Department of Engineering

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Research news

PowerSi Technologies wins prizes

PowerSi Technologies founded by Dr Patrick Palmer (left), and two of his former PhD students, Dr Zhihan Wang and Dr Yalan Wang.

PowerSi Technologies Limited, a spin-out from the Department of Engineering, have won prizes at both the 2008 Cambridge University Entrepreneurs (CUE) £5K Challenge and the 21st Century China UK Entrepreneurship Competition.

Last October 336 teams entered the serial CUE Challenge business plan competitions. The team of PowerSi Technologies won both Technology Prize and Cleantech Prize as announced at the recent prizegiving ceremony, pitching in front of a panel of Cambridge entrepreneurs, business angels and venture capitalists. The team also won the first place in the 21st Century China UK Entrepreneurship Competition out of more than 200 entries from both the UK and China. The team presented at the China UK Showcase held in London in June with prestigious delegates from both the UK and China. The two prizes include £12,000 cash, free IP services worth £5,500 and other free advisory services.

PowerSi Technologies was recently founded by Dr Patrick Palmer, Reader in Electrical Engineering, and two of his former PhD students, Dr Zhihan Wang and Dr Yalan Wang, from the Electronics, Power and Energy Conversion group of the Department. Their winning business plan is to promote the technologies for power semiconductors and controllers in renewable energy applications.

PowerSi Technologies has developed and patented a technology AVC (Active Voltage Controller) that will revolutionise energy conversion through the intelligent control of power semiconductor devices. By using AVC, electric energy can be more efficiently transformed from one form into the other form (e.g. from AC to DC). Zhihan says "Our Active Voltage Controller, the most intelligent controller today, will reduce the total cost of a conversion system by 40%, improve the efficiency by 10% and enhance reliability. Our entry market is industrial converters of renewable energy applications, including wind power, solar energy and hybrid vehicles. The total available market of controllers in these three sectors is worth $1.3bn in 2008, of which we will take 20% within 5 years."

Research on the control of power semiconductors has been led by Dr Palmer since the early 1990s. The AVC has been developed as an intelligent and cost-efficient method to drive and control power semiconductor devices, including Insulated-Gate Bipolar Transistors or IGBTs which are semiconductor devices, noted for high efficiency and fast switching, and Metal–Oxide–Semiconductor Field-Effect Transistors or MOSFETs which are devices used to amplify or switch electronic signals. The AVC exerts intelligent feedback control on conventional power devices for the first time that enables them to have user-defined and well-behaved switching performance. The team has been actively cooperating with Cambridge Enterprise on the patent filing and commercialisation.

The AVC demonstrator products are currently in production and expected to be adopted to control tens of IGBTs in series connection in a large-capacity Static Compensator in China which is a national key project funded by the Ministry of Science and Technology of China. This will be a big challenge in the power electronics field.

PowerSi Technologies was also selected by Innovator Capital to pitch at CleanEquity Monaco, an investor summit in March.

For more information, please contact Dr Zhihan Wang: zw220 AT

The Future Is 3-D Liquid Crystals

Tim Wilkinson uses an Olympus BR11 microscope to display the switching of a lenslet array in his laboratory.

Dr. Tim Wilkinson from the Department's Photonics Research Group has made an exciting breakthrough, he has combined liquid crystals with vertically grown carbon nanotubes to create a reconfigurable three-dimensional liquid crystal device structure. This offers completely new ways to control molecules in liquid crystals, allowing the crystals to move in a variety of directions to create optical components such as lenslet arrays. This technology is still in the early phase of development, but recent trials indicate that potential applications exist in adaptive optical systems such as the wavefront sensors used in optometry, digital video cameras, optical diffusers and emerging head-up display devices.

Liquid crystal (LC) molecules are shaped so that they naturally align with each other if put in a cell to form an optically active pixel. In a display device the liquid crystal pixel is used to change the polarisation of the light passing through it and the degree of change (seen as contrast) is done through an applied voltage onto electrodes at the top and bottom of the cell. The applied voltage makes the LC molecules rotate in the cell and changes their orientation with respect to the light passing through the cell. This cell geometry limits the ways in which the light can interact with the liquid crystal molecules to a 2 dimensional plane. If we add a 3 dimensional element to the lower electrode we can change the way in which the voltage interact with the LC molecules to make a 3 dimensional optical structure. A simple example is shown on the top image on the right handside, where a thin conducting rod is added to the lower electrode to create a Gaussian electric field profile which forms a tiny microlens in the LC material. With many rods it is possible to create array of micro lenses which can have a focal length that varies with the applied voltage. Such a reconfigurable array has many uses in adaptive optical systems and 3D holographic displays.

