bluuebunny/crossref_metadata_2025_split huggingface dataset:
Non-uniform superlattice magnetic tunnel junctions
Authors: Chakraborti Sabarna , Sharma Abhishek 
Published: January 2023

Abstract
We propose a new class of non-uniform superlattice magnetic tunnel junctions (Nu-SLTJs) with the linear, Gaussian, Lorentzian, and Pöschl–Teller width and height based profiles manifesting a sizable enhancement in the TMR (≈104 − 106%) with a significant suppression in the switching bias (≈9 folds) owing to the physics of broad-band spin filtering. By exploring the negative differential resistance region in the current–voltage characteristics of the various Nu-SLTJs, we predict the Nu-SLTJs offer fastest spin transfer torque switching in the order of a few hundred picoseconds. We self-consistently employ the atomistic non-equilibrium Green’s function formalism coupled with the Landau–Lifshitz–Gilbert–Slonczewski equation to evaluate the device performance of the various Nu-SLTJs. We also present the design of minimal three-barrier Nu-SLTJs having significant TMR (≈104%) and large spin current for the ease of device fabrication. We hope that the class of Nu-SLTJs proposed in this work may lay the bedrock to embark on the exhilarating voyage of exploring various non-uniform superlattices for the next generation of spintronic devices.
Bright, small sizes and hydro-dispersive NIR persistent luminescence nanoparticles modified with Si and amino groups for enhanced bioimaging
Authors: Fu Jing , Lv Qi-Yan , Li Yan-Shuai , Song Xiaojie , Zhu Qi , Ren Xueling , Cui Hui-Fang 
Published: January 2023

Abstract
Near-infrared (NIR) persistent luminescence nanoparticles (PLNPs) with high brightness, small sizes, good hydro-dispersivity, and intrinsic surface-functional groups are desirable in biological applications. In this work, Cr3+-doped zinc gallogermanates Zn1+x
Ga2−2x
Ge
x
O4:Cr (ZGGC) PLNPs were hydrothermally synthesized via 3-aminopropyltriethoxysilane (APTES) as an additive, or APTES and cetyltrimethylammonium bromide (CTAB) as two co-additives. Addition of APTES not only dramatically enhances the 696 nm NIR luminescence intensity, but also obviously decreases the particle size and introduces amino groups. In particular, the x = 0.1 series ZGGC (ZGGC0.1) with the addition of n moles equivalent APTES (ZGGC0.1-nA) had smaller particle sizes than the x = 0.2 counterpart (ZGGC0.2-nA). The NIR afterglow intensities increased with the APTES introduction. The ZGGC0.2-2.5A sample (also named as ZGGC, Si, -NH2) exhibited maximum luminescence intensities both in solid and aqueous states. With APTES, Si atom is doped and –NH2 groups are modified, the trap depth and density become larger, and the afterglow intensities and decay time are significantly enhanced. More notably, co-addition of CTAB (ZGGC0.2-2.5A-C) (also named as ZGGC, Si, −NH2’) further enhances hydro-dispersivity and luminescence intensity, decreases particle sizes, and results in more prominent amino groups. The trap density is drastically higher than that without CTAB (i.e. ZGGC0.2-2.5A). Change of Cr3+ microenvironment in the crystal and more defects introduction contribute to the enhanced brightness. As expected, the ZGGC,Si,-NH2’ PLNPs possess excellent biocompatibility, deep tissue penetration and distinguished bioimaging properties, and rechargeability with orange LED light. The ZGGC,Si,-NH2’ PLNPs should provide to be an excellent nanomaterial for various functionalization and bioimaging applications.
Resistive switching mechanism of MoS2 based atomristor
Authors: Li Xiao-Dong , Wang Bai-Qian , Chen Nian-Ke , Li Xian-Bin 
Published: January 2023

