Now showing items 21-40 of 1285

    • Investigation of Integrated Decoupling Methods for MIMO Antenna Systems. Design, Modelling and Implementation of MIMO Antenna Systems for Different Spectrum Applications with High Port-to-Port Isolation Using Different Decoupling Techniques

      Abd-Alhameed, Raed A.; Excell, Peter S.; McEwan, Neil J.; Noras, James M.; Salah, Adham M.S. (University of BradfordFaculty of Engineering and Informatics, 2019)
      Multiple-Input-Multiple-Output (MIMO) antenna technology refers to an antenna with multiple radiators at both transmitter and receiver ends. It is designed to increase the data rate in wireless communication systems by achieving multiple channels occupying the same bandwidth in a multipath environment. The main drawback associated with this technology is the coupling between the radiating elements. A MIMO antenna system merely acts as an antenna array if the coupling between the radiating elements is high. For this reason, strong decoupling between the radiating elements should be achieved, in order to utilize the benefits of MIMO technology. The main objectives of this thesis are to investigate and implement several printed MIMO antenna geometries with integrated decoupling approaches for WLAN, WiMAX, and 5G applications. The characteristics of MIMO antenna performance have been reported in terms of scattering parameters, envelope correlation coefficient (ECC), total active reflection coefficient (TARC), channel capacity loss (CCL), diversity gain (DG), antenna efficiency, antenna peak gain and antenna radiation patterns. Three new 2×2 MIMO array antennas are proposed, covering dual and multiple spectrum bandwidths for WLAN (2.4/5.2/5.8 GHz) and WiMAX (3.5 GHz) applications. These designs employ a combination of DGS and neutralization line methods to reduce the coupling caused by the surface current in the ground plane and between the radiating antenna elements. The minimum achieved isolation between the MIMO antennas is found to be better than 15 dB and in some bands exceeds 30 dB. The matching impedance is improved and the correlation coefficient values achieved for all three antennas are very low. In addition, the diversity gains over all spectrum bands are very close to the ideal value (DG = 10 dB). The forth proposed MIMO antenna is a compact dual-band MIMO antenna operating at WLAN bands (2.4/5.2/5.8 GHz). The antenna structure consists of two concentric double square rings radiating elements printed symmetrically. A new method is applied which combines the defected ground structure (DGS) decoupling method with five parasitic elements to reduce the coupling between the radiating antennas in the two required bands. A metamaterial-based isolation enhancement structure is investigated in the fifth proposed MIMO antenna design. This MIMO antenna consists of two dual-band arc-shaped radiating elements working in WLAN and Sub-6 GHz 5th generation (5G) bands. The antenna placement and orientation decoupling method is applied to improve the isolation in the second band while four split-ring resonators (SRRs) are added between the radiating elements to enhance the isolation in the first band. All the designs presented in this thesis have been fabricated and measured, with the simulated and measured results agreeing well in most cases.
    • Machine Learning-based Feature Selection and Optimisation for Clinical Decision Support Systems. Optimal Data-driven Feature Selection Methods for Binary and Multi-class Classification Problems: Towards a Minimum Viable Solution for Predicting Early Diagnosis and Prognosis

