Object detection and classification with limited training data

Since the rise of deep learning around a decade ago, the field of object detection and classification using a convolutional neural network (CNN) and its variants has grown exponentially...Applied Science

Morphological changes of lenticels and their role in gas exchange and sprouting physiology of potato tubers during postharvest storage

The application of exogenous gases has been used to suppress sprouting in stored potato tubers. However, their efficacy in extending ecodormancy largely depends on achieving optimal gas exchange between the storage atmosphere and the tuber itself. This study aimed to investigate morphological variations and spatial distribution of lenticels and apical buds and to identify their potential role in tuber respiration rate and sprouting of five potato cultivars (‘Hermes’, ‘Lady Claire’, ‘Lady Rosetta’, ‘Saturna’, and ‘VR808’) during storage. Results revealed a consistent spatial pattern wherein the apical section of potato tubers exhibited significantly higher bud counts compared to lateral and stolon regions. ‘Lady Claire’ stood out as having the highest number of apical buds among the cultivars studied. Digital image analysis showed a seven times higher number of buds surrounding the apical eye and these were generally smaller than those distributed across the skin. ‘Saturna’ displayed double the lenticel density (12 lenticels cm-2) in smaller tubers, suggesting an inverse relationship between tuber size and lenticel density. ‘Lady Claire’ and ‘Saturna’ had respiration rates of 2.75 and 1.9 mL CO2 kg-1 h-1, respectively, and were selected for additional respiration and ethylene efflux analyses. In both cultivars, distinct spatial differences were observed, with the apical section exhibiting a seven-fold increase in lenticel density compared to the lateral and stolon sections. Respiration rate increased five-fold when apical lenticels were blocked, whereas it decreased 30-fold when the apical was the only unblocked section, suggesting differential physiological activity across lenticel locations. The apical sections, with the highest lenticel density, exhibited elevated respiration rates as a stress-induced physiological response upon blockage, compared to the lateral and stolon sections. Lenticels changed their morphology during storage, erupting before bud movement, suggesting lenticel eruption could be used as a pre-symptomatic visual marker of dormancy break. This study highlights the critical role that lenticel morphology and spatial distribution may have in determining potato tuber gas exchange and refining allied storage regimes.This study was supported by PepsiCo International Ltd. We thank the Biotechnology and Biological Sciences Research Council (BB/M027295/1) for partially sponsoring the research work.Frontiers in Plant Scienc

Intelligent manufacturing paradigms: linking design optimization and sustainability in large-area additive manufacturing

The next generation of computer-aided intelligent manufacturing systems must enable the exploration and exploitation of cause-and-effect relationships across multiple disciplines. This capability strengthens human decision-making and supports sustainability-by-design in digital design-to-manufacturing workflows. To enhance system intelligence, seamless integration is needed between material systems, design methods, manufacturing processes, and sustainability metrics. This study presents a case study on large-scale mold manufacturing using large area additive manufacturing. A multidisciplinary design optimization (MDO) framework combines parametric and generative design strategies with manufacturing process planning, material selection, and environmental impact analysis. The study examines the trade-offs between structural integrity, production efficiency, and ecological impact, focusing on two different short fiber-reinforced polymer materials. Empirical and model-driven analyses methods reveal a direct correlation between mass reduction and improved sustainability. While carbon fiber reinforcement offers better structural performance, it also increases the carbon and water footprints by approximately 400% and 100%, respectively, compared to glass fiber alternatives. The case study on wind turbine rotor blade mold manufacturing highlights how parametric and generative design approaches can produce both structurally sound and sustainable solutions. Future research should focus on improving the algorithmic transparency of commercial software, increased flexibility to add manufacturability constraints, and potentially including sustainability models to enhance the intelligence in design-to-manufacturing workflows. This study highlights the potential of intelligent manufacturing systems to drive cleaner, more efficient, and sustainable production processes.This work was supported by the project D2M (346874) Research Council of Finland - Academy Research Fellow.The International Journal of Advanced Manufacturing Technolog

Comparison of laboratory-scale methods for assessing deposit-induced corrosion of boiler materials in biomass combustion and recovery boilers

