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Accelerating abscission of macadamia nuts using ethephon: are there implications for nut quality?
Get PDFMacadamia is a valuable nut due to its high content of healthy monounsaturated fats, dietary fibre, antioxidants, and essential minerals such as magnesium-B and potassium. One of the major issues affecting industries around the globe is the delayed nut abscission and a prolonged and expensive harvest. A delay in harvesting also reduces the quality of the kernel. To address this challenge, ethephon is used to accelerate abscission, helping to prevent delays in harvesting. Ethephon can cause up to a 15-fold increase in nut abscission within 4 weeks compared to untreated trees. We provide a brief overview of the use of ethephon and its effects on nut quality. The major side-effects of ethephon used to manage macadamia harvesting are associated with ethylene, which is released from ethephon during the acceleration of plant senescence. This process impacts nut quality and shelf life by modulating lipid composition and nut biochemistry. Additionally, ethephon influences the appearance of the nut and the expression and regulation of specific plant genes. This review bridges the information gap between the application of ethephon for harvesting and its effects on the nut quality.National Research Foundation, Neurosciences Research FoundationThis work was funded by the National Research Foundation (NRF) of South Africa [Grant Number 142060].The Journal of Horticultural Science and Biotechnolog
Evaluating flow cytometric metrics for enhancing microbial monitoring in drinking water treatment processes
Get PDFFlow cytometry (FCM) offers a rapid method for bacterial detection in drinking water but faces challenges in terms of data analysis, particularly gating subjectivity. This study evaluates three metrics derived from the Intact Cell Count (ICC): High/Low Nucleic Acid (HNA/LNA) ratios, Bray–Curtis Dissimilarity Index (BCDI), and FCM fingerprints—to enhance microbial monitoring approaches across different water treatment and distribution stages. ICC provided a direct assessment of microbial load in high cell count scenarios, while HNA/LNA ratios were valuable during low microbial levels. BCDI effectively tracked microbial population changes throughout treatment processes. A lead–lag analysis revealed that ICC changes often precede or coincide with BCDI changes and lead changes in HNA/LNA ratios. FCM fingerprinting visualized spatial and temporal variations in microbial communities. Combining these FCM metrics improved microbial water quality assessment and supports approaches to optimise water treatment strategies from a microbial perspective.Engineering and Physical Sciences Research CouncilThe UK Engineering and Physical Sciences Research Council (EPSRC) and South-East Water funded the work through an Engineering Doctoral Training Award (grant number: EP/L015412/1) to Leila Claveau.Journal of Water Process Engineerin
Wave devouring propulsion for stabilizing floating wind turbine platform: experimental study
Get PDFWave Devouring Propulsion (WDP) is a green propulsion method that uses submerged foils to convert wave energy into thrust, serving both as an auxiliary propulsion system and as a stabilizer for maritime structures. This study highlights WDP's effectiveness in improving stability for semi-submersible offshore wind turbine platforms. Experiments on a 1:100 scaled model in regular and irregular head wave conditions were conducted in both free-floating conditions, and with a mooring system to validate WDP's effectiveness. Results show that the integrated foil design reduced mooring line tension by 41.07% compared to the design without foils in specific scenarios, suggesting a promising avenue for future research and application.Liang Yang acknowledges the support from the HEIF fund for the project ‘Novel Floating Wind Platform’, the Future Frontiers Fund (FFF) from Cranfield University and Cranfield Global Research Fund.Ocean Engineerin
MegaSat: feasibility of a modular and expandable geostationary platform for optimizing geo-slot allocations
Get PDFThe increasing congestion in geostationary orbit, driven by the growing demand for satellite-based services, presents significant challenges for efficient slot allocation. Addressing this issue, this paper presents a feasibility study of a modular and expandable geostationary platform designed to optimize orbital slot allocation. The proposed MegaSat platform offers a scalable solution by allowing multiple payloads to be launched and serviced over time, making efficient use of allocated GEO slots. Key features include an architecture for gradual expansion and integration of new payloads, and advanced propulsion systems for optimal positioning. The study explores the economic and operational benefits, demonstrating its potential to reduce costs and improve service lifetimes for satellite operators. Results
