Search Results (13,329)

In this study, bioceramic composites based on zirconia (ZrO₂) were synthesized and characterized in terms of mechanical properties. Two types of different-sized grains of zirconia powders were used to prepare the composites. A commercial zirconia micropowder (Tosoh) was used as a base for the composites modified with bioactive glass (BG), copper-doped bioactive glass (BGCu), and hexagonal boron nitride (hBN) with a sintering temperature of 1450 °C. The composites with the addition of hydroxyapatite, for which their sintering temperature was 1150 °C, were independently fabricated using a zirconia nanopowder prepared via co-precipitation and hydrothermal methods to achieve high densification and avoid hydroxyapatite decomposition. Mechanical performance of these composites was assessed with regard to biaxial flexural strength, Vickers hardness (HV), and fracture toughness (K_Ic). The reference 3Y-TZP material exhibited Vickers hardness (11.8 GPa) and fracture toughness (6.1 MPa∙m^1/2 values typical for dense tetragonal zirconia ceramics. The addition of all bioactive phases resulted in significant alterations in mechanical properties. Specifically, incorporating 20 wt.% HAp led to a threefold decrease in hardness and a 40% reduction in fracture toughness, while increasing the HAp content to 40 wt.% further reduced these properties. Nonetheless, the fracture toughness of these composites remained higher than that of pure hydroxyapatite materials. The incorporation of BG and BGCu reduced the hardness values by 45% and 30%, respectively, compared to 3Y-TZP. The most significant deterioration of the properties was observed for the 3Y-TZP-hBN composite. The 3Y-TZP–BGCu composite exhibited fracture toughness (5.9 MPa∙m^1/2) representing 95% of the toughness of pure zirconium dioxide, thereby showing the lowest weakness of all the other composites with bioactive additives. A slightly lower fracture toughness value (5.3 MPa∙m^1/2) was also observed in the composite with bioglass but lacking the copper additive. This factor, combined with a relatively small decrease in hardness in both cases, highlights high durability for implantology applications, thus marking the indicated materials the most promising among the composites studied. Full article

Co and Mo mono- and bimetallic catalysts supported on CNT-H-ZSM-5 composites were prepared and characterized using various techniques. The catalysts were evaluated for the conversion of sunflower oil (SO) into sustainable aviation fuel (SAF) hydrocarbons in the C₈–C₁₆ range. The effects of reduction temperature and metal loading were the main parameters investigated in this study. The catalyst reduced at 600 °C promoted the formation of Mo₂C species, resulting in high SO conversion (84%), complete deoxygenation, and enhanced isomerization within the C₈–C₁₆ fraction. Optimal metal loadings (2.5 wt% Co and 8 wt% Mo) and the bimetallic configuration led to superior performance compared with monometallic catalysts and physical mixtures, clearly highlighting a synergistic effect between Co and Mo species. In contrast, when waste cooking oil was used as feedstock, lower conversion and reduced selectivity toward SAF-range hydrocarbons were observed, which were attributed to the higher complexity and impurity content of this residue feedstock. Full article

In recent years, strong emphasis has been put on decarbonising the transport and mining sectors in an economically viable manner. To this end, ammonia is presented as a fuel, combining a high energy density (when compared to hydrogen) and zero carbon emissions. In this work, conversion of a mining haul truck engine is simulated for its use with an ammonia/diesel dual-fuel system at up to 70% Ammonia Energy Replacement (AER). The numerical setup is partially validated against engine performance data. The simulations suggest a reduction in CO${}_2$ emissions but an increase in N${}_2$O, which increases the carbon-equivalent emissions of the engine. Nevertheless, NO${}_{\mathrm{x}}$ emissions appear to be reduced, suggesting the use of post-treatment is required to deal with the issue of N${}_2$O. Cylinder temperature control is recommended for its reduction, as temperatures are lower when burning ammonia. On the other hand, the simulations suggest that ammonia slip increases with AER if diesel injection phasing is not optimised. Performance-wise, the engine develops a higher indicated mean effective pressure (IMEP) as AER increases, with a maximum at 40% AER, while combustion is delayed progressively into the engine cycle, as CAD50 values increase from −0.6 CAD ATDC at 0% AER to 20.1 CAD ATDC at 70% AER. Opportunities for further research are discussed, including more extensive experimental work to support or reject what is suggested by the simulations. Full article