      Neagu, Daniel; Campean, I. Felician; Parisi, Luca (University of BradfordFaculty of Engineering and Informatics, 2019)
      This critical synopsis of prior work by Luca Parisi is submitted in support of a PhD by Published Work. The work focuses on deriving accurate, reliable and explainable clinical decision support systems as minimum clinically viable solutions leveraging Machine Learning (ML) and evolutionary algorithms, for the first time, to facilitate early diagnostic predictions of Parkinson's Disease and hypothermia in hospitals, as well as prognostic predictions of optimal postoperative recovery area and of chronic hepatitis. Despite the various pathological aetiologies, the underlying capability of ML-based algorithms to serve as a minimum clinically viable solution for predicting early diagnosis and prognosis has been thoroughly demonstrated. Feature selection (FS) is a proven method for increasing the performance of ML-based classifiers for several applications. Although advances in ML, such as Deep Learning (DL), have denied the usefulness of any extrinsic FS by incorporating it in their architectures, e.g., convolutional filters in convolutional neural networks, DL algorithms often lack the required explainability to be understood and interpreted by clinicians within the context of the diagnostic and prognostic tasks of interest. Their relatively complicated architectures, the hardware required for running them and the limited explainability or interpretability of their architectures, the decision-making process – although as assistive tools - driven by the algorithms’ training and predictive outcomes have hindered their application in a clinical setting. Luca Parisi’s work fills this translational research gap by harnessing the explainability of using traditional ML- and evolutionary algorithms-based FS methods for improving the performance of ML-based algorithms and devise minimum viable solutions for diagnostic and prognostic purposes. The work submitted here involves independent research work, including collaborative studies with Marianne Lyne Manaog (MedIntellego®) and Narrendar RaviChandran (University of Auckland). In particular, conciliating his work as a Senior Artificial Intelligence Engineer and volunteering commitment as the President and Research Committee Leader of a student-led association named the “University of Auckland Rehabilitative Technologies Association”, Luca Parisi decided to embark on most research works included in this synopsis to add value to society via accurate, reliable and explainable, hence clinically viable applications of AI. The key findings of these studies are: (i) ML-based FS algorithms are sufficient for devising accurate, reliable and explainable ML-based classifiers for aiding prediction of early diagnosis for Parkinson’s Disease and chronic hepatitis; (ii) evolutionary algorithms-based optimisation is a preferred method for improving the accuracy and reliability of decision support systems aimed at aiding early diagnosis of hypothermia; (iii) evolutionary algorithms-based optimisation methods enable to devise optimised ML-based classifiers for improving postoperative discharge; (iv) whilst ML-based algorithms coupled with ML based FS methods are the minimum clinically viable solution for binary classification problems, ML-based classifiers leveraging evolutionary algorithms for FS yield more accurate and reliable predictions, as reducing the search space and overlapping regions for tackling multi-class classification problems more effectively, which involve a higher number of degrees of freedom. Collectively, these findings suggest that, despite advances in ML, state-of-the-art ML algorithms, coupled with ML-based or evolutionary algorithms for FS, are enough to devise accurate, reliable and explainable decision support systems for performing both an early diagnosis and a prediction of prognosis of various pathologies.
    • The Impact of Training in Person-Centred Dementia Care and Supervision on Burnout in Nursing Home Nurses: A Mixed Methods Study

      Oyebode, Jan R.; Downs, Murna G.; Smythe, Analisa (University of BradfordFaculty of Health Studies, 2018)
      Background: There is significant concern about nurse burnout in nursing homes. There has been little research to investigate whether training in person-centred care and supervision can reduce nursing home nurses’ burnout. Aims: To adapt training to be suitable for nursing home nurses and evaluate the impact of training and supervision on burnout and related outcomes. Study Design: Focus groups with nursing home nurses were used to inform adaptation of the training. Mixed methods were used to evaluate the impact of training and supervision employing a convergent parallel design, including a Randomised Controlled Trial with quantitative measures (primary outcome measure: the Maslach Burnout Inventory) to assess effectiveness and exploration of subjective experience using qualitative interviews. The findings of the RCT and qualitative interviews were then compared to determine the convergences and divergences. Findings: The training was adapted to include content on leadership and stress management. Hypotheses that the interventions would reduce burnout and impact on other quantitative outcomes were not supported. Qualitative interviews with nursing home nurses about training indicated that the nurses reported reduced burnout, enhanced self-efficacy, reduced isolation, better team working, more informed person centred dementia care and enhanced leadership. Nurses’ views on the impact of supervision included a range of benefits. There was convergence between quantitative measurement and subjective experience indicting significant levels of burnout, but divergence in terms of the impact of training in person-centred care and supervision. Conclusions: My study demonstrates that burnout is a significant issue for nursing home nurses in the UK. There was divergence in my findings in terms of the impact of training in person-centred care and supervision. The hypotheses about training and supervision having positive impact on burn-out were rejected. However, the qualitative findings suggest that nursing home nurses experienced positive benefits from the person-centred training and supervision, in particular on their sense of burnout, their approach to care and leadership skills. Recommendations are made regarding research, training and policy to address burnout in nursing home nurses.
    • Creation of controlled polymer extrusion prediction methods in fused filament fabrication. An empirical model is presented for the prediction of geometric characteristics of polymer fused filament fabrication manufactured components

      Whiteside, Benjamin R.; Coates, Philip D.; Caton-Rose, Philip D.; Hebda, Michael J. (University of BradfordFaculty of Engineering and Informatics, 2019)
      This thesis presents a model for the procedures of manufacturing Fused Filament Fabrication (FFF) components by calculating required process parameters using empirical equations. Such an empirical model has been required within the FFF field of research for a considerable amount of time and will allow for an expansion in understanding of the fundamental mathematics of FFF. Data acquired through experimentation has allowed for a data set of geometric characteristics to be built up and used to validate the model presented. The research presented draws on previous literature in the fields of additive manufacturing, machine engineering, tool-path programming, polymer science and rheology. Combining these research fields has allowed for an understanding of the FFF process which has been presented in its simplest form allowing FFF users of all levels to incorporate the empirical model into their work whilst still allowing for the complexity of the process. Initial literature research showed that Polylactic Acid (PLA) is now in common use within the field of FFF and therefore was selected as the main working material for this project. The FFF technique, which combines extrusion and Computer Aided Manufacturing (CAM) techniques, has a relatively recent history with little understood about the fundamental mathematics governing the process. This project aims to rectify the apparent gap in understanding and create a basis upon which to build research for understanding complex FFF techniques and/or processes involving extruding polymer onto surfaces.
    • By the Head of a Spirited Horse: A Biocultural Analysis of Horse-Depositions as Reflections of Horseman Identities in Early Britain (Iron Age to Early Medieval Period)

