MSc & MSc Funded Theses

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Open Access
Investigation into the manipulation of the properties of Indium Tin Oxide (ITO) coatings
(Cranfield University, 2008) Atterbury, Clair; Nicholls, J. R.; Hatchett, Phil
This thesis investigates the manipulation of the properties of Indium Tin Oxide (ITO) coatings. This is carried out with a combination of Experimental and Theoretical work. The coating of ITO onto a glass substrate was both theoretically modelled and the practical work analysed to observe the effects. Observation of the effects on the output parameters when depositing a single layer of ITO via Electron beam evaporation onto a glass substrate multiple times with varying conditions was carried out. The amount of ITO required to produce optimum % transmission and the deposition conditions required to provide <20 7/▢ and <100 7/▢ were investigated. This study then considered the addition of a single layer of an additional coating both theoretically and practically to maximise the %T for the wavelength ranges under consideration. From this, the ideal refractive index for the additional coating to maximise the %T for the ranges was deduced. Progression was then made to consider multiple layers. Theoretical work carried out on the addition of extra layers and the deduction of the optimal refractive index implied that overall, Cryolite would produce the best average %T across the ranges considered. In addition to this, the results of ITO deposition via Evaporation and sputtering were examined to determine the difference the technique used has upon the coating produced.
Open Access
Low temperature ITO thin film deposition for solar cells
(Cranfield University, 2008-09) Seraffon, Maud; Impey, Susan A.; Lawson, K. J.; Rao, Jeff
The electrical and optical properties as well as the microstructure of indium tin oxide thin films deposited on glass and flexible substrates is demonstrated in this project report. This project is a part of an MSc in Advanced Materials at Cranfield University. The understanding and improvement of indium tin oxide coatings deposited by magnetron sputtering on both glass and polymer substrates has been an area of extensive research in the last decade. This technology appears to be very interesting in terms of money saving and efficiency in the solar cell domains where the coatings are used in thin film solar cells. Research into the thin film solar cells mechanism, the sputtering process and ITO coatings is reported, along with detailed consideration of the best results obtained in the past in terms of ITO films’ electrical and optical properties. ITO thin films were deposited on glass and different sputtering parameters were changed in order to investigate their influence on the coatings properties: film thickness, chamber pressure, rotation, oxygen amount and sputtering power. A decision was made to establish the best sputtering parameters. These parameters were set to deposit ITO on polyethylene terephthalate (flexible substrate). The samples were also annealed at 150°C and 370°C. An ITO thin film with a resistivity of 1x10-4 Ωcm and a 90% transmissivity was obtained. An Energy Dispersive Spectrometry analysis was finally made on samples showing a substoichiometric composition of the ITO films.
Open Access
A pilot study into the use of fossil fuels in golf course maintenance operations under Swedish conditions
(Cranfield University, 2008-09) Caple, Matthew; Dufour, Michael; Blombäck, K
A method is proposed for measuring fuel consumption of golf course maintenance machinery within this study, in response to growing industry concerns to rising fuel prices and greenhouse gas emissions. The aim of this method is for its implementation as a maintenance optimisation tool to allow measurement, prediction and ultimate reduction in fuel consumption in maintenance. Volumetric fuel consumption was recorded for various operations by refilling fuel tanks back to the same levels prior to operations being performed. Results were presented initially in the primary unit of fuel consumption per cycle. A cycle was identified as the work required to perform an operation on a particular feature type, and which did not change in its nature between cycles. This in-situ method allowed fuel consumption measurements to be replicated for the same maintenance operations. Four secondary units to portray fuel consumption were created, one being area mown per litre of fuel, which allowed fuel consumption to be normalised by area and compared across golf courses. Key maintenance cycles were assessed on three different golf courses in Sweden. From the data collected, it was determined that rough mowing typically consumed the greatest amount of fuel per cycle and fairway mowing the greatest amount per year. Fairway mowing was also found to be the most fuel efficient operation. On the main test site, 86% of yearly diesel consumption was accounted for by operations that could be categorised into cycles. The proposed method was determined to be feasible for extended use due to its simplicity and ease of repetition. Normalisation of the data allows for further research to be undertaken into identifying inefficient operations and seeking methods to reduce fuel consumption. Further research should be undertaken over a whole golfing season to determine the accuracy for mean fuel consumption per cycle and to enable sporadic and smaller operations to be measured on an individual basis. The affect that distance travelled by machines between features has on cycle fuel consumption is the main recommendation for further adaptation of the method.
