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Modelling the Diffusion Kinetics of Bioactive Compounds Released from Protein-polysaccharides Composites
No full textThe rheology of phase-separated biopolymers is characterised by distinct viscoelastic properties, with one biopolymer typically forming a continuous phase and the other a dispersed phase. This structural arrangement significantly impacts diffusion, as the rigidity and network density of the continuous phase influence the rate and extent of bioactive compound migration. By modifying these rheological properties, the release profiles of encapsulated or entrapped molecules can be finely tuned, making rheology a crucial factor in designing controlled diffusion systems within biopolymer matrices. In this study, phase separation in biopolymer gels was investigated using blending law modelling, with a focus on the diffusion behaviour of vitamin B6 as a bioactive compound within the matrix. While previous studies primarily utilised blending law modelling to predict solvent partitioning and phase behaviour in mixed biopolymer systems, our research extends this approach as an alternative to traditional diffusion models. By examining how matrix structural properties, such as elasticity and topology, influence diffusion, we provide insights into how biopolymer interactions affect the release kinetics of bioactive compounds. This approach emphasises the critical role of matrix architecture in functional food applications, allowing for controlled release and improved bioavailability of encapsulated compounds. In the first experimental chapter of this thesis, gelatin–agarose phase-separated composites were utilised to investigate pyridoxine diffusion using blending law modelling. The phase behaviour of these biopolymer composites was thoroughly analysed, employing a rheometer to characterise the rheological properties and confirm the lack of interactions between the polymers, affirming phase separation. Structural properties were further examined using Fourier-transform infrared (FTIR) spectroscopy, wide-angle X-ray diffraction (WXRD), confocal laser scanning microscopy (CLSM), and polymer blending laws. These combined microscopic, spectroscopic, and thermomechanical observations confirmed that gelatin formed a continuous phase, while agarose existed as a dispersed phase within the composite. Additionally, increasing agarose concentration resulted in heightened rigidity of the dispersed phase. Effective phase concentrations of each polymer were calculated using blending law modelling, allowing for the determination of the diffusion coefficient for each phase and, subsequently, an overall diffusion coefficient for the composite based on the phase behaviour. Furthermore, modern diffusion modelling techniques for cylindrical gel geometries were applied to obtain experimental diffusion coefficients from the composites. The close agreement between the diffusion coefficients derived from blending law modelling and modern diffusion modelling highlights the suitability of the blending law model as a reliable alternative for estimating diffusion behaviour in biopolymer composites.In the second chapter of this thesis, the study conducted a comprehensive exploration of the versatility of the blending law model to assess its applicability in estimating diffusion coefficients in various biopolymer systems. Concentrations of agarose and gelatin were systematically adjusted to establish a phase-inverted bicontinuous structure within the composites. This adjustment resulted in a significant alteration in phase behaviour, wherein both gelatin and agarose exhibited characteristics typical of a continuous phase. Consequently, agarose emerged as the continuous phase, while gelatin was relegated to the dispersed phase. This phase inversion phenomenon was characterised as operating under isostress conditions. To accurately determine the diffusion coefficients for the phase-inverted bicontinuous composites, relevant theoretical blending law models were employed and compared against coefficients derived from conventional diffusion modelling techniques. This dual methodology facilitated rigorous cross?validation of the calculated diffusion values, offering valuable insights into the accuracy of blending law modelling in systems with complex phase topologies. The structural properties of the phase-inverted bicontinuous composites were analysed extensively through a combination of Fourier-transform infrared (FTIR) spectroscopy, wide-angle X-ray diffraction (WXRD), confocal laser scanning microscopy (CLSM), and dynamic oscillatory testing. These integrated microscopic, spectroscopic, and thermomechanical analyses confirmed that gelatin and agarose formed a bicontinuous network, with agarose primarily constituting the continuous phase and gelatin occupying the dispersed phase. The phase inversion was distinctly observed in the exhibited isostress behaviour. The data obtained not only demonstrated the effectiveness of blending law modelling in calculating