jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Sergei V. Kalinin | Ayana Ghosh | Rama K. Vasudevan | Maxim Ziatdinov
Source: arXiv (Cornell University) (preprint, 2021-09-15)
Field: Materials Science — Materials Chemistry

Describing condensed matter from atomically resolved imaging data: from structure to generative and causal models The development of high-resolution imaging methods such as electron and scanning probe microscopy and atomic probe tomography have provided a wealth of information on structure and functionalities of solids. The availability of this data in turn necessitates development of approaches to derive quantitative physical information, much like the development of scattering methods in the early XX century which have given one of the most powerful tools in condensed matter physics arsenal. Here, we argue that this transition requires adapting classical macroscopic definitions, that can in turn enable fundamentally new opportunities in understanding physics and chemistry. For example, many macroscopic definitions such as symmetry can be introduced locally only in a Bayesian sense, balancing the prior knowledge of materials' physics and experimental data to yield posterior probability distributions. At the same time, a wealth of local data allows fundamentally new approaches for the description of solids based on construction of statistical and physical generative models, akin to Ginzburg-Landau thermodynamic models. Finally, we note that availability of observational data opens pathways towards exploring causal mechanisms underpinning solid structure and functionality. Generative grammar ; Statistical physics ; Data science ; Generative model ; Computer science ; Theoretical physics ; Physics ; Artificial intelligence ; Nanotechnology ; Materials science Machine Learning in Materials Science ; Advanced Electron Microscopy Techniques and Applications ; Force Microscopy Techniques and Applications
Authors: Prateek Sharma | Stefan Diebels
Source:  (article, 2021-01-01)
Field: Materials Science — Polymers and Plastics

Moisture Transport In Polyamide (PA6) and Its Effect On the Mechanical Behaviour Polyamide exhibits hygroscopic nature and can absorb up to 10 % of moisture relative to its weight. The absorbed moisture increases the mobility of the molecular chains and causes a reduction in the glass transition temperature. Thus, depending on the moisture distribution, a polyamide component can show different stiffness and relaxation times. The moisture distribution also depends on the mechanical loading of the material. However, it was noticed that the diffusion process remains unaffected when the process is compared for a loaded and an unloaded material. It is postulated that the moisture redistribution is due to an external force that takes place as a result of the pressure acting on the moisture. The diffusion process is unaffected by preloading of the dry material as the pressure is applied purely on the material and not on the absorbed moisture. However, when a saturated specimen is loaded, the pressure is exerted on the moisture too which causes its redistribution. In this work, the distribution of the absorbed moisture is simulated by a non-linear diffusion model. It is coupled with the viscoelastic behaviour of PA6. The stiffness of the viscoelastic model changes and the relaxation time reduces with increasing moisture concentration. The coupling of diffusion to mechanical loading is achieved with the recalculation of the moisture concentration caused due to the redistribution of volume. It is assumed that there is no transport of moisture, but the transport of volume and the change in volume creates a change in concentration in the specimen. This strongly coupled model has been implemented using the finite element method. The model results are compared to experiments for validation. A strongly coupled model was thus created which could reproduce the experimental results with reasonable accuracy. Moisture ; Materials science ; Viscoelasticity ; Composite material ; Polyamide ; Volume (thermodynamics) ; Diffusion ; Redistribution (election) ; Relaxation (psychology) ; Thermodynamics Polymer crystallization and properties ; Material Properties and Processing ; Mechanical Behavior of Composites
Authors: Samir Kumar | Taneichi Taiga | Kyoto Namura | Takao Fukuoka | Motofumi Suzuki
Source: Research Square (preprint, 2021-07-02)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Study on Transport of Molecules in Gel by Surface-Enhanced Raman Spectroscopy Abstract Surface-enhanced Raman spectroscopy (SERS)-based biosensors have recently been extensively developed because of their high sensitivity and non-destructive nature. Conventional SERS substrates are unsuitable for detecting biomolecules directly from human skin. As a result, significant effort is being put into developing a gel-type SERS sensor that can segregate and detect biomolecules due to differences in molecular transport phenomena in the gel. However, no comprehensive research studies on the transport processes of molecules in gels in gel-type SERS sensors have been reported. This paper reports the differences in the transport phenomena of different molecules based on the time change of SERS spectrum intensity. The Au nanorod array substrate was coated with HEC gel to prepare a sample cell to study diffusion. The SERS spectra of aqueous solutions of 9 types of molecules were measured using the prepared sample cells. The rate at which each molecule diffuses into the gel differs depending on the molecule. The time variation of the characteristic SERS peak of each molecule was investigated based on a one-dimensional diffusion model, and the diffusion coefficient D was calculated for each molecule. A comparative study was conducted on the relationship between the diffusion coefficient and the molecular weight and molecular size, and it was found that the larger the molecular weight and molecular size, the slower the diffusion, which is based on the molecular motion theory and the inhibitory effect of the gel substance. Biomolecule ; Molecule ; Diffusion ; Raman spectroscopy ; Chemistry ; Molecular diffusion ; Surface-enhanced Raman spectroscopy ; Analytical Chemistry (journal) ; Nanotechnology ; Materials science ; Chemical physics ; Chromatography ; Raman scattering ; Organic chemistry ; Optics Gold and Silver Nanoparticles Synthesis and Applications ; Spectroscopy Techniques in Biomedical and Chemical Research ; Advancements in Transdermal Drug Delivery
Authors: Xiaoning Kang | Lulu Kang | Wei Chen | Xinwei Deng
Source: arXiv (Cornell University) (preprint, 2021-02-18)
Field: Materials Science — Materials Chemistry

