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Phase-Field Simulation of the Creep Mechanism in the AZ31 Magnesium Alloy Under Discontinuous Dynamic Recrystallization Dominance
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The data presented in this study are not publicly available at this time as they form part of an ongoing research project. Data may be made available in the future upon reasonable request and after the completion of the related study.Discontinuous dynamic recrystallization is a critical microstructural evolution mechanism during high-temperature deformation, influencing material properties significantly. This study develops a two-dimensional phase-field model to predict steady-state creep rates in the AZ31 magnesium alloy, focusing on DRX during creep. To enhance simulation accuracy, initial microstructures are generated from optical microscopy data, enabling simulations at larger scales with higher representativeness. A novel nucleation methodology is implemented, eliminating the need for nuclei order parameter adaptation, improving computational efficiency. Finite element analysis (FEA) is integrated to capture initial instantaneous deformation. The Kocks–Mecking model is employed to describe the evolution of average dislocation density, accounting for work hardening and dynamic recovery within the initial polycrystalline microstructure. Instead of conventional creep testing, impression creep, a cost-effective alternative, is used for validation. This method provides constant stress and steady penetration velocity, simulating creep conditions effectively. The model accurately predicts recrystallization kinetics and microstructural evolution, exhibiting a strong correlation with experimental results, with an error of approximately 5%. This research provides a robust and efficient approach for predicting creep behavior in high-temperature applications, vital for optimizing material selection and predicting component lifespan in industries. The methodology offers a significant advancement in understanding and predicting DRX-driven creep behavior.This research was funded by the Research Council of Shiraz University, grant number 99-GR-ENG 15. The APC was funded by Brunel University of London
Immanuel Kant
No full textZusammenfassung: Da Žižek die Tradition des Deutschen Idealismus als zentralen Bezugspunkt betrachtet, spielen die Werke Kants eine entscheidende Rolle in seiner philosophischen Entwicklung. So sieht er in Kants Philosophie Vorwegnahmen zentraler Konzepte von Freud und Lacan, wie das fordernde „Über-Ich“ oder die radikale Negativität des „gespaltenen Subjekts“. Dennoch kritisiert Žižek, dass Kant die radikalen Konsequenzen seiner eigenen Überlegungen nicht vollständig erkannt oder formuliert hat. Dies zeigt sich in Žižeks Auseinandersetzung mit Kants drei Kritiken, wobei er sich in deren Rezeption primär auf Fragen der Subjektivität, des moralischen Gesetzes und auf das Erhabene konzentriert. (Aus dem Englischen übersetzt von Tobias Schimpfle. [Translated from English by Tobias Schimpfle.])
Sulayman Najm Khalaf, 1946–2023: A Pioneering Anthropologist of the Gulf and Syria
Get PDFThis article celebrates the life and scholarship of Sulayman Najm Khalaf (1946–2023), Syria’s first social anthropologist who made important contributions to the fields of Gulf and Syrian Studies, as well as Intangible Heritage. It traces his life’s journey from a Bedouin upbringing in the Euphrates Valley to a pioneering scholar of Syria and the Gulf. It highlights his contributions to the study of society and tribal politics in rural Syria and the impact of oil wealth on the Gulf Arab states –– on Gulf citizens, cities, heritage, identity –– and the lives of migrant labourers who work there. It emphasises his ethnographic rigour and theoretical innovation in the study of social change and modernity. It concludes by assessing his enduring legacy for Middle Eastern anthropology and the academic communities he cultivated
Study of ignition and combustion processes of methane and ammonia using both conventional and advanced ignition methods
No full textThis thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonThe ignition system plays a major role in igniting the air-fuel mixture in internal combustion
engines (IC) to produce maximum power and least emission possible. Excessive
ignition retard can lead to higher Hydrocarbon (HC) emission and too much advance can
lead to higher Oxides of Nitrogen (NOx) emission. The conventional ignition system is
energy intensive, prone to electrode erosion, limited to a single ignition point and less effective
for lean combustion of fuels with lower ignitability. Therefore, innovative ignition
systems must be explored and developed to support ultra-lean burn combustion of future
low carbon and zero carbon fuels. Certain sectors of transport like the shipping and
power generation, ammonia has a significant potential for decarbonization. Ammonia being
the fuel with lower burning velocity and higher ignition energy than most fossil fuels,
successfully igniting ammonia for complete combustion is necessary in the adoption of
ammonia as a zero carbon fuel in IC engines. Hence, in the present work the combustion
characteristics of ammonia were studied in addition to methane.
