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Calixarene-based supramolecular photocatalysis
Get PDFThis thesis presents the synthesis of BODIPY appended calix[4]arenes for use in
photocatalysis, building on the foundational ideas of Gutsche to utilise calixarene
molecular recognition capabilities for reaction enhancement. It was shown that
host-guest interactions within calixarene molecules increased the effective concentration
of starting materials and the efficiency of the 1O2 [4+2] cycloaddition with α-terpinene.
The first chapter provides necessary background of calixarenes and reactive dyes. The
second presents the synthesis of three BODIPY-appended calix[4]arenes theorised to be
strong photocatalysts based on previous work at Heriot-Watt University. Through
reaction monitoring using 1H NMR spectroscopy it was determined that the presence of
a cavity improved the conversion time of α-terpinene to ascaridole. Chapter three
examined what modifications to the initial photocatalysts had on the speed of α-terpinene
conversion. By introducing a phenolic spacer between the calix[4]arene and BODIPY
units, a deeper cavity was created. Under the same reaction conditions as chapter two,
reactions using these catalysts were seen to be distinctly slower.
Chapter four departs from the initial aim, examining in-situ 1H NMR spectroscopy to
track the conversion of 1O2 mediated reactions more accurately. This proved highly
successful producing data of good quality, although development of experimental
procedure is still required
The traditional marketplace : creating memorable, engaging and authentic cultural consumption experience
Get PDFCreating memorable experiences and offering unique services have become pivotal in the
tourism industry in order to enhance competitiveness and sustainable success. The extant
literature has recognised the fundamental change in contemporary consumers’ behaviour.
Hence, experiences have been increasingly evolving in the tourism industry. In exploring
the current developments and future directions in the tourism literature, this thesis offers
a theoretically rich and well-validated conceptual model, particularly in a culturally
specific field. In doing so, this thesis sheds light on three stages of the cultural
consumption experience by integrating the consumer-based model of authenticity with the
value creation theory.
More broadly, this thesis integrated cultural motivation, sociability, host sincerity, object based and existential authenticity, tourist engagement, perceived value, and memorable
tourism experience into the consumer-based model of authenticity and embedded them
into the larger perspective of service logic in a Turkish heritage context. In particular, the
conceptual model proposed that sincere host-guest interactions, perceived authenticity and
tourists’ engagement are influenced by cultural motivation and sociability, impacting
upon perceived value and memorable tourism experience. To provide a holistic
understanding of interrelationships between three stages of the consumption experience,
data was collected in two sequential phases. The first phase consisted of a qualitative
research approach that involves semi-structured interviews, personal observations, and
field notes. In Phase II, data was collected through a questionnaire to provide a wider
perspective and analysed using Partial Least Squares Structural Equation Modeling (PLS-SEM). Qualitative findings contributed to the factors shaping overall heritage
experiences. The findings of the data supported the conceptual model in determining the
pre/on-site/post phases of the heritage consumption experience. Following this,
quantitative results show that the hitherto separate concepts make a substantial
contribution to the consumer-based model of authenticity. In particular, the quantitative
data demonstrate the interrelationship between these factors, offering complementary
ways of understanding the phenomenon within the non-Western service industry. More
broadly, this thesis identifies components and issues that are significant for tourists
visiting heritage destinations and attractions. The findings of this thesis could have
practical implications for planners, destination managers and tourism policy-makers to
develop competitive advantage and sustainable success
The effect of government policies on the quality of life of returning migrants in county towns in Western China : a case study of Chongqing Municipality
Get PDFSince the ‘Open Door’ policy became widely used in China’s coastal cities in the early
1990s, economic growth in coastal areas (mainly focused on the eastern region) has been
more rapid than those in areas that have not benefitted from economic and urban
development policy priorities (the central and western regions). Some concerns have been
expressed about the quality of life of migrant workers who have been involved in enabling
this growth. Most studies have concentrated on the migrant workers in host cities in
coastal areas (Zhu, 2006; RGNBS, 2007); few studies have focused on returning
migrants’(especially returning peasant workers’) quality of life after their return to their
home cities. This research will particularly focus on returning peasant workers’ quality
of life.
Since the early 1980s, a large number of migrant workers have moved from rural areas
of the western regions in China to coastal cities in the eastern provinces. These workers
found jobs and became temporary residents in the destination cities. However, due to a
variety of complex reasons, most of them have not settled down permanently. In recent
years, as the country has adopted policies to accelerate development in the western
regions and many manufacturers are moving to the west, increasingly migrant workers
choosing to return to their area of origin. However, instead of returning to their original
villages, new return migrants prefer to settle down in county towns close to their original
home, and to engage in non-agricultural work. This returning phenomenon is having an
increased impact on the urbanisation process at the county town level in western China.
