jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Federico Caporaletti | S. Capaccioli | Dimitrios Bessas | Aleksander I. Chumakov | Alessandro Martinelli | G. Monaco
Source: Journal of Molecular Liquids (article, 2023-05-16)
Field: Materials Science — Materials Chemistry

Microscopic investigation of the Johari-Goldstein relaxation in cumene: Insights on the mosaic structure in a van der Waals liquid The Johari-Goldstein (βJG) relaxation anticipates in time, and is closely connected to, the structural relaxation in deeply supercooled liquids. Probing its microscopic properties is a crucial step for a complete understanding of the glass-transition. We here report the investigation of the van der Waals glass-former cumene using time-domain interferometry, a technique able to probe microscopic density fluctuations at the spatial and temporal scales relevant for the βJG-relaxation. We find that the molecules participating in it undergo a restricted motion, though sufficient to induce local, cage-breaking events at the characteristic time-scale for molecular re-orientations. A detailed characterization of the relaxation strength, i.e. the fraction of molecules involved in the relaxation process, shows that such molecules are connected in a percolating cluster which, above the glass-transition temperature, Tg, is weakly dependent on temperature. Our results confirm thus previous observations of a mosaic structure associated to the βJG-relaxation in the supercooled state, and provide additional information on its temperature evolution above the glass-transition temperature. We conclude that the observed microscopic properties of the βJG-relaxation, and thus of the associated mosaic structure, are generic and independent of the molecular interaction potential. In addition, we show that, while the dynamics within the percolating cluster becomes progressively slower on approaching Tg, the fraction of the molecules involved in cage-breaking events within the βJG-relaxation is not affected by temperature. Supercooling ; Relaxation (psychology) ; Glass transition ; van der Waals force ; Chemical physics ; Cluster (spacecraft) ; Cumene ; Nucleation ; Molecule ; Characterization (materials science) ; Molecular dynamics ; Chemistry ; Materials science ; Thermodynamics ; Physics ; Computational chemistry ; Nanotechnology ; Polymer ; Organic chemistry Material Dynamics and Properties ; Glass properties and applications ; High-pressure geophysics and materials
Authors: Theresa Hennig | Michael Kühn
Source: Advances in geosciences (article, 2023-10-18)
Field: Chemistry — Inorganic Chemistry

Uranium migration lengths in Opalinus Clay depend on geochemical gradients, radionuclide source term concentration and pore water composition Abstract. Safety assessments of highly radioactive waste disposal sites are done based on simulation of radionuclide migration lengths through the containment providing rock zone. For a close to real case situation, the present model concept established for uranium is derived from the hydrogeological evolution and geochemical and mineralogical data measured at the deep geothermal borehole Schlattingen including the effect of geo-engineered barriers on the source term. In the Schlattingen area, the Opalinus Clay is tectonically undeformed compared to the Mont Terri anticline and represents the geochemical and temperature conditions at the favoured disposal depth. The geochemical conditions are more or less constant with slightly decreasing concentrations of pore water components towards the footwall aquifer. Uranium migrates less compared to the Opalinus Clay system at Mont Terri, where gradients of pore water geochemistry towards the embedding aquifers are more pronounced. This means, stable geochemical conditions with no or low concentration gradients are to be favoured for a safe disposal since migration lengths strongly depend on spatial and temporal variation of the hydrogeological and geochemical conditions within the host formation. The engineered barriers reduce the source term concentration what, in turn, is associated with a decrease in uranium migration. Stable geochemical conditions further enable the application of the Kd approach to estimate the impact of the barriers. The hydrogeological system must always be considered when quantifying radionuclide migration. Aquifer ; Geology ; Uranium ; Hydrogeology ; Radionuclide ; Geochemistry ; Pore water pressure ; Groundwater ; Radioactive waste ; Borehole ; Mineralogy ; Geotechnical engineering ; Chemistry Radioactive element chemistry and processing ; Groundwater flow and contamination studies ; Radioactivity and Radon Measurements
Authors: Yeongjun Seo | Shengfang Shi | Tomoyo Goto | Sunghun Cho | Tohru Sekino
Source: Discover Materials (article, 2023-05-30)
Field: Materials Science — Ceramics and Composites

