India 2005

The 2005 Sterling Group lecture tour to India visited two centres – Mumbai and Bangalore – during the period Wednesday 31 August to Wednesday 7 September.

The tour party consisted of the Sterling Lecturer, Professor Julia E King CBE FREng, Principal of the Faculty of Engineering at Imperial College London, supported by a party of nine senior academics from member institutions of the Sterling Group. These institutions were the Universities of Bath, Durham, Leeds, Liverpool, Loughborough, Nottingham, Sheffield, Surrey and Warwick.

Mumbai

Professor King gave her Sterling Lecture on “Materials, Mimicry and MEMS: the future of flight?” to an audience of 350 at IIT Bombay. In addition the supporting party gave a series of presentations in the departments of the IIT with useful discussions being held with both staff and students. Presentations were also given in the University Institute of Chemical Technology (UICT) and in a number of local engineering colleges. A series of discussions were held with college principals and government officials.

Bangalore

Professor King gave her Sterling Lecture at the IISc, again to a very large and enthusiastic audience. The supporting party met staff of the IISc appropriate to their research disciplines and also gave a number of research presentations. Useful contacts were established which can be developed in future visits. Supporting lectures were given in local engineering colleges and Professor King visited the National Aerospace laboratories and General Motors Technology Centre.

The tour was organised in collaboration with the British Council with encouragement and financial support from the Royal Academy of Engineering, the Institution of Civil Engineers and the Institution of Mechanical Engineers.

Details of the Sterling Lecture and the supporting lectures are given below:-

STERLING GROUP LECTURE

Materials, Mimicry and MEMS: the future of flight?

Professor Julia King CBE FREng

Principal of the Engineering Faculty

Imperial College London

Over the past 50 years the aeroengine gas turbine, or ‘jet engine’, has transformed our lives: from the internationalisation of business, to how and where we spend our holidays. Today’s aeroengines are the result of many innovative, interdisciplinary developments involving materials, manufacturing and mechanical and electrical design. With the conflicting pressures of the increasing demand for air travel – growing at around 5% per annum – and the ever more urgent need to reduce CO2 emissions, there are plenty of exciting challenges ahead.

The first part of the lecture will review recent developments in gas turbine materials and design, including developments in widechord fan blades, single crystal turbine blades and composite-reinforced bladed rings (‘blings’).

Throughout the history of flight we have looked to the birds for inspiration. The peregrine falcon achieves an impressive 200 mph ‘speed of stoop’ when dropping to catch its prey, through dramatically reducing its surface area. In the 1960s, the ‘most expensive fighter plane ever’, the F111, was developed with swing wings to achieve a similar effect. In the 1990s patents and development work were reported for a new aircraft, ‘The Bird of Prey’, a more sophisticated and cost effective swing wing fighter. The mechanical, control, materials and maintenance challenges for such aircraft are enormous.

The next steps in the development of these ideas must be focussed on increasing efficiency and sustainability, not just increased performance. Dramatic reductions in drag are predicted from concepts such as the morphing plane, the flying wing, the electric aircraft and active flow and turbulence control. The second half of the lecture will examine some of the engineering and materials developments which could be critical to delivering ‘sustainable flight’: shape memory polymers, ‘gum metal’, advanced composites, MEMS devices in the form of miniature motors and actuators, new electrical materials and technologies.

We celebrated the centenary of flight in 2003. The challenges ahead for the next 100 years are even more important and exciting.

SUPPORTING LECTURES

Dr Sally E. Clift

Department of Mechanical Engineering, University of Bath

Title:- Investigating the Biomechanics of Articular Cartilage: The Role of Computer Based Modelling.

Abstract

Articular cartilage is the material that forms the bearing surfaces of synovial
joints. It has a high fluid content and yet supports loads that can be many
times body weight. There are two major load-carrying constituents to its internal
solid structure; fibres composed of collagen that are held in tension by large
hydropyllic molecules (called proteoglycans). Thus compression loading on the
cartilage surface produces compression of the proteoglycans, which increases
the tension in the collagen fibres, and releasing fluid which forces its way
through the porous-permeable cartilage matrix [1]. The mechanical response of
the cartilage layer is further complicated by an inhomogeneous distribution
of both the collagen and the proteoglycans through its thickness. In summary,
articular cartilage is inhomogeneous, anisotropic and non-linear in its behaviour.

Experimental characterisation of the mechanical response of articular cartilage has involved the application of compressive loading, indentation being the most popular configuration [2]. The data produced by such experiments is typically in the form of force-displacement relationships and has also been used to quantify the mechanical properties of the solid phase of the tissue [3]. These mechanical properties are termed biphasic constants, the terminology “biphasic” having been developed to refer to the two phases, solid and fluid, which make up the tissue.

