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Annual performance of a novel configuration for an integrated solar combined cycle utilising municipal solid waste
Get PDFSansom, Christopher L. - Associate SupervisorClimate change has been a major incentive for the global power generation
industry to move towards the implementation of sustainable renewable energy
technologies in order to reduce the emissions of greenhouse gases, especially
carbon dioxide emissions. Concentrated solar power (CSP) has established itself
as one of the common renewable energy technologies for large scale power
generation. A further attractive feature of this solar technology is its hybrid
operation in the form of integrated solar combined cycle (ISCC) which facilitates
control and ensures that the power plant is available to meet demand whenever
it occurs. ISCC commonly uses natural gas to operate the combined cycle but
this CSP hybrid system also has the potential to limit its use of this fossil fuel with
a more environmentally friendly fuel, namely the produced syngas from solid
feedstock gasification which can be accomplished by further integration of the
gasification reactor with ISCC. The organic fraction of municipal solid waste
(MSW) was selected for this application, both to replace natural gas as well as
for its value as a waste management method. In the present work, the thesis
studies and contrasts four configurations of ISCC based on two factors, the type
of fuel and the level of solar thermal contribution. One configuration represents
the conventional form by using natural gas (ISCC 1) while another configuration
uses municipal solid waste (ISCC 2) and in both cases, the solar field generates
high -pressure saturated steam using parabolic trough with thermal oil. The last
two configurations are related to the research proposal for ISCC which states that
this hybrid system runs on municipal solid waste and utilises enhanced solar
thermal contribution. This enhanced thermal power from the solar field is used to
generate high-pressure superheated steam using parabolic trough with molten
salt (ISCC 3) or solar power tower with molten salt (ISCC 4). In all cases, the fuel
runs the combined cycle, and the solar field operates in parallel to provide extra
steam for the hybrid system. However, the use of gasification in ISCC 2, ISCC 3
and ISCC 4 generates extra steam for the hybrid system through syngas cooling
system which is attached to the low-pressure section of the steam turbine cycle.
In this work, models are developed to investigate the differences between the
various configurations in terms of technical and economic performances using
Spain and Saudi Arabia as case studies. The results indicate that the use of a
solar power tower in the proposed concept, ISCC 4, gave the highest electricity
production at 646 GWh with a solar share of 12.80% under Spanish weather and
644 GWh with a solar share of 15.24% under the Saudi Arabian weather.
Furthermore, ISCC 4 offered the lowest levelised cost of electricity at 28.45
/MWh for Saudi Arabia and Spain, respectively, when the
novel concept (ISCC 3 and ISCC 4) is compared to the conventional concept
(ISCC 1). The main thesis contribution was to reveal the impact of coupling the
ISCC using enhanced solar thermal power with municipal solid waste gasification
and its potential as Waste-to-Energy plant. Based on the study presented
outcomes, The proposed concept of integrated solar combined cycle (ISCC 3 and
ISCC 4) demonstrated its practicality against conventional concept (ISCC 1) due
to achieving higher performance outcomes with lower costs. The outcomes of
ISCC 2 in both countries presented slightly lower LCOE values than the novel
concept indicating that the replacement of fuel alone did not show a significant
impact against the novel concept in terms electricity production cost.PhD in Energy and Powe
Empowering knowledge dynamics: a process ontology perspective on collaborative leadership in international assignments
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This paper conceptualizes a framework for the role of collaborative leadership in the generation and distribution of knowledge by globally mobile personnel. This framework addresses limitations in existing models that often ignore the iterative and relational processes in knowledge dynamics by emphasizing collaborative leadership’s crucial role in continuously shaping these dynamic processes.
Design/methodology/approach
Adopting a theoretical approach, this study applies a process ontology to demonstrate how these knowledge dynamics interact at different levels of analysis through a continuous process of becoming. It critically reviews existing literature on knowledge transfer in international assignments (IAs), highlighting the limitations of traditional paradigms. The paper also draws on the concept of leadership-as-practice to emphasize the importance of collaborative leadership to explore these complex interactions and their implications for knowledge movement.