Structure-property correlation of alumina/nickel composites for their mechanical and electrical properties Abstract Al 2 O 3 /nickel (Ni) composites were fabricated via hot-press sintering at 1400 °C to investigate the effects of microstructure on their mechanical and electrical properties. For this purpose, various amounts of Ni metal particles (5–20 vol%) were dispersed in Al 2 O 3 ceramics. All the composites were highly densified, with a theoretical density of over 97%, and microstructural observations revealed elongated Ni phases and strong Al 2 O 3 /Ni interfaces. The Young’s moduli of the composites with 5–15 vol% Ni content were higher than that of the pure Al 2 O 3 matrix. Additionally, all the composites showed higher fracture toughness than the pure Al 2 O 3 ceramic matrix, owing to toughening mechanisms such as crack deflection and bridging between Al 2 O 3 grains. This microstructural evolution also affected the formation of continuous conductive pathways connecting the elongated Ni particles. As a result, the electrical resistivity of the composite dramatically decreased to 3.6 × 10 3 Ωcm at 15 vol% Ni and was further reduced to 1.1 × 10 2 Ωcm when the volume fraction of Ni was increased to 20 vol%. These results suggest that controlling the amount of Ni, which greatly affects the microstructural evolution, can simultaneously enhance the mechanical and electrical properties of Al 2 O 3 /Ni composites. Materials science ; Composite material ; Microstructure ; Composite number ; Ceramic ; Nickel ; Electrical resistivity and conductivity ; Volume fraction ; Fracture toughness ; Sintering ; Metallurgy Advanced ceramic materials synthesis ; Aluminum Alloys Composites Properties ; Thermal properties of materials
Authors: A. Carpio | Gema Duro
Source: Applied Mathematical Modelling (article, 2023-07-07)
Field: Materials Science — Surfaces, Coatings and Films

Well posedness of fluid-solid mixture models for biofilm spread Boundary (topology) ; Boundary value problem ; Biofilm ; Diffusion ; Set (abstract data type) ; Stability (learning theory) ; Mathematics ; Motion (physics) ; Applied mathematics ; Biological system ; Mechanics ; Statistical physics ; Mathematical analysis ; Computer science ; Physics ; Classical mechanics ; Thermodynamics ; Geology Polymer Surface Interaction Studies ; Blood properties and coagulation ; 3D Printing in Biomedical Research
Authors: Chen Wang | Xi Kong | Xiaoyu Mao | Chen Chen | Pei Yu | Ya Wang | Fazhan Shi | Jiangfeng Du | Ming Gong | Hualing Zeng
Source: Communications Physics (article, 2023-12-05)
Field: Materials Science — Materials Chemistry

Thermal-activated escape of the bistable magnetic states in 2D Fe3GeTe2 near the critical point Abstract Great effort has been made recently to investigate the phase transitions in two-dimensional (2D) magnets while leaving subtle quantification unsolved. Here, we demonstrate the thermal-activated escape in 2D Fe 3 GeTe 2 ferromagnets near the critical point with a quantum magnetometry based on nitrogen-vacancy centers. We observe random switching between the two spin states with auto-correlation time described by the Arrhenius law, where a change of temperature by 0.8 K induces a change of lifetime by three orders of magnitude. Moreover, a large energy difference between the two spin states about 51.3 meV is achieved by a weak out-of-plane magnetic field of 1 G, yielding occupation probability described by Boltzmann’s law. Using these data, we identify all the parameters in the Ginzburg-Landau model. This work provides quantitative description of the phase transition in 2D magnets, which paves the way for investigating the critical fluctuation and even non-equilibrium phase transitions in these 2D materials. Condensed matter physics ; Ferromagnetism ; Physics ; Bistability ; Magnetic field ; Phase transition ; Magnet ; Magnetometer ; Spin (aerodynamics) ; Critical point (mathematics) ; Thermal ; Work (physics) ; Phase (matter) ; Quantum mechanics ; Thermodynamics Graphene research and applications ; Quantum and electron transport phenomena ; 2D Materials and Applications
Authors: Peter Gogola | Zuzana Gabalcová | Martin Kusý | Jana Ptačinová
Source: Materials (article, 2023-04-24)
Field: Materials Science — Materials Chemistry

