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This study investigates the potential application of post-tensioned concrete-filled FRP tubes (CFFT) for wind turbine towers. A 5.8 m tall hollow core CFFT tower with a tapered profile (base and top diameters of 533 and 417 mm, respectively) was tested experimentally; first under free vibration conditions, followed by cyclic loading under concentric and eccentric lateral loads, and finally under monotonic loading to failure. The tower failed in flexure near the base as a result of GFRP tube rupture. Preliminary results suggest that CFFTs can be a promising alternative to conventional wind turbine tower systems, offering transportability, durability, and tailorable structural characteristics., Paper 110

Functionally Graded Materials represent the next generation of engineering design for metal and plastic components. In this research, a specifically modified and optimised 3D printer was used to manufacture functionally graded polyether ether ketone components. This paper details the design and manufacturing methodologies used in the development of a polyether ether ketone printer capable of producing functionally graded materials through the manipulation of microstructure. The interaction of individually deposited beads of material during the printing process was investigated using scanning electron microscopy, to observe and quantify the porosity levels and interlayer bonding strength, which affects the quality of the final parts. Specimens were produced under varying process conditions and tested to characterise the influence of the process conditions on the resulting material properties. The specimens printed at high enclosure temperatures exhibited greater strength than parts printed without the active addition of heat, due to improved bond formation between individual layers of the print and a large degree of crystallinity through maintenance at these elevated temperatures.

Biodegradable polyesters are a popular choice for both packaging and medical device manufacture owing to their ability to break down into harmless components once they have completed their function. However, commonly used polyesters such as poly(hydroxybutyrate) (PHB), poly(lactic acid) (PLA), and polycaprolactone (PCL), while readily available and have a relatively low price compared to other biodegradable polyesters, do not meet the degradation profiles required for many applications. As such, this study aimed to determine if the mechanical and degradation properties of biodegradable polymers could be tailored by blending different polymers. The seawater degradation mechanisms were evaluated, revealing surface erosion and bulk degradation in the blends. The extent of degradation was found to be dependent on the specific chemical composition of the polymer and the blend ratio, with degradation occurring via hydrolytic, enzymatic, oxidative, or physical pathways. PLA presents the highest tensile strength (67 MPa); the addition of PHB and PCL increased the flexibility of the samples; however, the tensile strength reduced to 25.5 and 18 MPa for the blends 30/50/20 and 50/25/25, respectively. Additionally, PCL presented weight loss of up to 10 wt.% and PHB of up to 6 wt.%; the seawater degradation in the blends occurs by bulk and surface erosion. The blending process facilitated the flexibility of the blends, enabling their use in diverse industrial applications such as medical devices and packaging. The proposed methodology produced biodegradable blends with tailored properties within a seawater environment. Additionally, further tests that fully track the biodegradation process should be put in place; incorporating compatibilizers might promote the miscibility of different polymers, improving their mechanical properties and biodegradability.

In service, externally bonded CFRP materials may be exposed to fluctuating moisture levels and harsh temperature cycles, which can potentially reduce their durability and degrade the CFRP-concrete bond. This bond interface is the most critical parameter in the structural evaluation of CFRP retrofitted bridges. Full interfacial assessment of the bond behaviour for structural performance evaluation should include the identification of defects, estimation of defect size, the potential effects on structural behaviour, and continuous monitoring of the evolution of the defects over time. In this paper, 490 pull-off tests were conducted following ASTM D7522 to investigate the integrity and variability of the bond strength of the CFRP-concrete interface for an externally strengthened diaphragm from a Canadian bridge having two to four layers of CFRP strips in a bond critical application. The bond strength values, which ranged from 0.66 MPa to 5.54 MPa, generally confirmed the results of non-destructive testing, including acoustic sounding and infrared thermography which aimed to locate hidden defects behind the strengthening layers. Bond strength and failure modes of both defective and defect-free regions are critically analyzed., Paper 32

