The present work focuses on highlighting bimolecular reactions in the NH₃ system involving HO₂, an important radical at intermediate combustion temperatures. The reaction mechanism generator (RMG) tool was used to identify potentially significant reactions, and the automated rate calculator (ARC) tool was used to automatically compute rate coefficients at the ΛCCSD(T)/aug-cc-pVTZ-F12//B2PLYP-D3/aug-cc-pVTZ level of theory. Several reactions explored in this work, such as N + HO₂ ⇌ NH + O₂, NH + HO₂ ⇌ NH₂ + O₂, NNH + HO₂ ⇌ N₂H₂ + O₂, and HNO₂ + HO₂ ⇌ NO₂ + H₂O₂, have not been thoroughly investigated in the existing literature. In particular, the reaction HNO + HO₂ ⇌ HNOH + O₂, though known, lacks a precise rate coefficient in recent chemical kinetic models for ammonia. This study provides computed rate coefficients for 10 hydrogen abstraction and disproportionation reactions involving HO₂ in the NH₃ system. The reaction rate coefficients computed here may improve future low- and intermediate-temperature oxidation models of NH₃.

The control of dynamic stall associated with wind turbine and helicopter blades, fixed-wings, flapping wings, as well as alternating flow separation and attachment produced by cyclical control inputs, is reviewed. Different airfoil and wing stall types are described, control metrics are identified, and the generality of harmonic pitch oscillations is clarified. A major emphasis is placed on nominally incompressible flows, and includes dynamic stall management, passive control devices, steady and unsteady active control techniques, scheduled control, iterative learning control, closed-loop control, flapping-wing flight, and computational predictions. Large control authority is attained by suppressing and inducing dynamic stall by means of low-frequency leading-edge slot blowing on thick airfoils, appropriate for horizontal axis wind turbine blade load control. High-frequency unsteady dynamic stall control is effective because its resultant stall-controlling leading-edge vortices are generated at more than an order-of-magnitude faster than the dynamic stall vortices. Alternating flow separation and attachment can be exploited to achieve secondary objectives, like the control of trailing vortices and enhanced turbulent mixing. Simple closed-loop control is achieved by adaptation of stall warning methods, and a feedforward/feedback control architecture is shown to be expedient and practical for gust alleviation on small vehicles. On flapping wing flyers, the roles of dynamic stall and its control are different for propulsive flight and hovering flight. For propulsive flight, active flow control can potentially be used to increase propulsive efficiency. For hovering, a relationship appears to exist between Strouhal numbers associated with insect flight, leading-edge forcing on flat-plate airfoils and low aspect-ratio flat wings, and vortex shedding. Accurate numerical predictions of dynamic stall control, namely, code validations against experimental data, have not been adequately performed, and dedicated experimental test cases for this purpose are proposed. Under subsonic compressible conditions, dynamic stall is driven by shock-induced separation, where passive leading-edge modifications with vortex generators, discrete wall-normal jet or micro-jet blowing, and dielectric barrier discharge actuation all show significant control potential.

The desalination fuel cell (DFC) represents a novel electrochemical technology that simultaneously desalinates water and generates electricity by coupling oxidation-reduction reactions. This study introduces a theoretical framework to support experimental findings and further elucidates DFC performance mechanisms. Unlike traditional electrodialysis (ED), where an externally applied electric potential drives desalination, the DFC employs redox half-reactions to achieve ion separation and energy conversion. The proposed H2-O2 DFC system, previously tested only experimentally, is examined here theoretically for the first time. The system features a desalination channel, bordered by anion and cation exchange membranes (AEM and CEM), with reacting catholyte and anolyte streams driving the desalination process. To evaluate cell performance, the model incorporates electrolyte composition variations, ionic interactions, resistances, and electrode kinetics. Mass transport is governed by the Nernst-Planck equation under the electroneutrality assumption, while electrochemical kinetics account for both activation and concentration overpotentials. The results provide insights into the interplay between desalination efficiency, ionic fluxes, and electrochemical processes, advancing the understanding of DFC operation and optimization strategies.