indicate that MegaSat can significantly enhance GEO slot utilization, providing a viable solution to the challenges posed by increasing congestion in geostationary orbit.75th International Astronautical Congress (IAC 2024
Interplay between wear and thermal expansion in 6082 aluminum: a simulation and experimental study
Get PDFThis study investigates how wear and thermal expansion interact in 6082 aluminum, utilizing a pin-on-disc tribometer and finite element analysis under diverse mechanical conditions. The findings show that thermal expansion reduces contact area by forming a protrusion at the contact interface. This interaction between wear and thermal expansion causes dynamic shifts in the contact region and pressure distribution, affecting the disc center and altering wear progression and temperature patterns. High thermal expansion shifts maximum wear from the contact center to outer regions, especially at higher speeds and loads. Without thermal expansion, wear-only conditions overestimate friction dissipation, resulting in a higher peak temperature. These results highlight the critical role of thermal expansion in shaping wear patterns and contact behavior in sliding applications. This research offers insights for optimizing tribological performance in 6082 aluminum, with potential applications in other materials.Applied Science
In-orbit system identification of a flexible satellite with variable mass using dual Unscented Kalman filters
Get PDFModern space mission concepts are increasingly dependent on the robust and reliable deployment of spacecraft with large appendages, such as antennas, booms or solar panels. Such deployment requires the ability to properly capture and control the coupled system dynamics, which requires accurate in-orbit system identification of the mass and structural properties. This paper utilises dual Unscented Kalman filters (DUKF) to develop an online system identification strategy that captures both the structural and mass properties, and the attitude and orbit dynamics. The dynamics of the flexible multibody problem are derived from the Lagrangian equations, with the flexible body characteristics modelled with finite element software. A genetic algorithm is used to optimise the accelerometer placement, and hence improve the DUKF performance. We demonstrate that this approach can accurately capture the coupled attitude, orbit, and structural dynamics, as well as being able to provide in-orbit updates for mass properties such as the moment of inertia. The methodology is explored for two illustrative cases: one in which the initial moment of inertia is incorrectly characterised, one in which the moment of inertia changes with time. In both cases, the DUKF approach captures both the system dynamics and the mass properties, which are captured with an error of less than 1%.Acta Astronautic
A study into the effect of Hull Configuration on the performance of floating solar PV structure
Get PDFAt present, energy transition is a reality in the journey towards achieving net zero emission. Among others, the development of floating solar photovoltaic (FPV) power plants is one of many possible renewable energy technologies that received considerable attention. One of the reasons for that is attributed to land acquisition which can lead to conflicts, whilst the use of sea is more flexible. Therefore, the development of floating solar PV situated at the near shore (later can be moved offshore) is promising particularly in order to withstand the harsh environment. The study aims to demonstrate such an innovative design of a floating structure and two types of hulls (monohull and twin-hull) are considered and focused on the seakeeping performance of the two bodies. BEM approach with Green-Function based on the 3-D diffraction panel method together with the use of the Joint North Sea Wave Project (JONSWAP) wave spectrum is carried out to accomplish the seakeeping characteristic. The final computational simulation results show that the twin-hull model has more advantages than the monohull design. The trend of the RAO pattern, response spectra, and significant response for heave and pitch motion represent only slight differences between the two proposed designs. However, substantial disparity emerges in roll motion, with the difference in response values in prevailing 0o -roll heading standing at 53%, 39%, 27%, and 18% for sea states 1 through 4, respectively. Moreover, in 45o wave heading (quartering sea) it demonstrates a slightly lower disparity compared to the 0o wave heading (following sea) through sea-state 1-4 standing for 50%, 37%, 24% and 16% respectively.The authors also acknowledge that this research was partly funded by the Innovate UK "Solar2Wave" project, under Grant Number 10048187.Journal of Advanced Research in Fluid Mechanics and Thermal Science
Knowledge extraction for additive manufacturing process via named entity recognition with LLMs
