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Exploring metal extraction potential from historical metallurgical sites and waste deposits using solvometallurgical and hydrometallurgical processes.
Get PDFMetalliferous waste from past metallurgical sites present significant environmental risks yet
provide opportunities for metal extraction and recovery to supplement global demands in the
shift towards renewable technologies. Characterising site conditions, metal specificity of green
solvents and chelators, and an initial assessment of operating condition are required to develop
these approaches into a commercial setting. This study evaluates the efficacy of solvo- and
hydro-metallurgical approaches in extracting metals from real-world metalliferous waste.
Specifically, it examines the performance of green deep eutectic solvents (DES) and chelating
agents (CA) on blast oxide slag dust (BOS-D) and goethite, by-products of iron smelting and
zinc refinery processes, respectively. Through batch tests and column studies, the impact of
varying operational conditions, including molar ratio for DES and pH for CA were assessed.
The results were used to inform sequential bioleaching to solvo- or hydroleaching tests to
investigate the potential of hybrid extraction processes. The extraction efficiencies across
batch, column and the sequential study from BOS-D were compared against a commercial
chelating agent ethylenediaminetetraacetic acid (EDTA). DES extracted 60% more of the total
metal load compared to CA and EDTA from BOS-D in batch tests. When applied to goethite,
CA extracted 70% more of the total metal load than DES in batch tests. There was a 1%
difference in metal extraction between DES and CA from BOS-D and 2 % from goethite in the
column study. EDTA extracted the same or up to 15% more of the total metal load than DES
and up to 18% than CA in the column study. The sequential study demonstrated that DES and
CA have minimal influence in metal extraction under the operational conditions used in earlier
batch tests, when applied to the residue after bioleaching extraction using Acidithiobacillus
ferrooxidans. The extraction of the total metal load was improved by 4% using CA. The
findings of this study demonstrate that CA and DES can extract a robust suite of metals from
real metalliferous wastes. In BOS-D batch and column tests, analysis of metal group selectivity
showed that DES had greater extraction than EDTA across all metal groups except rare earth
lanthanides. In BOS-D batch studies, EDTA had greater extraction than CA across all metal
groups except alkaline metals, but column studies showed that CA had greater extraction than
EDTA across all metal groups except alkaline metals. This provides evidence for a robust metal
extraction process and could improve the suite of extractable metals, providing sustainable
alternatives in metal supply chains. The understanding of these extraction processes will be
improved through, optimisation of more physical controls e.g., temperature, agitation, and
further optimisation of the initial chemical conditions to improve metal extraction efficiencies,
metal selection and potential revenue generation.PhD in Energy and Powe
Wave velocity analysis and repeatability of artificial acoustic emission in homogeneous materials: steel and aluminium plates
No full textIn this study, wave velocity calculations and the repeatability of the Pencil Lead Break (PLB) test were examined through two use-cases involving homogeneous materials: a 5mm aluminium plate and a 2mm steel plate. The PLB test is a widely used and straightforward method for generating artificial acoustic emissions. Ensuring its repeatability is essential for reliable signal processing in acoustic emission (AE)-based analysis. PLB tests were repeated under controlled conditions, and the resulting AE waveforms were analysed using Fast Fourier Transform (FFT) and Continuous Wavelet Transform (CWT). Time-of-arrival (TOA) values were extracted to calculate wave velocities using known distances between the source and sensors. The measured velocities—approximately 5100m/s for aluminium and 5700m/s for steel—were consistent with expected Lamb wave mode behaviour. The research emphasises the importance of applying consistent PLB force to produce clear waveform characteristics and valid TOA-based velocity estimates. These findings support the validity of TOAbased wave velocity measurement methods for thin homogeneous plates and establish a foundation for extending similar methodologies to more complex materials and acoustic emission scenarios.The authors gratefully acknowledge the support from Cranfield University and the Centre for Life-cycle Engineering and Management21st International Conference on Condition Monitoring and Asset Managemen
