16168 research outputs found
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Marine inspired design of soil rippers using ship bulbous bow geometries: a cross-disciplinary approach with DEM simulation insights /
No full textOver the past decades, scientists have studied tillage and soil processing technologies based on the classical shapes of agricultural tools. Numerous studies highlight the importance of agricultural tool longevity in relation to abrasive wear resistance and draught force values. However, these studies are typically limited to the most common shapes and types of tools. This paper combines the insights gained from the marine industry's experience in the design of ship's bulbous bows with the challenges of designing soil rippers for agricultural machinery. New shape elements were developed based on the delta, oval, and nabla types of bulbous bows used in ships. Thirteen types of designed elements, along with the original shape, were tested virtually using the Discrete Element Method (DEM). The 3D-printed samples were then tested in a sand bin to measure draught force. DEM simulation parameters were validated by measuring the Static Angle of Repose (SAOR) of sand. The results of this study demonstrate that applying a bulbous bow-inspired shape to the soil ripper can reduce draught force by 7.1 %; however, in some cases, it can also increase the force by 4.1 % compared to the original shape. The values are giving statistically significant differences between the experimental measurements. To fully evaluate the application of these designed elements, further soil disturbance and wear analysis studies should be conducted in future research
Investigation and assessment of mechanical properties of co-extrusion with towpreg continuous carbon fiber reinforced thermoplastic composites manufactured using material extrusion /
No full textAdditive manufacturing (AM) is an advanced technique to fabricate a complex geometrical structure using polymer, metals, ceramics, and composite materials. Fused filament fabrication (FFF) is the most widely used extrusion-based AM technique to manufacture polymer and composite parts. Continuous carbon fiber (CCF) is a lightweight high-strength material that offers exceptional mechanical durability and performance when incorporated with polymers; it significantly enhances their performance. To print continuous fibers using the material extrusion technique, various methods have been adapted according to the AM technology. In this study, a self-developed co-extrusion with towpreg method was employed to fabricate the continuous fiber polymer composites in which both the materials polymer filament matrix and CCF reinforcement were inserted separately and extruded together through a single nozzle. Two important printing process parameters (layer height and line width) were considered with different ranges to investigate their influence on the mechanical properties (tensile, flexural, shear and compressive), air void volume, and fiber volume fraction. The results obtained demonstrate that both parameters have a significant impact on the properties and are mostly influenced by the layer height of the samples. The group of composite specimens with the layer height of 0.4 mm and line width of 1.0 mm showed the highest tensile, flexural, shear, and compressive strength of 372.68, 247.59, 42.83, and 184.19 MPa, respectively, with the minimum air void volume of 13.84%. Furthermore, the research outcomes highlight that the composites properties can be optimized by adjusting printing process parameters
Vitamins formed by microorganisms in fermented foods: effects on human vitamin status—a systematic narrative review /
No full textIntroduction: Vitamin deficiencies remain a global health issue, particularly among vulnerable populations. As microorganisms also produce vitamins, this has led to considering Fermented Foods (FF) as potential vehicles for improving vitamin intake. This systematic narrative review, which exclusively relies on human studies, aims to assess the extent to which the consumption of vitamin-rich FF contributes to the maintenance or enhancement of vitamin status in healthy or deficient populations. Methods: A comprehensive literature search (1970–2024) was conducted following the protocols of EFSA and the COST Action PIMENTO to identify interventional and observational studies investigating the influence of FF on biomarkers of vitamin status. Results: Findings confirm that certain microorganisms, including Bacillus subtilis, Propionibacterium freudenreichii, and some lactic acid bacteria, can increase the levels of vitamins K2, B2, B9, and B12 in FF. Evidence of bioavailability and physiological effects is reported. Notably, folate (vitamin B9) bioavailability was enhanced in some cases following the consumption of Camembert cheese naturally rich in folate, while vitamin K2 status was effectively improved in several studies on natto (fermented soy) and in one study on Jarlsberg cheese. However, evidence for other B vitamins (B1, B2, B3, B5, B6 and B12) is limited or inconsistent, and no human evidence exists for other vitamins. Vitamin bioavailability was found to be significantly influenced by the food matrix, fermentation type, microbial strain, and the form of the vitamin (vitamers). Effects may also be influenced by interactions with gut microbiota, including microbial vitamin synthesis and modulation of absorption. Discussion: Despite encouraging data, there is a lack of well-controlled, large-scale human studies to validate FF as a sustainable strategy to improve vitamin status. Future human studies research should investigate strain-specific effects, food matrix interactions, and long-term health outcomes
Overview of the use of co-creation tools for the design of sustainable buildings /