The first phase of the current work involves setting up a new experimental test rig including
a pressurized constant volume chamber, multiple-fuel intake system, ignition system,
control system and data acquisition system. The chamber of 3.5 litre capacity was designed
by the author and manufactured by an external company. The second phase
focused on the design of a new Barrier Discharge Ignition plug with different ceramic
materials and dimensions. High speed flame imaging with Schlieren imaging system was
used to capture the development of flame from the time of ignition. Methane and ammonia
air mixtures were tested in the constant volume chamber to compare the energy
requirement and the flame development. The ignition systems evaluated include Transistorized
Coil Ignition (TCI) with J-hook spark plug, Nanosecond Repetitively Pulsed
Discharge (NRPD) with J-hook spark plug and Barrier Discharge Ignition (BDI) plug.
The methane-air mixtures were tested at 1 bar (gauge) initial pressure and a temperature
of 20OC using all the ignition systems. The minimum ignition energy required to ignite
the methane air mixtures is 45 mJ, 30 mJ and 6 mJ for TCI, NRPD with J-Hook and
NRPD with BDI respectively at all lambda values. The spectroscopic studies of methane
air mixtures showed more oxygen and hydrogen atoms near the spark plug that resulted
in successful ignition and subsequent flame propagation. Lesser atoms near the spark
plug tip has resulted in partial burning and incomplete combustion confirmed by the
corresponding pressure traces. Unlike methane-air mixtures, the ammonia air mixtures could not ignite at ambient temperature
and required pre-heating of the chamber in steps of 50OC from ambient upto
200OC. The Barrier Discharge Ignition was able to achieve reliable ignition of the stoichiometric
ammonia air mixtures at and above 50 OC thanks to its distributed streamers.
Both the Transistorized Coil Ignition and Nanosecond Repetitively Pulsed Discharge
with J-Hook spark plug was capable of igniting the ammonia from 150 OC. The minimum
amount of ignition energy required to ignite the ammonia air mixtures is 118 mJ,
400 mJ, and 64 mJ for TCI, NRPD with J-hook spark plug and NRPD with BDI plug
respectively.
The Barrier Discharge Ignition system was able to ignite the methane air mixtures reliably
up to 1.8 lambda and the ammonia air mixtures up to 1.4 lambda. The breakdown voltage
for the BDI and the J-hook spark plug is 22 kV and 14 kV respectively influenced by the
spark plug geometry as well as the air-fuel mixture resistance in the chamber. Among all
the ignition systems tested with ammonia and methane air mixtures, BDI outperformed
in terms of faster flame propagation and better heat release rate
Country-level drivers of biodiversity disclosures: international evidence and policy implications
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Data available on request from the authors.Supplemental Material:
Supplemental data for this article can be accessed online at https://doi.org/10.1080/01559982.2025.2468992.Biodiversity loss and species extinction represent urgent global policy issues, exerting substantial pressure on organisations to address these challenges. Multinational Enterprises (MNEs) are increasingly incorporating biodiversity protection efforts into their reporting frameworks. Despite this trend, the external governance mechanisms driving such disclosures remain underexplored. This study examines the influence of a country's legal system, level of corruption, and cultural background on MNEs’ biodiversity and species extinction disclosures from an international perspective. Utilising a sample of the top 200 Fortune Global MNEs over a five-year period and drawing on institutional and legitimacy theories, we find that MNEs headquartered in countries with weaker legal systems and higher corruption levels provide more extensive biodiversity disclosures. Additionally, national culture is identified as a critical determinant of biodiversity disclosure. Our analysis also reveals that macroeconomic uncertainty significantly moderates these disclosures. Furthermore, the introduction of the United Nations Sustainable Development Goals in 2015 is shown to impact disclosure practices. These findings challenge the prevailing assumption that MNEs in stronger institutional environments are more responsive to external pressures. This study provides the first empirical evidence that external governance mechanisms and macroeconomic factors significantly influence biodiversity disclosures. The results, robust across alternative measures and sub-sample analyses, highlight the necessity of robust legal systems, anti-corruption initiatives, cultural sensitivity, and economic stability in achieving global biodiversity targets. These insights bear significant implications for regulators and policymakers, emphasising the need for comprehensive institutional support to enhance biodiversity protection efforts
