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Co- and Post-seismic Deformation of the 1999 Chi-Chi Earthquake Revealed by Earth Observations
Get PDFPh. D. ThesisThe Mw 7.6 Chi-Chi earthquake struck Central Western Taiwan in 1999. The
rupture was complex with several dislocations along the 100-km long Chelungpu
thrust fault. Revisiting this earthquake is a challenge, as the precision and coverage
of the Earth observations available are quite poor, but it allows better understanding
of regional fault properties. Furthermore, the topographic and vegetation coverage
complexity of the area prevents coherent radar images. In this thesis, radar and
optical images, and terrestrial geodetic measurements, were utilised to study the
Chelungpu fault and more specifically the impact of the Chi-Chi earthquake.
First, five types of Earth observations were processed to investigate the co-seismic
deformation. The Particle Swarm Optimization and Okada Inversion (PSOKINV)
geodetic inversion package was used with the generalized Akaike’s Bayesian Information
Criterion (gABIC) to precisely determine the coseismic slip distribution and
relative weighting of datasets. Differences in results using the data sets jointly or
separately (e.g., under-estimation due to InSAR, inconsistencies in SPOT offsets,
smoother slip distribution with gABIC weighting) are observable. Most of the energy
was released in the northern part of the fault, where the strike veers toward
the east, and mainly at depths of less than 4 km. The PSOKINV-gABIC approach
is viable for the study of complicated cases such as the Chi-Chi earthquake (complex
fault geometry and multi-source observations) and can substantially benefit the
weight determination and physical (no overlap or gap) realism of the fault geometry.
Second, the post-seismic deformation of this event was observed using 20 years
of time series from InSAR and GPS. Then, a model of the afterslip and viscoelastic
relaxation was built. 11 years of ERS, 3 years of EnviSAT, 6 years of Sentinel-1A/B
descending and 3 years of Sentinel-1A/B ascending images were processed using
GAMMA-Remote Sensing software and atmospherically corrected using GACOS
(Generic Atmospheric Correction Online Service for InSAR). Finally, InSAR time
series were extracted and validated using GPS data. The modelling of the postseismic
deformation following the Chi-Chi earthquake was done using a power-law
Burgers rheology to analyse the interplay between afterslip and viscoelastic flow.
From the time series, a change in the ground displacement can be observed in 2004
showing a slow-down of afterslip deformation. The forward modelling of the postseismic
deformation showed that the maximum afterslip is observed on the southern
part of the fault, on the decollement in depth (while the maximum slip was happening
at shallow depth on the north section of the fault during the co-seismic
deformation). Furthermore, the study of the strain enabled me to conclude that the
interseismic phase has started over most of the area, most segments of the Chelungpu
fault are now getting locked again. More data coverage and a longer monitoring of
the Chelungpu fault will be needed to observe the entire earthquake cycleESA, UK NER
Soil-structure interaction of a on-shore wind turbine from long term cyclic loading
Get PDFPhD ThesisOnshore wind turbines are very tall and slender structures that often have shallow foundations.
This type of structure is prone to rocking under applied cyclic loading and must withstand
millions of cycles over a 20 year design life from the wind and rotation of the blades. Wind
loading is complex and highly variable in frequency and magnitude, with storm events causing
large increases of horizontal load. In addition to rocking, uplift often occurs under these larger
design loads.
A prototype wind turbine was designed for numerical and experimental modelling to
investigate the behaviour of an onshore wind turbine with shallow foundations in a slightly
overconsolidated kaolin soil, subject to cyclic loading at varying wind speeds. The loading
patterns applied were designed to model normal operation of the turbine interspersed with
storm events. This allowed investigation of the performance of the structure during and after
periods of rocking and uplift. The model was considered to be a two-dimensional (2D) scenario,
as the cyclic loading was applied in one plane only.
The experimental modelling was conducted at the University of Dundee, with five cyclic
tests conducted at 1g and one cyclic test at 50g in the 3m beam geotechnical centrifuge.
The experimental modelling presented three main behavioural characterised determined from
the reaction of the structure, describing changes in the force reaction, foundation profile and
foundation-soil contact. The three main behaviours are amplification, constant and recovery,
these behaviours express the long term behaviour of the soil-structure interaction and the
ability for the structure to regain strength after large cyclic events.
The soil-structure interaction was shown to change though recording of the natural frequency
of the structure. The natural frequency decreased in all 1g tests, displaying a softening of the
soil structure interaction.
