jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Martha D. Vallejo | Manuel Loaiza | Gage Pankey | Vanessa Restrepo
Source:  (article, 2024-09-09)
Field: Materials Science — Polymers and Plastics

Impact of Fabrication Process Variations on Epoxy Shape Memory Polymer Mechanical Properties Across Temperature Gradients Abstract Shape Memory Polymers (SMPs) are versatile polymeric materials that are able to undergo reversible shape changes triggered by external stimuli like temperature, electric current, UV light, and magnetic fields. Epoxy Shape Memory Polymers (ESMPs), a subset of SMPs, are notably influenced by compositional changes. While previous studies focused on the response of thermal and mechanical properties based on composition changes, understanding how the fabrication process affects mechanical performance remains limited. This research addresses the mentioned gap, by systematically evaluating the mechanical properties at different temperatures, and particularly considering variations in time and temperature during the curing process of the ESMP. Using the Taguchi method, an L9 orthogonal array design was employed with a signal-to-noise quality characteristic analysis. Ninety ESMP samples with consistent composition but varying curing and post-curing parameters were produced. ESMP molar ratio was chosen for a glass transition temperature of 36°C, enabling sample programming by body temperature. Tensile testing at different environmental conditions revealed significant impacts of fabrication process on the ESMP mechanical behavior. Longer curing and post-curing times and higher temperatures increased stiffness and strength, while shorter processing times at lower temperatures decreased these properties. Maintaining the manufacturing parameters and testing the samples at higher temperature reduced the stiffness, strength, and strain at failure. These findings facilitate customized fabrication for applications requiring variable properties, particularly in active mechanical interfaces responding to external stimuli. Fabrication ; Epoxy ; Materials science ; Polymer ; Process (computing) ; Shape-memory polymer ; Composite material ; Computer science Polymer composites and self-healing
Authors: Prosper Mensah | Francis Kofi Bih | Emmanuel Okumi-Andoh
Source: Global Journal of Engineering and Technology Advances (article, 2024-02-20)
Field: Materials Science — Polymers and Plastics

Properties of elephant grass made particleboards: Influence of a hardener The objective of the study was to assess the performance of one of the most abundant raw materials on Earth – the Elephant grass, for the production of particleboard bonded using cassava starch blended with Aluminium sulphate (Al2(SO4)3) as hardener. The physical, mechanical and decay properties of the manufactured particleboards were analyzed and compared with EN 312-2 (2005) and ANSI A208.1 (1999) standards for particleboards. The characterization also included thermogravimetric analysis and scanning electron micrographs. The results showed that the interaction of the Aluminium sulphate (Al2(SO4)3) hardener and the adhesives in the particleboard significantly affected the physical, mechanical, thermogravimetric and the decay properties of the manufactured particleboards. The particleboards with only Cassava starch as adhesive recorded 11.14% and 24.84% for 24-hour water absorption and thickness swelling respectively. However, with the blending of the adhesive with Al2(SO4)3, Cassava starch recorded 20.51% better for 24-hour WA and 35.62% better for 24-hour TS. Urea formaldehyde as an adhesive blended with the hardener also recorded better performance in the 24-hour dimensional stability property assessment. Similar trends of enhanced property performance were observed for the intended properties tested when Al2(SO4)3 is added to each adhesive. Static bending, hardness, internal bond strength, dimensional stability, thermogravimetric and decay resistance properties of the test particleboard improved with the addition of Al2(SO4)3. Environmental science ; Materials science ; Composite material Natural Fiber Reinforced Composites ; Soil Mechanics and Vehicle Dynamics ; Agricultural Engineering and Mechanization
Authors: Alaa Al-Shaer | Nancy R. Forde
Source: bioRxiv (Cold Spring Harbor Laboratory) (preprint, 2024-10-03)
Field: Materials Science — Biomaterials