Various instrumental methods for analyzing high-temperature corrosion of boiler materials were explored and compared. These methods were applied to gain deeper insights into corrosion due to two salt mixtures containing Na, K, SO4, and Cl below and above the mixtures’ first melting points. Stainless steel AISI316 and high-alloyed Sanicro28, typically used in heat exchangers in power plants, were exposed to salt mixtures in a laboratory tube furnace for 168 h. The extent of the metal corrosion following exposure was measured through mass loss, changes in the surface topography using optical 3D imaging, and dimensional metrology. Additionally, the morphology, thickness, and composition of the formed oxide scales were characterized using SEM–EDX. The information gathered from each method confirmed the impact of the synthetic salt deposit and temperature on the metal corrosion. Combining several methods enables detailed studies of changes taking place on the metal surface after exposure to challenging environments. The results also suggested that partial melting of the deposit had a higher impact on the corrosion than its chloride content.This work was conducted within the Academy of Finland project “Initiation and propagation of high-temperature corrosion reactions in complex oxygen-containing environments” (Decision no. 348963).The research was also part of the activities of the project Clean and efficient utilization of demanding fuels (CLUE2023-2025) supported by the industrial partners: ANDRITZ Oy, Valmet Technologies Oy, UPM-Kymmene Oyj, Metsä Fibre Oy, and International Paper Inc.High Temperature Corrosion of Material

Occurrence of mycotoxins, diversity of aspergillus section flavi, along the cassava value chain, and innovative strategy for aflatoxin reduction during storage in Uganda