Findings
By applying this lens, we identify novel phenomena, including the occurrence of knowledge dynamics not only during IAs but also in anticipation of them. We uncover asymmetries of knowledge that emerge at various stages of IAs and reveal that knowledge movement in IAs is multidirectional and processual, challenging the traditional view of linear knowledge dynamics.
Originality/value
This paper introduces a novel framework combining process ontology and collaborative leadership to examine knowledge dynamics in IAs. It offers a novel perspective by moving beyond the traditional, linear understanding of knowledge transfer, emphasizing the multidirectional and dynamic nature of knowledge creation and movement. By introducing process ontology and collaborative leadership, the study challenges existing paradigms and develops theoretical propositions opening new avenues for research and theory-building in the knowledge management and global mobility literature.Journal of Global Mobility: The Home of Expatriate Management Researc
Nonlinear hydroelastic responses of a submerged horizontal plate under focused wave conditions: a cumulative fatigue perspective
Get PDFMost current analytical research on the hydroelastic interaction between water waves and submerged horizontal elastic plates remains within the scope of linear theory due to the underdevelopment of mathematical methods for solving nonlinear problems. To address this gap, this work employs an approach that combines computational fluid dynamics (CFD) with computational solid mechanics (CSM) to dynamically simulate the fully coupled nonlinear hydroelastic interactions between ocean waves and a submerged horizontal plate. This research highlights the significance of nonlinear point responses of a submerged horizontal plate under focused wave conditions. A phase-based harmonic separation method (i.e., phase-decomposition method) is used to isolate wave amplitude and force harmonic components in complex wave scenarios. This approach allows for the clean delineation of individual harmonics from the total wave force by controlling the phase of incident focused waves and is for the first time applied to the response analysis of elastic structures. This paper successfully used the phase-decomposition method to separate the individual harmonics of the point displacement of a horizontal elastic plate, directly demonstrating the significance of nonlinear responses. Additionally, the impact of plate rigidity, which relates to natural frequency, on nonlinear responses is investigated. The results indicate that plates with a certain dimensionless plate rigidity will exhibit more significant nonlinear responses. By cleanly separating each individual harmonic response, this study provides new insights into the nonlinear hydroelastic responses of a horizontal plate interacting with water waves and offers a new perspective on fatigue analysis, underscoring the importance of nonlinearity for future engineering designs.The authors are very grateful for the financial support from the UK EPSRC [Grant Nos. EP/T026782/1; EP/V050079/1; and EP/V040235/1].Physics of Fluid
Unveiling the truth of interactions between microplastics and per- and polyfluoroalkyl substances (PFASs) in wastewater treatment plants: microplastics as a carrier of PFASs and beyond
Get PDFMicroplastics (MPs) and per- and polyfluoroalkyl substances (PFASs) are ubiquitous contaminants in environments, yet their co-occurrence and interactions remain insufficiently understood. In this study, we confirmed the concurrent presence of MPs and PFASs and their distinct distribution patterns in a wastewater treatment plant (WWTP) through a comprehensive sampling and analysis effort. Significant correlations (p < 0.05) were observed between specific types of MPs and PFASs, suggesting their shared sources. Moreover, MPs were identified as carriers of PFASs, with PFAS concentration ranging between 122 and 166 ng/g, predominantly consisting of perfluorooctanoic acid (PFOA) and perfluorobutanoic acid (PFBA). The laboratory verification experiment revealed that PFASs could be leached from MPs in aqueous environments, in which commercial MPs exhibited higher leaching potential, with the highest combined concentration of perfluorooctanesulfonate (PFOS), PFOA, and PFBA reaching 10.4 ng/mL. PFOS demonstrated a desorption efficiency exceeding 120% in sorption/desorption experiments, confirming its release from the MPs themselves. These results highlighted the dual roles of MPs as both carriers and sources of PFASs. The identified contaminant profiles and correlations between MPs and PFASs across different matrices in WWTP provide valuable insights and form a basis for further research into proactive measures to effectively mitigate their environmental contamination.Biotechnology and Biological Sciences Research Council, National Natural Science Foundation of China, European CommissionThis research was supported by the National Natural Science Foundation of China (no. 32061133001), and we acknowledge the cooperation between China and the EU through the EiCLaR project (European Union’s Horizon 2020, no.965945). This work was also supported by the National Natural Science Foundation of China (U20A20322).F.C. acknowledges the funding received through BBSRC NIBB’s Environmental Biotechnology Network (EBNET, grant reference BB/S009795/1Environmental Science & Technolog
High-rate, fracture testing methods
Get PDFIt is generally easier to break alloys at high speeds; in other words, fracture toughness reduces as strain rate increases. Understanding of these dynamic properties, by experimentation, reduces excessive conservatism in structural design, allowing for safe life extension of existing components and more efficient new constructions. This work investigates procedures to determine fracture toughness at elevated loading rates. Specific testing, used examples of different properties from Zinc, Aluminium and SA508-III pressure vessel steel, highlighting challenges in standard methods.
