jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Julian Hniopek | Josefine Meurer | Stefan Zechel | Michael Schmitt | Martin D. Hager | Jürgen Popp
Source: Chemical Science (article, 2023-01-01)
Field: Materials Science — Polymers and Plastics

Molecular <i>in situ</i> monitoring of the pH-triggered response in adaptive polymers by two-dimensional Raman micro-correlation-spectroscopy Stimuli-responsive polymers can switch specific physical properties in response to a change of the environmental conditions. This behavior offers unique advantages in applications where adaptive materials are needed. To tune the properties of stimuli-responsive polymers, a detailed understanding of the relationship between the applied stimulus and changes in molecular structure as well as the relationship between the latter and macroscopic properties is required, which until now has required laborious methods. Here, we present a straightforward way to investigate the progressing trigger, the change of the chemical composition of the polymer and the macroscopic properties simultaneously. Thereby, the response behavior of the reversible polymer is studied <i>in situ</i> with molecular sensitivity and spatial as well as temporal resolution utilizing Raman micro-spectroscopy. Combined with two-dimensional correlation analysis (2DCOS), this method reveals the stimuli-response on a molecular level and determines the sequence of changes and the diffusion rate inside the polymer. Due to the label-free and non-invasive approach, it is furthermore possible to combine this method with the investigation of macroscopic properties revealing the response of the polymer to the external stimulus on both the molecular and the macroscopic level. Polymer ; Raman spectroscopy ; In situ ; Biological system ; Chemical physics ; Materials science ; Molecular dynamics ; Temporal resolution ; Nanotechnology ; Chemistry ; Computational chemistry ; Physics ; Organic chemistry ; Optics Conducting polymers and applications ; Analytical Chemistry and Sensors ; Advanced Sensor and Energy Harvesting Materials
Authors: Caroline J. Aschendorf | Mawuli Degbevi | Keaton V. Prather | Emily Y. Tsui
Source: Chemical Science (article, 2023-01-01)
Field: Materials Science — Materials Chemistry

EPR spin trapping of nucleophilic and radical reactions at colloidal metal chalcogenide quantum dot surfaces The participation of the surfaces of colloidal semiconductor nanocrystal quantum dots (QDs) in QD-mediated photocatalytic reactions is an important factor that distinguishes QDs from other photosensitizers (<i>e.g.</i> transition metal complexes or organic dyes). Here, we probe nucleophilic and radical reactivity of surface sulfides and selenides of metal chalcogenide (CdSe, CdS, ZnSe, and PbS) QDs using chemical reactions and NMR spectroscopy. Additionally, the high sensitivity of EPR spectroscopy is adapted to study these surface-centered reactions through the use of spin traps like 5,5-dimethyl-1-pyrroline-<i>N</i>-oxide (DMPO) under photoexcitation and thermal conditions. We demonstrate that DMPO likely adds to CdSe QD surfaces under thermal conditions by a nucleophilic mechanism in which the surface chalcogenides add to the double bond, followed by further oxidation of the surface-bound product. In contrast, CdS QDs more readily form surface sulfur-centered radicals that can perform reactions including alkene isomerization. These results indicate that QD surfaces should be an important consideration for the design of photocatalysis beyond simply tuning QD semiconductor band gaps. Chalcogenide ; Quantum dot ; Electron paramagnetic resonance ; Trapping ; Nucleophile ; Metal ; Spin (aerodynamics) ; Spin trapping ; Chemistry ; Photochemistry ; Colloid ; Materials science ; Nanotechnology ; Physics ; Physical chemistry ; Nuclear magnetic resonance ; Catalysis ; Organic chemistry Quantum Dots Synthesis And Properties ; Electron Spin Resonance Studies ; Chalcogenide Semiconductor Thin Films
Authors: Maria А. Chernomorova | Marina S. Myakinina | Vladimir А. Zhinzhilo | Igor Е. Uflyand
Source: Polymers (article, 2023-01-20)
Field: Chemistry — Inorganic Chemistry

