jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Mithun Chowdhury | Xavier Monnier | Daniele Cangialosi | Rodney D. Priestley
Source: ACS Polymers Au (article, 2022-06-30)
Field: Materials Science — Materials Chemistry

Decoupling of Glassy Dynamics from Viscosity in Thin Supported Poly(<i>n</i>-butyl methacrylate) Films We utilized fast scanning calorimetry to characterize the glass transition temperature (<i>T</i> <sub>g</sub>) and intrinsic molecular mobility of low-molecular-weight poly(<i>n</i>-butyl methacrylate) thin films of varying thicknesses. We found that the <i>T</i> <sub>g</sub> and intrinsic molecular mobility were coupled, showing no film thickness-dependent variation. We further employed a unique noncontact capillary nanoshearing technique to directly probe layer-resolved gradients in the rheological response of these films. We found that layer-resolved shear mobility was enhanced with a reduction in film thickness, whereas the effective viscosity decreased. Our results highlight the importance of polymer-substrate attractive interactions and free surface-promoted enhanced mobility, establishing a competitive nanoconfinement effect in poly(<i>n</i>-butyl methacrylate) thin films. Moreover, the findings indicate a decoupling in the thickness-dependent variation of <i>T</i> <sub>g</sub> and intrinsic molecular mobility with the mechanical responses (shear mobility and effective viscosity). Materials science ; Glass transition ; Rheology ; Thin film ; Polymer ; Methacrylate ; Viscosity ; Decoupling (probability) ; Polymer chemistry ; Molecular dynamics ; Composite material ; Chemical engineering ; Nanotechnology ; Copolymer ; Chemistry ; Computational chemistry Material Dynamics and Properties ; Liquid Crystal Research Advancements ; Polymer crystallization and properties
Authors: Lucas Villatte | Maria-Isabel Rua-Taborda | Arnaud Ndayishimiye | Clive A. Randall | Alain Largeteau | Graziella Goglio | Catherine Elissalde | S. Bordère
Source: Materialia (article, 2022-04-12)
Field: Materials Science — Ceramics and Composites

Mechanisms and energetics in the early stages of solvent-assisted low-temperature sintering of ZnO Sintering ; Materials science ; Dilatometer ; Isothermal process ; Activation energy ; Energetics ; Solvent ; Hydrothermal circulation ; Kinetic energy ; Composite material ; Chemical engineering ; Thermodynamics ; Physical chemistry ; Chemistry Advanced ceramic materials synthesis ; Advanced materials and composites ; Thermal and Kinetic Analysis
Authors: Berkay KARAÇOR | Mustafa Özcanlı
Source: GAZI UNIVERSITY JOURNAL OF SCIENCE (article, 2022-03-22)
Field: Materials Science — Polymers and Plastics

Examination of Fiber Reinforced Composite Materials In recent years, various new and practical products have emerged thanks to rapidly developing science and technology to meet human needs and expectations. A variety of these products are new materials known as composites. The use of composites is also increasing, from the aircraft industry to the automobile industry, to other areas such as sports equipment, infrastructures. The goal of this research is to present a hybrid composite material that can be retainable and does not harm the environment that can be used in the automobile industry. This goal has been tried to be achieved by using natural fiber (flax fabric) reinforced glass fibers in different weights (86 gr/m² and 100 gr/m²). The vacuum assisted resin transfer molding (VARTM) system was used to fabricate the composite samples. Composite products produced during the study were tested with regard to mechanical (tensile strength, bending strength), hardness, and morphological (scanning electron microscopy). The results indicate that the tensile strength value of hybrid composites is 2.5 times and 1.7 times higher than that of homogeneous composites and flexural test results also 78% and 23% enhancement compared to single fiber composites. According to the hardness test measurement of hybrid composites, it was found that the hardness value changed with an increase of 14% and 33% compared to the homogeneous composite. Scanning Electron microscopy (SEM) analysis images also coincide with mechanical analysis results. The hybrid composites produced in the study have become a favorable option in diverse areas of use in the automotive industry, considering human health and environmental factors. Composite material ; Materials science ; Ultimate tensile strength ; Flexural strength ; Composite number ; Scanning electron microscope ; Automotive industry ; Fiber ; Glass fiber ; Transfer molding ; Izod impact strength test ; Tensile testing ; Natural fiber ; Fibre-reinforced plastic ; Engineering ; Mold Natural Fiber Reinforced Composites ; Mechanical Engineering and Vibrations Research ; Tribology and Wear Analysis
Authors: Xuexia Lin | Mengxing Su | Feixiang Fang | Jiafu Hong | Yumeng Zhang | Shu‐Feng Zhou
Source: Molecules (article, 2022-10-09)
Field: Materials Science — Materials Chemistry

