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Effect of the [Fe(salen)]<sub>2</sub>-μ-oxo Catalyst Electronic Structure on Reductive Hydroamination
Get PDFSalen ligands are privileged scaffolds in transition metal catalysis due to their electronic tunability and capacity to stabilize diverse oxidation states. Herein, we report the synthesis and comparative study of three electronically differentiated [Fe(salen)]2(μ-oxo) complexes and their application in catalytic reductive hydroamination (HA) of nitroarenes with alkenes. A mechanistic framework involving iron-hydride intermediates and hydrogen atom transfer (HAT) was developed, revealing that modulation of the salen ligand electronics significantly impacts product distribution and catalytic efficiency. Systematic investigation of substrate LUMO energies and precatalyst UV–vis spectroscopy, cyclic voltammetry, along with DFT calculations on the key HAT step, was undertaken. Notably, the complex bearing para-CF3 substituents outperformed its analogues across a range of olefin partners. These findings underscore the critical role of ligand electronics in tuning HAT-based catalysis.</p
Performance-based reliability assessment of quay walls
Get PDFFunctional demands on quay walls are steadily rising with increases in both ship size and the frequency of port calls, requiring robust safety and performance assessment frameworks. Most existing studies on quay walls remain constrained by simplified analytical or numerical models, limited consideration of failure modes, insufficient model validation, and the absence of site-specific soil correlation, making it difficult to assess real structures under realistic loading conditions. This study presents a novel Cone Penetration Tests (CPT)-driven, performance-based reliability framework that samples directly from measured CPT distributions to preserve field consistent parameter relationships without requiring site-specific covariance matrices. The framework is demonstrated on a recently constructed, full-scale instrumented quay wall in the Port of Rotterdam. A two-dimensional finite element model with the Hardening Soil Small-strain (HSS) formulation is calibrated against construction-stage monitoring (wall deformations and anchor forces) and coupled to a probabilistic engine to evaluate multiple ultimate and serviceability limit states through an explicit failure tree. Results indicate that the structural failure of the wall governs the overall reliability of the quay wall, while wall deformation is the most variable response requiring close monitoring. Sensitivity analyses reveal that deeper dredging and higher surcharge loads markedly reduce reliability with wall structural failure governing and serviceability limit states showing the highest sensitivity to these hypothetical changes. The proposed approach provides a generalisable CPT-based methodology for reliability assessment of geotechnical structures based on site investigation data and monitoring data, supporting more informed, data-driven decision-making in design, and life-cycle management.</p
Precarious work:A critical review and a proposal for future research
Get PDFThis paper provides an interdisciplinary critical integrative review of research on precarious work. Based on a review of 311 records, we develop an integrated framework that brings together the antecedents, outcomes, and responses to precarious work found in the literature. We also explain the discrepancy between the ideas of key influential thinkers about the existence of political potential of precarity, and the lack of fieldwork evidence that would suggest that this potential is coming to fruition. We highlight that prevailing theorisations do not take appropriate account of the historico-cultural embeddedness, or the intersectional experiences, outcomes of, and responses to precarious work in different locations. We outline a pathway for future research, arguing for: 1) shifting the empirical focus of studies towards greater inclusion of members of currently under-represented geographical contexts, occupations and social groups, and towards appreciation of the different, context-specific forms, impacts, and responses to precarious work; 2) developing a nuanced understanding of the experiences and outcomes of precarious work as an intersectional phenomenon; 3) decolonising our thinking about precarious work through engagement in reflexivity about the assumptions underlying the extant knowledge. Finally, we put forward policy recommendations for addressing the prevalence and impacts of precarious work worldwide
Inelastic behaviour and algebraic characterisation of long cylindrical shells under combined compression and bending
Get PDFLong thin-walled cylindrical metallic shells, widely used in civil engineering infrastructures such as wind turbine towers and pipelines, exhibit complex structural behaviour under combined compression and bending. This complexity arises from interactions between geometric and material nonlinearities, particularly cross-sectional ovalisation under bending. Current design standards, including Eurocode 3 Part 1-6, lack comprehensive guidance for such loading scenarios. As part of the ongoing development of Eurocode 3 Part 1-6, this study investigates the inelastic performance of long cylindrical shells under combined bending and compression through a detailed finite element modelling program. A wide range of geometric parameters, including radius-to-thickness ratios, lengths, and load eccentricities were analysed to assess the influence of nonlinearities on structural response. Based on the modelled results, algebraic calculation methods are proposed to complement existing design rules, offering more accurate predictions for the buckling and ultimate strength of cylindrical shells under combined compression and bending
Fabrication and characterization of taste-masked core-shell nanofibre mats for dual drug delivery of antihypertensives in pediatrics