Open Access
Phylogenetic analysis black box
(Cranfield University, 2008-09) Naval Sanchez, M; Huxely-Jones, J.; Larcombe, Lee D
Open Access
The restoration of an urban still water fishery: monitoring for success at Tom Thumb Lake
(Cranfield University, 2008-09) Hughes, Stephen; Gill, Andrew B.
Tom Thumb Lake is a former gravel pit and carp fishery situated in East London. In 2005 the Lake was restored as an accessible, self-sustaining fishery. The objectives of this study were to outline a monitoring plan to assess the success of the restoration, this included: monitoring water quality in relation to the requirements of fish, monitoring the macroinvertebrate communities in areas of the lake that will be newly vegetated, an angler survey to assess basic demographics (such as age, sex, ethnicity) and whether or not the priority groups identified by the Environment Agency were using the Lake. In addition, a basic topographic survey was conducted. Basic water quality parameters (temperature, pH, DO, N and P) were monitored at Impact sites (those to be vegetated) and Reference sites (an area of the Lake already well vegetated), macroinvertebrate samples were also taken at these locations. The water quality requirements of fish were based on Incipient Lethal Levels (ILL) taken from fish physiology publications. The survey was completed and handed out to anglers but numbers returned were not sufficient for inclusion in this report. The topographic survey identified a depth range of 0-2.4m, with shallow areas predominantly close to known gravel bars in the centre of the lake. Based on the monitoring data collected, water quality was generally well within the limits researched from literature, although temperature and pH were occasionally close to the upper limits. Macroinvertebrate samples showed some differences, particularly in total abundance, between the Impact and Reference sites. An outline set of monitoring guidelines were constructed for future managers of the Lake to follow, which should enable them to reliably gauge the success of the project. Recommendations for refining the ILL method and potential uses for other lakes were made.
Open Access
An investigation into whether a BTCC racing car can be shown to emit no more carbon dioxide than its showroom equivalent
(Cranfield University, 2008-09) Hannington, Lee; Blackburn, Kim
The British Touring Car Championship’s emissions initiative aims to demonstrate a BTCC racing car can emit no more CO2than its showroom equivalent, (the standard road car that racing cars are based upon) for publicity purposes. This research project investigates options, which might achieve this aim, although this may not be possible. A series of initial concepts were considered and rejected. A drive-cycle option was investigated. Well-known, existing drive-cycles were considered unsuitable in the present context as unlikely to provide the desired results. In-race operating conditions data for a typical BTCC racing car was collected and analysed for drive-cycle development. Further data was collected on the specifications and performance of a BTCC racing car and its showroom equivalent. The cars’ CO2 emissions were subsequently estimated. Statistical analysis was carried out on the in-race operating conditions data. The BTCC race data commonly included operating conditions beyond the limitations of the BTCC’s dynamometer and the racing cars showroom equivalent. Under wide-open throttle operation at steady engine speeds between 5500rpm and 6000rpm, the mass of CO2emitted per second, by a BTCC racing car, is predicted to be less than that emitted by its showroom equivalent under the same conditions. However, since these engine speeds are infrequently reached during BTCC races such a comparison could be open to criticism through focussing on unrepresentative data. Further, such an emissions ‘window’, may not apply to all BTCC racing cars and their respective showroom equivalents. At corresponding points across a range of race representative engine speeds (5500-8500rpm for the racing car and 3500-6000rpm for the showroom equivalent), under wide-open throttle operation, steady engine speed emissions tests are predicted to show the BTCC racing car emitting a similar or lesser mass of CO2per kWh than its showroom equivalent. This last comparison is the recommended solution.
Open Access
The summer nutrient dynamics of Bosherston lakes, Pembrokeshire, and the potential impacts of future climate and policy change
(Cranfield University, 2008-09) Niciecki, Georgina; Holman, Ian P.
