Recent Submissions

  • Behaviour of continuous concrete T-beams reinforced with hybrid FRP/Steel bars

    Ashour, Ashraf A.; Sheehan, Therese; Almahmood, Hanady A. A. (University of BradfordFaculty of Engineering & Informatics, 2020)
    This work aims to investigate the flexural behaviour of continuous hybrid reinforced concrete T-beams (HRCT). The investigations consist of three parts; the computational part, the experimental part and the finite element analysis. The computational part included two parts, the first one is developing an analytical programme using MATLAB software to investigate the moment-curvature behaviour of HRCT-beams and to design the experimental specimens. This was followed by the experimental part, where six full-scale reinforced concrete continuous T beams were prepared and tested. One beam was reinforced with glass fibre reinforced polymer (GFRP) bars while the other five beams were reinforced with a different combination of GFRP and steel bars. The ratio of GFRP to steel reinforcement at both mid-span and middle-support sections was the main parameter investigated. The results showed that adding steel reinforcement to GFRP reinforced concrete T-beams improves the axial stiffness, ductility and serviceability in terms of crack width and deflection control. However, the moment redistribution at failure was limited because of the early yielding of steel reinforcement at the beam section that did not reach its moment capacity and could still carry more loads due to the presence of FRP reinforcement. The second part of the computational part included the comparison between the experimental results with the ultimate moment prediction of ACI 440.2R-17, and with the existing theoretical equations for moment capacity, load capacity, and deflection prediction. It was found that the ACI 440.2R-17 design code equations reasonably estimated the moment capacity of both mid-span and middle-support sections and consequently predicted the load capacity of the HRCT-beams based on fully ductile behaviour. However, Qu's and Safan's equations underestimated the predicted moment and load-capacity of HRCT-beams. Also, Bischoff's and Yoon's models underestimated the deflection at all stages of the load for both GFRP and HRCT- beams. For the numerical part, a three-dimensional finite element model has been developed using ABAQUS software to examine the behaviour of HRCT-beams. The experimental results were used to validate the accuracy of the FEM, where an acceptable agreement between the simulated and experimental results was observed. Accordingly, the model was used to predict the structural behaviour of continuous HRCT-beams by testing different parameters.
  • Blockchain Technology for Data Sharing in the Banking Sector

    Awan, Irfan U.; Norvill, Robert E. (University of BradfordDepartment of Computer Science, Faculty of Engineering and Informatics, 2020)
    Know Your Customer compliance costs have never been higher for banks in Europe. This thesis looks at the application of blockchain technology to reduce Know Your Customer compliance costs. The work within aims to utilise the strengths of blockchain technology in order to reduce the costs of compliance for banks. This is done through collaboration with industry partners, resulting in a system designed to meet banks’ needs. The contributions of this work are: 1) A system which enables data sharing between banks, enabling 2) reduc tion of costs by at least 45%, and 3) reducing or eliminating over reliance on third parties, 4) an exploration of how to price data within the system is made in order to help banks further reduce their costs, 5) reduction of chain size by reducing the size of contract creation transactions in Ethereum by 90% for standard users, lastly, 6) to better understand the functionality and purpose of smart contracts. The system is the first of its kind to remove the requirement of third party storage solutions, and is the first to explore pricing aspects in detail.
  • Chieftaincy reform, decentralisation and post-conflict state reconstruction and peacebuilding in Sierra Leone 2004-2012

    Cooper, Neil; Pankhurst, Donna T.; Kormoh, Joseph L. (University of BradfordPeace Studies and International Development, Faculty of Management, Law and Social Science, 2020)
    Liberal peacebuilding, the means by which transition societies can be reconfigured and reconstructed to bring about lasting peace, focussed on chieftaincy reform and decentralization as part of the peacebuilding package in Sierra Leone. The main focus of this research is to explore the efficacy of these structures as durable peacebuilding mechanisms in a transition society like Sierra Leone. The core argument is that liberal peacebuilding based on the reform of chieftaincy and decentralisation has failed to deliver effective peacebuilding mechanisms in Sierra Leone. Chieftaincy reform should have taken into consideration the specific context of the nature of chieftaincy in the country which in most cases transcends issues of leadership to one of collective identity. The decentralisation process is also fraught with a host of problems ranging from tension between the councils and the chiefs on the one hand, to the unwillingness on the part of central government to cede some of its powers to the local government. The control of central government over the councils and the decentralisation process is still very visible. The relevance of this research is that it enhances our understanding of key debates and policy intervention practices on post-war peacebuilding and state reconstruction in transition societies. It also contributes to the existing literature on post-conflict peacebuilding by positing that there is a huge challenge to the Liberal Peace paradigm in bringing about peace in war-torn societies.
  • The Application Of Polymer Particles In Industrial Processes