Hierarchically Annular Mesoporous Carbon Derived from Phenolic Resin for Efficient Removal of Antibiotics in Wastewater Antibiotics have become a new type of environmental pollutant due to their extensive use. High-performance adsorbents are of paramount significance for a cost-effective and environmentally friendly strategy to remove antibiotics from water environments. Herein, we report a novel annular mesoporous carbon (MCN), prepared by phenolic resin and triblock copolymer F127, as a high-performance adsorbent to remove penicillin, streptomycin, and tetracycline hydrochloride from wastewater. The MCNs have high purity, rich annular mesoporosity, a high surface area (605.53 m<sup>2</sup>/g), and large pore volume (0.58 cm<sup>3</sup>/g), improving the adsorption capacity and facilitating the efficient removal of penicillin, streptomycin, and tetracycline hydrochloride from water. In the application of MCNs to treat these three kinds of residual antibiotics, the adsorption amounts of tetracycline hydrochloride were higher than penicillin and streptomycin, and the adsorption capacity was up to 880.6 mg/g. Moreover, high removal efficiency (99.6%) and excellent recyclability were achieved. The results demonstrate that MCN adsorbents have significant potential in the treatment of water contaminated with antibiotics. Tetracycline Hydrochloride ; Adsorption ; Penicillin ; Tetracycline ; Streptomycin ; Wastewater ; Mesoporous material ; Antibiotics ; Tetracycline antibiotics ; Chemistry ; Nuclear chemistry ; Chemical engineering ; Organic chemistry ; Environmental engineering ; Environmental science ; Catalysis ; Biochemistry Covalent Organic Framework Applications ; Adsorption and biosorption for pollutant removal ; Nanomaterials for catalytic reactions
Authors: Luís Victor Muller Fabris | Jean Carlos Cardozo da Silva
Source: Journal of Microwaves Optoelectronics and Electromagnetic Applications (article, 2022-11-28)
Field: Materials Science — Materials Chemistry

Simulation of Current Pulses and Sound Waves Resulting from Partial Discharges in a Needle-Plane Geometry in Air Partial discharges can occur in different types of electric equipment and cause progressive insulation deterioration, so there is interest in monitoring partial discharges for assessing the state of the isolation of an electric system and to predict failures. Techniques to detect partial discharges, such as detecting ultrasonic emission, have been proposed in the literature, but as various effects can co-occur during a discharge, identifying characteristics in sound and pressure waveforms and correlating then with discharge characteristics is difficult. Simulations can assist in these correlations by allowing the isolation of the different phenomena. In this work the drift diffusion model, including photoionization, is coupled with the linearized compressible Navier-Stokes equations to simulate ultrasonic waves produced by partial discharges. Previous works have used the incompressible Navier-Stokes equations, so they can simulate ionic wind produced by the Trichel pulses, but no sound. In the literature, simulations have focused either on streamers or Trichel pulses. In this work both discharges and produced sound waves are successfully simulated for the needle-plane geometry in air. The electric current and charge per pulse are compared with experimental results reported in the literature for the same discharge conditions. The simulations have demonstrated that the sound waves depart from the electrode tip for the Trichel pulses, and for the streamers two sound waves are produced, one from the electrode tip and the other from the whole discharge length. Differences in the wave front with respect to the relative position to the electrode tip were analyzed, showing that near the discharge spot the sound wave is not a spherical wavefront. The sound wave for one of the discharges in the Trichel pulse regime was compared with experimental results in the literature. Results are in good agreement with the experimental data found in the literature. Both current and sound waves were successfully predicted and correlated with the discharge, results that can be used to help in the detection of partial discharges. Acoustics ; Partial discharge ; Mechanics ; Ultrasonic sensor ; Compressibility ; Sound pressure ; Waveform ; Electric discharge ; Current (fluid) ; Materials science ; Electrode ; Physics ; Voltage High voltage insulation and dielectric phenomena ; Aerosol Filtration and Electrostatic Precipitation ; Power Transformer Diagnostics and Insulation
Authors: Michael Rhode | Jonathan Nietzke | Tobias Mente | Tim Richter | Thomas Kannengießer
Source: Journal of Materials Engineering and Performance (article, 2022-02-28)
Field: Materials Science — Metals and Alloys