Bosherston Lakes, Pembrokeshire have had problems with high nutrient concentrations and algal blooms, particularly in the stream-fed Eastern Arm, leading to the loss of Chara within the Eastern Arm. Management in the last 25 years has led to a reduction in external nutrient loading, but the impact of internal loading during the summer has yet to be properly assessed. The potential impacts of climate and policy change on the nutrient dynamics need to be accounted for to be able to efficiently manage the site in the future to preserve the important Chara habitat. The streams and lake water were analysed for both Total Reactive Phosphorus (TRP) and Total Phosphorus (TP) and Nitrate and Total Nitrogen. The sediment in the lakes were analysed for TRP and TP only. Phosphorus release from sediments and the impact of future temperature changes were assessed through laboratory experiments. It was found that the lakes are still suffering from elevated nutrient levels during the summer. The main source of phosphorus to the lakes in the summer is probably through internal phosphorus release from the lake sediments. The Eastern Arm is the most affected by internal loading. The main sources of nitrates to the lakes are from the streams and groundwater. It was found that phosphorus release increased with increasing temperature. There are many uncertainties but future climate changes are likely to increase both nutrient and sediment loading and it is unlikely that the water quality in the Eastern Arm will improve sufficiently to accommodate Chara. The introduction of an NVZ is unlikely to be counterproductive in terms of reducing N:P ratios and will help decrease nitrate levels in the lakes and streams, some of which are nearing the safe drinking water limits. Future management should target phosphorus loaded sediment entering the lakes in the winter and contributing to the phosphorus concentration in the lake water during the summer when phosphorus is released. The sediment traps in the catchment should be maintained or enhanced and weed cutting should be continued if it is found to have no adverse ecological effects.
Open Access
Impact of NOM on flocs created in the drinking water process
(Cranfield University, 2008-09) Cairns, Peter Ryland; Jefferson, Bruce
Increased regulatory pressure to meet THM standards with the possible introduction of HAA regulations means that organic matter, the predominant DBP precursor needs to be removed effectively from site whilst coping with increased economic and environmental drivers for change. Organics are typically removed via coagulation / flocculation which can be optimised by operating in the correct zeta potential range (-10mV and +8mV) and the correct DOC:FE coagulant dose ratio (1:1). However, due to spatial and temporal changes in bulk NOM and its fractional character there are no standard operating conditions, consequently sites have to respond to changing conditions. Seasonal trends in DOC and THMFP levels were measured under optimised and current operational conditions. Results indicated that UV254 could be used to predict coagulant dose and zeta potential could be used to indicate optimum coagulation conditions for DBP precursor removal across 16 sites. Under optimised condition improved organics removal and floc properties was observed across all source waters however the degree to which this occurred depended on the source water. Understanding of the fractional make up is thus important to assess the potential for optimisation of the coagulation process. Providing the electrostatic forces are minimised, increasing the NOM content of the floc matrix will lead to an increase in floc strength. One of the implication of optimised coagulation conditions were that flocs could be created at lower retention time then quoted by best practice guidelines. As such a 66% decrease in flocculation energy could be achieved without any detrimental impact to floc quality or removal efficiency. One of the important findings is that due to the inherent difference in source waters, optimisation for a site can vary in terms of cost and clarified water quality, hence each site needs to be evaluated before schemes are carried out.
Open Access
An investigation into illegal discharge of sewage from boats in the broads
(Cranfield University, 2008-09) Hardwick, Susannah; Holman, Ian P.
In response to concerns expressed by the Environment Agency and Broads Authority, this project aimed to assess the risk of illegal sewage discharge from boats into the waterways of the Broads, East Anglia. The Broads are an internationally important wetland, consisting of marshes, fenland, rivers and shallow lakes. A popular area for boating, sewage discharge from boats could have deleterious impacts on the environment, health and public perception. Water was tested for evidence of faecal pollution at a mooring site at Thorpe Island, River Yare, identified as at risk from illegal sewage disposal from boats. Continuous monitoring of ammonia, ammonium and dissolved oxygen up and downstream of the moorings took place at half hourly intervals over six weeks. Thermotolerant coliforms, ammonia, phosphorous and dissolved oxygen were manually sampled at Thorpe Island and nearby Whitlingham sewage treatment works. Definitive evidence of pollution from boats was not found, either sewage was not illegally discharged during the study period, or methods were inadequate to identify the occurrence of faecal pollution with certainty. The distribution of sewage disposal facilities available for boats was also analysed. The navigable waterways of the Broads were categorised in terms of the risk of illegal sewage disposal due to distance from disposal facilities. The south eastern reaches of the River Bure and western reaches of the River Waveney were identified as being at most risk. Recommendations are made to identify areas of the Broads at risk from pollution due to factors other than distance from sewage disposal facilities. Any further water quality studies should be carried out in these areas and improvements to the methods are suggested. Future management should include raising awareness of boaters about issues surrounding sewage disposal and the consideration of the provision of either mobile or static sewage disposal facilities in areas where current provision is deemed inadequate.