Decoding Collagen's Thermally Induced Unfolding and Refolding Pathways Collagen has been evolutionarily selected as the preferred building block of extracellular structures. Despite inherent thermal instability of individual proteins at body temperature, collagen manages to assemble into higher-order structures that provide mechanical support to tissues. Sequence features that enhance collagen stability have been deduced largely from studies of collagen-mimetic peptides, as the large sizes of collagens have precluded high-resolution studies of their structure. Thus, there is a need for new methods to analyze the structure and mechanics of native collagen proteins. In this study, we used AFM imaging to investigate the temperature response of collagen types I, III and particularly IV. We observed a time-dependent loss of folded structures upon exposure to body temperature, with structural destabilization along the collagenous domain reflected by a shorter overall contour length. We characterized the sequence-dependent bending stiffness profile of collagen IV as a function of temperature and identified a putative initiation site for thermally induced unfolding. Interchain disulfide bonds in collagen IV were shown to enhance thermal stability and serve as the primary nucleation sites for in vitro refolding. In contrast to the canonical C-to-N terminal folding direction, we found an interchain cystine knot to enable folding in the opposite direction. Multiple sequence alignments revealed that this cystine knot is evolutionarily conserved across metazoan phyla, highlighting its significance in the stabilization of early collagen IV structures. Our findings provide mechanistic insights into the unfolding and refolding pathway of collagen IV, providing valuable insight into how its heterogeneous sequence influences stability and mechanics. Decoding methods ; Chemistry ; Biophysics ; Computer science ; Biology ; Telecommunications Collagen: Extraction and Characterization ; Cell Adhesion Molecules Research
Authors: Florian D’Ambra | V. Faucheux | Emmanuel Nicolas | Thibault Cantat | Gérard Gebel | Parviz Hajiyev
Source: ChemRxiv (preprint, 2024-04-26)
Field: Chemistry — Organic Chemistry

Direct enthalpy measurement for hydrogenation of liquid organic hydrogen carriers by Differential Scanning Calorimetry under H2 pressure In this contribution, we report the hydrogenation enthalpy direct measurement of well-studied Liquid Organic Hydrogen Carriers (LOHC) (Dibenzyltoluene, N-Ethylcarbazole, 2-Octanone) and of a new LOHC (Acetophenone) by differential scanning calorimetry (DSC) under H2 pressure. The obtained hydrogenation enthalpies showed good correspondence with DFT predictions and the literature. Moreover, multistep hydrogenation processes were investigated, evidencing that transfer hydrogenation occurred during the reaction. The study of bifunctional LOHC such as acetophenone and its derivatives showcased the potential of direct enthalpy measurement for rapid LOHC screening. Besides, a DFT correction factor for this specific bifunctional LOHC class was experimentally obtained, enabling more precise DFT predictions for similar systems. Kinetic parameters such as the activation energies for the catalytic Ru/Al2O3 system were also determined to be in the 45-60 kJ/mol range, compatible with the H2 adsorption on the Ru surface. The detrimental effect of steric hinderance was also observed. Finally, the reaction order in H2 was experimentally estimated to ~1 for all of the studied LOHCs. Bifunctional ; Acetophenone ; Enthalpy ; Differential scanning calorimetry ; Chemistry ; Steric effects ; Catalysis ; Hydrogen ; Physical chemistry ; Organic chemistry ; Thermodynamics Chemical Thermodynamics and Molecular Structure ; Thermal and Kinetic Analysis ; Thermodynamic properties of mixtures
Authors: Sümeyye Aykut | Nida Ük | İbrahim Yağız Coşkun | Sultan Şahin Keskin | Ilgın Nar | Levent Trabzon | Caner Ünlü
Source: Photosynthesis Research (article, 2024-02-26)
Field: Materials Science — Materials Chemistry

Modulating spectral response of raw photosynthetic pigments via ternary cadmium chalcogenide quantum dots: simultaneous enhancement at green spectrum and inhibition at UV region Photosynthesis relies on the absorption of sunlight by photosynthetic pigments (PPs) such as chlorophylls and carotenoids. While these pigments are outstanding at harvesting light, their natural structure restricts their ability to harvest light at specific wavelengths. In this study, Oleic acid-capped CdSeS and CdTeS ternary quantum dots (QDs) were synthesized using a novel two-phase synthesis method. Then, these QDs were used to interact with raw PPs, a mixture of chlorophylls and carotenoids isolated from spinach. Our findings revealed the following: (1) Interacting QDs with raw PPs effectively inhibited the chlorophyll fluorescence of the pigments upon excitation in UV light region (250-400 nm) without causing any damage to their structure. (2) By forming an interaction with QDs, the chlorophyll fluorescence of raw PPs could be induced through excitation with green-light spectrum. (3) The composition of the QDs played a fundamental role in their interaction with PPs. Our study demonstrated that the photophysical properties of isolated PPs could be modified by using cadmium-based QDs by preserving the structure of the pigments themselves. Fluorescence ; Photosynthesis ; Pigment ; Ternary operation ; Photochemistry ; Carotenoid ; Quantum dot ; Chlorophyll ; Chemistry ; Chlorophyll a ; Cadmium ; Materials science ; Spinach ; Optoelectronics ; Organic chemistry ; Food science ; Optics ; Biochemistry ; Physics Quantum Dots Synthesis And Properties ; Chalcogenide Semiconductor Thin Films ; Nanocluster Synthesis and Applications
Authors: Yue Liu
Source: Highlights in Science Engineering and Technology (article, 2024-12-24)
Field: Materials Science — Polymers and Plastics