diffusion coefficients for complex biopolymer systems but also underscored its potential as a robust alternative to traditional diffusion modelling. This is particularly relevant for applications that necessitate precise diffusion control in the fields of food science and biopolymer-based functional materials. modelling in calculating diffusion coefficients for complex biopolymer systems but also underscored its potential as a robust alternative to traditional diffusion modelling. To further validate the developed blending law modelling, a composite system of whey protein and agarose was prepared, with whey protein forming the continuous phase and agarose as the dispersed phase. Gelation of the whey protein was achieved through controlled heat treatment at a neutral pH, allowing for the formation of a stable network that aligns with the phase-separated structure required for blending law application. This composite system demonstrated that blending law modelling could accurately predict the diffusion coefficient within a new biopolymer matrix, further supporting its novelty as an approach for calculating diffusion coefficients across diverse biopolymer systems. The results reinforce the blending law model's potential as a versatile, alternative method to traditional diffusion modelling for complex food and functional material applications.To extend the validation of blending law modelling, composites of bovine serum albumin (BSA) and agarose were prepared, where BSA served as the continuous phase and agarose formed the dispersed phase. This configuration confirmed that blending law modelling could effectively predict diffusion coefficients within a diverse range of biopolymer matrices. Throughout this research, blending law models were systematically employed as an alternative to diffusion modelling, offering new insight into diffusion coefficient estimation for phase-separated composites. To challenge the model's limitations, a second BSA–agarose composite was created, deliberately structured to fall outside the traditional scope of blending law applicability. In this configuration, gelation was restricted to the agarose phase, while BSA remained in a non-gelled state, entrapped as discrete particles within the continuous agarose matrix. Structural analysis using Fourier-transform infrared spectroscopy (FTIR), wide-angle X-ray diffraction (WAXD), confocal laser scanning microscopy (CLSM), and dynamic oscillatory shear testing confirmed the distinct phase structure, with a continuous agarose phase and dispersed BSA particles. The Lewis–Nielsen equation was applied to assess the thermomechanical properties and diffusion coefficients within this composite, offering an alternative calculation method. Comparison of diffusion coefficients derived from the Lewis–Nielsen approach with traditional diffusion modelling showed a close correlation, highlighting its potential as an innovative method for evaluating diffusion in systems with non-traditional phase structures. These findings indicate that the Lewis–Nielsen model can serve as a novel alternative, expanding the scope of diffusion coefficient estimation in complex biopolymer matrices.</p
Speculative Carbon Cultures? Regenerative Finance and Climate Action
No full textIn global climate governance, carbon as a metaphor has been made to serve multiple political, economic and social aims. The prevalence of carbon-based molecules in greenhouse gases, particularly carbon dioxide, has meant that “carbon” has come to represent greenhouse gases more broadly, often through mechanisms such as “carbon offsets”, “carbon markets”, “carbon taxes” and “carbon footprints”. In this way, “carbon” has taken on a cultural meaning far outstretching the strictly scientific definition of carbon as chemical element. Further, the use of market-based measures within global climate governance has meant that carbon has increasingly become financialised, datafied, and abstracted from its biophysical reality. In many ways, carbon has come to shape the edges of our imaginaries in climate governance, and thus intervening within and transforming global climate governance requires reimagining attachments to and practices around carbon.
This thesis draws on energy and carbon cultures literature (Hickey-Moody 2019; Sheller 2014a; Szeman and Boyer 2017) to introduce the concept of “speculative carbon cultures”. Speculative carbon cultures hold a tension between two contradictory forms. On the one hand there is the speculative practice of imagining alternative carbon futures, creating change through new energy imaginaries. These speculative carbon cultures are open and may help to transform prevailing relationships to carbon and wider ecosystems. On the other hand, this framework draws attention to how the carbon cultures of market speculation, financialisation and datafication have dominated climate governance to date. Throughout this thesis I explore this tension through a detailed case study of an emerging climate movement, the Regenerative Finance or “ReFi” movement.