The mathematical formulation of biphasic theory, which models loads transfer between the solid and fluid phases, was first developed by Mow and co-workers [4] and has undergone many enhancements [e.g. 5]. Other investigators have also highlighted the similarity between load transfer in cartilage and consolidation in soil mechanics, both processes being dominated by the flow of fluid through a porous-permeable matrix [6].

Biphasic theory and its companion formulations have been widely implemented in computer based stress analysis environments, principally using finite-element formulations. Industrially finite-element analysis is widely employed in biomechanical modelling and there are many commercial software packages available. The soil mechanics constitutive routines in one of these packages, known as ABAQUS, have specifically been validated for articular cartilage [7].

One major limitation encountered in all computer based modelling is that of the balance between the speed and the cost of the computers available. Fortunately, processing speed continues to increase and cost decrease thus allowing investigators to progressively develop more and more sophisticated representations of cartilage behaviour.

With developing confidence in these computer models has come a vast range of investigations into aspects of normal and disease cartilage behaviour. These include investigating the conditions governing cartilage failure [8]; effect of the mechanical environment on cartilage repair [9]; link between the response of cells and the mechanical response of the tissue [10]; optimum mechanical environment for the production of tissue engineered cartilage [11] and three dimensional joint contact [12].

References:

[1] Mow, VC, Proctor, CS, and Kelly, MA, (1989). Biomechanics of articular cartilage. In Basic Biomechanics of the Muskuloskeletal system, 2nd ed., eds. Nordin, MA, and Frankel, VH. Lea and Febiger, Philadelphia.

[2] Kempson, GE, Freeman, MAR, and Swanson, SAV, (1971), J Biomechanics, vol.4, pp239-250.

[3] Brown, TD, and Singerman, RJ, (1986). J Biomechanics, vol.19, no.8, pp.597-605.

[4] Kwan, MK, Lai, WM, and Mow, VC, (1990). J Biomechanics, vol.23, no.2, pp.145-155.

[5] Cohen, B, Lai, WM, and Mow, VC (1998). J Biomed Eng, vo1.120, pp.491-496.

[6] Prendergast PJ, van Driel WD, Kuiper JH.
Proc Inst Mech Eng [H] 1996;210(2):131-6

[7] Goldsmith AAJ, Hayes A & Clift SE (1995) “Modelling the response of biomaterials and soft hydrated biological tissues using soils consolidation theory”, ABAQUS Users Conference Proceedings, Paris 1995, pp305-319.

[8] Donzelli PS, Spilker RL, Athesian GA and Mow VC (1999). J Biomechanics vol 32, pp1037-1047

[9] Wu JZ, Herzog W and Hasler EM (2002),
Med Eng Phys. Vol 24, pp85-97.

[10] Guilak F and Mow VC (2000),
J Biomech. vol 12, pp1663-73.

[11] Shieh AC and Athanasiou KA (2003),
Ann Biomed Eng. Vol 31, pp1-11.

[12] Dunbar WL, Un K, Donzelli PS and Spilker RL
J Biomech Eng 2001 Aug;123(4):333-40

Dr Alan Dalton

School of Electronics and Physical Sciences, University of Surrey

Title:- Learning From Nature: High Performance Nanostructured Materials

Abstract
Individual Single Wall Carbon Nanotubes (SWNTs) have extraordinary properties. An important challenge is to develop practical technologies for transforming this intractable, low density soot into macroscopic assemblies such as composites, sheets or fibers having properties that exploit the extraordinary electrical and mechanical properties of the individual molecule. In particular, the fabrication of such assemblies, effectively using the spectacular modulus and failure strength of individual SWNTs coupled with other augmentative functions such as mechanical actuation would be a critical breakthrough to realizing their potential. In this talk, I will present two different approaches to achieving these goals.

Self-assembly and specificity in biological systems derives from control of surfaces. Proteins and other biological materials have evolved diverse complementary surfaces that enable interactions that lead to self-assembly and specificity. We have identified a variety of peptides that give SWNTs a customizable surface that not only facilitates separation and processing but can be interfaced with living cells. Moreover, through control of inter-peptide interactions, it is possible to assemble the hybrid nanostructures into macroscopic functional materials. We show that the self-assembly process of individual short SWNTs wrapped by folded polypeptides into structures is truly hierarchical.

