jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Yucen Han | Apala Majumdar
Source: Journal of Nonlinear Science (article, 2023-01-05)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Multistability for a Reduced Nematic Liquid Crystal Model in the Exterior of 2D Polygons Abstract We study nematic equilibria in an unbounded domain, with a two-dimensional regular polygonal hole with K edges, in a reduced Landau–de Gennes framework. This complements our previous work on the “interior problem” for nematic equilibria confined inside regular polygons (SIAM Journal on Applied Mathematics, 80(4):1678-1703, 2020). The two essential dimensionless model parameters are $$\lambda $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>λ</mml:mi> </mml:math> -the ratio of the edge length of polygon hole to the nematic correlation length, and an additional degree of freedom, $$\gamma ^*$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>γ</mml:mi> <mml:mo>∗</mml:mo> </mml:msup> </mml:math> -the nematic director at infinity. In the $$\lambda \rightarrow 0$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>λ</mml:mi> <mml:mo>→</mml:mo> <mml:mn>0</mml:mn> </mml:mrow> </mml:math> limit, the limiting profile has two interior point defects outside a generic polygon hole, except for a triangle and a square. For a square hole, the limiting profile has either no interior defects or two line defects depending on $$\gamma ^*$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>γ</mml:mi> <mml:mo>∗</mml:mo> </mml:msup> </mml:math> , and for a triangular hole, there is a unique interior point defect outside the hole. In the $$\lambda \rightarrow \infty $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>λ</mml:mi> <mml:mo>→</mml:mo> <mml:mi>∞</mml:mi> </mml:mrow> </mml:math> limit, there are at least $$\left( {\begin{array}{c}K\\ 2\end{array}}\right) $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mfenced> <mml:mrow> <mml:mtable> <mml:mtr> <mml:mtd> <mml:mi>K</mml:mi> </mml:mtd> </mml:mtr> <mml:mtr> <mml:mtd> <mml:mrow> <mml:mrow/> <mml:mn>2</mml:mn> </mml:mrow> </mml:mtd> </mml:mtr> </mml:mtable> </mml:mrow> </mml:mfenced> </mml:math> stable states and the multistability is enhanced by $$\gamma ^*$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>γ</mml:mi> <mml:mo>∗</mml:mo> </mml:msup> </mml:math> , compared to the interior problem. Our work offers new insights into how to tune the existence, location, and dimensionality of defects. Polygon (computer graphics) ; Algorithm ; Dimensionless quantity ; Geometry ; Liquid crystal ; Physics ; Mathematics ; Computer science ; Condensed matter physics ; Thermodynamics Liquid Crystal Research Advancements ; Nonlinear Dynamics and Pattern Formation ; Advanced Materials and Mechanics
Authors: Haochen Feng | Ziwen Cheng | D.W. Long | Tingting Yang | Zhibin Lu | Qi‐Chang He
Source: Lubricants (article, 2023-10-30)
Field: Materials Science — Materials Chemistry

