The coexistence of iron particles and humic acid (HA) in drinking water distribution systems presents complex challenges for disinfection safety. This study ‌revealed the synergistic effects between iron particles and HA in promoting disinfection by-product (DBP) formation. Experimental characterization demonstrated that HA coordination induced surface reconstruction of iron particles, increasing their specific surface area by 34.2% (from 39.84 to 53.46 m²/g) and creating abundant active sites for chlorine activation. Remarkably, HA exhibited ‌dual functionality‌ for iron particles: (1) as a catalytic promoter, it elevated FeOOH content and perfluorooctanoic acid accumulation, intensifying DBP formation risks through transformation of particle interface; (2) as a colloidal stabilizer, it increased specific area via electrostatic repulsion, generating predominantly submicron particles (< 2 μm) with elevated environmental persistence to generate more active sites. The identified synergy effects of iron particles and HA on DBP formation provide critical operational guidance for optimizing disinfection strategies in iron corrosion-prone pipe networks within HA-enriched water systems.

The removal of heteroatoms and trace metals such as vanadium, nickel, and sulfur from heavy crude oil remains a critical challenge in the petroleum industry due to their adverse impact on refining processes and the environment. This study investigates the effectiveness of different additive systems in reducing these contaminants in crude oil from the East Baghdad oil field. A comprehensive comparative evaluation was conducted using individual surfactants, sodium dodecylbenzene sulfonate (SDBS) and sodium lauryl sulfate (SLS), alumina (Al₂O₃) nanoparticles, pure kerosene, a kerosene–alumina mixture, and a novel ternary nanofluid composed of kerosene, alumina nanoparticles, and SDBS. The alumina nanoparticles were characterized using thermogravimetric analysis (TGA), X-ray diffraction (XRD), and atomic force microscopy (AFM) to confirm their thermal stability, crystalline phase, and surface morphology. Ultrasonic-assisted dispersion was employed at varying temperatures (20 °C to 75 °C) and exposure durations (15–60 min). The ternary nanofluid demonstrated superior performance, achieving maximum reductions of 90% in vanadium, 86% in nickel, and 70% in sulfur content at 75 °C after 60 min. These results highlight the synergistic interaction among the surfactant, solvent, and nanoparticles, suggesting a promising, energy-efficient pathway for the selective removal of heavy metal and sulfur contaminants from crude oil. This study contributes a scalable and environmentally conscious approach to advancing the purification of heavy crude oils using nanofluid-assisted ultrasonic treatment.

Increasing shares of variable renewable electricity sources in the energy system extend the demand on flexibility providers, such as hydropower. More short-term regulation of hydropower plants adversely affects river ecosystems, particularly in cascades. Implementing environmental flow constraints is a well-recognised method to ensure qualitative habitat improvements. The study aims to evaluate the effects of flow constraints by modelling a national-scale energy system with a hydro cascade enhanced with hydrological details for hydropower operations. The open-source modelling framework Backbone is employed for the techno-economic simulation. Studied scenarios cover different years, a range of flow constraints, and options for additional flexibility investments to mitigate the economic impact of flow constraints. Results indicate that flow constraints reduce revenue but mitigate sub-daily ramping. In scenarios with highly volatile electricity prices, low-level flow constraints do not lead to significant reductions in electricity production. However, the simulation still reveals a revenue decrease. Moderate price levels lead to larger relative losses and require more generation from thermal power plants. Incorporating energy storage units reduces economic losses and emissions, underscoring their potential as alternative flexibility providers in the energy system. Introducing a medium-restricted scenario featuring a large energy storage unit seems viable for balancing environmental and economic impacts.

Hydrothermal condition is one of the most important factors influencing fish reproduction. Successful reproduction requires that both the critical temperature (CT) and accumulated temperature (AT) thresholds are reached at appropriate times. This study addressed two key questions: (a) What mechanisms enable climate change and reservoir impoundment to influence the attainment of CT and AT thresholds and their match relationship by fish? (b) How can the matching theory between CT and AT thresholds be applied in practical assessments? To address these questions, a conceptual framework was developed. The framework was applied to the upper Yangtze River to evaluate the effects of climate change and the Xiangjiaba (XJB) reservoir on the reproductive hydrothermal conditions of the Yangtze sturgeon (YS). Results indicated that while XJB reservoir impoundment was the primary driver of changes in the river’s natural hydrothermal regime, climate change made a substantial contribution to the interaction effect. The match degree of alignment between the timings of CT and AT thresholds can effectively quantify the adverse effects of climate change on fish reproduction. Climate warming had reduced the suitable ecological niche in historical reproductive areas by 50%. Reservoir impoundment restored temporal alignment between thresholds in reproductive section, but further delayed start reproductive time, exacerbating conflicts between the long reproductive period and narrow reproductive window. The ecological niche suitable for YS reproduction quantified by match degree was narrower than that estimated using CT or AT alone. The methodology developed in the study provided scientific basis for optimizing reservoir ecological regulation and conserving rare fish species under climate change.

Thermal comfort inside buildings is a fundamental human need, yet meeting this need often entails significant energy consumption. The utilization of solar energy for building heating has been achieved through Trombe wall (TW) systems, which offer an eco-friendly and sustainable solution. This study aims to enhance the efficiency of TW systems by investigating the impact of adding fins to the solar radiation absorber. Addressing identified gaps in the literature, a transient 3D computational fluid dynamics (CFD) model is proposed to analyze the energy, exergy, and economic aspects of the finned TW. The turbulence is modeled using the k-omega model, while experimentally measured solar radiation intensities are incorporated via the Discrete Ordinates model. The transient analysis reveals that while air vortices naturally occur in Trombe wall systems due to buoyancy effects, the addition of fins intensifies these vortices, leading to more structured recirculation patterns, lower pressure zones, and non-uniform air velocity in the exit vent. The proposed finned TW demonstrates energy and exergy efficiencies of 61.45% and 3.35%, respectively. An economic analysis is conducted using a life cycle cost analysis, which indicates an optimal cost of 2950 TND (approximately 900 dollars) and a payback period of 0.7 years. This study confirms the effectiveness of utilizing prismatic vertical fins to enhance the performance of TW systems, requiring minimal investment costs.

This paper investigates the combined effect of energy efficiency renovations and smart readiness upgrades on an existing public building in Greece. Using a three-scenario approach—baseline (Scenario 1), energy upgrade (Scenario 2), and smart upgrade (Scenario 3)—the study evaluates the building’s energy performance, Smart Readiness Indicator (SRI), CO₂ emissions, and financial feasibility. Energy simulations were conducted using the national Energy Performance Certificate (EPC) software (TEE-KENAK), while smart capabilities were assessed via the European Union (EU) Method B for SRI evaluation. Economic viability was determined through Net Present Value (NPV), Internal Rate of Return (IRR), Return on Investment (ROI), and Discounted Payback Period (DPP) calculations. Results indicate that energy efficiency interventions in Scenario 2 reduce energy consumption by over 50% and improve the EPC class from E to B, with a favorable 15-year ROI of 111.95%, though it yields only a marginal increase in the SRI (9.2%). Scenario 3, which integrates smart technologies such as zonal thermostats, automated lighting, and a Building Management System (BMS), further boosts performance—achieving EPC Class A and increasing the SRI to 52.1%—but entails higher upfront costs and a longer payback period. The findings highlight the need for integrated renovation strategies that combine passive and smart interventions to enhance building functionality, reduce emissions, and align with EU climate goals.