Advance in Shape Memory Polymers for Aerospace Applications As humanity's exploration of cosmic space becomes more and more in-depth, aerospace technology, as a critical cornerstone supporting this endeavor, is constantly facing new challenges and opportunities. Aerospace engineering has extremely stringent requirements for materials, which require high strength and toughness to withstand extreme environmental conditions, such as high temperature, low temperature, high radiation, etc., and meet the complex needs of lightweight, high reliability, and multi-functional integration. Traditional materials often face many limitations in meeting these requirements, and the emergence of shape memory polymers (SMPs) has provided new ideas and possibilities for the design and application of aerospace materials. As an emerging class of intelligent materials, SMPs, due to their unique shape memory effect, lightweight and high strength, good designability, and other characteristics have gradually demonstrated excellent application potential in several aspects of the aerospace field. Application potential in many aspects of the aerospace field. Based on this, this paper first explains the shape memory effect (SME). Then, SMPs under different actuation conditions are explored, including light, heat, electricity, and magnetic field stimulation conditions. Finally, the paper highlights the application of SMPs in wing deformation structures, space deployable structures, thermal protection systems, etc. This will provide new solutions for the lightweight and multifunctional design of spacecraft. Aerospace ; Spacecraft ; Aerospace engineering ; Aerospace materials ; Shape-memory polymer ; Mechanical engineering ; Computer science ; Systems engineering ; Materials science ; Engineering ; Shape-memory alloy Polymer composites and self-healing
Authors: Florent Mohimont | Jutta Rieger | François Stoffelbach
Source: Macromolecular Rapid Communications (article, 2024-06-09)
Field: Chemistry — Organic Chemistry

Synthesis of New Glycine‐Based Polymers and their Thermoresponsive Behavior in Water In this work, new glycine-derived polymers are developed that exhibit thermoresponsive properties in water. Therefore, a series of monomers containing one, two, or three amide functional groups and one terminal cyanomethyl group is synthesized. The resulting homopolymers, obtained by free radical polymerization (FRP) and reversible addition fragmentation chain transfer (RAFT) polymerization, display a sharp and reversible upper critical solution temperature (UCST)-type phase transition in water. Additionally, it is shown that the cloud point (T<sub>CP</sub>) can be adjusted over more than 60 °C by the number of glycyl groups present in the monomer structure and by the polymer's molar mass. These novel thermoresponsive polymers based on cyanomethylglycinamide enrich the range of nonionic UCST polymers and are promising to find applications in various fields. Upper critical solution temperature ; Polymer ; Monomer ; Polymer chemistry ; Molar mass ; Thermoresponsive polymers in chromatography ; Materials science ; Polymerization ; Chain transfer ; Radical polymerization ; Cloud point ; Raft ; Phase transition ; Chemical engineering ; Reversible addition−fragmentation chain-transfer polymerization ; Lower critical solution temperature ; Chemistry ; Phase (matter) ; Copolymer ; Aqueous solution ; Organic chemistry ; Thermodynamics ; Composite material Advanced Polymer Synthesis and Characterization ; Covalent Organic Framework Applications ; Synthesis and properties of polymers
Authors: Domenic Pace | Reece Crocker | William J. Kendrick | Bolong Zhang | Wallace W. H. Wong | Binh Khanh | Timothy W. Schmidt | Thành Vinh Nguyễn
Source: ChemRxiv (preprint, 2024-04-03)
Field: Materials Science — Materials Chemistry