A Generative Approach to Joint Modeling of Quantitative and Qualitative Responses In many scientific areas, data with quantitative and qualitative (QQ) responses are commonly encountered with a large number of predictors. By exploring the association between QQ responses, existing approaches often consider a joint model of QQ responses given the predictor variables. However, the dependency among predictive variables also provides useful information for modeling QQ responses. In this work, we propose a generative approach to model the joint distribution of the QQ responses and predictors. The proposed generative model provides efficient parameter estimation under a penalized likelihood framework. It achieves accurate classification for qualitative response and accurate prediction for quantitative response with efficient computation. Because of the generative approach framework, the asymptotic optimality of classification and prediction of the proposed method can be established under some regularity conditions. The performance of the proposed method is examined through simulations and real case studies in material science and genetics. Generative grammar ; Computer science ; Dependency (UML) ; Generative model ; Joint probability distribution ; Machine learning ; Computation ; Joint (building) ; Artificial intelligence ; Data mining ; Mathematics ; Algorithm ; Statistics ; Engineering Machine Learning in Materials Science ; Advanced Multi-Objective Optimization Algorithms ; Optimal Experimental Design Methods
Authors: P. K. Galenko | He, Miao | Salhoumi, Ahmed | Zhigilei, Leonid V. | Galenko, Peter K.
Source: Figshare (article, 2021-01-01)
Field: Materials Science — Materials Chemistry

Supplementary material from "Kinetics of solid–liquid interface motion in molecular dynamics and phase-field model: crystallization of chromium and silicon" The results of molecular dynamics (MD) simulations of the crystallization process in one-component materials and solid solution alloys reveal a complex temperature dependence of the velocity of the crystal–liquid interface featuring an increase up to a maximum at 10–30% undercooling below the equilibrium melting temperature followed by a gradual decrease of the velocity at deeper levels of undercooling. At the qualitative level, such non-monotonous behaviour of the crystallization front velocity is consistent with the diffusion-controlled crystallization process described by the Wilson–Frenkel model, where the almost linear increase of the interface velocity in the vicinity of melting temperature is defined by the growth of the thermodynamic driving force for the phase transformation, while the decrease in atomic mobility with further increase of the undercooling drives the velocity though the maximum and into a gradual decrease at lower temperatures. At the quantitative level, however, the diffusional model fails to describe the results of MD simulations in the whole range of temperatures with a single set of parameters for some of the model materials. The limited ability of the existing theoretical models to adequately describe the MD results is illustrated in the present work for two materials, chromium and silicon. It is also demonstrated that the MD results can be well described by the solution following from the hodograph equation, previously found from the phase-field model (PFM) in the sharp interface limit. The ability of the hodograph equation to describe the predictions of MD simulation in the whole range of temperatures is related to the introduction of slow (phase field) and fast (gradient flow) variables into the original kinetic PFM from which the hodograph equation obtained. The slow phase-field variable is responsible for the description of data at small undercoolings and the fast gradient flow variable accounts for local non-equilibrium effects at high undercoolings. The introduction of these two types of variables makes the solution of the hodograph equation sufficiently flexible for a reliable description of all nonlinearities of the kinetic curves predicted in MD simulations of Cr and Si.This article is part of the theme issue ‘Transport phenomena in complex systems (Part 1)’. Crystallization ; Silicon ; Kinetics ; Materials science ; Chromium ; Phase (matter) ; Field (mathematics) ; Molecular dynamics ; Dynamics (music) ; Interface (matter) ; Chemical physics ; Thermodynamics ; Chemical engineering ; Chemistry ; Metallurgy ; Physics ; Classical mechanics ; Composite material ; Wetting ; Computational chemistry ; Engineering ; Mathematics ; Organic chemistry Solidification and crystal growth phenomena
Authors: Miljana Radović Vučić | Jelena Mitrović | Miloš Kostić | Nena Velinov | Milica Petrović | Danijela Bojić | Aleksandar Bojić
Source:  (article, 2021-02-23)
Field: Materials Science — Materials Chemistry