High-Temperature Behaviour of Zn-Based Galvannealed Coatings on Steel The potential of using a Zn-based, hot-dip coating to limit steel scale formation was investigated. The phase evolution within a pure Zn and a Zn0.1Al coating on a medium-carbon (0.5 wt.% C, 0.25 wt.% Si) steel sheet during a series of heat treatment steps was investigated. Such Zn-based coatings react with the steel substrate depending on the actual heat treatment condition. A series of expected intermetallic phases was observed via SEM/EDX and XRD techniques, such as ζ, δ and Γ phases along the η(Zn) phase. The η(Zn) phase was transformed to mainly δ and Γ phases during galvannealing (500 °C). The rapid quenching from 850 °C enabled the formation of the supersaturated α-(Fe) solid solution with increased Zn content. A continuous, intact, ~20 µm thick coating was observed after the final step of the heat treatment procedure, while signs of liquid metal embrittlement (LME) were not observed near the coating/steel interface. This will ensure reliable protection against heavy scale formation on heat-treated steel parts. Materials science ; Galvannealed ; Coating ; Quenching (fluorescence) ; Intermetallic ; Metallurgy ; Carbon steel ; Phase (matter) ; Embrittlement ; Supersaturation ; Substrate (aquarium) ; Heat treating ; Galvanization ; Composite material ; Corrosion ; Layer (electronics) Corrosion Behavior and Inhibition ; Metal and Thin Film Mechanics ; Hydrogen embrittlement and corrosion behaviors in metals
Authors: Xi Guo | Xianzhi Yang | Di Wang | Dong Li | Yushuang Li | Yu Pu | Yan Lv | Hanbing Qi
Source: Heliyon (article, 2023-08-27)
Field: Chemistry — Spectroscopy

Identification of ground spilled oil of buried pipeline based on laser absorption spectroscopy: Numerical investigation and experimental verification The ground diffusion characteristics of buried oil pipeline after leakage and the laser optical transmission mechanism of surface oil film are the basis of spectral detection technology. Based on the computational fluid dynamics to solve the diffusion equation of multiphase flow in porous media, the leakage law of oil under different soil porosity is analyzed in two dimensions: surface diffusion diameter and oil film thickness. TracePro optical simulation is used to study the absorption and reflection patterns of laser at the oil-gas interface, and validation experiments are carried out based on the tunable diode laser absorption spectroscopy method. The results show that oil is easily accumulated on the ground surface with larger soil porosity and in the depressions of the ground surface. When the oil film thickness is greater than 2 mm, the laser cannot transmit the oil layer and the received light intensity is only provided by the mirror reflection at the oil-gas interface. The mechanism of laser detection of oil leaks is the spectral absorption of volatile alkane gases in the upper layer of the oil film by a laser of a specific wavelength. Materials science ; Laser ; Absorption (acoustics) ; Porous medium ; Optics ; Leakage (economics) ; Spectroscopy ; Reflection (computer programming) ; Porosity ; Wavelength ; Optoelectronics ; Composite material Spectroscopy and Laser Applications ; Atmospheric and Environmental Gas Dynamics ; Water Quality Monitoring and Analysis
Authors: Zhifang Wei | Xin Chang-fan | Xiucheng Hou | Yanfei Su | Fangzhou Wang
Source: Propellants Explosives Pyrotechnics (article, 2023-03-09)
Field: Materials Science — Materials Chemistry

Mechanical–thermal–chemical coupled modeling techniques and numerical simulation methods for the firearm igniting process Abstract The firing and ignition of firearms is a complex process involving the coupled effects of mechanical, thermal, and chemical mechanisms. The theoretical modeling and numerical simulation methods for primer mixture impact and ignition process are investigated to reveal the response patterns of characteristic variables, such as primer output pressure and the crater on the primer cup that forms when the firing pin strikes the primer to ignite the primer mixture. Theoretical models such as the elastoplastic mechanical response of the primer mixture, the pore collapse hot spot model, and the Lee‐Tarver ignition and growth model are established by studying the impact response, the initiation mechanism, the hot spot formation mechanism, and the energy release mechanism of the primer mixture. Constitutive models of the primer mixture and the primer cup material are established based on a dynamic compression test of the primer mixture under passive confining pressure and a quasi‐static tensile test of the primer cup material. A numerical model of the primer mixture impact and ignition performance is constructed by using ANSYS LS‐DYNA software. The simulation parameters are serially simulated and calibrated through the 3D total Lagrange algorithm. The firing and ignition response process of a small‐caliber firearm is simulated with the 3D Activation Likelihood Estimation (ALE) algorithm. The relative error between the simulated results and the test results is below 15 %, which validates the feasibility of the numerical simulation methods for the firing and ignition performances of firearms. Ignition system ; Primer (cosmetics) ; Computer simulation ; Materials science ; Hot spot (computer programming) ; Process (computing) ; Mechanics ; Structural engineering ; Engineering ; Simulation ; Computer science ; Thermodynamics ; Physics ; Aerospace engineering High-Velocity Impact and Material Behavior ; Energetic Materials and Combustion ; Electromagnetic Launch and Propulsion Technology
Authors: Vahid A. Hosseini | Mattias Thuvander | Kristina Lindgren | James Oliver | Nicklas Folkeson | Daniel Gonzalez | Sezgin Cengiz | Leif Karlsson
Source: steel research international (article, 2023-09-08)
Field: Materials Science — Metals and Alloys