Real-time CO2 production monitoring in stored oats as an indicator of type A trichothecenes and ochratoxin A contamination under simulated environmental conditions
Get PDFGrain industries are interested in an integrated approach to in-silo grain quality and safety management using carbon dioxide (CO2) measurement with temperature and moisture monitoring. Our study investigates if CO2 production could predict mycotoxin production (T-2 toxin, HT-2 toxin, its glucoside, and ochratoxin A (OTA)) and identify storage conditions exceeding legislative limits in stored oats for the first time. The influence of water activity (aw) levels (0.70–0.95 aw), temperature (15 and 20 °C), and storage duration on (a) Fusarium populations, (b) CO2 respiration rates (RRs), and (c) mycotoxin concentrations in stored oats was examined. One hundred and twenty samples were analysed for multiple mycotoxins by LC-MS/MS. Substantial differences were found in the RRs of oats at ≥0.90 aw at both temperatures. A moderate positive correlation between CO2 and mycotoxins was noticed and mycotoxins exceeded their limits at ≥0.90 aw (22% moisture content) when RR ≥ 25 µg CO2 kg−1 h−1. This knowledge forms the basis for developing decision support systems for improving oats’ storage management.This research was funded by the United Kingdom Research and Innovation (UKRI), the Biotechnology and Biological Sciences Research Council (BBSRC), and the FoodBioSystem Doctoral Training Programme (FBSDTP); grant reference: BB/T008776/1.Toxin
Unique osteological evidence for human-animal gladiatorial combat in Roman Britain
Get PDFThe spectacle of Roman gladiatorial combat captures the public imagination and elicits significant scholarly interest. Skeletal evidence associated with gladiatorial combat is rare, with most evidence deriving from written or visual sources. A single skeleton from a Roman cemetery outside of York where gladiators arguably were buried presented with unusual lesions. Investigation, including comparative work from modern zoological institutions, has demonstrated that these marks originate from large cat scavenging. Thus, we present the first physical evidence for human-animal gladiatorial combat from the Roman period seen anywhere in Europe.PLOS ON
Impacts of urease inhibitors on nitrogen assimilation in wheat and on reducing nitrogen losses
Get PDFA major global challenge for the 21st century is to ensure food security and sustainable
development while limiting the adverse impact of agricultural reactive nitrogen (Nr)
pollution and global warming greenhouse gas emissions (GHG). Climate change
mitigation and adaptation strategies, with varying effectiveness, have been implemented
across different regions in this perspective. The use of enhanced efficiency N fertilisers
(EEF) in agriculture is a potential management strategy towards this aim, with
documented benefits but with existing knowledge gaps. In this thesis, the efficacy of EEF,
particularly urease inhibitors (UI), was determined under warmer, dryer climatic
conditions as are expected to occur more frequently under climate change scenarios.
Additionally, the potential of UI to improve nitrogen use efficiency (NUE) and enhance
the tolerance of wheat varieties to drought stress at different N rates was evaluated, as
well as the influence of UI on plant N assimilation and potential contribution to nitrous
oxide (N₂O) emissions. The effects of high soil temperature (>25℃) and low soil
moisture (<40% water filled pore space; WFPS) on emissions of ammonia (NH₃ ) and
N₂O following application of urea to soil was assessed, and the efficacy of UI in reducing
N losses. The findings suggest that treatment of urea with UI effectively reduces NH₃
losses at temperatures reaching 35℃, although overall effectiveness decreases with
increasing temperature and low soil moisture conditions. Nitrous oxide emission was not
influenced by the presence of UI but was high at soil moistures <60% WFPS. Nitrous
oxide emission was also measured from wheat plants grown in soil and in a hydroponic
system under low (7 kg ha⁻¹) and high N (70 kg ha⁻¹) conditions. Plants emitted more N₂O
under low N growth conditions when supplied with additional potassium nitrate
compared with those supplied with urea treated with UI. However, insufficient evidence
was obtained from the hydroponic experiment to confirm plant N₂O formation through
nitrate assimilation pathways, other than its overall contribution to N₂O emissions.