Ultra-violet responsive photocatalytic application of CuO/Bi oxide nitrate hydroxide hydrate powder A new photocatalyst CuO/Bi oxide nitrate hydroxide hydrate (C-BONH) has been synthesized by hydrothermal method. The obtained product has been characterized using x-rays diffraction (XRD), fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The surface area has been measured by Brunauer-Emmett-Teller (BET) method, and it has been found 4.42 m 2 g –1 . The photocatalytic activity has been evaluated by removal of reactive blue 19 (RB 19) dye, where total decolorization has been achieved in less than 15 minutes. The photocatalytic process is described with four kinetic models (Langmuir‒Hinshelwood model, pseudo-first order kinetic model, pseudo-second order kinetic model and Chrastil diffusion model). Langmuir‒Hinshelwood kinetic model and pseudo-first order kinetic model the best describe the photocatalytic process. Chrastil diffusion model has been shown that diffusion has not any influence on the process. The chemical oxygen demand (COD) has been decreased from 28.1 to 6.82 mg dm –3 within 180 minusing UV light (254 nm wavelength). It has been observed that photocatalyst retained its stability and activity even after five cycles, which could significantly reduce the operation cost in practical applications. Photocatalysis ; Hydroxide ; Fourier transform infrared spectroscopy ; Scanning electron microscope ; Hydrate ; Chemistry ; Diffusion ; Nuclear chemistry ; Inorganic chemistry ; Materials science ; Analytical Chemistry (journal) ; Chemical engineering ; Catalysis ; Organic chemistry Copper-based nanomaterials and applications
Authors: Ewa Karchniwy | Sławomir Sładek | Adam Klimanek | Andrzej Szlęk | Agnieszka Korus | Wojciech Adamczyk
Source: Proceedings of the World Congress on Mechanical, Chemical, and Material Engineering (article, 2021-08-01)
Field: Materials Science — Materials Chemistry

Influence of Surface Temperature Distribution on Reaction Rateof Solid Fuel Char Particles In the paper the effect of surface temperature distribution on the reaction rate and conversion of char particles is investigated. The distribution of temperature at reacting char particles was observed experimentally and was attributed to the non-uniformity of chemical composition, porosity and shape of particles. Based on the measured temperature variation, the influence of the temperature non-uniformity on reaction rate at the particle surface was investigated analytically and numerically using a kinetic-diffusion model. It was found that the temperature non-uniformity translates into reaction rate variation with a temperature dependent standard deviation that has two extrema in the considered temperature range. However, the minimum lies in the region of high temperatures, where the bulk diffusion resistance limits the reaction rate. The effect was also investigated during combustion of char particles in a CFD model of a simple combustion chamber. It was shown that the non-uniform temperature has small but noticeable influence on mean reaction rate and particle conversion, leading to a larger distribution of conversion of solid fuel particles. Char ; Materials science ; Solid fuel ; Solid surface ; Chemical engineering ; Distribution (mathematics) ; Nuclear engineering ; Chemistry ; Pyrolysis ; Chemical physics ; Combustion ; Physical chemistry ; Engineering ; Mathematics Catalytic Processes in Materials Science ; Biodiesel Production and Applications ; Thermochemical Biomass Conversion Processes
Authors: Lovasoa Rakotondramasy-Rabesiaka | Lantonisa H. Rakotonirina | Mihasina Rabesiaka | Amélie Raharisololalao
Source:  (article, 2021-01-01)
Field: Chemistry — Spectroscopy