    Mujtaba, Iqbal M.; Steele, John E. (University of BradfordChemical Engineering, School of Engineering, Faculty of Engineering and Informatics., 2019)
    The research in this thesis considers novel innovative developments in established industrial processes that involve the use of recyclable polymeric particles as a partial replacement for aqueous media and chemicals. The application of the technology typically leads to water savings of over 80% and chemical savings of over 25%. These industrial processes may be characterised in that are considered inefficient and wasteful but nevertheless are considered economically vital. These diverse industries including laundry cleaning, leather manufacturing, textile garment processing, effluent treatment and metal beverage can manufacture. The outcomes of this research have made significant contributions to industrial best practice in such industries. In terms of academic research, the knowledge created in this thesis provides the basis for the application of CFD-DEM modelling to understand complex multi-phase and multi-component systems. In particular, the thesis advocates the application of the Free Surface Lattice Boltzmann Method for creating highly accurate simulations of multi-phase flow. In addition, the thesis offers opportunities for further research in novel plasma micro-reactors and their applications in diverse fields such as chemical synthesis, chemical engineering and biotechnology. The nature of the research is multi-disciplinary, and involved investigations across several fields including applied mathematics, biochemistry, chemistry, physics, and engineering. The projects also involved scale up from laboratory, pilot plant and full commercial scale production trials. Primary objectives were investigated through a series of six published patents. The three patents relating to the development of novel leather and textile processes were solely conceived and executed by the author. The patent related to the development of the plasma micro-reactor for ozone synthesis was conceived and executed jointly by the author and Professor Will Zimmerman (Sheffield University). The two patents related to the development of a novel metal cleaning and treatment process was conceived and executed jointly by the author and Dr. Robert Bird (Xeros Technology Group Limited).
  • Social Media and Knowledge Sharing. The Impact on Social Value Creation and Organisational Performance of UK Social Enterprises

    Wallace, James; Cornelius, Nelarine; Akhtar, Gulrez (University of BradfordFaculty of Management, Law and Social Sciences, 2019)
    Governments and society are looking, increasingly, to specialist organisations such as social enterprises to address complex social problems, leading to a rise in their numbers. These organisations regularly access difficult to reach, disadvantaged and disenfranchised communities and tend to be smaller in size and turnover than for-profit commercial organisations and typically more resource limited. The growth in corporate social responsibility and individual citizenship has helped to redress this limitation with essential altruistic resource donations from these external agencies to supplement traditional sources of support. Social media is the obvious medium for social enterprises to acquire knowledge and resources to support their social agendas. Following a sequential mixed methods design, a model is developed to appraise the impact of the various contributions from social media networks on social value creation. This model is predicated on the extant literature, mostly on for-profit organisations, contextualised and a questionnaire developed to represent social entrepreneurship from interviews with social enterprises in the UK. Data is collected from two hundred and thirty-one UK based social enterprises whose mission is to provide social value for their target populations. The model is validated for factors that lead from knowledge sharing due to social media networking to concomitant increases in social provision by fitting to these data. Findings demonstrate that social media use leads to increases in social value creation through knowledge sharing. The novel construct of enhanced organisational performance is shown as seminal in enabling shared knowledge gained from social media to be converted into increased social value.
  • From hospital to home: a mixed methods exploration of post-discharge medicines management for older people living with long-term conditions