Talking about his work Tim says "My idea is to combine two well established technologies, liquid crystals and nanotechnology to make a new hybrid device. The LCs has the ability to create a reconfigurable optical modulator (such as would be seen as 2D pixels in a liquid crystal device (LCD)) with the vertically grown multiwall carbon nanotubes (MWCNT) which act as a 3D electrode structure. In a traditional LC device (such as a display screen) the pixel electrodes are above and below the LC and allow it to be switched in a simple way. In the hybrid device the lower electrode is the MWCNT grown on silicon which sticks out from the surface into the 3rd dimension. This is also a more complex electric field profile which in turn creates a more complicated 3D refractive index profile in the LC layer. Hence we can make very complicated optical elements using a very simple device structure and an applied voltage to switch it.

An example is when the MWCNTs on the lower electrode surface are all connected and switched with the same voltage. The resulting electric field profile surrounding each MWCNT electrode is Gaussian in shape which creates a Gaussian refractive index profile in the LC layer. This looks optically like a tiny lens which is centred on each MWCNT, hence for an array of CNTs spaced 10μm apart we end up with an array of microlenses 10μm apart. By changing the voltage applied to the CNTs we can switch the micro lenses on and off and also vary their focal length. There are many applications for such a switchable microlens array such as in adaptive optical systems where the ability to self focus a lens is important or as an active diffuser in a head mounted display system.

More importantly this breakthrough changes the way in which we think about creating liquid crystal devices. It allows us to include a 3D element to the design of modulating characteristics. If we address each individual CNT with a separate voltage then we can build more complex 3D refractive index profiles similar to those you would see in a full 3D photographically recorded hologram. However the difference with the LC/CNT device is that the hologram can be changed dynamically as you would change an image on a LCD. This allows full 3D displays to be built using this sort of technology."

Articles on this research appeared in EuroPhotonics trade magazine (August 2008), in Advanced Materials and in Advanced Imaging Magazine (January 2009).

Design of a timber framed multi-storey car park

Benjamin Torrance

Benjamin Torrance has won 1st prize in the TRADA (Timber Research and Development Association) Timber in Construction Student Prize for his 4th Year MEng project. Benjamin will receive prize money of £1000.

Timber has been used to build fantastic structures for thousands of years, and I hope we shall continue to see exciting new ways of incorporating it into structural and architectural design.

Benjamin Torrance

The project grew out of research in the Department into timber-concrete composite flooring. It was a chance to put the findings of this research into a design situation, investigating the commercial and structural viability of timber in construction by following a brief to design a 500 space multi storey car park.

The structure is primarily glue-laminated timber columns and beams, based around a 15.5m x 4.8m column grid. A composite floor system consisting of a concrete deck slab secured onto the timber beams with coach screws provides an efficient flooring system. The concrete helps to stiffen the structure, whilst the use of timber for the bulk of the structural elements within the building provides a lower embodied carbon structure.

The use of this composite flooring enabled long span column free parking space to be achieved in a structure type usually dominated by steel and reinforced concrete. Furthermore, using timber reduced the structure's embodied carbon by around 80% compared to a steel frame.

The design was based on the Eurocode 5 design code for timber, but finite element analysis was used to further investigate plasticity in the partially composite behaviour of the timber and concrete system. The results are an encouragement to engineers to embrace timber design with the new codes. Benjamin says; 'Timber has been used to build fantastic structures for thousands of years, and I hope we shall continue to see exciting new ways of incorporating it into structural and architectural design.'

Benjamin would like to thank Richard Persaud for access to his PhD work on timber-concrete composite flooring systems, and his supervisor Digby Symons and Ramboll Whitbybird for their support and advice.

Engineering student picks up UK's first ever Best Student Paper Award at IEEE International Conference on Sensors

Ibraheem Haneef

Ibraheem Haneef, a PhD student in the High Voltage Microelectronics (HVM) Group in the Electrical Engineering Division, is the first ever student from the UK to win a best paper award at the Institute of Electrical and Electronics Engineers (IEEE) Sensors conference.

He won the third place Best Student Paper Award at the 7th IEEE International Conference on Sensors that was recently held at Lecce, Italy. His paper entitled "Laminar to Turbulent Flow Transition Measurement Using an Array of SOI CMOS MEMS Wall Shear Stress Sensors" was one of the six finalist student papers (out of sixty papers) selected by a panel of international experts. During the conference, the authors of the six finalists papers were asked to give a six minute special presentation to the selection committee, which chose the best three papers based upon the originality, quality of research work and quality of written and oral presentation of the authors. The other co-authors with Ibraheem, also from the Department, include S. Zeeshan Ali and Dr Florin Udrea from the HVM Group, and John Coull and Professor Howard P. Hodson from the Whittle Laboratory.

The IEEE Sensors conference is the most prestigious international forum for the presentation, discussion, and exchange of information in the field of sensors.