As the ecological crisis brought on by climate change deepens, diverse groups are turning to new tools and technologies to support and engage their visions for the future. One such group is the Regenerative Finance or “ReFi” movement, who use blockchain technology towards climate action. Members of these ReFi communities see a need to redefine contemporary understandings of value, finding new possibilities for connecting economic value with ecological value. For ReFi projects this often works through market-based measures, aimed at internalising the costs of environmental damage within economies, by bringing carbon credits or climate data onto the blockchain or using web3 tools towards climate governance.
While many ReFi initiatives are focused on improving carbon markets and broader socioeconomic structures, for the participants within these programs they are deeply personal. For these groups, ReFi offers participants the opportunity to reimagine their relationships to energy and climate futures and to support everyday participation in spaces that have typically been the remit of larger businesses and governments. Through my thesis, I demonstrate how ReFi members’ values around adaptation and playfulness are not just about empowering citizenship in the singular, but citizenship as a plural project. Blockchain, serving as an institutional technology, furnishes ReFi participants with the tools to experiment creatively and reshape institutions themselves, constituting a form of institutional play that imparts valuable insights for future social movements.
Critics of ReFi, however, see that, instead of pointing towards new, more equitable and participatory futures, by prioritising market-based understandings of value, ReFi further locks ecological systems into capitalist structures of extraction, perpetuating trends towards carbon financialisation. Without a justice-based lens, the political imaginaries of ReFi may perpetuate current imbalances of power in global climate governance. Issues of crypto-colonialism (Howson 2020b), cryptosecessionism (I. Simpson and Sheller 2022), and the dominance of existing power structures within the movement, such as venture capital, are deeply harmful not only to the movement’s overall climate goals, but to the notion of empowered climate citizenship more broadly. Equally, there are significant limitations to the movement’s central goal of transparency (Ananny and Crawford 2016; Goldstein 2022; Hull, Gupta, and Kloppenburg 2021).
Drawing on a series of interviews with core members of Regenerative Finance projects globally, I argue that ReFi as a movement epitomises the tension within speculative carbon cultures. Through their commitment to institutional play, ReFi members experiment with new attachments to and practices around carbon. However, through their reliance on carbon markets and cryptocurrencies, they perpetuate trends towards carbon financialisation and market speculation within global climate governance. Thus, ReFi embodies the two sides of speculative carbon cultures, and ultimately, the change-making potential of the movement may depend on which form prevails.</p
Transplanting TISSA: "New Voices" in Trans-Tasman social work research
No full textIn this article, we reflect on the development of 'New Voices in Social Work Research', a PhD research symposium that has been transplanted from the European TISSA ("The International Social Work and Society Academy") model to the Australian and Aotearoa New Zealand contexts. We also explore our experience of working collaboratively with academics, researchers, and the emerging community of doctoral scholars who are engaged with the 'Australia and New Zealand Social Work, Welfare and Research' (ANZSWWER) organisation. In our reflection, we consider the early stages of the New Voices in Social Work Research symposium and argue the importance of a space for PhD and Early Career Researchers (ECRs) to build research capabilities and provide opportunities for research dissemination. Finally, we introduce ideas for further research in order to strengthen the 'New Voices in Social Work Research' initiative to better support doctoral researchers in social work education in Australia and Aotearoa New Zealand.</p
Digital Media and Behavioural Addiction: Where does use become Problematic?