We also describe spinning continuous SWNT composite fibers having a higher toughness than spider silk or any other natural or synthetic fiber, as well as high tensile strength and modulus. Normalized to density, the strength and modulus is twice that of steel wire. The energy needed to break these fibers is over five times higher than the best spider silk, and at least fifty times the energy to break the same weight steel wire. We make fiber supercapacitors from our spun fibers and weave them into textiles. Long cycle life is demonstrated, as well as a gravimetric energy storage density that approaches that of large supercapacitors operated over the same one-volt potential range. These nanotube composite fibers, which are easily woven or sewn into textiles, are quite interesting for artificial muscles and other electronic textile applications – such as distributed sensors, electronic interconnects, electromagnetic shielding, antennas, and batteries. Such applications and the origin of the attractive fiber properties will be discussed.

Professor John P R David

Department of Electronic and Electrical Engineering, University of Sheffield

Title:- Semiconductor Opto-Electronics

Abstract
The availability of reliable semiconductor lasers and photodetectors less than thirty years ago started a world wide interest in opto-electronics. This has lead to a multi-billion dollar industry and its increasing use in all areas of everyday life, such as entertainment, communications, military and medicine, means that it will continue to expand for the foreseeable future. The overwhelming majority of these devices are based on III-V semiconductors. Early opto-electronic devices such as the laser were based on relatively thick semiconductor layers. As the demands for better efficiency, higher speed and higher power increased, ‘quantum well’ structures with layers typically 10-100nm thick started to be utilised. Today, this evolution is continuing with ‘quantum dot’ structures, where dimensions are only a few nanometers, being actively investigated for advanced lasers and photodetectors. This presentation will review some of the challenges involved in realising the next generation of opto-electronic devices, and show some examples of the more unusual applications they are being used for.

Professor Animesh Jha

Institute for Materials Research, University of Leeds

Title:- “Let There be Light – And There was Light!”

Abstract

Light, known in modern Physics as Photons, has been the source of inspiration for many and will continue to be so in future. This vast subject of understanding of photons, although cannot be condensed into a short lecture, however the speaker dares and endeavours to explain how the modern fibre optics, lasers, and new physics and engineered materials continues to impact on our lives. The lecture will focus on the seminal discovery of guided waves, photonic bandgap, dispersion of photons, generation of stimulated photons as packets of energy, and nonlinear interactions; such as the Raman and Kerr-effects and their applications in life science. The role of materials engineering will be particularly emphasised in designing compact devices. Finally, the examples of such devices for creating a resourceful society will be explained particularly by emphasising the technological achievements in UK and its relevance for the future growth of Indian infrastructure and knowledge-based society.

Dr Edward Lester

School of Chemical, Environmental and Mining Engineering, University of Nottingham

Title:- Working at the Chemical Engineering/Chemistry Interface

Abstract

The talk will briefly outline what a chemical engineer does and how their expertise is needed in very diverse fields from chocolate to nuclear power, or drug production to water treatment. Chemical Engineering has been traditionally described as “the science of processing bulk materials on a commercial scale”. This therefore refers to high volume, low value products such as plastics, petrol and beer. The word ‘bulk’ has now disappeared as chemical engineers find themselves working in new fields such as pharmaceuticals and nanotechnology where the commercial value of 1 kg of product can exceed that of 100 tons of bulk scale materials like ammonia or terephthalic acid.

The talk will briefly highlight some successes and failures of collaborations between chemists and chemical engineers. Synergy between chemists and chemical engineering is crucial since the chemical engineer will often take a successful process from a research chemist and scale up or scale out to commercial scale. In order to function well, a chemical engineer must understand the chemist and vice versa. At University level, the USA has a much less well defined boundary between the chemist and the chemical engineer than the UK and this works to their advantage when working together. The new UK Government funded project called “Driving Innovation in Chemistry and Chemical Engineering” is an exciting opportunity to improve collaboration, particularly in the field of green and sustainable technology.

Supercritical fluids are seen as a green technology with potential applications for future industry. Whilst current commercial applications are relatively few, there are some emerging processes which use supercritical fluids and these will be discussed along with existing applications. Supercritical fluids are fluids that are pressurised and heated beyond their critical point (e.g. waters critical point is at 374oC and 218 atm). They are not gases or liquids but somewhere in-between. Their physical and chemical properties change at this point allowing numerous exciting new opportunities for chemical reactions. The engineering challenges are also interesting particularly when designing reactors to function at such conditions, especially when seeking to optimise mixing and movement through continuous reactors.

Professor Dennis L Loveday

Department of Civil and Building Engineering, University of Loughborough

Title:- “If You Want to Save Planet Earth . Become a Building Services Engineer!”

Abstract
Evidence is growing that planet Earth’s climate is changing, and that we all face an uncertain future in the years to come. Carbon dioxide released by the burning of fossil fuels for energy production is believed to be the main cause of climate change, and this is leading to global warming. In many countries, buildings are responsible for about 40% of national energy consumption, a large part of this being used for the cooling or heating of buildings to maintain people’s thermal comfort. For this reason, building services engineers take a leading role in combating global warming through energy-efficient design.

