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Germination response of South African cannabis landraces to accelerated aging: implications for seed storage
Get PDFThis study investigated the impact of accelerated aging on seed germination in five South African cannabis landraces: Ladysmith Ugwayi wesiZulu (‘L1’) and Iswazi (‘L2’), Bergville Natal (‘B2’) and Ugwayi wesiZulu (‘B1’), and Msinga Ugwayi wesiZulu (M1). Seeds were subjected to aging at 42 °C for 0 (control), 24, 48, 72, 96, and 120 hours. Seed viability assessed using a tetrazolium chloride (TTC) test, electrolyte conductivity, pH, and water activity were measured over five days. Germination tests were conducted at 30/25°C in Petri dishes in the laboratory and validated in a greenhouse, with daily recording of germination percentage (GP), germination rate index (GRI), and coefficient of velocity of germination (CVG). Accelerated aging significantly (p < 0.05) reduced seed viability, GP, GRI, and CVG while increasing electrolyte leakage and water activity. Landrace responses varied with ‘B1’ having maintained the highest viability (100% unaged, 94.41% after 120 hours), whereas ‘M1’ showed the lowest (70.63% after aging). Electrolyte conductivity was highest in ‘M1’ (393.2 μS cm-1 g-1 after 120 hours), while ‘L2’ exhibited the highest water activity (0.724 after 120 hours). Germination declined significantly under prolonged aging, with ‘L2’ and ‘B2’ exhibiting over 50% reductions in GP. The findings demonstrate that accelerated aging impairs seed quality through electrolyte leakage and moisture uptake demonstrated by water activity, with landrace-dependent sensitivity. These results emphasize the need for controlled storage to preserve cannabis seed viability and germination performance, particularly under conditions of elevated temperature and humidity common to many smallholder farming systems.This research was funded by Moses Kotane Institute.Biocatalysis and Agricultural Biotechnolog
Influence of sliding direction relative to layer orientation on tribological performance, noise, and stability in 3D-printed ABS components
Get PDFThe tribological performance of 3D-printed ABS components is influenced by layer orientation, yet its effects on friction, wear, noise, and system stability remain underexplored. This study investigates how the angle between sliding direction and layer lines (0°, ± 45°, 90°) impacts these properties in FDM-printed ABS. Pin-on-disc tests (10–20 N loads, 0.314–0.628 m/s speeds) and modeling (FEM for wear and temperature, lumped-parameter for stability) were conducted. The 90° orientation showed the highest coefficient of friction (COF) due to mechanical interlocking but the lowest wear, while the 0° orientation had the lower COF and highest wear from interlayer shear. The −45° orientation produced the most noise due to debris-induced stick-slip, while the 45° orientation generated the least. FEM wear predictions aligned well with experiments (<7 % error), but noise predictions had higher errors (up to 15 %). Increased wear depth raised vibration frequencies, and larger static-kinetic COF differences increased instability.Tribology Internationa
Comparative life cycle assessment of swarf cleaning methods for sustainable manufacturing
Get PDFThe metal manufacturing industry faces significant environmental challenges due to high energy consumption and waste production. This study critically analyzes two advanced swarf cleaning methods including supercritical CO2 cleaning and Cryoclean to evaluate their environmental impacts. Using Life Cycle Assessment (LCA), the research compares these methods to determine their effectiveness in reducing CO2 emissions and overall environmental impact. The results reveal that Cryoclean is the preferred method, slightly outperforming supercritical CO2 cleaning in minimizing carbon emissions and ecosystem damage. This makes Cryoclean the more sustainable option for most industrial applications requiring effective, residue-free cleaning. Specifically, Cryoclean reduced CO2 emissions by approximately 5% compared to supercritical CO2 cleaning. The study also highlights the energy and resource efficiency of these methods, emphasizing their role in promoting sustainable manufacturing practices. By providing a detailed comparison of these cleaning processes, the study offers valuable insights into optimizing swarf recycling, thereby supporting the global shift towards more sustainable industrial practices. This research underscores the importance of adopting efficient swarf cleaning technologies to enhance the sustainability of metal manufacturing and meet environmental targets.The authors acknowledge funding from the UK EPSRC project Sustainable Additive Manufacturing EP/W01906X/1.Procedia CIR