The common root characteristic of CO₂ and air pollutants in the power industry, both derived from fossil fuel combustion, provides a natural basis for their synergistic emission reduction. However, existing studies suffer from the lack of a multi-pollutant synergistic evaluation system and an imperfect emission reduction technology database, which hinder their ability to support low-cost and high-efficiency emission reduction practices in the industry. Targeting the minimization of synergistic emission reduction costs and the maximization of emission reduction effects, this study integrated the process and economic parameters of 11 power generation technologies and 55 pollutant control technologies to establish a full-chain energy conservation and emission reduction technology database for the power industry, through literature research, industry surveys, and data mining. Based on the definition of pollution equivalent in the Environmental Protection Tax Law, we innovatively developed an air pollutant equivalent normalization evaluation method and constructed a two-dimensional coordinate system comprehensive evaluation system for CO₂ and air pollutants, enabling quantitative analysis and visual evaluation of the synergistic emission reduction effects of various technologies. The results show that new energy power generation technologies such as nuclear power and wind power, as well as O₂/CO₂ cycle combustion, ammonia-based desulfurization, and SNCR-SCR combined reduction technologies, exhibit excellent synergistic emission reduction performance for CO₂ and multiple pollutants. In contrast, some conventional pollutant control technologies, such as the limestone-gypsum method and traditional electrostatic precipitation, have significant CO₂ emission increase antagonistic effects. This study also completed the two-dimensional classification of 66 emission reduction technologies based on “emission reduction efficiency-economic cost”, identified application scenarios for different types of technologies, and proposed optimized paths for synergistic emission reduction adapted to the development of the power industry. The research findings fill the gap in quantitative standards for multi-pollutant synergistic emission reduction, provide theoretical support and detailed technical references for emission reduction technology selection and environmental policy formulation in the power industry, and help the industry achieve the dual development requirements of the “double carbon” goal and air quality improvement. Full article

The decarbonization of existing buildings remains a major challenge, particularly in contexts characterized by high energy demand and heating systems based on fossil fuels. While electrification is widely recognized as a key pathway, its direct application is often limited by building and operating conditions. This study investigates the potential of hybrid heating systems as transitional solutions through a large-scale numerical parametric simulation analysis based on representative models of the Italian residential building stock. The analysis explores the interaction between climatic conditions, system operation, and energy performance under standardized assumptions. The results reveal that hybrid systems achieve significant reductions in non-renewable primary energy (up to 39–44%) and CO₂ emissions (approximately 50–58%), primarily through the substitution of natural gas with electricity. Conversely, total primary energy may increase (approximately 2–26%) due to the contribution of renewable energy associated with heat pump operation. Operating cost savings are observed in the 25–40% range, with slight variation depending on climatic conditions. The effectiveness is not uniform, with maximum benefits in intermediate climate zones and reduced performance under more severe conditions. Overall, hybrid systems show stable and reliable performance across heterogeneous building configurations, supporting their role as robust mid-term transition technologies toward building decarbonization. Full article

The continuous increase in atmospheric CO₂ concentration exacerbates global climate change, making carbon reduction an urgent global priority. Carbonic anhydrase (CA), a highly efficient biocatalyst that converts CO₂ into bicarbonate, demonstrates significant potential for carbon capture and resource utilization. However, the stability and catalytic efficiency of native CA in industrial environments are limited, particularly its poor thermal tolerance under flue gas conditions and its sensitivity to impurities, hindering its direct large-scale application. This review systematically summarizes recent advances in modifying microbial CA through protein engineering (e.g., directed evolution, rational design) and immobilization techniques, which have markedly enhanced its thermal stability, adaptability, and reusability. Among these, the integration of machine learning with high-throughput experimentation has emerged as a transformative strategy for CA engineering. Furthermore, we outline CA-driven pathways for CO₂ conversion into high-value chemicals and bioenergy. Finally, future prospects are discussed, including interdisciplinary integration, computational modeling coupled with experimental validation, and comprehensive life-cycle and techno-economic assessments, to facilitate the scaled application of engineered microbial CA in carbon neutrality pathways. Collectively, this review highlights the critical role of engineered CA in bridging biocatalysis with industrial carbon management, offering a viable and sustainable pathway toward carbon neutrality. Full article