    Silcock, Jonathan; Fylan, Beth; Smith, Heather; Karban, Kate; Tomlinson, Justine (University of BradfordSchool of Pharmacy and Medical Sciences, Faculty of Life Sciences, 2020)
    There are numerous threats to medication safety at care transitions, which are heightened for older people, because they live with multiple long-term conditions as well as polypharmacy, and have frequent hospital admissions. Whilst evidence of the severity and scale of these medicines-related problems exists, there is insufficient detail about the lived experience of post-discharge medicines management, in particular what helps or what hinders, and how better support could be enabled. This thesis, underpinned by the Medicines Research Council framework for complex intervention design, aimed to find acceptable intervention components, which would enhance patient experience. This research followed a sequential, mixed method design to: establish the evidence base through critical literature review, develop theory using an interview study grounded in behaviour change theory, and finally to model potential intervention components by expert consensus. Interviews revealed that there were gaps in current service provision, which impacted on participants’ knowledge of and capabilities with their medicines. Despite these challenges, some participants took actions to safeguard from problems after discharge. The literature review found that effective components of trialled interventions were self-management advice, post-discharge telephone follow up and medicines reconciliation. Further behaviour change techniques from the literature, alongside expert consensus and theory-driven analysis of interview findings resulted in final selection of eight potential components. Real-world implementation of these must be coupled with key changes to current healthcare practices and policy, including better engagement with patients and carers, as well as pro-active post-discharge follow-up. Future work must carefully explore how these components can be tested pragmatically.
  • Barriers and enablers to the uptake of direct oral anticoagulants (DOACs) for stroke prevention in atrial fibrillation. A qualitative study with patients and staff in three health economies

    Petty, Duncan R.; Stirling, K.; Richardson, Sue; Fylan, Beth; Rattray, Marcus; Medlinskiene, Kristina (University of BradfordSchool of Pharmacy and Medical Sciences, Faculty of Life Sciences, 2021)
    Implementation and uptake of novel and cost-effective medicines can improve patient health outcomes and healthcare efficiency. However, the relative uptake of new medicines recommended by the National Institute for Health and Care Excellence often lags behind other comparative countries’ health systems. One example is the uptake of direct oral anticoagulants (DOACs) for stroke prevention in atrial fibrillation, which was slow and had a high level of unexplained variation across different health economies in England. This research aimed to explore barriers and enablers to the uptake of DOACs from the perspectives of patients, healthcare professionals, and key stakeholders by conducting systematic and narrative reviews and semi-structured interviews. Data collected from 21 patients, 23 healthcare professionals, and 23 key stakeholders recruited from three different health economies was analysed using the Framework method. The findings identified a range of intersecting factors acting as barriers and/or enablers to the uptake DOACs. While there were a wide range of experiences and views, an agreement between patients and healthcare professionals/key stakeholders on several identified factors was observed. Attributes of the innovation, characteristics of patients and prescribers, local health economy readiness for change, implementation process, and external health system context were suggested as influences. Mapping of the findings to the Diffusion of Innovations in Service Organisations model identified 11 components for a future toolkit development to facilitate uptake of nationally recommended new medicines. This thesis highlighted the role of patients, consideration of all costs associated with new medicines, and compatibility with the health economy’s care model impact on the uptake.
  • From Cultural Imperialism to Cultural Peacebuilding. The Role of Media Within the Framework of the Responsibility to Protect Doctrine: The Case of Libya 2011

    Whitby, Simon M.; Chesters, Graeme S.; Intezar, Hannah; De Michelis, Silvia (University of BradfordFaculty of Management, Law and Social Sciences, 2020)
    This thesis undertakes a critical approach to understanding the role of media within the responsibility to protect doctrine framework. The purpose of this work is to respond to the following main two questions: Are there non-violent means that can be applied within the context of the responsibility to protect, Pillar III in particular? Does the conceptualisation of the responsibility to protect and the role assigned to the media prevent or facilitate the application of non-violence to the resolution of humanitarian crises, such as genocide, ethnic cleansing, war crimes and crimes against humanity? In order to investigate the above research questions, it adopts a nuanced Social Constructionist perspective, through which the social function of the media is highlighted. This is achieved through the application of Critical Discourse Analysis, which allowed critical engagement with the semantic position of ‘media’, ‘dialogue,’ and ‘non-violence’ within the founding documents published by the International Commission on Intervention and State Sovereignty and the United Nations that developed the concept of the responsibility to protect between 2001 and 2018. Finally, the work explored how the responsibility to protect has been discussed in selected media outlets that are reflective of two different approaches to journalism, whose underpinning principles differ substantially: mainstream and peace journalism. By adopting the same methodological approach and applying it to the case of the NATO intervention to Libya in 2011 this section of this thesis critically investigated whether there is a difference in their discourse, and, if so, what this difference is.
  • Peripheral Refractive Error and its Association with Myopia Development and Progression. An examination of the role that peripheral retinal defocus may play in the origin and progression of myopia

