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Life cycle analysis of ammonia-driven calcium looping processes for post-combustion CO2 capture in NGCC power plants
Get PDFIntegrating calcium looping (CaL) based carbon capture and storage (CCS) technology with an existing natural gas combined cycle (NGCC) power plants offers a promising solution for low-carbon energy production. This work introduces a novel NH3-driven CaL process for retrofitting NGCC plants. The economic performance and environmental impacts of the process were analyzed through life cycle analysis and compared with those of conventional oxy-fuel CaL and solar-driven CaL technologies. Results indicate that, the NH3-driven CaL demonstrates with a very low energy penalty of only 2.6 points, while the solar-driven CaL method faces a 14-points energy penalty. From an environmental perspective, the NH3-driven CaL method, with considering various ammonia sources, significantly impacts the environment more than oxy-fuel and solar-driven methods, with global warming potential values of 207.7 (oxy-fuel), 170.7 (solar), and 197.6–258.8 g CO2-eq/kWh (green NH3). Economically, based on an annual operation time of 4000 h of NGCC, the solar-driven CaL system has the lowest Life Cycle Cost of GHG Removed (LCOR) at 247.7 /t in 2050, the NH3-driven CaL system is expected to gain a significant advantage in economic at 46.5 /Nm3. And it is important to pay attention the clean production process of ammonia to reduce its impact on the environment.This work was supported by China Postdoctoral Science Foundation (No. 2024M752134 and No. 2024T170587) , Shenzhen Science and Technology Program (No. KCXFZ20240903093459001 and No. ZDSYS20230626091400001), National Key Research and Development Program of China (No. 2023YFB4006005)and Natural Science Foundation of Guangdong Province (No. 2024A1515012661).Journal of Environmental Managemen
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Age and career resilience through the lens of life course theory: examining individual mechanisms and macro‐level context across 28 countries
Get PDFCareer resilience is critical to the world's aging workforce, aiding older workers in adapting to the ever‐evolving nature of work. While ageist stereotypes often depict older workers as less resilient when faced with workplace changes, existing research studies offer conflicting evidence on whether older age hinders or improves career resilience. In response to this conflicting evidence, the present study employs multi‐level data from 6772 employees in 28 countries to examine the age‐career resilience relationships and underlying mechanisms, hence advancing our understanding of career resilience across the life course. By integrating macro‐contextual factors such as the unemployment rate and the culture of education with individual‐level mechanisms such as positive career meaning and career optimism, we provide a comprehensive model explaining how career resilience varies across age groups. Grounded in life course theory, our findings resolve prior inconsistencies in resilience research, contribute to bridging the micro‐macro gap in HRM literature, and challenge existing age‐based stereotypes.Human Resource Management Journa
Investigation of procurement risk management strategies in the post-contract award phase.
No full textYates, Nicky - Associate SupervisorThis research empirically investigated how procurement risk management (PRM) strategies are used to manage risks in the post-contract award phase. Through three sequential papers, this study adopted multiple methods to gain insights into the procurement risks, risk management strategies, and risk management tools and techniques used in the post-contract award phase in manufacturing sector.
Paper 1 is a literature review of the risk management strategies used in the three procurement phases: pre-contract, selection and contracting, and post-contract award. The author conducted an SLR of 100 peer-reviewed articles published between 2000 and 2025. The key findings of this study are twofold. First, it synthesized four main themes: procurement risks, procurement risk management tools and techniques, procurement risk mitigation strategies, and factors that influence the selection of risk mitigation strategies across the three procurement phases. Second, the findings highlighted that procurement risk management tools and techniques in the post-contract award phase have been neglected in the literature compared to the pre-contract, and selection and contracting phases.
Paper 2, an empirical study, adopted a qualitative approach to gain insights into procurement risk management in the post-contract award phase. The author interviewed Procurement professionals (23) from 7 manufacturing industries in the United Kingdom (UK) and highlighted three key findings based on the interview insights. First, the results identified five risk categories: supplier performance, contract design, supplier relationship, ethical, and disruption risks. Second, procurement professionals combined technological tools, such as data analytics and machine learning, with human engagement techniques, including site visits and review meetings, to identify and assess risks and plan mitigation strategies. Third, a combination of preventive and reactive PRM strategies were implemented in the post-contract award phase.