No full textBackground: Digital media has proliferated through the cultures of the developed world to the point where it touches nearly every facet of modern life. While its benefits are undeniable, concerns have abounded regarding its possible negative effects on wellbeing, especially for individuals exhibiting problematic digital media use (PDMU). PDMU is often conceptualized using the behavioural addiction model, which likens it to substance addiction. According to this model, compulsive and impulsive behaviours driven by digital media dependency lead to adverse consequences similar to those experienced in substance abuse. Despite its widespread use, the behavioural addiction model faces criticism regarding its validity and applicability, sparking a need for deeper investigation. Research objectives: This PhD project, structured as a PhD with Publications, is designed to assess the structure of Problematic Digital Media Use (PDMU). The overarching research objective (ORO) is to determine the structure of PDMU and establish its alignment with the behavioural addiction model. To achieve this, the project sets forth four specific objectives: firstly, to identify the manifestations of Internet Gaming Disorder (IGD); secondly, to delineate the manifestations of Social Media Addiction (SMA); thirdly, to explore the interactions between the symptoms of SMA and IGD and their impact on comorbidity and well-being; and fourthly, to develop strategies for clinicians to manage digital media use effectively, thereby maximizing positive outcomes and minimizing negative effects. Research questions: To achieve the research objectives, a series of research questions have been formulated to guide both the overall investigation and the specific areas of interest. The overall research question (ORQ) asks, “What is the structure of PDMU, and does it support the behavioural addiction model?” This is complemented by specific research questions focused on the nuances of digital addictions: (SRQ1) “What are the expressions of Internet Gaming Disorder and how do they relate to wellbeing?”; (SRQ2) “What are the expressions of Social Media Addiction and how do they relate to comorbid addiction?”; (SRQ3) “In what ways do the symptoms of Social Media Addiction interact among themselves and influence comorbid distress, both cross-sectionally and over time?”; and (SRQ4) “In what ways do the symptoms of Internet Gaming Disorder interact among themselves and influence comorbid distress, both cross-sectionally and over time?”. Methods: To address the specific research questions, this PhD project presents four research studies using three different datasets. Each employed survey data gathered from archival datasets in the case of empirical study one [n = 1032, Mage = 24, SDage = 7, males = 503 (48.7%), females = 529, (51.3%)], and through this projects own data collection in the case of empirical studies two [n = 968, Mage = 29.5, SDage = 9.36, males = 622 (64.3%), females = 315, (32.5%)], three and four [n = 462, Mage = 30.8, SDage = 9.23, males= 320 (69.3%), females=134, (29%)]. In empirical studies one and two, participants were measured on their experience of IGD and SMA symptoms respectively, before latent class analysis was undertaken to identify any homogenous subgroups of participants within the data and examine how they experienced IGD/SMA, profiling IGD and SMA experience as per SRQ1&2. Subsequent chi-square analyses for empirical study one and ANOVA analyses for empirical study two were employed to fulfil the second conditions of these questions, examining whether any identified subgroups also differed in terms of their experience of risk factors and comorbidities. In empirical studies three and four, participants were measured on their experience of IGD and SMA symptoms respectively, with their experience of distress measured secondarily. Subsequently, longitudinal network analysis was undertaken to determine how each symptom of IGD/SMA respectively interacted with eachother, answering the routes by which they influenced eachother, and how IGD/SMA interact with distress, both cross-sectionally and across time answering SRQ3&4.