    Mallen, Edward A.H.; Barrett, Brendan T.; Jamal, Heshow (University of BradfordFaculty of Life Sciences, 2019)
    Purpose: Currently there are attempts to slow myopia progression by manipulating peripheral refractive error. This study proposed to establish the distribution of peripheral refractive errors in hyperopic, emmetropic and myopic children and to test the hypothesis that relative peripheral hyperopia is a risk factor in the onset and progression of myopia. Methods: Refraction was measured under non-cycloplegic conditions, at 0°, 10° (superior, inferior, temporal and nasal retina) and 30° (temporal and nasal retina), at distance and near. Central spherical equivalent refractive error (SER) was used to classify the eyes as myopic (≤ −0.75 D), emmetropic (−0.75 < SER < +0.75 D) or hyperopic (≥ +0.75 D). Relative peripheral refraction was calculated as the difference between the central (i.e. foveal) and peripheral refractive measurements. At baseline, measurements were taken from 554 children and in a subset of 300 of these same children at the follow-up visit. The time interval between initial and follow-up measurement was 9.71 ± 0.87 months. Results: Results were analysed on 528 participants (10.21 ±0.94 years old) at baseline and 286 longitudinally. At baseline, myopic children (n=61) had relative peripheral hyperopia at all eccentricities at distance and near, except at 10°-superior retina where relative peripheral myopia was observed at near. Hyperopic eyes displayed relative peripheral myopia at all eccentricities, at distance and near. The emmetropes showed a shift from relative peripheral myopia at distance to relative peripheral hyperopia at near at all eccentricities, except at 10°-superior retina, where the relative peripheral myopia was maintained at near. In the longitudinal data analysis, myopes who became more myopic did not show greater relative peripheral hyperopia at baseline compared with myopic sub-groups whose central refraction remained stable. Conclusions: The peripheral refractive profile differences between different refractive groups that are reported in other studies have been confirmed in this study. Relative peripheral hyperopia is not found to be a significant risk factor in the onset or progression of myopia in children.
  • In-line process measurements for injection moulding control. In-line rheology and primary injection phase process measurements for injection moulding of semi-crystalline thermoplastics, using instrumented computer monitored injection moulding machines, for potential use in closed loop process control

    Coates, Philip D.; Speight, Russell G. (University of BradfordDepartment in Mechanical and Manufacturing Engineering, 1993)
    In-line rheological and process measurements are studied, during the primary injection phase, as a potential aid to closed loop process control for injection moulding. The feasibilities of attaining rheological and process measurements of sufficient accuracy and precision for use in process control are investigated. The influence of rheological and process measurements on product quality are investigated for semi-crystalline thermoplastic materials. A computer based process and machine parameter monitoring system is utilised to provide accurate and precise process data for analysis
  • Education Reform in England and the Transformation of School Teachers’ Working Lives: A Labour Process Perspective

    Ford, Jackie M.; Smith, Andrew J.; Morrell, Sophie E. (University of BradfordFaculty of Management, Law and Social Sciences, 2020)
    The academy school programme, OFSTED’s use of school performance data, and performance management and performance related pay reforms are dramatically transforming the work and employment landscape in teaching. Yet there is limited knowledge of teachers’ experiences of work in relation to this context. The purpose of this thesis is to explore the impact of these education reforms on school teachers’ working lives through a labour process perspective. A critical realist ethnography of an inner-city secondary academy school was conducted over four months. This comprised a six-week shadowing phase, document collection and 26 semi-structured interviews with Teachers, Managers, HR and Trade Union Representatives. Findings reveal that the removal of a contextual value added measure from school performance metrics leads to an increase in teachers’ workloads and an extension of their working hours. This is compounded by an unofficial erosion of teachers’ directed working time that infiltrates through the academy trust. Pressures on workload also stem from management-led initiatives generated by appraisals in leadership programmes. Furthermore, teachers’ work becomes standardised and re-organised through the heterarchical multi-academy trust model in an effort to improve the school’s OFSTED rating. Performance related pay reforms act as a parallel instigator to the standardisation of work, polarising the creative and mundane aspects of teaching across the workforce, whilst oppositional orientations to work form as the majority of teachers align with a shared sense of commitment to work. This thesis amalgamates labour process theory with the hollowing out thesis, making key theoretical, conceptual, empirical and methodological contributions, alongside practical recommendations.
  • Crystal and Particle Engineering: Pharmaceutical Cocrystals through Antisolvent and Liquid-Liquid Phase Separation Technologies

