The hope wheel: a model to enable hope-based pedagogy in Climate Change Education.

In response to concerns about climate anxiety and distress, researchers and practitioners in both education and psychology have been investigating the importance of engaging climate hope in Climate Change Education (CCE). Synthesizing recent multidisciplinary research, alongside insights from the development of educational programs, this article proposes a new theoretical model for pedagogies of hope in CCE. The Hope Wheel presents three foundational elements: handrails for educators to hold on to while constructively engaging with climate change (honesty, awareness, spaceholding, action), guardrails for educators to be sensitive to when implementing the handrails (climate anxiety, mis-/disinformation, false hope), and lenses to encourage educators to explore connections between complex societal and planetary challenges (complexity, justice, perspectives, creativity, and empathy). This working model aims to support educators by distilling current learnings from the literature into a visual guide. It depicts essential elements to include, as well as avoid, in order to engage honest, hope-oriented CCE for transformative learning in the face of the climate crisis.

Design and Modification of a Material Extrusion 3D Printer to Manufacture Functional Gradient PEEK Components.

In recent years, the creative use of polymers has been expanded as the range of achievable material properties and options for manufacturing and post-processing continually grows. The main goal of this research was to design and develop a fully-functioning material extrusion additive manufacturing device with the capability to produce functionally graded high-temperature thermoplastic PEEK (polyether ether ketone) materials through the manipulation of microstructure during manufacturing. Five different strategies to control the chamber temperature and crystallinity were investigated, and concepts of thermal control were introduced to govern the crystallisation and cooling mechanics during the extrusion process. 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 affect the quality of the final part. Functional testing of the printed parts was carried out to identify crystallinity, boundary layer adhesion, and mechanical behaviour. Furnace cooling and annealing were found to be the most effective methods, resulting in the highest crystallinity of the part. Finally, a functionally graded material cylindrical part was printed successfully, incorporating both low and high crystalline regions.

Advancements in Functionally Graded Polyether Ether Ketone Components: Design, Manufacturing, and Characterisation Using a Modified 3D Printer.

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.

Structural analysis of a fibre-reinforced composite blade for a 1 MW tidal turbine rotor under degradation of seawater.

This paper presents a structural performance study of a fibre-reinforced composite blade for a 1 MW tidal turbine rotor blade that was designed for a floating tidal turbine device. The 8-m long blade was manufactured by ÉireComposites Teo and its structural performance was experimentally evaluated under mechanical loading in the Large Structures Research Laboratory at the University of Galway. Composite coupons, applied with an accelerated ageing process, were tested to evaluate the influence of seawater ageing effects on the performance of the materials. The material strength of the composites was found to have a considerable degradation under the seawater ingress. As part of the design stage, a digital twin of the rotor blade was developed, which was a finite-element model based on layered shell elements. The finite-element model was verified to have good accuracy, with a difference of 4% found in the blade tip deflection between the physically measured test results in the laboratory and numerical prediction from the model. By updating the numerical results with the material properties under seawater ageing effects, the structural performance of the tidal turbine blade under the working environment was studied. A negative impact from seawater ingress was found on the blade stiffness, strength and fatigue life. However, the results show that the blade can withstand the maximum design load and guarantee the safe operation of the tidal turbine within its design life under the seawater ingress.

Tidal stream to mainstream: mechanical testing of composite tidal stream blades to de-risk operational design life.

Tidal energy has seen a surge of interest in recent years with several companies developing technology to harness the power of the world's oceans where the operational capacity in Europe was over 11 MW in 2020. One such developer is the partnership of SCHOTTEL Hydro (Germany) and Sustainable Marine (UK) who have developed a scalable multi-turbine device equipped with 70 kW turbines and capable of operating in arrays at sites around the world. The technology to harness tidal energy is still at a relatively early stage of development; hence, de-risking of component parts plays a vital role on the road to commercialisation. Despite this, the number of tidal energy blades undergoing test programmes remains small. Two different rotor diameters have been developed for the aforementioned device such that it can be optimised for sites of varying potential. In this paper, a blade from each of the 4.0 m and 6.3 m diameter devices was tested for their responses in natural frequency, static loading and fatigue loading under test standards IEC 62600-3:2020 and DNVGL-ST-0164. Testing saw the survival of a blade in fatigue at a lifetime-equivalent load and the generation of natural frequency, strain and displacement results for both blades. Data generated from the testing as a whole will contribute to the modelling and validation of future tidal blades.