Analytical Determination of Cephalosporin Antibiotics Using Coordination Polymer Based on Cobalt Terephthalate as a Sorbent In this work, a coordination polymer based on cobalt terephthalate was obtained and characterized by elemental analysis, infrared spectroscopy, X-ray diffraction analysis, and scanning electron microscopy. The coordination polymer was tested as a sorbent for the solid-phase extraction of cephalosporin antibiotics, including ceftriaxone, cefotaxime, and cefazolin, from aqueous solutions. The coordination polymer had a high adsorption capacity (520.0 mg/g). Antibiotics adsorption followed pseudo-second order kinetic model and the Freundlich isotherm model. The calculated thermodynamic parameters indicate a spontaneous process. The resulting coordination polymer has good stability and reusability. The possibility of separating the studied cephalosporins on a chromatographic column filled with a coordination polymer was shown. This work opens great prospects for the development and application of a coordination polymer based on cobalt terephthalate for the removal of cephalosporins from ambient water. Freundlich equation ; Materials science ; Polymer ; Sorbent ; Cobalt ; Adsorption ; Coordination polymer ; Chemical engineering ; Aqueous solution ; Chemistry ; Organic chemistry ; Composite material ; Metallurgy Metal-Organic Frameworks: Synthesis and Applications ; Chemical Synthesis and Characterization ; Analytical chemistry methods development
Authors: Veronika Hovanová | Andrej Hovan | Gabriel Žoldák | Erik Sedlák | Martin Humeník
Source: Protein Science (article, 2023-07-07)
Field: Materials Science — Biomaterials

Global analysis of kinetics reveals the role of secondary nucleation in recombinant spider silk self‐assembly Recombinant spider silk proteins can be prepared in scalable fermentation processes and have been proven as sources of biomaterials for biomedical and technical applications. Nanofibrils, formed through the self-assembly of these proteins, possess unique structural and mechanical properties, serving as fundamental building blocks for the fabrication of micro- and nanostructured scaffolds. Despite significant progress in utilizing nanofibrils-based morphologies of recombinant spider silk proteins, a comprehensive understanding of the molecular mechanisms of nanofibrils self-assembly remains a challenge. Here, a detailed kinetic study of nanofibril formation from a recombinant spider silk protein eADF4(C16) in dependence on the protein concentration, seeding, and temperature is provided. For the global fitting of kinetic data obtained during the fibril formation, we utilized the online platform AmyloFit. Evaluation of the data revealed that the self-assembly mechanism of recombinant spider silk is dominated by secondary nucleation. Thermodynamic analyses show that both primary and secondary nucleations, as well as the elongation step of the eADF4(C16), are endothermic processes. Spider silk ; SILK ; Nucleation ; Spider ; Nanotechnology ; Recombinant DNA ; Self-assembly ; Kinetics ; Materials science ; Chemistry ; Biophysics ; Biology ; Biochemistry ; Composite material ; Organic chemistry Silk-based biomaterials and applications ; Biochemical and Structural Characterization ; Antimicrobial Peptides and Activities
Authors: Shibin Chen | Cuiting Yang | Xiaoying Zhou | Guang Miao | Hao Yu | Jing Xiao
Source: AIChE Journal (article, 2023-09-21)
Field: Materials Science — Materials Chemistry

Liquid‐phase selective adsorption of xylene isomers in ultramicroporous carbon spheres Abstract The objective of this work is to investigate adsorption separation of liquid‐phase xylene isomers using ultramicroporous carbon spheres. The synthesized glucose‐based adsorbent (UMC‐xyl) enabled the challenging separation of liquid‐phase p ‐xylene/ m ‐xylene with an adsorption selectivity of 53 as well as p ‐xylene uptake of 91mg/g, outperforming a series of commercial adsorbents including the industrial benchmark KBaX. The micropore diffusion model was used to give the best fit to the adsorption kinetics of UMC‐xyl with a rate achieved higher than KBaX. The xylene isomer separation was facilitated by the narrow ultramicropore size distributed at 5.8–6.8 Å in UMC‐xyl via a synergistic kinetic and size‐sieving separation mechanism. Breakthrough experiments confirmed the effectiveness of UMC‐xyl in the dynamic selective separation of p ‐xylene from xylene isomers, together with superior multiple‐cycle eluent regenerability under the synergistic effects of the “like‐dissolve‐like” principle and π–π interaction. The work opens a new direction of using porous carbon adsorbents for continuous liquid‐phase separation of challenging hydrocarbon isomers. Adsorption ; Chemistry ; p-Xylene ; Selectivity ; Xylene ; Carbon fibers ; Phase (matter) ; Hydrocarbon ; Chemical engineering ; Diffusion ; Toluene ; Microporous material ; Chromatography ; Organic chemistry ; Materials science ; Thermodynamics ; Catalysis Mesoporous Materials and Catalysis ; Metal-Organic Frameworks: Synthesis and Applications ; Supercapacitor Materials and Fabrication
Authors: V. Dhanya | N. Rajesh
Source: RSC Advances (article, 2023-01-01)
Field: Materials Science — Materials Chemistry

