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Double moral hazard and relational contract : evidence from Ghana and experimental economics
Get PDFPh. D. Thesis.In developing countries, one of the main constraints for the development of value supply
chains is side-selling and payment default by buyers. There is burgeoning literature
examining financial and labour contracts in Sub-Saharan Africa, but less is known about
informal contractual relations between buyers and sellers in agri-food markets. Yet,
agribusiness development in Africa will depend on more stable contractual arrangements
in food value chains. This study has two main aims: the first is to examine attributes of
Ghanaian fresh vegetables supply chain contracts and second, to experimentally investigate
the mitigation of double moral hazard in buyer-seller contracts. The first part of the study
uses a survey method aiming to describe the nature of contracting and the factors
determining contractual breaches by sellers. A logit regression results show that being an
older farmer, distance to alternative market, monitoring and production management
contract significantly increased side-selling while the time of contract price setting, time of
payment, shorter contract relationship, and a farmer being a male positively influenced
side-selling. The second study examines how an institution where buyers commit to a
deposit of the value of payment agreed with the seller may resolve the contract breaches.
This study aligns with the literature on informal and relational contracts, but rather than
relying on repeated interactions and reputation it examines double moral hazard in a single
shot game involving 294 participants. A buyer player proposes a contract price to a seller
for the purchase of a commodity but can reduce the price ex-post. Similarly, the seller can
side-sell the contracted commodity for a spot market price. The results show that fewer
buyers voluntarily committed to a deposit of the payment but doing so resulted in a
significantly less side-selling suggesting reciprocity in the seller’s behaviour. Moreover,
anticipating that buyers may not voluntarily commit to a deposit, an institution that enforces
a commitment to the deposit was examined and shown to further decrease side-selling.Ghana Education Trust Fund (GETFund
Development of proteomics strategies for the characterisation of endosomal TLR2 signalling
Get PDFPh. D. Thesis.Liquid chromatography- mass spectrometry (LC-MS) is a highly sensitive analytical tool which can be instrumental for a wide range of applications, including use in the clinic to identify disease biomarkers in patient samples and in the laboratory to study the changing proteome from cells. Buffers and HPLC methods for protein separation were developed for the analysis of therapeutic monoclonal antibodies (MAbs) and human serum.
For serum analysis, protein separation methods were created using the MAbPac column with 0.02 % SDS added to the mobile phase. Coupled with basic reverse phase (BRp) chromatography, it is possible to identify >1000 proteins not present when BRp is used alone. This method was also applied to the analysis of serum, as an alternative to protein depletion and as a method of increasing the number of identifications of low-abundance disease biomarkers.
Toll-like receptors (TLRs) are one of the most widely studied groups of pathogen recognition receptors. plasma membrane (PM) TLRs initiate the pro-inflammatory cytokine pathway, and endosomal TLRs initiate the transcription of type I interferons (IFNs). An exception is TLR4, which is a PM TLR but is known to translocate to the endosome after activation, initiating the type I IFN transcription pathway. However, recent research suggests that TLR2 could also signal from the endosome.
The proteome of TLR2-activated TLR2 -/- (KO) and Wild-type (WT) cells were analysed by LC-MS/MS. Basal changes in endosomal proteins were found between KO and WT cells and key signalling differences detected upon TLR2 activation, indicating a role for TLR2 in endocytosis, endosomal signalling, and innate immune response.
The proteomes of phagosomes isolated from TLR2 and TLR4 stimulated WT cells were also analysed by LC-MS/MS. TLR2 was observed on the phagosome even in unstimulated cells, indicating that TLR2 is already present on the phagosome under basal conditions. Changes in phagosomal signalling between TLR2 and TLR4 activated cells shows that TLR2 and TLR4 have different roles in endocytosis and phagosomal signalling.
Biochemistry techniques were employed to investigate downstream endosomal TLR2 signalling, revealing that TLR2 initiation of type I IFN occurs via Interferon regulatory factors (IRF) 1 and 7
Socio-spatial analysis of small-area need and accessibility of Primary Healthcare Services in Nigeria: A sequential mixed methods study
Get PDFPh. D. Thesis.Accessibility of primary healthcare (PHC) services is crucial for maintaining the good health of
a population. Not only is health(care) associated with quality of life and socioeconomic
productivity, systematic variations in healthcare accessibility are matters of social justice.