    Paradkar, Anant R.; Kelly, Adrian L.; Vangala, Venu R.; Sajid, Muhammad A. (University of BradfordFaculty of Life Sciences, 2019)
    The effects of polymer concentration and solvents on cocrystal morphology of low solubility drugs were investigated, both of which had an impact. The melting temperatures also decreased with increasing polymer concentration. Placing the binding agent, benzene, at different interfaces induced morphological changes, such as formation of porous cocrystals. Previously liquid-liquid phase separation (LLPS) has been reported as a hindrance in the crystallisation process impeding further development. A phase diagram was constructed, and different phases were categorised into 4 types. After separation of the highly concentrated amorphous Oil Phase II, it was prone to gradual crystallisation. Crystallisation took place over 30-60 minutes; this allowed the in-situ monitoring. A novel cocrystallisation technique was developed; from (LLPS). Cocrystals of indomethacin with saccharin and nicotinamide were obtained by mixing Oil Phase II with the coformers. In-situ monitoring by spectroscopic had gradual changes in spectra; characteristic peaks increased in height and area with the formation of crystals until the reaction was complete. With crystal formation, the XRD spectra gradually had a sharper baseline due to a decrease in the amorphous indomethacin. The photoluminescence (PL) spectra displayed several peaks coupling into one large hump together with increasing intensity as the sample crystallised. There was a shift in the peak absorbance of the pure drug crystals obtained from LLPS and the indomethacin:saccharin cocrystal obtained from LLPS. Amorphous stabilisation was achieved by mixing polymer (PVP) with Oil Phase II. There were no changes to the XRD diffractogram as the sample did not undergo crystallisation.
  • Designing an Operations Performance Management System – A case-study of a leading global automotive parts supplier

    Hussain, Zahid I.; Gast, Carsten G. (University of BradfordDepartment – School of Management, 2019)
    This research focuses on a contemporary Operations Performance Management System (OPMS) designed for a leading global automotive parts supplier. It synthesises an integrated and holistic OPMS to increase the effectiveness and efficiency of the automotive parts supplier to ultimately improve financial margin. The study is motivated by the need of an process-oriented automotive parts supplier to excel in regards to its operations management to ultimately secure a best-in-class cost basis in times of significant changes in the automotive industry. The research design is based on a qualitative single case-study and deploys semistructured interviews with the management of the case-study organisation. In addition, hundreds of documents were analysed to evidence the creation of the OPMS. Finally, participant observation was used to allow for triangulation and contextualisation of findings. The findings reveal a contemporary OPMS. It presents an intelligent and integrated steering logic from corporate level to single operational processes. It integrates performance measurement and management in acknowledgement of the specific needs to the case-study organisation. The overall aim of this thesis is to make a practical contribution to this area as achieved by the presented OPMS. This study extends the existing literature by contributing a customised, highlyintegrated OPMS for a process-oriented automotive parts supply industry. It embeds the ‘Target Costing Methodology’ as an example for a performance management tool into the OPMS. Furthermore, the study explores the impact of digitalisation on OPMS. This research has synthesised an OPMS that emphasises a shift towards intelligent performance measurement for achieving value in the chain, in areas such as procurement and manufacturing. This shift is strongly influenced by digital transformation, which is not yet holistically commanded by the case-study organisation. The research does shed light upon how to optimise resource utilisation based on increased operational focus and managerial accountability. This approach will lead to continual organisational learning as part of the ‘Plan-Do-Check-Action’ management process.
  • Ultra-Wideband Imaging System For Medical Applications. Simulation models and Experimental Investigations for Early Breast Cancer & Bone Fracture Detection Using UWB Microwave Sensors

