Ocean wave energy is one of the world's most powerful forms of energy and the energy density in ocean waves is the highest among renewable energy sources. Wave energy converters are employed to ...harness this energy and convert it into usable electrical energy. However, in order to efficiently extract the energy, the wave energy converter must be optimised in the design stage. Therefore, in this paper, a methodology is presented which aims to optimise the structural geometric configuration of the device to maximise the average power extraction from its intended deployment site. Furthermore, a case study of the Atlantic marine energy test site, off the west coast of Ireland, is undertaken in order to demonstrate the methodology. Using the average annual wave energy spectrum at this site as the input, the optimum structural geometric configuration was established, along with an analysis of the optimum configuration for different radius devices. In addition, the optimum damping coefficient of the PTO mechanism is determined and the total mean absorbed power for the structure at the site over the entire scatter diagram of data is calculated.
•A methodology to optimise the geometric configuration of wave energy converters is described.•The device is designed to maximise the average power extraction from its intended deployment site.•A case study that develops an optimised device, dependent on the deployment site, is presented.•The response of the optimised device to realistic ocean waves and the power harnessed are calculated.
As the world shifts to using renewable sources of energy, wind energy has been established as one of the leading forms of renewable energy. As the requirement for wind energy increases, so too does ...the size of the turbines themselves, where the latest turbines are 10 MW with a turbine diameter in excess of 190 m. The design and manufacture of the blades for these turbines will be critical if they are to last for the design life, where the accuracy of the numerical models used in the design process is paramount. Therefore, in this paper, three independent numerical models have been created using three available finite element method packages—ABAQUS, ANSYS, and CalculiX—and the results were compiled. Following this, the accuracy of the models has been evaluated and validated against the results from an experimental testing campaign. In order to complete the study, a 13 m full-scale wind turbine blade has been used, which has been subjected to static testing in both the edgewise and flapwise directions. The results from this testing campaign, along with the blade mass and natural frequencies, have been compared to the results from the independent numerical models. The differences in the models, along with other sources of error, have been discussed, which includes recommendations on the development of accurate numerical models.
The education sector is an important component of the UK's net zero strategy, in terms of both the carbon footprint of school buildings and operations, and the opportunities to teach about ...environmental issues and empower climate action. However, school sustainability is often narrowly defined around individual choices and behaviours by different school stakeholders, rather than the broader patterns of social practices. This qualitative study of secondary schools in England involved stakeholder interviews and student focus groups at twelve schools in Greater London and the Thames Valley Region (Berkshire, Buckinghamshire, Oxfordshire) where 142 people participated in this research, including teachers, students, parents, governors and school staff (leadership, facilities, finance). School sustainability was explored through the lens of social practice theory, and three bundles of practices and arrangements were identified: teaching/learning, catering/eating, movement/travel. Whole-school approaches to sustainability were reframed through the semantic, material and social spaces identified in the theory of practice architectures. School sustainability requires a substantial investment into retrofitting school buildings, but it also needs to be woven in the culture of a school – firmly on the agenda of the governors and leadership team, parallel to an issue like safeguarding – and supported by clearly identified roles and relationships in each institution. This research is aimed at environmental educators and researchers wishing to apply insights from social theory to develop more effective whole-school approaches to sustainability. This research also reveals a potential divide between state and private schools when it comes to environmental education, empowerment and action.
•The sayings, doings and relatings of sustainable school practice architectures were explored at secondary schools in England.•This research identified three bundles of practices related to teaching/learning, catering/eating and movement/travel.•The semantic, material and relational dimensions of practice architectures complement whole-school sustainability.
As drone technology grows in popularity, its application to automate aspects of society is increasing at a similar rate, where drones are now being trialled for delivering payloads over short ...distances. In order to progress the technology, 3D composite printing is being used to develop complicated parts for improved aerodynamic design that can be produced efficiently, where the resultant composite part has high specific strength and rigidity. This article reports 3D printing of high specific strength, high-temperature Polyamide 6 (Onyx), continuous glass-fibre reinforced Onyx, and carbon-fibre reinforced Onyx composites and characterising their mechanical and fracture behaviour. The Onyx + CF composites displayed up to 1243 % and 1344 % improvement in Young's modulus and tensile strength over neat Onyx samples. The flexural strength of Onyx + CF samples was up to 316.6 % higher than the flexural strength of the neat Onyx sample. SEM micrographs showed a strong bond between the hydration products and the carbon fibres, increasing their tensile and flexural strengths by preventing micro-crack propagation through fibre pull-out and breaking. The statistical analysis was conducted to ensure the validity of the results for the population and establish stress-strain relations, along with estimating errors. In addition, the carbon-fibre-reinforced Onyx composite was compared with commercially used alternatives for producing drone components. Finally, a finite element model was developed using a numerical homogenisation approach and validated to predict the tensile and flexural behaviour of Onyx and carbon-fibre reinforced Onyx samples. This study provides a direction for the next generation of drone manufacturers.
