jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Adrien J. Terricabras | Joshua Ferrigno | Ling Wang | Marat Khafizov | Andrew Nelson | S.J. Zinkle
Source: Journal of Applied Physics (article, 2022-08-17)
Field: Materials Science — Ceramics and Composites

Thermal conductivity evaluation of ion irradiated Si3N4 and ZrN ceramics using spatial domain thermoreflectance Nitride ceramics have been investigated for different applications in the nuclear industry, such as space nuclear power, fusion reactor diagnostics and plasma heating, inert matrix fuels, and accident tolerant fuels. Although thermal conductivity remains one of the most important properties to track following irradiation, traditional techniques such as laser flash and xenon flash are limited to bulk sample characterization, which requires lengthy and cost-consuming neutron irradiation. This work used spatial domain thermoreflectance (SDTR) for the micrometer-scale measurement of thermal conductivity in 15 MeV Ni ion-irradiated silicon nitride and zirconium nitride from 1 to 50 dpa and 300 to 700 °C. The SDTR-measured unirradiated thermal conductivity was found to be consistent with the published data on bulk samples. Electrically conductive ZrN exhibits modest reduction after irradiation which is minimal at the highest irradiation temperatures. In electrically insulating Si3N4, the reduction is more significant and unlike ZrN, the reduction remains significant even at a higher irradiation temperature. The thermal resistance evolution following irradiation was compared with lattice swelling, which was determined using grazing incidence x-ray diffraction, and radiation-induced defects were observed using transmission electron microscopy. A saturation value was observed between 15 and 50 dpa for thermal conductivity degradation in both nitride ceramics and a direct correlation with high-temperature defect recombination was observed, as well as the potential presence of additional carrier scattering mechanisms. Materials science ; Irradiation ; Thermal conductivity ; Nitride ; Laser flash analysis ; Analytical Chemistry (journal) ; Silicon nitride ; Ceramic ; Composite material ; Optoelectronics ; Silicon ; Chemistry Advanced ceramic materials synthesis ; Semiconductor materials and devices ; Nuclear Materials and Properties
Authors: E.A. Hodille | Jesper Byggmästar | Y. Ferro | K. Nordlund
Source: Journal of Physics Condensed Matter (article, 2022-07-21)
Field: Materials Science — Materials Chemistry

Molecular dynamics study of hydrogen isotopes at the Be/BeO interface Molecular dynamics simulations are used to investigate the behaviour of D atoms at two interfaces between beryllium (Be) and beryllium oxide (BeO). After relaxation of the simulation cell, there are (a) localised defects at the interface and (b) a hexagonal misfit dislocation network creating a succession of compressed and expanded area from each side of the interface. The simulations between 750 K and 1500 K for tens to hundreds of nanoseconds show that both interfaces act as trapping sites for D atoms. The simulations also show that D atoms tend to migrate in the material where the hydrogen isotope solubility is the highest as predicted by thermodynamics. However, the simulations also shows that there are additional kinetic barriers (D trapping sites, D<sub>2</sub>formation/dissociation in BeO) that slow down the path to equilibrium. These additional kinetic barriers may influence the fuel retention and permeation in Be materials. Molecular dynamics ; Beryllium ; Dissociation (chemistry) ; Hydrogen ; Trapping ; Materials science ; Chemical physics ; Kinetic energy ; Oxide ; Hexagonal crystal system ; Permeation ; Relaxation (psychology) ; Crystallography ; Physical chemistry ; Chemistry ; Computational chemistry ; Physics Fusion materials and technologies ; Nuclear Materials and Properties ; Hydrogen Storage and Materials
Authors: Theresa Hennig | Michael Kühn
Source: Advances in geosciences (article, 2022-10-20)
Field: Chemistry — Inorganic Chemistry