How Do Substrates Affect the Friction on Graphene at the Nanoscale? Substrates supporting two-dimensional materials are omnipresent in micro/nano electromechanical systems. Moreover, substrates are indispensable to all nanotribological experimental systems. However, substrates have rarely been taken into account in first-principles simulations of nanotribological systems. In this work, we investigate the effects of substrates on nanofriction by carrying out first-principles simulations of two systems: (a) one graphene monolayer sliding on another one supported by a metal substrate, denoted as the Gr-Gr/Metal system; and (b) a diatomic tip sliding on a graphene monolayer supported by a metal substrate, named the Tip-Gr/Metal system. Each substrate is made of triatomic layers constituting the minimum period and obtained by cutting a metal through its (111) surface. By varying metal substrates and analyzing the results of the first-principles simulations, it follows that (i) the fluctuation in the sliding energy barriers of the two systems can be modified by changing substrates; (ii) the adsorption type and the pressure affect friction; (iii) the presence of a substrate varies the interfacial binding strength; and (iv) the modulation of friction by substrates lies in altering the interface electron density. These results provide an answer to the important question of how substrates affect the friction on graphene at the nanoscale. Graphene ; Monolayer ; Materials science ; Substrate (aquarium) ; Nanoscopic scale ; Nanotechnology ; Metal ; Nanoelectronics ; Chemical physics ; Composite material ; Chemistry ; Metallurgy Graphene research and applications ; Force Microscopy Techniques and Applications ; Molecular Junctions and Nanostructures
Authors: Mengke Qiao | Xiangcheng Li | Zhangqi Liao | Pingan Chen | Yingli Zhu
Source: physica status solidi (RRL) - Rapid Research Letters (article, 2023-01-12)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Multioctagonal Ring Metamaterial with Broadband Microwave Absorption at Elevated Temperature Excellent thermostable performance is the basis for the further development of microwave absorbing materials in the field of military stealth. Herein, a high‐temperature metamaterial absorber (HMA) with high impedance patterns (multi‐octagonal‐rings), two quartz (SiO 2 ) layers, and a metallic ground film is designed and simulated. The optimal structural parameters are obtained by optimizing the circuit parameters and the size of HMA. The interaction of electric and magnetic resonance in multioctagonal rings results in a wide absorption bandwidth and excellent absorption performance. The experimental results show that the structure has good impedance matching performance, and the effective absorption bandwidth (−10 dB) (EAB) of the structure can reach 10.6 GHz from room temperature to 700 °C under the combined effect of resonance loss and ohmic loss. Materials science ; Microwave ; Impedance matching ; Metamaterial ; Broadband ; Electrical impedance ; Absorption (acoustics) ; Bandwidth (computing) ; Optoelectronics ; Metamaterial absorber ; Resonance (particle physics) ; Optics ; Composite material ; Tunable metamaterials ; Telecommunications ; Electrical engineering ; Atomic physics ; Computer science Metamaterials and Metasurfaces Applications ; Advanced Antenna and Metasurface Technologies ; Electromagnetic wave absorption materials
Authors: Šimon Gans | Ján Molnár | Dobroslav Kováč | Irena Kováčová | Branislav Fecko | Matej Bereš | Patrik Jacko | Jozef Dziak | Tibor Vince
Source: Sensors (article, 2023-10-11)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Driving Signal and Geometry Analysis of a Magnetoelastic Bending Mode Pressductor Type Sensor The paper deals with a brief overview of magnetoelastic sensors and magnetoelastic sensors used in general for sensing bending forces, either directly or sensing bent structures, and defines the current state of the art. Bulk magnetoelastic force sensors are usually manufactured from transformer sheets or amorphous alloys. In praxis, usually, a compressive force is sensed by bulk magnetoelastic sensors; however, in this paper, the sensor is used for the measurement of bending forces, one reason being that the effect of such forces is easily experimentally tested, whereas compressive forces acting on a single sheet make buckling prevention a challenge. The measurement of the material characteristics that served as inputs into a FEM simulation model of the sensor is presented and described. The used material was considered to be mechanically and magnetically isotropic and magnetically nonlinear, even though the real sheet showed anisotropic behavior to some degree. A sinusoidal magnetizing current waveform was used in the experimental part of this paper, which was created by a current source. The effects of various frequencies, amplitudes, and sensor geometries were tested. The experimental part of this paper studies the sensors' RMS voltage changes to different loadings that bend the sheet out of its plane. The output voltage was the induced voltage in the secondary coil and was further analyzed to compute the linearity and sensitivity of the sensor at the specific current characteristic. It was found that for the given material, the most favorable operating conditions are obtained with higher frequency signals and higher excitation current amplitudes. The linearity of the sensor can be improved by placing the holes of the windings at different angles than 90° and by placing them further apart along the sheet's length. The current source was created by a simple op-amp voltage-to-current source controlled by a signal generator, which created a stable waveform. It was found that transformer sheet bending sensors with the dimensions described in this paper are suitable for the measurement of small forces in the range of up to 2 N for the shorter sensors and approximately 0.2 N for the longer sensors. Waveform ; Linearity ; Materials science ; Acoustics ; Isotropy ; Voltage ; Electromagnetic coil ; Anisotropy ; Bending ; SIGNAL (programming language) ; Structural engineering ; Electrical engineering ; Engineering ; Optics ; Physics ; Composite material ; Computer science Magnetic Properties and Applications ; Magneto-Optical Properties and Applications ; Acoustic Wave Resonator Technologies
Authors: Peder E.Z. Larson | Jenna Bernard | James A. Bankson | Nikolaj Bøgh | Robert Bok | Albert P. Chen | Charles H. Cunningham | Jeremy W. Gordon | Jan‐Bernd Hövener | Christoffer Laustsen | Dirk Mayer | Mary A. McLean | Franz Schilling | James Slater | Jean‐Luc Vanderheyden | Cornelius von Morze | Daniel B. Vigneron | Duan Xu
Source: PubMed (preprint, 2023-11-22)
Field: Chemistry — Spectroscopy