Modeling of Solid-liquid Extraction of Water-Solubles from Salvia Coccinea (Lamiacea) The aim of this study is to establish models to describe and explain the transfer phenomena of water-soluble solutes in a solid phase plant to a liquid phase (water). These are the leaves and stems of Salvia coccinea. The approach consists of a model establishment to simulate the kinetics of a solid-liquid extraction. Three models were used. The Mafarat and Beliard I, II and pseudo-diffusion models define the overall material transfer coefficients and the solutes concentration of the liquid phase. The Spiro and Kandiah model determines the two time constants corresponding to the diffusion of localized solutes in broken-wall and intact-wall cells, the amount of solutes fraction in broken-wall cells, and the solute concentration. The pseudo-second order kinetic model determines the kinetic constant of extraction and the extraction capacity. Comparing the results of the simulations with the experimental measurements indicates that the models satisfactorily represent the evolution of the extraction operation and that the transfer is divided into two stages, a fast first step consisting of diffusion and a slow step which is a sum of various phenomena. Extraction (chemistry) ; Diffusion ; Phase (matter) ; Kinetic energy ; Mass transfer ; Kinetics ; Materials science ; Thermodynamics ; Chemistry ; Fick's laws of diffusion ; Constant (computer programming) ; Chromatography ; Organic chemistry ; Physics Analytical Chemistry and Chromatography
Authors: Jingbo Ni | Ruyi Liu | Changhao Yan
Source: Desalination and Water Treatment (article, 2021-06-01)
Field: Chemistry — Inorganic Chemistry

Removal and recovery of uranium(VI) from aqueous solution by adsorption of surface aldehyde assembled polystyrene microspheres Adsorption ; Aqueous solution ; Chemistry ; Ionic strength ; Uranium ; Sorption ; Nuclear chemistry ; Polystyrene ; Zeta potential ; Uranyl ; Inorganic chemistry ; Chemical engineering ; Organic chemistry ; Materials science ; Ion ; Nanoparticle Radioactive element chemistry and processing ; Chemical Synthesis and Characterization ; Extraction and Separation Processes
Authors: Giovanni Nastasi | Vittorio Romano
Source: IEEE Transactions on Electron Devices (preprint, 2021-07-26)
Field: Materials Science — Materials Chemistry

An Efficient GFET Structure A graphene FET (GFET), where the active area is made of monolayer large-area graphene, is simulated including a full 2-D Poisson equation and a drift-diffusion model with mobilities deduced by a direct numerical solution of the semiclassical Boltzmann equations for charge transport by a suitable discontinuous Galerkin approach. The critical issue in a GFET is the difficulty of fixing the OFF state which requires an accurate calibration of the gate voltages. In this article, we propose and simulate a GFET structure which has well-behaved characteristic curves similar to those of conventional (with gap) semiconductor materials. The introduced device has a clear off region and can be the prototype of devices suited for postsilicon nanoscale electron technology. The specific geometry overcomes the problems of triggering the minority charge current and gives a viable way for the design of electron devices based on large area monolayer graphene as a substitute of standard semiconductors in the active area. The good FET behavior of the current versus the gate voltage makes the simulated device very promising and a challenging case for experimentalists, even if it is crucial to better understand the resistance effect of charge carriers at the contact-graphene region. Transistor ; Graphene ; Materials science ; Field-effect transistor ; Semiclassical physics ; Semiconductor ; Monolayer ; Voltage ; Silicon ; Optoelectronics ; Poisson's equation ; Nanotechnology ; Physics ; Quantum ; Quantum mechanics Graphene research and applications ; Quantum and electron transport phenomena ; Advancements in Semiconductor Devices and Circuit Design
Authors: Scott Madaras
Source: W&M Publish (College of William & Mary) (article, 2021-03-22)
Field: Materials Science — Polymers and Plastics