Reactive transport simulations of uranium migration in the Opalinus Clay depend on ion speciation governed by underlying thermodynamic data Abstract. Safety assessments must demonstrate that radionuclides in potential disposal sites are retained within the containment providing rock zone. The impact of thermodynamic data on calculated migration lengths resulting from reactive transport simulations is quantified for the example of uranium in the hydrogeological system of the Opalinus Clay at Mont Terri. In this geochemical system, speciation is controlled by the calcite-carbonate-ion system. Aqueous uranium is mainly present as U(VI) as ternary complexes with calcium or magnesium together with carbonate. Previous simulations using the first NEA update of thermodynamic data for uranium indicated that the anionic complex CaUO2(CO3)32- is the predominant species with a maximum migration distance of 50 m after one million years. The NEA published an update of the thermodynamic data for uranium, what, in turn, changes the predominant species from anionic to almost only the neutral ternary complex Ca2UO2(CO3)3. With identical simulations, except for the application of the second NEA update, a maximum distance of 80 m was obtained. This can be attributed to a decrease in sorption capacity due to a stronger complexation of uranium with calcium and carbonate. Therefore, the impact of the change in the underlying thermodynamic data can be quantified with +30 m. Our work clearly shows how sensitive migration lengths resulting from reactive transport simulations are to the model conceptualisation and selection of underlying data. Consequently, the compilation and further development of data sets and a site specific investigation are indispensable for reliable outcomes of transport simulations, and thus of performance assessments. Uranium ; Carbonate ; Calcite ; Actinide ; Sorption ; Ternary operation ; Genetic algorithm ; Chemistry ; Hydrogeology ; Geochemical modeling ; Mineralogy ; Geology ; Inorganic chemistry ; Materials science ; Physical chemistry ; Dissolution ; Metallurgy Radioactive element chemistry and processing ; Groundwater flow and contamination studies ; Radioactivity and Radon Measurements
Authors: Zhongchao Fu | Nan Wu | Haibo Long | Jianming Wang | Jun Zhang | Zhaoxia Hou | Xiaodong Li | Xudong Sun
Source: Coatings (article, 2022-07-30)
Field: Materials Science — Ceramics and Composites

Fabrication of Highly Transparent Y2O3 Ceramics via Colloidal Processing Using ZrO2-Coated Y2O3 Nanoparticles An easy approach is described for the preparation of ZrO2-coated Y2O3 nanopowder from a solution of zirconium nitrate with commercial Y2O3 nanopowder. The evolution process of the ZrO2 coating layer upon calcination, such as the phase and microstructure of the particles’ surface, was studied. Calcination of the powder at 700 °C resulted in ZrO2-coated Y2O3 nanopowder. The rheological properties of the suspensions of ZrO2-coated Y2O3 powders were studied. A well-dispersed suspension with a solid loading of 35.0 vol% using ZrO2-coated Y2O3 nanopowder was obtained. The consolidated green body obtained by the centrifugal casting method showed improved homogeneity with a relative density of 50.2%. Transparent ceramic with high transparency and an average grain size of 1.7 µm was obtained by presintering at 1500 °C for 16 h in air, followed by post-HIP at 1550 °C for 2 h under 200 MPa pressure. The in-line transmittance at the wavelength of 1100 nm (1.0 mm thick) reached 81.4%, close to the theoretical transmittance of Y2O3 crystal. Materials science ; Ceramic ; Calcination ; Microstructure ; Nanoparticle ; Transparent ceramics ; Coating ; Transmittance ; Fabrication ; Composite material ; Cubic zirconia ; Grain size ; Green body ; Sintering ; Nanotechnology ; Optoelectronics Advanced ceramic materials synthesis ; High-Temperature Coating Behaviors ; Glass properties and applications
Authors: Donghao Wen | Quanfeng Li | Yiyi Ou | Yunlin Yang | Zeming Qi | P. Dorenbos | H. Liang
Source: Dalton Transactions (article, 2022-01-01)
Field: Materials Science — Materials Chemistry

