Commercial wind turbine (WT) blades that are now being operational globally, are primarily made of glass-reinforced composites using epoxy or polyester matrix systems, mainly epoxy. The industry is rapidly growing (2100 TWh currently; 17% growth annually) with a forecast of 7400 TWh by 2030. The average lifespan of a WT is 20-25 years, which signifies the importance of repairing the damaged blades. Amongst the methods that have been exploited so far, resistance welding shows eminent potential, due to its ease of operation, promptness of the repair process, and cost effectiveness. Resistance welding was exploited previously for repairing thermoplastic composites. But in this project, repair of thermoset composites was evaluated using thermoplastic welding medium. The project focused on parametric optimisation of resistance welding, evaluation of welding via single lap shear strength, and COMSOL multiphysics modelling to examine the homogeneity of heat-distribution across the welding region. Stainless steel mesh and carbon nonwoven sheet were used as heating elements, while polymethyl methacrylate and thermoplastic polyurethane were used as welding medium. The highest single lap shear strength was shown as 6.4 MPa when nonwoven carbon sheet was used along with thermoplastic polyurethane. COMSOL modelling with a custom-designed heating element showed improvement in thermal homogeneity; however, further modifications will be required to better optimisation of welding.

The effect of silica nanoparticles and brine salinity variation on the wettability alteration of oil-wet surfaces was investigated in this paper. The rock and fluids of Kolo oilfield in Nigeria were used as case study and five brine salinities and two nanoparticles’ concentrations were investigated. The contact angle and Amott wettability index methods were used to investigate the wettability alteration potential of silica nanoparticles on oil-wet surfaces and intact core plugs, respectively. The results of the contact angle tests showed that the use of 1 g/L and 5 g/L silica nanoparticles reduced the oil-wet surface’s angle from 79o to 73o and 71o respectively in aqueous solution. Lower contact angles were however observed with the use of brines of different salinities with the lowest angles (69o and 68o ) being obtained with lowest salinity brine (90D). Which shows that the nanoparticles have the tendency to modify oil-wet surfaces towards waterwet condition irrespective of the brine salinities. Also, wettability alteration towards increasing water-wetness was observed with decrease in brine salinities and increase in the concentrations of the nanoparticles. Finally, the results of the Amott wettability index to water show that the application of nanoparticles modifies the intact rock wettability towards water-wet condition and higher oil production was observed with the spontaneous imbibition of nanofluid with 0.25 wettability index relative to that of the formation brine that was 0.1. The sediments of nanoparticles were however observed on top the rock core and at the base of the cell during the spontaneous imbibition process. This work presents experimental study on the wettability alteration potential of the application of silica nanoparticles in Kolo oilfield reservoir rock and fluids. The study presented in this paper is relevant to the design and implementation of nanoparticles enhanced oil recovery process.

Eusociality, where workers typically forfeit their own reproduction to assist their mothers in raising siblings, is a fundamental paradox in evolutionary biology. By sacrificing personal reproduction, helpers pay a significant cost, which must be outweighed by indirect fitness benefits of helping to raise siblings. In 1983, Jon Seger developed a model showing how in the haplodiploid Hymenoptera (ants, wasps and bees), a partially bivoltine life cycle with alternating sex ratios may have promoted the evolution of eusociality. Seger predicted that eusociality would be more likely to evolve in hymenopterans where a foundress produces a male-biased first brood sex ratio and a female-biased second brood. This allows first brood females to capitalize on super-sister relatedness through helping to produce the female-biased second brood. In Seger’s model, the key factor driving alternating sex ratios was that first brood males survive to mate with females of both the second and the first brood, reducing the reproductive value of second brood males. Despite being potentially critical in the evolution of eusociality, however, male survivorship has received little empirical attention. Here, we tested whether first brood males survive across broods in the facultatively eusocial sweat bee Halictus rubicundus. We obtained high estimates of survival and, while recapture rates were low, at least 10% of first brood males survived until the second brood. We provide empirical evidence supporting Seger’s model. Further work, measuring brood sex ratios and comparing abilities of first and second brood males to compete for fertilizations, is required to fully parameterize the model.