Results: For both IGD and SMA in empirical studies 1 and 2, distinct, severity subgroups of symptom experience were discovered and their associations with numerous indicators of wellbeing assessed. Social engagement was negatively associated with higher risk classes of IGD. Furthermore, a hierarchy of substance/behavioural addictions associations with SMA risk class was identified, with internet and shopping addiction bearing the strongest positive association with high SMA risk class. This both established concurrent validity and provided insights into the nature of PDMU fulfilling the ORQ. In empirical studies 3 and 4, Both the IGD and SMA symptoms formed stable networks cross-sectionally and longitudinally, distinct from distress, but linked to it via mood-modification. These results allow for more granular examination of the relationship between varying symptoms of IGD and SMA, and their association with distress, allowing for examination of the nature of PDMU answering the ORQ. Conclusion: The results of this PhD project support the validity of the behavioural addiction conceptualization of problematic digital media use (PDMU). Differing symptoms show greater predictive validity across internet gaming disorder (IGD) and social media addiction (SMA), with mood modification serving as the linking symptom to comorbid mental illness. Specifically, empirical studies 1 and 2 identified distinct expressions of IGD and SMA, respectively, with varying severity levels. Results suggest a single, unitary behavioural addiction model for PDMU. Additionally, empirical studies 3 and 4 found that symptoms of SMA and IGD cluster more tightly amongst themselves than with distress, contradicting theories of them being secondary symptoms. Despite fluctuations in mean levels over time, both IGD and SMA remain stable in symptom presentation, underscoring their interconnected nature. Overall, these findings enhance our understanding of PDMU and reinforce the behavioural addiction model in its context. Originality/value: This PhD project provides a novel, comprehensive examination of PDMU by integrating profiling, network modelling, and longitudinal analysis. The findings support the behavioural addiction model, demonstrating that IGD and SMA are distinct yet interconnected behavioural addictions with stable symptom networks and specific pathways to distress. By addressing long-standing debates, this research contributes to the theoretical understanding of PDMU and equips clinicians with actionable insights for treatment and prevention. These results have implications for clinical practice, policy development, and the broader understanding of how digital media impacts mental health.</p
Effects of Pyrolysis Conditions on Biosolids Biochar and Heavy Metal Immobilisation in Soil
No full textBiosolids, or the treated sewage sludge is the major by-products obtained from wastewater treatment plants and contain different types of organic and inorganic nutrients. Recently, the beneficiary use of biosolids has significantly increased in Australia. However, the presence of heavy metals, pesticides, contaminants and user regulations in the states limit the direct application of biosolids to agricultural land. The research presented in this thesis focuses on the variation in properties of biosolids during pyrolysis processes producing the carbon-rich solid materials, the biochar from biosolids. This research explores the effects of different pyrolysis conditions particularly the pyrolysis temperature and carrier gases on the physicochemical and structural properties of biochar. The effects of pyrolysis temperature (400, 500, and 600 °C) and two different carrier gases (nitrogen, N2 and carbon dioxide, CO2) were determined on biochar, derived from biosolids. The physico-chemical properties were determined by the analytical methods of pH, EC and CEC, FTIR, TGA and CHNS/O analyser, while SEM, BET and XRD were performed to identify the surface images, surface area and surface minerals. The results indicate that high pyrolysis temperature has a less functional group, high surface area, pH and ash content. Biochar produced under CO2 showed higher surface area, and more aromatic and hetero-aromatic structures, while biochar produced under N2 was more alkaline and had higher salinity content. Moreover, biochar produced from biosolids is expected to have a higher metal content after pyrolysis. We measured the total concentration, plant bioavailability and chemical fractionation of heavy metals in resulted biochar using USEPA 3050B, BCR and DTPA methods. Total metal concentration is increased with temperature and the bioavailable metals did not show any significant difference under different pyrolysis conditions. However, biochar produced at higher pyrolysis temperatures under N2 atmosphere can reduce the higher ecological risk of HMs in biochar. Furthermore, P fractionation