Development of a Novel Solid State Organic Fluorophore: Excited-State Aromatization-Induced Structural Planarization Solid-state emission is pivotal for the functionality of organic compounds in opto-electronic applications. Yet, tailoring the emission characteristics of existing solid-state emissive organic frameworks is a challenging task, primarily due to their intricate structure-activity interplay. In this study, we introduce an innovative family of solid-state luminogens, centered around the dibenzosuberenylidene core. These luminogens are characterized by a remarkable excited-state aromatization-induced structural planarization (ESAISP) behaviour. This unique feature allows for the modulation of their fluorescence properties, including color and intensity, through simple structural alterations, opening new avenues in the development of organic advanced functional materials. Chemical-mechanical planarization ; Fluorophore ; Aromatization ; Solid-state ; Excited state ; Fluorescence ; Materials science ; Nanotechnology ; Optoelectronics ; Chemistry ; Organic chemistry ; Atomic physics ; Physical chemistry ; Physics ; Layer (electronics) ; Optics Luminescence and Fluorescent Materials ; Silicone and Siloxane Chemistry ; Porphyrin and Phthalocyanine Chemistry
Authors: Volodymyr V. Voloshchuk | Sergey P. Ivonin
Source: Journal of organic and pharmaceutical chemistry (article, 2024-06-19)
Field: Chemistry — Organic Chemistry

Recent Advances in the Synthesis and Biological Activity of Pyrrolo[2,3-c]pyridines Pyrrolo[2,3-c]pyridines (6-azaindoles) are the most promising nitrogen-containing heterocyclic compounds in the field of drug development. Exhibiting extraordinary versatility as pharmacophores, they are widely used in the development of kinase inhibitors, antiproliferative agents, and as potential therapeutic agents for the treatment of various diseases, including cancer and Alzheimer’s disease. A large number of works focusing on new methods and approaches in the synthesis of 6-azaindoes, as well as on the study of their biological activity, have been published worldwide. In our review, we tried to classify all currently known strategies for the construction of the 6-azaindole core, which were published within the last 15 years, the chemical diversity of the derivatives obtained, and their therapeutic potential in the context of medicinal chemistry. We hope that this work will generalize and facilitate the understanding of the strategy for the synthesis of pyrrolo[2,3-c]pyridines, as well as help scientists in their further research in the direction of 6-azaindoles. Biological activity ; Chemistry ; Combinatorial chemistry ; Stereochemistry ; Biochemistry ; In vitro Synthesis and Characterization of Pyrroles ; Radical Photochemical Reactions ; Catalytic C–H Functionalization Methods
Authors: Gerard Martí | Marc Serra-Peralta | Gemma Rius
Source: Physics of Fluids (article, 2024-12-01)
Field: Materials Science — Surfaces, Coatings and Films

Rational design of static wetting on roughness-engineered heterogeneous surfaces Surface roughness and chemical composition are crucial in controlling the static wetting properties of surfaces. Here, conventional surface structuring methods used in Si microfabrication are used as a reference to analyze the impact of precisely engineered surface roughness. The static wettability of rough chemically heterogeneous surfaces is experimentally studied through contact angle measurements and compared against computational simulations to categorize the wetting behavior of water droplets. Heterogeneous samples are observed to already show significant dependence on the surface fraction covered by each material. Furthermore, owing to the presence of a resist layer on top of the Si pillars, intermediate states between the Wenzel (W) and Cassie–Baxter (CB) models are observed. Consistent with these models, we find that local chemical modifications of microstructured surfaces are crucial for controlling their surface wettability properties. Additionally, a comparison of equivalent microstructures made of Si or polydimethylsiloxane (PDMS) reveals the quantitative impact of the hydrophilic/hydrophobic nature of the material on the evolution of the wetting properties with increasing roughness factors. While Si surfaces behave according to the W model, PDMS surfaces show intermediate wetting states at significantly lower roughness levels. Bubbles trapped beneath water droplets demonstrate the existence of intermediate states that cannot be defined by either the W or CB models. By combining experimental results with finite element simulations, we not only demonstrate wettability control through specific roughness and chemical modifications but also provide insight into how these parameters interact to accurately predict and adjust static wetting properties. Physics ; Wetting ; Surface roughness ; Surface finish ; Mechanics ; Mechanical engineering ; Thermodynamics Surface Modification and Superhydrophobicity ; Adhesion, Friction, and Surface Interactions ; Additive Manufacturing and 3D Printing Technologies
Authors: Dienifer F. L. Horsth | Julia de O. Primo | Fauze Jacó Anaissi | Polona Umek | Carla Bittencourt
Source: Colorants (article, 2024-10-11)
Field: Chemistry — Inorganic Chemistry

