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Using volunteer-employed photography to inform tourism planning decisions; the case study of St David’s peninsula in Pembrokeshire Coast National Park
Full text linkTourism planning is widely regarded as being highly political, especially as tourism is usually one of a number of land-use options. The community at the destination level is at the receiving end of pressures caused by tourism development. In most cases, there are several interested parties trying to exert an influence on the tourism planning process. However, it is argued that the winners are most often those with the power. In this light, it is considered necessary to develop tourism planning tools that promote participation. The medium of photography is arguably more sensitive to the multidimensional nature of place experiences than is written text or the spoken word. A number of researchers have used volunteer-employed photography (VEP) methods such as photovoice and autophotography, all of which asked real-life protagonists to express their thoughts and feelings through photographs. However, despite the large number of researchers who have suggested that VEP is a powerful technique, it still remains underused, undervalued and relatively under-researched. The case study examined in this thesis was carried out on St David’s Peninsula in the Pembrokeshire Coast National Park in Wales. The area was chosen because of its National Park status, which means that it attracts very high visitor numbers, planning regulations are stricter and conflict between the area user groups is evident. Two user groups, locals and tourists, were given cameras and photo diaries, and were asked to capture what they do and do not appreciate about the area. They were also invited to make planning suggestions regarding existing problems or suggest ways to avoid potential problems. This thesis examines the appropriateness of VEP in assisting tourism planning and demonstrates this by applying VEP to the case study area. The results of the case study demonstrate depth and richness in the dataset and present an experiential technique that can be of great value to the tourism planning process by involving host communities and visitors in the process. Valuable information for tourism planners was collected: natural and built resources were evaluated, strengths, weaknesses and problems and conflict of interests discussed in depth, with the additional advantage of visually representing participants’ views. It is thus argued that VEP is a powerful tool that can be a significant addition to the toolkit for participatory tourism planning at the local level
Effect of gas nuclei on the primary stage of shock–droplet interaction
Full text linkThe presence of entrapped gas in liquids is well-documented, arising from gas solubility, surface irregularities, or prior phase-change events. In this study, simulations are carried out replicating an experiment involving a Mach 2.4 Planar shock interacting with a cylindrical water column, and the results are benchmarked against experimental pressure measurements in which the presence of entrapped air is reported. The liquid droplet is modelled as a homogeneous mixture of liquid and gas using a multiphase flow framework, and a novel relaxation approach is introduced to capture non-equilibrium effects within the mixture region. The effects of Gaseous Volume Fraction (GVF) and relaxation rate on shock attenuation, wave propagation speed, and cavitation are explored. The results reveal that increasing GVF enhances shock attenuation and slows down the wave propagation speed due to the mixture’s higher compressibility. A non-monotonic relationship between relaxation rate and pressure peak intensity is observed, governed by the effect of the relaxation rate on shock diffusivity, with maximum attenuation occurring at intermediate rates. At high GVF, the low wave propagation speed leads to an interaction between the shocks formed internally and around the droplet, which suppresses the rarefaction wave formation. Regarding cavitation, results indicate that lower GVF promotes stronger gas growth due to less shock attenuation. Finally, this study provides a physical explanation for the temporal pressure variations reported in prior numerical works and highlights the critical role of entrapped gas in shock–droplet interaction dynamics
The origin of unusual chemical abundances from the JWST
Full text linkTo understand the formation and evolution of the Universe, it is crucial to understand how and when the first stars formed. The latest observational data reveal unprecedented information about the chem- ical enrichment of the early Universe, which seems to behave differently from the local Universe. The first stars, being very massive, enrich their metal-poor environment in an uncertain way. In order to predict the abundances of the first galaxies, we include nucleosynthesis yields from Population III stars up to 300M⊙, including faint supernovae, Wolf-Rayet (WR) stars and Pair-Instability Supernovae (PISN) into our state- of-the-art hydrodynamical cosmological simulations. Our code (based on Gadget-3) also includes the latest nucleosynthesis yields from population II stars (from Kobayashi et al. 2020) for all stellar mass ranges. We predict the chemical abundance evolution of galaxies for different elements from the early Universe to the local Universe. We first test the modelling of stellar feedback by comparing the observed evolution of mass–metallicity relations (MZR) and metallicity gradients of the interstellar medium. We then com- pare our model including Population III stars with observational data from the James Web Space Telescope (JWST). For elemental abundances, we find that the N/O abundance gives a systematically higher value, comparable to the observational data of very high-redshift galaxies such as GN-z11