A cradle to cradle approach towards remediation of uranium from water using carbonized arecanut husk fiber Sustainable materials for remediation of pollutants from water is the need of the hour. In this study two carbonaceous adsorbents prepared through hydrothermal carbonisation and pyrolysis from arecanut husk fiber, an agricultural waste material were used for the adsorption of uranium from water. Batch adsorption data as interpreted using the Langmuir model showed adsorption capacities of 250 mg g<sup>-1</sup> and 200 mg g<sup>-1</sup> respectively at pH 6 for the hydrochar (AHFC) and the pyrochar (AHFT) exceeding that reported for most of the unmodified biochars. The adsorption followed pseudo-second order kinetics and was exothermic in nature. The high selectivity and excellent removal efficiencies on application to environmental ground water samples and good regeneration capacity make these sorbents promising eco-friendly materials for uranium remediation from water. Husk ; Carbonization ; Environmental remediation ; Uranium ; Fiber ; Environmental science ; Materials science ; Pulp and paper industry ; Composite material ; Metallurgy ; Engineering ; Botany ; Biology ; Contamination ; Ecology Graphite, nuclear technology, radiation studies ; Radioactive element chemistry and processing ; Extraction and Separation Processes
Authors: Claudia Leimhofer | Alexander Hammer | Wolfgang Roland | Saskia Dollberger | Timo Ehrmann | Gérald Berger | Sabine Hild
Source: Journal of Applied Polymer Science (article, 2023-09-11)
Field: Materials Science — Polymers and Plastics

Investigation of interdiffusion between compatible polymers under static and co‐extrusion processing conditions Abstract When two compatible polymer melts are brought into contact, a diffuse interphase is formed that governs the adhesion between them. The degree of interdiffusion is defined mainly by the processing conditions and the physico‐chemical properties of the materials. Despite the great industrial relevance of co‐extrusion in manufacturing multilayer structures, little research has dealt with interdiffusion under these processing conditions, where polymer‐polymer interfaces are subject to shear load. In this work, procedures for investigating interdiffusion both under static and real co‐extrusion flow conditions were developed. Using various grades of poly(methyl methacrylate) and styrene‐ co ‐acrylonitrile copolymer, we studied both theoretically and experimentally the effects of interfacial contact time, temperature, material compatibility, and interfacial shear stress on interdiffusion. Spectroscopic analysis of the interfaces using confocal Raman microscopy showed that the general relationships between interdiffusion, time (Fick's law) and temperature (Arrhenius relationship) are identical under both static and co‐extrusion conditions. However, the interdiffusion rate is significantly higher under shear influence. Since the prediction of the interdiffusion process supports material selection and process design in multilayer manufacturing, a simple analytical model was developed to quantify the effects of aforementioned material properties and processing conditions on the apparent mutual interdiffusion coefficient. Extrusion ; Materials science ; Polymer ; Composite material ; Die swell ; Shear rate ; Viscosity Polymer Foaming and Composites ; Polymer crystallization and properties ; Rheology and Fluid Dynamics Studies
Authors: S. Kumar | Mayanak K. Gupta | R. Mittal | Santhoshkumar Sundaramoorthy | Amitava Choudhury | Naresh C. Osti | А. И. Колесников | M. B. Stone | Yongqiang Cheng | S. L. Chaplot
Source: Journal of Materials Chemistry A (article, 2023-01-01)
Field: Materials Science — Materials Chemistry

Topology driven and soft phonon mode enabled Na-ion diffusion in quaternary chalcogenides, Na<sub>3</sub>ZnGaX<sub>4</sub> (X = S, and Se) A shallow potential energy surface facilitated by a specific structural topology of 32 g sites key to three dimensional Na-diffusion. Ion ; Phonon ; Diffusion ; Quaternary ; Mode (computer interface) ; Soft modes ; Materials science ; Topology (electrical circuits) ; Condensed matter physics ; Physics ; Optoelectronics ; Computer science ; Thermodynamics ; Mathematics ; Geology ; Quantum mechanics ; Combinatorics ; Paleontology Solid-state spectroscopy and crystallography ; Advancements in Battery Materials ; Advanced Thermoelectric Materials and Devices
Authors: J.W. Neri | A Cammarata | Alessandro Donazzi
Source: Journal of The Electrochemical Society (article, 2023-11-30)
Field: Materials Science — Materials Chemistry

