Search Results (1,287)

Green consumption research has long documented a gap between favorable environmental attitudes and concrete sustainable choices. Yet less is known about why consumers who value sustainability sometimes doubt that their own actions can matter. Across five studies of Chinese consumer samples (N = 1499), this article develops an efficacy-translation account of green consumption. The account proposes that global self-esteem is associated with perceived consumer effectiveness (PCE), the belief that individual consumption can contribute to environmental improvement. It therefore specifies PCE as a domain-specific collective-impact belief rather than as a generic efficacy construct. The evidence incorporates trait and state self-esteem, measured and manipulated PCE, and multiple green-consumption outcomes, validated by robust regression, bootstrap mediation, internal meta-analysis, specification-curve analysis, and a limited computational audit. Self-esteem was positively associated with green consumption across the five studies, with a random effects pooled association of $r=0.164$, 95% CI [0.114, 0.213]. In Study 2A, the measured indirect association through PCE was 0.105, 95% bootstrap CI [0.048, 0.164]. These results are consistent with PCE as one pathway linking self-worth to sustainable consumption, but they do not establish causal mediation or generalize beyond the sampled cultural context. Full article

This study examined the combined effects on highly foamed cementitious materials of varying concentrations of multi-walled carbon nanotubes (MWCNTs), an air-entraining agent (AEA), and three superplasticizers (SPs): a lignosulfonate-based superplasticizer (SP-LS), a polyacrylate-based superplasticizer (SP-PA), and a polycarboxylate ether-based superplasticizer (SP-PCE). Setting time, semi-adiabatic exothermic-temperature (EXO) profile tests, zeta potential analysis, pH and electrical conductivity (EC) measurements, and foam stability were used to assess the suspensions and pastes. Adding up to 1.5% MWCNTs to an alkaline air-entraining agent (AEA) and SP-LS mostly shifts the zeta potential toward a negative value and stabilizes the suspension and foam. When MWCNTs and SP-LS were added to the foamed paste, the initial viscosity dropped by 12.1% to 7%, whereas with SP-PA and SP-PCE it dropped by 20–48% and 18–50%, respectively. Adding MWCNTs and SP-LS to the foamed paste mostly decreases the density. Using SP-LS is very helpful for interactions between AEA and MWCNTs, thereby stabilizing the air bubble walls. This study underscores the importance of pH and EC of the AEA and SP in affecting the cement paste’s hydration process. Full article

Suppressing thermally driven morphological evolution while preserving efficient charge transport pathways remains a critical challenge for improving the long-term stability of organic photovoltaics (OPVs). Herein, a soft polymeric matrix strategy based on gel-related soft material concepts is demonstrated for stabilizing bulk heterojunction (BHJ) morphology and simultaneously improving the efficiency and thermal durability of OPVs. The incorporation of an optimal 5 wt% polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) as a soft polymeric matrix component into a PM6:Y6 blend modulates the nanoscale morphology and local packing characteristics of the acceptor phase. These changes improve charge-transport balance and charge collection, increasing the power conversion efficiency (PCE) from 14.27% to 15.22%, corresponding to a 6.7% relative enhancement over the control device. More importantly, after 10 days of thermal aging at 85 °C, the SEBS device retains 87.1% of its initial PCE, compared with 72.5% for the control device. Complementary morphological and spectroscopic analyses reveal suppressed thermally induced structural evolution and aggregation in the SEBS-containing films. These findings demonstrate that a gel-related soft polymeric matrix can regulate BHJ organization and mitigate thermally driven morphological evolution, providing a simple strategy for addressing the efficiency–stability trade-off and realizing thermally robust OPVs. Full article

