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Spatial and temporal moisture movement within surface-zone concrete under simulated hot climatic conditions
Get PDFThe ambient environment has a significant influence on the permeation properties of the
surface and near-surface zone of concrete (i.e. the cover zone). Monitoring the water
transport properties within this region is crucial in evaluating the long-term concrete
performance for a particular exposure condition.
This research presents an experimental study of water and moisture transport within the
surface region of concrete samples with and without supplementary cementitious
materials. The samples were conditioned under two regimes representing poor and good
curing; the samples were then exposed to a simulated hot environment with a diurnal
temperature fluctuation of 20–40°C and 60% ambient relative humidity, which was
represented by ambient conditions of North Africa.
Water diffusivity (D) is a fundamental hydraulic property that is important to
characterise water transport of unsaturated concrete. However, its evaluation is
complicated, time-consuming and involves expensive equipment. Therefore, in addition
to monitoring the water movement into concrete, this study also presents initial
developments in application of discretized electrical conductivity measurements as a
relatively simple and low-cost technique to evaluate the water diffusivity of concrete
(D).
Moisture movement within the surface region was monitored using discretised electrical
conductivity measurements, which, together with gravimetric measurements, allowed
evaluation of the volumetric uptake and sorptivity of the concrete and the rate and depth
of water penetration into the concrete cover zone; it is shown that when these are
combined, the degree of saturation, effective porosity and total porosity of the surface
region could be estimated. Electrical measurement, taken at discrete depths from the
exposed concrete surface, showed that, during absorption, the penetration of water into
concrete could be modelled by a sigmoidal function. The results also showed that the
convective zone could be estimated by evaluating the electrical conductivity profile
through the surface zone prior to and after water absorption
Identification and characterisation of novel small-molecule activators of EPAC1
Get PDFEPAC1 is a cyclic AMP sensor protein involved in a multitude of physiological and
pathophysiological processes in the human body and has been recognised as an attractive
target for pharmacological regulation. Activation of EPAC1 protein was reported to
suppress chronic vascular inflammation, making it a potential therapeutic strategy for the
prevention and treatment of cardiovascular disease. While literature describes a range of
EPAC1 inhibitors, no selective small-molecule activators of this protein have been
reported until the 2017 discovery of the N-acylsulphonamide derivative, I942, in the
Yarwood laboratory. The presented study follows up on this finding and aims to identify
novel EPAC1 ligands with agonist properties. A two-phase screening approach was
employed to detect EPAC1-binding compounds with potential agonist component in a
carefully designed library of I942 analogues. Hits from the screen were further analysed
in terms of activity, EPAC1-selectivity, and cytotoxicity, using in vitro biochemical
assays and cell-based tests, alongside another new class of EPAC1 activators identified
in the Yarwood laboratory, benzofuran oxoacetic acid derivatives. In addition to that, the
mechanism of ligand-mediated cytotoxicity was investigated. Three novel, selective,
small-molecule EPAC1-regulators with agonist properties and good safety profiles were
identified, which can serve as promising lead compounds for drug development
Managing sociotechnical risks in infrastructure projects : Sociotechnical Systems (STS) perspectives on systems
Get PDFAs systems become larger, more complex and integrated, the cost of failure increases
rapidly, leading to a need for effective risk management tools. However, conventional
risk management tools such as the ones based on hazard analysis or accident causation
analysis have a narrow focus on either human or technical actors and on single causal
chains at one organisational level. This led researchers to introduce the concept of
Sociotechnical Systems (STS), involving the interaction of human and non-human
technical components. The present study was conducted with the aim of developing
ways of applying STS principles and STS-based methods to improve the risk
management in large infrastructure projects. Initially, the sets of STS principles for the
system design, which had been developed so far, were identified and then integrated and
synthesised to produce a list of 20 core STS principles for applying them further in the
current study. A comprehensive literature review of the work done in this field since its
inception in the 1950s was then conducted, producing a unified list of 103 STS-based
methods. These methods were then evaluated for their validity and visibility
(occurrence).
To identify and analyse major risks in complex infrastructure projects from an STS
perspective, an observational case study of a large-scale collaborative design project at
Heriot-Watt University was conducted, including running the surveys and interviews
with the project participants. The aim was to find out if the presence or absence of the
20 STS principles and 18 associated risk factors affected the performance of the teams.
It was found that the team performance was strongly related to the presence or absence
of STS principles that was supported by statistically meaningful results of a quantitative
analysis. The same STS principles were then applied retrospectively to a second case
study, which was the construction of the Edinburgh Tram Network, based on
documentary sources and employing the AcciMap and Abstraction Hierarchy (AH)
methods. It was concluded that failure to apply these principles and the resulting risks
could play a major role in the failure to deliver the project on time and within budget.