Aerobic exercise capacity, best quantified by maximal oxygen uptake (VO_2max), varies between individuals and is dependent on cardiac output (CO) and oxygen uptake in the periphery (a-vO₂ diff). Environmental stressors like hypoxia, microgravity, and heat negatively impact these parameters, thereby reducing aerobic exercise capacity. However, in response to acute and chronic exposures to these environments, compensatory processes serve to counteract reductions in VO_2max. In hypoxic environments, reduced oxygen partial pressure (PO₂) leads to hypoxic pulmonary vasoconstriction (HPV) and a diffusion limitation at the level of the lungs and skeletal muscle, resulting in a reduction in VO_2max. Microgravity environments reduce VO_2max through cardiac and skeletal muscle deconditioning, as well as reductions in plasma volume (PV), resulting in an increase in sympathetic nerve activity through baroreceptor-mediated pathways. In heat stress environments, increases in skin perfusion upon acute exposure hinder exercise performance, whereas compensatory PV expansion mitigates further decreases in VO_2max. As humans are increasingly exposed to austere environments and environmental extremes, it is critical to understand how these environments impact cardiovascular exercise physiology so that effective strategies and protocols ensuring proper aerobic functioning may be implemented. Full article

The performance and mechanism of heterogeneous catalytic reactions are fundamentally governed by the formation, stability, and reactivity of transient surface intermediates. These species—such as isocyanates, alkyl groups, carboxylates, formates, carbonates, alkoxy and acyl intermediates—often exist at low concentrations and with short lifetimes, making their identification challenging. This review summarizes the current knowledge on the formation, spectroscopic identification, and thermal behavior of these intermediates on metal single crystals, metal nanoparticles, and oxide-supported catalysts. Emphasis is placed on key reactions including CO and NO oxidation–reduction, CO and CO₂ hydrogenation, Fischer–Tropsch-related pathways, and reforming of ethanol. Advanced surface-sensitive techniques (TDS, XPS, UPS, IR, HREELS) are highlighted for their role in elucidating intermediate structures and reaction pathways. The isocyanate surface complex is an existing intermediate in NO reduction with CO, and NCO is responsible for NH₃ formation. Alkyl groups can be prepared from thermal- or photo-induced dissociation of alkyl halogenide. Oxygen-containing intermediates relevant to CO₂ hydrogenation are addressed, with particular attention to formate, carboxylate, and related species. M/CeO₂ (M = Pt, Rh, Ir, Ru) seems to be the best catalyst for hydrogen production from ethanol reforming. The nature of support may affect hydrogen production. The review also discusses how metal–support interactions, particle size, and surface morphology influence intermediate stability and catalytic selectivity. Overall, the work provides a comprehensive framework for understanding how transient surface complexes control technologically important catalytic transformations. Full article

Background: Green logistics requires decision-support approaches that jointly address cost efficiency, emissions reduction, service reliability, and reporting transparency under dynamic operating conditions. Existing studies often treat optimization, predictive updating, stakeholder coordination, and emissions traceability separately, limiting integration. Methods: This study develops a simulation-based integrated decision-support framework that combines multi-objective mixed-integer linear programming (MILP), machine learning-based travel-time prediction in a rolling-horizon setting, cooperative allocation using a Shapley value mechanism, and ISO 14083:2023-aligned emissions accounting. A permissioned blockchain layer is included as a post-decision governance mechanism to support traceability. The framework is evaluated using industry-calibrated synthetic scenarios over a 30-day planning horizon with 50 independent simulation runs. Results: Under the tested scenarios, the integrated configuration reduced average CO₂ emissions per route by 27.6% (±2.4%), improved the cost index by 17.3% relative to the baseline, and increased on-time delivery to 96.8%. Robustness analyses showed average key performance indicator (KPI) deviations below 5%. Component-level analysis suggests that the main operational gains arise from the interaction between predictive updating and prescriptive optimization, while the blockchain layer mainly improves auditability. Conclusions: The framework improves environmental and operational performance under the tested simulation scenarios, although real-world validation remains necessary before deployment-level conclusions can be drawn. Full article