Experimental and Model Investigation of a Solid Oxide Fuel Cell Operated Under Low Fuel Flow Rate A state-of-the-art anode-supported Ni-YSZ/YSZ/GSC/LSC SOFC with 16 cm 2 cathode area was tested at low anodic flow rate (6.25 Ncc min −1 cm −2 ) and large excess of air (93.75 Ncm 3 min −1 cm −2 ). These conditions are typical of stacks, where high H 2 utilization is targeted, but are uncommon in single cell testing. H 2 -based mixtures were supplied between 550 °C and 750 °C, varying the partial pressure of H 2 (between 93% and 21% with 7% H 2 O mol/mol) and H 2 O (between 10% and 50% H 2 O with 50% H 2 ). I/V and EIS measurements were collected and analyzed with a 1D+1D model of a SOFC with rectangular duct interconnectors. At 750 °C and 93% H 2 , 58% fuel utilization was obtained, which raised to 81% at 21% H 2 , driving the SOFC under internal diffusion control. The model analysis confirmed that nearly-isothermal conditions were retained thanks to efficient heat dissipation, and that air acted as a coolant. During testing, the contact resistance grew to 0.16 Ω cm 2 at 750 °C, limiting the SOFC’s performance to a maximum power density of 340 W cm −2 with 7% humidified H 2 . The kinetic parameters of the anodic reaction were derived by fitting, finding a positive order for H 2 (+0.9), and a negative order for H 2 O (−0.58). Anode ; Solid oxide fuel cell ; Isothermal process ; Cathode ; Analytical Chemistry (journal) ; Materials science ; Coolant ; Volumetric flow rate ; Fuel cells ; Oxide ; Power density ; Chemistry ; Electrode ; Thermodynamics ; Chemical engineering ; Metallurgy ; Physical chemistry ; Chromatography Advancements in Solid Oxide Fuel Cells ; Electronic and Structural Properties of Oxides ; Electrocatalysts for Energy Conversion
Authors: S. M. Rakibul Hasan Shawon | Sajib Kapali | Imi Bintey Fariha Rahman | Sharnali Islam | Khaleda Ali
Source: IEEE Access (article, 2023-01-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Switchable THz Guided Mode Enhancement in Subwavelength Thick PTFE — Polyimide Based Metamaterial Devices We report an efficient approach to enhance terahertz (THz)-guided modes for realizing subwavelength thick metamaterial devices (MMD). Here, a combination of hollow and slitted rings of the vanadium dioxide ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$VO_{2}$ </tex-math></inline-formula> )-based metasurface, having perfect impedance matching with free space, is considered to cause tight coupling in the unit cells while reducing transverse field components of the boundary. The consolidated dielectric layer of polytetrafluoroethylene (PTFE)-polyimide underneath, maintaining a gradual change in refractive indices, brings about further improvement for a broader spectrum. Through strategic and systematic design steps, a maximum impedance bandwidth of 5.68 THz, ranging from 4.42 to 10.10 THz, has been achieved here from a structure thinner than a wavelength. Additionally, mode-independent polarization insensitivity and tunability are attained through the symmetrical unit cell pattern of temperature-dependent <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$VO_{2}$ </tex-math></inline-formula> . Optimized design parameters agree with interference cancellation theory too. Validation of our presented design is performed using theoretical analysis based on equivalent circuit theory. The proposed design offers a new avenue for designing ultra-thin broadband absorbers, light modulators, etc. Terahertz radiation ; Metamaterial ; Materials science ; Polyimide ; Optoelectronics ; Optics ; Impedance matching ; Electrical impedance ; Physics ; Layer (electronics) ; Nanotechnology Metamaterials and Metasurfaces Applications ; Advanced Antenna and Metasurface Technologies ; Antenna Design and Analysis
Authors: Rajesh B. Gujar | Seraj A. Ansari | Prasanta K. Mohapatra | Richard J. M. Egberink | Jurriaan Huskens | Willem Verboom
Source: Industrial & Engineering Chemistry Research (article, 2023-03-31)
Field: Chemistry — Inorganic Chemistry