Cervini, Carla - Associate SupervisorThis thesis (1) Investigated the cassava handling practices along the value chain in two contrasting cassava production and consumption regions (each with four districts) of Uganda, to identify critical points that may potentially contribute to mycotoxin contamination, understand the knowledge extent about mycotoxins, and identify and collect the major consumed cassava products, (2) determined the occurrence and distribution of mycotoxins in major cassava products to identify the levels of mycotoxin contamination along the major value chain actors (farmer and wholesaler and processors) from samples in different regions, (3) assessed the fungal diversity, and identity of dominant fungal species (Aspergillus section Flavi ) isolated from soil and cassava products from Uganda, and (4) developed an innovative strategy with potential to completely eliminate occurrence of aflatoxins during storage. One of the major outputs of this thesis was to develop a Hazard Analysis and Critical Control Point plan for the cassava value chain in Uganda. Key practices identified as likely to predispose cassava to mycotoxins contaminations include peeling cassava on bare ground, direct ground drying, inadequate storage conditions, and poor processing techniques. Data from 210 individual interviews, 34 key informants and 4 focus group discussions revealed that majority (51 %) of farmers peeled cassava directly on bare ground, resulting in direct contact with soil that potentially harbours mycotoxin-producing fungi, such as Aspergillus section Flavi. During post-harvest handling, 51.6 % of farmers dried cassava chips directly on bare ground. Nearly, all (95.2 %) of wholesalers packed cassava chips in local gunny bags and placed them on ground instead of pallets. In the processing of cassava chips into flour, only one of the 14 processing machine was certified by the Uganda National Bureau of Standards. The greatest proportion (73 %) blended cassava flour with flour from mycotoxin-susceptible crops mainly maize, millet, and sorghum. Most (96.2%) of the people along the cassava value chain did not understand what the term mycotoxins meant, but 56% were familiar with the term aflatoxins. Of the cassava value chain actors aware of mycotoxins, 82.9 % knew of methods for reducing aflatoxin contamination, but only 40.9 % were putting such methods into practise. Cassava chips and flour were the predominantly consumed cassava products by 95% of respondents and were assessed for mycotoxin contamination. A total of 192 samples of cassava products (96 flour and 96 chips) analysed using LC-MS/MS revealed that all positive samples irrespective of their origin (flour or chips), exhibited aflatoxin B1 (AFB1) levels exceeding the EU regulatory threshold of 5 µg/kg. For the first time, the study reported the highest levels of AFB1 in Uganda’s cassava, ranging from 13.1 to 298 µg/kg in flour and 2.24 to 420 µg/kg in chips. The sum of fumonisins (FB1+FB2), zearalenone (ZEN) and deoxynivalenol (DON) were significantly (P<0.05) higher in cassava flour (14.3 µg/kg; 3.71 µg/kg; 25.1 µg/kg) compared to chips (6.54 µg/kg; 1.25 µg/kg; 0.25 µg/kg), respectively. Cassava flour samples from farmers exhibited significantly (P<0.05) higher mean concentrations of AFB1 (27.1 µg/kg), total aflatoxins (78.2 µg/kg) and ochratoxin A (79.6 µg/kg) in contrast to wholesalers, at 8.91, 5.79 µg/kg and 2.44 µg/kg, respectively. The risk of AFB1 exposure to cassava consumers was also determined and revealed that, cassava consumers in Northern Uganda are at a higher risk of Hepatocellular Carcinoma (HCC)-a type of liver cancer, with an estimated 2.06 cancer cases per 100,000 individuals per year compared to those in Eastern Uganda at 0.25. Given that aflatoxins were the most dominant mycotoxins in Uganda’s cassava products, it was paramount to identify the aflatoxin producing species for targeted intervention. To identify the aflatoxin producing species in Uganda’s cassava, a total of 288 samples (soil-48, tubers-48, chips-96, and flour-96) were assessed for the number of colony forming units (CFU/g) growing on Dicloran-18-glycerol agar (DG-18). The most dominant fungi (Aspergillus section Flavi) were further assessed for its aflatoxigenicity, and a polyphasic approach was followed to identify the species. Aspergillus (84%), Penicillium (2.1%), Fusarium (3.62%), and Rhizopus (9.9%) were frequently observed fungal genera. Within the Aspergillus genus, species belonging to Aspergillus section Flavi were significantly (P=0.021) the most dominant with highest CFU/g of 1.48 ×105. A total of 77/162 (47.5%) was aflatoxigenic. 22/27 isolates from soil were aflatoxigenic, labelling it a strong reservoir for aflatoxigenic species. Following polyphasic approach, 64% (33/52) of the isolates were Aspergillus flavus, 25% (13/52) Aspergillus parasiticus, 8% (4/52) Aspergillus novoparasiticus, one Aspergillus minisclerotigenes, and another Aspergillus tamari. Three distinct Aspergillus isolates were identified, including one identified as Aspergillus tamari, which produced AFB1, AFB2, and AFG1 but not cyclopiazonic acid (CPA). In addition, two Aspergillus parasiticus isolates were found to produce only AFB1, AFB2, and CPA. These species will be sent for confirmation to Westerdijk Institute for further investigation. Thus, to manage aflatoxins in Uganda, there is need to develop innovative solutions specifically targeting Aspergillus section Flavi isolates with strong focus on Aspergillus flavus. In this study we investigated the efficacy of sodium metabisulphite on reducing aflatoxins during storage. Both in vitro laboratory and field experiments were conducted. In vitro involved growing three highly aflatoxin-producing species (A. flavus, A. parasiticus, and A. minisclerotigenes) in cassava-based media at different water activity (0.90, 0.95, 0.99 aw) at different concentrations of sodium metabisulphite (0, 125, 250, 500, 1250, 1500 mg/L) for 15 days. While field experiments were set up in Uganda’s field conditions in districts with different climatic conditions. The initial fungal load, and AFB1 levels were determined. In vitro results showed that NaMBS completely inhibited the growth of A. flavus, A. parasiticus, and A. minisclerotigenes—reducing growth (colony diameters) from 48 mm, 45 mm, and 20 mm, respectively, to zero—at a concentration of 1250 mg/L of sodium metabisulphite. Field experiments were set up in Uganda’s field conditions in districts with varying climatic conditions. The initial fungal load, and AFB1 levels were determined. The results in field conditions revealed that NaMBS had a significant potential in reducing both the fungal load and completely reducing initial AFB1 concentration. Cassava chips placed in traditional bags without NaMBS treatment showed the highest levels of AFB1 levels (146.6 µg/kg) and fungal load of 20.4 mean cfu/g ×10^5 indicating that traditional bags, when untreated with NaMBS, do not significantly reduce AFB1 and fungal load. While PICS bags without NaMBS treatment also exhibited a considerable amount of AFB1 (91 µg/kg) and fungal load of 6.1 mean cfu/g ×10^5. However, the application of NaMBS treatment led to a drastic reduction in AFB1 from 185 µg/kg to 10.9 µg/kg (94.5% reduction rate) and fungal load 3.5 mean cfu/g ×10^5(82.8% fungal reduction) for traditional bags and 0.23 µg/kg (99.9% reduction rate) and fungal load of 1.9 mean cfu/g ×10^5 for PICS bags. These findings suggest that the addition of NaMBS treatment is highly effective in reducing the fungal load and AFB1 in both types of bags. This thesis provides a major contribution towards management of mycotoxins especially aflatoxins within cassava production in Uganda. Finally, based on Hazard Analysis and Critical Control Point (HACCP), out of the six main steps of cassava flour production which include harvesting, peeling, milling, storage, packaging and drying, the critical control points are: storage, packaging, and drying on bare ground. Harvesting, peeling and milling are not critical control points (CCPs) but possess potential areas of contamination that should be prevented. Key ecophysiological factors that should be monitored to manage the CCPs below the control limits include moisture content (ideally below 13%), water activity (aw between >0.6), and relative humidity (preferably below 65%). Also, total aflatoxin levels should be kept below 10 µg/kg. Implementing good handling practices and good agronomic practices are also vital to manage these CCPs.PhD in Environment and Agrifoo