      Not given; Cross, Pamela J. (University of BradfordFaculty of Life Sciences, School of Archaeological and Forensic Sciences, 2018)
      Horse-depositions were examined to explore the development of human-horse relationships in early Britain using a multidisciplinary approach (osteological, archaeological, historical and ethnographical) to interpret these relationships as part of Horseman identities in the Iron Age, Roman and medieval periods. Medieval Horseman-burials are an established phenomenon and considered an Anglo-Saxon import in Britain which expressed a general elite-warrior male status. However, Horseman-burials form an exclusive minority which suggest not a general warrior elite but specific subgroups and/or traditions potentially rooted in earlier practices. Husbandry, transportation-use and ritual practices were also investigated. Horses and horse-use were evaluated via stature and correlations with sex. The results indicated sexual dimorphism should be considered when interpreting horse stature. It is hypothesised that generally females were pastured breeding-stock while males were transportation-stock which received supplemental nutrition and care. Males were/are generally larger than females, and size disparity was probably heightened by such gendered horse-use practices. Overall, it appears females were 1.3m or less, and horses over 1.3m were males. Horse-depositional patterns in human, particularly funerary, spaces were analysed. Horse deposition often had ritual components and practices changed over time reflecting changing Horseman identities, particularly during the Roman period. Roman-British interactions, the destruction of native-elite chariot-warfare identities and the development of native-auxiliary groups refocused Horseman identities on mounted-warfare. This change from driver to rider, a more intimate relationship, appears reflected by the development of human-horse burials and Horseman identities linked to auxiliary-native cultural groups which incorporated Roman equites ideals with native-auxiliary and imported Eurasian Horseman traditions.
    • Open Innovation Practices and Innovation Performance: A Dynamic Capabilities Approach

      Wang, Chengang; Pillai, Kishore G.; Ovuakporie, Oghogho D. (University of BradfordFaculty of Management, Law and Social Sciences, 2018)
    • An Experimental Study on the Effects of Heat and Chemical Inhibitors on the Flow Behaviour of Waxy Crude Oils. The Effects of Heat and Chemical Inhibitors on the Rheological Properties of Waxy Crude Oils with regard to Pumping in Pipelines

      Benkreira, Hadj; Al-Hengari, S.; Mohamed, Fathia A.B. (University of BradfordFaculty of Engineering and Informatics, 2019)
      Waxy crude oils (1/3 of oil produced worldwide), pumping through pipelines considered risky operation due to the crude wax content (15-40 wt.%) and to the temperature at which wax supersaturates and precipitates, leading to the danger of pipe blockage, eventually resulting, in multimillion dollars loss in production and maintenance. This research undertaken to develop operational strategy of waxy crude pipelines, considering the crude and crude gel properties and flow conditions. The research problem was approached by characterizing the crude gel with and without additives using chromatography (GC), differential scanning calorimetry (DSC), cross polarised microscopy (CPM), controlled stress and oscillatory shear rheology (CSR and OSR), the principal parameters being the crude temperature and the rate at which the crude was cooled. GC and DSC were useful in establishing wax composition, content and wax appearance temperature (WAT). Control stress rheometer proved to be the most appropriate as it measured the reduction in apparent viscosity at full production (10-50 s-1 shear rate), near shutdown (1 s-1 ) and yielding when the oil was statically cooled. On this basis, it was established that the wax inhibitor was the most effective. CPM revealed that only the wax inhibitor changed the structure of the gel, disrupting its otherwise knitted crystal network. Dilution with the light crude oil merely reduced the wax content and the pour point depressant reduced the gelling temperature. OSR provided a check on CSR and confirmed the gelation temperature measured. CSR provided the yield stress measured, it also provided comprehensive data that can be used for theoretical modelling of this complex flow.
    • Behaviour of continuous concrete deep beams reinforced with GFRP bars

      Ashour, Ashraf F.; Sheehan, Therese; Shalookh, Othman H. Zinkaah (University of BradfordFaculty of Engineering and Informatics, 2019)
    • Discourses of Power and Representation in British Broadcasting Corporation Documentary Practices: 1999-2013