Managing aflatoxin risk in the peanut supply chain using quantitative metrics
No full textThe Food Safety Objective (FSO) is a concept that specifies the maximum level of hazard that can be tolerated in a food at the time of consumption, guaranteeing an appropriate level of protection for consumer health. It is a tool that provides risk management throughout the food production chain from the field to the consumer. The application of this concept to mycotoxins was performed for the first time for aflatoxins in peanuts, but in a conceptual and theoretical way, without applying quantitative metrics. FSO metrics for mycotoxin management have been applied to aflatoxins in pistachios and, more recently, to ochratoxin A in coffee. A challenge that is still present and constant in peanut cultivation is the presence of aflatoxins, which results in a reduction of quality and a decrease in commercial value. Aflatoxins are the most potent recognized liver carcinogens and are currently classified by the International Agency for Research on Cancer (IARC) as Group 1 carcinogens. Measures to prevent and reduce aflatoxins in peanuts must be taken at all stages of the peanut production chain. This study aims to apply the FSO approach to assess aflatoxin hazard in peanuts using quantitative data. It also aims to establish quantitative limits at various stages of the peanut supply chain under different scenarios
Automated novel real-time framework for rainfall data imputation in flood early warning systems
Full text linkReal-time flood warning systems play a crucial role in mitigating impacts of flooding. However, their performance is highly dependent on input data, which can often contain missing values. While data imputation techniques have been widely applied in pre-processing stages, their integration into real-time operations remains underexplored. This study presents a real-time automated decision support system that integrates a soft-voting stacked data mining ensemble model comprising decision tree, K-nearest neighbour, Naive Bayes, Neural Network, Support Vector Machine, Discriminant Analysis, and Gaussian Regression. The system also incorporates hydrological–hydraulic event identification, external benchmarking, and a multi-data fuzzy weighted spatial imputation framework. The effectiveness of the proposed method was evaluated through a real-world case study involving a flood early warning system in an urban drainage network in London, UK. Comparative analyses were conducted against well-established artificial intelligence model, and a sensitivity analysis was performed for further assessment. Results showed that all types of missing data were correctly identified with a precision exceeding 90 % and were accurately imputed - particularly in situations where other models failed to recognise current rainfall values during the onset, peak, and falling limb of events (with no reduction in accuracy compared to the best-performing benchmark models). For the 3-h-ahead flood forecasting, the proposed method reduced the normalised root mean square error by up to 30 % compared to alternative approaches. To ensure the generalisability of the approach, additional locations across the UK were used for validation, which demonstrates the stability and robustness of the system, with only minor error variations
Combustion of Alternative Fuels : Opto-Mechanical Design and Optical Investigation
Full text linkThere is a considerable amount of research that presents observations and measurement results obtained from optically accessible reactors such as piston engines and constant volume chambers. However, the aspect of design and relevant information regarding the optical access are not sufficiently explored in the existing publications. A review of literature on optical access for high-pressure and high-temperature design cases was conducted and is presented along with a comparison of optical materials. It was found that the optical materials have sufficient mechanical strength; however, there were certain limiting factors of design, namely the working temperature, the required electromagnetic (EM) wave range, and cyclic loading. It is especially difficult to carry out an accurate design for cyclic loading, as the literature lacks the relevant data for optical materials. As a result of the significant uncertainty arising from the inconstancy of design data, it is suggested that the value of the safety factor should be between two and five, depending on the probability of failure and risks. The design process is shown in detail for two case studies of the opto-mechanical design of pressure vessels. Utilising the optical access, a high-speed imaging system was used to record the ignition and flame kernel formation in the internal combustion engine. A range of fuels were investigated, including gasoline, isooctane, and a few alternative renewable fuels: E85, M85, and hydrogen. The experiments were conducted at stoichiometric conditions for the liquid fuels and φ=0.67 for hydrogen at various engine speeds and compression ratios. A novel analysing method was proposed to process the acquired raw optical data, where ellipses, rather than conventional spheres, were fitted onto image projections of the visible light emitted by the flames. A cross-comparison of the results with the available data from the literature was also conducted. The large amount of optical data allowed the statistical evaluation of the flame area, flame speed and a flame-shape descriptor. The image analysis showed that the ellipse fitting method provided a 50–100 % better fit and thus allowed a more accurate description of the flame propagation properties. The results indicated that gasoline and isooctane had similar flame propagation behaviour, but a significant difference was observed between these fuels and E85, M85 and hydrogen. Similarities were found between the propagation characteristics of M85 and hydrogen, showing the fastest propagating flames among all the fuels. The statistical analysis found that the precision of the flame speed measurement and the roundness of the flames increase with the engine speed, compression ratio, and time elapsed after ignition