Open Access
An evaluation of the restoration programme for a cut over section of Wedholme Flow raised mire
(Cranfield University, 2008-09) Lewis, Graham; Howden, Nicholas J. K.
Wedholme Flow, Cumbria is the site of the largest lowland raised mire remaining in the UK. It forms part of a group of ombrotrophic mires known as the Solway mosses, situated in the north west of England. As with all remaining raised mires in the UK, Wedholme Flow has suffered some historical degradation largely caused by cutting of peat at the site’s periphery for fuel. More recently large sections of the mire surface have been commercially mined mainly for horticultural use. These include sections which have been cut over by hand leaving baulks or upstanding strips of unmolested peat between cuttings but also sections of the mire surface that have been strip mined or milled using machinery. Because of the complete loss of Sphagnum the sections of the mire surface that have been milled represent a particular challenge in terms of restoration. The reinstatement of the Sphagnum layer or acrotelm typical of raised mire sites is an important restoration objective. In order for Sphagnum to re-colonise a cut over mire site the water table must remain in close proximity to the surface of the peat throughout the year. The absence of an acrotelm however contributes to seasonal water table fluctuation by decreasing surface storage and allowing increased evaporation from the surface .On cutover mire sites primary restoration efforts centre on raising the water table sufficiently to facilitate Sphagnum re-colonisation and growth with a view to restoring a functioning acrotelm. This study provides a critical appraisal of a restoration programme that aims to raise water levels on a cutover section of Wedholme Flow in Cumbria. The restoration programme was undertaken by Natural England who own and manage the site. Since acquiring the cut-over section of the site bunds and peat plugs have been installed to reduce drainage and raise the water table. Boreholes have been installed on site to monitor changes in water level during and after the restoration. The progress of the restoration programme is evaluated through examination of the water balance, available groundwater data and a review of contemporary literature. Recommendations for further restoration and monitoring are made.
Open Access
Waste management within a public organisation
(Cranfield University, 2008-09) Dlamini, Delly; Drew, Gillian H.
Through air pollution from landfill, the increase in waste generation poses a local and global threat to the environment. The UK government recognises organisations’ contribution to meeting raised targets for waste recycling. This research therefore, shows that organisational waste, associated with office operations is produced in large quantities and hence, very significant in contributing towards meeting national recycling targets. The paper addresses two key areas in managing organisational office waste for sustainable development within a public organisation. First, office waste recycling logistics were examined and secondly, the link between sustainable waste management practices such as recycling and the dissemination of information to participants about waste schemes and their ultimate success was investigated. Waste policies and implementation strategies were found to be the determinants of waste management program’s effectiveness. Organisational policy and strategy were identified as drivers in mainstreaming effective waste management within an organisation, especially participation in recycling schemes and waste minimisation. Simultaneously, recycling levels and levels of waste awareness within an office showed a positive relationship. The results show that continuous waste awareness promotions are key to translating high awareness levels into action among recycling participants in the organisation. Overall, an expected reduction in waste destined for landfill was reciprocated by an increase in material collected for recycling. The implications for organisational policy making to ensure staff sustainable waste management behaviour in organisations are also explored.