Finally, a five-phase framework was constructed for STS-based risk management
framework of infrastructure projects, with the guideline principles aligning the existing
risk management framework with STS theory
Incomplete quantum oblivious transfer protocols
Get PDF1-2 oblivious transfer is a cryptographic primitive in which a sender, Alice, holds two bits
and a receiver, Bob, obtains exactly one of them in such a way that Alice does not learn
which bit Bob obtained. Quantum oblivious transfer cannot achieve information theoretic
security, unless additional restrictions are imposed.
We examine imperfect oblivious transfer protocols that allow both Alice and Bob to
cheat successfully with some probability greater than a random guess. Past research has
found security bounds to be set at 0.749 for pure symmetric states, and 2/3 in general. We
generalise the security bound of 0.749 and investigate average security ensured by state
testing. We discuss how an example protocol may be implemented using coherent states
and homodyne detection, though high error rates and testing requirements may make it
undesirable for application.
We investigate the new class of incomplete quantum oblivious transfer, in which Bob
may obtain a wrong bit value with an inherent protocol failure probability, Pf . This failure probability allows us to design non-interactive quantum oblivious transfer protocols
with security against the sender, Alice. We provide some examples for protocol implementation based on both coherent states using homodyne and optimal measurements, and
on single photon states. We classify all quantum oblivious transfer protocols using pure
symmetric states where the sender cannot cheat, and numerically show that our example
protocols using qubit and ququart states meet the best possible performance bound.James Watt scholarshi
Identity construction and felt-accountability of Palestinian and Israeli human rights activists : the case of the Gaza Strip
Get PDFThis study critically explores the relationship between identity construction and felt-accountability amongst human rights activists working in Palestinian and Israeli
advocacy NGOs from a postcolonial perspective. Prior accounting research in NGOs
has prioritised the relational and functional accountability of NGOs over individual
accountability of their members. Moreover, advocacy NGOs have not received similar
attention compared with development and welfare NGOs. This thesis addresses the new
construct of felt-accountability using Postcolonial Theory to explore the impact of
postcolonial identity on activists' professional identity vis-à-vis felt-accountability. For
this purpose, I conducted 25 semi-structured interviews with 14 Palestinian activists
working in Palestinian advocacy NGOs and 11 Israeli activists working in Israeli
advocacy NGOs, of whom seven activists introduce themselves as Palestinians despite
their Israeli citizenship. I adopted the critical discourse analysis using Fairclough's
dialectical-relational approach to analyse the interviews narratives at the three-level
analysis (Textual, Discursive and Social). The study provides theoretical and empirical
insights about the construction of a postcolonial identity by activists. It reveals that
activists engage in identity work and adopt multiple tactics to manage their postcolonial
and professional identities, which influences their enactment of felt-accountability. The
study suggests felt-accountability as a by-product of identity that has an affirmative role
in affirming the authentic identity of the colonised and their representation of the Self.
This reciprocal impact has resulted in distinctive forms of felt-accountability, as well as
several noticeable limitations and dark sides. It also explains how felt-accountability is
perceived at individual and collective levels. Contrary to prior research in the field, this
study reveals that felt-accountability, which is discursive and reflexive in nature, does
not necessarily match the imposed accountability of advocacy NGOs. As a result,
activists find themselves in conversations of accountability with their NGOs in which
they exchange their power relations to settle the two accountabilities. This study has
several contributions drawing attention to the significance of identity in shaping felt-accountability, which NGOs and their funders should consider when accountability is in
demand. It reveals the emancipatory potentials of felt-accountability associated with
innovation, creativity, and commitment, hence assisting advocacy NGOs in pursuing
their objectives and protecting their victims. The study encourages future research to
focus more explicitly on how other identities, e.g. gender in NGOs, could facilitate the development of specific types of accountability in different organisational settings, e.g.
social movements, and how felt-accountability could enable organisational members to
change their current identity positions.James Watt scholarshi
Structural and physical properties of selected complex chalcogenides
Get PDFThe structure and physical properties of a selection of mixed-metal
chalcogenides have been investigated. Materials covered in this study have
shown a range of unusual behaviours.
GeV4S8 has been successfully synthesized in order to investigate the
structural properties as a function of temperature. These data reveal that there
are three distinct polymorphs over the temperature range 7 ≤ T / K ≤ 32, of
which one had not been previously determined. Neutron diffraction
experiments reveal a series of peak splittings and broadenings upon cooling
to indicate a deviation from the face-centred cubic structure at room
temperature. A reduction in symmetry to R3m, at TS = 32K is observed.