Consequently, the overall goal of this project is to comprehensively analyze and explain smallarea need and accessibility of PHC services in Nigeria through a case study of Kogi State, with
a view to making policy-relevant recommendations. To this end, both quantitative and
qualitative methods are synthesized in an ‘explanatory sequential mixed methods research
design’, which also features innovative data exploitations. This entails a synergy of:
Automated Zone Design method, Spatial Microsimulation Modelling, and Generalized TwoStep Floating Catchment Area method for quantitative analysis as well as qualitative
framework thematic analysis, to obtain research findings that are more robust than existing
studies. In this way, genuine small-area variations in PHC need and accessibility are revealed
and explicated, including extreme Medically Underserved Areas (eMUAs). Urban areas are
more accessible than rural areas, as expected. Of senatorial districts, Kogi Central has the best
healthcare accessibility because of its topography. Furthermore, these variations are
mediated by the extant sub-optimal zoning system in Nigeria, which is a product of
problematic historical political processes. Not only are eMUAs both very remote and rural,
they also lack basic social amenities. Hence, it is not surprising that research participants
expressed a myriad of dire disincentives in meeting their PHC needs. These difficulties can be
mitigated by improving the quality of road infrastructure and ensuring an optimal socio-spatial
configuration of PHC services. Broad mechanisms of social exclusion are also implicated in
causing access-related disutility of PHC. It is therefore crucial that holistic interventions to
alleviate social exclusion are enacted, since previous efforts at addressing only proximal
concerns of PHC accessibility have proven unsuccessful.
Keywords: Primary Healthcare Needs, Spatial Accessibility, Mixed Methods Research,
Automated Zone Design, Spatial Microsimulation, Small-Area Variations.Newcastle University Overseas Research
Scholarship (NUORS), Research Excellence Academy of the Humanities and Social
Science Faculty (HaSS RE
The Pacific self : oceanic narratives and self-representation in accounts of eighteenth-century British voyages of Pacific exploration
Get PDFThis thesis traces the mariner’s oceanic experience in the journals of the voyages of Pacific
exploration made between 1764 and 1780 by John Byron, Samuel Wallis, Philip Carteret and
James Cook and the published narratives that derived from them. Situated within the
emerging field of ‘blue humanities’, the thesis focuses on the account of the ocean and
engages with problems of defining and describing the ocean. It examines how the mariners
articulated their oceanic experience and how their narrative challenged wider cultural
assumptions about the ocean and how it was then absorbed into literary narratives. It argues
that the journals of Pacific exploration increasingly emphasized the experience of being at sea
and, through the adaptation of that narrative in the texts that followed, were part of a larger
shift in the depiction of the ocean.
John Hawkesworth’s official adaptation of the first journals published in 1773 involved a
process of ‘un-seaing’ by which, to suit literary pre-conceptions, the ocean was marginalised
in favour of a renewed focus on landfalls. The adaptations that followed responded to a
variety of audiences. Some continued to ‘un-sea’ the texts and focussed on terrestrial
encounters. These transferred the “other” of the ocean to the societies found there, part of a
developing narrative of colonization. However others, designed to appeal to the more
‘middling-sort’ of reader who might identify with the professionalised accounts the mariners
had provided, reengaged with the maritime narrative of the original journals. Here the
description of the oceanic experience was revitalised. Thus, the thesis argues, the journals
found a place in the literary discourse of the voyage and helped shape a larger understanding
of the ocean that challenged its uncertainty and put the mariner’s oceanic experience at its
centre
Loss Reduction in Axial Flux Machines using Magnetic Shielding
Get PDFPhD ThesisAbstract– The introduction of compacted insulated iron powder in electrical machines design makes their manufacturing process easy together with high rates of production and the machine parts made from it are stable dimensionally compared to conventional laminated steel. The research work presented in this thesis was carried out with the main aim to improve the overall performance of a three-phase Axial Flux Machine (AFM) using Soft Magnetic Composite (SMC). To realise it, the machine was redesigned in a way to benefit from the unique properties of the material such as low eddy current loss at high frequency, isotropic magnetic properties and simple manufacturing process.
