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QinetiQ Ltd

17 Projects, page 1 of 4
  • Funder: UKRI Project Code: EP/G062609/1
    Funder Contribution: 353,817 GBP

    There are many different types of microphones: their primary function is transduction: converting pressure waves (within some range of frequencies) into a single electrical signal, usually as precisely as possible. After this, the signal may be used for recording or for interpretation (which is our interest here). A major problem in interpretation is that the signal may have a large amount of energy in some parts of the auditory spectrum, but much less in others, and that this distribution may alter rapidly. Often, it is the energy in these lower energy areas that is critical for interpretation. Current practice is to filter the single electrical signal from the microphone (whether using FFTs, or bandpass filters), then examine the signal so produced. We propose a different approach in which the pressure wave is directly transduced into multiple electrical signals, corresponding to different parts of the audible spectrum. By making the transducers active (i.e. providing them with a rapidly adjusting gain control), we will be able to increase the sensitivity of the filters in those areas where additional sensitivity can be useful in the interpretation task, and reduce the sensitivity in those areas where the signal is very strong. The auditory interpretation tasks undertaken by animals (solving the what and where tasks when there are - as is normally the case - multiple sound sources in a reverberant environment) is the same task that an autonomous robot's auditory system needs to undertake. Animal hearing systems include multiple transducers, and provide numerous outputs for different parts of the spectrum, whilst adjusting their sensitivity and selectivity dynamically. Current microphones provide a single electrical output, which is then either processed into a number of bandpass streams (maintaining precise timing), or into a sequence of FFT-based vectors, such as cepstral coefficients (losing timing precision). The proposed active MEMS microphone performs the spectral breakdown at transduction, providing an inherently parallel output whilst maintaining precise timing. Further, it is adaptive. This adaptive capability, non-existent in current microphones is important in hearing aids. Precise timing information is important for source direction identification using inter-aural time and level differences. Where there are multiple active sources, accurate foreground source interpretation requires some degree of sound streaming, requiring the ability to examine features of the sound, often in spectral areas which with relatively low energy.The active MEMS bandpassing microphone will consist of a membrane which will vibrate due to the external pressure wave. The membrane is physically linked to different resonant elements (bars) in the MEMS structure - these elements will have a range of resonant frequencies. Further, these bars will act as gates for MOS transistors, resulting in their vibration modulating the current passing through these transistors. The modulated current will be coded as a set of sequences of spikes, and these spikes processed to provide a signal to adjust the sensitivity of each of the resonators by using an electrostatic effect to change the response of the transistors to the vibration of the bars. The modulation will be used to adjust the gain so that quiet areas of the spectrum are selectively amplified and loud areas of the spectrum selectively attenuated. In this way, it will be possible to build an integrated MEMS/CMOS microphone which can attenuate loud areas of the spectrum concurrently with amplifying quiet areas of the spectrum. The spike coded output will be made available in a way compatible with the address-event representation (AER), making it compatible with existing and proposed neuromorphic chips form other laboratories.

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  • Funder: UKRI Project Code: EP/G063710/1
    Funder Contribution: 868,884 GBP