Ibraheem Haneef is currently working under the supervision of Dr Florin Udrea (Head of HVM Group) in collaboration with Professor Howard Hodson (Head of Whittle Laboratory) on SOI CMOS based MEMS flow sensors. The novel flow sensors developed by Ibraheem during his PhD research have outstanding performance compared to the conventional sensors. These sensors have potential applications in aerospace industry for wall shear stress (or skin friction drag) measurement and in automotives as mass air-flow (MAF) sensor. Due to their extremely small size, these sensors can also be used for prognosis and diagnosis of coronary artery disease. A number of companies have shown keen interest in using these novel sensors that have already been IP protected through a UK and International patent application filed with UK Patent Office.

These sensors are being commercialised by Cambridge Enterprise, whose role is to help University of Cambridge inventors, innovators and entrepreneurs make their ideas and concepts more commercially successful. For further information on the commercial applications for these sensors please contact Dr Zlatka Stoeva at Cambridge Enterprise:

New 'Innovation and Knowledge Centre' worth a total of £17million awarded to Engineering Department

Funding has been announced for two major new research centres, one of which is to be based at the Department of Engineering. This 'Innovation and Knowledge Centre' (IKC) on Smart Infrastructure and Construction will combine business knowledge with the most up-to-date research to harness the full potential of emerging technologies - ensuring the UK is first to develop this cutting-edge research. The centre is funded by the Engineering and Physical Sciences Research Council (EPSRC) and the Technology Strategy Board, and by industry.

Professor Robert Mair, the Principal Investigator of the grant, says "Much of our infrastructure is more than 100 years old. Resilience against systemic failure of UK infrastructure is significantly weakening through ageing. Infrastructure owners therefore have a strong interest in emerging technologies in sensors and data management, to quantify and define the extent of ageing and the consequent remaining design life of their infrastructure. The application of emerging technologies to advanced health monitoring of existing critical infrastructure assets will address these needs, improve the management of infrastructure and reduce the risk of failure. By providing cradle-to-grave health monitoring, combined with innovative manufacturing processes, these technologies will also lead to more efficient and economic construction of new infrastructure. The IKC will focus on smarter construction and production processes, employing the latest research developments in intelligent sensing and information processing, decision support, manufacturing strategy and reconfigurable building blocks."

The Cambridge IKC will combine research in sensor and data management with innovative manufacturing processes to provide radical changes to the construction and management of infrastructure. The aim is to transform the industry through a whole-life approach to achieving sustainability in construction and infrastructure, covering design and commissioning, the construction process, exploitation and use, and eventual decommissioning. The IKC will complement the Laing O'Rourke Centre for Construction Engineering and Technology at Cambridge, a new multi-disciplinary academic centre of excellence to advance the engineering profession and leverage innovative thinking to benefit the construction industry.

Talking about the new centres, EPSRC's Chief Executive, Professor David Delpy, said: "Taking exciting research from the university laboratory to the commercial sector through close collaboration with user stakeholders is vital to ensuring the UK's economy continues to be innovative and globally competitive. EPSRC is strongly committed to supporting universities in commercialising their outstanding research and I applaud the innovative approach taken by the successful applicants, and all competing universities."

The Technology Strategy Board's Chief Executive, Iain Gray, said: "These two new Innovation and Knowledge Centres are highly important for the UK and economic growth because they harness specialist academic knowledge and business expertise in areas where we have proved capabilities and we know that we can do well. By pooling know-how, capability, and expertise in one centre, the UK maximises the opportunity to innovate effectively and generate economic growth."

The Cambridge IKC on Smart Infrastructure and Construction will be led by Professor Robert Mair and Professor Kenichi Soga of the Civil Engineering Division of the Department of Engineering. Professor Duncan McFarlane of the Department's Institute of Manufacturing (IfM) will also play a leading role. Dr Paul Heffernan of the IfM will be the full-time IKC Director. The IKC will bring together four leading research groups in the Cambridge Engineering Department and the Computer Laboratory, along with staff in the Judge Business School and the Department of Architecture.

Innovation and Knowledge Centres (IKCs) are centres of excellence with five years' funding to accelerate and promote business exploitation of an emerging research and technology field. Their key feature is a shared space and entrepreneurial environment, in which researchers, potential customers and skilled professionals from both academia and business can work side-by-side to scope applications, business models and routes to market.

Funding for the Cambridge IKC will be £10million from EPSRC and the Technology Strategy Board, with an additional £7million from a number of industry organisations.

Cambridge academics named among most important figures in British science

Professor Dame Ann Dowling

The Times newspaper has named 12 Cambridge academics in their inaugural list of the 100 most important contemporary figures in British science. The first ranking of contemporary figures in British science was released today in Eureka, The Times’ monthly science magazine.