      Not given; Thornton, Karen D. (University of BradfordFaculty of Engineering and Informatics, 2018)
      This dissertation re-evaluates the ways in which contemporary television documentary practices engage their audience. Bringing together historical frameworks, and using them to analyse a range of examples not considered together within this context previously, the main finding is that the use of spectacle to engage the audience into a visceral response cuts across all of the examples analysed, regardless of the subject matter being explored. Drawing on a media archaeological approach, the dissertation draws parallels with the way in which pre-cinema engaged an audience where the primary point of engagement came from the image itself, rather than a narrative. Within a documentary context, which is generally understood as a genre which is there to educate or inform an audience, the primacy of spectacle calls for a re-evaluation of the form and function of documentary itself. Are twenty-first century documentary practices manufacturing an emotional connection to engage the audience over attempting to persuade with reasoning and logic? The answer contained within this dissertation is that they are.
    • Big Social Data Analytics: A Model for the Public Sector

      Kamala, Mumtaz A.; Tassabehji, Rana; Bin Saip, Mohamed A. (University of BradfordFaculty of Engineering and Informatics, 2019)
      The influence of Information and Communication Technologies (ICTs) particularly internet technology has had a fundamental impact on the way government is administered, provides services and interacts with citizens. Currently, the use of social media is no longer limited to informal environments but is an increasingly important medium of communication between citizens and governments. The extensive and increasing use of social media will continue to generate huge amounts of user-generated content known as Big Social Data (BSD). The growing body of BSD presents innumerable opportunities as well as challenges for local government planning, management and delivery of public services to citizens. However, the governments have not yet utilised the potential of BSD for better understanding the public and gaining new insights from this new way of interactions. Some of the reasons are lacking in the mechanism and guidance to analyse this new format of data. Thus, the aim of this study is to evaluate how the body of BSD can be mined, analysed and applied in the context of local government in the UK. The objective is to develop a Big Social Data Analytics (BSDA) model that can be applied in the case of local government. Data generated from social media over a year were collected, collated and analysed using a range of social media analytics and network analysis tools and techniques. The final BSDA model was applied to a local council case to evaluate its impact in real practice. This study allows to better understand the methods of analysing the BSD in the public sector and extend the literature related to e-government, social media, and social network theory
    • Mechanical, thermal and acoustic properties of rubberised concrete incorporating nano silica

      Ashour, Ashraf F.; Khan, Amir; Dai, Xianghe; El-Khoja, Amal M.N. (University of BradfordFaculty of Engineering and Informatics, 2019)
      Very limited research studies have been conducted to examine the behaviour of rubberised concrete (RuC) with nano silica (NS) and addressed the acoustic benefits of rubberised concrete. The current research investigates the effect of incorporating colloidal nano silica on the mechanical, thermal and acoustic properties of Rubberised concrete and compares them with normal concrete (NC). Two sizes of rubber were used RA (0.5 – 1.5 mm) and RB (1.5 – 3 mm). Fine aggregate was replaced with rubber at a ratio of 0%, 10%, 20% and 30% by volume, and NS is used as partial cement replacement by 0%, 1.5% and 3%. A constant water to cement ratio of 0.45 was used in all concrete mixes. Various properties of rubberised concrete, including the density, water absorption, the compressive strength, the flexural strength, splitting tensile strength and the drying shrinkage of samples was studied as well as thermal and acoustic properties. Experimental results of compressive strength obtained from this study together with collected comprehensive database from different sources available in the literature were compared to five existing models, namely Khatib and Bayomy- 99 model, Guneyisi-04 model, Khaloo-08 model, Youssf-16 model, and Bompa-17 model. To assess the quality of predictive models, influence of rubber content on the compressive strength is studied. An artificial neural network (ANN) models were developed to predict compressive strength of RuC using the same data used in the existing models. Three ANN sets namely ANN1, ANN2 and ANN3 with different numbers of hidden layer neurons were constructed. Comparison between the results given by the ANN2 model and the results obtained by the five existing predicted models were presented. A finite element approach is proposed for calculating the transmission loss of concrete, the displacement in the solid phase and the pressure in the fluid phase is investigated. The transmission loss of the 50mm concrete samples is calculated via the COMSOL environment, the results from the simulation show good agreement with the measured data. The results showed that, using up to 20% of rubber as fine aggregate with the addition of 3% NS can produce a higher compressive strength than the NC. Experimental results of this research indicate that incorporating nano silica into RuC mixes enhance sound absorption and thermal conductivity compared to normal concrete (NC) and rubberised concrete without nano silica. This work suggests that it is possible to design and manufacture concrete which can provide an improvement to conventional concrete in terms of the attained vibro-acoustic and thermal performance.
    • Biomarkers of Genotoxic and Reprotoxic Effects after Chemical Exposure. The genotoxic effects due to the respiratory disease of Tuberculosis (TB) patients compared to healthy controls in diploid lymphocyte and haploid sperm cells, after treated with two heterocyclic amines and quercetin in bulk and nano forms