and the chemical nature of P were investigated in resulted biochar using Hedley chemical sequential extraction and 31P liquid NMR analysis. This method was used to identify plants’ P reactivity or availability and the chemical nature of P compounds. The study determines increased P fixation with higher pyrolysis temperature and decreased short-term P-bioavailability, while the carrier gas shows minimal effects. Biochar produced in CO2 had slightly higher water-soluble P, NaHCO3-Pi, NaOH-Pi and Residual- P than prepared in N2, while HCl-P showed the opposite trend. Additionally, the predominant molecular configuration of P was present in the inorganic form identified by 31P liquid NMR spectra, while organic P transformed into inorganic P with increasing pyrolysis temperature. Finally, the effects of P-rich biochar in the remediation of Pb-contaminated soil were determined. The result identifies the effectiveness of biochar, where we also used traditional phosphate amendments (MCP & NTS) for the immobilisation of Pb-contaminated soil in situ. The results showed that the leachable Pb (determined by TLCP) had a significant after biochar addition, while no significant result was found in bioaccessible Pb similar to traditional phosphate amendments. Overall, the results indicate that the observed changes in properties of biochar can be associated with the characteristic of lower pH, lower Electrical Conductivity (EC) and leachable-Pb in the biochar produced under different environments, although other mechanisms including the formation of stable Pb compounds might play an important role.</p
Mandarin-Speaking Interviewees’ Understanding and Perceptions of Police Interviewing Mediated by Interpreters
No full textScholarship on police investigative interviewing has advanced considerably over the past few decades. Significant attention has been paid to the strategic wording and formulation of police questions that aim to obtain accurate and comprehensive information from interviewees in monolingual English settings. Some types of police questions have been argued to be productive for gathering information, while others are classified as non-productive. As interpreter-mediated police interviews in bilingual settings are receiving increasing attention, studies of police interpreting have revealed semantic and pragmatic shifts in interpreted police questions and difficulties in achieving interpreting accuracy in police settings. However, existing scholarship has mainly adopted the perspective of the source language to examine whether police questions are faithfully interpreted into the target language. As yet, it is largely unknown if English police questions, either productive or non-productive, work as intended on interviewees in the target language and culture after language mediation. In addition, significantly fewer studies have focused on English–Mandarin police interpreting. Research on this language combination is urgently needed in the multilingual Australian context, where Mandarin is currently the second most spoken language in the country. This thesis, therefore, adopts Mandarin-speaking interviewees’ perspectives and Chinese linguistic and cultural frameworks to explore their perceptions of police questions rendered into Mandarin from English in investigative interviews in the Australian context.
This empirical research is exploratory in nature and adopts a qualitative approach. It consists of two sequential phases with two groups of participants: (1) a discourse analytical study of Mandarin trainee interpreters’ renditions in a simulated English–Mandarin police interview, and (2) a survey of native Mandarin-speaking interviewees’ perceptions of the Mandarin renditions of English police questions. The first phase is a simulation of police interviewing mediated by six trainee interpreters from RMIT University. Through pragmatic and syntactic analyses, it was found that some renditions would either fall into a different functional question type or exert a different level of control in the Chinese context to the original in English. Other pragmatic deviations were associated with the focus, neutral wording, and tone of the police questions. The renditions featuring these traits form the basis of the research instrument for the survey in the second phase: a monolingual Mandarin police interview and questionnaire to collect the perceived pragmatic features of the selected renditions. In the survey, individual native Mandarin-speaking respondents (n=21) listened to the audio recording of the Mandarin police interview segment by segment and responded intuitively to the turns containing the selected renditions as if they were in the exchange. Their perceptions collected by items (administered online) were analysed using descriptive statistics, and their oral responses to flexible probing elements were coded using an inductive approach.