Antiferromagnetic ordering is then associated with a second successive phase
transition at TN = 17 K to Cm, which is a sub-group of R3m. This monoclinic
phase has previously not been reported.
A new series has been prepared through substitution of chromium with
indium in Cr1-xInxGeTe3 (0 ≤ x ≤ 1) to investigate the effects of diluting the
magnetic cation on the structural, physical and magnetic properties. CrGeTe3
crystallises in space group R3ത with a three-layer repeating unit. It consists of
hexagonally close packed layers of Te2- ions, with Cr3+ ions and (Ge2)
6+
dumbbell pairs occupying octahedral holes in only every other layer. The
unoccupied layers persist throughout the series; however cationic ordering
within the layers of Te2- ions results in different stacking sequences.
Cr1-xInxGeTe3, x = 0, 0.1, 0.2, 0.5, 0.6 samples have a range of ferromagnetism
that can be described using Curie-Weiss law, but they also have regions of
spin glass dominated behaviour below the ‘freeze’ temperature, Tf.
Semiconducting data showed samples did not exhibit thermally activated
conduction but were found to fit a variable-range-hopping model that
represents electrical conductivity in three-dimensions. At x = 0, Seebeck
coefficients are large and positive, however for x = 1, markedly different
behaviour is observed. InGeTe3 undergoes a change in the dominant charge
carriers from electrons to holes at 245 K
Controlling and learning constrained motions for manipulation in contact
Get PDFMany practical tasks in robotic systems involving contact interaction with the environment, such as cleaning windows, writing or grasping, are inherently constrained,
in that both the task and the environment impose constraints on the robot’s motion.
While constraints from manipulation motions in contact represent a challenge when
modelling and controlling such robotic systems, they might also be an opportunity,
if exploited for decomposing complex controllers into simpler ones that are easier to
design, implement, test and even learn from data.
Modelling such systems requires incorporating these constraints in the robot’s dynamic model. In this thesis, I define the class of Task-based Constraints (TbCs) and
prove that the forward dynamic models of a constrained system obtained through
the Projected Dynamics (PD) and the Operational Space Formulation (OSF) are
equivalent. Establishing such equivalence required: reformulating the PD constraint
inertia matrix, generalizing all its previous distinct algebraic variations; and generalizing the OSF to rank deficient constraint Jacobian matrices. This generalization
allows us to numerically handle redundant constraints and singular configurations,
without having to use different controllers in the vicinity of such configurations.
Furthermore, I show that we can recover both operational space control with
constraints and the hybrid position/force control in the operational space from a
multiple Task-based Constraint abstraction. I then propose a control and trajectory
tracking approach for wiping the train cab front panels, using a velocity controlled
robotic manipulator and a force/torque sensor attached to its end-effector, without
using any surface model or vision-based surface detection. The control strategy
consists of a hybrid position/force controller, adapted from the Operational Space
Formulation, that aligns the cleaning tool with the surface normal, maintaining a setpoint normal force, while simultaneously moving along the surface. The trajectory
tracking strategy consists of specifying and tracking a two dimensional path that,
when projected onto the train surface, corresponds to the desired pattern of motion.
An experiment with the Baxter robot to wipe a highly curved surface with both a
spiral and a raster scan motion patterns validates the approach. I also implemented the same approach in a scaled robot prototype, specifically designed to wipe a 1/8
scaled version of a train cab front, using a raster scan pattern.
Learning these type of control policies subject to constraints is a challenging
problem. This thesis proposes a Constraint-aware Policy Learning (CaPL) method
that solves the policy learning problem on redundant robots which execute a policy
acting in the null-space of a constraint. This learning approach allows the generalization of learnt control policies across constraints that are unknown during the training
phase. The CaPL method splits the combined problem of learning constraints and
policies into: first estimating the constraint, and then estimating an unconstrained
policy using the remaining degrees of freedom. For a linear parametrization, there
is a closed-form solution for the problem of estimating constraints based on Singular
Value Decomposition (SVD). In this thesis, I propose another closed-form solution
for constraint estimation for the TbC case, which includes estimating the task component without affecting the norm of the constraint matrix, based on Generalized
Singular Value Decomposition (GSVD). I also discuss a metric for comparing the
similarity of estimated constraints, which is useful to pre-process the trajectories
recorded in the demonstrations. An experiment consisting in: learning a wiping
task from human demonstration on flat surfaces; and reproducing it on an unknown
curved surface using a force/torque based controller, to achieve tool alignment, validates the CaPL method. Despite the differences between the training and validation
scenarios, the learnt policy still provides the desired wiping motion.James-Watt Scholarshi
Anomaly detection & object classification using multi-spectral LiDAR and sonar
Get PDFIn this thesis, we present the theory of high-dimensional signal approximation of multifrequency signals. We also present both linear and non-linear compressive sensing (CS)
algorithms that generate encoded representations of time-correlated single photon counting (TCSPC) light detection and ranging (LiDAR) data, side-scan sonar (SSS) and synthetic aperture sonar (SAS). The main contributions of this thesis are summarised as
follows:
1. Research is carried out studying full-waveform (FW) LiDARs, in particular, the
TCSPC data, capture, storage and processing.
