Towards circularity in the wind industry: Optimal reverse supply network design under various policy scenarios

Wind energy is key to supply renewable energy. However, the increasing number of end-of-life wind turbines is still predominantly landfilled, while regulatory aspects such as waste shipment and landfilling rules hinder the development and scalable implementation of reverse supply networks. This work aims to understand how EU directives impact the structure and viability of circularity-enabling networks by investigating the optimal reverse supply network design for end-of-life wind turbine blades under different policy scenarios. Three policy scenarios were explored through a Mixed-Integer-Linear-Programming model: (i) ‘as-is’ (ii) ‘EU Proposal 2021/0367′, removing transboundary restrictions on waste shipments; (iii) ‘Landfilling Ban’ enforcing an EU-wide ban on landfilling composites. The optimal reverse supply networks with minimum costs were identified for each scenario, contextually determining location and sizing of recycling facilities and calculating landfilling quota and GHG emissions. The costs and emissions were minimum for the EU Proposal scenario, at 15,706,041€ and 2,081 tCO2e respectively. A sensitivity analysis on landfilling gate fees highlighted that they should be significantly increased to incentivise higher recycling rates and close material loops. This research is the first to evaluate the effects of policy initiatives on the shaping of optimised reverse supply chains through mathematical programming methods. The work contributes to the waste management literature by designing optimal circular supply chain networks for the management of waste from wind turbines decommissioning at the EU-level to improve sustainability of renewable energy installations

Characterisation of a continuous blender : impact of physical properties on mass holdup behaviour

Continuous blenders are a key unit operation in Continuous Direct Compaction, a route to solid oral dosage forms that is receiving significant interest. Mass holdup in these blenders is a crucial variable; understanding how it is influenced by material properties, equipment configuration and process settings is key. The present work evaluated a Gericke GCM-450 blender for range of outlet weir aperture geometries (angled or horizontal), material properties (pure components and blends) and process settings (throughput and impeller speed). Results show opposing mass holdup behaviour depending on weir choice, material density and flowability, likely linked to the propensity of the material to form an inclined powder surface that matches – or does not – the chosen weir geometry. The present work underscores the need for fundamental process phenomena understanding, especially when insight is sought for how blender performance varies across multiple dimensions (throughput, impeller speed, material properties) and discrete equipment choices (weir geometry)

Sparse time-varying parameter VECMs with an application to modeling electricity prices

In this paper we propose a time-varying parameter (TVP) vector error correction model (VECM) with heteroskedastic disturbances. We propose tools to carry out dynamic model specification in an automatic fashion. This involves using global–local priors and postprocessing the parameters to achieve truly sparse solutions. Depending on the respective set of coefficients, we achieve this by minimizing auxiliary loss functions. Our two-step approach limits overfitting and reduces parameter estimation uncertainty. We apply this framework to modeling European electricity prices. When considering daily electricity prices for different markets jointly, our model highlights the importance of explicitly addressing cointegration and nonlinearities. In a forecasting exercise focusing on hourly prices for Germany, our approach yields competitive metrics of predictive accuracy

Well-being of hospitality employees : a systematic literature review

The hospitality industry employees' well-being is relevant for practitioners and researchers alike. Academic interest in hospitality employee well-being (EWB) has been steadily rising. Yet, the unintended result has been a fragmentation of the field, with at least 42 different theories addressing issues of EWB in hospitality. This study adopts a systematic literature review approach to re-balance a fragmentation that can lead to myopia and assesses relevant literature on EWB in hospitality. The study identifies 122 articles in 19 relevant hospitality journals listed in Scopus utilising the PRISMA process and analyses them with the help of a framework derived from well-being reviews in corresponding fields, such as human resource management. The findings account for individual, group and organisational level stressors, resources and practices affecting EWB in hospitality, and they are subsequently related to the theoretical landscape in the field, suggesting future avenues for research

On repairable systems with time redundancy and operational constraints

For some repairable systems executing missions/tasks, a functional failure, i.e., a failure of a mission or task can occur not immediately after equipment failure but with some delay. This happens when a failure/defect is not repaired within some specified period of time. Alternatively, a functional failure can also occur when a new failure/defect happens relatively soon after the completion of the previous repair. In this paper, we present a new stochastic model that defines and describes the lifetimes of this kind of repairable systems with operational constraints. A new approach based on Laplace transforms is developed to study the reliability function and the mean time to failure for these systems. Furthermore, we consider the stochastic model when only a finite number of repairs are allowed and obtain relevant reliability indices for this case as well. Detailed numerical examples illustrate our findings

Heparin-azithromycin microparticles show anti-inflammatory effects and inhibit SARS-CoV-2 and bacterial pathogens associated to lung infections