Numerical modelling was carried out using 2D finite element analysis in which the soil
response was described by the Modified Cam-Clay constitutive model, calibrated using data
from experimental testing. The numerical simulations captured many of the mechanisms
governing the response of the turbine and allowed for prediction and visual representation of
the accumulated deviatoric strain and displacement in the soil body.
The findings presented in this thesis show that on-shore wind turbines foundations can be
slightly under designed using less resources. Where current practices see foundation uplift as a
failure of the design, it can be used as structural protection against cyclic loads that can cause
structural degradation
Organising the Implementation of Industry 4.0 in a High Value German Manufacturing Firm: A Complex Adaptive Systems Approach.
Get PDFPh. D. ThesisThis thesis addresses an important research gap in empirical qualitative evidence regarding the organisational aspects of the implementation of Industry 4.0. Whereas there is a basic understanding of the technical implementation in the factory plant, the understanding of the implementation from an organisational perspective is limited. A holistic single case study with 35 semi-structured expert interviews enabled a deep exploration of an implementation in a real-world context at the firm level. The findings demonstrate how a high value German manufacturing company has implemented Industry 4.0, as well as why this firm implemented as it did. Several elements are thematically analysed, representing important examples of how manufacturing firms can organise the implementation of Industry 4.0 in praxis. Covering the three areas of actions, influences and relationships, the implications of the analysed elements are discussed in relation to six theoretical themes, namely centralisation vs. decentralisation, diffusion of new ideas, working in teams, trust, open innovation and path dependence. This thesis represents the first existing study that understands the implementation of Industry 4.0 as a Complex Adaptive System of interrelated system elements which continuously evolve over time. In this sense, a newly developed system model acknowledges important relationship characteristics that lead to a more comprehensive perspective on the complex implementation of Industry 4.0. This thesis contributes to the research field by being the first study to suggest a “dual approach” encompassing important decentralised as well as centralised implementation patterns for a successful process. It furthermore demonstrates how workforce concerns regarding job security significantly influence the emergence of system elements regarding change management during the implementation of Industry 4.0. The thesis offers academic contributions to the Industry 4.0 implementation literature, as well as organisational elements recommended for practitioners when organising the implementation of Industry 4.0
Applications of Non-Orthogonal Waveforms and Artificial Neural Networks in Wireless Vehicular Communications
Get PDFPh. D. ThesisWe live in an ever increasing world of connectivity. The need for highly robust,
highly efficient wireless communication has never been greater. As we seek to squeeze
better and better performance from our systems, we must remember; even though
our computing devices are increasing in power and efficiency, our wireless spectrum
remains limited.
Recently there has been an increasing trend towards the implementation of machine
learning based systems in wireless communications. By taking advantage of a neural
networks powerful non-linear computational capability, communication systems have
been shown to achieve reliable error free transmission over even the most dispersive of
channels. Furthermore, in an attempt to make better use of the available spectrum,
more spectrally efficient physical layer waveforms are gathering attention that trade
increased interference for lower bandwidth requirements. In this thesis, the performance
of neural networks that utilise spectrally efficient waveforms within harsh transmission
environments are assessed.
Firstly, we investigate and generate a novel neural network for use within a standards
compliant vehicular network for vehicle-to-vehicle communication, and assess its
performance practically in several of the harshest recorded empirical channel models using
a hardware-in-the-loop testing methodology. The results demonstrate the strength
of the proposed receiver, achieving a bit-error rate below 10−3 at a signal-to-noise ratio
(SNR) of 6dB.
Secondly, this is then further extended to utilise spectrally efficient frequency
division multiplexing (SEFDM), where we note a break away from the 802.11p vehicular
communication standard in exchange for a more efficient use of the available spectrum
that can then be utilised to service more users or achieve a higher data throughput.
It is demonstrated that the proposed neural network system is able to act as a joint
channel equaliser and symbol receiver with bandwidth compression of up to 60%
when compared to orthogonal frequency division multiplexing (OFDM). The effect
of overfitting to the training environment is also tested, and the proposed system is shown to generalise well to unseen vehicular environments with no notable impact on
the bit-error rate performance.