Current Methods for Hyperpolarized [1-<sup>13</sup>C]pyruvate MRI Human Studies. MRI with hyperpolarized (HP) <sup>13</sup>C agents, also known as HP <sup>13</sup>C MRI, can measure processes such as localized metabolism that is altered in numerous cancers, liver, heart, kidney diseases, and more. It has been translated into human studies during the past 10 years, with recent rapid growth in studies largely based on increasing availability of hyperpolarized agent preparation methods suitable for use in humans. This paper aims to capture the current successful practices for HP MRI human studies with [1-<sup>13</sup>C]pyruvate - by far the most commonly used agent, which sits at a key metabolic junction in glycolysis. The paper is divided into four major topic areas: (1) HP <sup>13</sup>C-pyruvate preparation, (2) MRI system setup and calibrations, (3) data acquisition and image reconstruction, and (4) data analysis and quantification. In each area, we identified the key components for a successful study, summarized both published studies and current practices, and discuss evidence gaps, strengths, and limitations. This paper is the output of the "HP <sup>13</sup>C MRI Consensus Group" as well as the ISMRM Hyperpolarized Media MR and Hyperpolarized Methods & Equipment study groups. It further aims to provide a comprehensive reference for future consensus building as the field continues to advance human studies with this metabolic imaging modality. Medicine ; Computer science ; Neuroscience ; Medical physics ; Biology Advanced NMR Techniques and Applications ; Advanced MRI Techniques and Applications ; Atomic and Subatomic Physics Research
Authors: Grzegorz Chojnowski
Source: Acta Crystallographica Section D Structural Biology (article, 2023-05-17)
Field: Materials Science — Materials Chemistry

Sequence-assignment validation in protein crystal structure models with <i>checkMySequence</i> Sequence-register shifts remain one of the most elusive errors in experimental macromolecular models. They may affect model interpretation and propagate to newly built models from older structures. In a recent publication, it was shown that register shifts in cryo-EM models of proteins can be detected using a systematic reassignment of short model fragments to the target sequence. Here, it is shown that the same approach can be used to detect register shifts in crystal structure models using standard, model-bias-corrected electron-density maps (2mF<sub>o</sub> - DF<sub>c</sub>). Five register-shift errors in models deposited in the PDB detected using this method are described in detail. Sequence (biology) ; Computational biology ; Computer science ; Crystallography ; Chemistry ; Biology ; Biochemistry Enzyme Structure and Function ; Protein Structure and Dynamics ; Genomics and Phylogenetic Studies
Authors: Xuewen Yan | Chen Cheng | Juan Hu | Y. Bai | Wenwen Zhang
Source: IEICE Electronics Express (article, 2023-10-24)
Field: Materials Science — Materials Chemistry