Two methods of ‘rapid’ toughness testing have been contrasted – pendulum (Charpy) and servohydraulic (Very High Speed [VHS] Instron) test rigs. Charpy pendulums have a set energy input, hence a non-constant speed. Servohydraulic machinery adds energy to the system, maintaining speed. Both methods utilised sub-sized (10mm square bending specimens) specimens are recommended for high speed, minimising inertial effects and align with load capacities of high-rate instrumentation.
Elevated speeds also make crack growth more difficult to monitor, compared to well understood static methods. Normalisation crack length monitoring (as recommended in standards) and a linear growth assumption from peak load have been utilised in this testing. Both methods produce similar crack length histories. Normalisation method anticipated the same crack growth initiation as peak load and showed a non-linear crack growth that aligns well with fracture surface features. However, the normalisation method is open to personal interpretation to fit data to a standard model.
Results showed both testing methods to be dynamically invalid for brittle materials (Zinc and SA508-III steel at low temperature). Dynamic invalidity occurred as fracture occurred before (less than 93µs) kinetic energy effects are minimised - a requirement from standards for valid high-rate testing.
Ductile materials (Aluminium and SA508-III steel at high temperature) were dynamically valid. Peak loads in Charpy data were clipped by relatively low sample rate. Peak loads in VHS testing were emphasised by high levels of ringing caused by impact shockwave resonating through the test rig. This let Charpy and VHS data to present different responses. Aluminium testing (low stiffness) loaded slow enough and damped ringing enough to produce comparable toughness data. Steel (higher stiffness) experienced these effects so much that data was incomparable. Improved system by higher sample rate Charpy instrumentation and higher mass and rigidity in the VHS test rig would reduce ringing (signal noise) and allow for better identification of accurate material response. The discrepancies between testing machines overwhelmed the effect of fixed energy input or speed controlled procedures.Engineering and Physical Sciences Research Council (EPSRC)EPSRC ref. EP/S023844/1AWE, DNV Energy Systems, UK, Nuclear Energy Futures CDTDefence and Security Doctoral Symposia 2024 (DSDS24
Guided by principles or rules: a Delphi study on how safety professionals frame safety practices
Get PDFThis study explores how safety professionals conceptualize and articulate safety practices, examining how their framing influences actions, facilitates learning from failures, and impacts overall safety outcomes. Twenty-nine safety professionals participated in a Delphi study, which included three online workshops and three rounds of surveys. Eighteen safety practices were developed, framed as both rules-based and principles-based practices. Survey results indicated that both rules-based and principles-based practices were considered essential for achieving safety, with their relative balance likely being context-dependent. While all practices were considered important for preventing accidents, those framed as principles were seen as more challenging to implement but ultimately more effective, especially in complex situations. Better understanding of the way in which safety practices are framed has significant implications for the development of safety standards, guidelines, and recommendations.We would like to thank Royal Academy of Engineering, UK for financial support for this work.Safety Scienc
Muslim employees’ religious and intersectional identities as sources of discrimination: how deeper understanding can improve managerial practice
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This study aims to explore how intersecting identities shape experiences of workplace discrimination faced by Muslim employees in Catalonia, Spain. We seek to understand the interplay of religion, ethnicity, gender and age in their employment experiences in order to improve managerial practices.
Design/methodology/approach:
The research employs a qualitative approach, conducting in-depth interviews with 39 diverse Muslim employees in Catalonia through convenience and snowball sampling to support an intersectional analysis.