More importantly, it raises concerns about the quality of life of these returning migrants
and raises issues for the government, in terms of the need to better accommodate them.
This research aims to develop an understanding of the two-way interaction between the
government’s urban management and social policies and the needs of returning migrants
in county towns of western China, and to identify potential policy improvements to
support the quality of life of returning migrants. To achieve this aim, this research
explores the link between migration and urbanisation in western China, investigates the
status of returning migrants, identifies the main drivers for their return, develops an
understanding of their experience of resettlement, and assesses the effectiveness of
government management and social policies in addressing the needs of these migrants. This research combines both qualitative and quantitative approaches, focusing on
Chongqing municipality in western China as a case study, and selecting three county
towns of the city as the focus of the investigation. In recent years, Chongqing has become
a significant “growth pole” and its development is a microcosm of China and a
representative of the western region. The three county towns within the city municipality
are selected based on their economic level to ensure the study is representative of western
China. Data was collected through a questionnaire survey with 450 returning migrants
and 30 interviews with selected migrants as well as government officials in the different
counties.
The research found that factors that caused migrants in Chongqing to move away were
shortage of job opportunities, very low income and a poor rural living environment,
among others. When central government policies favoured economic development of
Western China, especially after Chongqing was municipalised, economic development
was strengthened, especially in Chongqing city urban areas. A number of migrants
returned to Chongqing, attracted by stronger economic development in local areas. This
research found that return migrants’ quality of life varied depending on individual
conditions. Finally, this research looked into how government policies affected returned
migrants’ quality of life, and identified a range of difficulties returned migrants face,
including changed living environments, integration of urban and rural life, social
activities changes, managing of family relationships and adaption of consumption ideas.
Finally, recommendations are provided focused on setting up effective policies that relate
to returned migrants’ quality of life requirements, such as self-employment support
services, better social provision services, and children’s education services
Three essays on asset pricing studies
Get PDFTraditional consumption-based asset pricing models generally treat the aggregate
stock market as a claim to aggregate consumption. However, according to empirical
evidence, the majority of households consume primary out of wages and live with
no capital gains from risky investments, this implies potential omitted stock market systematic risk sources beyond aggregate consumption. Therefore, this thesis
contributes to investigating alternative pricing instruments other than aggregate consumption growth to capture omitted stock market systematic risks in the traditional
consumption-based capital asset pricing model (CAPM).
This thesis constructs three asset pricing models for wealth redistribution risks, asset
pricing effects of heterogeneous beliefs among wealth classes, and financial stress
risks. A new market systematic risk dimension is uncovered in each model and then
tested using U.S. stock market data.
This thesis firstly incorporates the elevated stockholder consumption volatility into
the long-run risk framework to account for wealth redistribution risks. The capital
variability factor (CRV) is developed to capture the accumulated short-run volatility
effects of wealth redistributive shocks. Secondly, this thesis derives the analytical
solution of stockholder consumption growth to account for stockholder consumption
risks using a robustness control approach. The stockholder consumption share factor
(SCS) is constructed to portray the stockholder consumption dynamics and affords
high asset pricing. Finally, this thesis utilises the long-run risk framework to factor
in that financial stress contributes to the convexity of the price-dividend ratio and,
therefore, serves systematic risks. The financial stress factor (FS) is developed to
explain the cross-sectional return variations of stocks with highly subjective valuations
and are difficult to arbitrage.
This thesis contributes to the field in multiple dimensions. This thesis attempts
to introduce economic variables into data-driven models, therefore shedding light
on the impact of limited participation of households in the stock market for future
research. Also, new market systematic risks are uncovered and counterpart asset
pricing factors are constructed. These findings are important to policymakers as
financial systems are especially vulnerable to systemic risk that cannot be hedged
Modelling cause-of-death mortality
Get PDFThe prime objective of this thesis is to investigate recent trends in cause-specific
mortality in England and Wales. The recent slowdown in mortality rate improvements
is of particular interest. Various modelling processes for the cause-specific mortality
are explored so as to determine the appropriate models for this purpose.
Three main datasets are used for the purpose of modelling the cause-specific
mortality trends in England and Wales. An initial exploratory data analysis is
performed on each dataset in order to investigate any obvious trends in the mortality
experience.