Design and implementation of a novel high-frequency current transformer for partial discharge measurements This study focuses on the improvement of the performance of high-frequency current transformer (HFCT) for Partial Discharge Measurement and thus reveals a new design method of HFCT. An annular nickel-zinc ferrite is used as the magnetic core of the HFCT, and the parameters such as the number of winding turns and the diameter of the enameled wire are optimized. To test the HFCT, an experimental test platform is built according to the technical specifications of high-frequency partial discharge charged detection equipment. The test contents of the HFCT include transmission impedance, sensitivity, anti-interference characteristics, etc. The test results show that the new HFCT has a good response performance from 1MHz to 25MHz, the maximum transmission impedance value can reach 16.4mV/mA, the apparent charge of 5pC can be measured and signal-to-noise ratio is greater than 2:1. In addition, the designed HFCT also has good anti-interference and stability. With the self-designed low-power portable high-voltage cable insulation tester (mainly including signal conditioning circuit and data acquisition circuit), in the high-voltage laboratory, built a simulated discharge experimental circuit on the plate-pin, ball-ball two discharge models for high-voltage testing, the use of the developed HFCT to detect the partial discharge of the insulating polyethylene medium. The test results show that the HFCT can detect the partial discharge pulse signals before breakdown, with accurate data and reliable performance. Partial discharge ; Current transformer ; Materials science ; Waveform ; Acoustics ; Transformer ; Voltage ; Electrical impedance ; Electromagnetic interference ; Electronic engineering ; Electrical engineering ; Engineering ; Physics High voltage insulation and dielectric phenomena ; Magnetic Field Sensors Techniques ; Magneto-Optical Properties and Applications
Authors: Donghyun Hong | Yaewon Kim | Chandrasekhar Mushti | Noriaki Minami | Jing Wu | Murali Cherukuri | Rolf E. Swenson | Daniel B. Vigneron | Sabrina M. Ronen
Source: Neuro-Oncology Advances (article, 2023-01-01)
Field: Chemistry — Spectroscopy

Monitoring response to a clinically relevant IDH inhibitor in glioma—Hyperpolarized 13C magnetic resonance spectroscopy approaches Our findings point to the clinical potential of HP αKG, which recently received FDA investigational new drug approval for research, for noninvasive localized imaging of IDHmut status. Glioma ; Nuclear magnetic resonance ; Magnetic resonance imaging ; Nuclear magnetic resonance spectroscopy ; Medicine ; Cancer research ; Physics ; Radiology Advanced NMR Techniques and Applications ; Enzyme Structure and Function ; Mechanisms of cancer metastasis
Authors: Sergey G. Abaimov | Iskander S. Akmanov | Stepan Vladimirovitch Lomov
Source: Applied Physics Letters (article, 2023-07-24)
Field: Materials Science — Materials Chemistry

Overcoming the singularity of 1D embedment enhances computational efficiency of CNT nanocomposite thermal analysis multifold In the digital era, novel smart materials require digital design with the more increasing demand on computational performance, the smaller scale we approach. Nanocomposites present an ultimate challenge, where the morphology of filler particles and their interactions with polymer have to be addressed. For carbon nanotube (CNT)-like particles, computational efficiency would increase multifold if we were able to replace these complex interactions with an equivalent 1D geometry. Unfortunately, for thermal analysis, it results in a singularity of infinite temperature. In this study, relying on undocumented yet possibilities in Abaqus software, we develop a technique to overcome the singularity and apply it to an aligned-CNT nanocomposite. Digital twin is populated with 3D particle morphology obtained by electron tomography, and numerical simulations demonstrate close reproducibility of experimentally measured values for homogenized thermal conductivity. Carbon nanotube ; Nanocomposite ; Materials science ; Singularity ; Thermal conductivity ; Composite material ; Thermal ; Nanotechnology ; Embedment ; Physics ; Geometry ; Mathematics ; Thermodynamics Thermal properties of materials ; Composite Material Mechanics ; Carbon Nanotubes in Composites
Authors: Prodromos Minaoglou | Konstantinos G. Kakoulis | Athanasios Manavis | Panagiotis Kyratsis
Source: International Journal of Modern Manufacturing Technologies (article, 2023-12-20)
Field: Materials Science — Polymers and Plastics