Considering the climate crisis, global environmental awareness, and the pursuit of sustainable architecture, various methodologies and global standards have been developed to assess and reduce the environmental impact of construction projects. Green Building Codes (GBCs) and rating systems have been implemented worldwide to support green building practices based on the use of simulation models to evaluate energy consumption, such as the ENERGYui and others to rate buildings based on their simulated energy performance. Israel has also established green building standards, such as SI 5281, which provide practical tools for architects to promote the use of green building methods. However, several studies have cast doubt on the actual measured performance of certified buildings. This study evaluates the effectiveness of the Israeli green building certification process (SI 5281/SI 5282) through a comparison between simulation-based ratings with measured post-occupancy electricity consumption. Through four case studies, the research identifies discrepancies, explores their causes, and proposes refinements to certification assumptions and evaluation methods. The research is intended to enhance the effectiveness of assessment tools in architectural design and contribute to more precise and sustainable green building practices. This study identifies significant gaps between simulated and actual energy consumption in Israeli green buildings, highlighting that, within this framework, educational buildings tend to exceed predicted usage, while residential buildings often consume less, thereby exposing limitations in current simulation assumptions and standard evaluation criteria.

The rising levels of carbon dioxide (CO2) in the atmosphere significantly contribute to climate change, highlighting the need for effective CO2 mitigation strategies. While capturing and storing CO2 is important, converting it into useful products offers additional environmental and economic benefits. One promising method is the reverse water gas shift (RWGS) reaction, which transforms CO2 into carbon monoxide (CO). Membrane reactors (MR), which integrate selective membranes with equilibrium limited chemical reactions, have the potential to intensify processes based on the RWGS reaction. In such reactors, by-products like water are removed in-situ from the reaction zone, effectively shifting the reaction equilibrium to favor higher CO2 conversion. This study develops a comprehensive multi-scale mathematical model for RWGS membrane reactors. We integrate the microscale permeance model (for LTA-4A membrane) with the RWGS MR unit scale and the system’s scale models. The effectiveness of applying sweep gas has been suggested, and the optimal H2 perm-selectivity is found in the range from 30 to 50. A detailed membrane permeance model for LTA-4A membranes is integrated in the MR model to assess how species permeance changes with varying reactor conditions. We propose a sweep recycle configuration and compare it with the conventional sweeping configuration commonly assumed in most literature. A thermal efficiency analysis is conducted to evaluate the proposed recycling configuration, providing insights into the practical feasibility of membrane reactors for CO2 utilization.

ZnZrO_x solid solution catalysts have gained considerable attention for their effectiveness in CO₂ hydrogenation and the conversion of methanol to C²⁺ products. However, their performance in high-temperature hydrogenation of CO₂ to methanol needs enhancement. In this study, we present a surface engineering approach for these catalysts by thermally treating a ZnZr hydroxide precursor in a reducing atmosphere (H₂/Ar). This method promoted the migration of Zn from the bulk of ZrO₂ to the surface layer, leading to the formation of abundant asymmetric oxygen vacancy (Zn–O_v–Zr) sites. Consequently, the 11.5ZnZr-500H₂/Ar catalyst (treated in H₂/Ar) exhibited a methanol selectivity of 83.0% at 325 °C, which is significantly higher than the 54% selectivity of 11.5ZnZr-500Air (treated in air) at the same temperature and comparable to the 85.1% selectivity of 11.5ZnZr-500Air at 275 °C. By selectively removing Zn at various levels through acid treatment of the catalysts, we have discovered an almost linear correlation between the concentration of asymmetric oxygen vacancies and the yield of methanol production. DRIFTS measurements and DFT calculations demonstrate that these active sites enhance the CO₂ activation and conversion of formate intermediates during the methanol synthesis process. This study is the first to identify the catalytic function of the asymmetric Zn–O_v–Zr sites, paving the way for the subsequent production of C²⁺ products.