Get PDFDrug adherence in pediatrics can be challenging due to bitter drug taste, dysphagia and polypharmacy. With pediatric hypertension on the rise worldwide, this study investigated the use of electrospinning to create a novel taste-masked, fixed-dose combination of lisinopril dihydrate (LIS) and amlodipine besylate (AML) for paediatric use. Electrospun nanofibres of the antihypertensives were formulated as core–shell fibres with polyvinylpyrrolidone (PVP), and Eudragit® EPO (EEPO) by applying an electrical charge to a viscous mixture of the drugs, polymers and solvents. The drug loading, release kinetics, morphology, thermal analysis, physical and solid-state characterization of the fibre mats were evaluated. Taste-masking was investigated in vitro by electronic-tongue analysis. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses showed smooth, non-beaded core–shell fibres with diameters in the nanorange. Fourier transform infra-red (FTIR) spectroscopy and x-ray diffraction (XRD) studies confirmed the drugs were amorphously dispersed within the fibres and thermal analysis studies showed acceptable stability profile of the formulations. Both drugs were over 90 % released in 15 mins consistent with immediate release formulations. The e-tongue mean sensor response plot showed the nanofibre mats achieved a statistically significant enhanced taste-masking (p < 0.0001) compared to raw amlodipine which registered a high bitterness reading of 87 mV. This study therefore indicates that coaxial electrospinning may be used to produce a fixed-dose taste masked nanofibre mat of LIS and AML that can potentially be used to improve adherence in children.</p
Large Data Limits of Laplace Learning for Gaussian Measure Data in Infinite Dimensions
Get PDFLaplace learning is a semi-supervised method, a solution for finding missing labels from a partially labeled dataset utilizing the geometry given by the unlabeled data points. The method minimizes a Dirichlet energy defined on a (discrete) graph constructed from the full dataset. In finite dimensions the asymptotics in the large (unlabeled) data limit are well understood with convergence from the graph setting to a continuum Sobolev semi-norm weighted by the Lebesgue density of the data-generating measure. The lack of the Lebesgue measure on infinite-dimensional spaces requires rethinking the analysis if the data aren't finite-dimensional. In this paper we make a first step in this direction by analyzing the setting when the data are generated by a Gaussian measure on a Hilbert space and proving pointwise convergence of the graph Dirichlet energy
Convergence theory for two-level hybrid Schwarz preconditioners for high-frequency Helmholtz problems
Get PDFWe give a novel convergence theory for two-level hybrid Schwarz domain-decomposition (DD) methods for finite element discretizations of the high-frequency Helmholtz equation. This theory gives sufficient conditions for the preconditioned matrix to be close to the identity and covers DD subdomains of arbitrary size, arbitrary absorbing layers/boundary conditions on both the global and local Helmholtz problems, and coarse spaces not necessarily related to the subdomains. The assumptions on the coarse space are satisfied by the approximation spaces using problem-adapted basis functions that have been recently analyzed as coarse spaces for the Helmholtz equation, as well as all spaces in which the Galerkin solutions are known to be quasi-optimal via a Schatz-type argument. As an example, we apply this theory when the coarse space consists of piecewise polynomials; these are then the first rigorous convergence results about a two-level Schwarz preconditioner applied to the high-frequency Helmholtz equation with a coarse space that does not consist of problem-adapted basis functions.</p
The case against duty free tobacco sales:An analysis from Aotearoa (New Zealand)
Get PDFIntroduction: Duty-free sales of tobacco reduce the impact of excise tax increases, a measure many governments have introduced to reduce tobacco consumption and smoking prevalence. We investigated the excise tax revenue foregone in Aotearoa (New Zealand), a country once regarded as having progressive tobacco control policies.Methods: Using data tobacco companies are required to supply to the NZ Ministry of Health, we estimated the revenue from excise tax and the Goods and Services sales tax (GST) forgone by sales of duty-free tobacco since 2014, when duty-free allowances were reduced.Results: The number of cigarettes and volume of roll-your-own (RYO) tobacco released for sale decreased following changes to the duty-free allowance and declined sharply in 2020 and 2021, when the international border was closed as a Covid-19 pandemic measure. Since 2022, forgone excise revenue has risen steadily and, in 2024, had nearly reached pre-pandemic levels. In total, foregone revenue amounted to between NZ96 million between 2015 and 2024.Conclusion: Duty-free sales of tobacco products represent a government-sanctioned price discount that undermines Aotearoa’s Smokefree 2025 goal and its obligations as a Party to the Framework Convention on Tobacco Control
Managing Buyer-Supplier Exchange Under Change: Supply Chain Projects, Initiation, and the Contingent Role of Fairness in Trust
No full textThe Narration of Status in Far-Right Populist Foreign Policy:The United States of Trump 2.0
Get PDFThis paper focuses on how, during his second mandate, far-right leader Donald Trump tells a story of his nation as having been disrespected in the recent past by national elites and global ones, while the leader and their close circle have the mission to repair that status as part of United States foreign policy (i.e. respect for the status of the US). When narrating a better future, Trump travels to a remote national past to show the possibility of reinstating US stature in the international. While constructing that better future, Trump also starts to unfold a foreign policy story of success to cement the brighter future in a retrospective way given this future has purportedly been previously lived in a more remote national past. Relied on here is symbolic interactionist role theory, strategic narrative analysis and the notion of ‘heartland’ from populism scholarship; this paper also contributes to the study of narratives of roles and populism in the field of foreign policy analysis by engaging with the IR notion of ‘status’. Taking an interpretative analysis approach, this case study shows how far-right leaders like Trump can conceive and play the status or master role of their states in foreign policy via strategic narratives
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