Following the exploratory data analysis of the cause-specific mortality data,
Lee-Carter type models are compared against generalised linear models based on
the cause-specific data from 1950 to 2018. These models are applied to cancers,
circulatory system diseases, external causes of mortality, and infectious diseases in
order to assess their ability and appropriateness for modelling the trends in certain
causes of death over a longer period of time. Generalised linear models under the
Poisson and negative binomial distributions are compared to the Lee-Carter models
with the same distributional assumptions. The generalised linear models under the
negative binomial distribution are found to have better performance when modelling
the chosen causes of death and are used to model the cause-specific mortality trends
in the subsequent works.
This thesis provides enhanced insight into the quantification of cause-specific
contributions to the slowdown in all-cause mortality rate improvements in England
and Wales for the period from 2001 to 2018. The causes considered herein include
cancers, circulatory system diseases, digestive system diseases, endocrine system
diseases, external causes of mortality, genitourinary system diseases, infectious
diseases, mental and behavioural illnesses, musculoskeletal system diseases, nervous
system diseases, respiratory system diseases, and deaths from all other causes.
Breakpoint analysis techniques are used for the purpose of determining the location
at which mortality improvements begin to slow down. Cause-specific contributions to
the slowdown in improvements are determined by comparing improvements in various
scenarios. This work is also extended to include future projections of cause-specific
mortality scenarios. The corresponding results provide insights into causes of death
that are drivers of life expectancy improvements.
Finally, generalised linear models are used to model the cause-specific mortality
experience in England from 2001 to 2016 when additional information about the
geographical region as well as the income deprivation decile for the considered
population is included. Following the work performed on cause-specific contributions
to mortality improvement slowdowns, knowledge about breakpoints in cause-specific
mortality trends is applied in the resulting models. The results of these analyses
enable a better understanding of cause-specific mortality trends in England in relation
to income deprivation deciles and geographical regions.
The research in this thesis makes valuable and applicable advancements in the field
of cause-of-death mortality. The findings are of benefit to researchers, policy-makers
and insurance professionalsJames Watt Scholarshi
Antennas and beam-steering arrays for polarization diversity and full-duplex applications
Get PDFThis thesis presents new designs for polarization diverse dielectric resonator antennas
(DRAs) as well as antennas that can offer efficient full-duplex (FD) functionality. Basically, this research effort has been completed to meet the demands of modern tracking
systems as well as in-band full-duplex communication systems. For these applications
antenna polarization control, compatibility, co-location, and isolation are the important
parameters to support these high-performance systems.
The first part of the thesis covers the challenges of modern radio frequency (RF)
environments where the proposed polarization reconfigurable antennas are introduced.
At first, a multi-port DRA is outlined as a possible candidate for the global positioning
system (GPS) and the Global Navigation Satellite System (GNSS). To further advance
this original design, and in an effort to reduce the size whilst maintaining polarization
control, an integrated circuit was also proposed and tested.
Advancing from the research work of phase polarization control using DRAs, the
second part of the thesis studies other new antennas which are suitable for FD communications. Those antennas offer high isolation which makes the signal recoverable for those
FD systems. To advance the state-of-the-art, an H-shaped slot antenna arrangement with
parasitic patches and dual-differential feeding was proposed. The antenna architecture
was investigated with both external and integrated feed systems and both prototypes offer
high isolation levels. The single-element was further integrated into a 1×4 antenna array
which was shown to offer similar isolation levels and with the capability to beam steer.
Further research included high isolation antennas for operation in the 5G mm-wave
band. In particular, a new FD pattern reconfigurable antenna was proposed which can
be used in dual-polarized radars and other FD systems. Depending on the input phase
excitation, the beam pattern control can be established with sum or difference patterns
or both. Also, the antenna concept was further extended into a novel FD antenna array.
This array has a similar common and/or differential feeding which can provide sum or
difference patterns in the far-field. Also, an external Butler matrix was used to investigate
the beam-steering capabilities of the array. These antenna systems also have applications
for dual-polarized radars, retro-directive arrays, and other beam-tracking scenarios which
require high inter-port isolation.James Watt Scholarshi
Bedload transport and bed evolution under unsteady hydrographs
Get PDFUntil recently, river channel response has generally been investigated under a single
unsteady flow hydrograph that does not represent a typical flood condition. The river
channel often experiences significantly different bedload transport and bed evolution
under unsteady sequential flow conditions. At present, however, there is a significant
lack of understanding of the interaction between hydrograph flow parameters and the
response of the river channel over sequential flood hydrographs.
In order to improve our understanding of a river channel response under sequential flow
conditions, a comprehensive experimental study was conducted in a flume facility. The
novelty of this research work lies in (i) the natural-shaped sequential hydrographs; (ii) the
identification of the isolated and combined influence of hydrograph parameters on
sediment transport characteristics and bedform development; (iii) linking the bedload
transport characteristics to the bed evolution characteristics over sequential flow
conditions; and (iv) development of a bedload yield prediction model for the sequential
flow condition.