The increasing demand for high-efficiency photovoltaic technologies has intensified research into tandem solar cells (TSCs) as a promising strategy to surpass the performance limits of single-junction devices. In this study, a comprehensive optoelectronic simulation using a Silvaco ATLAS TCAD simulator is employed to design, optimize, and compare two tandem architectures: all-organic and hybrid organic/silicon TSCs. The all-organic configuration consists of polymer donors comprising a PBDB-T:F-M top sub-cell stacked with a PTB7-Th:CO_i8DFIC:PC₇₁BM bottom sub-cell, while the hybrid configuration integrates a PBDB-T:F-M organic top cell with a crystalline Si bottom cell. Calibrated device models, validated against experimental data of the individual sub-cells, are used to evaluate tandem performance and guide systematic optimization. The two tandem architectures employ the same PBDB-T:F-M wide-bandgap organic top absorber (E_g~1.60 eV), while the rear sub-cell consists of either the PTB7-Th:CO_i8DFIC:PC₇₁BM organic absorber (E_g~1.20 eV) or crystalline silicon (E_g~1.12 eV). The initial organic/organic tandem device accomplishes a power conversion efficiency (PCE) of 15.70% and J_SC of 10.96 mA/cm², whereas the organic/silicon tandem structure exhibits a higher initial PCE of 16.85% and J_SC of 12.26 mA/cm². Following absorber-thickness optimization, the all-organic and hybrid OSC/Si tandems achieve PCEs of 19.44% and 21.13%, respectively. Rather than constituting a simple efficiency ranking, the comparison reveals distinct optical, electrical, and technological trade-offs. The hybrid architecture benefits from the broader spectral utilization and efficient carrier collection of thin crystalline Si, whereas the all-organic configuration offers advantages associated with low-temperature solution processing, reduced material consumption, and potentially fully solution-processed photovoltaic fabrication. The calibrated comparative framework therefore provides design guidance for selecting and optimizing TSCs according to both performance and application requirements. Full article

Enggal Jaya MSME is a small-scale enterprise specializing in metal casting and the production of fire rings, with a monthly capacity exceeding 15,000 units. Currently, its production process exhibits significant inefficiencies across the seven wastes of lean manufacturing: overproduction, defects, inventory, motion, transportation, overprocessing, and waiting. This study aims to map the information and production workflows for fire ring components, analyze the types and root causes of waste, and propose actionable solutions to improve shop-floor efficiency. Value Stream Mapping (VSM) and the Waste Assessment Model (WAM) were utilized as the primary methodologies. The current-state VSM revealed a Process Cycle Efficiency (PCE) of 69%, whereas the proposed future-state VSM demonstrates an improved PCE of 73%. Furthermore, Waste Assessment Questionnaire (WAQ) calculations identified five major types of critical waste: overproduction (19.2%), defects (18.0%), inventory (16.1%), motion (15.2%), and transportation (13.3%). Proposed countermeasures include systematically recording production activities, developing Standard Operating Procedures (SOPs), integrating appropriate material handling tools, and implementing rigorous production forecasting and scheduling. Full article

Organic solar cells are widely recognized for their flexibility, light weight and semitransparency, all relevant for niche applications. A significant challenge in their development lies in the accurate prediction of their power conversion efficiency depending on the combination of the donor and acceptor selected in the bulk heterojunction. To address this issue, we developed a robust machine learning (ML) framework designed to establish correlations between molecular structure and device performance. A feature selection strategy, incorporating SHapley Additive exPlanations and Boruta algorithms, was employed to extract the most informative descriptors. Among the regression models that were systematically evaluated on a curated dataset comprising 1575 experimentally characterized donor–acceptor pairs, histogram-based gradient boosting demonstrated superior predictive performance, giving an R² score of 0.79, with a low root mean square error of 2.16. Subsequently, the optimized model was used to predict new donor–acceptor pairs with PCEs above 20% and identify prospective candidates for further experimental validation. Full article

