Christmas Conference Poster Competition Winners
2012 Winning Posters
The 2012 competition was open to Graduate School members, with separate categories for research students and contract research staff
GaSb Quantum dot solar cells with extended photoresponse (Winner - PhD Category)
Juanita James - Physics
The generation of renewable energy is one the most important challenges facing society today and development of high efficiency, cost-effective solar cells are an important part of the solution.
This project explores GaAs solar cells containing GaSb quantum dots, and investigates the benefits of these photonic nanostructures for efficiency enhancement in concentrator solar cells which are deployed in desert locations.
Nailing jelly to a wall: How I learned to love allometric scaling (Runner-up - PhD Category)
Matthew Barnes - Lancaster Environment Centre
Allometry literally means "of other or different measure". One of the first allometric studies examined the metabolic rate of mammals plotted against their mass on a log-log scale. This relation is sub-linear and occurs across 27 orders of magnitude from an amoeba to a whale.
Recent studies have focused on cities, for example, a city of 8 million people will have more than double the number of patents as a city of 4 million people. My research establishes scaling laws in UK cities with respect to air quality, and determines sustainability parameters. As the population of a city increases the total pollutant emissions do not increase as much as would be expected (sub-linear relation), but as the area of a city increases, emissions increase more than expected (super-linear relation). These relations change when only larger cities are examined enabling potential sustainable solutions to be created. The area of a city should be greater than 26 square km, the population greater than 35,000 inhabitants, with total nitrogen oxide emissions less than 363 tonnes per year. These boundaries determine that approximately 60 cities within the UK could be classified as sustainable from an air quality perspective.
2011 Winning Posters
The 2011 competition was open to Graduate School members, with separate categories for research students and contract research staff
Creating the Next Generation of Telecoms Lasers (Winner - PhD Category)
Kylie O'Shea - Physics
Lasers are used in telecoms to transmit signals through optical fibres. The optical fibres allow optimum transmission at two wavelengths, 1.55 μm and 1.3 μm. As the lasers get hot during operation, they should ideally operate at temperatures up to 85 oC, so that they can be produced and run cheaply.
The lasers currently used are very successful at achieving the correct wavelengths, but they only operate at lower than ideal temperatures, requiring them to be cooled which consumes 90% of the power applied to the device.
My research looks specifically at creating (lower cost) GaAs-based lasers that emit at 1.55 μm. By growing GaInAsNSb quantum wells between GaAs barrier layers, I aim to tune the emission wavelength to 1.55 μm, whilst maintaining the material quality of current lasers and extending the operating temperature.
Encouraging results have been found from the initial material samples. Emission in one sample reached 1.55 μm, and, in another, emission was achieved up to and beyond 85 oC. By adjusting the composition I believe both should be possible in a single material sample in the near future. This opens up the next stage of research; using the material to fabricate and test a proto-type laser.
Acknowledgements: This work is supported by EPSRC and Oclaro Inc.
Time for Natural Remediation in the Hyporheic Zone? (Runner-up - PhD Category)
Marina Dudley-Southern - Lancaster Environment Centre
Integrated catchment management is required under the Water Framework Directive. Interfaces between water bodies are highlighted as areas where significant biogeochemical cycling can be expected to occur. Low nitrate concentrations are evidenced within the surface water to groundwater interface; the hyporheic zone, as a result of biogeochemical cycling. From a management perspective, the consequences of future nitrate-contaminated groundwaters discharging into surface waters are uncertain, but attenuation of polluted waters within the hyporheic zone may help to reduce the ecological impact on receiving waters.
Studying the hyporheic zone is inherently complicated: not only is the zone likely to be highly heterogeneous (physically and biogeochemically) but there are multiple sources of water crossing the interface and each flowpath within the zone. Each flowpath may exhibit a different residence time, which will influence the type and extent of reactions that can occur along that flowpath. It is proposed here that stable and radioisotopes in water can aid the characterisation of pathways within the hyporheic zone and quantify residence times.
To address this problem, water samples are being collected from an instrumented reach of the River Leith, Cumbria, UK and analysed for the composition of stable isotopes in the water molecule and for radon-222. Being located in the Eden Special Area of Conservation restricts the use of injected tracers and supports the use of evaluating hyporheic flowpaths using natural isotopic tracers. The 400m gaining reach is populated with piezometers, both in the riverbed and the surrounding riparian zone. Lateral, longitudinal and vertical variations in pore water chemistry are being assessed by extracting pore water samples from multi-level samplers installed alongside the piezometers.