    There are many different types of microphones: their primary function is transduction: converting pressure waves (within some range of frequencies) into a single electrical signal, usually as precisely as possible. After this, the signal may be used for recording or for interpretation (which is our interest here). A major problem in interpretation is that the signal may have a large amount of energy in some parts of the auditory spectrum, but much less in others, and that this distribution may alter rapidly. Often, it is the energy in these lower energy areas that is critical for interpretation. Current practice is to filter the single electrical signal from the microphone (whether using FFTs, or bandpass filters), then examine the signal so produced. We propose a different approach in which the pressure wave is directly transduced into multiple electrical signals, corresponding to different parts of the audible spectrum. By making the transducers active (i.e. providing them with a rapidly adjusting gain control), we will be able to increase the sensitivity of the filters in those areas where additional sensitivity can be useful in the interpretation task, and reduce the sensitivity in those areas where the signal is very strong. The auditory interpretation tasks undertaken by animals (solving the what and where tasks when there are - as is normally the case - multiple sound sources in a reverberant environment) is the same task that an autonomous robot's auditory system needs to undertake. Animal hearing systems include multiple transducers, and provide numerous outputs for different parts of the spectrum, whilst adjusting their sensitivity and selectivity dynamically. Current microphones provide a single electrical output, which is then either processed into a number of bandpass streams (maintaining precise timing), or into a sequence of FFT-based vectors, such as cepstral coefficients (losing timing precision). The proposed active MEMS microphone performs the spectral breakdown at transduction, providing an inherently parallel output whilst maintaining precise timing. Further, it is adaptive. This adaptive capability, non-existent in current microphones is important in hearing aids. Precise timing information is important for source direction identification using inter-aural time and level differences. Where there are multiple active sources, accurate foreground source interpretation requires some degree of sound streaming, requiring the ability to examine features of the sound, often in spectral areas which with relatively low energy.The active MEMS bandpassing microphone will consist of a membrane which will vibrate due to the external pressure wave. The membrane is physically linked to different resonant elements (bars) in the MEMS structure - these elements will have a range of resonant frequencies. Further, these bars will act as gates for MOS transistors, resulting in their vibration modulating the current passing through these transistors. The modulated current will be coded as a set of sequences of spikes, and these spikes processed to provide a signal to adjust the sensitivity of each of the resonators by using an electrostatic effect to change the response of the transistors to the vibration of the bars. The modulation will be used to adjust the gain so that quiet areas of the spectrum are selectively amplified and loud areas of the spectrum selectively attenuated. In this way, it will be possible to build an integrated MEMS/CMOS microphone which can attenuate loud areas of the spectrum concurrently with amplifying quiet areas of the spectrum. The spike coded output will be made available in a way compatible with the address-event representation (AER), making it compatible with existing and proposed neuromorphic chips form other laboratories.

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  • Funder: UKRI Project Code: NE/J020753/1
    Funder Contribution: 535,275 GBP

    Global climate prediction models need accurate information on the amount of greenhouse gases (methane CH4 and carbon dioxide CO2) hosted by seafloor sediments as free gas and gas hydrates. Extensive distributions of seafloor methane gas and methane gas hydrate have been detected by geophysical surveys on continental margins around the world, while monitoring of carbon dioxide seepage from sub-seafloor CO2 reservoirs will become increasingly important as full scale carbon capture and storage facilities come online in future. However, quantification of the amount of in situ gas using geophysical remote sensing methods remains a challenge. In this technology-led proposal, we intend to provide the required step change in knowledge that will allow us to relate seafloor geophysical measurements to gas content and thus provide the marine community with the necessary survey know-how. The main barrier to progress is our poor state of knowledge of the effect of gas and gas hydrate morphology (i.e., size and shape) on the measured geophysical sediment properties acoustic velocity and attenuation, and electrical resistivity. Gas bubbles in sediments are known to show complex shapes and size distributions that are strongly influenced by sediment type. Muddy sediments show crack-like gas bubbles while sandy sediments show spheroidal gas bubbles. If these sediments occur in deep enough water on the continental slope, then methane gas hydrate may form producing equivalent crack-like or disseminated hydrate morphologies. Only dedicated, well controlled laboratory experiments can hope to unravel the complex interaction between gas and hydrate morphology, sediment type and the observed geophysical properties. Unfortunately, no such experimental capability exists at present, so we will have to develop our own laboratory measurement system. Our solution is to build the world's first acoustic pulse tube for gas- and gas hydrate-bearing sediment studies. It will enable the bulk acoustic and electrical properties of large sediment core samples, up to 1 m long, containing natural methane (or carbon dioxide) gas bubbles or hydrate, to be measured under simulated seafloor pressures and temperatures. Experiments on synthetic muds with known amounts of methane and hydrate will also assist our understanding of these physical property inter-relationships. We will also study relevant theoretical models that will be tested against the laboratory experimental results. These validated models are what we need to interpret seafloor geophysical measurements in terms of in situ gas and hydrate content. We will interact with other scientists seeking to quantify seafloor greenhouse gas associated with methane hydrates in the Arctic and sub-seafloor carbon dioxide storage sites, and with potential industry and government end-users of seafloor geophysical technologies.