Thirdly, methods for generating inputs and outputs of neural networks from complex
constellation points are investigated, and it is reasoned that creating ‘split complex’
neural networks should not be preferred over ‘contatenated complex’ neural networks
in most settings. A new and novel loss function, namely error vector magnitude (EVM)
loss, is then created for the purposes of training neural networks in a communications
setting that tightly couples the objective function of a neural network during training to
the performance metrics of transmission when deployed practically. This loss function
is used to train neural networks in complex environments and is then compared to
popular methods from the literature where it is demonstrated that EVM loss translates
better into practical applications. It achieved the lowest EVM error, thus bit-error
rate, across all experiments by a margin of 3dB when compared to its closest achieving
alternative. The results continue and show how in the experiment EVM loss was able
to improve spectral efficiency by 67% over the baseline without affecting performance.
Finally, neural networks combined with the new EVM loss function are further
tested in wider communication settings such as visible light communication (VLC) to
validate the efficacy and flexibility of the proposed system. The results show that neural
networks are capable of overcoming significant challenges in wireless environments, and
when paired with efficient physical layer waveforms like SEFDM and an appropriate
loss function such as EVM loss are able to make good use of a congested spectrum.
The authors demonstrated for the first time in practical experimentation with SEFDM
that spectral efficiency gains of up to 50% are achievable, and that previous SEFDM
limitations from the literature with regards to number of subcarriers and size of the
transmit constellation are alleviated via the use of neural networksEPSRC, Newcastle Universit
Methodology for managing shipbuilding projectby integrated optimality
Get PDFPhD ThesisSmall to medium shipyards in developing shipbuilding countries face a
persistent challenge to contain project cost and deadline due mainly to the
ongoing development in facility and assorted product types. A methodology
has been proposed to optimize project activities at the global level of project
planning based on strength of dependencies between activities and
subsequent production units at the local level. To achieve an optimal
performance for enhanced competitiveness, both the global and local level of
shipbuilding processes must be addressed. This integrated optimization
model first uses Dependency Structure Matrix (DSM) to derive an optimal
sequence of project activities based on Triangularization algorithm. Once
optimality of project activities in the global level is realized then further
optimization is applied to the local levels, which are the corresponding
production processes of already optimized project activities. A robust
optimization tool, Response Surface Method (RSM), is applied to ascertain
optimum setting of various factors and resources at the production activities.
Data from a South Asian shipyard has been applied to validate the fitness of
the proposed method. Project data and computer simulated data are
combined to carry out experiments according to the suggested layout of
Design of Experiments (DOE). With the application of this model, it is possible
to study the bottleneck dynamics of the production process. An optimum
output of the yard, thus, may be achieved by the integrated optimization of
project activities and corresponding production processes with respect to
resource allocation. Therefore, this research may have a useful significance
towards the improvement in shipbuilding project management
Optimising associations of arbuscular mycorrhizal fungi with wheat
Get PDFPhD ThesisArbuscular mycorrhizal fungi (AMF) are ubiquitous symbionts of most vascular plants and
essential contributors to soil health for which reason their application in agriculture has been
investigated extensively. In wheat as one of the staple foods where large amounts of fertiliser
and pesticides are used, the integration of mycorrhizal benefits such as increased nutrient uptake
and plant health is desirable, but mutualistic outcomes of the symbiosis are determined by
variety, agronomic management practices as well as nitrogen (N) and phosphorus (P) content
of the soil. The present study investigated the impact of different fertiliser sources (biogas
digestate, farmyard manure and mineral N) on AMF at five key development stages of two
wheat varieties (Aszita and Skyfall) +/- crop protection over two cropping seasons 2017-18 and
2018-19 in a P-depleted soil. Additionally, the effect of a commercial AMF inoculum (INOQ
Advantage) on plant performance, yield and grain quality was assessed. AMF-root colonisation
(AMF-RC) was consistently higher in the modern variety Skyfall which also showed lower
abundances of native AMF in response to AMF inoculation. Biogas digestate and farmyard
manure application decreased AMF-RC in both years, whereas mineral N only reduced AMFRC when soil N was high in the first season following grass-clover, but not in the second season
following wheat (i.e. 2nd wheat crop). Amplicon sequencing of the ITS1-region revealed that
mycorrhizal communities in roots were dominated by Glomus spp. and were not affected by
agronomic management or variety. Differential abundance analyses based on sequences of the
small subunit (SSU) however indicated increased diversity of fine root endopyhtes (FRE) in
response to mineral N. Although the AMF inoculum was not detected in roots using strainspecific primers in digital droplet PCR, inoculation with AMF increased biomass production of
wheat without fertiliser and decreased biomass production with mineral N treatment, but these
changes did not affect grain yields. A pot experiment that tested a cellulose-based seed coating
with the INOQ Advantage root powder showed negative effects on plant growth, but without
root colonisation. The results of this study imply a key role of N that impacts AMF-RC, FRE
and the effect of biostimulants. The use of such in wheat production requires further
optimisation to guarantee economic benefit for farmers while excluding side-effects of
exogenous strains on native AMF.Marie Skłodowska-Curie research programme of the
European Union
Reconstructing Early Cypriot Metallurgy : the Case of Pyrgos-Mavroraki
Get PDFPh. D. Thesis.Due to the extraordinary wealth of its ore deposits, Cyprus was the metal powerhouse of
antiquity. The importance of Cypriot ore-mineral deposits has led to a wealth of research on
prehistoric copper mining and production. However, this has overwhelmingly concentrated on
provenance and exchange studies (via the isotopic fingerprinting of ores and ingots) at the
expense of other research strands. In particular, important questions regarding Cypriot copper
technology including the role and identity of bronzesmiths still await full investigation.