    Abd-Alhameed, Raed A.; Noras, James M.; Mirza, Ahmed F. (University of BradfordFaculty of Engineering and Informatics, 2019)
    Near field imaging using microwaves in medical applications is of great current interest for its capability and accuracy in identifying features of interest, in comparison with other known screening tools. Many imaging methods have been developed over the past two decades showing the potential of microwave imaging in medical applications such as early breast cancer detection, analysis of cardiac tissues, soft tissues and bones. Microwave imaging uses non-ionizing ultra wideband (UWB) electromagnetic signals and utilises tissue-dependent dielectric contrast to reconstruct signals and images using radar-based or tomographic imaging techniques. Microwave imaging offers low health risk, low operational cost, ease of use and user-friendliness. This study documents microwave imaging experiments for early breast cancer detection and bone fracture detection using radar approach. An actively tuned UWB patch antenna and a UWB Vivaldi antenna are designed and utilised as sensing elements in the aforementioned applications. Both UWB antennas were developed over a range of frequency spectrum, and then characteristics were tested against their ability for microwave imaging applications by reconstructing the 3D Inversion Algorithm. An experiment was conducted using patch antenna to test the detection of variable sizes of cancer tissues based on a simple phantom consisting of a plastic container with a low dielectric material emulating fatty tissue and high dielectric constant object emulating a tumour, is scanned between 4 to 8 GHz with the patch antenna. A 2-D image of the tumour is constructed using the reflected signal response to visualize the location and size of the tumour. A Vivaldi antenna is designed covering 3.1 to 10.6 GHz. The antenna is tested via simulation for detecting bone fractures of various sizes and 2-D images are generated using reflected pulses to show the size of fracture. The Vivaldi antenna is optimised for early breast cancer detection and detailed simulated study is carried out using different breast phantoms and tumour sizes. Simulations are backed with the experimental investigation with the test setup used for patch antenna. Generated images for simulations and experimental investigation show good agreement, and show the presence of tumour with good location accuracy. Measurements indicate that both prototype microwave sensors are good candidates for tested imaging applications.
  • Effect of Process Parameters and Material Attributes on Crystallisation of Pharmaceutical Polymeric Systems in Injection Moulding Process. Thermal, rheological and morphological study of binary blends polyethylene oxide of three grades; 20K, 200K and 2M crystallised under various thermal and mechanical conditions using injection moulding

    Gough, Timothy D.; Isreb, Mohammad; Mkia, Abdul R. (University of BradfordFaculty of Life Sciences. School of Pharmacy and Medical Sciences, 2019)
    Crystallisation is gaining a lot of interest in pharmaceutical industry to help designing active ingredients with tailored physicochemical properties. Many factors have been found to affect the crystallisation process, including process parameters and material attributes. Several studies in the literature have discussed the role of these parameters in the crystallisation process. A comprehensive study is still missing in this field where all the significant terms are taken into consideration, including the square effect and the interaction terms between different parameters. In this study, a thorough investigation into the main factors affecting crystallisation of a polymeric system, processed via injection moulding, was presented and a sample of response optimisation was introduced which can be mimicked to suite a specific need. Three grades of pure polyethylene oxide; 20K, 200K and 2M, were first characterised using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD) and shear rheometry. The onset of degradation and the rate varied according to molecular weight of polyethylene oxide (PEO). The peak melting temperature and the difference in enthalpy between melting and crystallisation were both in a direct proportion with PEO molecular weight. PEO200K and PEO2M struggle to recrystallise to the same extent of the original state at the tested cooling rates, while PEO20K can retain up to a similar crystallinity degree when cooled at 1 °C/min. Onset of crystallisation temperature (Tc1) was high for PEO2M and the difference between the 20K and 200K were pronounced at low cooling rate (20K is higher than 200K). The rheometer study showed that PEO2M has a solid-like structure around melting point which explains the difficulty in processing this grade at a low temperature via IM. PEO20K was almost stable within the strain values studied (Newtonian behaviour). For higher grades, PEO showed a shear thinning behaviour. The complex viscosity for PEO2M is characterised by a steeper slope compared to PEO200K, which indicates higher shear thinning sensitivity due to higher entanglement of the longer chains. For binary blends of PEO, the enthalpy of crystallisation studied by DSC was in direct proportion to the lowest molecular weight PEO content (PEOL %) in PEO20K/200K and PEO20K/2M blends. The effect of PEOL% on Tc1 became slightly pronounced for PEO20K-2M blends where Tc1 exhibited slight inverse proportionality to PEOL% and it became more significant for PEO200K-2M blends. It was interesting to find that Tc1 for the blends did not necessarily lie between the values of the homopolymers. In all binary blends, Tc1 was inversely proportional to cooling rate for the set of cooling rates tested. Thermal analysis using hot stage polarised light microscopy yields different behaviours of various PEO grades against the first detection of crystals especially where the lowest grade showed highest detection temperature. Visual observation of PEO binary blends caplets processed at various conditions via injection moulding (IM) showed the low-quality caplets processed at mould temperature above Tc1 of the sample. The factors affecting crystallisation of injection moulded caplets were studied using response surface methodology for two responses; peak melting temperature (Tm) and relative change in crystallinity (∆Xc%) compared to an unprocessed sample. Mould temperature (Tmould) was the most significant factor in all binary blend models. The relationship between Tmould and the two responses was positive non-linear at the Tmould ˂ Tc1. Injection speed was also a significant factor for both responses in PEO20K-200K blends. For Tm, the injection speed had a positive linear relationship while the opposite trend was found for ∆Xc%. The interaction term found in the RSM study for all models was only between the injection speed and the PEOL % which shows the couple effect between these two factors. Molecular effect was considered a significant factor in all ∆Xc% models across the three binary blends. The order of ∆Xc% sensitivity to the change in PEOL% was 3, 5 and 7 % for 20K-200K, 200K-2M and 20K-2M.
  • Novel PLA-based materials with improved thermomechanical properties and processability through control of morphology and stereochemistry. A study in improving toughness and processability of PLA by blending with biodegradable polymers and the two PLA enantiomers PLLA and PDLA to accelerate crystallinity and heat resistance