Deep learning-driven x-ray digital tomosynthesis (DT) imaging for aerospace composite inspection

The structural integrity of aerospace-grade Glass Fiber Reinforced Polymer (GFRP) composites is critical, yet conventional non-destructive testing (NDT) methods often struggle to detect subsurface defects reliably due to poor signal-to-noise ratios, low contrast, and complex internal structures. To address these limitations, this study proposes a novel AI-driven framework that integrates low-power X-ray Digital Tomosynthesis (DT) imaging with state-of-the-art deep learning models for defect segmentation in composite materials. Specifically, two state-of-the-art instance segmentation models, YOLOv8 (You Only Look Once, version 8) and Detectron2, are employed to automatically segment flaws in the DT images of the composite specimens. A dedicated dataset of low-power X-ray DT scans of GFRP composite specimens with annotated defects was curated for training and evaluation. The segmentation performance of each model was quantitatively evaluated using metrics such as the Dice similarity coefficient and Intersection-over-Union (IoU), along with inference time measurements. Experimental results demonstrate that YOLOv8 processes images significantly faster (~6.9 ms per image) than Detectron2 (~10.3 ms), enabling near real-time analysis. Conversely, Detectron2 achieves a higher segmentation accuracy (Dice ~86% versus ~74% for YOLOv8), underscoring the trade-off between computational efficiency and segmentation precision. These findings validate the potential of combining low-power DT imaging with deep learning for high-fidelity defect identification, substantially improving the prospects for near real-time composite inspection. Future work will focus on further model optimization (e.g., via quantization and pruning) and the integration of this framework with autonomous robotic inspection systems, thereby extending the capabilities of AI-driven NDT in aerospace applications.Aerospace Technology InstituteThis work was supported by ATI funding for advanced manufacturing inno-vation - ATI ROBOT-MOUNTED 3D X-RAY INSPECTION.Towards Autonomous Robotic Systems 26th Annual Conference, TAROS 202

An exploration of new methods to assess energy availability in the English oak (Quercus robur)

Existing methods of measuring the capability of foods to drive ecosystem processes are reviewed and found to be inadequate; these included bomb calorimetry and plant quality assays. This thesis explores two alternative methods, one in vivo and one in vitro, based on the rate of supply of energy and compares these to plant quality measurements and calorific content. A pilot study was undertaken using cow parsley (Anthriscus sylvestris) to determine sampling regime and establish laboratory techniques for fibre content measurement. The energy availability of different parts of the English oak (Quercus robur) are compared by measuring their decomposition rates in oak woodland soil. In this form the soil is acting as an in vivo microbial digester and the rates at which weight loss occurs in the samples is converted to an energy release rate dimensioned in kW.kg-¹. This unit mass power measurement is compared to heat of combustion data derived from bomb calorimetry which is dimensioned in joules.kg-¹. Variation in unit mass heat of combustion between plant parts is small at 10% compared to the 400% (at 18 days) and 720% (at 115 days) variation in unit mass power output between plant parts as measured in the tests undertaken. Unit mass power output correlated with conventional plant quality assays of the oak. A third set of experiments has begun the development of the laboratory based measurement of energy availability under standard conditions. Each plant material was macerated in a roller mill for thirty minutes (after hammer milling where required) and subjected to a cellulose digest. A biological oxygen demand measurement was made before and after the cellulose digest. These measurements of metabolisable energy were converted to an energy supply rate by establishing a theoretical gut retention time based on the time a standard amount of cellulose takes to digest the cellulose in a unit mass of sample. The results of the in vivo and in vitro measurements were qualitatively similar but with the in vitro test energy was accessed more quickly and therefore had a higher power output rate. It is suggested that ecosystem or community energetics are dependent on energy availability rather than total energy content and that the importance of this distinction will vary between biomes.International Ecotechnology Research CentrePhD in International Ecotechnology Research Centr