Manufacture of High-Performance Tidal Turbine Blades Using Advanced Composite Manufacturing Technologies.

After wind and solar energy, tidal energy presents the most prominent opportunity for generating energy from renewable sources. However, due to the harsh environment that tidal turbines are deployed in, a number of design and manufacture challenges are presented to engineers. As a consequence of the harsh environment, the loadings on the turbine blades are much greater than that on wind turbine blades and, therefore, require advanced solutions to be able to survive in this environment. In order to avoid issues with corrosion, tidal turbine blades are mainly manufactured from fibre reinforced polymer composite material. As a result, the main design and manufacture challenges are related to the main structural aspects of the blade, which are the spar and root, and the connection between the blade and the turbine hub. Therefore, in this paper, a range of advanced manufacturing technologies for producing a 1 MW tidal turbine blade are developed. The main novelty in this study comes with the challenges that are overcome due to the size of the blade, resulting in thickness composite sections (> 130 mm in places), the fast changes in geometry over a short length that isn't the case for wind blades and the required durability of the material in the marine environment. These advances aim to increase the likelihood of survival of tidal turbine blades in operation for a design life of 20 + years.

Efficient treatment of dairy processing wastewater in a laboratory scale Intermittently Aerated Sequencing Batch Reactor (IASBR).

This Research Communication describes an investigation into the viability of an Intermittently Aerated Sequencing Batch Reactor (IASBR) for the treatment of dairy processing wastewater at laboratory-scale. A number of operational parameters have been varied and the effect has been monitored in order to determine optimal conditions for maximising removal efficiencies. These operational parameters include Hydraulic Retention Time (HRT), Solids Retention Time (SRT), aeration rate and cycle length. Real dairy processing wastewater and synthetic wastewater have been treated using three laboratory-scale IASBR units in a temperature controlled room. When the operational conditions were established, the units were seeded using sludge from a municipal wastewater treatment plant for the first experiment, and sludge from a dairy processing factory for the second and third experiment. In experiment three, the reactors were fed on real wastewater from the wastewater treatment plant at this dairy processing factory. These laboratory-scale systems will be used to demonstrate over time that the IASBR system is a consistent, viable option for treatment of dairy processing wastewater in this sector. In this study, the capacity of a biological system to remove both nitrogen and phosphorus within one reactor will be demonstrated. The initial operational parameters for a pilot-scale IASBR system will be derived from the results of the study.

Dominance of the genus Polaromonas in the microbial ecology of an Intermittently Aerated Sequencing Batch Reactor (IASBR) treating dairy processing wastewater under varying aeration rates.

In this Research Communication we investigate potential correlations between key bacterial groups and nutrient removal efficiency in an Intermittently Aerated Sequencing Batch Reactor (IASBR) treating synthetic dairy processing wastewater. Reactor aeration rates of 0·6 and 0·4 litre per minute (LPM) were applied to an 8 l laboratory scale system and the relative impacts on IASBR microbial community structure and orthophosphate (PO4-P) and ammonium (NH4-N) removal efficiencies compared. Aeration at 0·6 LPM over several sludge retention times (SRTs) resulted in approximately 92% removal efficiencies for both PO4-P and NH4-N. Biomass samples subjected to next-generation sequencing (NGS), 16S rRNA profiling revealed a concomitant enrichment of Polaromonas under 0·6 LPM conditions, up to ~50% relative abundance within the reactor biomass. The subsequent shift in reactor aeration to 0·4 LPM, over a period of 3 SRTs, resulted in markedly reduced nutrient removal efficiencies for PO4-P (50%) and NH4-N (45%). An 85·7% reduction in the genus level relative abundance of Polaromonas was observed under 0·4 LPM aeration conditions over the same period.

Assessing the environmental impact of the dairy processing industry in the Republic of Ireland.