A multi-dimensional machine learning framework for superior propeller design choices
Get PDFIn this study, PropAI is presented, which is a scalable, multi-dimensional surrogate modelling framework for propeller performance prediction that compiles a large 5D baseline database and couples it to a KD-tree Gaussian radial-basis-function (RBF) interpolator. A full-factorial sweep over five design parameters (rotational speed, freestream velocity, blade pitch, diameter, and number of blades) yields 88,540 operating points evaluated via low-fidelity BEMT in QBlade. The trained surrogate reproduces these data with near-machine precision (global RMSE = 6.2e-4, MAE = 1.0e-5, R2 = 1.000), and parity plots of predicted vs true thrust and power lie essentially on the 45 deg line (1:1 line). Cross-validation of leave-one-out (LOO) errors confirms excellent generalisation, with both thrust and power below 0.6% of full-scale output. Integrated with an UNSGA‑III optimiser, the model performs multi-objective optimisation of thrust, power, and thrust-to-power ratio, producing Pareto fronts that reveal the trade-offs among these metrics. This lightweight, gradient-capable surrogate enables rapid design-space exploration (e.g. via 1D/2D response slices, pair-plots, parallel coordinates) and provides insight into parametric interactions.AIAA Aviation Forum and Ascend 202
Future-proofing cities against negative city mobility and public health impacts of impending natural hazards: a system dynamics modelling study
Get PDFBACKGROUND: The world faces increasing risk from more frequent and larger scale natural hazards, including infectious disease outbreaks (IDOs) and climate change-related extreme weather events (EWEs). These natural hazards are expected to have adverse mobility and public health impacts, with people living in cities especially vulnerable. Little is known about how transport systems can be optimally designed to make cities more resilient to these hazards. Our aim was to investigate how cities' transport systems, and their resulting mobility patterns, affect their capabilities to mitigate mobility and health impacts of future large-scale IDOs and EWEs.
METHODS: System dynamics modelling was used to investigate how different city mobility scenarios can affect the health and mobility impacts of four plausible future IDO and EWE (flooding) shocks in three cities: Belfast, UK; Belo Horizonte, Brazil; and Delhi, India. Three city mobility scenarios with incremental degrees of modal shift towards active travel (private motor vehicle volume reduced to 50% and 20% of total road trip volume in vision 1 and 2, and motor vehicle volume [including buses] reduced to 20% of total road trip volume in vision 3) were tested. For each city and each IDO and EWE shock, we estimated the percentage of deaths prevented in visions 1, 2, and 3, relative to the reference scenario, as well as changes in mode share over time.
FINDINGS: In all scenarios, all cities showed reduced susceptibility to flooding, with 4-50% of deaths potentially prevented, depending on case city, city mobility, and EWE scenario. The more ambitious the transition towards healthier city mobility patterns, the greater the resilience against flooding. Only vision 3 (the most ambitious transition) showed reduced vulnerability to IDOs, with 6-19% of deaths potentially prevented. Evolution of mode shares varied greatly across cities and mobility scenarios under the IDO shocks.
INTERPRETATION: Our results emphasise the importance of well designed, forward-thinking urban transport systems that make cities more resilient and reduce the impact of future public health-related and climate-related threats.