In the UK and the Republic of Ireland, Official Veterinarians (OVs) are employed by the Food Standards Agency and the Food Safety Authority, respectively, as legal authorities for both animal welfare and food safety. However, little is known about job satisfaction in this profession which has the potential to impact professionals’ well-being and performance. Moreover, despite animal welfare issues being a reality that OVs witness, we do not yet understand how OVs perceive these issues at slaughter or whether this impacts job satisfaction. We assessed OVs’ perceptions on job satisfaction and views on welfare at slaughter across the UK and ROI, through an online questionnaire with 113 participants, which included socio-demographic information of participants and questions or statements about different aspects of job satisfaction and animal welfare issues at slaughter. While most OVs committed to their work they reported issues that may compromise job satisfaction, such as often experiencing loneliness at work, threatening situations and sleep disorders. Moreover, job satisfaction was often impacted by animal welfare incidents, and conflicts with food business operators were considered one of the greatest barriers to improving welfare at slaughter. There is also the likelihood of professionals’ individual ethical values being challenged since OVs are virtually certain to witness religious slaughter yet disagree with this practice to the extent that they consider it should be banned. We reveal significant challenges associated with the role of OV that justify creation of a support network to assist and safeguard this profession, as well as animal welfare at slaughter.

BACKGROUND: Vector control remains the most visible method for large scale control of trypanosomiasis; there is a lack of suitable prophylactic drugs and vaccines against trypanosomiases and chemotherapeutic agents remain too expensive and dangerous for most people in endemic areas. Glossina populations are the target units and therefore an in-depth understanding of their ecology is a pre-requisite to the development of effective control measures. SAMPLING METHODS: Refers to methods of catching tsetse flies in the field. Earlier Researchers utilized walking parties to catch flies or standing catch with hand nets. Studies in the 1970s highlighted the shortcomings of these methods. A variety of traps has since been developed for diverse species. POPULATION DYNAMICS: Refers to changes in population abundance over time. Three processes (dispersal, natality, mortality) are involved in determining population levels. Geographic structure is the distribution and abundance within and among populations. Based on direct observations, mark-recapture protocols or radio-tracking, earlier view was that Glossina dispersal was random. Currently, the best available description is a diffusion process; flies at the margins of the distributional range begin the process, which gradually moves inwards. Calculation of growth rates is easier for small closed Glossina populations. There is a consensus among tsetse ecologists that both density-dependent and density-independent factors are important in the regulation of tsetse numbers. POPULATION GENETICS: It encompasses two distinct but related components: demographic and genetic distribution of genetic variation and the result of migration, selection mutation, genetic drift and related factors: New molecular genetics techniques have allowed insights into many fields. CONCLUSION: There have been significant advances in Glossina ecology over the past 3 decades. These have been possible because of the availability of comprehensive data from long-term field studies and the introduction of new molecular genetics techniques that have allowed insights into many fields. Glossina population genetics and manipulation of prokaryotic symbiont species may provide avenues for management innovations to confront the intractable problem of trypanosomiasis in Africa.

Background: The sibling species of the malaria mosquito, Anopheles gambiae (sensu stricto) and Anopheles coluzzii co-exist in many parts of West Africa and are thought to have recently diverged through a process of ecological speciation with gene flow. Divergent larval ecological adaptations, resulting in Genotype-by-Environment (G × E) interactions, have been proposed as important drivers of speciation in these species. In West Africa, An. coluzzii tends to be associated with permanent man-made larval habitats such as irrigated rice fields, which are typically more eutrophic and mineral and ammonia-rich than the temporary rain pools exploited by An. gambiae (s.s.). Methods: To highlight G × E interactions at the larval stage and their possible role in ecological speciation of these species, we first investigated the effect of exposure to ammonium hydroxide and water mineralisation on larval developmental success. Mosquito larvae were exposed to two water sources and increasing ammonia concentrations in small containers until adult emergence. In a second experiment, larval developmental success was compared across two contrasted microcosms to highlight G × E interactions under conditions such as those found in the natural environment. Results: The first experiment revealed significant G × E interactions in developmental success and phenotypic quality for both species in response to increasing ammonia concentrations and water mineralisation. The An. coluzzii strain outperformed the An. gambiae (s.s.) strain under limited conditions that were closer to more eutrophic habitats. The second experiment revealed divergent crisscrossing reaction norms in the developmental success of the sibling species in the two contrasted larval environments. As expected, An. coluzzii had higher emergence rates in the rice paddy environment with emerging adults of superior phenotypic quality compared to An. gambiae (s.s.), and vice versa, in the rain puddle environment. Conclusions: Evidence for such G × E interactions lends support to the hypothesis that divergent larval adaptations to the environmental conditions found in man-made habitats such as rice fields in An. coluzzii may have been an important driver of its ecological speciation.

