School of Applied Sciences (SAS) (2006-July 2014)

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Browsing School of Applied Sciences (SAS) (2006-July 2014) by Course name "MSc by Research"

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    Conductivity grading in epoxy graphene oxide composites using thermal reduction.
    (Cranfield University, 2014-02) Chatzi, Panagiota; Skordos, Alexandros A.
    The aim of this project is the development of a method for the production of conductivity graded polymeric materials through the in-situ reduction of Graphene Oxide (GO). These types of composites can be used for the reduction of electrical field concentrations observed in several applications, such as cables, cable joints, microelectronic components and bushings. The evolution of electrical conductivity of GO was monitored during thermal reduction under isothermal and dynamic heating thermal conditions and compared with the kinetics of the reduction reaction as observed using calorimetry. These results were replicated in epoxy/GO composite to prove the feasibility of in-situ reduction and capabilities for controlling this process. In addition, reduction was achieved in epoxy/GO composites using infrared continuous and pulsed laser. It was shown that thermal reduction is possible in the cured epoxy composite at relatively low temperatures up to 26ᴼC. The kinetics of reduction follows a double mechanism which can be represented using a double n-th order process. Electrical measurements showed that conductivity increased significantly up to 0.12 S/m for dry particles and 0.09 S/m for the composite. Heat transfer by conduction and irradiation on specific areas resulted in selective reduction, and a conductive graded material.
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    Filtration efficiency following polymer addition
    (2007) Fabrizi, Lara; Jarvis, Peter; Jefferson, Bruce
    Natural organic matter has become an increasing concern in drinking water treatment, because of the potentially carcinogenic disinfection by-products that form when disinfectants react with the residual organic carbon not removed by the treatment process. Organic and inorganic matter at water treatment works (WTW s) is usually removed by aggregating the matter into large insoluble aggregates, known as floes, and then separating the floes from the water: Synthetic organic polymers are widely used to improve the characteristics of floes. These polymeric additions enhance natural organic matter removal in the subsequent separation phase. The efficiency of the reaction between polymer and floes is dependant on several factors such as the properties of the polymer and the particular site conditions. The choice of on-site polymer dosing is not simple because of the complex interactions between polymers and particulates, the influence of water quality and. operating conditions. Polymer dosing in drinking water treatment does not follow a general rule and is usually based on trial and error or industrial experience. This thesis details the work conducted to provid~ diagnostic support to existing onsite investigation on the optimum polymer dose and conditions required for the treatment of natural organic matter rich waters at Albert WTWs, Yorkshire, UK. Seasonal variations in water quality were investigated both at the iaboratory scale and full-scale. The effect of polymer dosing on floe filterability was studied on water samples collected at Albert WTWs using a jar tester and two particle sizing instruments based on laser diffraction. Outlet turbidity and headloss were monitored during laboratory sand filtration experiments. The results of the on-site data analysis showed great variability in the effect of site conditions on sand filtration performance. Polymer dosing as a filter aid improved particle removal by sand filtration during winter, that resulted in lower filtered turbidity and ultraviolet light at 254 nm wavelength. The results of laboratory experiments demonstrated that polymer dosing increased floe size and re-growth and marginally improved floe strength, particularly for waters at low dissolved organic carbon content. Temperature had no significant impact on floe size or strength. The bench scale filter trials showed that there was an increase in the filter headloss with increasing polymer dose. Outlet turbidity was higher when no polymer was dosed and this was explained by performing particle count analysis on the inlet and the outlet of the bench sand filter. The results showed that when no polymer was dosed the filtrate contained a higher number of particles than when polymer was dosed. The number of particles in the inlet water decreased proportionally .to the amount of polymer dosed, particularly after floe growth. Polymer dosing has the effect of mopping up small particles and so makes them easier to filter. Polymer dosing engineers floe characteristics for improved filtration by reducing the concentration of particles onto the sand filters. The optimum dose of synthetic polyacrylamide on water after dissolved air flotation at Albert water treatment works is between 0.01 and 0.02 mg/L: such a dose ensures long filter runs and low outlet turbidity.