Women's experiences of induction of labour: a qualitative study
Full text linkThis qualitative study examines women’s experiences of induction of labour from the perspective of informed choice and decision-making. Induction currently affects 23.3% of all births in England (BirthChoiceUK Professional, 2014). Although much research has been conducted into clinical aspects of induction in recent years, very few studies have considered it from the woman’s point of view. The current discourse on woman centred care is conceptualized as empowering women to make informed choices and to have control over their reproductive health. From this perspective, this study sets out to explore the circumstances in which women gain information and make decisions about induction and how induction affects their overall birthing experience. Data was collected through semi-structured interviews with 21 first-time mothers approximately 3-6 weeks after giving birth and was analyzed thematically. The findings indicated that information from health professionals was sparse and often difficult for women to relate to their own circumstances, indicating a need for information to be individualized to women’s specific needs. There was a notable disparity between women’s expectations of induction and their actual experiences. Time on the antenatal ward was likened to a state of prolonged liminality, where women were separated from everyday life and subjected to restrictive policies and regulations. Following induction, there was a notable shift in women’s attitudes towards medicalised childbirth, with one third favouring the idea of a caesarean section in future. Despite the current discourse on informed choice, this study supports Mavis Kirkham’s theory that it exists more in rhetoric than in reality and is hampered by the prevailing structure of maternity care. In order to improve the induction experience, a more woman-centred model of care is called for
Scattering Ice Clouds
Full text linkThe 2013 meeting of the Intergovernmental Panel on Climate Change concluded that the coupling of clouds to the Earths climate is one of the biggest uncertainties faced in predicting climate change today. Cirrus clouds are of particular interest because the extensive variability in particle size, shape and complexity poses a number of challenges in the accurate modelling of optical properties. The dependence of the single-scattering properties on particle shape demand accurate representation of the crystal geometries in scattering models, geometries which can vary from simple hexagonal prisms to complex multi-branched aggregates. This work, presented as a series of papers, uses laboratory studies to investigate the single scattering properties of ice crystals. Of particular focus here are columns with internal cavities. The first paper investigates the phase function, P11 and asymmetry parameter, g of varying crystal habits, whilst the second paper focuses on polarised scattering. One of the main findings is the difference in internal structure between hollow columns grown at warmer temperatures (􀀀7°C) and those grown at colder temperatures (􀀀30°C). Measurements were used to create new particle geometries for use in scattering models. The third paper makes use of findings from papers 1 & 2 to create an optical parametrization for cirrus, utilizing the new particle geometry
Investigating various nonlinear vibration problems using VIBRANT: A tool based on Abaqus and Python
Full text linkThis paper investigates nonlinear vibration problems using VIBRANT (VIbration BehaviouR ANalysis Tool), a tool based on Python and Abaqus for the detailed analysis of complex mechanical systems. VIBRANT employs time-marching algorithms to perform time domain finite element simulations under harmonic excitation, predicting frequency domain behaviour. It addresses a significantly large range of nonlinearities, including contacts and large displacements, as it uses a commercial finite element software package Abaqus, while reducing computational time through parallelisation. The tool’s capabilities are examined through three academic benchmark examples. The first example examines a geometrically nonlinear Timoshenko beam subjected to large displacements, which highlights the nonlinear behaviour due to significant deformation associated with stiffness nonlinearities. The second example is a bar forced to move in axial direction by its frictional clamps that are modelled using Jenkins contact elements. This example is also a demonstration of a stiffness nonlinearity. The third example involves an Euler-Bernoulli beam with a frictional contact element, which demonstrates the effects of damping nonlinearities by the application of a localised Coulomb friction element. All examples serve to validate VIBRANT’s accuracy and efficiency in capturing the characteristics of nonlinear systems, emphasising its potential for industrial applications, particularly in aerospace engineering. VIBRANT’s capacity to model a wide range of nonlinearities and to automate frequency sweep analysis with minimal manual intervention represents a significant advantage, providing a reliable and efficient approach to modelling and analysing dynamic responses in engineering structures