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A machine learning approach for country-level deployment of greenhouse gas removal technologies
Get PDFThe suitability of countries to deploy five greenhouse gas removal technologies was investigated using hierarchical clustering machine learning. These technologies include forestation, enhanced weathering, direct air carbon capture and storage, bioenergy with carbon capture and storage and biochar. The use of this unsupervised machine learning model greatly minimises the likelihood of human bias in the assessment of GGR technology deployment potentials and instead takes a more holistic view based on the applied data. The modelling utilised inputs of bio-geophysical and techno-economic factors of 182 countries, with the model outputs highlighting the potential performance of these GGR methods. Countries such as USA, Canada, Brazil, China, Russia, Australia as well as those within the EU and Sub-Saharan Africa were identified as key areas suitable to deploy these GGR technologies. The level of certainty of the obtained deployment suitability categorisation ranged from 65 to 98 %. While the results show the need for regional collaboration between nations, they also highlight the necessity for nations to prioritise and integrate GGR technologies in their revised nationally determined contributions.International Journal of Greenhouse Gas Contro
A comparative analysis of acoustic emission sensor embedding in glass fibre composite
Get PDFThe manufacturing process of composite structures permits fully embedding acoustic emission (AE) sensors. While the embedding process may pose challenges, its advantages, if proven, can outweigh the challenges. The increased sensitivity resulting from embedding acoustic emission sensors in composites is still not definitively established. A test was set up with pre-determined AE initiation locations (surface and sub-surface) and pre-determined receiving sensor's location (surface and sub-surface) to ensure any sensitivity increase was evident. The receiving sensor's attenuation along (at 90°) and across the fibres (at 45°) was assessed using two test methods: pencil lead breaking (PLB) and actuator methods. The actuator method involved using two pulse generators, the TGP110 pulse generator and the Mistras FieldCal. A range of specific frequencies were utilised, 30, 60, 150 and 300 kHz, using the FieldCal. The results obtained from the test methods were not in agreement with each other. For example, comparing the sensitivity using surface cracks, the PLB method showed decreased sensitivity when embedding the receiving sensor compared to the actuator method, which demonstrated minimal changes in sensitivity. The research aims to clarify the sensitivity increase obtained when embedding an AE sensor while taking into account the crack's position and frequency.Composites Science and Technolog
Characteristics of shock-induced boundary-layer separation on nacelles under windmilling diversion conditions
Get PDFThe boundary layer on the external cowl of an aeroengine nacelle under windmilling diversion conditions is subjected to a notable adverse pressure gradient due to the interaction with a near-normal shock wave. Within the context of computational fluid dynamics (CFD) methods, the correct representation of the characteristics of the boundary layer is a major challenge in capturing the onset of the separation. This is important for the aerodynamic design of the nacelle, as it may assist in the characterization of candidate designs. This work uses experimental data obtained from a quasi-2D rig configuration to provide an assessment of the CFD methods typically used within an industrial context. A range of operating conditions are investigated to assess the sensitivity of the boundary layer to changes in inlet Mach number and mass flow through a notional windmilling engine. Fully turbulent and transitional boundary-layer computations are used to determine the characteristics of the boundary layer and the interaction with the shock on the nacelle cowl. The correlation between the onset of shock-induced boundary-layer separation and the preshock Mach number is assessed, and it was found that the CFD is able to discern the onset of boundary-layer separation.AIAA Journa
Quantitative SARS-CoV-2 exposure assessment for workers in wastewater treatment plants using Monte-Carlo simulation
Get PDFSeveral studies on COVID-19 pandemic have shown that the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) originating from human stool are detected in raw sewage for several days, leading to potential health risks for workers due to the production of bioaerosols and droplets during wastewater treatment process. In this study, data of SARS-CoV-2 concentrations in wastewater were gathered from literatures, and a quantitative microbial risk assessment with Monte Carlo simulation was used to estimate the daily probability of infection risk through exposure to viable infectious viral airborne particles of the workers during four seasons and under six environmental conditions. Inhalation of bioaerosols and direct ingestion of wastewater droplets were selected as exposure pathways. Spearman rank correlation coefficients were used for sensitivity analysis to identify the variables with the greatest influence on the infection risk probability. It was found that the daily probability of infection risk decreased with temperature (T) and relative humidity (RH) increase. The probability of direct droplet ingestion exposure pathway was higher than that of the bioaerosol inhalation pathway. The sensitivity analysis indicated that the most sensitive variable for both exposure pathways was the concentration of SARS-CoV-2 in stool. So, appropriate aeration systems, covering facilities, and effective ventilation are suggested to implement in wastewater treatment plants (WWTPs) to reduce emission concentration. Further to this, the exposure time (t) had a larger variance contribution than T and RH for the bioaerosol inhalation pathway. Implementing measures such as adding more work shifts, mandating personal protective equipment for all workers, and implementing coverage for treatment processes can significantly reduce the risk of infection among workers at WWTPs. These measures are particularly effective during environmental conditions with low temperatures and humidity levels.Water Researc