Among the few cases of Early-Middle Bronze Age sites which show metallurgical evidence,
Pyrgos-Mavroraki (Limassol) an early 2nd millennium BC settlement site, excavated by the
Italian National Research Council (CNR) from 1998-2012, is certainly the richest known so
far.
The excavations unearthed a vast architectural complex, which hosted several workshops
including an olive press, but most importantly, the complex yielded a great deal of
metallurgical installations and residues.
This research, through a combination of archaeological, analytical and experimental work,
including SEM-EDX slag analysis and on-field copper smelting trials, allowed to reconstruct
the smelting process used at Pyrgos. The archeological evidence shows that Pyrgos’s
metallurgists used a rather primitive smelting technique, involving the use of simple bowlshaped furnaces, small crucibles and blowpipe equipped with simple clay nozzles. However,
despite the high viscosity of the slags obtained did not allow a complete separation of the
metallic copper, the slag-analysis proved that Pyrgos’s coppersmith were capable to smelt
sulfidic ores, which are known to require a multiphase smelting process.Newcastle University, Northern Bridge Consortiu
Optimal scheduling of Distributed Energy Resources connected to Electricity Distribution Networks using Robust Mixed-Integer Second Order Cone Programming
Get PDFEng. D. Thesis.Tackling climate change is a global emergency, driving the electricity sector to
go through rapid changes, including the increasing reliance on local generating
assets, called distributed energy resources (DER). DER range from onsite energy
storage systems, to gas or diesel generators, and renewable generators, but could
also include other forms of generation such as electric vehicles with vehicle-to-grid
capabilities. This PhD proposes a model to optimally schedule DER connected
to radial distribution networks, which can form an active distribution network or a
microgrid, aiming at delivering improvements in operational cost, security of supply
and environmental sustainability. This is mathematically formulated using robust
mixed-integer second-order cone programming. The proposed model takes into
account an accurate power flow model for radial networks and a robust approach
to deal with uncertainty in the market price, the electricity demand, the renewable
generation, and the time and duration of a scheduled interruption from the main grid
when DER form part of a microgrid. Computational experiments support the suitability
of the proposed model, in a number of case studies informed by real-world data
and operational scenarios. This research concludes the following. Firstly, that it is
important to account for detailed modelling of network losses in operational decisions
of such systems, as they profoundly affect both the cost and the network’s operating
state and conditions. Secondly, that the robust approach used in this thesis in order to
deal with uncertainty allows distribution system and/or microgrid operators to manage
trade-offs between the level of the aforementioned uncertainties they are willing to
tolerate, and the operational cost of network assets. Benefits of using the proposed
model include, reduction of the operational cost, and mitigation of technical constraint
violations in actual conditions. The proposed model can be used by a range of
stakeholders including, microgrid operators, distribution system operators, and DER
owners.Newcastle University, Engineering and
Physical Sciences Research Council (EPSRC
Designing sustainable community interfaces
No full textPh. D. Thesis.This thesis explores the role of systems and processes to support inter-community
communication and relations between communities and public service institutions. I explore
two contexts, rural and urban, and the potential of technical systems to support communities
organise, but also support better understanding and dialogues between services providers and
beneficiaries. This potential depends on the contextual barriers and opportunities and the
willingness of stakeholders to adopt systems and processes that inevitably effects change in
day-to-day organisational cultures. Drawing from two longitudinal case studies in the NorthEast of England, I describe the requirements of these systems to be used effectively and
sustainably by communities and public service institutions. The first case study developed with
rural communities of Wooler and Rothbury where, over the course of three years, a communityrun pervasive display network was designed and deployed to bolster intra-community
communication. I describe the development of a partnership with Glendale Gateway Trust and
the design and deployment of simple hardware and bespoke software packaged alongside a
suggested approach for its administration and governance. The study explores the implications
of incorporating a governance model with particular focus on how this impacts ownership,
moderation and maintenance as part of sustaining technical systems between self-organised