Establishing sustainable and resilient businesses are among the key drivers behind the unprecedented demand for the transition and transformation of sustainable growth models. Driven by a desire to remain competitive amidst economic turmoil and climate change, organisations are embedding sustainable measures into their long-term goals and strategies. This is demonstrated by developing and implementing Net-Zero targets and associated plans. However, the greatest challenge is whether such momentum will be retained and how organisations can maintain the drive. Although this is a positive move towards climate-related actions from organisations and stakeholders, it is taking longer than anticipated to be realised and actualised. This necessitates the urgency in understanding the intricacies of corporate sustainability matrices. The question as to why attaining a positive climatic state has taken almost half a century needs to be explored when compared to scenarios where the implementation of sustainable related measures has taken less time. This paper provides a review of the barriers that are making sustainability unattractive for corporate organisations. Finance gaps, the complexity of organisational sustainability, reporting frameworks, tools, and procedures coupled with considerable marketing and communication in a business-as-usual environment are key barriers to corporate sustainability. Our findings provide recommendations for policymakers, and stakeholders across the corporate sustainability platform by delivering a holistic approach to overcome the bottlenecks for implementation, action, and monitoring.

The principal purpose of this chapter is to examine aspects of defence logistics, principally operational logistics, in order to shed light on some of the realities that give it its particular character, or at least some of its character. One possible approach is to analyse the defence supply chain and support chain using an analytical framework built around established through life support and supply chain paradigms, concepts, and ideas, drawn from the commercial sector. Another approach is to examine some specific characteristics of defence supply chains and support chains, some of their attributes, and some of their practical realities, and whilst doing so refer to the established paradigms, concepts, and ideas for comparison, but only where it seems appropriate to do so, in the hope that they might to some extent act as reference points by which defence logistics can be better understood by somebody not directly involved in its planning and delivery. One aim of this chapter is to examine the freedoms which defence departments and defence logisticians have in shaping their business, and the factors, or ‘realities’, which constrain them.