Open Access
Evaluating the potential of anaerobic waste stabilisation ponds for wastewater treatment in a temperate climate
(Cranfield University, 2009) Ansari, Ilyas A.; Jefferson, Bruce
A pilot scale baffled anaerobic waste stabilisation pond (aWSP) was designed based on an organic loading of 0.17 kg COD m-3 d-1 to evaluate the potential of aWSP as a passive, sustainable technology for domestic wastewater treatment in temperate conditions. After 4 weeks of operation and up to 45 days (end of study), average removals of 37% COD, 30% BOD and 36% suspended solids were observed which compares to the literature surveyed for aWSP treating domestic wastewater. A linear correlation between COD removal and time since start-up was observed and compared favourably to an anaerobic membrane bioreactor (aMBR) that was started up unseeded. Seeding the aWSP apparently augmented start-up and whilst higher COD removal for aWSP have been reported, it is anticipated that continued operation (>45 days) will yield further efficiency improvements. Methane reported in the gas and liquid phase was approximately 4.1% and 5.7 mg l-1 respectively suggesting relatively low production of methane. However, this does demonstrate that methanogenesis occurred soon after start up. Using this data to model a 5000 PE site, total energy output of 62 MWhy-1 (electricity and heat) was generated and only 6 MWh y-1 (electricity) consumed, this compares to an equivalent conventional activated sludge process (ASP) which uses approximately 655 MWh y-1 electricity for aeration. Results to date suggest that aWSP technology represents a viable sustainable alternative for domestic wastewater treatment in a temperate climate versus traditional high energy technologies.
Open Access
House buyer perceptions on the value of water and grey water recycling systems
(Cranfield University, 2009-08) Horton, David; Jeffery, Paul
The population of the East of England is set to increase and climate change predictions suggest that the region will become drier; water resources will therefore come under increasing pressure. In order to meet future water demand and deliver a reliable supply in the years to come, Cambridge Water is assessing the feasibility of installing grey water recycling systems in future housing developments. Grey water is wastewater from showers, baths, and wash basins. Recycling this water is an innovative way to conserve water. Treated grey water is used principally for toilet flushing- which represents about a third of water use in a typical UK household- but also for watering gardens and washing cars. This study investigated house buyer perceptions on the value of water and grey water recycling systems. For this purpose 2000 customers were surveyed using a questionnaire. The aim was to inform Cambridge Water as a water supplier of how receptive their customers would be to receiving a secondary supply of treated grey water for non-potable use. All those sampled had moved into a newly built home in the past two years. Since investing in grey water recycling systems would have little or no financial benefit for the homeowner, the study focused on other potential benefits. The response rate for the survey was 22 per cent and the quantitative data was analysed using descriptive statistics. The results show that there was widespread support for the domestic use of grey water. The overwhelming majority of respondents would be willing to invest in grey water recycling systems because they are concerned about the environment, and to ensure a reliable supply at times of water scarcity. Many of those that objected stated that they would need further information before giving their consent.
Open Access
Desalination technologies for developing countries: what solutions?
(Cranfield University, 2009-09) Groult, Lucille; Tyrrel, Sean
Desalination is a water treatment option known by people at large for its large scale use in rich countries such as in the Middle East. Nevertheless, this is not an option for some developing countries such as Kenya, as, due to the water scarcity existing in such places, saline water is the only source for drinking purposes. Numerous technologies exist for desalinating water, from the very simple process of solar desalination already in use in the antiquity, to the most complicated membrane or electronic technologies. Appropriate solutions adapted to development or emergency situations have to be taken depending on the context in place in developing countries. Through discussions with private companies and research laboratories, some of the most up to date systems currently usable have been reviewed in order to assess their suitability for an implementation by the charity Oxfam GB in a near future in several locations in West African and South Asian countries. Criteria have been defined according to the needs observed by the charity in targeted places, better targeting possible appropriate technologies. The study focused on technological details as well as long term management issues for optimising ownership of the local communities. After comparison of the reviewed technologies and confrontation with the defined criteria, it resulted that interesting options available for development are membrane-based or distillation. The use of clean energy sources such as brute strength (mechanical systems using animal or human strength) simplify operation and maintenance, and lower operation cost at the same time for a sustainable implementation in remote villages. Automated electronic-based systems are also an opportunity for emergency situations. However, most of those solutions have not been in use in a developing country yet. Consequently, innovative experimentation is needed for the good of all.