Due to the three-dimensional (3D) nature of the SMC material and AFM structure, 3D Finite Element Analysis (FEA) was carried out for accurate prediction of performance and extensive simulation results were provided. Higher fill factor up to 70% was achieve by compacting the pre-formed coils on a bobbin before sliding onto the tooth for final assembly, which offered a significant improvement in performance. AC winding loss analysis was performed due to open-slot stator winding configuration and the higher frequency of operation resulting in skin-depths of the same order of size as the typical conductor diameters. A method of AC winding loss reduction was introduced using a single steel lamination sheet to shield the windings from stray fields due to the open-slot stator construction which encourage an elevated AC loss at AC operation. Moreover, this approach is easy to implement for this machine topology and does not require the use of more complex twisted and Litz type conductors.
To validate the 3D FEA, a prototype machine was built which ultimately resulted in 6 machines being tested without and with steel lamination sheet during this PhD. The measured result which includes the back EMF, full load voltage, torque, power and losses are thoroughly presented and agreed with the 3D FEA very well. Depending on lamination type, it is shown that the AC winding loss reduced by up to 48.0%, total loss reduced by up to 31.7%, this method has disadvantages of minor reduction of up to 3.5%, 5.8% and 2.8% in the peak back EMF, torque and output power respectively. The efficiency has increased by up to 10.3%.
The research studies signify the viability of designing and producing a highly efficient AFM with SMC and has the potential for mass production, this thesis makes significant contribution by implementing a simple novel method for AC winding loss reduction using steel lamination sheet to shield the stray flux due to open-slot stator winding construction.The Petroleum Technology Development Fund (PTDF) Nigeria and NASRDA-CBS
An exploration of the life course determinants of oral health in the United Kingdom
Get PDFPh. D. Thesis.Poor oral health has a substantial impact at both an individual and societal level and
develops across the life course. This research explored the life course determinants of oral
health in the UK, addressing an existing lack of research in this field.
This mixed-methods research utilised an existing longitudinal prospective birth cohort study
– the Newcastle Thousand Families Study – which recruited 1,142 babies born in Newcastle
upon Tyne in 1947. Twenty in-depth interviews were conducted with participants at age 67,
to explore what influenced how they looked after their oral health across the life course.
The broader life course determinants of age 63 tooth retention in this cohort were
subsequently modelled using path analysis techniques.
The interviews revealed that a range of factors influenced oral health behaviours, centring
around four sources: the dental profession, wider society (e.g. schools, peers, the media),
family members and the individuals themselves. Determinants varied to some extent
between different behaviours and also across the life course. Parents were reportedly the
predominant influencers in childhood, whilst individual-level and peer influences played a
major role during the transition to independent adulthood. Throughout independent
adulthood, influences were diverse, although, notably, family influences transferred from
parents to spouses and children, especially the former.
The path analysis demonstrated that multiple factors across the life course influenced age 63
tooth retention, including smoking and dental attendance, socio-economic determinants,
dental anxiety, sex and parental encouragement. However, the potential influence of
unmeasured factors (specifically sugar consumption) could not be established due to data
limitations.
Subject to potential differences between this 1947 cohort and contemporary generations,
this research suggests that oral health interventions should target an array of behavioural,
social and psychological factors at the level of individuals, families, society and the dental
profession, prioritising the most appropriate determinants at each life course stage.National Institute for Health Research (NIHR
A Lipopolysaccharide (LPS) inhalation model to characterise divergent innate cellular responses and presence of alveolar leak, early in the course of acute lung inflammation
Get PDFM. D. Thesis.Acute respiratory distress syndrome (ARDS) is a common condition presenting to the intensive care unit (ICU) and is associated with high morbidity and mortality. Experimental models in humans using bacterial lipopolysaccharide (LPS, delivered by nebulised inhalation or bronchial instillation) create reproducible acute lung inflammation and can be used to model early stages of the pathological process leading to ARDS. A significant body of evidence already exists from animal and human studies suggesting LPS inhalation results in rapid release of pro-inflammatory cytokines and movement of innate immune cells (neutrophils and monocytes) into the alveolar space. The functional status of neutrophils in response to this stimulus is largely unknown, based on circumstantial evidence provided by predominant cytokines, chemokines and cell surface protein expression. Most studies rely on invasive assessment of the alveolar space using bronchoalveolar lavage (BAL), and imaging modalities have been poorly explored in LPS respiratory models.