The reach includes a pool-riffle-pool (PRP) sequence. In a PRP sequence, stream water is expected to infiltrate into the streambed at the head of the riffle and return back to the stream at the tail of the riffle. Stable isotope and radon-222 data will be used to test this conceptual model and will inform a simple groundwater mixing model. Preliminary results indicate that downwelling at the head of the riffle is evident in both stable and radioisotope data. A number of new piezometers with multi-level samplers have been installed along the PRP sequence and these will be sampled periodically to determine the location, depth and residence time of hyporheic flowpaths beneath a PRP sequence.
This work will provide a field-based assessment of hyporheic flow processes, through the combined use of natural isotopic tracers, and will contribute to a greater understanding of the complexities of the hyporheic zone.
Modelling water flow and transport in real soils and catchments (Winner - CRS Category)
Jessica Davies - Lancaster Environment Centre
Understanding the volume, timing, and pathways of water flow in catchments is central to predicting stream-flow, water quality and availability, and the transport of pollutants and nutrients - all of which have important implications for society and the environment.
Subsurface flows form a major component of run-off generation, but predicting water movement in soils is complex. They contain many structural features such as worm burrows, plant root channels, fissures and soil pipes that allow water to move much more rapidly than in the surrounding pores. In addition, heterogeneities continue to larger scales, with catchments containing multiple soil types and substrates that have differing hydraulic properties. These important features are rarely represented in hydrological models. Most models assume that soils are homogenous and that the water in the soils is well mixed.
The Multiple Interacting Pathways project is developing a novel model that directly represents flow and transport through the complex pathways in the soil. It uses random particle tracking to simulate movement of water through the subsurface. The particles travel with a distribution of velocities that represent the range of pathways available to the water, and probabilities are defined that allow particles to move from one pathway to another. As water chemistry, age and origin can be associated with each particle, this realisation opens up numerous possibilities for exploring chemical transport, water sources and catchment residence times.
The poster presents modelling results of artificial tracer and isotope experiments carried out in a test catchment in Sweden, and laboratory scale experiments being conducted at Lancaster Environment Centre.
2010 Winning Posters
The 2010 competition was open to Graduate School members, with separate categories for research students and contract research staff
How does the heart affect brain activity - a modelling approach? (Winner - PhD Category)
Tom Hansard - Physics
Do brain models need to be so complicated?
With modern computers it is easy to include many details in a brain model, but are they needed?
We try to avoid this pitfall by basing our model upon the most fundamental aspect of neuronal dynamics.
Locking Out the Evil Guys... Without Using Keys (Runner-up - PhD Category)
Tony Chung - Computing and Communications
The use of wireless networks is increasing despite the risk of attack. Traditional access control precautions are based on keys and cryptography.
This approach is problematic:
- Keys can be stolen or hacked.
- Cryptography costs energy.
- Denial of service can target the cryptography itself and waste energy.
Distance-Based Message Authentication, or DBMA, uses physical boundaries and the laws of physics to lock out attackers without using keys.
Quantum Dot Solar Cells (Winner - CRS Category)
Peter Carrington - Physics
The development of efficient affordable photovoltaic (PV) solar cells for clean energy production is a major global challenge. On a clear day, solar energy of approximately one kilowatt per square meter reaches the Earth's surface. A single hour of solar energy reaching the Earth would be enough to supply the world's energy needs for an entire year. Photovoltaic (PV) production has been increasing by an average of more than 20% each year since 2002, making it the world's fastest-growing energy technology. The major challenges in the development of solar cells is to decrease the cost and increase the efficiency.
2009 Winning Posters
The 2009 competition was open to GradSchool members, with separate categories for research students and contract research staff
Geomagnetically Induced Currents in the National Grid (Winner - PhD Category)
Katie Turnbull - Communication Systems
The dynamic interaction of the Earth's magnetosphere with the Sun produces geomagnetic storms. These are the cause of the Aurora but can also be hazardous by damaging technologies heavily relied upon in modern life. In particular power transmission networks are susceptible to Geomagnetically Induced Currents (GIC) which can potentially cause the entire network to fail.
By producing a model of the National Grid that calculates GIC production in the grid we hope to determine the risk posed to the UK by geomagnetic storms.
A new technique for the accurate imaging of shielded radiation sources (Runner-up - PhD Category)
Jamie Adams - Engineering
Characterising buried radiological contamination is a problem facing the nuclear industry on a global scale, these decommissioning challenges include:
- Contaminated land
- Sealed and buried containers
- Storage ponds
- Hazardous or dangerous structures
An estimated 20 million cubic metres of radiologically contaminated land is believed to be present at the Sellafield site alone.
A fast, portable and accurate system for the preliminary assay of contaminated land and facilities would prove useful for the decommissioning industry. It would assist in reducing costs, hazards to staff and project timescales.