Open Access
Drinking water quality and treatment practices in Pabal, India
(Cranfield University, 2009-09) Mukadam, Aisha; Webster, James
The drought prone, rural village of Pabal is an example of improved access to water through a piped water system, however at times the villagers are also recipients of a poor water quality supply. Prevailing illnesses of diarrhoea and gastro-intestinal diseases, especially during the monsoons result in 40-50 % of villager‟s income being spent on medical bills. This research project provided by Engineers Without Borders – UK and EngINdia aims to form an investigative study into the current water quality and treatment methods in Pabal. This was achieved by analysing water samples using the DelAgua Water Testing Kit for microbial pathogens (faecal origins) at different points in their distribution system as well as carrying out a social survey through 22 questionnaires and a few target interviews. Results showed the reservoir water source to be highly contaminated but chlorination at the storage tank removed all traces of thermotolerant faecal coliforms. However all consumer points were also found to be contaminated as well as at the borehole hand-pump. Qualitative data collected through observations, sanitary surveys and the questionnaires provided possible reasons for contamination. The pipeline is in disrepair through lack of maintenance, pollutants and effluence (human and animal) are leached into groundwater and pipe supplies, as there are also no drainage or refuse systems in the village. Most villagers are aware and practice basic health, sanitation and water treatment however some only treat once they fall ill. Water treatment is essential in Pabal at all times and should be implemented at a cost-effective household level. The villager‟s health may be safe guarded by utilising traditional methods such as cloth filtering, copper pot storage (anti-bacterial properties) in addition to chlorination. Further education and future water treatment designs based on biosand and UV filtering can be produced locally via the community involving educational centre Vigyan Ashram.
Open Access
Semantic based approach for knowledge management
(Cranfield University, 2009-09) Sanya, Isaac; Shehab, Essam; Roy, Rajkumar
Companies are beginning to understand the importance of the management and maintenance of knowledge resources. One of the main constraints that have hindered the solution to resolving technical problems has been the efficient access to knowledge and expertise. Currently, the problem of ‘understanding’ has been one of the main limitations that have hindered the robustness of conventional systems due to lack of ‘semantics’ in knowledge representation. Therefore, there is need for enhancing the management and maintenance of knowledge through a semantic based approach. Semantics is defined as the study of meaning in communication and it aims to identify relationships between syntactical elements through the use of ontologies. The aim of this thesis is to develop prototype tools utilising semantic based approach for knowledge management in order to demonstrate and quantify the potential capability of these technologies within the defence equipment support market. The development of these semantic based prototypes are based upon accomplishing certain objectives: (i) transform an existing Excel based cost model into a semantic based application (ii) capture complex knowledge about maintenance and diagnosis of equipments in one central knowledge base, (iii) incorporate within the prototype a two way dialogue to help in diagnosing a problem and allow for rapid discovery of appropriate solutions, (iv) evaluate and validate use of semantic based approach to manage knowledge within the defence equipment support market, (v) use of multiple cases to demonstrate the benefits of semantic technology. The aim and objectives of this research project was achieved by adopting a qualitative research approach and a fivephase research programme methodology. The research project has highlighted that the use of semantic technology enhances the reusability, flexibility and maintainability of knowledge and its management. The ability to represent functionalities graphically reinforces understanding and makes functionality editing easier. Semantic technology can also be deployed gradually which means it can mature with the problem. The definition of synonyms and ontologies gives semantic technology an advantage over other computer based knowledge representation techniques. This research project successfully demonstrates and quantifies the benefits of semantic technology.
Open Access
Beyond narrative: modelling metaphor in environmental discourse
(Cranfield University, 2009-09) Naughton, Linda; Cook, Matthew
This project aims to bring together ideas from a wide range of disciplines with the objective of exploring the use of metaphor in environmental discourses. It looks beyond the narrative form of story-lines to construct models of discourses by representing processes as spatial arrangements of content. The subject to be explored is the competing discourses of economic growth and sustainability, an area which continues to generate much debate but little change in economic policy. The current dichotomy of views representing the pursuit of growth as somewhere between essential to social stability and the root of all evil has prevented a move towards consensus in the debate. This study aims to explore the ways in which an analysis of metaphor within the discourse could open up possible conduits towards the goals of sustainability.
Open Access
The water balance of Lake Victoria: towards an accessible and updateable model
(Cranfield University, 2009-09) Murray-Williams, Róisín; Carter, Richard C.