Carbon fibre-reinforced polymer (CFRP) materials are lightweight, corrosion-resistant composite materials extensively used to strengthen or retrofit deteriorated concrete bridge components. The retrofitting process is usually a multi-stage manual process with the inherent capability of introducing defects at the various stages of work. In this paper, a methodological approach involving various nondestructive testing (NDT) techniques has been developed for a detailed condition assessment of the state of damage in deteriorated concrete bridge diaphragms. These three diaphragms from a major Canadian bridge were externally retrofitted with multiple layers of CFRP materials and subjected to years of environmental exposure. In addition, a detailed comparison of results obtained from the NDTs and visual inspection is presented. Several issues were identified, including CFRP delamination, material incompatibility, discolouration due to corrosion, inter-fibre cracks, and fundamental problems arising from the construction of the bridge diaphragms and installation of the CFRP., Paper 31

To report the outcomes of dogs that underwent primary repair of gastroduodenal perforations associated with the administration of nonsteroidal anti-inflammatory drugs (NSAID). A secondary objective was to identify clinicopathological findings that predisposed dogs to postoperative death.Retrospective study.Eleven dogs with complete gastric or duodenal perforation related to administration of an NSAID that underwent primary surgical repair.Medical records were reviewed for dogs that presented with peritonitis due to a complete gastroduodenal perforation while receiving NSAIDs between November, 2011 and January, 2021. Data collected included patient characteristics, clinical signs, clinicopathological results, surgical details, and postoperative management and outcome.All dogs were large breeds (mean weight 42 kg; range 22-75 kg), with a mean age of 7.35 years. Nine dogs from a total of 11 (82 %) received a concurrent corticosteroid and NSAID, or a higher dose/frequency/length of NSAID administration than recommended by the manufacturer. All gastroduodenal perforations were found in the upper gastrointestinal tract. Eight of 11 (73%) dogs survived to discharge. The median postoperative duration of follow up was 444 days (range 2-1460 days). No association was detected between ulcer size or location and mortality.Most dogs who underwent primary repair of complete gastroduodenal ulcers survived. Gastroduodenal perforations were generally due to the administration of higher or longer doses of NSAIDs, or concurrent administration of another NSAID or corticosteroid.Primary closure may be associated with a high success rate in dogs with full thickness gastroduodenal ulcers.

Feedback is among the most powerful influences on learning a new skill. Surprisingly, very little attention has been given to studying this issue in relation to interactions between school leaders and frontline teachers particularly during the adoption of educational changes. This qualitative study provides findings on feedback provided to teachers by school leaders in relation to the adoption of a new Tanzanian curriculum. The data were collected from teachers and leaders in three schools using document reviews and individual interviews, and were processed through thematic analysis. Findings revealed various technical issues with regard to feedback method, timing, and quality. Factors that influenced these and their likely influences on the professional growth of the teachers are discussed within the context of reviewed literature. Recommendations for policy and practice are provided.

This review aims to describe and compare porcine models of metabolic syndrome. This syndrome and its associated secondary comorbidities are set to become the greatest challenge to healthcare providers and policy makers in the coming century. However, an incomplete understanding of the pathogenesis has left significant knowledge gaps in terms of efficacious therapeutics. To further our comprehension and, in turn, management of metabolic syndrome, appropriate high-fidelity models of the disease complex are of great importance. In this context, our review aims to assess the most promising porcine models of metabolic syndrome currently available for their similarity to the human phenotype. In addition, we aim to highlight the strengths and shortcomings of each model in an attempt to identify the most appropriate application of each. Although no porcine model perfectly recapitulates the human metabolic syndrome, several pose satisfactory approximations. The Ossabaw miniature swine in particular represents a highly translatable model that develops each of the core parameters of the syndrome with many of the associated secondary comorbidities. Future high-fidelity porcine models of metabolic syndrome need to focus on secondary sequelae replication, which may require extended induction period to reveal.