Renewable energy and voltage source inverter-driven microgrids generally lack natural inertia to provide transient energy support during sudden load demands. Thus, the virtual synchronous generator (VSG) is a state-of-the-art control technique applied for power controllers to emulate virtual inertia during sudden load changes. This allows stable power delivery from the source to the loads during sudden active power load demands. However, in the case of large inductively dominant load demands, the VSG-based power controller's power delivery capability is relatively poor. To address this limitation of VSG control, this paper proposes an advanced control scheme in which VSG is supported by appropriately designed voltage and current controllers. Conventionally, classical tuning techniques were used to design the controllers in the forward paths of the voltage and current controllers (CVA). Accordingly, the conventional control scheme is a combination of VSG and CVA. Recently, the hybrid-modified-pole-zero-cancellation technique has been discussed in the literature for the design of voltage and current controllers (HVA) to improve the vector control of the inverter. This method supports better tuning for controllers of both forward and cross-coupling paths. Thus, to improve the power delivery with VSG-based control when subjected to inductive load changes, this paper proposes an advanced control scheme that is based on the combination of VSG and HVA. The performance of both conventional and proposed control schemes is verified through simulation in MATLAB/Simulink under two different test load conditions, namely good and poor power factor loadings. Based on the results obtained during these test cases, the response and power delivery capability of the proposed control scheme is compared with that of the conventional control scheme. From the results, it is verified that the power delivery capability of the microgrid with the proposed control scheme is improved by 25% than the conventional control scheme.

The increasing demand for sustainable energy solutions in transportation has driven significant advancements in renewable energy technologies, with applications in electric vehicle charging stations, for example. Thus, a hybrid fuel cell and solar-powered charging station for micro-mobility, where such local transportation is utilized, would be beneficial. Moreover, such a hybrid charging station can be used to promote STEM education as it showcases the integration of solar-energy panels and hydrogen fuel cell technology to provide a sustainable power solution for micro-mobility and portable devices. This project aims to address the growing demand for eco-friendly transportation options while serving as an educational tool for science and engineering students. The methodology involved assembling, testing, and evaluating a system composed of a solar panel of up to 200 W, a solar charge controller, a set of battery banks, a hydrogen generator, a fuel cell, and a power inverter. The preliminary results indicated that while the system could power various devices from a fan of 3 Watts to a laptop of about 90 Watts, the hydrogen generators underperformed a bit to run at sub-optimal pressure at a flow rate of about 1 L/min, and thus limited the fuel cell's performance to below 100 Watts. The solar charging system successfully charged batteries to power the hydrogen generator for the tested duration.

Organic solar cells have gained significant attention in recent years due to their properties of having low material costs, being lightweight, and undergoing high-throughput roll-to-roll production. However, their low efficiency and stability remain major challenges. Through our study, we aimed to address these issues by optimizing the optical and structural properties of the active layers to enhance performance and stability.
Here, we investigated how optical interference impacts device performance. Solar cell efficiency is influenced by various factors, including the materials used within their structures. To analyze the impact of structural geometry, we used bulk heterojunctions with P3HT as the donor layer and PCBM as the acceptor layer, forming the active layers. We examined various computed optical properties, such as the intensity of optical electric fields, the generation rate, absorption profiles inside the device, and reflection within the device. Additionally, we calculated the short-circuit current density concerning the active layers and found a high value of 11.35 mA/cm² for P3HT:PCBM active solar cells, which corresponds to the high absorption within the device structure. High performance was achieved in the case where high absorption was localized within the active-layer cells using the finite element method. The numerical simulation, conducted with COMSOL Multiphysics software, shows a strong correlation with published experimental data.

Intraspecific behavioural variability (e.g., coping styles) ensures an optimal adaptive response to environmental stressors. These individual stress-coping skills are expressed along a fundamental axis of behavioural variation, the bold-shy continuum. Exposure to neuroactive compounds intended for human use, like paroxetine, may affect behavioural phenotypes, through action on evolutionarily conserved neurological pathways found in humans and other species, such as teleost fish, even at low doses. Although paroxetine is prevalent in water systems worldwide at concentrations in the ng/L range there is no available data on its influence on fish coping styles. Accordingly, this study aimed to assess if early exposure (up to 48 hours post fertilisation (hpf)) to PAR environmental levels (0.04 and 0.4 µg/L) may compromise zebrafish's (Danio rerio) bold and shy behavioural phenotypes at later-life stages (larval and juvenile). The obtained data show that both larval and juvenile stages are sensitive to early-life PAR exposure, as differences between bold and shy behavioural profiles were lost at 8dpf (larval stage) and 45dpf (juvenile stage) for basal swimming activity and stress response (e.g. total swimming distance, inactivity time, thigmotactic behaviour, boldness). These results highlight the need for further studies to understand the ecological implications of these behavioural phenotype modifications.