Pulmonary infections are a leading cause of morbidity and mortality worldwide, a situation exacerbated by the COVID-19. Azithromycin (AZM) is used orally to treat pulmonary infections due to its ability to accumulate in lung tissues and immune cells after oral administration. Sulfated polysaccharides, such as heparin, are known to inhibit SARS-CoV-2 entry. This study presents a novel approach focused on developing a dry powder inhaler of AZM-loaded microparticles composed of either heparin or its derivatives. The microparticle formulations exhibited potent antiviral activity against SARS-CoV-2 (IC50 ≤ 95 nM) while retaining superior antibacterial efficacy against Streptococcus pneumoniae and Pseudomonas aeruginosa compared to free AZM (MIC ≤ 15 μg/mL). Importantly, at bactericidal concentrations, no cytotoxic effects were observed on mammalian cells, including Calu-3 cells and red blood cells. The formulations demonstrated effective alveolar aerodynamic deposition (MMAD ranging from 1 μm to 3 μm) with a Fine Particle Fraction below 5 µm close to 50 %. Adopting a conservative estimate of 20 mL for the pulmonary epithelial lining fluid volume in healthy adults, efficacious local concentrations of sulfated polysaccharides and AZM would be delivered to the lung using this multifaceted strategy which holds promise for the treatment of bacterial pulmonary infections associated with COVID-19

An ‘interface first’ bureaucracy : interface design, universal credit and the digital welfare state

The front-line of the welfare state is increasingly not a letter, phone call or face-to-face visit, but an online user-interface. This ‘interface first’ bureaucracy is a fundamental reshaping of social security administration, but the design and operation of these interfaces is poorly understood. Drawing on interview data from senior civil servants, welfare benefits advisors and claimants on the UK's flagship Universal Credit working-age benefit, this paper is a detailed analysis of the role played by interfaces in the modern welfare state. Providing examples from across the Universal Credit system, it sets out a five-fold typology of user-interface design elements in the social security context: (i) structuring data input, (ii) interaction architecture, (iii) operative controls, (iv) prompting and priming, and (v) integrations. The paper concludes by considering the implications of an ‘interface first’ welfare bureaucracy for future research

Impact of Li-Fi in 6G : challenges, applications, and prospects

With wireless communication technologies still developing, integrating light –fidelity (Li-Fi) with current and future cellular networks offers a viable way to improve data transfer performance. This paper examines Li-Fi’s performance in conjunction with 5G and speculates its possible use in upcoming 6G networks. The advantages, disadvantages and capabilities of Li-Fi, such as its reliance on the visible light spectrum for data transmission and its possible benefits, which include increased security and high data transfer rates, are also discussed. Further, we look at how Li-Fi and 5G networks can function together, followed by the impact of 6G on light fidelity. Using simulation-based assessments and empirical research, we compare Li-Fi and Wi-Fi performance to prove the reliability and security of Li-Fi

Hierarchically porous carbon foams coated with carbon nitride : insights into adsorbents for pre-combustion and post-combustion CO2 separation

Adsorption is fundamental to many industrial processes, including separation of carbon dioxide from other gases in pre- or post-combustion gas mixtures. Adsorbents should have high capacity and selectivity, which are both intimately linked with surface area, pore size distribution, and surface energy. Porous carbons are cheap and scalable adsorbents, but greater understanding of how their textural properties and surface chemistry affects their performance is needed. Here, we investigate the effect of nitrogen doping on CO2 adsorption. Microporous carbon foams with large surface area (>2500 m2 g−1) and pore volume (1.6 cm3 g−1) are synthesized, then coated with varying amounts of carbon nitride (up to 17 at% nitrogen) to achieve high CO2 uptake (25.5 mmol g−1) and selectivity (CO2:N2 = 21), whilst also giving insights into the relationship between structure and function. At low pressure (relevant to post-combustion capture), moderate carbon nitride loading leads to enhanced uptake and selectivity by combining large ultramicropore volume with the introduction of Lewis base sites, leading to high isosteric heat of adsorption. Higher carbon nitride loading further increases selectivity but lowers uptake by blocking micropores. Conversely, at high pressure (relevant to pre-combustion capture) the uncoated carbon foam displays superior uptake, because mesoporosity is the dominant factor in this regime, rather than the presence of ultramicropores. Finally, the samples displayed excellent regeneration under repeated adsorption–desorption cycles, and breakthrough curves were measured. These results underscore the delicate balance required for optimal material design when applying porous carbon adsorbents to CO2 separation processes. Moving forward, improved adsorbents will contribute to the proliferation of carbon capture and storage (CCS) and carbon capture and utilisation (CCU) technologies, ultimately contributing reduced anthropogenic CO2 emissions

Influencing others to prevent hospitality food waste : the reception of food waste messages by hospitality employees

Hospitality employees play a crucial role in food waste prevention, yet there is little understanding of how employees can influence the way food waste is thought about and dealt with within their workplace. To address this gap, we conducted semi-structured interviews with 23 UK hospitality actors, including frontline employees, managers and business owners to understand how they influence others, and have been influenced by others, to prevent food waste. We analyse the data through a sensemaking lens, which shows that food waste messages are received and made sense of instantly, or with delay due to exposure over time, or when the time is right. This reception process is active or passive, and congruent or incongruent, which has implications for whether food waste messages are understood as intended and the behavioural outcomes of the reception process. Developing a more comprehensive understanding of how food waste messages are received, understood and enacted has implications for food waste communications and how hospitality actors can influence the way food waste is thought about and dealt with within their workplace