This thesis studied the fabrication of piezoelectric transducers and the engineering structural design in pursuit of enhanced piezoelectric behaviour. The research investigated sandwich-based piezoelectric energy harvesters, and a macro fibre composite (MFC) patch as a piezoelectric element. Finite element models of the sandwich structures were established in COMSOL Multiphysics, where the natural frequencies of the first bending modes and the open-circuit voltage at the natural frequencies were predicted. The difference between the numerical voltage prediction and the experimental measurement is within 10%, so that the experimental measurement is able to validate the numerical calculation. It was found that the sandwich with optimised core cellular design, namely the re-entrant honeycomb, could harvest 24.4 μW under base excitation of 1 g p-p magnitude at a first bending mode resonant frequency. Further optimisation on the re-entrant honeycomb core was conducted by introducing functional grading, in pursuit of further piezoelectric energy harvesting performance. Grading was conducted on the re-entrant honeycomb, by varying the cellular wall angle and the optimum grading scheme was found to have a linear variation from 60 ° at the bottom surface, to 45 ° at the top surface. Similarly, the finite element models of sandwiches with functional graded design were established, and it has been found that the experimental result can validate the numerical prediction. It also consisted of a spin-coated P(VDF-TrFE) transducer and sandwich with the optimised graded cellular core producing a maximum 158.7 nW at 2g p-p acceleration. Moreover, a screen-printing system was built, with fully functioning screen exposure, washing, and substrate clamping units. A screen of 15-200 mesh was selected for P(VDF-TrFE) due to a high paste deposition efficiency. The screen-printed piezoelectric devices were assessed for the structural health monitoring of carbon fibre, and glass fibre reinforced composite panels. When the printed piezoelectric transducers were used as both an emitter and a sensor, the dynamic modes could not be captured by the frequency response function spectrum. When a printed transducer was replaced by a macro fibre composite, the modal information was obtained, and the variation of critical modal peaks was observed after the composite panels were impacted at 5 J for once and twice. It was also observed that the printed transducer behaved more effectively as a sensor than an emitter. These observations demonstrated the feasibility of printed piezoelectric transducers for structural health monitoring applications. To enhance the piezoelectric property of the printed transducer, BaTiO3 particles were added into the P(VDF-TrFE) matrix. The optimised concentration for the best piezoelectric coefficient was found to be 5 wt% BaTiO3 in relation to P(VDF-TrFE) polymers. At the optimised concentration, the screen-printed piezoelectric generator exhibited a piezoelectric constant d33 of -33.90 pC/N, dielectric constant of 17.05, and the Young’s modulus of 1.35 GPa. The measurement was used as the material properties of the piezoelectric elements in the finite element models of the smart sandwich energy harvesters. The numerically calculated natural frequencies of the first bending modes and the open-circuit voltage were well validated by the experimental result. Combining the optimised screen-printed piezoelectric harvester with carbon and glass fibre reinforced composite panels, resulted in a measured maximum power output between 2.9 μW and 3.8 μW. This power was generated under 1 g peak-peak (p-p) acceleration at the first bending mode resonant frequency. To demonstrate real applications of harvested energy, a commercial accelerometer was powered by a smart composite energy harvester. The smart composite energy harvester was excited at 5 g peak-peak acceleration and connected to a 100 μF capacitor via a full-bridge rectifier. The energy stored in the capacitor was used to power the accelerometer, and successful measurement was demonstrated. A further development included a screen-printed nonlinear harvester for energy harvesting, where the printed generator was combined with a buckled Duffing nonlinear oscillator with clamp-clamp configuration. The buckled beams were prototyped into rectangular and cellular configurations. The rectangular and cellular configurations provided a maximum power of 0.66 and 0.93 μW, respectively.

Composites have gained widespread acceptance in various industries due to their exceptional performance over the last 10 years. In 2024, industries predominantly employ manual and non-destructive testing (NDT) techniques for routine inspection and maintenance. However, a Structural Health Monitoring (SHM) technology that is low in energy consumption, easy to install and applicable to various working conditions could cater better to market demands. To address this, the thesis focuses on the identification, localisation, and quantification of damage through vibration analysis methods based on Frequency Response Functions (FRFs). It also explores potential challenges in the practical application of these methods. The thesis relies on the integral differential method to measure the variation of FRF between the pristine and damaged stages, referred to as the Difference of Response (DoR) index. A series of carbon fibre composite panels with integrated microfibre composite (MFC) sensors arranged in equilateral triangles were fabricated. Through sine swept-frequency vibration testing at three different frequency ranges (10 Hz to 1 kHz, 1 kHz to 3 kHz, and 3 kHz to 5 kHz), the dynamic responses of the sample in both the impact-damaged and pristine stages were recorded in real-time, allowing for mutual comparison. Combined with damage geometrical dimensions measured by thermography imaging technology, a quantification formula is derived through numerical analysis, demonstrating a segmented linear relation between the DoR and damage size governed by power and logarithmic functions. According to the local effect of the damage, the DoR results of each region in the sample were compared, successfully achieving damage localisation in single and multiple damage scenarios. Additionally, experimental results highlight the significant influence of environmental factors on the dynamic behaviours of the structure. This thesis contributes significantly to the realisation of SHM using traditional vibration methods and addresses a longstanding development gap in this field.