2. FW-LiDARs are capable of capturing large quantities of photon-counting data in
real-time. However, the real-time processing of the raw LiDAR waveforms hasn’t
been widely exploited. This thesis answers some of the fundamental questions:
• can semantic information be extracted and encoded from raw multi-spectral
FW-LiDAR signals?
• can these encoded representations then be used for object segmentation and
classification?
3. Research is carried out into signal approximation and compressive sensing techniques, its limitations and the application domains.
4. Research is also carried out in 3D point cloud processing, combining geometric features with material spectra (spectral-depth representation), for object segmentation
and classification.
5. Extensive experiments have been carried out with publicly available datasets, e.g.
the Washington RGB Image and Depth (RGB-D) dataset [108], YaleB face dataset1
[110], real-world multi-frequency aerial laser scans (ALS)2 and an underwater multifrequency (16 wavelengths) TCSPC dataset collected using custom-build targets
especially for this thesis.
6. The multi-spectral measurements were made underwater on targets with different shapes and materials. A novel spectral-depth representation is presented with
strong discrimination characteristics on target signatures. Several custom-made
and realistically scaled exemplars with known and unknown targets have been investigated using a multi-spectral single photon counting LiDAR system.
7. In this work, we also present a new approach to peak modelling and classification
for waveform enabled LiDAR systems. Not all existing approaches perform peak
modelling and classification simultaneously in real-time. This was tested on both
simulated waveform enabled LiDAR data and real ALS data2
.
This PhD also led to an industrial secondment at Carbomap, Edinburgh, where some of
the waveform modelling algorithms were implemented in C++ and CUDA for Nvidia TX1
boards for real-time performance.
1http://vision.ucsd.edu/~leekc/ExtYaleDatabase/
2This dataset was captured in collaboration with Carbomap Ltd. Edinburgh, UK. The data was
collected during one of the trials in Austria using commercial-off-the-shelf (COTS) sensors
Identity, transition to motherhood and consumption choices
Get PDFA life course transition, such as becoming a mother, can have a profound effect on
consumption choices as the new role is subsumed into identity. This thesis explores if
and how perceptions of identity and identity transition interact with consumption, in the
context of new motherhood. Research is lacking that explores whether or not
consumption behaviour changes during the transition to motherhood and if it does, why
and how.
This research takes an interpretivist philosophical position and explores through the lens
of consumer culture theory. A phenomenological research strategy was employed,
involving a purposively sampled group of 26 women whose babies had been born in the
previous 12 months. These women were living in the UK and were economically and
socially privileged; 12 had one child, 14 had previous children. Using data from
participant photo diaries and interviews, analysis was thematic and followed a
hermeneutical approach.
This research found that for women in this sample, when instability of identity and, in
turn, instability of status was experienced, social relationships became more important
and focus on consumption intensified, suggesting both compensatory and conspicuous
properties. Learning to negotiate the baby product marketplace seemed to be symbolic
of attaining a desired mother role. Using specific products and brands to display
confidence, competence and commitment in their mother role and parenting style,
women engaged, connected and identified with narrow (often localised) groups of peers
but with time and experience, social influence tended to subside, enabling women to
make freer consumption choices. Furthermore, identity change was experienced as an
evolving process, involving ‘defining moments’, reflections on the past and
expectations for the future. This had specific implications for experiences brought about
by physical baby products, planning for nostalgia through consumption and attitudes
towards sustainable consumption.
This thesis contributes to marketing theory by showing that role identity transition and
status transition are entwined and can intensify compensatory and conspicuous forms of
consumption. For marketing practise, this suggests that attitudes towards product signals
and branding may shift during life course transitions, with implications for lifestyle
segmentation and positioning
Doubly-curved origami and application to deployable reflector antennas for space applications
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