Paper 3, an empirical study, examined how sociological mechanisms affect procurement risks and procurement risk management performance during the post-contract award phase. A quantitative survey was conducted among 313
procurement professionals from the US automotive manufacturing industry. This study has four key findings. First, combining trust with information sharing, commitment, and flexibility mitigates the negative effects of switching costs on procurement risk management performance than using trust alone. Second, combining trust with information sharing, commitment, and flexibility mitigates the negative effects of switching costs and negotiation costs on procurement risk management performance than using trust alone. Third, sociological constructs are insufficient as PRM mechanisms to mitigate the negative impact of environmental uncertainties on procurement risk management performance. Fourth, sociological constructs are insufficient as PRM mechanisms to mitigate the negative influence of supplier opportunistic behaviours on procurement risk management performance.
Overall, this thesis makes several key contributions and extends the literature in the following ways. This SLR study contributes to the existing literature by aligning the fragmented strands of risk management literature and systematically synthesizing the procurement risks, the tools and techniques for identifying, assessing, and mitigating risks, and the risk mitigation strategies in each procurement phase. Second, it provides a new, empirically based procurement risk management model that integrates procurement risk identification, assessment, and mitigation strategies into the post-contract award phase. Third, it provides new empirical evidence that combining trust with information sharing, commitment, and flexibility mitigates the negative effects of switching costs and negotiation costs on procurement risk management performance more effectively than using trust alone. Fourth, it provides new empirical evidence that combining trust with information sharing, commitment, and flexibility mitigates the negative effects of switching costs and negotiation costs on procurement risk management performance than using trust alone.PhD in Leadership and Managemen
Redesigned crinkle washer for piezoelectric energy generation
No full textStructures are used for piezoelectric energy harvesters as a way of redirecting the path of an inputted force so that the piezoelectric element can better convert the mechanical energy to electrical energy. A popular structure used for energy harvesting in compressive force scenarios are the cymbal structure or disc spring due to larger spring rates and the ability to turn compression into radial expansion and thus create surface radial tensile stress on the face plane of a piezoelectric element which has been identified as a beneficial characteristic. The drawbacks of the cymbal washer are found when multiplying the washer in a stack configuration, as the shape of the cymbal is only able to activate a single face and the shape creates increased open space which affects power density of an energy harvesting system. This research is further investigating the wave (crinkle) washer and understanding the benefits of a washer that has a rotational symmetry which a single washer can be used to radially stress two piezoelectric elements simultaneously during compressive loading. Simulations show the iterations of the currently available crinkle washer, adjusting design parameters such as curvatures and waves to create an optimised structure resembling a hyperbolic paraboloid washer. The double piezo compression set up was then simulated to receive an area force of 1000 N/m2 vertically onto the top steel backing plate with a diameter of 22 mm and an area of 380 mm2 to demonstrate a total compressive load of 0.38 N, and resulted significant performance improvements. The final optimised circular disc washer charged two 10 nF capacitors to 1.13 mV and 0.89 mV, compared to just 0.01 mV and 0.009 mV achieved with the standard crinkle washer, the performance boost was achieved by removing internal stresses found to be localised to the internal diameter wave radii. The optimised novel crinkle hyperbolic paraboloid configuration was further optimised with slits to eliminate inner stress regions between wave peaks, vastly improving both power density and overall energy harvesting performance with final capacitor voltages of 16.03 mV and 19.77 mV.Engineering and Physical Sciences Research CouncilThis work was supported by Engineering and Physical Science Research Council (EPSRC) funded ICASE projectFrontiers in Mechanical Engineerin
Data relating to Sachet Scoping Review
No full textSingle-portion multi-layer sachets are a popular packaging format for food, home and self-care products in low-income countries. Sachet waste is non-recyclable, and visibly litters land, freshwater and ocean environments, particularly in Southeast Asian countries described as having a ‘sachet economy’. As annual sales approach 1 trillion, we ask whether low levels of research on sachets and the sachet economy could contribute to misinformation about environmental and socioeconomic damage and a lack of policy action to reduce sachet use. Based on the PRISMA-ScR method, our scoping review included novel comparative analyses of multiple exclusion screenings and a bespoke waste hierarchy for literature analysis to reveal how information available to stakeholders changes as criteria are tightened. We found little empirical research, with knowledge gaps often addressed by Institutions and NGOs, particularly regarding alternatives to the sachet economy at the top of the waste hierarchy. Policymakers and consumers in the Philippines and Indonesia were the most common target audience and geographical context. A high proportion of grey literature and inconsistent terminology may introduce the potential for bias and reduced impact.