FUNDING: UK Prevention Research Partnership, UK Economic and Social Research Council, UK Medical Research Council, UK National Institute for Health and Care Research, Australian Research Council, Australian National Health and Medical Research Council, and Health and Social Care Research and Development Office Northern Ireland.Economic and Social Research Council, UK Research and Innovation, Medical Research Council, Australian Research Council, National Health and Medical Research Council, National Institute for Health and Care ResearchThe Lancet Planetary Healt
A critical review of liquid, low toxicity chemical warfare agent simulants: enhancing accuracy, safety, and methodological approaches for sampling
Get PDFThe use of simulants is a crucial aspect of studying the behaviour and effects of chemical warfare agents (CWAs) and toxic industrial chemicals (TICs) without the inherent dangers associated with handling and utilising the actual hazardous substances. This review assesses the selection and application of simulants for different classes of CWAs, including nerve agents such as soman, V agents and blister agents such as sulphur and nitrogen mustards. Several simulants were examined, including diethyl malonate, malathion, methyl salicylate, and di (propylene glycol) monomethyl ether, to ascertain their structural and physiochemical properties, yet present minimal toxicity risks. A key insight from this review is the importance of aligning simulant physicochemical properties, such as hydrophobicity, volatility and solubility to those of CWAs. This ensures data relevancy in sampling accuracy and method validation. Our findings demonstrate the efficacy of utilising multiple simulants to model complex interactions within different environmental and forensic matrices, thereby enhancing the precision and reliability of detection and verification procedures. By concentrating on liquid-based simulants and excluding gaseous and solid agents, this review offers a focused assessment of existing sampling methodologies for liquid CWAs in field conditions. It concludes by proposing a unified approach to sampling standards that mitigates the risk with the objective of enhancing the practicality and reliability of detection methods while ensuring personnel safety. Furthermore, this review provides crucial insights for developing robust, field-deployable CWA sampling strategies that strike a balance between accuracy, accessibility and low toxicity.Journal of Hazardous Material
Effects of Reynolds number and layout on aerodynamic and heat transfer characteristics of an aluminum sheet treated in a gas-cushion furnace
No full textHeat treatment of an aluminum sheet through a gas-cushion furnace is numerically investigated. The sheet of 0.6 mm thick was suspended due to simultaneous impingement of upward and downward gas jets. Effects of Reynolds number (Re = 8,000–32,000) and upper/lower distance ratio (du/dl = 3:5, 1:1, 5:3) on flow and heat transfer characteristics were investigated, along with the structural characteristics of the sheet. The validation of the numerical results was implemented though experimental data. The results indicate that an increase in Re leads to an increase in circulating flow intensity in the gas-cushion furnace, due to an increase in the peak value of Nusselt number (Nu). However, the variation of Re imposes an insignificant effect on the pressure coefficient distribution over the sheet. At Re = 24,000, an upward deformation is evidenced at the middle part of the sheet. As Re decreases to 16,000, relatively slight downward deformation appears at the middle part of the sheet. At an upper/lower distance ratio of 3:5, a uniform pressure distribution is obtained at the lower surface of the sheet. Furthermore, the near-wall flow in the middle part of the sheet brings benefits, and such a layout is responsible for high average temperature of the sheet.The authors are grateful for the financial support from Priority Academic Program Development of Jiangsu Higher Education Institutions of China (PAPD) and Wuxi Science and Technology Development Fund (Grant No. G20212030).Thermal Science and Engineering Progres
Development of soiling process characterisation methods for solar mirrors, for analysing mirror cleaning processes
No full textSansom, Christopher L. - Associate Supervisor - University of Derby
Schiller, Tara - Associate Supervisor - University of WarwickConcentrated Solar Power has the potential to provide power for the developing
global economies towards a sustainable future. This solar radiation-based
technology, reflects the radiation received by a solar mirror onto a receiver device
which absorbs heat. Maintenance is required to keep the solar mirrors clean, and
remove airborne particulate matter that settles on the mirror, which has an impact
on the solar collector efficiency. Constant research to optimize cleaning methods
and cleaning–strategies is paramount.
An artificial soiling test rig and soiling methods were developed, which are
capable of simulating repeatable soiling events and to specific soiling load.