configurations of communities. The second case study, developed with Northumbria Police’s
Neighbourhood Policing team, involved the iterative design, implementation and evaluation of
an approach to support police officers communicate more effectively with local communities
and better understand local issues. The intervention aimed to strengthen communityinstitutional relations; it included training neighbourhood police officers in alternative modes
of community engagement and ways to configure technical processes for public institutions’
specific needs and challenges. Learning from these two case studies is synthesized in a
discussion of the different ways technical systems and processes can be designed and
configured to meet stakeholders’ needs and organisational cultures; and to embody important
values such as sustainability, scalability, moderation, governance and ownership
Investigation of wireless power transfer-based eddy current non-destructive testing and evaluation
Get PDFPhD ThesisEddy current testing (ECT) is a non-contact inspection widely used as non-destructive
testing and evaluation (NDT&E) of pipeline and rail lines due to its high sensitivity to surface
and subsurface defects, cheap operating cost, tolerance to harsh environments, and capability
of a customisable probe for complex geometric surfaces. However, the remote field of
transmitter-receiver (Tx-Rx) ECT depends on the Tx-Rx coils gap, orientation, and lift-off
distance, despite each coil responding to the effect of sample parameters according to its liftoff distance. They bring challenges to accurate defect detection and characterisation by
weakening the ECT probe’s transfer response, affecting sensitivity to the defect, distorting the
amplitude of the extracted features, and responding with fewer feature points at non-efficient
energy transfer. Therefore, this study proposed a magnetically-coupled resonant wireless power
transfer (WPT)-based ECT (WPTECT) concept to build the relationship between Tx-Rx coil at
maximum energy transfer response, including shifting and splitting (resonance) frequency
behaviour.
The proposed WPTECT system was investigated in three different studies viz., (1)
investigated the multiple resonance point features for detection and characterisation of slots on
two different aluminium samples using a series-series (SS) topology of WPTECT; (2) mapped
and scanned pipeline with a natural dent defect using a flexible printed coil (FPC) array probe
based on the parallel-parallel (PP) topology of WPTECT; and (3) evaluated five different
WPTECT topologies for optimal response and extracted features and characterised entire
parameters of inclined angular Rolling Contact Fatigue (RCF) cracks in a rail-line material via
an optimised topology. Multiple feature extraction, selection, and fusion were evaluated for the
defect profile and compared in the study, unattainable by other ECT methods.
The first study's contribution investigated multiple resonances and principal component
analysis (PCA) features of the transfer response from scanning (eight) slots on two aluminium
samples. The results have shown the potential of the multiple features for slot depth and width
characterisation and demonstrated that the eddy-current density is highest at two points
proportionate to the slot width. The second study's contribution provided a larger area scanning
capability in a single probe amenable to complex geometrical structures like curvature surfaces.
Among the extracted individual and fused features for defect reconstruction, the multi-layer
feed-forward Deep learning-based multiple feature fusion has better 3D defect reconstruction,
whilst the second resonances feature provided better local information than the first one for
investigating pipeline dent area. The third study's contribution optimised WPTECT topology
for multiple feature points capability and its optimal features extraction at the desired lift-off
conditions. The PP and combined PP and SS (PS-PS) WPTECT topologies responded with
multiple resonances compared to the other three topologies, with single resonance, under the
same experimental situation. However, the extracted features from PS-PS topology provided
the lowest sensitivity to lift-off distances and reconstructed depth, width, and inclined angle of
RCF cracks with a maximum correlation, R2
-value of 96.4%, 93.1%, and 79.1%, respectively,
and root-mean-square-error of 0.05mm, 0.08mm, and 6.60
, respectively.
The demonstrated magnetically-coupled resonant WPTECT Tx-Rx probe characterised
defects in oil and gas pipelines and rail lines through multiple features for multiple parameters
information. Further work can investigate the phase of the transfer response as expected to offer
robust features for material characterisation. The WPTECT system can be miniaturised using
WPT IC chips as portable systems to characterise multiple layers parameters. It can further
evaluate the thickness and gap between two concentric conductive tubes; pressure tube
encircled by calandria tube in nuclear reactor fuel channels.PTDF Nigeri