The high sulphur content of end-of-life tyres restricts the use of pyrolysis products. In-situ desulphurisation using waste-derived additives is a promising solution. However, comparing additives across different studies is unreliable due to varying experimental setups and conditions. In this work, we established a systematic screening framework for fifteen distinct materials under identical reactor configuration, heating rate, and operational conditions. We evaluated dolomite, eggshell, alginite, mussel shell, zeolite, bone meal, deposited ash, fly ash, red mud, and their calcined counterparts. Experiments were carried out in the same batch reactor at 500 °C and 900 °C using a 1:1 tyre-to-additive mass ratio. At 500 °C, calcined Ca- and Mg-rich additives reduced the sulphur content of the pyrolysis oil from 1.3 to 0.6 wt%. However, this caused a product trade-off, as the oil yield decreased from 47.8 to 35.0 wt%. Bone meal increased the oil yield to 69.6 wt% but did not capture sulphur. At 900 °C, the thermal cracking intensified and shifted the sulphur into the gas phase. Calcined zeolite produced up to 40.0 wt% gas. Higher temperatures diminished the effect of liquid-phase desulphurisation, keeping oil sulphur levels between 0.9 and 1.3 wt%. Deposited ash retained the most sulphur in the solid phase (77.9 wt% at 500 °C) but increased the char ash content to 72.3 wt%. These results quantify the necessary trade-offs between oil quality, product yields, and multi-phase sulphur distribution.
Groundwater salinization threatens water security for 30,000 inhabitants of Siwa Oasis, Egypt, who depend on two aquifer systems: The shallow Tertiary Carbonate Aquifer (TCA) and deeper Nubian Sandstone Aquifer (NSSA). This study elucidates salinity sources and quantifies inter-aquifer mixing dynamics using an integrated approach combining self-organizing map (SOM) analysis, NETPATH inverse modeling, multiple isotopic tracers (δ1⁸O, δ2H, ⁸⁷Sr/⁸⁶Sr, 13C, 14C), and 3D numerical modeling with reverse particle tracking. Analysis of 153 water samples revealed three distinct hydrochemical groups: High salinity TCA waters influenced by evaporation and recharge from salt lakes, intermediate salinity mixing zones, and low-salinity NSSA paleowaters aged 4,300–14,200 years. Salt lake contributions to TCA groundwater salinity range from 0.6–18
In this work, the effect of a custom-made, Na- and Ca-free flux on the melt quality of an Al–5Mg–2Fe alloy was studied. The composition of the flux mixture was designed based on thermodynamic calculations as well as previous studies. Melt quality was assessed by using (i) reduced pressure tests with density measurements and Bifilm Index analysis, (ii) microscopic investigation of K-mold samples, and (iii) tensile testing. Defects on fracture surfaces and the microstructure of tensile specimens were investigated by optical and scanning electron microscopy (SEM). Tensile data were analyzed via Weibull statistics. Results indicated that flux addition improved melt quality indices and tensile data only slightly, mainly due to the disappearance of old, coarse oxide films from the fracture surfaces of K-mold and tensile specimens. However, further improvements are needed for a more complete elimination of defects to increase the reliability of mechanical properties. This study provides insight into how fluxing treatments can alleviate the contribution of entrainment defects to the degradation of the mechanical properties of Al–Mg–Fe alloys.
The operation of carbon-emitting technology (CET), carbon-capture (CC), and carbon-utilization (CU) technologies should be harmonized. The operation of carbon-capture technologies is determined by both CET and CU. In the case of oxyfuel technologies, however, it is generally assumed that no carbon capture is required. The goal of this work is to analyze the technical aspects and costs of different approaches to utilize CO2 in the flue gas of oxyfuel combustion technology. Two options are examined: (i) utilization of CO2 in the gas phase and (ii) utilization of CO2 in the liquid phase. It is evaluated for both options whether a carbon-capture process is required or not. Solvent-based carbon-capture methods are considered, where the solvents are pressurized water-based or amine-based processes. Results show that the CO2 utilization process determines the flue gas processing. If we need clean CO2, carbon capture significantly improves CO2 purity, making it suitable for direct use in various applications. Among the evaluated methods, the water-based process with dehydration offers the best balance of efficiency, cost, and low emissions. Although the "Without Capture" scenario has the lowest energy consumption and the lowest CO2 emissions, the CO2 produced has the lowest purity, and therefore, this alternative cannot be used if high-purity CO2 is required by the carbon-utilization process. The comprehensive investigation clearly shows that the three processes, carbon-emitting technology, carbon capture, and carbon utilization, should be treated as one integrated system, and global optimization must be applied.
Featured Application Real-time, sustainability-aware fleet allocation for urban micromobility-based last-mile logistics using convex optimization and zone-level backlog dynamics within Industry 4.0 environments.Abstract Urban last-mile logistics systems must improve service responsiveness while reducing environmental impact. While micromobility-based delivery fleets offer significant emission advantages compared to conventional vans, their operational efficiency depends on adaptive, data-driven capacity allocation. We develop and analyze a real-time optimization framework that explicitly integrates sustainability considerations into zone-level fleet allocation decisions. The continuous-time backlog dynamics admit a closed-form discrete-time prediction, enabling computationally efficient rolling-horizon fleet reallocation. Sustainability is explicitly embedded through zone-specific emission factors and a multi-criteria objective function balancing backlog reduction, environmental impact, and operational stability. In a ten-zone numerical case study with a fleet of 40 vehicles, the proposed method reduced backlog in all zones within a 15-min interval while preserving strict feasibility and stability (spectral radius is less than 1). The framework also demonstrated a controllable emission-service trade-off via sensitivity analysis. These results suggest the practical applicability and real-time suitability of the proposed Industry 4.0-aligned optimization approach.