COMPUTATIONAL WEARABLES DESIGN: SHOE SOLE MODELING AND PROTOTYPING Computational wearables design is based on the integration of algorithms into the design process. The use of computational design tools offers a series of advantages in the wearable product design modelling because a complete family of products can be produced with a limited effort from the designer, while at the same time geometries with high complexity can be dealt with a manageable way. The present paper aims to create the appropriate code for modelling shoe soles. The use of a visual programming language leads to a better understanding of the produced code and aims in controlling and optimising the output models. Following the proposed methodology, 3D scanning technologies and plantar pressure diagrams are used for introducing the sole customised geometry, and then the proposed algorithm creates a variety of alternatives of the final shoe sole geometry. As a result, both the customisation and the high number of alternative designs lead to increased creativity and customer satisfaction. Due to the complexity of the geometry produced, 3D printing technologies are incorporated for the prototype implementation. Computer science ; Wearable computer ; Process (computing) ; Product design ; Variety (cybernetics) ; Engineering design process ; Design process ; Product (mathematics) ; 3D printing ; Code (set theory) ; Engineering drawing ; Flexibility (engineering) ; Rapid prototyping ; Virtual prototyping ; Embedded system ; Simulation ; Engineering ; Programming language ; Work in process ; Artificial intelligence ; Mechanical engineering ; Mathematics ; Set (abstract data type) Textile materials and evaluations ; 3D Shape Modeling and Analysis ; Transport Systems and Technology
Authors: Rachid Ghritli | Yasunori Okano | Yuko Inatomi | S. Dost
Source: JOURNAL OF CHEMICAL ENGINEERING OF JAPAN (article, 2023-06-26)
Field: Materials Science — Materials Chemistry

A Numerical Study for the Growth of InGaSb Crystals with a Flatter Interface by Vertical Gradient Freezing under Normal Gravity and Utilizing Bayesian Optimization Growth of InGaSb crystals with a flatter growth interface by Vertical Gradient Freezing (VFG) under normal gravity was numerically investigated. The growth of high-quality crystals is difficult due to the adverse effect of natural convection under the effect of Earth’s gravity. The natural convection developing in the melt leads to an undesirable non-flat growth interface and thus affects the quality of grown crystals. In order to obtain a flatter growth interface and better compositional uniformity in the melt, the applications of crucible rotation and external magnetic field are considered. We carried out a numerical study to optimize growth parameters for these purposes. We also considered the utilization of Bayesian optimization to have a fast search for most favorable control parameters. Such an optimization has led to a significant reduction in the growth interface deflection and a flatter growth interface was maintained during the entire growth process. Strength of natural convection in the melt was minimized and melt solute uniformity was improved. The growth rate was also increased without compromising crystal quality. Simulation results showed that the use of a numerical simulation together with Bayesian optimization is an effective way to provide a better control for the growth parameters involved. Convection ; Mechanics ; Natural convection ; Materials science ; Temperature gradient ; Crystal growth ; Zero gravity ; Computer simulation ; Chemistry ; Thermodynamics ; Physics ; Meteorology Solidification and crystal growth phenomena ; Advanced Thermodynamics and Statistical Mechanics ; Heat Transfer and Optimization
Authors: Yuan Li | Han Li | Wenbo Zhang | Chen Wang | Guanjun Zhang
Source: IEEE Transactions on Industry Applications (article, 2023-01-05)
Field: Chemistry — Analytical Chemistry

Gaussian Process Regression for Quantitative Degree of Polymerization Analysis of Oil-Paper Insulation by EPO-NIRS: A Solution to Field Moisture In recent years, the near infrared (NIR) spectroscopy has been used in prediction of the degree of polymerization (DP) of oil-paper insulation, but the practices show that the field moisture has a significant influence on the acquired spectra. In this paper, an EPO-GPR model is proposed to eliminate the interference of external moisture and hence to improve the prediction performance of DP of insulating paper in the laboratory as well as on-site experiments. In this model, external parameter orthogonalization (EPO) extracts the differences between the insulating paper samples with varying moisture contents and builds a projection matrix orthogonal to the moisture spectral information; the Gaussian process regression (GPR) with optimized Matérn kernel is employed to mapping the correlation between the spectra and DP of insulating paper. Compared with classical PLS and BPNN models, the EPO-GPR model achieves high prediction accuracy in the laboratory testing (RMSE of 71) and field experiments (RMSE of ∼ 60). The proposed EPO-GPR model can provide a solution to field moisture when using the NIR spectroscopy technique to on-site assess the aging condition of insulating papers. Moisture ; Ground-penetrating radar ; Kriging ; Water content ; Near-infrared spectroscopy ; Oil field ; Biological system ; Environmental science ; Kernel (algebra) ; Regression analysis ; Soil science ; Materials science ; Mathematics ; Computer science ; Statistics ; Engineering ; Radar ; Composite material ; Petroleum engineering ; Physics ; Optics Spectroscopy and Chemometric Analyses ; Water Quality Monitoring and Analysis ; Cultural Heritage Materials Analysis