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    Information and communication technology (ICT) in the early years of education
    (2008) Abdalla, Eman Shafik Hassan; Lemon, Mark
    Information and communication technology (ICT) has become an important factor in the education field, especially for pupils with special educational needs. The aim of this research is to understand how ICT is perceived to affect the learning capability of primary age pupils, including those with special educational needs. The specific objectives are to: (i) Investigate the literature about the relationship between information and communication technology (ICT) and pupils with special educational needs; (ii) Identify some of the factors that affect the use of information and communication technology (ICT) for assisting pupils’ learning (reading and writing) ability in three case studies school; (iii) Investigate the current use of ICT resources in three schools and the roles played by teachers and parents in these schools to help pupils learn in both classroom and home environments; (iv) Assess the perceived impact of ICT on pupils’ learning through observation and interviews in the case study schools; (v) Communicate examples of best practice, for both teachers and parents, on more effective way of using ICT to improve pupils’ learning. The research has been carried out in three schools one of which is a special school for pupils with special educational needs. Data have been collected in three ways. Firstly, direct observation has been carried out in the classroom; secondly, interviews have been carried out with teachers; and finally a survey of 175 parents was carried out by questionnaire. The key finding drawn from this research indicate that ICT is perceived to have a positive impact on pupils’ learning regardless of their educational needs. The study also identified that ICT is perceived to improve the quality of teaching and ICT use by primary age children. A second issue raised the shortage of teacher training for ICT, especially staff development, and finally, teachers and parents needed time to become skilled with the new technologies before attempting to teach with them. The study presents examples of best practice to distinguish between how teachers and parents might improve their support for pupils using ICT. These include the need for teachers to match learning needs, style and curricula and for parents to understand how their pupils learn and the nature of any learning problem.
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    Maximising struvite recovery from real wastewater sources
    (2007-04) Thomas, David J. L.; Parsons, Simon
    Formation of struvite (MgNFLjPCU.ôFfeO) in reactors is proposed to limit struvite problems in sewage treatment works (STW) and offer a method of phosphorus recovery and recycling. Four sites of interest were identified by Severn Trent Water Ltd: Derby, Wanlip, Stoke Bardolph STW and Coleshill sludge destruction plant for their potential to produce struvite. Initial tests on sludge liquors collected from the four sites showed that >80% of initial orthophosphate could be removed when the Mg:PC>4 ratios was adjusted to >2:1 for Wanlip, Stoke Bardolph STW and Coleshill at pH 9. Two reactor types, a fluidised bed reactor (FBR) and a stirred tank reactor, were trialled in Phase 1 testing with Wanlip STW liquors. The FBR was able to achieve a >90% orthophosphate removal with Mg additions of 3.5 to 5 mmol but produced a suspended solid content of -300 mg L"1. To overcome the problem of ‘fines’ a metallic mesh accumulation device was fitted to the reactor. The mesh system was able to reduce the suspended solids within the liquors <50mg L' 1 when the reaction time was increased from two to three hours. The stirred tank reactor was able to remove on average 55% of the phosphate content of the liquors with a magnesium addition of 5mmol. In Phase 2 testing both types of reactor were run side-by-side in a continuous operation. In the three experiments carried out the initial orthophosphate concentration was adjusted to 95 mg L' 1 (Immol). The stirred tank reactor was able to consistently remove -65% of the influent orthophosphate concentration in the 3 experiments at a Mg:P0 4 ratio of 3.5:1. The FBR removal steadily improved from 25% to 65% over the 3 experiments. The metallic mesh system was further trialled here and successfully captured 4.1 g of struvite. A cationic polymer, polyDADMAC, was also tested for the capture of fines with less success than in previous reports. The precipitate from each reactor was analysed with SEM-EDS and XRD. The FBR produced relatively pure struvite and stirred tank a struvite and amorphous material mixture.
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    Process parameter sensing for remote hyperbaric welding
    (2009-08) Papadopoulos, Konstantinos; Yapp, D.
    Pipeline ovality and equipment set-up variations pose a challenge for offshore remote hyperbaric welding operations using a fillet welded sleeve for pipeline repair. The distance from the torch to the pipe should be kept as constant as possible to maintain optimum welding process stability. The work of this research project was focused on using through-the-wire sensing and the establishment of the feasibility of Dip Resistance measurement as a suitable method for real time contact tip to work-piece distance estimation and control under Hyperbaric Welding conditions. Analysis of cases of Dip Resistance application in 1 Atm and factors of influence has been performed and their relevance and importance for the RPRS program is examined. Suitability of the Dip Resistance is concluded and verification of this under hyperbaric conditions is tested. For this purpose, a data acquisition hardware system was built and software was written using Lab VIEW 7.1 in order to acquire and analyse the welding signals in real-time and store the signals for later analysis. A second program focused on the analysis of the Dip Resistance information was written using Lab VIEW 7.1 in order to analyse the experimental data off-line and to evaluate the results in more detail. Experiments were made using various welding patterns so as to determine the feasibility of the method of the use of Dip Resistance information as a method for real-time estimation and control of the weld process. Based on these results, three detection algorithms were evaluated and the most suitable one was selected for further investigation. Initial investigation on other factors of influence like the length of the welding current’s path and resistance variation with temperature is examined. The results from the experiments and their off-line analysis are presented and a discussion of the results is presented. It is concluded that real-time control of the contact tip to work-piece distance torch may be achieved in real-time using dip resistance monitoring if it used in conjunction with the welding current and welding voltage signals allows achievement of robust control. Suggestions for further study and achievement of a complete solution are presented.