The Differential Effect of Interview-Interviewee Culture on Nonverbal Correlates of Deception (Winner - CRS Category)
Ruth Miles - Psychology
Cross-cultural misunderstandings can lead to inappropriate suspicion and even prosecution in police scenarios where behaviour is observed and evaluated (e.g., interview).
Research has identified many cultural differences in nonverbal behaviour, some of which materialise in deception and truth-telling.
However, to date, research on nonverbal correlates of deceit has been anecdotal or qualitative, and distinctly mono-cultural.
Here we use newly-developed automatic measures to examine the nonverbal behaviour of respondents who provide genuine and fabricated accounts in a cross-cultural interview.
2008 Winning Posters
The 2008 competition was open to GradSchool members, with separate categories for research students and contract research staff
How does 'lumpiness' in the very early universe show up in observations? (Winner - PhD Category)
Rose Lerner - Physics
We consider the effect of a brief space-dependent step in the energy driving inflation.
Inflation occurred soon after the 'big bang' and can be though of as an exponential expansion of space-time. Tiny quantum fluctuations in the otherwise almost completely smooth universe grow during inflation and provide the seeds for structure such as galaxies and galaxy clusters in the universe today.
We find that the effect of the lumpiness is to produce 'resonances' in the spectrum of seed perturbations on scales equal to the scale of the lumps.
The effect is negligible if the lumps are of a small size. However, 'lumpiness' during inflation could provide a mechanism to explain subtle effects, such as non-Gaussianity, recently found in data.
Judging Stylistic Distance With Authorship Ratios (Runner-up - PhD Category)
Edward Bell - Computing
Stylometrics summarise aspects of an author's latent stylistic profile. This research presents a method of formulating an empirical authorship distance measure via a linear combination of both non-parametric and parametric stylometrics.
The most well regarded stylometrics, and the ones used here, summarise lexical facets of language (vocabulary). The distance measure is estimated with a genetic algorithm and then validated on 248 works of 18th century fiction (40 million words).
The Dependence of Frequency and Field on Stochastic Ordering in Photonic Band Gap Resonant Structures (Winner - CRS Category)
Carolyn Matthews - Physics
In recent years the application of 2-Dimensional (2D) metallic Photonic Crystal (PC) structures to high power microwave devices, such as particle accelerators and gyrotrons, has gained increased interest. The work presented here focuses on the effect disorder has on the resonant frequency and peak electric field in the defect site of a 2D PC structure.
For disorders up to a maximum of 15% variation in position and radius, we found that disorder applied to the inner-most scatterers surrounding the defect site dominates in determining the peak field and resonant frequency of the structure. We also show that small disorder (~1%) can lead to an increase in peak field in certain cases.
We find increasing levels of disorder lead to a decreasing average peak field for all structures, whereas the mean resonant frequency remains constant for increasing disorder while the standard deviation increases.
We then develop an understanding for this behaviour in terms of frequency detuning and mode confinement.
2007 Winning Posters
The 2007 competition was open to faculty research students
The Importance of Relaxin During Pregnancy (Winner)
Abigail Thompson - Medicine
Implantation failure is a major cause of sterility, presenting a social and economic burden worldwide. Rates of sterility continue to increase and are only partly controlled by assisted reproductive technologies; which have low success rates. Determining the mediators of implantation however is hindered by ethical concerns of studying the process in vivo in humans and the difficulty to duplicate exactly the specialized uterine environment and the implanting embryo in vitro.
Relaxin, known as the pregnancy hormone for decades, plays a distinct role in pregnancy in rats and pigs. Primarily expressed in the third trimester of these animals, it is responsible for widening of the birth canal and softening of the cervix. However, in human women relaxin is expressed at greater levels during the first trimester and may therefore be involved in softening of the uterine tissue at the implantation site.
A method recently developed to study implantation will be employed during this project to determine the localisation of the relaxin protein at the implantation site and its potential role in mediating this. The method includes development of confrontation cultures, comprising 8-12 week decidua parietalis from elected abortions and a trophoblast/choriocarcinoma hybrid cell line as a model system for implantation. Antibodies developed against relaxin will then be used in Immunocytochemistry studies at different time points, including early attachment phases of the cell line to the decidua and deeper invasion stages.
This project aims to produce information that can be used for improving fertility rates.
Listening for Cancer (Runner-up)
Adam Bradbury - Physics
A number of low frequency oscillations are readily detectable in human physiological measurements. This project is concerned with investigating the effect certain cancers may have on the nature of these oscillations and their relationships to one another.
Nutrient limitation at the alpine treeline (Runner-up)
Will Mallott - Biological Sciences
Tree growth and associated ecosystem processes decline in high elevation forest leading to the formation of the alpine treeline.
We examined patterns of nutrient limitation across elevational gradients in montane forest in the European and New Zealand Alps.