Insulator To Metal Transition Dynamics Of Vanadium Dioxide Thin Films Vanadium Dioxide (VO2) is a strongly correlated material which has been studied for many decades. VO2 has been proposed for uses in technologies such as optical modulators, IR modulators, optical switches and Mott memory devices. These technologies are taking advantage of VO2’s insulator to metal transition (IMT) and the corresponding changes to the optical and material properties. The insulator to metal transition in VO2 can be accessed by thermal heating, applied electric field, or ultra-fast photo induced processes. Recently, thin films of VO2 grown on Titanium Dioxide doped with Niobium (TiO2:Nb), have shown promise as a possible UV photo detector with high quantum efficiency which utilizes a heterostructure between these two materials. In this work, the dynamics of the IMT on thin films of VO2 is explored. We show that surface plasmons generated in an Au thin film can induce the insulator to metal transition in a thin film of VO2 due to the enhanced electric field as well as help detect the IMT via changes in its resonance condition. Time resolved pump probe studies were also done on thin films of VO2 grown on TiO2 and TiO2:Nb, using UV photon energy of 3.1 eV (400nm wavelength). The fluence threshold of the IMT at 3.1 eV was significantly lower than published values for the 1.55 eV pump fluence. The time response of the IMT shows uncommon reflectivity dynamics in these samples. The response was partially attributed to internal interference of the reflected probe beam from the inhomogeneous layers formed inside the film by different phases of VO2, and can be elucidated by a diffusion model with respect to its optical properties. Finally, the photocurrent generation time constants for the sample with highest quantum efficiency are given and compared to its ultrafast photo induced IMT time constants. Vanadium dioxide ; Metal–insulator transition ; Materials science ; Vanadium ; Thin film ; Transition metal ; Metal ; Condensed matter physics ; Chemical physics ; Metallurgy ; Nanotechnology ; Chemistry ; Physics ; Catalysis Transition Metal Oxide Nanomaterials ; Catalysis and Oxidation Reactions
Authors: Dongying Xu | Zhiyin Xie | Yu Jing | Jianying Liu | Chenghua Xu | Zhiyong Deng | Wanting Zhai | Hao Qi
Source: 复合材料学报 (article, 2021-08-01)
Field: Chemistry — Organic Chemistry

Adsorption mechanism of ofloxacin in water with "core-shell" magnetic adsorbent Mn 0.6 Zn 0.4 Fe 2 O 4 @SiO 2 -CeO 2 capable of oxidation regeneration In order to remove ofloxacin (OFXL), which is difficult to biodegrade in water, and break through the bottleneck of solid-liquid separation and regeneration of adsorbents, Mn0.6Zn0.4Fe2O4 magnetic nanoparticles were modified by SiO2 and CeO2 to prepare Mn0.6Zn0.4Fe2O4@SiO2-CeO2 (MFSC) magnetic nanocompsite adsorbents. The as-prepared MFSC were systematically characterized using X-ray diffraction, infrared spectroscopy, scanning electron microscope, transmission electron microscope, vibration sample magnetometer. The investigation results of three kinetic models (quasi-first-order kinetics, quasi-second-order kinetics, and intraparticle diffusion models), three isotherm models (Langmuir, Freundlich and D-R models) and adsorption thermodynamics show that the adsorption rate is controlled by multiple factors such as intra-particle diffusion and liquid film diffusion; the adsorption process is dominated by physical adsorption, and the chemical adsorption is the rate-controlling step; the adsorption process is spontaneously and exothermic with entropy increase. The characterization results of infrared spectroscopy and X-ray photoelectron spectroscopy indicate that the interaction forces between MFSC and OFLX include π-π conjugation, hydrogen bonding and coordination. After six cycles of adsorption-oxidation regeneration in situ, the equilibrium adsorption capacity of MFSC for OFLX is 27.00 mg·g−1. The research results can provide basic theoretical data on the control technology of nonbiodegradable OFLX. Adsorption ; Chemistry ; Freundlich equation ; X-ray photoelectron spectroscopy ; Infrared spectroscopy ; Analytical Chemistry (journal) ; Scanning electron microscope ; Langmuir ; Chemical engineering ; Endothermic process ; Inorganic chemistry ; Materials science ; Physical chemistry ; Chromatography ; Organic chemistry ; Composite material Nanomaterials for catalytic reactions ; Adsorption and biosorption for pollutant removal ; Iron oxide chemistry and applications