Our research highlights the urgency of further research into social and environmental impacts of the sachet lifecycle and alternatives such as refill.Engineering and Physical Sciences Research Council (EPSRC
Structural fault detection and diagnosis for combine harvesters: a critical review
Get PDFCombine harvesters, as essential equipment in agricultural engineering, frequently experience structural faults due to their complex structure and harsh working conditions, which severely affect their reliability and operational efficiency, leading to significant downtime and reduced agricultural productivity during critical harvesting periods. Therefore, developing accurate and timely Fault Detection and Diagnosis (FDD) techniques is crucial for ensuring food security. This paper provides a systematic and critical review and analysis of the latest advancements in research on data-driven FDD methods for structural faults in combine harvesters. First, it outlines the typical structural sections of combine harvesters and their common structural fault types. Subsequently, it details the core steps of data-driven methods, including the acquisition of operational data from various sensors (e.g., vibration, acoustic, strain), signal preprocessing methods, signal processing and feature extraction techniques covering time-domain, frequency-domain, time–frequency domain combination, and modal analysis among others, and the use of machine learning and artificial intelligence models for fault pattern learning and diagnosis. Furthermore, it explores the required system and technical support for implementing such data-driven FDD methods, such as the applications of on-board diagnostic units, remote monitoring platforms, and simulation modeling. It provides an in-depth analysis of the key challenges currently encountered in this field, including difficulties in data acquisition, signal complexity, and insufficient model robustness, and consequently proposes future research directions, aiming to provide insights for the development of intelligent maintenance and efficient and reliable operation of combine harvesters and other complex agricultural machinery.This research work was supported by the Taizhou Science and Technology Support Programme (Agriculture) Project: Key Technology and Equipment for Efficient Harvesting of Pea Seedlings Growing in Disorder in the Field (TN202315); the Postgraduate Research & Practice Innovation Program of Jiangsu Province (KYCX25_4246); the Postgraduate Research & Practice Innovation Program of Jiangsu Province (SJCX25_2455); and the Key Laboratory of Modern Agricultural Equipment and Technology of Ministry of Education, Jiangsu University (MAET202326)Sensor
Turboelectric distributed propulsion system design and tank sizing for novel hydrogen-fuelled aircraft: a mission-level analysis
Get PDFIn an ever-growing civil aviation industry, the need to reduce the related
carbon footprint is more relevant than ever. One way to substantially contribute
to this cause is to use liquid hydrogen (LH₂) as a fuel, which would allow for
zero in-flight CO₂ emissions. However, there are major challenges associated
with its implementation, both from the perspective of the airframe design as well
as the propulsion and fuel system architecture.
This research contributes to knowledge by addressing the sizing of the LH₂
aircraft components from a mission level perspective. More specifically two
novel aspects are addressed based on that philosophy: LH2 tank sizing with
gaseous hydrogen (GH₂) extraction for pressure control and design space
exploration of turboelectric distributed propulsion (TeDP) and partially TeDP
configurations powered by LH₂.
This is achieved through a developed framework that enables the
assessment of a hydrogen aircraft and its subsystems at mission level. It
comprises four co-dependent modules: aircraft performance, aircraft weight
estimation, LH₂ tank sizing and propulsion system performance and weight
estimation. For each one of the modules, novel and existing methodologies,
from kerosene applications, are combined to address the sizing of the
components of the LH₂ aircraft.