Energy efficiency and sustainability are core issues in the modern design and management of industrial machinery and plants. These concerns are reflected and reinforced by the Sustainable Development Goal 9 of the United Nations (SDG9), “Industry, innovation and infrastructure”, which enshrines efficiency and optimized energy use as key features of sustainable production systems. As the engineering of industrial machinery reorients itself towards energy sustainability, attention is naturally shifting to actuators, since these components unavoidably waste part of the considerable amount of energy they absorb to execute their functions. Hydraulic actuation systems, while uniquely suited to heavy-duty applications, are particularly affected by poor energy conversion efficiency, in part due to their intrinsic properties but also because of outdated yet still common industrial practices. Consequently, for this actuation technology, there are wide margins for improvement in terms of energy waste reduction and increased environmental sustainability. This paper, therefore, investigates new applications for a management and control method conceived by the authors to drastically and systematically reduce the energy consumption of hydraulic actuators. The method is easily retrofittable to existing plants, being based on the unconventional and non-invasive deployment of a continuous-control electrohydraulic valve (CCEV) to control the supply pressure, whose required value is estimated according to the instantaneous load demands. Through the simulation of several industrial processes characterized by process parameters of varying orders of magnitude, this paper demonstrates that this innovative use of a CCEV for supply pressure regulation is an effective and widely applicable solution for energy savings and CO₂ footprint reduction in production systems that rely on hydraulic servo axes. Full article

This study investigates the environmental and energy performance of rice straw-based energy pathways in Egypt, combining life cycle assessment (LCA) with supply chain optimization to improve system efficiency. The analysis covers thirteen governorates producing over 4.45 million tons of rice straw annually. It examines the whole supply chain from paddy farming, straw collection, and transport to electricity generation and ash disposal. Total energy consumption was 11,287 TJ, dominated by farming (5673 TJ) and transport (5490 TJ). Greenhouse gas (GHG) emissions were estimated at 12,007.5 million kg CO₂-eq, with significant contributions from farming (5158 million), combustion (3630 million), and natural gas use (3039 million). Gross electricity output was 5525 GWh, yielding a net of 4973 GWh, equivalent to 1116.5 kWh per ton of straw. Scenario analysis highlighted that the optimized multi-hub system, prioritizing Cluster 1 in the Nile Delta, which contributes over 92% of straw production and 4607 GWh of net electricity, achieved a reduction of more than 25% in transport distances and an 18% decrease in diesel consumption and related emissions. Sensitivity analysis further indicated that delivered electricity and GHG intensity are more sensitive to conversion efficiency and transmission and distribution losses than to moderate changes in transport assumptions. In addition to environmental improvements, the optimized scenario indicates potential social co-benefits, including rural employment generation, additional income opportunities for farmers, and improved air quality associated with reduced open-field burning. These outcomes are presented as indicative qualitative insights. Findings confirm rice straw as a strategic, scalable, and sustainable energy resource aligned with Egypt’s Vision 2030 and the UN Sustainable Development Goals (SDGs). Full article

This study investigates the leaching behavior of the LiNi_0.65Co_0.25Mn_0.10O₂ cathode material in a phosphoric acid medium, with metallic copper recycled from spent battery components serving as a reducing agent. The aim was to develop an efficient approach for the recovery of Li, Ni, Co, and Mn while providing a mechanistic understanding. Leaching experiments were performed by varying key parameters, including copper addition, acid concentration (0.2–0.8 mol·L⁻¹), cathode mass (0.2–1.0 g), stirring rate (0–600 rpm), and temperature (35–80 °C). Thermodynamic analysis, supported by Pourbaix and species distribution diagrams, was used to interpret metal behavior. The results show that lithium is readily dissolved, whereas the extraction of Ni, Co, and Mn depends on the presence of copper, which enables their reduction and dissolution. Optimal conditions (0.4 mol·L^‒1 H₃PO₄, 0.2 g Cu, 600 rpm, 80 °C) enabled rapid extraction, exceeding 90% within 30 min, while near-complete extraction (~100%, 99%, 99%, and 97% for Li, Ni, Co, and Mn) was achieved after 60 min. Structural analysis revealed a transformation from the layered structure to spinel-like intermediates, followed by their dissolution and formation of copper phosphate phases. The proposed system represents an efficient approach for the sustainable recycling of NMC cathodes. Full article