Sustainable Near-Infrared Reflective Blue Pigments: Recycled Aluminum from Can Seals for Cobalt Aluminates in Cool Coatings Inorganic cool pigments are widely used as cooling agents in residential coatings due to their ability to achieve near-infrared reflectance. These coatings can be designed to exhibit a variety of colors independent of their reflectivity and absorption properties. Recent studies have highlighted the development of novel near-infrared (NIR) blue pigments, with an increasing emphasis on environmentally sustainable options that demonstrate high NIR reflectivity. This trend highlights the importance of creating novel and eco-friendly NIR reflective blue pigments. This study presents the synthesis of cobalt aluminates with varying concentrations of coloring ions (Co2+), achieved through the recycling of aluminum can seals via chemical precipitation. The formation of the spinel phase was confirmed through X-ray diffraction (XRD), and a colorimetric analysis was performed in the CIEL*a*b* color space. The synthesized pigments exhibited high near-infrared solar reflectance, with R% values ranging from 34 to 54%, indicating their potential as energy-efficient color pigments for use in coatings. Cobalt ; Pigment ; Aluminium ; Infrared ; Materials science ; Metallurgy ; Blue light ; Chemistry ; Optoelectronics ; Optics ; Organic chemistry Pigment Synthesis and Properties ; Cultural Heritage Materials Analysis
Authors: Nataphon Phupewkeaw | Pongdhorn Sae‐Oui | Chakrit Sirisinha‬
Source: Preprints.org (preprint, 2024-06-12)
Field: Materials Science — Polymers and Plastics

Optimizing Processing Parameters for NR/EBC Thermoplastic Vulcanizates: A Comprehensive Full Factorial Design of Experiments (DOE) Strategy This research explores the development of thermoplastic vulcanizate (TPV) blends derived from natural rubber (NR) and ethylene-butene copolymer (EBC) using a specific blend ratio and melt mixing technique. A comprehensive full factorial design of experiments (DOE) methodology is employed to optimize the processing parameters. TPVs are produced through dynamic vulcanization, combining rubber crosslinking and melt blending within a thermoplastic matrix under high temperatures and shear. The physico-mechanical properties of these TPVs are then analyzed. The objective is to enhance the mechanical performance by assessing the influence of blend ratio, mixing temperature, rotor speed, and mixing time on crucial properties, including tensile strength, elongation at break, compression set, tear strength, and hardness. Analysis of variance (ANOVA) identifies the optimal processing conditions that significantly improve material performance. Validation is achieved through atomic force microscopy (AFM), confirming the phase-separated structure and thus a success of dynamic vulcanization. Rubber process analyzer (RPA) and dynamic mechanical analyzer (DMA) assessments provide insights into the viscoelastic behavior and dynamic mechanical responses. Deconvolution analysis of temperature-dependent tanδ peaks reveals intricate microstructural interactions influencing the glass transition temperature (Tg). The optimized TPVs exhibit enhanced stiffness and effective energy dissipation capabilities across a wide temperature range, making them suitable for applications demanding thermal and mechanical load resistance. This study underscores the pivotal role of precise processing control in tailoring the properties of NR/EBC TPVs for specialized industrial uses. It highlights the indispensable contribution of the DOE methodology to TPV optimization, advancing material science and engineering, particularly for industries requiring robust and flexible materials. Materials science ; Thermoplastic ; Composite material ; Vulcanization ; Ultimate tensile strength ; Natural rubber ; Dynamic mechanical analysis ; Factorial experiment ; Tear resistance ; Design of experiments ; Compatibilization ; Fractional factorial design ; Polymer blend ; Polymer ; Computer science ; Copolymer Polymer Nanocomposites and Properties ; Polymer crystallization and properties ; Rheology and Fluid Dynamics Studies