      Anderson, Diana; Gopalan, Rajendran C.; Abdulmwli, Mhamoued A.A. (University of BradfordSchool of Chemistry and Bioscience, 2019)
      In the tuberculosis patients, Mycobacterium tuberculosis can stimulate production of hydrogen peroxide in the host as a result of immune response. The H2O2 accumulate in pulmonary cells, causing oxidative stress that could lead to the cancer. We select TB patients for this study which investigates the effects of quercetin as there is an increased incidence of latent TB among the migrant population in the past few years and TB can increase the risk of cancer. Sperm and lymphocytes were treated with DNA damage inducers and quercetin (10µM, 25µM and 100µM), the responses evaluated using the Comet and micronucleus techniques. The gene expressions of COX1, COX2, P53 and Bcl-2 and catalase protein expression were investigated using the qPCR and Western blot techniques. The results showed that a substantial reduction of DNA damage in lymphocytes from TB patients and sperm from healthy donors from * P ≤ 0.0283 to *** P≤0.001in the Comet assay. In the MNi assay, the effect of quercetin in lymphocytes was more significant in reduce DNA damage, whereas the DNA damage induced by a food mutagen was significant, from *p 0.0405 to ***p 0.001. The qPCR showed significance down-regulation of COX1 and Bcl-2 gene expression, rated between *p 0.045 and **p 0.0074. However, the catalase protein was up-regulated by the nano form of quercetin when using lymphocytes from TB patients and showed significant changes at *p 0.0236. In conclusion, the nano form was found to be more efficient at the reduction of DNA damage in the Comet and micronucleus assays. Also, it down-regulated COX1 and Bcl-2 and up-regulated the catalase proteins indicating a possible role for quercetin, in genoprotection to TB through its enzyme modulating effect.
    • Ethnic differences in sedentary behaviour and physical activity among primary school age children. Towards a movement behaviour intervention for primary school age children

      Horne, Maria; Barber, Sally E.; Mohammed, Mohammed A.; Nagy, Liana C. (University of BradfordFaculty of Health Studies, 2019)
      High levels of sedentary behaviour (SB) and low levels of physical activity (PA) in primary school children are a health concern especially for the South Asians (SA) because of increased cardiovascular risk. The study investigated ethnic differences in movement behaviours among primary school children in three studies: 1) inclinometer and accelerometer measured movement behaviours in White British (WB) vs. SA 6-8-year-old children; 2) qualitative studies with children, parents and teachers explored barriers and facilitators to reducing SB; and, 3) accelerometer measured movement behaviours in children aged 8-11-years. The inclinometer outcomes were: total SB, SB from bouts >30 minutes and breaks in SB, while accelerometry considered: SB, light PA and moderate to-vigorous PA and counts per minute. 525 children, eight parents and six teachers participated. No ethnic differences were identified in inclinometer outcomes except for SB breaks. SA children had 25 fewer breaks compared to WB. Accelerometry identified higher SB for SA children vs. WB in study one but no ethnic differences in study three; a pattern for higher SB/lower PA for SA children vs. WB was consistent in studies. Reasons for engagement in SB included: knowledge and beliefs about SB, child characteristics, cultural norms, parenting, educational system and the built environment. A large proportion of movement behaviour interventions components were related to education and policy. Children’s levels of SB were similar to office workers regardless of ethnicity. Interventions to reduce SB need to consider SB breaks and PA, especially for SA children who were less active and more sedentary than WB.
    • Impaired Wound Healing and Inflammation: The Role of the Dermal Fibroblast. Phenotypic Changes in the Human Dermal Fibroblast with Inflammation; Potential Impact on Wound Healing