    Kelly, Adrian L.; Gough, Timothy D.; Kassos, Nikolaos (University of BradfordFaculty of Engineering and informatics, 2019)
    Polylactic acid (PLA) is an aliphatic polyester, derived from sustainable natural sources that is biodegradable and can be industrially composted. This material has been in the spotlight recently due to its sustainability and properties. However it has been invented in 1932 by Carothers and then patented by DuPont in 1954 (Standau et al. 2019). The properties of this material though limit its use for applications mainly in the medical sector and in some cases single use packaging. In this research, PLA based blends with improved rheological and thermomechanical properties are investigated. The focus is based in proposing strategies in improving these properties based on commercial methods and processing techniques. In this work, commercial grade PLA has been blended with polycaprolactone (PCL) and polybutylene succinate (PBS) in binary and ternary formulations via twin screw extrusion. PCL has been known to act as an impact modifier for PLA, but to cause a corresponding reduction in strength. Results showed that the binary PLA blends containing PBS and PCL, had reduced viscosity, elastic modulus and strength, but increased strain at break and impact strength. Morphological and thermal analysis showed that the immiscibility of these additives with PLA caused these modifications. Incorporation of a small loading of PBS had a synergistic effect on the PLA-PCL blend properties. Miscibility was improved and enhanced mechanical properties were observed for a ternary blend containing 5wt% of both PBS and PCL compared to binary blends containing 10% of each additive. To increase heat resistance of PLA, the material’s crystallinity has to be increased. However PLA has a relatively slow crystallisation rate making it difficult and expensive to be used in commercial applications where heat resistance is needed. For this reason the chiral nature of PLA has been used to investigate the effect of stereochemistry of PLA in crystallisation. Optically pure PDLA was added to its enantiomer in small amounts (up to 15%) and the properties and crystallisation mechanism of these blends was investigated. Results showed that the addition of PDLA accelerated crystallinity and developed a stucture that increased heat resistance, melt strength and stiffness. Finally, a processing model of developing a fully stereocomplex PLA part based in commercial techniques is proposed. Injection moulded PLA showed even higher heat resistance without the need of further processing the product (increasing crystallinity).
  • The use of Silent Substitution in measuring isolated cone- and rod- Human ERGs

    McKeefry, Declan J.; Tripathy, Srimant P.; Barrett, Brendan T.; Kommanapalli, Deepika (University of BradfordFaculty of Life Sciences, 2018)
    After over a decade of its discovery, the Electroretinogram (ERG) still remains the objective tool that is conventionally used in assessment of retinal function in health and disease. Although there is ongoing research in developing ERG recording techniques, interpretation and clinical applications, there is still a limited understanding on how each photoreceptor class contribute to the ERG waveform and their role and/or susceptibilities in various retinal diseases still remains unclear. Another limitation with currently used conventional testing protocols in a clinical setting is the requirement of an adaptation period which is time consuming. Furthermore, the ERG responses derived in this manner are recorded under different stimulus conditions, thus, making comparison of these signals difficult. To address these issues and develop a new testing method, we employed silent substitution paradigm in obtaining cone- and rod- isolating ERGs using sine- and square- wave temporal profiles. The ERGs achieved in this manner were shown to be photoreceptor-selective. Furthermore, these responses did not only provide the functional index of photoreceptors but their contributions to their successive postreceptoral pathways. We believe that the substitution stimuli used in this thesis could be a valuable tool in functional assessment of individual photoreceptor classes in normal and pathological conditions. Furthermore, we speculate that this method of cone/rod activity isolation could possibly be used in developing faster and efficient photoreceptor-selective testing protocols without the need of adaptation.
  • The Presence and Use of Interactive Features on Kurdish News Websites in the Iraqi Kurdistan region. A case study of interactivity of news Kurdish websites of the Iraqi Kurdistan Region