Abstract
The non-volatile resistive switching process of a MoS2 based atomristor with a vertical structure is investigated by first-principles calculations. It is found that the monolayer MoS2 with S vacancy defects (Vs) could maintain an insulation characteristic and a high resistance state (HRS) is also remained. As an electrode metal atom adsorbed on MoS2 monolayer, the semi-conductive filament is formed with the assistance of Vs. Under this condition the atomristor presents a low resistance state (LRS). The ON state current of this semi-filament is increased close to two orders than that of without filament (HRS). The energy barrier for an Au-atom to penetrate the monolayer MoS2 via Vs is as high as 6.991 eV. When it comes to double S vacancy (Vs2), the energy barrier is still amounted to 3.554 eV, which manifests the bridge-like full conductive filaments cannot form in monolayer MoS2 based atomristor. The investigation here promotes the atomistic understanding of the resistive switching properties about the monolayer MoS2 based memristor. The physics behind should also work in atomristors based on other monolayer transitional metal dichalcogenides, like WeSe2 and MoTe2. The investigation here will promote the comprehension of these devices at atomic scale and be a reference for device design or optimization.
Core integrated simulations for the Divertor Tokamak Test facility scenarios towards consistent core-pedestal-SOL modelling
Authors: Casiraghi I , Mantica P , Ambrosino R , Aucone L , Baiocchi B , Balbinot L , Barberis T , Castaldo A , Cavedon M , Frassinetti L , Innocente P , Koechl F , Nowak S , Agostinetti P , Ceccuzzi S , Figini L , Granucci G , Vincenzi P 
Published: January 2023

Abstract
Deuterium plasma discharges of the Divertor Tokamak Test facility (DTT) in different operational scenarios have been predicted by a comprehensive first-principle based integrated modelling activity using state-of-art quasi-linear transport models. The results of this work refer to the updated DTT configuration, which includes a device size optimisation (enlargement to

R
0

=

2.19

m and a = 0.70 m) and upgrades in the heating systems. The focus of this paper is on the core modelling, but special attention was paid to the consistency with the scrape-off layer parameters required to achieve divertor plasma detachment. The compatibility of these physics-based predicted scenarios with the electromagnetic coil system capabilities was then verified. In addition, first estimates of DTT sawteeth and of DTT edge localised modes were achieved.
Resonant printing flexible piezoresistive pressure sensor with spherical microstructures
Authors: Yu Zhiheng , Hu Guohong , Chen Jian , Huang Fengli , Zhao Yun , Feng Jijun 
Published: January 2023

Abstract
Flexible pressure sensors have attracted much attention in academia owing to their wide-ranging applications in wearable electronics, medical electronics and digital health. However, practical engineering applications have been restricted because of limitations in efficiency, manufacturing costs and sensitivity. In this work, we propose an innovative method for high-efficiency printing of microstructures that replaces traditional inverted mold methods. We developed a high-sensitivity flexible piezoresistive pressure (FPP) sensor with a high manufacturing efficiency and low manufacturing cost. The sensor was encapsulated by connecting a polydimethylsiloxane film with microstructures prepared using the sandpaper-molding method, and then integrated with an interdigital electrode and spherical micro-structures fabricated via resonant printing. In this way, the manufacturing process was simplified by breaking it down into two steps. The performance of the sensor was assessed by conducting experiments under different pressure regimes. The results demonstrated ultra-high sensitivity (0.0058–0.024 kPa−1) and a wide pressure detection range (1–100 kPa), spanning the entire range of pressure monitoring typically observed for vital and health signals. The response time of the sensor was less than 72 ms. Furthermore, the performance of the fabricated sensor was highly stable after 1000 bending cycle. The potential applications of the FPP sensor are discussed in area such as the human body and mouse.
Constraining study of Rastall parameter on charged anisotropic compact star model
Authors: Ashraf Asifa , Shahzad M R , Zhang Zhiyue , Güdekli Ertan , Jamal M Farooq 
Published: January 2023

Abstract
The current study discusses the charge anisotropic stellar structures in Rastall theory. For this study, the Karmarkar condition is considered to develop the embedded solutions of compact stars. To complete this analysis, the spherically symmetric spacetime is taken, and solve the resulting Rastall field equations by constraining different values of the Rastall parameter, i.e., ξ = −0.03, ξ = −0.06, and ξ = −0.09 into account. Further, we choose a well-known interesting form of g

rr
metric component as

e

λ
(
r
)