Influence of Fabrication Route and Copper Content on Nature and Kinetics of 475 °C‐ Embrittlement in Cu‐Containing Super Duplex Stainless Steels The influence of hot‐rolling, hot isostatic pressing (HIP), welding, as well as copper content on 475 °C‐embrittlement is studied in super duplex stainless steels. The as‐received samples are solution annealed and quenched. Then, to study the kinetics and nature of phase transformations during fabrication, the samples are aged for a very short duration of 5 min at 475 °C. Atom probe tomography results reveal that the processes involving more plastic deformation such as hot rolling and HIP accelerate chromium and iron phase separation and cause precipitation of copper‐rich particles (CRPs) in ferrite, resulting in significant toughness loss. In contrast, the weld does not show a high level of chromium and iron phase separation or CRPs precipitation, preserving its toughness after the short aging. The experiment and the inverse interdiffusion calculations reveal that raising the copper content slow down chromium and iron phase separation but significantly increase the CRP number density and decrease the toughness of the HIPed material. Precipitation simulation of CPRs show that the model must be modified based on each processing condition. It is concluded that hot rolling and HIP accelerate 475 °C‐embrittlement, which cannot be prevented by raising the copper content. Materials science ; Metallurgy ; Embrittlement ; Copper ; Hot isostatic pressing ; Chromium ; Austenite ; Toughness ; Precipitation ; Welding ; Duplex (building) ; Ferrite (magnet) ; Composite material ; Microstructure Hydrogen embrittlement and corrosion behaviors in metals ; Microstructure and Mechanical Properties of Steels ; High Temperature Alloys and Creep
Authors: Arun Raina | V.S. Deshpande | Emilio Martínez‐Pañeda | N.A. Fleck
Source: Continuum Mechanics and Thermodynamics (article, 2023-06-25)
Field: Materials Science — Metals and Alloys

Analysis of hydrogen diffusion in the three stage electro-permeation test Abstract The presence of hydrogen traps within a metallic alloy influences the rate of hydrogen diffusion. The electro-permeation (EP) test can be used to assess this: the permeation of hydrogen through a thin metallic sheet is measured by suitable control of hydrogen concentration on the front face and by recording the flux of hydrogen that exits the rear face. Additional insight is achieved by the more sophisticated three stage EP test: the concentration of free lattice hydrogen on the front face is set to an initial level, is then dropped to a lower intermediate value and is then restored to the initial level. The flux of hydrogen exiting the rear face is measured in all three stages of the test. In the present study, a transient analysis is performed of hydrogen permeation in a three stage EP test, assuming that lattice diffusion is accompanied by trapping and de-trapping. The sensitivity of the three stage EP response to the depth and density of hydrogen traps is quantified. A significant difference in permeation response can exist between the first and third stages of the EP test when the alloy contains a high number density of deep traps. Hydrogen ; Permeation ; Materials science ; Trapping ; Diffusion ; Lattice (music) ; Analytical Chemistry (journal) ; Chemistry ; Thermodynamics ; Chromatography ; Physics ; Organic chemistry Hydrogen embrittlement and corrosion behaviors in metals ; Corrosion Behavior and Inhibition ; Metal and Thin Film Mechanics
Authors: Bo You
Source: Mathematical Control and Related Fields (article, 2023-06-30)
Field: Materials Science — Materials Chemistry