VUV-UV-vis photoluminescence, X-ray radioluminescence and energy transfer dynamics of Ce<sup>3+</sup> and Eu<sup>2+</sup> in Sr<sub>2</sub>MgSi<sub>2</sub>O<sub>7</sub> Ce<sup>3+</sup> and Eu<sup>2+</sup> doped and Ce<sup>3+</sup>-Eu<sup>2+</sup> co-doped Sr<sub>2</sub>MgSi<sub>2</sub>O<sub>7</sub> phosphors are prepared <i>via</i> a high-temperature solid-state reaction technique. The synchrotron radiation vacuum ultraviolet-ultraviolet (VUV-UV) excitation and ultraviolet-visible (UV-vis) emission spectra of diluted Ce<sup>3+</sup> and Eu<sup>2+</sup> doped Sr<sub>2</sub>MgSi<sub>2</sub>O<sub>7</sub> samples are measured at cryogenic temperatures. The electron-vibrational interaction (EVI) between Ce<sup>3+</sup> and its surroundings is analyzed. The dependencies of the 4f-5d transitions of Ce<sup>3+</sup> on the structure of the host compounds Sr<sub>2</sub>MgSi<sub>2</sub>O<sub>7</sub>, Ba<sub>2</sub>MgSi<sub>2</sub>O<sub>7</sub> and BaMg<sub>2</sub>Si<sub>2</sub>O<sub>7</sub> are discussed in detail. Then the thermal quenching channel is proposed based on the measurements of temperature dependent luminescence intensities and decay times of Ce<sup>3+</sup> and Eu<sup>2+</sup> in Sr<sub>2</sub>MgSi<sub>2</sub>O<sub>7</sub>, and the Ce<sup>3+</sup> → Eu<sup>2+</sup> energy transfer mechanism is understood by three luminescence dynamic models. In addition, Sr<sub>2</sub>MgSi<sub>2</sub>O<sub>7</sub>:Ce<sup>3+</sup>/Eu<sup>2+</sup> samples are evaluated for the possibilities of X-ray detection applications using X-ray excited luminescence (XEL) spectroscopy, and it was found that they are not suitable. Radioluminescence ; Photoluminescence ; Energy transfer ; Materials science ; Radiochemistry ; Atomic physics ; Chemistry ; Analytical Chemistry (journal) ; Crystallography ; Physics ; Scintillator ; Optics ; Optoelectronics Luminescence Properties of Advanced Materials ; Glass properties and applications ; Nuclear materials and radiation effects
Authors: T.M. Weilert | Kyle L. Walton | S.K. Loyalka | John D. Brockman
Source: Journal of Nuclear Materials (article, 2022-01-17)
Field: Materials Science — Materials Chemistry

Europium diffusion in IG-110 nuclear graphite Europium ; Diffusion ; Graphite ; Analytical Chemistry (journal) ; Materials science ; Chemistry ; Inductively coupled plasma ; Strontium ; Nuclear chemistry ; Plasma ; Chromatography ; Thermodynamics ; Metallurgy ; Nuclear physics ; Ion ; Physics ; Organic chemistry Nuclear Materials and Properties ; Nuclear reactor physics and engineering ; Graphite, nuclear technology, radiation studies
Authors: Zarife Nigâr Özdemir Kumral | Oscar Zannou | İlkay Koca
Source: Discover Food (article, 2022-03-31)
Field: Chemistry — Analytical Chemistry