      Thornton, M. Julie; Tobin, Desmond J.; Riches-Suman, Kirsten; Al-Rikabi, Aaiad H.A. (University of BradfordFaculty of Life Sciences. Centre of Skin Science, 2019)
      Dermal fibroblasts positively contribute throughout the wounding response by secreting a profile of pro- and anti-inflammatory cytokines in the wound milieu. However, a chronically inflamed environment will, cause detrimental effects on the functional, secretory, and molecular properties of these cells. This study aims to understand how the effect of the pro-inflammatory cytokine TNF-α modulates both healthy and diabetic dermal fibroblast phenotype. To mimic a chronic inflammatory environment and assess whether fibroblasts respond similarly in different anatomical sites, donor-matched fibroblasts from face and scalp were pre-incubated for 3 days with different concentrations (2.5, 25 or 250 ng/ml) of TNF-α. All concentrations significantly impaired proliferation by day 14 in cells from both sites and stimulated (papillary) metabolic activity at day 14. However, this did not correlate with an increase in papillary cell senescence since this did not appear until passage 17, and then only at a supra pathophysiological concentration. Migration of dermal fibroblasts, assessed by the scratch assay. TNF-α significantly inhibited the cells migration, particularly in diabetic fibroblasts, suggesting they are more sensitive to TNF-α. Since TNF-α may stimulate the secretion of soluble paracrine factors by dermal fibroblasts, conditioned medium was collected to assess its effect on other dermal fibroblasts, however, this had no significant effect on migration. However, using gelatin zymography, it was found that TNF-α did stimulate the secretion of soluble paracrine factors that induce MMP activity in non-diabetic fibroblasts, mirroring previous observations that a pro-inflammatory environment can increase proteolytic activity, and indicating that diabetic fibroblasts were again more sensitive than healthy. No difference was observed with MMP-9 activity and nor did the results with dermal fibroblasts reach statistical significance, perhaps because of a relatively low n-number. The ability of TNF-α to modulate the expression of genes associated with the ECM (MMP-1, -2, -9, TIMP-1, and -2) and senescence (Sirt1 and 6) was investigated. There was no change in Sirt1 and Sirt6 expression and no evidence of paracrine effects (conditioned medium) on any of the genes. TNF-α significantly induced mRNA expression of MMP-1 in healthy non-scratched and scratched diabetic fibroblasts, and TIMP-1 in healthy non-scratched cells. There was also considerable donor variability that prevented statistical significance being achieved under the other conditions. The secretion of various cytokines associated with inflammation was compared in healthy and diabetic fibroblasts in the presence and absence of TNF-α. Seven cytokines were secreted, by healthy and diabetic male and female fibroblasts, although diabetic female fibroblasts did not secrete two of them. TNF-α stimulated secretion of cytokines in healthy and diabetic, male and female cells but the profiles of those released were different between the different groups. There was no TNF-α induced paracrine effect on cytokine secretion by healthy dermal fibroblasts. In conclusion, changes in the microenvironment and the influx of pro inflammatory cytokines may significantly alter the dermal fibroblast phenotype. Understanding these functional and molecular changes in response to inflammatory cytokines will give a better understanding of the differences between fibroblast activity in normal physiological wound healing and chronic or diabetic non-healing wounds.
    • Quantum circuit analysis using analytic functions

      Vourdas, Apostolos; Lei, Ci; Abobakr, Mona R.H. (University of BradfordSchool of Electrical Engineering and Computer Science, 2019)
      In this thesis, classical computation is first introduced. Finite quantum systems are considered with D-dimensional Hilbert space, and position x and momentum p taking values in Z(D) (the integers modulo D). An analytic rep resentation of finite quantum systems that use Theta function is presented and considered. The first novel part of this thesis is contribution to study reversible classical CNOT gates and their binary inputs and outputs with reversible cir cuits. Furthermore, a reversible classical Toffoli gates are considered, as well as implementation of a Boolean expression with classical CNOT and Toffoli gates. Reversible circuits with classical CNOT and Toffoli gates are also considered. The second novel part of this thesis the study of quantum computation in terms of CNOT and Toffoli gates. Analytic representations and their zeros are considered, while zeros of the inputs and outputs for quantum CNOT and Toffoli gates are studied. Also, approximate computation of their zeros on the output are calculated. Finally, some quantum circuits are discussed. i
    • Death, disability, and diversity: An investigation of physical impairment and differential mortuary treatment in Anglo-Saxon England

      Buckberry, Jo; Croucher, Karina T.; Bohling, Solange N. (University of BradfordSchool of Archaeological and Forensic Sciences, 2020)
      Until recently, individuals with physical impairment have been overlooked within the field of archaeology due to the controversy surrounding the topics of disability and care in the past. The current research adds to the growing body of archaeological disability studies with an exploration of physical impairment and the possibility of disability-related care in Anglo-Saxon England (5th-11th centuries AD), utilising palaeopathological, funerary, and documentary analyses. Palaeopathological analysis of 86 individuals with physical impairment from 19 Anglo-Saxon cemetery populations (nine early, five middle, and five later) was performed, and the possibility of disability-related care was explored for several individuals. The mortuary treatment data (e.g. grave orientation, body position, grave good inclusion) was gathered for the entire burial population at each site (N=3,646), and the funerary treatment of the individuals with and without physical impairment was compared statistically and qualitatively, both within and between the Anglo-Saxon periods. No obvious mortuary differentiation of individuals with physical impairment was observed, although several patterns were noted. In three early Anglo-Saxon cemeteries, spatial association between individuals with physical impairment, non-adults, and females was observed. Early Anglo-Saxon individuals with physical impairment were more frequently buried in marginal locations, and two such individuals were buried in isolation. In the middle and later Anglo-Saxon periods, the funerary treatment of individuals with physical impairment became less variable, they were less frequently buried in marginal locations, and at three middle Anglo-Saxon cemeteries, they were buried in association with socially significant features in the cemetery landscape. The provision of care to ensure survival was not necessary for a majority of the individuals with physical impairment, but several individuals (lower limb paralysis, mental impairment) may have received regular, long-term care. This research proposes that the decreasing variability of mortuary treatment of individuals with physical impairment observed throughout the Anglo-Saxon period suggests that more variable attitudes about disability existed both within and between early Anglo-Saxon communities, while the political, social, and religious unification starting in the middle Anglo-Saxon period may have led to the development of more standardised perceptions of disability in later Anglo-Saxon England.
    • Assessment of lime-treated clays under different environmental conditions