This Research Communication describes the methodology used and the subsequent results obtained for an assessment of the environmental impact associated with the manufacture of dairy products in the Republic of Ireland. As the Irish dairy industry changes and grows, it is necessary to have a benchmark of the environmental performance of the sector if it is to remain sustainable in the future. In order to estimate the environmental impact, life cycle assessment has been implemented, which has been structured in accordance with the International Organisation for Standardisation guidelines. In this study, the environmental impact categories assessed are terrestrial acidification potential, cumulative energy demand, freshwater eutrophication potential, global warming potential, marine eutrophication potential and water depletion. The main Irish dairy products have been compared across these environmental impact categories in order to derive meaningful results. It is identified that packaging materials, particularly for infant formula, and energy usage, across each of the life cycle stages, should be targeted as these are the most significant contributors to the overall environmental impact.

DairyWater: striving for sustainability within the dairy processing industry in the Republic of Ireland.

This Review describes the objectives and methodology of the DairyWater project as it aims to aid the Irish dairy processing industry in achieving sustainability as it expands. With the abolition of European milk quotas in March 2015, the Republic of Ireland saw a surge in milk production. The DairyWater project was established in anticipation of this expansion of the Irish dairy sector in order to develop innovative solutions for the efficient management of water consumption, wastewater treatment and the resulting energy use within the country's dairy processing industry. Therefore, the project can be divided into three main thematic areas: dairy wastewater treatment technologies and microbial analysis, water re-use and rainwater harvesting and environmental assessment. In order to ensure the project remains as relevant as possible to the industry, a project advisory board containing key industry stakeholders has been established. To date, a number of large scale studies, using data obtained directly from the Irish dairy industry, have been performed. Additionally, pilot-scale wastewater treatment (intermittently aerated sequencing batch reactor) and tertiary treatment (flow-through pulsed ultraviolet system) technologies have been demonstrated within the project. Further details on selected aspects of the project are discussed in greater detail in the subsequent cluster of research communications.

Efficient treatment of dairy processing wastewater in a pilot scale Intermittently Aerated Sequencing Batch Reactor (IASBR).

This Research Communication describes the initial operation of a pilot-scale intermittently aerated sequencing batch reactor system, which is located at an Irish dairy processing factory. Laboratory-scale research has facilitated the design specifications and operational parameters necessary for the construction and running of a pilot-scale. Laboratory scale research was necessary prior to the pilot scale system to ensure high quality treatment and nutrient removal efficiencies. The pilot system operates with a hydraulic retention time of 4 d, a solids retention time of 16 d and a cycle length of 12 hours. There are 4 non-aeration and aeration phases within the system's react phase. This system has a 3000 l working volume, treating 375 l of wastewater per cycle, 750 l daily. The system was seeded from an aeration tank at the dairy processing factory where the unit is located. The system is operating with the goal to remove both nitrogen and phosphorus from the wastewater biologically, reducing the need for chemical treatment. Currently, the system is performing with high efficiency, treating the wastewater to an acceptable level according to the Irish Environmental Protection Agency for discharge into surrounding water bodies. Therefore, the initial removal results demonstrate this technology's suitability for the treatment of high strength dairy wastewaters.

Microbiological characterisation and impact of suspended solids on pathogen removal from wastewaters in dairy processing factories.

In this Research Communication we investigate the microbiological profile of 12 dairy wastewater streams from three contrasting Irish dairy processing factories to determine whether faecal indicators/pathogens were present and in turn, whether disinfection may be required for potential water reuse within the factory. Subsequently, the impact of suspended solids on the inactivation efficiency of Escherichia coli via two means of ultravoilet (UV) disinfection; flow-through pulsed UV (PUV) and continuous low pressure UV (LPUV) disinfection was analysed. Faecal indicators total coliforms and E. coli were detected in 10 out of the 12 samples collected at the dairy processing factories while pathogenic bacteria Listeria monocytogenes was detected in all samples collected at 2 out of the 3 factories. Salmonella spp. was undetected in all samples. The results also indicated that organic dairy wastewater solids had an impact on the performance efficiency of the PUV system and, to a lesser extent, the LPUV system. The findings indicate that the targeting of key pathogens would be required to enable wastewater reuse (and indeed effluent discharges if regulation continues to become more stringent) and that LPUV may offer a more robust disinfection method as it appears to be less susceptible to the presence of suspended solids.

Evaluation of dairy processing wastewater biotreatment in an IASBR system: Aeration rate impacts on performance and microbial ecology.