Assessment of the aluminium contents of black tea and black tea infusions Abstract The aluminium (Al) can cause health problems to human being at overdose. The black tea is among the most common beverages in the world but may contain higher amount of Al. This study was conducted to determine Al content in black tea produced in Rize, Tabzon and Giresun/ Turkey and amount of Al transferred into tea infusions. Tea infusions were prepared for 15, 30, 45 and 60 min and the Al content was determined using the inductively coupled plasma optical emission spectroscopy (ICP-OES). The Al content in black teas was ranged from 8177.75 ± 1167.76 to 15,657.72 ± 1060.05 mg/kg. Al content of samples taken from Trabzon were lower than the Al contents of samples collected from Rize and Giresun. Infusion time effected significantly the amount of Al transferred into the tea infusions (p &lt; 0.05). The Al content in black teas was significantly influenced by the production location and depended on the harvest season (p &gt; 0.05). Black tea ; Aluminium ; Chemistry ; Green tea ; Human health ; Food science ; Horticulture ; Biology ; Medicine Heavy Metals in Plants ; Therapeutic Uses of Natural Elements ; Heavy metals in environment
Authors: Yutai Cai | Ken Chen | Wenzhong Zhou | Long Gu
Source: Frontiers in Energy Research (article, 2022-09-27)
Field: Materials Science — Materials Chemistry

Multiphysics thermo-mechanical behavior modeling for annular uranium-plutonium mixed oxide fuels in a lead-cooled fast reactor Understanding and predicting nuclear fuel behavior is the cornerstone for fuel design and optimization, and the safe and economic operation of nuclear reactors. Due to the excellent neutronic economy and safe operational characteristics of lead/lead-bismuth-based liquid metal coolant, lead-cooled fast reactor (LFR) has received much attention and has been regarded as one of the top candidate reactors for Generation IV nuclear power plants. Mixed oxide (MOX) fuel is beneficial to improve fuel cycle utilization and consume weapons-grade plutonium, among which hollow MOX fuel has excellent heat transfer advantages, which can further improve fuel economy and safety, and has good development prospects. In this work, an annular uranium-plutonium mixed oxide (MOX) fuel operating in a liquid lead/lead-bismuth cooled fast reactor is modeled and simulated to predict its behavior under transient and steady-state operation. This model has several modules working in a fully coupled approach based on COMSOL Multiphysics, such as heat transfer, fuel burnup, oxygen redistribution, plutonium redistribution, porosity evolution, fission gas release, JOG growth, and grain size evolution. The modeling results were benchmarked with the existing codes and experimental data, and the results were in satisfactory agreement. The parameters analysis was carried out in this work. Consistent with the solid MOX fuel, the O/M ratio (or deviation from the stoichiometry of oxygen) significantly affects temperature evolution, fission gas migration and release behavior, and plutonium redistribution. Linear power also has a significant influence on fuel performance. MOX fuel ; Multiphysics ; Plutonium ; Nuclear engineering ; Fuel element failure ; Materials science ; Burnup ; Nuclear fuel ; Fission products ; Nuclear reactor core ; Coolant ; Plutonium-240 ; Spent nuclear fuel ; Chemistry ; Radiochemistry ; Nuclear physics ; Engineering ; Fission ; Plutonium-239 ; Neutron ; Mechanical engineering ; Thermodynamics ; Physics Nuclear Materials and Properties ; Nuclear reactor physics and engineering ; Nuclear Engineering Thermal-Hydraulics
Authors: Mike Tebyetekerwa | Thien N. Truong | Wei Yan | Cheng Tang | Ary Anggara Wibowo | James Bullock | Aijun Du | Cheng Yan | Daniel Macdonald | Hieu T. Nguyen
Source: Advanced Materials Interfaces (article, 2022-10-03)
Field: Materials Science — Materials Chemistry