There has been a recent trend to replace petroleum-based plastics with greener and more sustainable alternatives, such as bio-based ones. During this transition, there is a high probability that both types of polymers will be encountered and interact in environmental matrices. An integrated ecotoxicological test, that is, covering standard physiological parameters, such as mortality or growth, with behavioural characteristics, can be extremely important to understand the potential environmental and human impacts of these mixtures. This study aimed to evaluate the effects on Danio rerio embryonic-larval stage of exposure to micro(nano)plastics of polyhydroxybutyrate (PHB-MNPLs) and polymethylmethacrylate (PMMA-MNPLs) at concentrations of 0.1, 1, 10, 100, and 1000 µg/L on a full cross design. A control group was also included. Generally following the OECD 236 Fish Embryo Toxicity (FET) adapted for a period of 120 hours, the following endpoints were observed: mortality, malformations, heartbeats (only at 48 hours), hatching rate (starting at 48 hours), and overall length (at 120 hours). At 120h of exposure, the total time active, the total distance swum, thigmotaxis behaviour, and trajectory angles were analyzed.

The individual exposure to PHB-MNPLs and PMMA-MNPLs had no impact on mortality, malformations, or hatching rates of D. rerio. The PMMA-MNPLs alone induced tachycardia at 100 and 1000 µg/L and reductions in larvae length at concentrations between 0.1 and 100 µg/L. The PHB-MNPLs induced effects on fish swimming-related parameters, similar to those induced by PMMA-MNPLs (decreased total time active under light periods; decreased high amplitude movements at 0.1-10 µg PHB-MNPLs/L. These effects were also observed at 100 and 1000 µg PMMA-MNPLs/L under light periods. The mixture of both polymers induced patterns of response different than those observed for both MNPLs alone (e.g., in heartbeat rates and swimming parameters). This study highlights the need to Assess the effects of combined nanoparticles of different polymers.

Plastic additives comprise many substances that serve numerous purposes in the plastic industry, such as assisting in the moulding of plastics and improving optimal performance. One of the bisphenols, namely, bisphenol A (BPA), is a widely used additive in the plastic industry and is now restricted by the European Union due to its proved toxicity. This additive is being replaced by analogues such as bisphenol E (BPE) and bisphenol Z (BPZ). However, there is a need to better understand their potential toxic effects to validate if they constitute safer alternatives. Thus, this study aimed at making a comparative assessment of the cytotoxicity of BPA, BPE, and BPZ to amphibian cell lines (A6 and XTC-2 - cell lines of Xenopus laevis), as Amphibia is the class of vertebrates with the highest proportion of species threatened with extinction. The cell lines were exposed for 24 h, 48 h, and 72 h to eight concentrations of each bisphenol and cell viability was assessed through each time point. Overall, the median lethal concentrations (LC₅₀) revealed that A6 cells are more sensitive to these chemicals than XTC-2. The obtained data support the premise that BPE and BPZ are less toxic to amphibian cell lines than BPA. Thus, based on the 72h LC₅₀, the cytotoxicity can be ranked as BPA>BPZ>BPE (45.48 mg/L, 57.1 mg/L, and 64.7 mg/L, respectively) for XTC-2 cells. A similar trend was observed for A6 cells (24.6 mg/L, 32.1 mg/L, and 41.6 mg/L for BPA, BPZ, and BPE, respectively). Thus, the data support that these BPA alternatives appear less toxic, but more studies must be performed and other endpoints assessed to fully understand their highest environmental safety.

One of the critical elements of the so-called circular green transition is to move from waste minimization to materials circularity, i.e. to implement a systems engineering approach in which the residues of a process are not seen as waste but as a resource to another process of an integrated circular economy network. So, this study aims to apply a circularity assessment of municipal waste management scenarios combining Life Cycle Assessment (LCA) and Material Flow Analysis (MFA) approach. Four scenarios were considered: scenario 1: the existing conditions of the system, scenario 2: based or recovery of the organic fraction by composting, scenario 3: focused on the circularity of the organic fraction by anaerobic digestion, scenario 4: using recycling and incineration. The LCIA approach used was CML 2001. The circularity of each scenario was compared in terms of materials and energy recovery and effect of circularity solutions in the impact categories. A multicriteria analysis was used to aggregate the results of circularity in all impact categories and obtain a ranking of scenarios to determine the final result. From the results it could be noted that even if the three considered scenarios correspond to a significant improvement compared to the base scenarios in terms of materials recovery, scenario 4 was ranked in first place as it results in both materials and energy recovery rates higher than the others. Moreover scenario 4 also has less impacts related to the emissions involved during the biological processing of the organic fraction, mainly eutrophication and acidification potential. So, the LCA approach was shown to be an efficient way to support circular economy assessment by providing a more holistic circularity overview than considering only MFA.