The research then focuses on a case study of a blended-wing body
architecture that is based on NASA’s N3-X and is powered by a TeDP system.
The airframe is scaled to accommodate more passengers as well as allow for
enough volume to fit large enough LH₂ tanks that would enable the aircraft to
meet design mission requirements.
Based on the available airframe volume, two sizing philosophies are
considered: one where only LH₂ is used for the engines and another where both
LH₂ and GH₂ are used to restrain the pressure increase of the tank during the
cruise segment. Compared to the first application, the second showcased both
significant weight savings as well as increased fuel capacity for the same
external volume occupied.
Finally, for the propulsion system, a design space exploration is performed to
identify optimum propulsion design parameters for turboelectric and partially
turboelectric distributed propulsion configurations. The different design options
are analysed based on efficiency, weight and mission level fuel economy on the
design mission and it is demonstrated that higher specific thrust designs are
more suitable for the LH₂-powered long-range application presented. The
optimum configuration identified consists of two low by-pass ratio turbofans that
are buried in the wing roots and power 12 fans installed over the aft section of
the fuselage.European Union’s Horizon 2020PhD in Aerospac
Stakeholder perceptions and project performance
No full textThe chapter highlights the importance of stakeholders as a crucial aspect in understanding project behaviour. Effective stakeholder identification and management allows project managers to understand the needs and motivations of all individuals and groups who can impact or be impacted by a project. This information is crucial in ensuring project success by helping project managers to effectively manage stakeholder expectations and build strong relationships.
The aim of this chapter is to enable the project manager to better consider and plan stakeholder management throughout the life of the project to maximise decision-making and benefits. It will elaborate on the challenges when including different stakeholder perceptions for project performance. The assumption is that it is essential to control the project’s outcome parameters through stakeholder expectations to minimise the chances of failure and maximise performance.
Engaging stakeholders in any project environment, local regional, national or global all brings separate complexities. To deliver outcomes successfully, project managers need to develop a much clearer understanding of stakeholder perceptions, expectations and priorities to enable them to cope with any changes or uncertainty as the project evolves throughout the lifecycle.Cambridge Handbook of Project Behavio
Ammonia recovery from ion exchange brine via hollow fibre membrane contactors: operational insights and product formation
No full textAmmonia removal from municipal and industrial wastewater streams is critical to ensure environmental protection. Ion exchange (IEX) processes can selectively capture NH4 +-N from wastewater, but this involves a chemical regeneration step with brine (4 % NaOH) that if not suitably managed, can lead to high chemical costs and significant environmental impacts. To achieve efficient brine management, NH4 +-N must be recovered so the regenerant can be reused over and over. This study evaluated the feasibility of hollow fibre membrane contactors (HFMC) for NH4 +-N recovery from IEX brine to enable its reuse. The nitrogen rich brine with 1190 mg NH4 +-N/L, collected from a pilot-scale IEX, was processed in two HFMC modules in series, with sulfuric acid used as the stripping solution. The HFMC operational parameters were investigated and optimised leading to 99.98 % NH4 +-N recovery efficiency. Water transport was influenced by the brine ammonia concentration: at 2000 mg NH₄+-N/L, 20 % water moved to the stripping side, whereas at 200 mg NH₄+-N/L, a 12 % decrease in stripping solution volume occurred. The highest mass transfer coefficient was 6.1 1/h with synthetic brine, increasing to 9.38 1/h with real wastewater brine, indicating enhanced efficiency with wastewater-derived solutions. The recovered ammonium sulphate salt closely matched standard composition and was free from organics, pathogens, and most inorganics and metals, making it suitable for various industrial applications. Overall, this two-step process concentrated NH₄+-N from 42 mg/L in secondary wastewater to 32 g NH₄+-N/L in under 10 h. The findings demonstrate HFMC feasibility for ammonia recovery from municipal wastewater, offering a sustainable, efficient, and economic solution without sludge production or greenhouse gas emissions, supporting net-zero targets and a zero liquid discharge strategy.This project has received funding from the Europe Union Horizon 2020 Research and Innovation Programme under grant agreement No. 776541Chemical Engineering Journa