Against the above background, the lecture will address the important work undertaken by building services engineers in keeping people comfortable, healthy and productive in today’s energy-efficient buildings. This branch of engineering is of vital importance, since we spend about 90% of our lives indoors.

The relationship between human thermal comfort and energy use by buildings in the context of the above will be discussed. In particular, recent developments in our understanding of thermal comfort will be presented, together with a view of how buildings will have to become more energy efficient in future if we are to tackle the threat of climate change. Finally, a glimpse will be given of how building services engineering might develop in the far future.

Professor Asoke K Nandi

Department of Electrical Engineering and Electronics, University of Liverpool

Title:- You Do It All The Time – Signal processing and Communications

Abstract

Signal processing is one of the most fundamental necessities in our lives. For example, seeing, hearing and moving require signal processing. There are three basic questions in signal processing – detection, estimation and prediction; prediction is the most difficult of these all. To catch a cricket ball requires, amongst others, a good predictor. The human brain is the best general purpose signal processor currently available; it has the advantage of a very long evolution period and natural selection. Of course much of ‘artificial’ signal processing, that we do, deal with real world signals to (help) make sense in an automated way. Signal processing is an enabling discipline and as such contributes to many different disciplines. There are many application areas, like communications signal processing, biomedical signal processing, radar signal processing, genomic signal processing, etc. In this lecture I shall try to develop the basics of signal processing leading to some of the current questions and thinking.

Communications has changed our lives in so many ways that one could not have imagined 40 years ago. Yet this has all started at the end of 19th century and grown very rapidly and unimaginably. Signal processing has played, and will continue to play, an essential role in this. I shall outline a model for communications and explore some of the challenges.

In recent decades we have become rich in data, both in amount and in varieties. Rapidly we need to find ways of generating understanding and information. I shall outline how signal processing and machine learning are driving this process, indicating some successes and future challenges.

Dr Phillip Purnell

School of Engineering, University of Warwick

Title:- Cement – The Hidden Super-Material.

Abstract

Of all the materials in the world, none comes close, in terms of tonnes used, to concrete. The secret ingredient of concrete is cement – but how many of us know that much about it? This talk will introduce you to some of the secrets of cement: how it is made, the environmental consequences of its manufacture and its uniquely complex microstructure – it is, in fact, the original nano-material. But as well as being a structural material, it is a functional material. Its unique structure and flexibility means it has potential for use in a wide variety of other applications, from nuclear waste management to fire fighting. New technologies are also emerging that use cement-type processing methods to produce industrial ceramics. The latest research in these and other areas will be explored and give you a new perspective on this modest, humble super-material.

Dr Richard H Scott

School of Engineering, Durham University

Title:- Moment Redistribution Behaviour in Reinforced Concrete Beams

Abstract

Normal practice is to assume linear elastic behaviour when calculating the bending moment and shear force distributions in a reinforced concrete structure. This assumption is reasonable at low levels of loading but it becomes increasingly invalid at higher loads due to cracking and the development of plastic deformations. Design codes, such as Indian Standard IS 456, permit an elastic analysis to be used at the Ultimate Limit State (ULS) but acknowledge the non-linear behaviour by allowing design engineers to redistribute moments from one part of the structure to another subject to maintaining the rules of static equilibrium. The maximum permissible amount of moment redistribution is linked to the ductility of the reinforcement at the ULS. Implicit in the current use of moment redistribution is the assumption that sections possess sufficient ductility for the requisite plastic deformations to occur. However, it has been demonstrated that reinforcement strain at the ULS could be the controlling parameter in the more lightly reinforced types of members, such as slabs, and this prompted considerable discussion concerning the ductility requirements for steel reinforcement.

The presentation will describe an investigation which aimed to explore the nature of moment redistribution as load is increased on a structure and thus provide design guidance on the issues outlined above. To do this a series of two-span reinforced concrete beams, some containing strain gauged reinforcement, was tested to investigate moment transfer from the central support into the adjacent spans.

The strain gauged bars gave detailed information concerning the relationship between moment redistribution and bar strains. They demonstrated that significant levels of moment redistribution were developed at the Serviceability Limit State (SLS) when the reinforcement was behaving elastically. The total amount of redistribution was shown to be a combination of this elastic redistribution plus the redistribution caused by the post yield behaviour of the reinforcement (termed plastic redistribution). Thus the contribution of plastic redistribution, which is dependent on reinforcement ductility, was shown to be smaller than has previously been believed to be the case. The significance for practical design is that there is no case for reducing the maximum permissible limits for moment redistribution, as has been proposed by some, and that there is even a case for increasing the limits in certain circumstances. Further details will be given in the presentation.