Introduction of social benefits to the tera – gas turbines and pipelines

Igie, Uyioghosa - Associate SupervisorThe aim of this work is the techno-economic and environmental risk analysis (TERA) of the Trans-Saharan Gas Pipeline on gas turbine compressor stations. A pipeline project encompasses many aspects, viz., choice of compressor station location, power of each compressor station, compressor station availability, pipeline sizing, and it includes socioeconomic impacts. Therefore, this research considered the impacts of engine availability, compressor station location, and socioeconomic impact in the TERA for pipelines while optimising for the lowest lifecycle cost. The pipeline and gas compressor modules were evaluated considering segmented pipe length, elevation, and station location ambient temperature variation at varying flow conditions. The design and off-design points performance of the selected gas turbine models were simulated using Turbomatch to obtain essential performance data required for the techno socio- economic analysis. The unit availability was evaluated based on a developed local maintenance schedule and failure rate retrieved from literature studies. The analysis considered the social impacts and benefits of compressor station locations. A scenario-based techno socio-economic analysis was performed to show the sensitivities of the compressor station and pipeline systems to social and technical aspects of the project in terms of social benefits and availabilities. The economic model was developed based on social benefit algorithms and the variation in compressor station location ambient temperatures at varying flow conditions. Results show compressor station system availabilities of 0.2542, 0.4657, and 0.9926 with corresponding lifecycle costs of $22.22 billion,$23.05 billion, and $24.11 billion assuming a 15% discount rate for scenarios 1, 2, and 3, respectively. An increase in availability leads to a corresponding increase in the lifecycle cost estimate. The employment and road benefit ratios would increase by a factor of 10 and reciprocal of new locations. This ratio is for every 10 km decrease in the distance at each station location. Results show the significance of the modelling and optimisation approaches utilised in this research for compressor station locations optimisation of the integrated pipeline TERA. This will guide decision-makers on the ultimate selection of engine configurations that will give the optimum lifecycle cost and socio-economic benefits at the optimised station locations.Petroleum Technology Development Fund (PTDF)PhD in Aerospac

Invaders and containers: cognitive representations of biological and particular matter (bioPM)

Air quality management concerns the assessment, analysis and mitigation strategies associated with ensuring that air is breathable and non-toxic. Successful management is a cognitively intensive task, knowledge-focused and converges multiple sources of information to develop a shared understanding of a problem. To operate effectively in this space, managers and operational teams share common points of reference in discussing problems and solutions, strategies, tactical briefings, etc., and communication and technical language use are key to the discipline. However, few studies have homed in on the language communities of air quality management discourse, and fewer still have exploited this to gain insight into the cognitive processes underpinning salient operational knowledge production. This paper draws upon a discussion from a multi-stakeholder workshop on bioaerosols and the built environment and draws upon Cognitive Linguistics to systematically examine the cognitive structuring of those different stakeholder representations. This approach is then explored as a contribution to good practice in air quality knowledge management and communication that is consistent with studies on cognitive and learning science and has potential for policy formulation.Natural Environment Research Council (NERC)This research was funded by the Natural Environment Research Council (NERC), grant number NE/V002171/1.Pollutant

Patent strength, innovation, and CO2 emissions: evidence of non‐linear environmental impacts across economies

This study investigates the complex relationship among patent strength, innovation, and CO2 emissions by exploring a pathway through which the strength of patents influences environmental sustainability. Utilizing structural equation modeling (SEM), we examine data from a diverse set of OECD and non‐OECD countries over the period 1998–2017. Our results reveal a non‐linear, S‐shaped relationship between patent stringency and CO2 emissions, highlighting that while stronger patent protections can initially lead to increased emissions due to industrial activity, they may also encourage efficiency improvements and cleaner practices after reaching a certain threshold. However, excessively stringent patents may revive emissions by reducing competition and innovation. The findings emphasize the need for nuanced patent policies that consider both economic growth and environmental sustainability.Business Strategy & Developmen