Our findings indicate that nutrient limitation may influence treeline elevation through a series of feedback effects between above and below-ground communities. In addition we show that the temperature sensitivity of treeline systems may be buffered by nutrient limitation of below-ground community activity despite predicted rises in global temperature.
2006 Winning Posters
The 2006 competition was open to faculty research students
Infrared Microspectroscopy: Potential Applications In Cervical Cancer Screening (Winner)
Michael Walsh - Biological Sciences
The introduction of cervical cancer screening has led to dramatic reductions in the incidence and mortality from this disease. However, this screening programme remains flawed due to inadequacies in sensitivity and specificity.
Infrared (IR) microspectroscopy has the potential to deliver an objective and automated approach by which biomarkers of abnormality are identified.
In this study, multivariate analysis of IR spectra was found to segregate normal, low-grade, high-grade and invasive carcinoma exfoliative cervical cytology.
Standardising Spelling in Early Modern English Texts (Runner-up)
Alistair Baron - Computing
The computer-aided analysis and processing of natural language text is a well established area of research. Tools have been developed for many language processing tasks including semantic analysis, part of speech tagging and spell checking, these have mainly focused upon modern texts. One major problem in using these tools with older English texts is the lack of consistent spelling between different texts and even within the same text.
The aim of my research is to produce a tool which can facilitate the analysis and readability of English historical corpora by standardising spelling variants found within. The tool must be easy to use with as little human input as possible. The tool must also be very precise when replacing spelling variants. Due to the large scale of the domain there are many avenues of research to explore. The main focus of the research will be to develop new techniques and improve upon existing methods to increase the precision of spelling variant replacement. There are also other lines of research away from the precision of the tool; these include integrating the software with other corpus analysis tools, as well as using the software with other historical language variations.
Micrometeorological measurements from the Telecom Tower - London (Runner-up)
Ben Langford - Environmental Science
Emissions of anthropogenic volatile organic compounds (VOC) from the urban environment are currently highly uncertain. Although national atmospheric emission inventories exist for this group of compounds, they fail to provide a spatial breakdown of the individual compounds (Nemitz, 2006). These uncertainties are in part due to a lack of suitable analytical instrumentation. Although some VOC can be measured by gas chromatography, some oxygenated compounds cannot. Also, the slow response times of the GC make it unsuitable for micrometeorological measurements such as eddy covariance.
The advent of the Proton Transfer Reaction – Mass Spectrometer (PTR-MS), an online VOC analyser, has addressed these issues, enabling micrometeorological techniques such as eddy covariance to be used to measure VOC fluxes from area sources.
2005 Winning Posters
The 2005 competition was open to all faculty staff
Paleoenvironmental reconstructions on the Cerro Blanco subcomplex of Nevados de Chillán volcano, using volcanic facies (Winner)
Jennie S. Gilbert, Katy Mee and Hugh Tuffen
Nevados de Chillán volcano, central Chile (Fig. 1) has been active for at least 640 ka(1) and continues to be active at the present day. Eruptions have occurred during both glacial and intergalcial periods, with frequent interaction between volcanic products and snow and ice of varying thicknesses.
Field evidence and volcanic textures from three andesitic lavas from the Cerro Blanco subcomplex of Nevados de Chillán are used here to aid reconstructions of former eruptive environments.
Supportive or suggestive? Using drawings to help children talk about touch (Runner-up)
Deirdre Brown (Lancaster University, UK), Michael Lamb (Cambridge University, UK), Margaret-Ellen Pipe (NICHD, USA), Yael Orbach (NICHD, USA), Charlie Lewis (Lancaster University, UK)
In cases of child abuse children are often the only witness or source of evidence, but what they tell investigators is often insufficient to secure a conviction or acquittal.
Researchers have therefore explored techniques that can support children to tell as much as possible about what they have seen or experienced, without compromising the accuracy of the information they report.
Identifying and evaluating these techniques is important to ensure that children are adequately protected from their abusers, but also to ensure that innocent defendants are not wrongfully convicted.
Nanostructures for Optoelectronic Devices Grown using Molecular Beam Epitaxy (Runner-up)
M.Stone, Q.Zhuang, A.Godenir, R.Jones, A.Krier
Molecular-Beam Epitaxy (MBE) is an ultra-high vacuum technique for the production of high quality semiconductor nanostructures. The special merit of this technique is that epitaxial layers can be grown with thickness control at the single monolayer level and precise control over alloy composition and doping levels.
Our research involves using MBE in the quantum engineering of novel semiconductor nanostructures with optimized electrical and optical properties for the development of next generation LEDs, lasers and photodetectors operating in the mid-infrared (2-5 µm) spectral range.