Characterization of Hydrogen Diffusion in Offshore Steel S420G2+M Multi-layer Submerged Arc Welded Joint Abstract As onshore installation capacity is limited, the increase in the number of offshore wind turbines (OWT) is a major goal. In that connection, the OWTs continuously increase in size and weight and demand adequate foundations concepts like monopiles or tripods. These components are typically manufactured from welded mild steel plates with thickness up to 200 mm. The predominant welding technique is submerged arc welding (SAW). In accordance with the standards, the occurrence of hydrogen-assisted cracking is anticipated by either a minimum waiting time (MWT, before non-destructive testing of the welded joint is allowed) at ambient or a hydrogen removal heat treatment (HRHT) at elevated temperatures. The effectiveness of both can be estimated by calculation of the diffusion time, i.e., diffusion coefficients. In this study, these coefficients are obtained for the first time for a thick-walled S420G2+M offshore steel grade and its multi-layer SAW joint. The electrochemical permeation technique at ambient temperature is used for the determination of diffusion coefficients for both the base material and the weld metal. The coefficients are within a range of 10 −5 to 10 −4 mm 2 /s (whereas the weld metal had the lowest) and are used for an analytical and numerical calculation of the hydrogen diffusion and the related MWT. The results showed that long MWT can occur, which would be necessary to significantly decrease the hydrogen concentration. Weld metal diffusion coefficients at elevated temperatures were calculated from hydrogen desorption experiments by carrier gas hot extraction. They are within a range of 10 −3 mm 2 /s and used for the characterization of a HRHT dwell-time. The analytical calculation shows the same tendency of long necessary times also at elevated temperatures. That means the necessary time is strongly influenced by the considered plate thickness and the estimation of any MWT/HRHT via diffusion coefficients should be critically discussed. Materials science ; Welding ; Diffusion ; Hydrogen ; Base metal ; Joint (building) ; Metallurgy ; Submerged arc welding ; Offshore wind power ; Composite material ; Cracking ; Arc welding ; Structural engineering ; Turbine ; Mechanical engineering ; Thermodynamics Hydrogen embrittlement and corrosion behaviors in metals ; Corrosion Behavior and Inhibition ; Fatigue and fracture mechanics
Authors: Xiang Zheng | Taylor Moule | James W. Pomeroy | Masataka Higashiwaki | Martin Kuball
Source: Applied Physics Letters (article, 2022-02-14)
Field: Materials Science — Electronic, Optical and Magnetic Materials

A trapping tolerant drain current based temperature measurement of <i>β</i>-Ga2O3 MOSFETs The drain current temperature dependence is an efficient way to determine the channel temperature in semiconductor devices; however, it has been challenging to use due to the potential interference of trapping effects. A trapping tolerant method is proposed, illustrated here for Ga2O3 MOSFETs, making in situ temperature measurements possible, allowing a thermal resistance of 59 K·mm/W to be measured in Ga2O3 MOSFETs. However, neglecting the effect of trapping causes an error of ∼15% in the channel temperature measured using the drain current. 3D simulations show that the measured channel temperature is the average temperature value between source and drain contact. Trapping ; MOSFET ; Materials science ; Temperature measurement ; Current (fluid) ; Optoelectronics ; Drain-induced barrier lowering ; Channel (broadcasting) ; Semiconductor device ; Channel length modulation ; Condensed matter physics ; Analytical Chemistry (journal) ; Chemistry ; Field-effect transistor ; Electrical engineering ; Transistor ; Nanotechnology ; Voltage ; Physics ; Thermodynamics Ga2O3 and related materials ; ZnO doping and properties ; Electronic and Structural Properties of Oxides
Authors: Massimo Petriccone | Régis Laurent | Cédric‐Olivier Turrin | Rosa Marı́a Sebastián | Anne‐Marie Caminade
Source: Organics (article, 2022-08-03)
Field: Materials Science — Polymers and Plastics