Furthermore, when applied to plants under drought stressed conditions, UI did not
enhance wheat tolerance to drought or increase yield and NUE. Nitrogen assimilation was
influence by UI, particularly leaf urea concentration which increased in the presence of
UI. Similarly, application of urea included with UI at a high N rate (180 kg ha⁻¹) resulted
in lower wheat biomass and yield. Varietal differences were also observed in plant N₂O
emission, drought tolerance and NUE. Overall, the findings support the use of UI as a Nr
mitigation strategy under warm and dry conditions; however, for increased NUE and
yield, appropriate fertiliser and crop management, specific to local conditions may be
needed.PhD in Environment and Agrifoo
Correction: RANS/LES and LBM/VLES aero-acoustic analysis of weapon bays at transonic Mach number
No full textNumerical aero-acoustic analysis was conducted on a weapon bay of a generic aircraft model using two conceptually different solvers, one based on the Navier-Stokes equations, the other based on the lattice-Boltzmann approach. The bay model was installed on a representative combat aircraft, incorporating doors and a store. The effect of angle of attack and store position on the aero-acoustic response within the weapon bay was analysed at a transonic Mach number of 0.90. It was found that both numerical approaches are capable of predicting, with good accuracy, the weapon bay’s acoustic spectrum (±10 dB) and store forces and moments (±10%),as compared to experimental data.AIAA Aviation Forum and Ascend 202
Investigation on the mechanism of improving the forming quality of cavitation water jet micro-punching by using a rubber membrane
Get PDFCavitation water jet micro-punching (CWJP) is a high-strain-rate micro-punching technique that utilizes high-energy shock waves generated by the collapse of cavitation bubbles to perform micro-punching on metal foils. However, defects such as brittle fracture, warpage deformation, and edge tearing often occur in the micro-punched holes due to the reverse impact of high-speed backflow. To solve this issue, a novel rubber membrane-assisted cavitation water jet micro-punching (RA-CWJP) technique was proposed in the present work, in which a flexible rubber membrane was introduced as a soft punch to prevent cavitation water jet from entering the die hole. Comparative experiments of the CWJP and RA-CWJP processes were conducted on 50 μm-thick T2 copper foils. The forming quality of micro-punched holes in both processes was evaluated based on microscopic morphology (fracture surface and cross section), shape, and dimensional accuracy. Additionally, the effect of high-speed backflow on the CWJP process was analyzed in detail. Fluid–solid coupling numerical simulations were conducted to better understand the improvement mechanism of the rubber membrane on the forming quality of micro-punched holes. The research results show that applying a 200 μm-thick rubber membrane to the CWJP process prevents brittle fractures, warpage, and edge tearing caused by the reverse impact force of backflow. Meanwhile, the rubber membrane also increases the depth of the shearing zone, and reduces both the rollover zone and burr formation. Compared to the CWJP process, the shape and dimensional accuracy of micro-punched holes formed by the RA-CWJP process increased by 16.1%–63.5% and 45.4%–82.2%, respectively. In the RA-CWJP process, the excellent fluidity and compressibility of the rubber membrane enable precise shearing separation of the copper foil along the die edge. Furthermore, the rubber membrane reduces elastic recovery after punching through enhanced plastic deformation, significantly improving the dimensional accuracy.The authors are grateful for the financial support from the Six Talent Peak Selection and Training Program of Jiangsu [XNYQC-002], the Natural Science Foundations of Jiangsu Province [BK20170752].Archives of Civil and Mechanical Engineerin
Precision laser manufacturing and metrology of nature-inspired bioactive surfaces for antibacterial medical implants