Passenger Car Equivalent (PCE) factors are widely used to convert heterogeneous traffic streams into equivalent homogeneous flow rates for the design and analysis of roads and intersections. In developing countries, mixed traffic conditions differ substantially from those in developed contexts due to variations in vehicle composition, operating characteristics, roadway parameters, and environmental conditions. Consequently, PCE values are highly context-specific and require periodic updates to accurately represent prevailing traffic conditions. However, such updates are often infrequent because conventional PCE estimation relies on extensive field data collection through time-consuming and costly traffic surveys, as well as the availability of experienced experts to conduct and validate the analyses. In Sri Lanka, the currently adopted PCE factors are more than two decades old and no longer reflect existing traffic conditions. Although several recent studies have estimated PCE values for mid-block roadway sections of various facility types (e.g., four-lane roads, two-lane roads, and freeways), no study has comprehensively addressed intersections, which are critical for signal timing and geometric design. This study aims to develop a systematic methodology for estimating intersection-specific PCE factors using drone-based video data. Traffic data were collected at selected intersections using an unmanned aerial vehicle to obtain an accurate bird’s-eye view of vehicle movements. The methodology compares the area occupancy of different vehicle categories under varying traffic compositions with that of a passenger-car-only traffic stream operating at the same average speed. Using the extracted traffic parameters, the basic headway method was applied to establish a framework for calculating PCE factors. PCE values were estimated for ten vehicle categories, and the results reveal significant deviations, particularly for three-wheelers, motorcycles, and commercial vehicles, when compared with values currently in use. A high-level comparison with studies from other developing countries in the South Asian region indicates notable differences in vehicle impacts at signalized intersections in Sri Lanka. Furthermore, the proposed methodology provides a practical, economical, and less labour-intensive approach for estimating PCE factors, enabling more frequent updates without requiring extensive field surveys or specialized expertise. Because it relies on a straightforward headway-based framework and drone-derived traffic data, the methodology can be readily adapted to different roadway facilities, including highways, rural roads, and intersections, making it suitable for application across diverse geographical regions. Full article

The development of indoor photovoltaic devices for powering Internet of Things (IoT) sensors requires low-cost and sustainable components, making dye-sensitized solar cells (DSSCs) an ideal candidate for artificial light harvesting. The counter electrode plays a critical role in transferring electrons and catalyzing the reduction in the redox electrolyte. However, the traditional use of expensive and scarce platinum (Pt) limits the cost-effective, large-scale commercialization of these devices. While carbon-based materials offer a highly porous, conductive, and abundant alternative, commercial carbon pastes frequently require energy-intensive high-temperature sintering. In this study, we propose a sustainable, low-temperature, and screen-printable carbon composite counter electrode (LoT-HPC) using bio-derived hydroxypropyl cellulose (HPC) as a highly effective binder. Rheological characterizations confirm that the formulated LoT-HPC ink possesses an ideal shear-thinning profile and rapid structural recovery, ensuring excellent printability and film homogeneity. By comparing the custom LoT-HPC composite against a commercial high-temperature screen-printed graphite paste (HT-Elco) and a standard sputtered Pt-FTO electrode, we demonstrate the structural and electrocatalytic advantages of this material. When integrated into full DSSC devices and evaluated under low indoor illumination (1000 lux), the LoT-HPC cell delivers a power conversion efficiency (PCE) of 14.8% and a high short-circuit current density of 103.9 µA cm⁻². Furthermore, the custom device demonstrated exceptional operational stability, retaining 98.6% of its initial efficiency (from 14.8% to 14.6%) after 200 h of continuous light-soaking and J-V cycling under 1000 lux. Ultimately, the successful implementation of the HPC binder enables the low-temperature fabrication of sustainable carbon counter electrodes without the need for energy-intensive thermal treatments, presenting a highly scalable pathway for indoor DSSC manufacturing. Full article

Effective passivation of bulk and interface defects is one of the key drivers for achieving highly efficient and stable p-i-n perovskite solar cells (PSCs). Despite the versatility of bulky ammonium cations in defect passivation, ionic migration of these cations under light and thermal stresses is undesirable for maintaining the integrity of the passivation layer and thus detrimental to the device performance and long-term stability. To address this issue, a stepwise passivation approach employing 2-methoxyphenylethylammonium (2-MeO-PEA⁺) cation and piperazine dihydroiodide (PipDI) is proposed. By integrating bulk incorporation and subsequent surface treatment, the passivation approach synergistically mitigates both bulk and interface defects, and thereby enhances the resilience of the perovskite layer against light and thermal stresses. Owing to the significantly improved morphology, crystallinity, and optoelectronic properties of the perovskite layer, a champion PSC device with a PCE of 26.10% and outstanding stability is achieved, demonstrating the feasibility of the proposed two-step passivation approach. Full article