Specific Bifunctionalization on the Surface of Phosphorus Dendrimers Syntheses and Properties Dendrimers are highly branched macromolecules possessing, in most cases, identical terminal functions. However, it is sometimes desirable to have two types of surface functions in order to fulfil specific properties. The stochastic functionalization is frequently used for such purposes, but the presence of an uncontrolled number of each type of terminal function, albeit acceptable for research purposes, has no practical use. Thus, it is highly desirable to find strategies suitable for the precise grafting of two different functional groups on the surface of dendrimers. The easiest way, and the most widely used, consists in using a bifunctional monomer to be grafted to all of the surface functions of the dendrimers. Two other strategies are known but are rarely used: the modification of an existing function, to generate two functions, and the sequential grafting of one function then of a second function. The three methods are illustrated in this review with polyphosphorhydrazone (PPH) dendrimers, together with their properties as catalysts, for materials, and as biological tools. Dendrimer ; Bifunctional ; Surface modification ; Grafting ; Macromolecule ; Function (biology) ; Monomer ; Materials science ; Combinatorial chemistry ; Computer science ; Nanotechnology ; Polymer ; Chemistry ; Polymer chemistry ; Organic chemistry ; Catalysis ; Physical chemistry ; Biology Dendrimers and Hyperbranched Polymers ; Molecular Junctions and Nanostructures ; Ferrocene Chemistry and Applications
Authors: Fagui Lu | Kuan Lu | Gui Zhao | Song Zhou | Bowen He | Yixiao Zhang | Jian Xu | Yongwang Li | Xi Liu | Liwei Chen
Source: RSC Advances (article, 2022-01-01)
Field: Chemistry — Organic Chemistry

A PtPdCoCuNi high-entropy alloy nanocatalyst for the hydrogenation of nitrobenzene High-entropy alloys (HEAs) with multiple elements in near-equiatomic proportions hold great promise in heterogeneous catalysis because of their exceptional physicochemical properties governed by synergy. Herein, we prepared PtPdCoCuNi HEA nanoparticles <i>via</i> a one-step colloid-based route and tested their catalytic performance for nitrobenzene hydrogenation to aniline. The SiO<sub>2</sub> supported PtPdCoCuNi displays 93.9% yield of aniline at 80 °C, which is 2.11 times that of PtPd/SiO<sub>2</sub>. Even at room temperature, a 47.4% yield of aniline is attained with the PtPdCoCuNi/SiO<sub>2</sub> catalyst. DRIFTS experiments indicate formation of isolated Pt and Pd sites after alloying the transition metals and evidence a stronger interaction between the HEA catalyst and nitrobenzene. Both XPS data and DFT calculations disclose charge transfer to Pt and Pd species, which eventually enhance the interaction between nitrobenzene and the isolated metal sites and the hydrogenation activity as well. The experimental and theoretical results shed light on mechanistic understanding of the unique catalytic performance of the HEA nanocatalyst and pave a new avenue to realize the high catalytic performance of nitrobenzene hydrogenation over well-isolated noble metal sites with specific geometries. Nitrobenzene ; Alloy ; Materials science ; Chemistry ; Chemical engineering ; Catalysis ; Metallurgy ; Organic chemistry ; Engineering Nanomaterials for catalytic reactions ; Catalytic Processes in Materials Science ; Catalysis and Hydrodesulfurization Studies
Authors: Yahya S. Alqahtani | Bandar A. Alyami | Ali O. Alqarni | Mater H. Mahnashi | Anser Ali | Qamar Javed | Mubashir Hassan | Muhammad Ehsan
Source: BioMed Research International (article, 2022-01-01)
Field: Chemistry — Organic Chemistry

Cephalosporin as Potent Urease and Tyrosinase Inhibitor: Exploration through Enzyme Inhibition, Kinetic Mechanism, and Molecular Docking Studies In present study, eleven cephalosporin drugs were selected to explore their new medically important enzyme targets with inherited safety advantage. To this end, selected drugs with active ingredient, cefpodoxime proxetil, ceftazidime, cefepime, ceftriaxone sodium, cefaclor, cefotaxime sodium, cefixime trihydrate, cephalexin, cefadroxil, cephradine, and cefuroxime, were evaluated and found to have significant activity against urease (IC50 = 0.06 ± 0.004 to 0.37 ± 0.046 mM) and tyrosinase (IC50 = 0.01 ± 0.0005 to 0.12 ± 0.017 mM) enzymes. Urease activity was lower than standard thiourea; however, tyrosinase activity of all drugs outperforms (ranging 6 to 18 times) the positive control: hydroquinone (IC50 = 0.18 ± 0.02 mM). Moreover, the kinetic analysis of the most active drugs, ceftriaxone sodium and cefotaxime sodium, revealed that they bind irreversibly with both the enzymes; however, their mode of action was competitive for urease and mixed-type, preferentially competitive for tyrosinase enzyme. Like <i>in vitro</i> activity, ceftriaxone sodium and cefotaxime sodium docking analysis showed their considerable binding affinity and significant interactions with both urease and tyrosinase enzymes sufficient for downstream signaling responsible for observed enzyme inhibition <i>in vitro</i>, purposing them as potent candidates to control enzyme-rooted obstructions in future. Enzyme inhibition ; Urease ; Chemistry ; Enzyme ; Docking (animal) ; Tyrosinase ; Cephalosporin ; Biochemistry ; Pharmacology ; Biology ; Medicine ; Antibiotics Synthesis and biological activity ; Synthesis and Characterization of Heterocyclic Compounds ; Click Chemistry and Applications
Authors: Gerso Pereira Alexandre | Jorge Luiz Souza Simão | Maria Olivia Amaral Tavares | IZABELLA MARIANA S. ZUFFO | STÉPHANIE V. PRADO | Joseilson Alves de Paiva | Mustapha Abubakar | Anselmo E. de Oliveira | Lucília Kato | Vanessa Gisele Pasqualotto Severino
Source: Anais da Academia Brasileira de Ciências (article, 2022-01-01)
Field: Chemistry — Organic Chemistry