Optimal distributed control for a Cahn-Hilliard type phase field system related to tumor growth The main objective of this paper is to consider an optimal distributed control problem for a Cahn-Hilliard type phase field system related to tumor growth, which consists of Cahn-Hilliard equation with two relaxation terms and a reaction-diffusion equation with a suitable distributed control variable representing the concentration of cytotoxic drugs in medical treatment. We prove the well-posedness of the state system and its corresponding linearized system. Based on these results, we establish the Fréchet differentiability of the control-to-state operator and deduce the first-order necessary optimality conditions in terms of a variational inequality involving the adjoint state variables. Moreover, by establishing some a priori estimates that are uniform in some relaxation parameter, we implement the asymptotical analysis of the solutions as well as the optimal control when the relaxation parameter approaches to zero. Differentiable function ; Mathematics ; Optimal control ; Operator (biology) ; Relaxation (psychology) ; Type (biology) ; Variational inequality ; A priori and a posteriori ; Cahn–Hilliard equation ; Applied mathematics ; Control variable ; State variable ; Variable (mathematics) ; State (computer science) ; Mathematical optimization ; Mathematical analysis ; Physics ; Algorithm ; Thermodynamics ; Chemistry Solidification and crystal growth phenomena ; Advanced Mathematical Modeling in Engineering ; Mathematical Biology Tumor Growth
Authors: Michael Regev | Alberto Santoni | S. Spigarelli
Source: Metals (article, 2023-07-15)
Field: Materials Science — Materials Chemistry

Oxidation Effects on Short-Term Creep Response in Air of Commercially Pure Titanium (CP-2 Ti) The creep response in the air of commercially pure titanium was investigated at 550, 600, and 650 °C to assess the effect of oxidation on the mechanical response. Experiments demonstrated that prolonged exposures at high temperatures produced a marked reduction in the minimum creep rate under a given applied stress. Microhardness measurements showed that a hardened zone formed in proximity to the surface due to oxygen penetration into the metal. A simplified composite model was then used to describe the creep response. In this model, the sample consisted of two zones, the hard case that was enriched in oxygen and the soft pure-titanium core, both creeping with similar strain rates. Calculations led to an estimation of the dependence of the minimum creep rate on stress and temperature for the hard high-oxygen zone. The simplified composite model presented here provided a good description of the experimental creep data for pure titanium, tested in its air, and a reliable picture of the effect of oxidation on complex Ti alloys. Creep ; Materials science ; Titanium ; Composite number ; Oxygen ; Metallurgy ; Indentation hardness ; Metal ; Composite material ; Oxide ; Microstructure ; Chemistry Titanium Alloys Microstructure and Properties ; Nuclear Materials and Properties ; Intermetallics and Advanced Alloy Properties
Authors: Jiyaul Hak | Amit Aggarwal - | Sandeep Kumar - | Arvinder Pal Singh - | Anshi Kumari -
Source: International Journal For Multidisciplinary Research (review, 2023-04-26)
Field: Chemistry — Organic Chemistry

Study on Benzimidazole: A Comprehensive Review The chemical compound known as benzimidazole has been assigned to the category of heterocyclic aromatic in one of the potential classifications for it. This structure has a notable pharmacophore position in the scientific discipline of medicinal chemistry and enjoys a privileged status within that discipline. As a result of the fact that it possesses a wide range of beneficial therapeutic effects, such as those of antiulcerants, antihypertensives, analgesics, edicines, antivirals, antifungals, anticancer, and antihistamines, it serves a very important purpose. This is due to the fact that it has a very important purpose. The literature review reveals that benzimidazole derivatives are effective chemicals, and a wide range of reviews that are currently available on the market for organic chemistry and medical specialist studies have confirmed that the molecules of these compounds are helpful against a variety of different microorganisms. The importance of the methodology used in its synthesis has piqued the curiosity of synthetic organic chemists, who have shown an interest in the processes involved. As a direct result of this, we have made an effort in our evaluation of the gift to assemble information on the chemistry that lies behind a wide variety of substituted benzimidazole byproducts and the many medicinal applications of these substances. Benzimidazole ; Pharmacophore ; Chemistry ; Variety (cybernetics) ; Biochemical engineering ; Combinatorial chemistry ; Nanotechnology ; Computer science ; Organic chemistry ; Stereochemistry ; Engineering ; Materials science Synthesis and biological activity ; Computational Drug Discovery Methods