Twist Angle Effects on the Absorbance, Carrier Lifetime, and Diffusion Properties in Low Dimension <i>Type‐II</i> MoS<sub>2</sub>/WS<sub>2</sub> Heterobilayers Abstract Atomically thin two‐dimensional (2D) transition metal dichalcogenides (TMDs) are promising materials for photovoltaic (PV) applications. Their self‐terminated nature and strong absorption characteristics introduce an unprecedented possibility for high voltages to bandgap ratios, with secondary benefits including the potential for high internal quantum efficiencies/low recombination and strong absorption coefficients coupled with stability in a range of environments. However, despite the promise of such material systems, their PV performances still lag behind the conventional 3D materials. In principle, one possible way to manipulate the behavior of a 2D heterobilayer structure is to change its interlayer twist angle. In this study, the effects of twist angle between vertically stacked type‐II MoS 2 /WS 2 heterobilayers on fundamental optical properties such as light absorbance, excess carrier lifetime, and diffusion are reported. These properties can have a direct effect on the final PV performance of these heterobilayers. It is found that the interlayer twist in MoS 2 /WS 2 heterobilayers does not affect their absorbance. However, the carrier lifetime and photon emission across the heterobilayers are modulated with the interlayer twist. These findings could be useful to facilitate the optimization of monolayer TMD‐based optoelectronic devices. Materials science ; Absorbance ; Absorption (acoustics) ; Monolayer ; Optoelectronics ; Diffusion ; Carrier lifetime ; Optics ; Nanotechnology ; Silicon ; Composite material 2D Materials and Applications ; Perovskite Materials and Applications ; Graphene research and applications
Authors: María Sánchez-Milla | Ester Hernández-Corroto | Javier Sánchez‐Nieves | Rafael Gómez | Marı́a Luisa Marina | María Concepción García | F. Javier de la Mata
Source: International Journal of Molecular Sciences (article, 2022-12-17)
Field: Materials Science — Polymers and Plastics

Immobilization of Alcalase on Silica Supports Modified with Carbosilane and PAMAM Dendrimers Enzyme immobilization is a powerful strategy for enzyme stabilization and recyclability. Materials covered with multipoint molecules are very attractive for this goal, since the number of active moieties to attach the enzyme increases with respect to monofunctional linkers. This work evaluates different dendrimers supported on silica to immobilize a protease enzyme, Alcalase. Five different dendrimers were employed: two carbosilane (CBS) dendrimers of different generations (SiO<sub>2</sub>-G<sub>0</sub>Si-NH<sub>2</sub> and SiO<sub>2</sub>-G<sub>1</sub>Si-NH<sub>2</sub>), a CBS dendrimer with a polyphenoxo core (SiO<sub>2</sub>-G<sub>1</sub>O<sub>3</sub>-NH<sub>2</sub>), and two commercial polyamidoamine (PAMAM) dendrimers of different generations (SiO<sub>2</sub>-G<sub>0</sub>PAMAM-NH<sub>2</sub> and SiO<sub>2</sub>-G<sub>1</sub>PAMAM-NH<sub>2</sub>). The results were compared with a silica support modified with a monofunctional molecule (2-aminoethanethiol). The effect of the dendrimer generation, the immobilization conditions (immobilization time, Alcalase/SiO<sub>2</sub> ratio, and presence of Ca<sup>2+</sup> ions), and the digestion conditions (temperature, time, amount of support, and stirring speed) on Alcalase activity has been evaluated. Enzyme immobilization and its activity were highly affected by the kind of dendrimer and its generation, observing the most favorable behavior with SiO<sub>2</sub>-G<sub>0</sub>PAMAM-NH<sub>2</sub>. The enzyme immobilized on this support was used in two consecutive digestions and, unlike CBS supports, it did not retain peptides released in the digestion. Dendrimer ; Chemistry ; Immobilized enzyme ; Enzyme ; Protease ; Combinatorial chemistry ; Molecule ; Organic chemistry Dendrimers and Hyperbranched Polymers ; Enzyme Catalysis and Immobilization ; Polymer Surface Interaction Studies
Authors: D. Francis | Sannia Farooque | Archie Meager | Didi Derks | Abbie Leggott | Stuart L. Warriner | Alex J. O’Neill | Adam Nelson
Source: Organic & Biomolecular Chemistry (article, 2022-01-01)
Field: Chemistry — Organic Chemistry