Professor Dame Ann Dowling Head of Engineering is included in the list. As the UK lead for the recent 'Silent Aircraft' initiative, Ann aimed to develop a conceptual design for an aircraft whose noise would be almost imperceptible outside the perimeter of a daytime urban airport. She is a Fellow of Sidney Sussex College.

Also from the Department of Engineering is Professor Mark Welland Director of The Nanoscience Centre. His research encompasses a number of aspects of nanotechnology ranging from sensors for medical applications to understanding and controlling the properties of nanoscale structures and devices. He is also Chief Scientific Adviser at the Ministry of Defence.

The list includes the following Cambridge academics from other Departments:

Stephen Hawking is the Director of Research at the Department of Applied Mathematics and Theoretical Physics, Emeritus Lucasian Professor of Mathematics at the University as well as a Fellow of Gonville and Caius College. Hawking is best known for his pioneering research into black holes, thermodynamics and unifying Einstein's general relativity theory with quantum theory, as well as his book A Brief History of Time.

Sir Richard Friend, Cavendish Professor of Physics and Fellow of St John's College, has revolutionised our understanding of carbon-based semiconductors. His research helps to develop flat panel displays, and flexible screens that can be rolled up and transported.

David Mackay is Professor of Natural Philosophy at the Cavendish. He is the creator of Dasher, a machine-learning system that allows users to navigate using any muscular movement, their breath or gaze, and write using a continually unfurling alphabetical display. He is also currently Chief Scientific Advisor at the Department of Energy and Climate Change.

Sir David Baulcombe holds the Regius Professorship of Botany at the University of Cambridge. Sir David discovered how small molecules of ribonucleic acid (RNA) govern gene activity through a process known as RNA silencing. Professor Baulcombe's research has unravelled how this mechanism is important in gene regulation and in disease resistance. He is a Fellow of Trinity College.

Sir Greg Winter is a Fellow of Trinity College and Deputy Director of the MRC's Centre for Protein Engineering. He is known for his pioneering work on therapeutic monoclonal antibodies.

Professor Sir Leszek Borysiewicz is the new Vice-Chancellor of the University of Cambridge. He was Chief Executive of the UK's Medical Research Council from 2007 to last month, and from 2001 to 2007 was at Imperial College London, where he served as Principal of the Faculty of Medicine and later as Deputy Rector.

Professor Steve Ley is BP Professor of Organic Chemistry at the Department of Chemistry and a Fellow of Trinity College. His research focuses on developing new synthesis methods and applying them to the construction of biologically important molecules.

George Efstathiou is Professor of Astrophysics and Director of the Kavli Institute of Cosmology. Professor Efstathiou and his team provided some of the first evidence that dark energy exists. He is a Fellow of King's College.

Steve O'Rahilly is Professor of Clinical Biochemistry and Medicine and Co-Director of the Institute of Metabolic Science. His research focuses on the links between genetics and obesity.

Shankar Balasubramanian, Herchel Smith Professor of Medicinal Chemistry at the Department of Chemistry, developed (along with Professor David Klenerman) low-cost, high throughput sequencing that enables researchers to undertake large-scale projects. In 1998 they founded the spin-out company Solexa (which was later purchased by Illumina) to commercialise their inventions.

Exploratory Study of Organisational Creativity in Creative Organisations


Dr James Moultrie's paper 'Exploratory Study of Organisational Creativity in Creative Organisations', published in Creativity and Innovation Management Journal last year, has been awarded the Tudor Rickards Award for the best paper published in the journal during 2009, as voted for by the editorial panel. The research was originally conducted by one of James' MPhil students as part of his dissertation project on the MPhil in Industrial Systems, Manufacture and Management course. It was later submitted to the 2008 Creativity and Innovation Management community workshop in Buffalo where it was selected for publication in the journal.

Many researchers have aimed to understand what it is that makes an organisation creative. The results of these studies indicate that organisations adopt a number of strategies to enhance their creativity. Research suggests that there are nearly 30 of these strategies, including; making time for creativity, providing staff with freedom from bureaucracy, providing an open and trusting culture, and encouraging playfulness. But, this research has been conducted mostly in firms where creativity is not necessarily central to the success of the organisation.

In contrast, this study sought to explore whether the same strategies apply in firms which are inherently creative. A simple assessment tool was developed, based on the outputs of previous research, and used to explore the creative climate in firms that by their very nature are creative: design agencies. The study specifically sought to compare two dominant models used to explain organisational creativity.

The results suggest that the existing models used to understand creativity are independently effective, but when combined provide a more effective set of strategies. Some of the strategies are less relevant in creative firms, including the availability of materials to enhance creativity (e.g. model making materials), training (to enable creativity), structured management systems and the avoidance of conflict. This represents an important contribution, suggesting that there is no ‘one size fits all’ set of strategies, but that they need to be tailored to the specific context. In addition, the assessment tool developed for this research provides a practical contribution, to enable organisations to easily and simply assess their creative climate.


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