Corticospinal excitability is facilitated during coordinative action observation and motor imagery
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The datasets generated during and/or analyzed during the current study are publicly available on the Open Science Framework and can be accessed using the following web link: https://osf.io/qs2ym/.A preprint of the article is available on bioRxiv at doi URL: https://doi.org/10.1101/2024.12.11.627678. It has not been certified by peer review.Combined action observation and motor imagery (AOMI) facilitates corticospinal excitability (CSE). This study used single-pulse transcranial magnetic stimulation (TMS) to explore changes in CSE for coordinative AOMI, where the observed and imagined actions are related but not identical, for a single-leg sit-to-stand (SL-STS) movement. Twenty-one healthy adults completed two testing sessions including baseline (BL), action observation (AO), and motor imagery (MI) control conditions, and three experimental conditions where they observed a slow-paced SL-STS while simultaneously imagining a slow- (AOMIHICO), medium- (AOMIMOCO), or fast-paced (AOMILOCO) SL-STS. A TMS pulse was delivered to the right leg representation of the left primary motor cortex at three stimulation timepoints aligned with peak electromyography (EMG) activity of the knee extensor muscle group for the fast- (T1), medium- (T2), and slow-paced (T3) SL-STS during each condition. Motor evoked potential (MEP) amplitudes were recorded from the knee extensor muscle group as a marker of CSE for all stimulation timepoints and conditions. A main effect for experimental condition was reported for all stimulation timepoints. MEP amplitudes were significantly greater for AOMIHICO at T1 and T3, and AOMIMOCO and AOMILOCO at all stimulation timepoints, when compared with control conditions. This study provides neurophysiological evidence supporting the use of coordinative AOMI.The authors declare that no financial support was received for the research and/or publication of this article
Synergetic regulation of hydration and carbonation of reactive MgO cement by amino acids
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Data will be made available on request.This study investigates the role of L-aspartic (L-Asp) in regulating the crystallisation of hydrated magnesium carbonates (HMCs) in carbonation-cured reactive MgO (RM). The effects of L-Asp on hydration kinetics, bulk density, compressive strength, phase composition, carbon sequestration, microstructure and morphology of RM composites were examined to understand its influence on the coupled hydration and carbonation processes. It has been found that L-Asp delays the precipitation of Mg2+ and OH−, promoting the formation and stabilisation of the metastable nesquehonite (MgCO₃·3H₂O) polymorph. Carbonated composites incorporating L-Asp demonstrate a higher carbonation degree and enhanced stability compared to those without L-Asp. Notably, samples containing 0.2 M L-Asp sequestrated 46.7 % more CO2 than those without amino acids. Additionally, amino acids lead to denser carbonation products with modified morphology, significantly enhancing carbonation efficiency and compressive strength. This study unveils the synergetic mechanism by which L-Asp influences hydration and carbonation in MgO-based binders, contributing to their enhanced performance.The authors would like to thank the financial support from UKRI under grant EP/X04145X/1 (i.e., the CSTO2NE project) and the European Commission under grant 893469 (i.e. the NEASCMs project). The first author would also like to thank Zhongyuan University of Technology for providing a partial PhD scholarship to him to proceed with this study at Brunel University London
Leveraging multiomic approaches to elucidate mechanisms of heterogeneity in Alzheimer’s disease: neuropsychiatric symptoms, co-pathologies, and sex differences
