323,746 research outputs found
Olefin poly/oligomerizations by metal precatalysts bearing non–heterocyclic N–donor ligands
No full textAdvances in computational intelligence of polymer composite materials: machine learning assisted modeling, analysis and design
No full textThe superior multi-functional properties of polymer composites have made them an ideal choice for aerospace, automobile, marine, civil, and many other technologically demanding industries. The increasing demand of these composites calls for an extensive investigation of their physical, chemical and mechanical behavior under different exposure conditions. Machine learning (ML) has been recognized as a powerful predictive tool for data-driven multi-physical modeling, leading to unprecedented insights and exploration of the system properties beyond the capability of traditional computational and experimental analyses. Here we aim to abridge the findings of the large volume of relevant literature and highlight the broad spectrum potential of ML in applications like prediction, optimization, feature identification, uncertainty quantification, reliability and sensitivity analysis along with the framework of different ML algorithms concerning polymer composites. Challenges like the curse of dimensionality, overfitting, noise and mixed variable problems are discussed, including the latest advancements in ML that have the potential to be integrated in the field of polymer composites. Based on the extensive literature survey, a few recommendations on the exploitation of various ML algorithms for addressing different critical problems concerning polymer composites are provided along with insightful perspectives on the potential directions of future research
Exploiting hydroxyphenylbenzimidazol-based hybrids for metal-modulation in potential anti-Alzheimer ́s drugs
No full textnon previst
Investigation of thermo-mechanical and viscoelastic properties of 3D-printed Morinda citrifolia particle reinforced poly(lactic acid) composites
No full textThe current study focuses on the development of innovative bio-based filaments using new natural lignocellulosic particles obtained from the bark of the Morinda citrifolia L. plant as reinforcement. Polylactic acid (PLA 4043D) filaments with a diameter of 1.75 mm were produced by varying the volume fraction of M. citrifolia bark particles (MCBP) in three compositions (i.e., 0%, 3%, and 6%). These filaments were then used to print test specimens, which underwent quasi-static mechanical tests (i.e., tensile and flexural; thermal characterization, thermo-mechanical tests, and visco-elastic analysis). The experimental findings demonstrated a remarkable improvement in the tensile strength (i.e., +15%) when the PLA was reinforced with 6% in volume of lignocellulosic particles. Additionally, 3% MCBP and 6% MCBP composites showed substantial increases in flexural strength and modulus (i.e., +25% and +34%), respectively; in comparison to the neat matrix. Moreover, the 3D-printed composites exhibited significant enhancements in storage modulus, glass transition temperature, and structural stability at elevated temperatures. Hence, this work highlights the potential of the developed bio-based filaments as feedstock filament material, enabling the production of various customized lightweight products in the automotive and sports industries like cycling helmets, protective guards, knee guards, etc. Highlights: Innovative bio-based filaments are developed for FDM 3D printing. Morinda citrifolia bark particles (MCBPs) reduce warping risk in PLA printing. The hot crystallization enthalpy of PLA increases with the addition of MCBP. 6% MCBP-PLA exhibits the best mechanical performances. MCBP reinforcement reduces the thermal expansion of PLA
LEMONGRASS PLANT LEAF AND CULM AS POTENTIAL SOURCES OF REINFORCEMENT FOR BIO-COMPOSITES
No full textA possible source of natural reinforcement for bio-composites can be represented by lemongrass plant (Cymbopogon flexuosus), a clumped and perennial grass which belongs to the Poaceae family. This plant is extensively used for several applications such as pharmacology, food preservation and cosmetics but, to the best of our knowledge, few papers were published on its use as source for reinforcement of composites and no one article was focused on the comparison between lemongrass leaves and culms as potential source of natural reinforcement. To this aim, a preliminary investigation on leaf and culm fibers was carried out to compare their physical and chemical features as well as their tensile properties. Furthermore, bio-composites based on a biodegradable starch-derived matrix (MaterBi®) and lemongrass leaf and culm particles were manufactured via extrusion and compression molding. For both fillers, two compositions (i.e., 10% and 20 wt.%) were investigated in terms of morphological and mechanical properties
Basalt powder based thermoset and thermoplastic composites for lightweight applications
No full textThe continuous raise of environmental issues by the polymer products has led to the use of eco-friendly basalt as a reinforcement for the composites fabrication. Basalt reinforcement has attractive qualities such as non-toxicity, ease of processing steps, economical, less harmful, and excellent thermal, and mechanical properties. Basalt loading into different polymer matrices is indeed a comparably novel concept that may offer some very intriguing views, which have not yet been fully explored. The ability of mineral fillers such as basalt powder to reduce the polymer portion in polymer goods by retaining their original characteristics hand out to the establishment of a pollution-free ecosystem and the stabilizing of ecological issues. In this context, the current research aims to manufacture and characterize thermoset (i.e., synthetic epoxy, bio-epoxy, unsaturated polyester, and vinyl ester) and thermoplastic (i.e., polylactic acid, bio-based polypropylene, and bio-based high density polyethylene) composites reinforced with the same weight content (i.e., 30%) of basalt powder. These composites were employed for physical, mechanical, wettability (contact angle analysis), morphological, and water absorption investigations. Moreover, basalt powder was subjected to elemental analysis (Energy dispersive X-ray), particle dimensional analysis, and morphological (Scanning Electron Microscopy) observations. The experimental results revealed that the tensile, flexural, and impact strength characteristics of composites were slightly reduced in comparison to neat polymers because of higher reinforcement. Besides, the tensile modulus, flexural modulus, and hardness values were gradually improved due to the filler effect. The increased water absorption is mainly caused by the voids inside of the composites, which create the quintessential environment for moisture to seep into the interface. Differential scanning calorimetry analysis reveals that the filler has successfully maintained the chain relaxation with the reduction of molecular movement and achieved stability as equivalent to a 100% polymer system, despite the incorporation of basalt by reducing the 30 wt% polymers. Except for synthetic epoxy composite, the remaining polymer composites have shown enhanced thermal conductivity values than neat polymers. However, the obtained findings can be considered satisfactory for prospective applications concerning lightness and environmental friendliness
Diffusive author(s), cohesive author: Analysis of S/N (1994)
No full textThis study indicates the ways in which various aspects of the author(s) are brought forth in Dumb type’s performance art, the S/N production. Previous research has suggested a non-hierarchical organization of Dumb type and the absence of a “privileged author” in Dumb type’s collaborative work, S/N. However, the results that I have investigated from member’s interviews on the creative process of S/N along with my analysis of the recorded images of S/N, indicate a different aspect of the author(s). First, S/N was created through, so to speak, the collective ideas of the members of Dumb type. Further, S/N has at least nine quotations from previous performances, installations, and printed writings, besides the work-in-progress technique. Explicating one of the “author functions” as given by Michel Foucault, each text has plural subjects of the author. However, it has been revealed from members’ interviews that Teiji Furuhashi had a decision-making role in selecting the members’ ideas within the performance. Since then, S/N has had plural subjects of creation; however, Furuhashi is one of the subjects of creation along with the “privileged author.” S/N has plural authors (diffusive authors) yet at the same time, it has a “privileged author,” Teiji Furuhashi (cohesive author)
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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