The coupling of fast pyrolysis with green catalysis offers a sustainable approach for transforming waste polypropylene (PP) plastic into valuable hydrogen and carbon materials. The intrinsic catalytic activities of biochar, Al₂O₃@biochar, Fe₃O₄@biochar, Fe₂AlO₄@biochar, and FeAl₂O₄@biochar are explored for upgrading the fast pyrolysis vapors of PP powder. The FeAl₂O₄@biochar catalyst with tetrahedral iron sites achieves an excellent hydrogen yield, equivalent to 86.25 H% in PP. The hydrogen yield from converting practical PP mask waste reaches 57.98 ± 1.96 mmol g_plastic^–1, more than 673.61 ± 7.00 mmol g_Fe^–1. The density functional theory (DFT) calculation indicates that a closer d-band center of FeAl₂O₄ is more favorable for C–H bond activation and that dehydrogenation of propylene as a model compound is the primary source of hydrogen production, more readily than C–C bond cleavage, and efficiently generates H₂.

The development of durable, non-platinum electrocatalysts for the hydrogen oxidation reaction (HOR) in alkaline media is a critical challenge in scaling high-efficiency anion-exchange membrane fuel cells (AEMFCs). Also, designing electrocatalysts exhibiting both high activity and structural stability is essential. In this study, we introduce a novel electrocatalyst composed of cerium oxide-decorated palladium nanoparticles supported on carbon (CeOx-Pd/C), synthesized via controlled surface reaction (CSR), to engineer nanostructures with well-defined CeOx–Pd interfaces and tunable Ce/Pd atomic ratios. The selective deposition of CeOx facilitates hydroxide ion spillover and the adsorption/transfer of oxygenated species to Pd, boosting HOR activity and durability. However, despite its promising catalytic properties, the degradation behavior under electrochemical conditions has not been extensively studied. To evaluate this, we employed identical location transmission electron microscopy (IL-TEM) combined with electrochemical accelerated stress testing (AST), to directly visualize nanoscale structural evolution before and after electrochemical cycling. The results reveal the bifunctional nature of CeOx nano-islands: exhibiting record-high HOR activity (51.5 mA/mg) along with promoting protective and degradation-resistant anchoring mechanisms. Also, comprehensive and advanced STEM-EDS and EELS analyses confirm dominant Ce⁴⁺ valence and the intimate Pd–CeOx contact. Particle size analysis and morphological mapping further demonstrate that CeOx nano-islands suppress nanoparticle migration, agglomeration, and structural deformation under electrochemical stress. Our findings establish a robust structure–function–degradation relationship, positioning CeOx–Pd/C as a solution for next-generation AEMFCs. This work not only offers mechanistic insight into catalyst degradation but also introduces an oxide-mediated design strategy for advancing bifunctional electrocatalyst technologies in alkaline energy systems.

Microbial rhodopsins are light-sensitive proteins vital to various phototrophic and sensory processes in microorganisms. Xanthorhodopsins, with their dual chromophore system involving retinal and carotenoids, have been predominantly studied in the extreme halophilic bacterium Salinibacter ruber and in the primitive thylakoid-less cyanobacterium Gloeobacter violaceus, where they facilitate light- driven outward proton pumping and enhanced light-harvesting. However, their distribution, binding specificity, and ecological significance in cyanobacteria remain poorly understood. Here we report widespread xanthorhodopsin genes in cyanobacterial genomes and characterize a protein from an Antarctic filamentous cyanobacterium that uniquely binds hydroxylated lutein. Through bioinformatics, spectroscopic, functional and structural assays analyses, we determine the properties and ecological role of this cyanobacterial xanthorhodopsin. Our findings highlight xanthorhodopsins’ role in modulating light-harvesting efficiency in cyanobacteria, particularly in extreme environments. The lutein binding and associated structural changes likely provide selective advantages for adapting to polar light conditions, contributing to cyanobacterial survival in harsh habitats.