This study investigates cellulose nanofiber (CNF) suspension as a nano-reinforcement for underwater non-dispersible concrete, aiming to improve the balance among workability, washout resistance, and compressive-strength performance. An L9 orthogonal array was employed to evaluate the dosage-dependent responses of CNF suspension, hydroxypropyl methylcellulose (HPMC), and a polycarboxylate ether-based water-reducing admixture (PCE). Within the investigated range, increasing the as-received CNF-suspension dosage from 0.15% to 0.60% was associated with an increase in the factor-level mean 28-day underwater-to-air compressive-strength ratio from 0.75 to 0.79 and a decrease in suspension pH from 11.92 to 11.73, suggesting higher underwater strength retention and lower alkaline dispersion. CNF suspension showed favorable dosage-dependent responses in the washout-related and compressive-strength indicators, while HPMC and PCE contributed to the overall regulation of measured workability and compressive-strength performance. Among the nine mixtures, Group 5 was identified as a balanced engineering-oriented candidate, combining a slump of 245 mm, a slump flow of 465 mm, and 7- and 28-day underwater-to-air strength ratios of 0.94 and 0.82, respectively. SEM observations revealed pores, interfacial gaps, and locally distributed acicular, plate-like, and filament-like features, providing qualitative microstructural context for the measured responses. Overall, the results support the potential of CNF suspension as a promising nano-reinforcement for underwater non-dispersible concrete with a favorable balance of workability, washout-related performance, and compressive-strength retention. Full article

We report a two-layer computational workflow for designed heterocyclic polymer dimers as candidates for organic solar cell (OSC) materials. The workflow integrates geometry-optimized B3LYP/6-31G(d) quantum-chemical descriptors (HOMO, LUMO, gap, dipole moment) computed for five fully disclosed monomer–dimer pairs (1m–5m; 1d–5d), with a verified, literature-curated 17-entry OSC dataset (PCE 3.6–19.9%, years 2016–2024) modeled by a non-tautological ridge regression baseline (Model A; predictors Year + source_block + log10 hole mobility). All five dimers were computed under uniform neutral closed-shell conditions. Pareto-front analysis in the gap–dipole descriptor space identifies dimer 2d (difluorinated thiophene–diazine D-A dimer; gap 1.74 eV, dipole 16.59 D) as the Tier I lead candidate, with 3d (bis(thiophene–triazine) dimer) and 1d (bis-thiophene–thiazole dimer) as additional Tier I candidates. Model A yields R²(LOOCV) = 0.660, MAE = 2.36%, and RMSE = 3.67%, surviving a 500-shuffle permutation null at empirical p < 0.001. A descriptor-augmented Model B (Eg + HOMO added) demonstrates that the present literature dataset cannot support a deployable molecular-descriptor regression without expansion. The combined DFT–regression workflow provides a transparent screening framework that identifies 2d as the priority synthesis target. Full article

Perovskite tandem solar cells (TSCs) have emerged as a transformative photovoltaic technology, offering a viable pathway to surpass the Shockley-Queisser limit of single-junction devices by enabling broader solar spectrum utilization and reduced thermalization losses. This review provides a comprehensive overview of recent progress in perovskite-based TSCs, covering four major device architectures: perovskite/silicon, perovskite/CIGS, all-perovskite, and perovskite/organic TSCs. We systematically discuss the fundamental working principles, including bandgap engineering, charge generation and separation, and current-voltage matching, followed by an in-depth analysis of strategies for perovskite layer regulation, interface engineering, and transport-layer optimization. Key advancements, such as compositional engineering, defect passivation, crystallization control, and optical management, have synergistically pushed power conversion efficiencies (PCEs) beyond 34% for perovskite/silicon TSCs and over 28% for all-perovskite and perovskite/organic configurations. Despite these achievements, critical challenges remain, including material instability, halide phase segregation, lead toxicity, scalable fabrication, and cost-effective integration. This review also outlines future perspectives, emphasizing the development of lead-free perovskites, novel charge-transport materials, advanced encapsulation techniques, and large-area manufacturing processes. With continued interdisciplinary efforts, perovskite TSCs hold great promise for driving the global transition toward sustainable and low-carbon energy systems. Full article