Algorithm-driven activity-directed expansion of a series of antibacterial quinazolinones Activity-directed synthesis (ADS) is a structure-blind, function driven approach that can drive the discovery of bioactive small molecules. In ADS, arrays of reactions are designed and executed, and the crude product mixtures are then directly screened to identify reactions that yield bioactive products. The design of subsequent reaction arrays is then informed by the hit reactions that are discovered. In this study, algorithms for reaction array design were developed in which the reactions to be executed were selected from a large set of virtual reactions; the reactions were selected on the basis of similarity to reactions known to yield bioactive products. The algorithms were harnessed to design arrays of photoredox-catalysed alkylation reactions whose crude products were then screened for inhibition of growth of <i>S. aureus</i> ATCC29213. It was demonstrated that the approach enabled expansion of a series of antibacterial quinazolinones. It is envisaged that such algorithms could ultimately enable fully autonomous activity-directed molecular discovery. Chemistry ; Series (stratigraphy) ; Antibacterial activity ; Combinatorial chemistry ; Bacteria ; Paleontology Quinazolinone synthesis and applications ; Innovative Microfluidic and Catalytic Techniques Innovation ; Catalytic C–H Functionalization Methods
Authors: Nasrin Nassiri Koopaei | Mehrasa Shademani | Nasrin Shirzad Yazdi | Raheleh Tahmasvand | Mina Dehbid | Mansur Nassiri Koopaei | Homa Azizian | Zahra Mousavi | Ali Almasirad | Mona Salimi
Source: BMC Chemistry (article, 2022-11-01)
Field: Chemistry — Organic Chemistry

Design and synthesis of novel ureido and thioureido conjugated hydrazone derivatives with potent anticancer activity The compounds were synthesized and then characterized by physical and spectral data (FT-IR, <sup>1</sup>H-NMR, <sup>13</sup>C-NMR, Mass). The anticancer activity was assessed using MTT assay, flowcytometry, annexin-V, DAPI staining and Western blot analysis. Hydrazone ; Chemistry ; Moiety ; Stereochemistry ; Chalcone ; DAPI ; MTT assay ; Apoptosis ; Thiourea ; Combinatorial chemistry ; Biochemistry ; Organic chemistry Synthesis and biological activity ; Enzyme function and inhibition ; Synthesis and Characterization of Heterocyclic Compounds
Authors: Francesco Bisiak | Adriana Chrenková | Sheng‐Da Zhang | Jannik Nedergaard Pedersen | Daniel E. Otzen | Yong Everett Zhang | Ditlev E. Brodersen
Source: Journal of Biological Chemistry (article, 2022-06-14)
Field: Materials Science — Materials Chemistry

Structural variations between small alarmone hydrolase dimers support different modes of regulation of the stringent response The bacterial stringent response involves wide-ranging metabolic reprogramming aimed at increasing long-term survivability during stress conditions. One of the hallmarks of the stringent response is the production of a set of modified nucleotides, known as alarmones, which affect a multitude of cellular pathways in diverse ways. Production and degradation of these molecules depend on the activity of enzymes from the RelA/SpoT homologous family, which come in both bifunctional (containing domains to both synthesize and hydrolyze alarmones) and monofunctional (consisting of only synthetase or hydrolase domain) variants, of which the structure, activity, and regulation of the bifunctional RelA/SpoT homologs have been studied most intensely. Despite playing an important role in guanosine nucleotide homeostasis in particular, mechanisms of regulation of the small alarmone hydrolases (SAHs) are still rather unclear. Here, we present crystal structures of SAH enzymes from Corynebacterium glutamicum (RelH<sub>Cg</sub>) and Leptospira levettii (RelH<sub>Ll</sub>) and show that while being highly similar, structural differences in substrate access and dimer conformations might be important for regulating their activity. We propose that a varied dimer form is a general property of the SAH family, based on current structural information as well as prediction models for this class of enzymes. Finally, subtle structural variations between monofunctional and bifunctional enzymes point to how these different classes of enzymes are regulated. Stringent response ; Hydrolase ; Chemistry ; Biology ; Stereochemistry ; Biochemistry ; Enzyme ; Escherichia coli ; Gene Enzyme Structure and Function ; Biochemical effects in animals ; Biochemical Acid Research Studies