Pilots' perceived workload and flight performance while interacting with touchscreen inceptor during instrument landings
No full textIn this study, to dig into the further potential application of the touchscreen in flight operation, an integrated touchscreen system as the aircraft control inceptor was innovatively proposed. The touchscreen inceptor is integrated into the middle of the primary flight display allowing pilots to control the aircraft's movement horizontally (roll) and vertically (pitch) with their fingers. Fifty-six participants (23 pilots and 33 non-pilots) joined the Future Systems Simulator trail to perform instrument landings using the touchscreen and sidestick in conditions without and with simulated turbulence in vertical and horizontal channels. The heart rate variability reflecting the perceived workload was measured using the Inner Balance device. The flight data related to the flight path, touchdown location, and landing load were collected and calculated as the performance score. The three-way analysis of variance was applied to compare the perceived workload and flight performance between touchscreen and sidestick controllers in different disturbance conditions among pilots and nonpilots. The data analysis results indicated that in the scenario of landing with the disturbance, participants' heart rate variability was improved while interacting with the touchscreen inceptor compared to the sidestick. The flight performance of nonpilots while performing landing tasks with sidestick was significantly lower than pilots. Nevertheless, no significant difference in flight performance was found between nonpilots and pilots when using the touchscreen inceptor. The empirical study indicated that the touchscreen could provide a more intuitive interaction of a ‘point-where-you-want-to-go' control technique without the additional input device of sidestick to reduce the mental workload and cognitive stress. Furthermore, there is an evident decrease in performance score with the touchscreen inceptor compared to traditional sidestick due to the unfamiliarity of the touchscreen interactive mode in the prolonged aircraft control process. However, it is notable that nonpilots showed an equal level of flight performance with pilots in landing tasks with touchscreen control, revealing a quick-adapt interactive mode of touchscreen inceptor for novices to perform flight operations. Therefore, the training duration can be remarkably shortened for next-generation pilots, and the cost-efficiency can be improved as well.IEEE/AIAA 42nd Digital Avionics Systems Conference (DASC) 202
Blockchain technology for enhancing sustainable food systems: a consumer perspective
Get PDFThis paper explores the potential of blockchain technology (BCT) in promoting sustainable food production and consumption (SFPC) from a consumer perspective. India, a significant global food producer, faces challenges related to affordability and food logistics due to transport and labour constraints. Food safety concerns, that is, foodborne illnesses and quality issues, alongside unexpected events like COVID-19 and geopolitical conflicts, threaten SFPC. In recent times, consumer focus has shifted a lot towards food safety and security. The study adopted exploratory factor analysis (EFA) to identify the factors strengthening consumer trust through BCT. The EFA helped classify the items into five factors, that is, reliability, sustainability, impact on health, trust and switching intentions. The results reveal that these factors are the most significant reasons consumers are willing to accept a blockchain-enabled food system over a traditional system. The study findings will benefit organisations willing to introduce blockchain within their operations to improve the consumer base. It will also prove to be helpful for researchers and academicians to understand consumer perspectives towards BCT for SFPC.International Journal of Food Science & Technolog
Using not-for-profit innovation networks to transition new technologies across the Valley of Death
Get PDFPurpose
This paper aims to seek answers to the question: What are the relevant factors that allow not-for-profit innovation networks to successfully transition new technologies from proof-of-concept to commercialisation?
Design/methodology/approach
This question is examined using the knowledge-based view and network orchestration theory. Data are collected from 35 interviews with managers and engineers working within seven centres that comprise the High Value Manufacturing Catapult (HVMC). These centres constitute a not-for-profit innovation network where suppliers, customers and competitors collaborate to help transition new technologies across the “Valley of Death” (the gap between establishing a proof of concept and commercialisation).
