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Propeller Design for Hydrogen-Electric Aircraft
Full text linkWith increasing interest in hydrogen aviation over the past several years, Proton Exchange Membrane Fuel Cell (PEMFC) powertrains have become a leading candidate for propelling short to medium haul flights. PEMFCs facilitate an electro-chemical reaction between hydrogen and oxygen to power electric motor driven-propellers. Existing powertrain modeling workflows typically employ generic look-up surfaces called propeller maps for propulsor performance. These are often unrepresentative of real blade geometries and assume equal performance across propeller diameters and rotation rates. In this study, Blade Element Momentum Theory (BEMT) is coupled to a PEMFC powertrain model developed in OpenConcept to afford an improvement in simulation fidelity and -- critically -- overall performance of the powertrain. A regional aircraft (DHC-8) with a PEMFC powertrain was modeled with a default propeller map from OpenConcept to serve as a performance baseline. Subsequently, BEMT was used to develop a propeller map where the geometry of the propeller and its performance at prescribed flight conditions are known. This map was evaluated against the baseline with and without a safety margin penalty and showed that powertrain optimization is sensitive to propeller design: an increase in weight margin of 2 tonnes combined with reductions in Balance of Plant and fuel masses of 1.2 tonnes and 89 kg were observed. Additional fidelity for thermal, structural and acoustic models unlocked by BEMT are presented. An extension of the modeling to incorporate aeroacoustic analysis is included to demonstrate the far-reaching impacts of including low-order propeller simulation into the design framework
Rational points in a family of conics over <sub>2</sub>(<i>t</i>)
Full text linkSerre famously showed that almost all plane conics over (Formula presented.) have no rational point. We investigate versions of this over global function fields, focusing on a specific family of conics over (Formula presented.) which illustrates new behavior. We obtain an asymptotic formula using harmonic analysis, which requires a Tauberian theorem over function fields for Dirichlet series with branch point singularities.</p
A Comparative Analysis of FLE Wellness Benefits and Customer Responsiveness:A Social Exchange Theory Perspective
Full text linkGiven the importance of frontline employees (FLEs) for organizations and consumers, it is important to motivate them to achieve optimal performance. One way to motivate FLEs is through employer-provided wellness benefits, which might increase FLEs’ responsiveness to customer needs. Building on social exchange theory, this research simultaneously examines five different wellness benefits to identify factors that can enhance FLEs’ feelings of being valued and an induced sense of indebtedness, which in turn can have downstream effects on customer responsiveness. The results of five studies, including a pilot study, preliminary sales study, field studies, and an internal meta-analysis, demonstrate how food and social benefits exert the strongest effects, with food yielding stronger direct effects on customer responsiveness and both showing indirect effects through value and indebtedness feelings. The next strongest effects are from mindfulness benefits. Physical and health wellness benefits exert the weakest downstream consequences. Importantly, if FLEs are in a supportive work environment, the effects of food and social benefits are enhanced. Conversely, job stressors and motivational constructs do not significantly impact the effects of employer-provided wellness benefits. By adopting the provided recommendations, retailers and service providers can institute effective and optimal wellness programs to enhance their FLEs’ customer-facing behaviors
Afraid to Be Vulnerable?:Women, Leadership, and the Constructive Role of Vulnerability for Organizations
Full text linkThis article draws attention to the value, for leaders and organizations, of recognizing and working with vulnerability. In the opening, we mobilize the “writing differently” approach. Specifically, we present a poem co-written by the authors to sensitize ourselves and readers to the importance of acknowledging and embracing vulnerability, which we view as an existential condition and an inherent aspect of the leadership experience. We then discuss insights from our qualitative study, based on photo-elicitation interviews with thirty-five senior women leaders in Poland, highlighting the role of vulnerability in their experiences and practices. Our research suggests that, in response to organizational norms that often discourage the expression of emotions and the display of vulnerability, especially by leaders, women leaders consciously manage and even suppress their sense of vulnerability. We argue that embracing vulnerability can bring much more positive outcomes for individuals and organizations. The article concludes with practice-oriented implications for leaders, organizations, and researchers, promoting a more sustainable and integrated approach to vulnerability in professional life
The dynamic effects of becoming disabled on work, wages and wellbeing in the UK from 1991 to 2018
Full text linkOver recent decades it has consistently been shown that disabled adults in the UK fare worse in the labour market and have lower levels of wellbeing than non-disabled adults. However, this is in part due to the selection into dis-ability of those with existing socio-economic disadvantages. In this article, we use panel data from the combined British Household Panel Survey and Understanding Society, covering the 27-years from 1991 to 2018, to distinguish between the effect of selection, the effect of dis-ability onset and the effect of dis-ability duration on a range of labour market and wellbeing outcomes. We show that there is important selection both into dis-ability and into longer experience of dis-ability on the basis of observable characteristics. We also show the importance of controlling for time-invariant unobservable individual characteristics that similarly affect selection into dis-ability and duration of dis-ability. Even after controlling for both forms of selection we find significant negative effects of dis-ability onset and duration, and offer policy solutions to address them
Open Strategy as Institutional Work