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  • Funder: UKRI Project Code: EP/H001972/1
    Funder Contribution: 365,792 GBP

    Single walled carbon nanotubes are proving themselves to be remarkable candidates for disruptive nanoelectronic devices. Electrons can flow through them ballistically, which means that they travel without being scattered by features in the material of the nanotube. It is possible to make transistors with single walled nanotubes with both electron and hole conductors, thus providing components for complete logic circuits. It is even possible to make transistors which work with a change of only a single electron in the active region. All of this could be very significant for future electronics applications, but that would be only the beginning, because these devices use only the charge on the electron. There is another secret weapon which can be used, in the form of the electron spin.The electron spin can be thought of as a tiny magnet, which can point in one of two directions (often referred to as up and down). The new field of electronics which this opens up already has a name, spintronics, and its own Nobel Prize Winners. The biggest current application of spintronics is in the heads for reading data on hard discs in computers, revolutionizing this multibillion dollar industry. Magnetic random access memory is now being made and sold, with the promise of ever higher access speeds. The search is on for new materials systems which can be used for spintronic devices, which may in turn be exploited in new applications. New effects are being discovered all the time. For example, if you apply different temperatures to the two ends of a metallic magnet, a current of electron spins can flow.Our vision is to put spin into carbon nanoelectronics. If we can do this, we may be able to add a whole new capability to what is already possible with nanotube transistors. For this purpose we shall use other carbon materials, even smaller than nanotubes, in the form of cages called fullerene molecules (also known as Bucky balls). These molecules can each contain one or more atoms which carry a resulting electron spin. They can be inserted into single walled nanotubes, and the resulting structures are sometimes called peapods, because that is what they look like in an electron microscope. Peapods provide an ideal way to put spin into nanotubes.In our research programme, we shall fabricate peapod transistors, and look at them by high resolution transmission electron microscopy under conditions which minimise the damage to the samples. In this way we shall be able to see with atomic resolution the very piece of material which is active in the device. We shall measure the current through the transistor while we vary the magnetic field and the temperature, and look for effects which may be very sensitive to one or other of these. We shall apply microwave radiation, and detect the effect on electrical conductance as we sweep the magnetic field through the spin resonance. Finally we shall perform controlled experiments to measure electrically the direction of the spin.Although these are fundamental experiments, our hope is that they will lead to practical applications. These may be through the effects of collective excitations, for applications such as nanoelectronic circuits and sensors, or they may be through direct control of the spin states, for more revolutionary devices such as quantum logic devices, quantum memories and perhaps even eventually quantum computing.

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  • Funder: UKRI Project Code: EP/H000240/1
    Funder Contribution: 288,262 GBP

    The global semiconductor market has a value of around $1trillion, over 90% of which is silicon based. In many senses silicon has driven the growth in the world economy for the last 40 years and has had an unparalleled cultural impact. Given the current level of commitment to silicon fabrication and its integration with other systems in terms of intellectual investment and foundry cost this is unlikely to change for the foreseeable future. Silicon is used in almost all electronic circuitry. However, there is one area of electronics that, at the moment, silicon cannnot be used to fill; that is in the emission of light. Silicon cannot normally emit light, but nearly all telecommunications and internet data transfer is currently done using light transmitted down fibre optics. So in everyones home signals are encoded by silicon and transmitted down wires to a station where other (expensive) components combine these signals and send light down fibres. If cheap silicon light emitters were available, the fibre optics could be brought into everyones homes and the data rate into and out of our homes would increase enormously. Also the connection between chips on circuit boards and even within chips could be performed using light instead of electricity. The applicants intend to form a consortium in the UK and to collaborate with international research groups to make silicon emit light using tiny clumps of silicon, called nanocrystals;. These nanocrystals can emit light in the visible and can be made to emit in the infrared by adding erbium atoms to them. A number of techniques available in Manchester, London and Guildford will be applied to such silicon chips to understand the light emission and to try to make silicon chips that emit light when electricity is passed through them. This will create a versatile silicon optical platform with applications in telecommunications, solar energy and secure communications. This technology would be commercialised by the applicants using a high tech start-up commpany.

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