Dereplication by HPLC-ESI-MS and antioxidant activity of phenolic compounds from Banisteriopsis laevifolia (Malpighiaceae) The genus Banisteriopsis (Malpighiaceae) comprises 77 genera and 1,300 species. Despite efforts to provide detailed information about the chemical wealth of B. laevifolia, this article provides the identification and characterization of compounds from the ethanolic extracts of the leaves and flowers using advanced methodologies which include high-performance liquid chromatography coupled to tandem mass spectrometry, which contribute to the knowledge about compounds present in the genus Banisteriopsis. The dereplication aided by Global Natural Products Social Molecular Networking afforded the identification of seven compounds reported for this species for the first time. A mixture of two known flavonoids and a diterpenoid, 18-hydroxy-ent-halima-1(10),13-(E)-dien-15-oic acid, were isolated by conventional separation methods. The elevated 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity observed in some samples was attributed to either the type of extract, the presence of 3,4,5-trihydroxybenzoic acid, or the influence of the substitution pattern and the synergistic effect of the compounds present. Principal Component Analysis was applied to correlate mass spectrometry data with the antioxidant activity of the samples. The high diversity of metabolites found in this study and those which have been reported for Banisteriopsis strongly recommends further investigation into the chemical and biological properties of these species. Malpighiaceae ; Chemistry ; Antioxidant ; Mass spectrometry ; High-performance liquid chromatography ; Tandem mass spectrometry ; Chemical constituents ; Genus ; Chromatography ; Terpenoid ; Organic chemistry ; Botany ; Biology ; Stereochemistry Chemical synthesis and alkaloids ; Biological and pharmacological studies of plants ; Phytochemistry and Biological Activities
Authors: Xiaoya Zhao | Yan Huang | Siai Zhou | Jiaming Ao | Hui Cai | Katsunori Tanaka | Yukishige Ito | Akihiro Ishiwata | Feiqing Ding
Source: Frontiers in Chemistry (review, 2022-05-26)
Field: Chemistry — Organic Chemistry

Recent Chemical and Chemoenzymatic Strategies to Complex-Type N-Glycans Glycosylation is one of the major forms of protein post-translational modification. <i>N</i>-glycans attached to proteins by covalent bonds play an indispensable role in intercellular interaction and immune function. In human bodies, most of the cell surface glycoproteins and secreted glycopeptides are modified with complex-type <i>N</i>-glycans. Thus, for analytical or medicinal purposes, efficient and universal methods to provide homogeneous complex-type <i>N</i>-glycans have been an urgent need. Despite the extremely complicated structures, tremendous progress in the synthesis of <i>N</i>-glycans has been achieved. On one hand, chemical strategies are shown to be effective to prepare core oligosaccharides of <i>N</i>-glycans by focusing on stereoselective glycosylations such as β-mannosylation and α-sialylation, as well as the methodology of the <i>N</i>-glycan assembly. On the other hand, chemoenzymatic strategies have also become increasingly powerful in recent years. This review attempts to highlight the very recent advancements in chemical and chemoenzymatic strategies for eukaryotic complex-type <i>N</i>-glycans. Glycan ; Glycosylation ; Glycoprotein ; Chemistry ; Function (biology) ; Biochemistry ; Computational biology ; Biology ; Cell biology Carbohydrate Chemistry and Synthesis ; Glycosylation and Glycoproteins Research ; Peptidase Inhibition and Analysis