Perovskite solar cells (PSCs) have emerged as one of the most rapidly advancing photovoltaic technologies of the past decade, progressing from the initial demonstration of 3.8% power conversion efficiency (PCE) in 2009 to certified single-junction efficiencies exceeding 26% and perovskite–silicon tandem efficiencies exceeding 33.9% as of 2024. Their appeal resides in the combination of a broadly tunable bandgap achieved through compositional engineering of the ABX₃ perovskite crystal structure, compatibility with low-temperature solution processing, and the potential for manufacturing costs substantially below those of silicon photovoltaics. However, the translation of laboratory-scale performance to commercially viable modules at industrial throughput remains the central challenge in the field. This review provides a comprehensive and critically organized account of PSC manufacturing, spanning device architectures and material requirements, scalable deposition and coating technologies, charge transport layer integration and interface engineering, process control and crystallization strategies, post-treatment methods, artificial intelligence and machine learning-assisted manufacturing, module fabrication and encapsulation, advanced tandem and flexible device configurations, green chemistry and circular lifecycle strategies, and the critical barriers to commercialization. The review concludes with a strategic assessment of the technological, regulatory, and economic requirements for PSC technology to transition from pilot-scale demonstration to utility-scale deployment. Full article

For large-scale floating offshore wind turbines, existing sensitivity studies have not fully addressed the combined effects of multiple uncertain input parameters on multiple output responses. Meanwhile, conventional Sobol indices quantify contribution magnitude but do not indicate effect direction. Based on the IEA 15 MW semi-submersible benchmark model, this study investigates the sensitivity of mooring tension and platform motion dynamic responses at a normal operating condition under power production. Integrated dynamic simulations were performed to generate response data. Eight uncertain parameters were considered, including the key mechanical and hydrodynamic coefficients of mooring lines as well as mass distribution and hydrodynamics-related key parameters for the platform. A polynomial chaos expansion surrogate model was used for the global sensitivity analysis, based on the Sobol index, Spearman coefficient, and a newly proposed modified Sobol index. The results indicate weak parameter interactions, with first-order Sobol indices dominating. The platform mass makes the largest contribution, with first-order Sobol indices approaching 1.0 for the mean tensions of all three mooring lines and 0.995 and 0.999 for the mean surge and heave displacements, respectively. The mooring line normal drag coefficient reaches a first-order Sobol index of 0.805 for the standard deviation of the upwind mooring line tension. The pitch response is influenced by multiple parameters. The Spearman coefficients confirmed the dominant parameters and identified their effect directions. By integrating variance contribution with effect direction, the modified Sobol index provides a more interpretable assessment of parameter effects. These findings can support parameter prioritization, mooring system design, and digital-twin model updating for floating offshore wind turbines. Full article

As the most critical component of organic solar cells (OSCs), the morphology of the active layer directly dictates the photovoltaic performance of the devices. Recent studies have demonstrated that tailoring the active layer morphology using solid additives is a facile and effective strategy to boost the performance of OSCs. Herein, we design and synthesize a novel solid additive, 5-bromobenzo[b]thiophene (5-BrBT), by introducing a bromine substituent onto the common benzothiophene unit. It is found that 5-BrBT optimizes the active layer formation process by effectively prolonging the nucleation time, which facilitates more controllable molecular nucleation and subsequent crystal growth during the pre-aggregation stage, leading to a more ideal donor-acceptor phase distribution. Furthermore, the binary PM6:L8-BO organic solar cells, fabricated with the incorporation of 5-BrBT, exhibit superior charge transport properties and exciton-generation efficiency, along with significantly suppressed charge recombination behaviors. Consequently, the 5-BrBT-treated binary PM6:L8-BO-based OSCs achieve an outstanding power conversion efficiency (PCE) of up to 19.44%, accompanied by simultaneous enhancements in short-circuit current density (J_SC) and fill factor (FF). This work provides a promising optimization strategy for achieving ideal nucleation behaviors during the bulk-heterojunction (BHJ) film processing via solid additives, which is expected to promote the development of more efficient OSCs. Full article