Full text linkPurposeThis article positions institutional work as a central construct in open strategy research. While open strategy is widely celebrated for fostering transparency and inclusion, its potential as a mechanism for field-level institutional change remains underexplored. The study examines how managed openness enabled UK universities to perform institutional work that reshaped research culture and institutional logics in response to evolving field expectations around equality, diversity, and transparency.Design/methodology/approachDrawing on 17 in-depth interviews with senior leaders and 25 documentary sources from the N8 group of UK research-intensive universities, the study applies the Gioia methodology and critical discourse analysis to trace how open strategy practices were mobilized to enact institutional work. The analysis identifies three interrelated processes – motivating, signalling, and enacting – through which openness was purposefully managed to facilitate cultural and institutional transformation.FindingsOpen strategy practices operated as discursive, symbolic, and material mechanisms of institutional work. By framing change imperatives, demonstrating commitment, and empowering participation, leaders used managed openness to align organizational practices with emergent field-level logics. These processes culminated in research culture action plans that institutionalized new norms of transparency and inclusion across the N8 universities.Originality/valueThe article advances open strategy theory by establishing institutional work as a powerful lens for understanding how openness extends beyond organizational boundaries to orchestrate field-level change. It also introduces institutional critique as a precursor to institutional work, highlighting the role of elite actors and discursive legitimation in shaping openness as a strategic and institutional practice.<br/
Enhanching Assessment as Learning:The Influence of Language Assessment Literacy on Indonesian EFL Students’ Writing
Full text linkThis study examines the impact of enhancing Language Assessment Literacy (LAL) on Indonesian EFL students’ writing development through Assessment as Learning (AaL) practices. Unlike most research that emphasizes teacher-focused LAL, this study shifts attention to learners, exploring how assessment knowledge, particularly through rubrics, can promote metacognitive awareness, autonomy, and improved writing outcomes. A mixed-methods design was employed with 84 senior high school students randomly assigned to experimental and control groups. Results showed no significant differences between groups prior to the intervention. However, post-test scores indicated a significant advantage for the experimental group (M = 16.69) compared to the control group (M = 8.91), with a large effect size (η² = .82), confirming the effectiveness of LAL-based pedagogy. Qualitative interview data revealed that students’ attitudes toward LAL strongly shaped its classroom integration. Although learners initially reported limited experience, low confidence, and concerns about the reliability of peer assessment, they ultimately expressed positive perceptions of LAL, highlighting its role in clarifying writing expectations, supporting reflection, and fostering learner autonomy. These findings suggest that embedding LAL in EFL writing instruction can transform assessment into a learner-centered process that enhances both writing performance and self-regulated learning. Pedagogically, the study underscores the importance of scaffolding and supportive implementation of student-centered assessment practices. However, the study is limited by its short intervention period and context-specific sample. Future research should adopt longitudinal designs, involve diverse contexts, and explore digital tools to support sustainable LAL integration
Effect of the [Fe(salen)]<sub>2</sub>-μ-oxo Catalyst Electronic Structure on Reductive Hydroamination
Full text linkSalen 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
Firm Positionality and Strategic Communication:Analyzing the Value of Informativeness for Managers
Full text linkThis study explored the moderating effects of price informativeness on the relationship between brand value and firm positionality. We argued that major effects for price informativeness are not confined to its direct effects on a firm’s market position or value, but in its moderating effects on brand-firm relationship. At the same time, the analysis confirmed that price informativeness can negatively moderate brand value’s influence on firm positionality. This study has significant implications for firms to strategically position and implement their communication strategies in a better way as to rapidly respond to fluctuations in the firm’s positionality
Quantile-adaptive probabilistic forecast combining
Full text linkCombining forecasts of cumulative probability distributions (CDFs) allows aggregation of the available information to improve accuracy. The linear opinion pool is commonly used, but it can yield overdispersed distributional forecasts. An alternative, leading to lower dispersion, is to average the quantiles of the CDF, which can be viewed as horizontal CDF averaging, with the averaging of probabilities in the linear opinion pool viewed as vertical averaging. Empirical results show that horizontal and vertical averaging can each be preferable for different parts of the CDF. For example, one method might be better for tail quantiles, while the other is better for central quantiles. To address this, we develop a method that transitions between vertical and horizontal averaging across the CDF. It relates to angular averaging, which is a recent proposal that performs aggregation along lines at an angle. Our new method averages along lines with slopes that smoothly transition across the CDF. The method is quantile-adaptive in the sense that the slopes of the lines vary across the quantiles, or equivalently, across the probabilities. We set the lines to emanate from a small number of fixed points, which are the parameters of the method. Viewing the lines as rays, we term the method radial averaging. Our theoretical results show that the method has the versatility to generate CDF forecasts that are sharper than horizontal averaging, and less sharp than vertical averaging. Our empirical results provide support for the new approach
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