The difference in the channel response for a single hydrograph and sequential hydrograph
was found to be significant for the bedload rates (reducing trend over the subsequent subhydrographs), bedload yields (i.e., discrepancy ratio of 1.5 – 2), bedform changes (i.e.,
small scale to large scale bedform), and surface roughness (i.e., discrepancy ratio of 1.2
– 1.8), but less significant for channel slope and bedform dimensions. Further, the
individual influence of hydrograph parameters (water work, and unsteadiness) on bedload
yields was evaluated that confirmed water work parameter was an important parameter
and had a primary influence on sediment transport while unsteadiness parameter had a
negligible influence. An improved bedload yield model was developed for yield
prediction over the sequential flow hydrograph that is applicable to a wide range of bed
material and unsteady flow conditions. Finally, recommendations on the application of
the sequential flood modelling approach for flood management are outlined
Adaptive optics for volumetric microscopy
Get PDFVolumetric microscopy allows three dimensional information to be captured in a single image, but the imaging quality can be adversely affected
by optical aberrations. We investigate the robustness and efficiency of
optical aberration compensation for widefield and volumetric microscopy
using iterative image-based - or sensorless - modal adaptive optics (AO).
In this thesis, we use extensive numerical modelling to show that the limiting factors for an accurate modal correction are measurement linearity
and non-linear modal crosstalk. We demonstrate that estimating 4 metric values per mode provides overall better and more robust estimates
of modal amplitudes, regardless of initial Strehl or signal-to-noise ratio,
as well as minimising the total number of photons used for correction.
We show that accurate aberration estimation can be obtained for up to
1 radians RMS of initial aberration; and an excellent AO correction can
still be obtained beyond this range when an appropriate optimisation algorithm is employed. In addition we quantify the impact of out of focus
light and three dimensional sample structure on the correction capability. We also present an adaptive optics correction system employed on
an Olympus microscope, and demonstrate image sharpening on both two
dimensional and three dimensional images
Real-space imaging of OH radicals scattering from liquid surfaces
Get PDFA novel technique for studying the dynamics of gas-liquid scattering was used to image
the products of OH radical collisions with low-vapour-pressure liquids that served as
proxies for the surfaces of atmospheric aerosol particles. A pulsed molecular beam of
OH was aimed at layers of squalane, squalene and perfluoropolyether either along the
normal to the surface or at 45° to it. The OH molecules were intercepted above the surface
by pulsed laser light shaped into a sheet and probed by exciting laser-induced
fluorescence. The emitted photons were collected, intensified, and finally imaged
creating images in which spatial distributions of the OH number density were recorded.
Controlling the delay between the production and probing of the projectiles allowed for
capturing the OH pre- and post-collision. The experimental images were then used to
reveal information about the dynamics of collisions between OH and organic liquid
surfaces.
The images allowed, for the first time ever in the field of gas-liquid interactions, the
complete angular distribution of scattered products to be measured, including backward
scattering, along or close to the incidence angles. The measured scattered OH angular
distributions were found to be dependent on the angle of incidence and peaked around
subspecular or specular final angles. The measured most-probable speeds of scattered
OH were superthermal and correlated with the incident and final angles. These, and other,
observations were consistent with a predominantly impulsive mode of scattering from
atomically rough surfaces
Study of thermochromic nature of VO2 for reconfigurable frequency selection applications
Get PDFThe goal of this project is to investigate the use of vanadium dioxide in reconfigurable
microwave devices such as antennas or filters. The second phase would see the creation
of a more concrete application. The ability of vanadium dioxide (VO2) to change its
structure above a certain temperature is of particular interest. Under 68°C, VO2 behaves
like a dielectric, but when it reaches and exceeds that temperature, it behaves like a metal.
With this in mind, we wanted to demonstrate the possibility of creating a
reconfigurable FSS for spatial filtering by selectively heating the VO2 sample's surface
area. A laser was used to select which area of the sample to heat: by shaping the beam,
we were able to illuminate, and thus heat, only specific areas.
This dissertation also describes the use of the time-resolved microwave conductivity
(TRMC) technique to characterise vanadium dioxide to design these FSS images
projected on the VO2 surface. We show that TRMC is a versatile technique for
determining the electromagnetic material properties and conductivity of VO2 compounds.
This was used to compare the behaviour of several VO2 samples of varying thicknesses
and fabrication technologies.James Watt Scholarshi
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