Get PDFFemtosecond laser ablation presents a highly promising method to create bioactive nano/micro-structured metallic surfaces, offering numerous avenues for fabricating diverse types of surface structures. However, the relationship between surface properties and biological functionality, leading to the observed bioactivity remains unclear. This study aimed to investigate the relationship between structured/patterned steel surfaces and bioactivity, identifying key factors that enhance their performance. As opposed to the commonly used controversial parameter, arithmetic surface roughness (Ra), fractal dimension analysis was discovered to be strongly representative in quantifiably evaluating the adhesion of Staphylococcus aureus NCTC 7791 and MG-63 osteoblast-like cells. Surface chemistry and surface energy of structured surfaces showed no significant influence on bacterial adhesion. A specific type of laser-induced periodic structured surfaces with sub-micron wavelengths, high fractal dimension, and high texture aspect ratio demonstrated a 63 % reduction in bacterial adhesion compared to flat surfaces while avoiding cytotoxicity to MG-63 cells. Our findings underline the importance of scale-dependent analysis and the use of fractal analysis in evaluating the effectiveness of laser-structured surfaces for orthopaedic implant applications.All authors acknowledge the financial support provided by the UKRI via Grant No EP/T024607/1. We are particularly grateful to LASEA ltd. for assisting us with sample fabrication using their facilities based in Belgium, Cambridge Royce facilities grant EP/P024947/1 and Sir Henry Royce Institute - recurrent grant EP/R00661X/1.Surfaces and Interface
Mapping research frontiers in gender and sustainability in agricultural development: a bibliometric review
Get PDFGender and sustainability are crucial in agriculture, which remains a significant source of global employment. However, urbanization, industrialization, and technological advancements have reshaped the sector, impacting labor dynamics and gender roles. Traditional agricultural labor faces challenges due to low wages, physically demanding tasks, and unfavorable working conditions. Addressing gender disparities and promoting inclusive work environments is essential for achieving sustainability. According to the ILO (International Labour Office) decent work encompasses productivity and equal employment opportunities for both genders. This study aims to review the literature on gender, sustainability and agricultural development using a bibliometric analysis of Scopus-indexed articles. The findings identify five main research domains: gender dynamics and roles, agriculture and climate change, sustainability and development, human and labor dynamics, and environmental and technological aspects. Additionally, four key scientific communities led the research: Gender studies, agricultural economics, environmental management, and rural sociology. Emerging research trends focus on gender roles in sustainable farming, environmental innovation, and labor governance in agriculture. Spain, the United Kingdom, United States, and Canada lead in knowledge production, contributing significantly to these research domains. This review highlights the importance of interdisciplinary approaches to address the complex issues of gender and sustainability in agriculture. It also specifies a target for expectations research, highlighting that the ILO’s definition of appropriate employment can guide efforts to improve gender equity and labor conditions, ultimately supporting sustainable development in the agricultural sector.Discover Sustainabilit
Wildfire occurrence and damage dataset for Chile (1985–2024): a real data resource for early detection and prevention systems
Get PDFWildfires represent an increasing global concern, threatening ecosystems, human settlements, and economies. Chile, characterized by diverse climatic zones and extensive forested areas, has been particularly vulnerable to wildfire events over recent decades. In this context, real, long-term data are essential to understand wildfire dynamics and to design effective early warning and prevention systems. This paper introduces a unique dataset containing detailed wildfire occurrence and damage information across Chilean municipalities from 1985 to 2024. Derived from official records by the National Forestry Corporation of Chile CONAF, this dataset encompasses key variables such as the number of fires, total burned area, estimated material damages, and the number of affected individuals. It provides an invaluable resource for researchers and policymakers aiming to improve fire risk assessments, model fire behavior, and develop AI-driven early detection systems. The temporal span of nearly four decades offers opportunities for longitudinal analyses, the study of climate change impacts on fire regimes, and the evaluation of historical prevention strategies. Furthermore, by presenting a complete spatial coverage at the municipal level, it allows fine-grained assessments of regional vulnerabilities and resilience.Dat