Get PDFThis paper proposes a novel NER framework, leveraging the advanced capabilities of Large Language Models (LLMs), to address the limitations of manually defined taxonomy. Our framework integrates the expert knowledge internalized in both academic materials and LLMs through retrieval-augmented generation (RAG) to automatically customize taxonomies for specific manufacturing processes and adopts two distinct strategies of using LLMs — In-Context Learning (ICL) and fine-tuning to complete manufacturing NER tasks with minimal training data. We demonstrate the framework efficiency through its superior ability to define precise taxonomies, identify and classify process-level entities related to the most popular additive manufacturing process fused deposition modeling (FDM) as case study, achieving a high F1 score of 0.9192.Directorate for Computer & Information Science & Engineering, United States Department of EnergyThis research is funded by the U.S. Department of Energy (DOE) Office of Manufacturing and Energy Supply Chains (DE-EE0009726). We acknowledge Prof. Larry Smarr and Prof. Thomas DeFanti from University of California San Diego for HyperCluster computing support of San Diego Supercomputer Center (SDSC) National Research Platform (NRP) Nautilus sponsored by the U.S. National Science Foundation (NSF) (2100237, 2120019).Robotics and Computer-Integrated Manufacturin
Proactive monitoring of changes in the microbial community structure in wastewater treatment bioreactors using phospholipid fatty acid analysis
Get PDFDiverse microbial community structures (MCS) in wastewater treatment plants (WWTPs) are vital for effectively removing nutrients and chemicals from wastewater. However, the regular monitoring of MCS in WWTP bioreactors remains unattractive owing to the skill and cost required for deploying modern microbial molecular techniques in the routine assessment of engineered systems. In contrast, low-resolution methods for assessing broad changes in the MCS, such as phospholipid fatty acid (PLFA) analysis, have been used effectively in soil studies for decades. Despite using PLFA analysis in soil remediation studies to capture the long-term effects of environmental changes on MCS, its application in WWTPs, where the microbial mass is dynamic and operational conditions are more fluid, remains limited. In this study, microbial communities in a controlled pilot plant and 12 full-scale activated sludge plants (ASPs) were surveyed over a two-year period using PLFA analysis. This study revealed that changes in the MCS in wastewater bioreactors could be detected using PLFA analysis. The MCS comprised 59 % Gram-negative and 9 % Gram-positive bacteria, 31 % fungi, and 1 % actinomycetes. The abundances of Gram-negative bacteria and fungi were strongly inversely correlated, with an R2 = 0.93, while the fatty acids cy17:0 and 16:1ω7c positively correlated (R2 = 0.869). Variations in temperature, solid retention time, and WWTP configuration significantly influenced the MCS in activated sludge reactors. This study showed that WWTP bioreactors can be routinely monitored using PLFA analysis, and changes in the bioreactor profile that may indicate imminent bioreactor failure can be identified.This research was funded by UK Water Industry Research.Engineering Microbiolog
CFD analysis on novel vertical axis wind turbine (VAWT)
Get PDFThe operation of vertical axis wind turbines (VAWTs) to generate low-carbon electricity is growing in popularity. Their advantages over the widely used horizontal axis wind turbine (HAWT) include their low tip speed, which reduces noise, and their cost-effective installation and maintenance. A Farrah turbine equipped with 12 blades was designed to enhance performance and was recently the subject of experimental investigation. However, little research has been focused on turbine configurations with more than three blades. The objective of this study is to employ numerical methods to analyse the performance of the Farrah wind turbine and to validate the findings in comparison with experimental results. The investigated blade pitch angles included both positive and negative angles of 7, 15, 20 and 40 degrees. The k-ω SST model with the sliding mesh technique was used to perform simulations of a 14.4 million element unstructured mesh. Comparable trends of power output results in the experimental investigation were obtained and the assumptions of mechanical losses discussed. Wake recovery was determined at an approximate distance of nine times the turbine diameter. Two large complex quasi-symmetric vortical structures were observed between positive and negative blade pitch angles, located in the near wake region of the turbine and remaining present throughout its rotation. It is demonstrated that a number of recognised vortical structures are transferred towards the wake region, further contributing to its formation. Additional notable vortical formations are examined, along with a recirculation zone located in the turbine’s core, which is described to exhibit quasi-symmetric behaviour between positive and negative rotations.Machine