This paper presents a validated protocol, using a novel, specifically formulated medium, to perform broth microdilution antimicrobial susceptibility assays of the salmonid bacterial pathogen
. The ...minimum inhibitory concentrations (MIC) for florfenicol and oxytetracycline against 58
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 log
μg mL
. This analysis calculated a cut-off value of ≤0.25 μg mL
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 log
μg mL
. This analysis gave a cut-off value of ≤0.5 μg mL
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.
•Dairy processing wastewater biotreatment using IASBR technology is proposed.•Minor (0.2 LPM) aeration rate variations heavily influenced efficiency and ecology.•Optimal nutrient removal efficiencies ...(≥92%) achieved under 0.6LPM aeration rate.•Comamonadaceae stably enriched in reactor biomass (>80% relative abundance).•Comamonadaceae top contributor of nitrogen and phosphorus assimilation genes.
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).
Drone technology is widely available and is rapidly becoming a crucial instrument in the functions of businesses and government agencies worldwide. The demand for delivery services is accelerating ...particularly since the Covid-19 pandemic. Both companies and customers want these services to be efficient, timely, safe, and sustainable, but these are major challenges. Last-mile delivery by lightweight short-range drones has the potential to address these challenges. However, there is a lack of consistency and transparency in assessing and reporting the sustainability of last-mile delivery services and drones. This paper critically reviews published papers on Life Cycle Assessments of drones to date. The study reveals a lack of comprehensive studies, and a need to examine composite and battery manufacturing developments and provides key considerations for future study development.
Graphical Abstract
Climate change is an ever growing issue and a major concem worldwide. Both producers and processors need to address the issue now by reducing, their carbon footprint. Additionally, if Ireland is to ...meet their climate and energy targets, as outlined in Food Harvest 2020, which outlines a range ot objectives for the Irish agricultural sector, the efficient use of resources and fuels within the industry will need to be increased. In Ireland, agriculture accounts for 29.2% of the total greenhouse gas powder, is examined in order to estimate the global warming potential （GWP） associated with its manufacture using life cycle assessment. A cradle-to-processing factory gate analysis, which includes raw milk production, raw milk transportation to the processmg tactory, its processing into eacla product and product packaging, is assessed in this study using data collected circa 2013. The factories surveyed processed approximately 24% of the total raw milk processed in the Republic of Ireland in 2013, which was 5.83 billion liter. The average total GWP associated with the manufacture of milk powder is 9.731 kg CO2eq·kg^-1 milk powder, which has a standard deviation of 2.26 kg CO2eq·kg^-1 milk powder, for the life cycle stages analyzed in this study. The most significant contributor to GWP is raw milk production （84%）, followed by dairy processing （14%）, with the remainder of the life cycle stages contributing approximately 2%.
One of the main stages in the design of wave energy converters (WEC's) is the numerical modelling of a given converter. In this paper, the numerical simulation of both linear deep water waves and ...linear waves for the finite depth case are explored using computational fluid dynamics (CFD), to aid in this design stage. The CFD software package described in this paper is the commercial finite volume package ANSYS CFX (Release 12.1). The results of parametric studies, which were performed in order to optimise the CFD model, are detailed and a guide to creating a model that produces the desired waves is presented. The model was validated in two ways: (a) the wave created was compared to wavemaker theory (WMT) and (b) the water particle velocity and elevation of the wave was compared to linear, Airy, wave theory (LWT) for deep water waves. It was also found that wave generation in ANSYS CFX using a flap-type wavemaker was restricted to a low normalised wavenumber, k0h. In order to increase this restriction, the hinge of the wavemaker was raised and, with this alteration, it is possible to generate deep water linear waves. A case study of a real world application of wave–structure interaction, employing this methodology, is also explored.
► A methodology to generating linear waves in a numerical wave tank is described. ► An optimised model, depending on the period of the desired waves, is presented. ► The model was validated by comparing to wavemaker theory and Airy wave theory. ► Wavemaker theory is expanded to allow for a flap, which is not hinged at the base. ► The wave–structure interaction on a floating cylinder is modelled.
Dateline Soweto documents the working lives of black South African reporters caught between the mistrust of militant blacks, police harrassment, and white editors who--fearing government ...disapproval--may not print the stories these reporters risk their lives to get. William Finnegan revisited several of these reporters during the May 1994 election and describes their post-apartheid working experience in a new preface and epilogue. This title is part of UC Press's Voices Revived program, which commemorates University of California Press's mission to seek out and cultivate the brightest minds and give them voice, reach, and impact. Drawing on a backlist dating to 1893, Voices Revived makes high-quality, peer-reviewed scholarship accessible once again using print-on-demand technology. This title was originally published in 1995. Dateline Soweto documents the working lives of black South African reporters caught between the mistrust of militant blacks, police harrassment, and white editors who--fearing government disapproval--may not print the stories these reporters risk the.
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