Perovskite solar cells are expected to be alternative materials to silicon solar cells because of their high conversion efficiencies and easy device fabrication with various compositions. Recently, research is being conducted to develop low-cost and flexible devices. For the typical CH₃NH₃PbI₃ perovskite, CH₃NH₃ (MA) migration and high reactivity have a significant impact on instability and low durability in the atmosphere. To solve this problem, research has been conducted to improve crystal stability by introducing elements and molecules into perovskite crystals. Among organic molecules, guanidinium (GA), which has three different resonance structures and is stable, and ethylammonium (EA), which has a larger ionic radius than MA, will contribute to crystal stabilization by introduction into the crystal lattice. Additionally, alkali metal cations are expected to be difficult to desorb due to their inorganic nature. In this study, effects of substitution of halogen anions and addition of alkali metal cations for GA/EA-doped perovskite solar cells were investigated by fabricating devices and comparing their photovoltaic properties. The halogen compositions of the additives were found to contribute to the improvement of preferred orientations of perovskite crystals, and the order of the effectiveness was I, Cl, and Br. In addition, the addition of alkali metal cations contributed to improvement of the conversion efficiencies, and addition of a small amount of cesium at the MA site was the most effective. It was also found that the short-circuit current densities and fill factors depended on the (100) preferred crystal orientation of the perovskite compounds.

Several studies have been conducted on Ultra-High Performance Concrete (UHPC) to enhance the mechanical properties of this construction material, but the benefits of this new material to the natural environment is still to be assessed. So, this study aims at comparing the environmental impacts of conventional concrete and UHPC with graphene oxide (GO) by applying life cycle assessment (LCA). Four scenarios were considered in the LCA: (1) conventional concrete, (2) UHPC without graphene, (3) UHPC with a low content of GO, and (4) UHPC with a high content of GO. The compression strength for these scenarios was 30 MPa, 160 MPa, 160 MPa, and 180 MPa, respectively. The LCA was carried out in four phases: goal and scope definition, Life Cycle Inventory (LCI), Life Cycle Impact Assessment (LCIA), and Result Interpretation. For impacts per m³ of concrete produced, scenarios with UHPC (scenarios 2, 3, and 4) led to a much higher environmental impact (2,5 times higher) for most of the impact categories compared to conventional concrete results (scenario 1). For impacts per MPa of compression strength, the UHPC scenarios showed a much lower environmental impact than scenario 1. Notably, the higher strength UHPC, with the higher content of GO (scenario 4), resulted in a lower environmental burden due to a higher increase in strength due to the GO addition compared to the increase in impact. Therefore, UHPC with GO has a high potential to support more environmentally friendly construction if it results in less demand for concrete.

The formulation of ecofriendly coating compositions with protective properties against corrosion and/or mechanical degradation requires appropriate selection of bio-based binders and functional additives. Although the concentration of additives remains limited, they highly contribute to the enhanced lifetime and may alter processing conditions of the coating. Their influences on processing conditions also affect the selection of appropriate end-of-life options with specific technological challenges on recycling and re-processing of the coating. Therefore, the replacement of fossil-based additives into bio-based additives may deliver an important contribution improving the carbon footprint of a coating over its full lifetime. However, the role of bio-based additives in life-cycle analysis is often neglected and minorly considered, as up to present only few dedicated case-studies have been identified in literature. Reasons for this are further pointed out in this paper, including lack of data, methodological inconveniences and appropriate design of realistic scenarios. Within this work, a simplified approach is followed by ab-initio cradle-to-gate analysis of coating compositions focussing on the replacement of specific fossil additives into bio-based additives. Particular case-studies are presented in relation with replacement of carbon black, silicates, calcium carbonate into biochar, bio-based wax and recovered calcium carbonate. There is a main interest in improving coating performance by substituting cellulosic additives into nanocellulose from different sources, where environmental benefits are associated with their high performance at low concentration. The environmental impact parameters (human health, ecotoxicity, resource scarcity, carbon footprint) are calculated from ecocost analysis (Idemat 2024 v2.2 database) indicating a 15 to 30 % gain in environmental footprint for given coating formulations. The need for intermediate processing of the bio-based additives is a main parameter contributing to their environmental impact, but is abundantly compensated by their carbon storage credit and performance improvement.