Highly Efficient Extraction Chromatography Resin Containing Hexa-<i>n</i>-Octyl Nitrilotriacetamide (HONTA) for Selective Recovery of Plutonium from Acidic Feeds An extraction chromatography resin was prepared by impregnating hexa-n-octyl nitrilotriacetamide (HONTA) on chromosorb-W. This resin shows very efficient performance for selective separation of Pu4+ over other actinides like uranium and americium. The distribution coefficient for Pu4+ (at 3 M HNO3) was on the order of 104 mL/g, with separation factors of >103 for other actinides. The extraction kinetics for Pu4+ was slow and took 20 min of shaking for reaching the equilibrium conditions and followed both the film diffusion and the intraparticle diffusion kinetic models. The Pu4+ sorption on the resin followed the Langmuir monolayer model with a sorption energy of 11.2 kJ/mol. The maximum Pu4+ loading capacity on the resin was 58.2 mg/g resin, which corresponds to 1:1 Pu/ligand complex formation. Excellent column performance was observed for selective separation of Pu4+ from a mixture of Pu, Am, and U in a 3 M HNO3 solution. Chemistry ; Sorption ; Actinide ; Americium ; Extraction (chemistry) ; Plutonium ; Nuclear chemistry ; Chromatography ; Chelating resin ; Adsorption ; Organic chemistry Radioactive element chemistry and processing ; Chemical Synthesis and Characterization ; Extraction and Separation Processes
Authors: P. Wetzel | Anna Katharina Sambale | Kai Uhlig | Markus Stommel | Benjamin Schneider | Jan-Martin Kaiser
Source: Polymers (article, 2023-08-12)
Field: Materials Science — Polymers and Plastics

Hygromechanical Behavior of Polyamide 6.6: Experiments and Modeling This paper investigates water absorption in polyamide 6.6 and the resulting hygroscopic swelling and changes in mechanical properties. First, sorption and swelling experiments on specimens from injection molded plates are presented. The observed swelling behavior is dependent on the melt flow direction of the injection molding process. Additionally, thermal analysis and mechanical tensile tests were performed for different conditioning states. The water sorption is accompanied by a decrease in the glass transition temperature and a significant reduction in stiffness and strength. Next, a sequentially coupled modeling approach is presented. A nonlinear diffusion model is followed by mechanical simulations accounting for swelling and concentration-dependent properties. For the mechanical properties, the notion of a "gap" temperature caused by the shift of the glass transition range due to water-induced plasticization is employed. This model enables the computation of local moisture concentration fields and the resultant swelling and changes in stress-strain behavior. Swelling ; Materials science ; Composite material ; Sorption ; Glass transition ; Absorption of water ; Polyamide ; Ultimate tensile strength ; Thermal diffusivity ; Diffusion ; Stiffness ; Molding (decorative) ; Plasticizer ; Thermodynamics ; Polymer ; Chemistry ; Adsorption Polymer crystallization and properties ; Epoxy Resin Curing Processes ; Injection Molding Process and Properties
Authors: A. E. Kostanyan | В. В. Белова | Yulia V. Tsareva | Maria M. Petyaeva
Source: Processes (article, 2023-06-09)
Field: Chemistry — Analytical Chemistry

Separation of Rare Earth Elements in Multistage Extraction Columns in Chromatography Mode: Experimental Study and Mathematical Simulation The application of liquid–liquid chromatography principles to solvent extraction processes in hydrometallurgy can greatly simplify rare earth metal separation technologies by separating multicomponent mixtures in one technological operation. In this study, the chromatographic separation of rare earth elements (REEs) in multistage extraction columns was experimentally studied under conditions of impulse sample injection—single and multiple loading of large volumes of metal salt solution into the installation. The results obtained showed the feasibility of operating sieve plate extraction columns in the liquid–liquid chromatography mode. A closed-loop recycling technology is proposed for the separation of rare earth elements in multistage extraction columns operating in the liquid–liquid chromatography mode. For further development and industrial implementation of this technology, experimental studies should be conducted on intensified multistage extraction columns, such as sectioned columns with agitators and vibrating plate columns. Computer simulation of the chromatographic separation of rare earth elements by closed-loop recycling liquid–liquid chromatography was carried out. Chromatography ; Extraction (chemistry) ; Sieve (category theory) ; Simulated moving bed ; Chemistry ; Rare earth ; Separation (statistics) ; Materials science ; Computer science ; Mineralogy ; Mathematics ; Adsorption Chromatography in Natural Products ; Crystallization and Solubility Studies ; Analytical Chemistry and Chromatography