Findings show that the respondents’ perceptions deviated from the pragmatic features of the English questions in the aspects of the information sought, the controlling force over the answer, question focus, neutral wording, and tone. Overall, different ways of interpreting the same police questions led to different perceptions and, therefore, different responses. This study argues that linguistic, interpreter-related, interviewee-related, and contextual factors may have caused the pragmatic deviations. For police interpreting, the research highlights the difficulty of recreating the pragmatic features of police questions across languages and the importance of interpreters’ pragmalinguistic knowledge of their working languages. For police investigative interviewing, it suggests that English-speaking police interviewers should be aware of possible pragmatic deviations in bilingual interviews by adding follow-up questions to obtain further details. In addition, the differences between what was perceived by the respondents in the study and what has been argued in the existing scholarship point to the need for larger-scale research in future. It is hoped this initial step will encourage further research in the area of interpreter-mediated police interviewing between English and Mandarin, as well as other languages.</p
Wide-band variable transversal phase-shifter
No full textWe present a novel broadband phase-shifter based on a transversal filter configuration. This approach allows flexible control of the amplitude response while providing continuous variation of a linear phase slope. Numerical examples, both ideal and using practical RF components are presented and practical challenges in realising the phase-shifter are identified.</p
I think I might be gay
No full textFor young people struggling with issues around their sexuality, 'coming out' to their families, schools and communities can be traumatic. The alarming statistics for youth suicide, risk-taking behaviours and mental health concerns reflect the alienation and harassment felt by gay, lesbian, bisexual and transgendered young people as they wrestle in isolation with the difficulties of 'being different'. They need families, schools and communities to provide support, understanding and affirmation; and to be their allies against homophobia. Maria Pallotta-Chiarolli has compiled a valuable guide for all those whose lives are affected by a young person coming out. In this work she includes first-hand accounts from families, schools and communities across different socioeconomic levels, diverse regions and many cultural backgrounds. She also provides vital suggestions and advice for those at the coalface of this issue - parents of young people who need to come out, high-school teachers and community leaders - as well as effective responses and strategies for dealing with homophobia in any environment.</p
Selective removal of Fe impurities in the recovery of rare earth elements from carbonatite tailings using chemical routes
No full textThe increasing demand for rare earth elements (REEs) has led to the exploration of mining tailings as a potential secondary source. This study offers novel insights into the recovery of REEs from Fe-rich mine tailings sourced from a weathered carbonatite deposit. The REEs were recovered by selectively removing Fe impurities after acid-leaching. The paper details the comprehensive methodologies employed, including initial hydrochloric acid leaching and variable optimization such as acid concentration, liquid-to-solid ratio, temperature, and time. An alkali pre-treatment using NaOH was also investigated to assess its impact on the efficiency of REEs recovery. The study reveals that pH plays a significant role in the selective removal of Fe impurities and offers avenues for the production of high-purity, industry-grade REEs. The work is particularly ground-breaking in its exploration of selective Fe removal using a combination of dilute ammonium hydroxide and ammonium chloride. Through this method, a significant milestone was achieved: the precipitated solid primarily contained Fe (>96%), with minimal loss of REEs (only 0.22%) at a solution pH of 3.25 at 40 °C. This study is the first to demonstrate such high selectivity in the removal of Fe from acid leach liquors of this nature
A Novel Asymmetric Hybrid-Layer Del-Shaped Rotor Interior Permanent Magnet Motor for Electric Vehicles
No full textInterior permanent magnet (IPM) motors have garnered widespread popularity in electric vehicle (EV) applications due to their distinctive advantages, including superior torque density, high efficiency, and a wide speed range. In this work, the asymmetric hybrid-layer del-shaped ( ∇ -shaped) IPM motor is introduced to enhance the torque capability of the benchmark IPM motor designed for EVs. The proposed motor incorporated an asymmetric PM configuration, integrating hybrid-layer PMs arranged in a ∇-shaped pattern. To achieve the design objectives, the initial motor design was optimized using a Genetic algorithm, considering sensitivity analysis to precisely attain the targeted torque capability based on EV-specific objective functions. Subsequently, the electromagnetic performance of the proposed motor was analyzed through finite element analysis, and a comparison was made with a symmetric IPM benchmark structure. The results clearly demonstrate the superiority of the proposed asymmetric IPM motor, which exhibits significantly higher average torque, attributed to the effective utilization of the magnetic field shifting effect. Furthermore, a notable reduction in torque ripple was revealed, with this motor experiencing only 9.62% torque ripple, rendering it a suitable choice for EV applications. Additionally, enhanced magnet utilization resulting from the asymmetric permanent magnet configuration in the proposed motor was observed. The overall efficiency of the asymmetric IPM motor was enhanced, reaching an impressive 96.68%. Consequently, the proposed asymmetric IPM motor represents an eminently practical and efficient solution for EV applications