Findings:
Findings reveal that Muslim employees navigate a workplace environment where their experiences of discrimination are shaped by intersecting identities including religion, age, gender and ethnicity which become salient at various stages of their careers, prompted by HRM practices such as recruitment, selection and promotion. Their experiences as recipients of these practices illuminate the complex ways in which intersecting identities shape the experiences of discrimination. The study reveals the hiding of their religious identity, giving up on traditional career paths, seeking social support from other Muslims and emphasizing privileged identities, to deal with discrimination.
Originality/value:
This study deepens understanding of the complexity of religious identity in minorities and explores its role in workplace discrimination. In particular, the research sheds light on the psychological impact in the form of feelings of guilt and shame which arise from coping strategies such as concealing religious markers which are adopted by these employees in response to organizational and managerial practices. Lastly, the paper stresses the need for intersectional approaches in order to improve effectiveness of HR policies and managerial practices.Journal of Managerial Psycholog
Unlocking circular economy: overcoming roadblocks to circular healthcare supply chain in Indian healthcare
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The circular economy concept in the healthcare supply chain can demote using single-use devices by reprocessing, reusing or recycling. India is the most populous country in the world and has numerous challenges to implementing a circular economy in the healthcare supply chain. The objective of this study is to identify and analyse the roadblocks to circular healthcare supply chains in the Indian context.
Design/methodology/approach
The contribution of the manuscript is to the healthcare supply chain in adopting a circular economy and prioritizing the roadblocks using Fuzzy FUCOM and Fuzzy Bonferroni Mean Operator. A sensitivity analysis is performed to check the robustness of the results obtained.
Findings
The finding of this study suggests that regulatory roadblock is a more important roadblock in adopting the circular economy in the healthcare supply chain. It is expected that the government should formulate precise and consistent guidelines for the implementation of a circular economy in the healthcare supply chain. In addition, for faster implementation, tax rebate policy should be framed for the industries that are taking the initiative to implement a circular economy in their system.
Practical implications
This study explores and prioritizes twenty secondary roadblocks categorized into five primary roadblocks that will enhance the motivation of healthcare industries to become green and circular and contribute to the sustainability in healthcare sector. The government agencies should also take initiatives to create awareness about the circular economy among all the stakeholders.
Originality/value
This research is beneficial for policymakers, researchers, and industrial practitioners and is recommended based on current findings to facilitate the implementation of a circular economy in the healthcare sector.Journal of Advances in Management Researc
Emergent defence organising
Get PDFDefence Command and Control (C2) relies on socio-technical systems and hierarchical methods of organising functional elements. This paper builds from threat projections of future operational complexity to explore the Defence organisational limitations in coping with complex problems, and what type of organisational changes could help Defence start to achieve advantage within the inherent complexity of conflict. Through an understanding of some of the historical organisational contexts, the paper provides visualisations of the most significant C2 organisational capability gaps and proposes the development of a more effective Defence enterprise, using emergent relationships between loosely affiliated functional groups to deliver competitive advantage in complex future operating environments.HQ Army, EP(A)Defence and Security Doctoral Symposia 2024 (DSDS24
Dark and bright repercussions of COVID-19 pandemic on international business: a systematic literature review and future research agenda
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As a global pandemic of historically significant scale, COVID-19 and its impact on global business activities have gained significant scholarly attention in the international business (IB) domain. This study aims to review and consolidate the IB research findings on the COVID-19 crisis, considering both the literature on the dark and bright repercussions for firms.
Design/methodology/approach
The authors systematically reviewed and synthesized a sample of 87 scholarly articles published in major IB journals from 2019 to 2022.
Findings
This review paper highlights the important domains – including global value chains, digitalization and varieties of functional areas – that have been substantially affected due to the widespread disruptions caused by the pandemic. This study also discusses future avenues for extending the work on the dark and bright sides of crisis management.
Originality/value
Applying the overarching concept of the bright and dark sides of the COVID-19 pandemic, the authors developed a framework that highlights the important knowledge gaps and points to future research directions. This review also suggests the salient methodological and contextual avenues potentially suited for future IB research on the pandemic and similar crises.Multinational Business Revie