    Reeve, Carlton; Salih, Hunar R.S. (University of BradfordDepartment of Media Design and Technology. Faculty of Engineering and Informatics, 2018)
    Internet has emerged as an interactive platform. Thus, new communication technologies are challenging the traditional media with interactive devices turning online journalism into a rich media environment. While new information technologies have enabled media organisations to use interactive features in the constructed presentation of news websites, few news websites in the Iraqi Kurdistan region are maximizing such features. Also, this thesis argues that despite the lack of a good infrastructure in the field of communication technology and the Internet in the Iraqi Kurdistan Region (IKR), online journalism has become a major part of Kurdish media outlets and distinctive from traditional media because of its interactive nature. The study presented in this thesis focus on interactivity in online journalism by examine interactive features of Kurdish news websites of the (IKR) and analyses how news is presented and to what extent these news websites tried to apply the interactive features on their hompages and inside the news pages. The level of interactivity of those Kurdish websites was also measured using several dimensions of interactivity by conducting web-based content analysis. The analysis of the qualitative part based on in-depth interviews with Kurdish reporters, editors, editor in chiefs, media experts and web developers. The findings show that the Kurdish news websites did not fully utilize and enhance interactive features in online journalism.
  • Design and Analysis of Anomaly Detection and Mitigation Schemes for Distributed Denial of Service Attacks in Software Defined Network. An Investigation into the Security Vulnerabilities of Software Defined Network and the Design of Efficient Detection and Mitigation Techniques for DDoS Attack using Machine Learning Techniques

    Awan, Irfan U.; Hu, Yim Fun; Pillai, Prashant; Sangodoyin, Abimbola O. (University of BradfordFaculty of Engineering and Informatics, 2019)
    Software Defined Networks (SDN) has created great potential and hope to overcome the need for secure, reliable and well managed next generation networks to drive effective service delivery on the go and meet the demand for high data rate and seamless connectivity expected by users. Thus, it is a network technology that is set to enhance our day-to-day activities. As network usage and reliance on computer technology are increasing and popular, users with bad intentions exploit the inherent weakness of this technology to render targeted services unavailable to legitimate users. Among the security weaknesses of SDN is Distributed Denial of Service (DDoS) attacks. Even though DDoS attack strategy is known, the number of successful DDoS attacks launched has seen an increment at an alarming rate over the last decade. Existing detection mechanisms depend on signatures of known attacks which has not been successful in detecting unknown or different shades of DDoS attacks. Therefore, a novel detection mechanism that relies on deviation from confidence interval obtained from the normal distribution of throughput polled without attack from the server. Furthermore, sensitivity analysis to determine which of the network metrics (jitter, throughput and response time) is more sensitive to attack by introducing white Gaussian noise and evaluating the local sensitivity using feed-forward artificial neural network is evaluated. All metrics are sensitive in detecting DDoS attacks. However, jitter appears to be the most sensitive to attack. As a result, the developed framework provides an avenue to make the SDN technology more robust and secure to DDoS attacks.
  • International Joint Venture (IJV) Control Design: A Case Study of an Emerging Market IJV

    Wang, Chengang; Owens, Martin D.; Chu, Irene; Ekpo, Itoro U. (University of BradfordFaculty of Management, Law and Social Science, 2019)
    This study aims to explore the various factors that influence the international joint venture (IJV) parent firms to use a specific control mechanism in an emerging market (EM). The study adopted a single case study design involving an IJV between a Nigerian firm as the local partner and a Chinese firm as the foreign partner. Data was collected through twenty semi structured interviews from both the parent firms and the IJV; and complemented by observations of the IJV activities, relevant information from newspapers; magazines; company brochures and newsletters; and website of the parent firms, IJV and the government regulating body. The study revealed that the design of formal and social control is influenced by a range of factors identified in the literature. This includes resource contribution and bargaining power, previous experience of the IJV managers, knowledge transfer, trust-building, environmental uncertainty, and institutional forces. In contrast to findings from existing studies, this study also reveals that a combination of factors can influence the use of a particular control mechanism. By examining the types of control exercised by each partner and the antecedent of each control type, this study complements prior research by incorporating insights from transaction cost theory, resource dependency theory, social exchange theory, institutional theory and organisational lerning perspective to provide a more integrative explanation of IJV control design. Specifically, it explains how one partner develops certain types of formal and social control according to its individual resource contribution and dependency and can adjust controls to achieve its various objectives.

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