Get PDFAt end of the list of authors: Neuropsychiatric Syndromes Professional Interest Area MultiomicsWork Group, Alzheimer’s Association, International Society to Advance Alzheimer’s Research and Treatment, Chicago, Illinois, USASupporting Information is available online at: https://alz-journals.onlinelibrary.wiley.com/doi/full/10.1002/alz.70549#support-information-section .The heterogeneity of Alzheimer's disease (AD) is multi-dimensional, encompassing clinical features such as neuropsychiatric symptoms (NPS), rate of progression, age of onset, comorbidities, and neuropathological features such as co-pathologies, and represents the diverse outcomes of manifold genetic and environmental risk determinants. These diverse features of AD also vary significantly between sexes and across ancestral backgrounds, but the specific variations and causal mechanisms are not well understood. Recent technological advances, particularly single-cell and spatial omics, have provided new tools to dissect the molecular underpinnings of AD heterogeneity and its multifactorial nature. This perspective review highlights molecular differences, general and sex-specific, that contribute to the heterogeneity of AD in aspects such as NPS, co-pathology prevalence, and general disease trajectories. We further examined the potential for multiomic approaches to direct future translational studies aimed at the development of precision medicine strategies for the treatment of AD in all its diverse forms.National Institutes of Health/National Institute on Aging. Grant Numbers: R01 AG057522, RF1 AG077695, R00AG078503, R00AG075238, R01AG067015;
National Institute of Neurological Disorders & Stroke. Grant Numbers: RF1-NS113548-01A1, ZIANS003154;
National Institute on Alcohol Abuse and Alcoholism. Grant Number: 2U10AA008401;
Cure Alzheimer's Fund;
The State of São Paulo Research Foundation. Grant Number: 2015/10109-5;
Alzheimer's Association. Grant Numbers: AARG-24-1027303, 22-AAIIA-953269, AARF-22-967171
More transparency on regional human rights courts? What we (still) need to know to understand and access regional human rights justice
Get PDFRegional human rights courts operate in a way that is only partially open to scrutiny from the outside. Rules of procedure are available to read, but researchers and practitioners know very little about what happens inside the courtroom and how judges make their final deliberations. This article focuses on the African Court of Human and Peoples’ Rights, the European Court of Human Rights, and the Inter-American Court of Human Rights and explores three particular and overlooked aspects of their functioning: the role of the secretariats, third-party submissions, and the contribution of individual judges in courts’ deliberations. Comparing best practices and lessons learned from the three systems, the article recommends some measures to improve transparency from the perspective of potential applicants and researchers trying to understand the adjudication of regional human rights systems
A Multi-Dimensional E-Participation Model to Boost Public Confidence in Democracy in Rural Uganda: Participatory Approach
Get PDFElectronic participation (e-participation) is an essential e-government instrument used by government across the world to support democratic decision-making processes. Despite its usefulness, e-participation initiatives face challenges, emerging predominantly from the limited involvement of the actual users in design and deployment of e-participation models and systems. Limited users’ involvement restricts guidance on which model requirements and dimension would be suitable for promoting democracy in specific settings through use of eparticipation initiatives. Consequently, the users’ needs suitable for specific context is inadequately addressed in most existing models and e-participation initiatives. This leads to the public losing interest in using e-participation initiatives to achieve democracy. This paper proposes a new multidimensional model derived from users’ perspectives on model requirements that boost the public's confidence in using e-participation to achieve democracy. Two participatory workshops involving 23 participants from local government leaders and ordinary rural citizens from two parishes in Isingiro district Uganda were deployed to generate insights and gather model requirements used to develop the model. The study provides a model consisting of seven dimensions including 1) socio-technical contextual discovery, 2) actors, 3) technology, 4) levels of digital device usage, 5) strategies, 6) e-participation system requirements and 7) expected outcomes. The model provides guidance on how e-participation initiatives can be designed so that they capture public's priority needs tailored to their context to boost the public's confidence in e-participation.UK government through the Commonwealth Scholarships Commission in the UK
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