Background: Genistein and resveratrol are bioactive compounds isolated from plants, recognized for their diverse biological activities including anti-cancer properties. Both compounds are also known as modulators of various types of ion channels, including voltage-gated potassium channels, Kv1.3. These channels are widely expressed in normal and cancer tissues. Their activity is crucial in regulating cell proliferation and apoptosis in cells that express Kv1.3 channels. The potential clinical application of channel inhibitors may extend to treating cancers characterized by an overexpression of these channels. Methods: This study investigates the inhibitory effects of genistein and resveratrol on Kv1.3 channels expressed in the cancer cell line Jurkat T by applying a whole-cell patch clamp. Results: Applying both compounds at concentrations ranging from 3 μM to 90 μM leads to a dose-dependent inhibition of channel activity, reducing it to approximately 50% of the control level. This inhibitory effect was reversible and associated with a significant reduction in the activation rate. When combined with simvastatin, the inhibitory effect exhibited synergy; however, it was additive when co-applied with mevastatin. Conclusions: The channel inhibition may putatively be linked to the anti-cancer activities of these compounds on Kv1.3 channel-expressing cancer cells, especially when co-applied with the statins. Full article

Electrocatalytic nitrate reduction to ammonia (NH₃) offers a sustainable alternative to the Haber–Bosch process while enabling remediation of nitrate-contaminated water. However, the mechanistic origin of performance differences among bimetallic catalysts remains poorly understood, particularly regarding the metal-dependent evolution of reaction intermediates. Here, we construct a series of phase-pure tandem Cu–M catalysts (M = Co, Ni, Fe, Sn) by physically integrating commercial nanoparticles to examine the role of the secondary metal. In this architecture, Cu governs nitrate adsorption and its initial reduction to nitrite, whereas M dictates downstream hydrogenation toward NH₃. Operando ATR–FTIR spectroscopy reveals that NH₃ FE is determined by the hydrogenation kinetics of nitrite-derived intermediates rather than nitrate activation itself. Among the examined systems, Cu–Co achieves optimal kinetic matching, enabling rapid nitrite consumption and continuous hydrogenation, delivering an ammonia Faradaic efficiency of 91.2% with minimal nitrite accumulation (~1.0%) and a yield rate of 0.86 mmol h⁻¹ cm⁻² at −0.5 V vs. RHE. In contrast, Ni and Fe exhibit sluggish hydrogenation, while Sn induces pronounced intermediate buildup. These findings identify nitrite hydrogenation as the selectivity-determining step in tandem nitrate reduction and establish the chemical nature of the secondary metal as a decisive descriptor for rational catalyst design. Full article

To address the critical challenges of sluggish C-C coupling kinetics and the propensity for over hydrogenation to ethane (C₂H₆) in the photocatalytic CO₂ reduction to ethylene (C₂H₄), this study designed a synergistic bimetallic Pt/Co cluster catalyst supported on a covalent organic framework (COF), designated as PtCo-TpBD COF. This catalyst is designed to modulate the adsorption of key intermediates via Co clusters to suppress over-hydrogenation, while leveraging Pt clusters to promote C-C coupling, thereby achieving highly selective C₂H₄ production. Through a series of structural characterization analyses, it was confirmed that Pt/Co clusters were successfully confined within the pores of the COF, and significant electronic interactions were observed. In situ infrared spectroscopy revealed that the introduction of Co clusters effectively weakens the adsorption strength of the CO* intermediate, while the incorporation of Pt clusters promotes C-C coupling. In visible-light-driven gas-phase CO₂ reduction, this catalyst delivered exceptional activity, reaching an C₂H₄ formation rate of 7.54 μmol g⁻¹ h⁻¹ and an C₂H₄ selectivity of 90.1%, along with remarkable inhibition of deep hydrogenation byproducts including C₂H₆. This study not only provides a successful example for constructing efficient bifunctional photocatalysts to achieve highly selective conversion of CO₂ to C₂H₄, but also highlights the great potential of COFs as advanced platforms for integrating multifunctional metal clusters and precisely tuning catalytic selectivity. Full article