      Mohamed, Mostafa H.A.; Ali, Hatim F.A. (University of BradfordFaculty of Engineering and Informatics, 2019)
      Natural soils in work-sites are sometimes detrimental to the construction of engineering projects. Problematic soils such as soft and expansive soils are a real source of concern to the long-term stability of structures if care is not taken. Expansive soils could generate immense distress due to their volume change in response to a slight change in their water content. On the other hand, soft soils are characterised by their low shear strength and poor workability. In earthwork, replacing these soils is sometimes economically and sustainably unjustifiable in particular if they can be stabilised to improve their behaviour. Several techniques have evolved to enable construction on problematic soils such as reinforcement using fibre and planar layers and piled reinforced embankments. Chemical treatment using, e.g. lime and/or cement is an alternative method to seize the volume change of swelling clays. The use of lime as a binding agent is becoming a popular method due to its abundant availability and cost-effectiveness. When mixed with swelling clays, lime enhances the mechanical properties, workability and reduces sensitivity to absorption and release of water. There is a consensus in the literature about the primary mechanisms, namely cation exchange, flocculation and pozzolanic reaction, which cause the changes in the soil characteristics after adding lime in the presence of water. The dispute is about whether these mechanisms occur in a sequential or synchronous manner. More precisely, the controversy concerns the formation of cementitious compounds in the pozzolanic reaction, whether it starts directly or after the cation exchange and flocculation are completed. The current study aims to monitor the signs of the formation of such compounds using a geotechnical approach. In this context, the effect of delayed compaction, lime content, mineralogy composition, curing time and environmental temperature on the properties of lime-treated clays were investigated. The compaction, swelling and permeability, and unconfind compression strength tests were chosen to evaluate such effect. In general, the results of the geotechnical approach have been characterised by their scattering. The sources of this dispersion are numerous and include sampling methods, pulverisation degree, mixing times and delay of compaction process, a pre-test temperature and humidity, differences in dry unit weight values, and testing methods. Therefore, in the current study, several precautions have been set to reduce the scattering in the results of such tests so that they can be used efficiently to monitor the evolution in the properties that are directly related to the formation and development of cementitious compounds. Four clays with different mineralogy compositions, covering a wide range of liquid limits, were chosen. The mechanical and hydraulic behaviour of such clays that had been treated by various concentrations of lime up to 25% at two ambient temperatures of 20 and 40oC were monitored for various curing times. The results indicated that the timing of the onset of changes in mechanical and hydraulic properties that are related to the formation of cementitious compounds depends on the mineralogy composition of treated clay and ambient temperature. Moreover, at a given temperature, the continuity of such changes in the characteristics of a given lime-treated clay depends on the lime availability.
    • Dynamic soil-structure interaction of reinforced concrete buried structures under the effect of dynamic loads using soil reinforcement new technologies. Soil-structure interaction of buried rigid and flexible pipes under geogrid-reinforced soil subjected to cyclic loads