No full textThe transition toward sustainable building design increasingly emphasizes participatory approaches, where diverse stakeholders contribute to shaping solutions that balance environmental performance, social needs, and economic viability. This study provides an overview of the application of co-creation tools in the design process of sustainable buildings. Drawing on recent literature and practicebased examples, we examine how tools such as participatory design workshops, digital twins, virtual and augmented reality environments, and collaborative BIM platforms enable deeper engagement of users, designers, and decision-makers. The analysis identifies key benefits of co-creation, including improved user satisfaction, enhanced design adaptability, and stronger alignment with sustainability goals. It also explores challenges such as stakeholder coordination, data interoperability, and the need for capacity building in participatory methods. The study synthesizes findings across academic, professional, and policy domains to propose a typology of co-creation tools most relevant to sustainable architecture. The insights aim to inform both practitioners and researchers seeking to implement inclusive and effective design strategies in the built environment
Agar-based composites in sustainable energy storage: a comprehensive review /
No full textThe shift towards renewable resources has positioned agar, a natural seaweed polysaccharide, as a pivotal and sustainable material for developing next-generation energy storage technologies. This review highlights the transformative role of agar-based composites as a game-changing and eco-friendly platform for supercapacitors, batteries, and fuel cells. Moving beyond the traditional synthetic polymers, agar introduces a novel paradigm by leveraging its natural gelation, superior film-forming ability, and inherent ionic conductivity to create advanced electrolytes, binders, and matrices. The novelty of this field lies in the strategic fabrication of synergistic composites with polymers, metal oxides, and carbon materials, engineered through innovative techniques like electrospinning, solvent casting, crosslinking, 3D printing, and freeze-drying. We critically examine how these innovative composites are breaking new ground in enhancing device efficacy, flexibility, and thermal stability. Ultimately, this analysis not only consolidates the current landscape but also charts future pathways, positioning agar-based materials as a pivotal and sustainable solution for powering the future
Numerical study on elastic properties of natural fibres in multi-hybrid composites /
No full textThis study investigates the elastic properties of bio-epoxy composites reinforced with natural fibres (flax, hemp) and synthetic fibres (S-glass), with particular focus on the effect of the fibre volume fraction (VF) ranging from 10% to 70%. Three-dimensional representative volume element (RVE) models were developed for single-fibre, hybrid, and multi-fibre systems. The mean-field homogenisation (MF) approach, based on the Mori–Tanaka scheme, and finite element analysis (FEA) with periodic boundary conditions were employed to predict the effective elastic properties, including longitudinal, transverse, and shear moduli, as well as Poisson’s ratio. These numerical predictions were validated against analytical models, including the rule of mixtures, Chamis, and composite cylinder assemblage (CCA) methods. The results demonstrate that increasing the VF enhances longitudinal, transverse, and shear moduli while reducing Poisson’s ratio in natural fibre composites. The good agreement between numerical, semi-analytical, and analytical methods validates the 3D RVE models as useful tools for predicting the properties of multi-hybrid natural fibre composites, supporting their design for lightweight structural applications
Exploring the trade-off between materialism and pro-environmental behavior through the Lens of narcissism /
No full textThis study investigates the relationship between materialism and pro-environmental behavior, focusing on the moderating role of narcissism in the attitude–behavior gap. A mixed-method research design was employed, combining a preference-based conjoint experiment with psychometric scales including the Material Values Scale (MVS), Recurring Pro-Environmental Behavior Scale (PEB), and Narcissistic Admiration and Rivalry Questionnaire short scale (NARQ-S). A convenience sample of 71 participants evaluated pro-environmental behavior-related choices while also self-reporting their materialistic and pro-environmental values. Results revealed that profiles emphasizing low materialism and high pro-environmental attitudes were most preferred, supporting the hypothesized negative relationship between materialism and pro-environmental choices. The materialism–success dimension showed the strongest behavioral influence. However, narcissism did not significantly moderate the relationship between attitudes and behavior. These findings contribute to dual-attitude theory and impression-management literature by showing that materialists may endorse pro-environmental behavior when it supports social identity signaling. The results have implications for both marketers and policymakers in designing strategies that appeal to reputation-sensitive consumers
Screening of the carbazole-based phosphonic acids in perovskite solar cells: impact of the substitution pattern on device performance /
No full textSelf-assembled monolayers (SAMs) have become the standard hole-selective layer in high-efficiency p–i–n perovskite single-junction and multi-junction solar cells. Since there is limited information about the structure–property correlation, it is important to determine how structural changes in the molecule impact performance or enhance layer properties. In this work, nine different carbazole-based phosphonic acids with methyl, methoxy, and phenyl functional groups were compared to investigate the correlation between the chemical structure and device performance. The results reveal that phosphonic acids with different functional groups share some structure–property correlations and that substituents at 3,6 positions (3,6-Me-2PACz, 3,6-Ph-PACz, and 3,6-MeO-2PACz) of carbazole have higher perovskite single-junction device fill factors, which is one of the factors determining the performance of the device, than molecules with substituents in 2,7 or 4 positions. These findings were supported by transient surface photovoltage (trSPV) measurements. In addition, correlation between ionisation potential and fill factor suggests the threshold value, after which the fill factor is reduced, possibly due to the energy level misalignment. Additionally, the impact of different functional groups in the molecule was investigated with optical, thermal, and electrophysical methods by combining experimental and simulation methods. This work provides insightful knowledge that can contribute to further investigations and design of phosphonic acid-based materials