These features are necessary to simulate cleaning cycles with a period of several
days. The developed test rig has a capability to provide a minimum soiling load
of 0.25g/m² and has a constant error of 16%. Repeatable soiling tests were
carried out up to 10 times.
Extensive soiling experiments with two soiling materials (silt material and ground
taken material from Almeria, Spain) and numerical simulation have revealed the
exponential nature of the soiling process. An empirical model was formulated,
which calculates specular reflectance, and includes material intrinsic parameters
and soiling load data. This model highlighted the fact that compared to a linear
model, between 7-20% lower soiling load is predicted, which potentially has a
positive influence on cleaning cycles and therefore the costs attributed to them.
A simulation series of a 10day cleaning cycles, which includes repeatable soiling
and condensation events, used the artificial soiling test rig and a cooling plate
located in a dry chamber. The adhesion effect (particle caking and capillary
aging) were analysed by a centrifuge and the coverage ratio of the mirror samples
before and after the experiments were calculated. It was noted that the
repeatable soiling test (soiling and condensation) had a visible difference
compared to the one-off soiling and condensation test series.
The experimental modelling work will help to improve the considerable
maintenance effort involved in mirror cleaning in solar field operations.Engineering and Physical Sciences Research Council (EPSRC)EngD in Sustainable Materials and Manufacturin
A novel Ku‐band waveguide piezo‐electric air gap capacitor using a single tuning element
Get PDFIn this work, a tuning element with controllable air gap integrated and implemented in a rectangular Ku‐band WR62 waveguide is presented. The proposed tuning element concept, consists of two, top and bottom, thin conductive parallelepiped arms, which are placed in the middle of the rectangular waveguide structure. The bottom arm is bending to control the gap width (w) between the two arms, whereas the second arm is fixed. The curvature of the bending arm is controlled by a piezo‐electric actuator, which affects the phase shift of the re‐scattered E‐field at the output port. The tuning element was designed with a 5% bandwidth centred at 15 GHz. The compact size, low‐cost and the easy‐to‐manufacture proposed design offers a considerable phase shift with very low insertion loss, given its electrical size and operational waveband. A prototype, for the distinct frequency band, has been manufactured and measured. The same prototype has been simulated in ANSYS HFSS. The numerical results will be later used to validate the actual electromechanical prototype.The work was funded by Cranfield University internally.IET Microwaves, Antennas & Propagatio
Social sensing a volcanic eruption: application to Kīlauea, 2018
Get PDFAbstract. Protecting lives and livelihoods during volcanic eruptions is the key challenge in volcanology, conducted primarily by volcano monitoring and emergency management organisations, but it is complicated by scarce knowledge of how communities respond in times of crisis. Social sensing is a rapidly developing practice that can be adapted for volcanology. Here we use social sensing of Twitter (currently known as X) posts to track changes in social action and reaction throughout the 2018 eruption of Kīlauea on the island of Hawai`i. The volume of relevant posts very rapidly increases in early May, coincident with the beginning of the eruption; automated sentiment analysis shows a simultaneous shift towards more negative emotions being expressed in post text. Substantial negative trends in sentiment are evident in reaction to high-impact events, including the destruction of a popular residential area and injuries sustained by tourists viewing the eruption. Topics of local Twitter conversation reveal societal actions, including the sharing of hazard warnings, mitigation actions, and aid announcements. Temporal trends in societal actions reflect patterns in volcanic activity (e.g. the peak and waning of eruptive activity), civil protection actions (e.g. risk mitigation actions and the communication of official warnings), and socioeconomic pressures (e.g. the destruction of homes). Local tweets detailing eruption damage and disruption display a similar temporal trend to independent estimates of the number of buildings in contact with lava. We show how hazard and risk information is discussed and reacted to on Twitter, which helps inform our understanding of community response actions and aids situational awareness, and outline how our approach could be adapted for use in real time.Engineering and Physical Sciences Research Council; NE/X013944/1Natural Hazards and Earth System Science