Lake Victoria is the world’s second largest fresh water lake and with a basin spanning five countries the livelihoods of 30 million people depend upon its waters. Many water balance studies have been carried out yet there are often great difficulties in accurate data collection. This study aims to provide an accessible and easily updateable tool for modelling the water balance of Lake Victoria using publically available data. The study also investigates possible future lake level behaviour and the impact that water level fluctuations has on key stakeholders in the basin. In this study lake levels are successfully modelled from 1948-present using rainfall data available publically from the WMO and the NOAA using an equation modified from one developed by Nicholson et al, 2000. This therefore provides a tool which is accessible and updateable. Modelled lake levels underestimated some of the peaks in the observed record, however the correlation between observed and modelled levels was good, R2 = 0.8. As a departure around 2007/8 was observed, the performance of the NOAA data needs to be monitored over the coming years. Modelled future lake level behaviour varied considerably. The data from one GCM resulted in a significant increase in lake levels from 2010-2099 whereas the other two showed a slight decline on present levels. A challenge is posed by a high occurrence of inter-model disparities in East Africa. Whether a rise or decline is to be expected there are many stakeholders who will be affected in particular; water supply, fishing and hydro-electric generation directly and industry indirectly through power supply. Although there are a number of limitations of the model, this study provides a useful step in assessing the water level behaviour of a lake which is so important to the region.
Open Access
Assessment of an innovative soil aerator on soil physical disturbance and reducing runoff on compacted grassland
(Cranfield University, 2009-09) Shanahan, Peter; Simmons, Robert W.; Hann, Michael J.
Poor grassland management practices increases compaction and reduces infiltration leading to increasing risk of poaching and runoff generation. On-site impacts of grassland compaction include the loss of topsoil structure which also reduces soil ecosystem functioning. In addition, ongoing diffuse water pollution from compacted grassland limits the ability of the UK’s authorities to meet EU water quality guidelines such as the Water Framework Directive and address flood risks in areas of extensive grassland management (e.g. Boscastle, 2004). This study investigates the effects of an innovative ground-driven rotary soil aerator at alleviating soil compaction and reducing overland flow (designed by Mr. Roger Clay, Herefordshire). The magnitude of soil disturbance from slotting was assessed at the Cranfield University Soil Dynamics Test Centre soil-bin. Draught and vertical force requirements and tillage efficiency were also determined for varying depth and horizontal and vertical angle combinations using an Extended Octagonal-Ring Transducer (EORT). The effect of various slotting treatments on runoff was then investigated on a steep compacted permanent pasture in Herefordshire using erosion plots and simulated rainfall. From the soil-bin assessment, soil disturbance was most efficient (lowest specific draught) at 100 mm depth, a vertical angle of 18° and with increasing horizontal angle (0° to 10°). The draught requirement for a single bladed disc at 18° vertical ranged from 0.88 to 1.24 kN (90-126 kg force) and a maximum vertical force or ballast requirement of 257 kg force per bladed disc. Slotting treatments reduced runoff by 75% as compared with the non-slotted control.
Open Access
Determining the carbon footprint of a National Trust country estate
(Cranfield University, 2009-09) Slater, Dora; Burgess, Paul J.; Williams, Adrian
The UK Government aims to reduce greenhouse gas emissions by 80 % by 2050 against a 1990 baseline. Agriculture makes up around 7 % of UK emissions and the industry is under pressure to meet these targets (and to produce more food). To achieve reductions it is necessary to be able to calculate emissions. This study looks at methods to calculate the carbon footprint of a National Trust estate with livestock, arable farming and a stately home. Methods explored include greenhouse gas inventories, life cycle analysis and carbon calculators. A carbon calculator designed for farms was selected (the CALM Calculator) and applied to Wimpole Hall, Cambridgeshire. Key greenhouse gas sources were identified and estate activity data gathered to calculate the footprint. A comparison was made between current arable practices and proposed organic methods. Emissions from estate energy and water consumption were also included. The arable non-organic farm emitted 1018 tCO2e, 73 % due to N2O emissions from nitrogen fertilizers. The livestock farm emitted 686 tCO2e, 44 % from cattle. Estate emissions from electricity, heating oil and water supply were 303 tCO2e. The total estate footprint was calculated as 2007 tCO2e. A change to organic arable methods was predicted to deliver an estate footprint of 1361 tCO2e but yields will be less (organic wheat is said to yield only 68 % of non-organic). The removal potential of conversion of areas of arable to grassland (41 tCO2e) and particularly of farm woodland (1430 tCO2e) was noticeable. Combined these can offset 73 % of total estate emissions using non-organic arable methods and 103 % of total estate emissions using proposed organic arable methods. Shortcomings of the method are identified along with the high level of uncertainty connected to the results. The issue of reduced yield expected under organic arable cultivation is highlighted and the implications of balancing reduced emissions with maintaining food production are explored.