Dairy processing generates large volumes of wastewater that require extensive nutrient remediation prior to discharge. Significant commercial opportunities exist therefore for cost-effective biotechnologies capable of achieving this requirement. In this study the authors evaluated the use of intermittently aerated sequencing batch reactors, (IASBRs), as a single-tank biotreatment system for co-removal of COD, nitrogen and phosphorus from synthetic dairy processing wastewater. Variation of the IASBR aeration rates, (0.8, 0.6 and 0.4 L/min), had significant impacts on the respective nutrient removal efficiencies and underlying microbial diversity profiles. Aeration at 0.6 L/min was most effective and resulted in >90% co-removal of orthophosphate and ammonium. 16S rRNA based pyrosequencing of biomass DNA samples revealed the family Comamonadaceae was notably enriched (>80% relative abundance) under these conditions. In silico predictive metabolic modelling also identified Comamonadaceae as the major contributor of several known genes for nitrogen and phosphorus assimilation (nirK, nosZ, norB, ppK, ppX and phbC).

A Novel and Validated Protocol for Performing MIC Tests to Determine the Susceptibility of Piscirickettsia salmonis Isolates to Florfenicol and Oxytetracycline.

This paper presents a validated protocol, using a novel, specifically formulated medium, to perform broth microdilution antimicrobial susceptibility assays of the salmonid bacterial pathogen Piscirickettsia salmonis. The minimum inhibitory concentrations (MIC) for florfenicol and oxytetracycline against 58 P. salmonis isolates recovered from various outbreaks occurred in Chilean salmonid farms were determined using this protocol. Normalized resistance interpretation (NRI) analysis was applied to these data to calculate appropriate protocol-specific epidemiological cut-off values. These cut-off values allow the isolates to be categorized as either fully susceptible wild type (WT) members of this species, or as manifesting reduced susceptibility non-wild type (NWT). The distribution of MIC values of florfenicol was bimodal and the distribution of the normalized values for the putative WT observation had a standard deviation of 0.896 log2 µg mL-1. This analysis calculated a cut-off value of ≤0.25 µg mL-1 and categorized 33 (56%) of the isolates as manifesting reduced susceptibility to florfenicol. For the oxytetracycline MIC data the NRI analysis also treated the distribution as bimodal. The distribution of the normalized values for the putative WT observation had a standard deviation of 0.951 log2 µg mL-1. This analysis gave a cut-off value of ≤0.5 µg mL-1 and categorized five isolates (9%) as manifesting reduced susceptibility to oxytetracycline. The susceptibility testing protocol developed in this study was capable of generating MIC data from all the isolates tested. On the basis of the precision of the data it generated, and the degree of separation of values for WT and NWT it achieved, it is argued that this protocol has the performance characteristics necessary for it to be considered as a standard protocol.

Environmental impacts of milk powder and butter manufactured in the Republic of Ireland.

The abolition of the milk quota system that was in place in Europe was abolished in 2015, which instigated an immediate increase in milk production in many European countries. This increase will aid in addressing the world's ever growing demand for food, but will incur increased stresses on the environmental impact and sustainability of the dairy industry. In this study, an environmental life cycle assessment was performed in order to estimate the environmental impacts associated with the manufacture of milk powder and butter in the Republic of Ireland. A farm gate to processing factory gate analysis, which includes raw milk transportation, processing into each product and packaging, is assessed in this study. Operational data was obtained from 5 dairy processing factories that produce milk powder (4 of which also produce butter). Results for each environmental impact category are presented per kilogram of product. Energy consumption (raw milk transportation and on-site electrical and thermal energy usage) contributes, on average, 89% and 78% of the total global warming potential, for milk powder and butter respectively, for the life cycle stages assessed. Similarly, energy consumption contributes, on average, 86% and 96% of the total terrestrial acidification potential for milk powder and butter respectively, for these life cycle stages. Emissions associated with wastewater treatment contribute approximately 10% and 40% to the total freshwater eutrophication potential and marine eutrophication potential, respectively, for both milk powder and butter production. In addition, packaging materials also has a significant contribution to these environmental impact categories for butter production. Results were also presented for three milk powder products being manufactured by the factories surveyed: skim milk powder, whole milk powder and full fat milk powder. The analysis presented in this paper helps to identify opportunities to reduce the environmental impacts associated with post-farm processing of milk powder and butter.