Findings
Network orchestration theory suggests that a hub firm facilitates the exchange of knowledge amongst network members (knowledge mobility), to enable these members to profit from innovation (innovation appropriability). The hub firm ensures positive network growth, and also allows for the entry and exit of network members (network stability). This study of not-for-profit innovation networks suggests the role of a network orchestrator is to help ensure that intellectual property becomes a public resource that enhances the productivity of the domestic economy. The authors observed how network stability was achieved by the HVMC's seven centres employing a loosely-coupled hybrid network configuration. This configuration however ensured that new technology development teams, comprised of suppliers, customers and competitors, remained tightly-coupled to enable co-development of innovative technologies. Matching internal technical and sectoral expertise with complementary experience from network members allowed knowledge to flow across organisational boundaries and throughout the network. Matrix organisational structures and distributed decision-making authority created opportunities for knowledge integration to occur. Actively moving individuals and teams between centres also helped to diffuse knowledge to network members, while regular meetings between senior management ensured network coordination and removed resource redundancies.
Originality/value
The study contributes to knowledge-based theory by moving beyond existing understanding of knowledge integration in firms, and identified how knowledge is exchanged and aggregated within not-for-profit innovation networks. The findings contribute to network orchestration theory by challenging the notion that network orchestrators should enact and enforce appropriability regimes (patents, licences, copyrights) to allow members to profit from innovations. Instead, the authors find that not-for-profit innovation networks can overcome the frictions that appropriability regimes often create when exchanging knowledge during new technology development. This is achieved by pre-defining the terms of network membership/partnership and setting out clear pathways for innovation scaling, which embodies newly generated intellectual property as a public resource. The findings inform a framework that is useful for policy makers, academics and managers interested in using not-for-profit networks to transition new technologies across the Valley of Death
State dependent regional pole assignment controller design for a 3-DOF helicopter model
Get PDFFor linear systems, a state feedback control law can be easily designed to keep all closed-loop poles inside a specified disk since the locations of the poles are unique. However, its application to nonlinear systems is not so simple. Therefore, this paper introduces a new pole placement method, named as State Dependent Regional Pole Assignment, for nonlinear systems. This proposed method produces a state dependent feedback control law, enabling the eigenvalues of the closed-loop matrix to be placed in a specified disk to achieve the desired control performance characteristics. The effectiveness of the method is tested on the 3 DOF Helicopter experimental setup. To verify its effectiveness, the experimental results of the nonlinear method are compared with those of the linear method.2023 International Conference on Unmanned Aircraft Systems (ICUAS
Radar detection performance via frequency agility using measured UAVs RCS data
Get PDFThis paper addresses radar detection performance prediction (via measured data) for drone targets using a frequency agility-based incoherent (square-law) detector. To this end, a preliminary statistical analysis of the integrated Radar Cross Section (RCS) resulting from frequency agile pulses is carried out for drones of different sizes and characteristics, using data acquired in a semi-controlled environment for distinct frequencies, angles, and polarizations. The analysis involves fitting the integrated RCS measurements with commonly used one-parametric and two-parametric probability distributions and leverages the Cramér-von Mises distance and the Kolmogorov Smirnov test. Results show that the Gamma distribution appears to accurately model the resulting fluctuations. Hence, the impact of integration and frequency agility on the RCS fluctuation dispersion is studied. Finally, detection performance of the incoherent square-law detector is assessed for different target and radar parameters, using both measured and simulated data drawn from a Gamma distribution whose parameters follow the preliminary RCS statistical analysis. The results highlight a good agreement between simulated and measurement-based curves.IEEE Sensors Journa
Simulation of a floating solar farm in waves with a novel sun-tracking system
Get PDF12th International Workshop on Ship and Marine Hydrodynamics (IWSH-2023) 28/08/2023 - 01/09/2023 Aalto University, Espoo, FinlandThe awareness of the energy and climate crisis has accelerated the development of renewable energy sources. Photovoltaic (PV) solar power plants harvest clean solar energy and convert it to electricity, which will be one of the most promising alternatives to the power industry in the context of a low-carbon society. Due to its low power density, the traditional deployment of PV systems on land or inland rivers requires much space. Therefore, industries are increasingly interested in expanding offshore Floating PhotoVoltaics (FPV) to oceans, where FPV has less influence on the marine environment and does not occupy precious space for land resources and human activities. This study performs a hydrodynamics-based structural response analysis for a novel FPV system in OpenFOAM. The wave-proof FPV platform is newly designed for this work, which integrated breakwater technologies to sustain the system's survivability in harsh ocean-wave environments. Firstly, the rational mooring types for FPVs installed close to the island are studied considering seabed effects. Subsequently, extensive parametric studies have been conducted to determine a rational design strategy for the mitigation of wave impact. Several potential effects of the proposed platforms on the hydrodynamics in a coastal sea are evaluated for the first time.Innovate UK: 10048187IOP Conference Series: Materials Science and Engineerin