This thesis aimed to test the hypothesis that, following inhalation of LPS, neutrophils circulating within peripheral blood increase their capacity for phagocytosis and generation of reactive oxygen species (ROS), and that dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) detects early increases in pulmonary vascular permeability.
Forty-nine healthy human volunteers were recruited to an LPS inhalation study. Volunteers underwent inhalation of 60μg of LPS or Saline via a nebuliser dosimeter, with peripheral blood sampling. A subset underwent DCE MRI scans and bronchoscopy with BAL. Functional assays of phagocytosis and respiratory burst activity were performed on isolated neutrophils from blood.
Neutrophils demonstrated a trend towards increased phagocytosis following LPS inhalation (change from baseline of 3.6% versus 1.2% in control subjects, p=0.058). This was not supported by any change in respiratory burst activity or flow cytometry assessment of cell surface protein expression. Analysis of DCE MRI of the lungs proved difficult and was complicated by significant artefact from surrounding structures and respiratory motion.
In conclusion, LPS inhalation did not significantly affect phagocytosis or respiratory burst activity of neutrophils in the systemic circulation. DCE MRI was unable to detect changes in vascular permeability following LPS inhalation above the background noise
A decision-making tool for real-time prediction of dynamic positioning reliability index
Get PDFPhD ThesisThe Dynamic Positioning (DP) System is a complex system with significant levels of
integration between many sub-systems to perform diverse control functions. The extent of
information managed by each sub-system is enormous. The sophisticated level of integration
between sub-systems creates an array of possible failure scenarios. A systematic analysis of all
failure scenarios would be time-consuming and for an operator to handle any such catastrophic
situation is hugely demanding. There are many accidents where a failure in a DP system has
resulted in fatalities and environmental pollution. Therefore, the reliability assessment of a DP
system is critical for safe and efficient operation. The existing methods are time-consuming,
involving a lot of human effort which imposes built-in uncertainty and risk in the system during
complex operation.
This thesis has proposed a framework for a state-of-the-art decision-making tool to assist an
operator and prevent incidents by introducing a new concept of Dynamic Positioning –
Reliability Index (DP-RI). The DP-RI concept covers three phases, leading to technical
suggestions for the operator during complex operations, which are defined as Data,
Knowledge, Intelligence, and Action. The proposed framework covers analytics including
descriptive, diagnostic, predictive and prescriptive analytics. The first phase of the research
involves descriptive and diagnostic analytics by performing big data analytics on the available
databases to identify the sub-systems which play critical roles in DP system functionality. The
second phase of the research involves a novel approach where predictive analytics are used for
the weight assignment of the sub-systems, dynamic reliability modelling and offline and realtime forecasting of DP-RI. The third phase introduces innovative prescriptive analytics to
provide possible technical solutions to the operator in a short time during failures in the system
to enable them to respond quickly and prevent DP incidents. Thus, the DP-RI acts as an
innovative state-of-the-art decision-making tool which can suggest possible solutions to the
DPO by using analytics on the knowledge database. The results proved that it is a useful tool
if implemented on an actual vessel with diligent integration with the DP control system.Singapore Economic Development Board (EDB) and DNV
GL Singapore Pte Ltd
Integrated design approach for responsive solar-shadings in double skin facades in hot arid climate
Get PDFPh. D. Thesis.To deliver climate adaptive architecture, current trends in architecture are directed
towards dynamic and responsive building skins. ‘Responsive building skin’ is used to describe
the ability of building envelopes to adapt in real time in response to external environmental
conditions. Recent attention has focused on ‘soft robotics’ approach which uses soft and/or
extensible materials to deform with muscle‐like actuation, mimicking biological systems.
