematics at the University of Newcastle, for his contribution to the 
'jump condition' studies, and also for his frequently solicited advice on 
technical problems encountered along the way. His careful reading of the 
original draft manuscript resulted in many suggestions for improvement, 
all of which have been adopted. 
Finally, the man who laid the foundation from which we were able to 
build: Graham Wallis. His unpublished 1962 paper, which he sent me 
following the appearance of our early applications of his stability criter- 
ion, contains a wealth of insight and analysis that, together with his book 
One-Dimensional Two-Phase Flow, we have drawn on repeatedly through- 
out the course of this work. His direct participation in the programme, at 
UCL in 1990, provided an invaluable opportunity to clarify aspects of the 
theory, and to repeat the key 'raining-down' experiments for measuring 
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Acknowledgements 
dynamic wave speed, which he devised and first performed in Peter 
Rowe's laboratory in Harwell, and only reported in the unpublished 
1962 paper; the method is described in Chapter 9, along with his original 
results and our more recent ones. 
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