      Mohamed, Mostafa H.A.; Sheehan, Therese; Elshesheny, Ahmed (University of BradfordFaculty of Engineering and Informatics University of Bradford, 2019)
      Recent developments in constructions have heightened the need for protecting existing buried infrastructure. New roads and buildings may be constructed over already existing buried infrastructures e.g. buried utility pipes, leading to excessive loads threatening their stability and longevity. Additionally applied loads over water mains led to catastrophic damage, which result in severe damage to the infrastructure surrounding these mains. Therefore, providing protection to these existing buried infrastructure against increased loads due to new constructions is important and necessary. In this research, a solution was proposed and assessed, where the protection concept would be achieved through the inclusion process of geogrid-reinforcing layers in the soil cover above the buried infrastructure. The controlling parameters for the inclusion of geogrid-reinforcing layers was assessed experimentally and numerically. Twenty-three laboratory tests were conducted on buried flexible and rigid pipes under unreinforced and geogrid-reinforced sand beds. All the investigated systems were subjected to incrementally increasing cyclic loading, where the contribution of varying the burial depth of the pipe and the number of the geogrid-reinforcing layers on the overall behaviour of the systems was investigated. To further investigate the contribution of the controlling parameters in the pipe-soil systems performance, thirty-five numerical models were performed using Abaqus software. The contribution of increasing the amplitude of the applied cyclic loading, the number of the geogrid-reinforcing layers, the burial depth of the pipe and the unit-weight of the backfill soil was investigated numerically. The inclusion of the geogrid-reinforcing layers in the investigated pipe-soil systems had a significant influence on decreasing the transferred pressure to the crown of the pipe, generated strains along its crown, invert and spring-line, and its deformation, where reinforcing-layers sustained tensile strains. Concerning rigid pipes, the inclusion of the reinforcing-layers controlled the rebound that occurred in their invert deformation. With respect to the numerical investigation, increasing the number of the reinforcing-layers, the burial depth of the pipe and the unit-weight of the backfill soil had positive effect in decreasing the generated deformations, stresses and strains in the system, until reaching an optimum value for each parameter. Increasing the amplitude of the applied loading profile resulted in remarkable increase in the deformations, stresses and strains generated in the system. Moreover, the location of the maximum tensile strain generated in the soil was varied, as well as the reinforcing-layer, which suffered the maximum tensile strain.
    • Flow Imaging of the Fluid Mechanics of Multilayer Slide Coating. Flow visualisation of layers formation in a 3-layers slide coating die, measurement of their thicknesses and interfacial and free surface flow instabilities

      Benkreira, Hadj; Whiteside, Benjamin R.; Alpin, Richard P. (University of BradfordFaculty of Engineering and Informatics, 2016)
      Coating onto a moving substrate several films simultaneously on top of each other is a challenging exercise. This is due to the fact, depending on operating conditions (thickness and velocity of individual layers and the physical properties of the coating fluids), flow instabilities may arise at the interfaces between the layers and on the top layer. These instabilities ruin the application of the final multi-layered coating and must be avoided. This research addresses this coating flow situation and seeks to develop guidelines to avoid these instabilities. Following a critical literature survey, this thesis presents a novel experimental method that visualises multi-layered coating flow down an inclined multi-slot die. The visualisation is obtained using a unique configuration including a high-speed camera, telecentric objective lens and illumination. The results show for a single layer, as the die angle and Reynolds number increases, the flow becomes more unstable and for a dual layer flow, as Re increases the peak to peak amplitude and the frequency decreases at the free surface and interface. The latter was unexpected and does not conform with existing literature. The triple layer results show either a monotonically increasing or increasing from first to second layer viscosity stratifications are the most stable flows along with flow heights in the first and second layers of <22% and >18% of the total thickness respectively, which concur with current literature. The visualisation additionally obtained other instabilities including single layer back-wetting and vortices, and multilayer slot invasion with the findings concurring with current literature.
    • Distribution Network Operation with High Penetration of Renewable Energy Sources. Joint Active/Reactive Power Procurement: A Market-Based Approach for Operation of Distribution Network

      Mokryani, Geev; Rajamani, Haile S.; Abd-Alhameed, Raed A.; Zubo, Rana H.A. (University of BradfordFaculty of Engineering and Informatics, 2019)
      Distributed generators (DGs) are proposed as a possible solution to supply economic and reliable electricity to customers. It is adapted to overcome the challenges that are characterized by centralized generation such as transmission and distribution losses, high cost of fossil fuels and environmental damage. This work presents the basic principles of integrating renewable DGs in low voltage distribution networks and particularly focuses on the operation of DG installations and their impacts on active and reactive power. In this thesis, a novel technique that applies the stochastic approach for the operation of distribution networks with considering active network management (ANM) schemes and demand response (DR) within a joint active and reactive distribution market environment is proposed. The projected model is maximized based on social welfare (SW) using market-based joint active and reactive optimal power flow (OPF). The intermittent behaviour of renewable sources (such as solar irradiance and wind speed) and the load demands are modelled through Scenario-Tree technique. The distributed network frame is recast using mixed-integer linear programming (MILP) that is solved by using the GAMS software and then the obtained results are being analysed and discussed. In addition, the impact of wind and solar power penetration on the active and reactive distribution locational prices (D-LMPs) within the distribution market environment is explored in terms of the maximization of SW considering the uncertainty related to solar irradiance, wind speed and load demands. Finally, a realistic case study (16-bus UK generic medium voltage distribution system) is used to demonstrate the effectiveness of the proposed method. Results show that ANM schemes and DR integration lead to an increase in the social welfare and total dispatched active and reactive power and consequently decrease in active and reactive D-LMPs.