Material embedded actuation can autonomously alter shading systems’ morphology
stimulated by external environmental conditions. Passively thermally‐activated shading
systems offer responsive actuation by solar‐radiation and stratified hot air in a double skin
façade (DSF) without recourse to energy consuming systems.
This research identifies the intersection between bio‐inspiration, folding principles and
smart materials to integrate the underlying mechanisms in responsive solar‐shading systems
and assesses their environmental performance. The thesis proposes an interdisciplinary mixed
methodology linking hands‐on experimentation with environmental performance simulation
of responsive building skins. ‘Practice‐led approach’ is used to explore the design potential of
responsive systems using smart materials. ‘Computational Fluid Dynamics’ (CFD) numerical
methods are used to measure the impact of responsive solar‐shading systems on multiple
environmental factors in a DSF cavity. This helps the design decisions, selection and
customisation of smart materials. Hands‐on experimentation is used to explore various
prototypes, leading to the selection of a folded prototype, to be simulated for environmental
performance. Solar‐shading systems are tested within a DSF, in an hot arid climate. Flat and
folded solar‐shading devices are installed in a DSF cavity with three aperture sizes (30%, 50%
& 70%) to represent the responsive system states. Point‐in‐time simulations are carried at
9:00 am, 12:00 pm and 15:00 pm in peak summer and winter day.
The developed analytical design framework presents different design parameters for
responsive solar‐shading systems to guide decision‐making in research of climate actuated
smart shading systems.
Keywords: Responsive skins, Adaptive facades, Soft robotics, Bio‐inspiration, Origami,
Deployable structures, Actuation, Smart materials, Shape memory alloys, Double skin facades,
Energy efficiency, Digital simulation, CFD Modelling
Increasing the torque density of an in-wheel automotive traction motor
Get PDFPh. D. Thesis.In-wheel electric motors have been developed in recent years to provide integrated direct drive
traction in electric vehicles. Classical automotive components, including drive shafts, gears and
differentials can be eliminated by integrating the drive and the motor in the wheel. Researching
in-wheel motors is therefore part of the drive towards efficient electric vehicles. This thesis is
concerned with improving the torque performance of an existing radial flux in-wheel electric
motor.
This work studies alternative motor topologies, which could provide improved torque density
as compared with the existing motor design. Firstly three-dimensional flux machines are
investigated, specifically the transverse flux machine. Two different configurations are shown to
deliver higher torques than the radial flux machine in continuous operation but have failed to
deliver the required overload torque. In addition, low power factor and low efficiency is shown
to make these machines unsuitable for the application of in-wheel traction motor.
Secondly, increase in torque production was researched by investigating the exploitation of
saliency in conventional radial flux machines. The use of distributed windings and interior
permanent magnets allowed an increase in the salient torque of the machine. However, the
available volume is shown to be too small for an interior permanent magnet topology. Salient
machines will be better suited for high-power high-speed applications using a mechanical gearbox
for torque transfer.
The majority of the work relates to the third topology studied which incorporates Halbach
arrays. The use of a Halbach array in the rotor allows a reduction in the rotor core back and
gives an increase in the torque capability of the machine. Demagnetisation can be solved by
reshaping the pole and transition magnets. Moving from a parallel slot to a parallel teeth stator
configuration allows a reduction of the stator saturation and thus increases the amount of flux that
the machine can handle in an overload condition, improving continuous and transient overload
torque capability. In addition, AC copper losses are reduced in the parallel teeth topology.
Overall, it is shown that a higher torque density and efficiency can be achieved by adopting a
Halbach array rotor with parallel teeth.
A Halbach array rotor was manufactured and tested, validating the simulations. The manufacturing
feasibility was studied, using different tests and assembly tools. Compared to the pre-existing
design, this manufactured motor is shown to give an increase of 7% torque during continuous
operation and 9% on the overload condition. In addition, efficiency at required operational points
was increased by up to a 3%.Protean Electri