=
1
+

cr

2

1
+

ar

2

n

1
+

br

2

2

. We explore the properties of compact star models like Vela X-1, under the effect of different positive values of n, i.e., 1.8 ≤ n < 7, with n ≠ 2, 4, 6. It is noted that some results are not satisfied for n ≥ 6.6. We show that the parameters n (appearing due to the g

rr
) and Rastall parameter ξ play an important role in determining the thermodynamical behavior and stability of our model. The detailed analysis of the physical parameters like pressure components, energy density, charge density, and stability features including adiabatic index has been provided with graphical and numerical investigations. It is important to mention here that our obtained solutions are physically viable and well-stable.
A coupled quantum-molecular mechanics approach for performance analysis of defective Silicon based photovoltaic solar cells
Authors: SDVSS Varma Siruvuri , Mangipudi K R , Budarapu P R 
Published: January 2023

Abstract
Although, molecular mechanics (MM) based approaches are capable of simulating the dynamic charge motion of atoms over time scales up to femto-seconds, the accuracy is an issue. As a result, quantum-mechanics (QM) based approaches are a choice to predict accurate dynamic motion of atomic charges. However, computational cost of QM simulations is significantly higher than that of MM simulations. In this study, a computationally efficient coupled QM/MM model is developed by combining the QM and MM approaches, enabling simulation of larger domains with accurate estimates. The proposed methodology is implemented with the help of QMMM package available in large-scale atomic/molecular massively parallel simulator (LAMMPS), to investigate the dynamic charge motion in the presence of cracks in Silicon. A Silicon domain of dimensions 48.87 Å × 48.87 Å × 5.43 Å is considered in the simulations. Furthermore, a small domain around the crack tip, with dimensions 4 Å × 4 Å is identified for carrying out QM analysis and denoted as embedded region (ER). Simulations are performed considering four different cases: (i) pristine Silicon, (ii) Silicon with an initial edge crack, (iii) pristine Silicon with Graphene deposition, and (iv) Graphene deposited Silicon containing an initial edge crack. In the coupled model, first, for the given load step, considering the minimum energy criteria molecular dynamics simulations are performed over the entire domain. This is followed by QM simulations over an identified ER based on first principle studies using the plane wave density functional theory. The latest atom positions from the QM simulations are updated in the MM domain before proceeding to the next load step. The electrical performance of Silicon solar cells is studied by estimating the effective Bader charge and total electric power. The effective Bader charge for atoms in QM domain is observed to be significantly higher indicating charge accumulation around the crack tip. This is further evidenced through the total electric power estimations, where pristine Silicon with Graphene deposition is observed to possess the highest power followed by cases iv, ii and i.
Problem on piecewise Caputo-Fabrizio fractional delay differential equation under anti-periodic boundary conditions
Authors: Filali D , Ali Arshad , Ali Zeeshan , Akram M , Dilshad M , Agarwal Praveen 
Published: January 2023

Abstract
This manuscript considers a class of piecewise differential equations (DEs) modeled with the Caputo-Fabrizio differential operator. The proposed problem involves a proportional delay term and is equipped with anti-periodic boundary conditions. The piecewise derivative can be applied to model many complex nature real-world problems that show a multi-step behavior. The existence theory and Hyer-Ulam (HU) stability results are studied for the proposed problem via fixed point techniques such as Banach contraction theorem, Schauder’s fixed point theorem and Arzelá Ascoli theorem. A numerical problem is presented as an example to see the validity and effectiveness of the applied concept.
Modelling light wave propagation and interaction and dynamical regimes analysis using the Lyapunov exponents method in ring fibre cavities
Authors: Razukov V A , Melnikov L A , Kuptsov P V , Gochelashvili K S 
Published: January 2023

Abstract
The ‘Cabaret’ finite differences method allows the performance of fast and conclusive modelling of the microcavity temporal dynamics with group velocity dispersion, cross- and self- phase modulation included. The proposed scheme and model allow us to study the dynamics of a cavity with two counter-propagating pulses, second order dispersion, modulation instability, Rayleigh scattering and other effects along the cavity roundtrips number up to 106…7. The possibility of Lyapunov exponents mapping for the Raman and SBS fibre lasers and cavities is discussed.
The influence of time varying magnetic fields on the determinations of Newton’s constant at the Bureau International des Poids et Mesures
Authors: Speake Clive C , Bryant John L , Davis Richard S , Quinn Terry J 
Published: January 2023

Abstract
The values of Newton’s constant of gravitation, G, reported by determinations at the International Bureau of Weights and Measures (BIPM) in Quinn et al (2001 Phys. Rev. Lett.
87 111101/1–111101/4) and in Quinn et al (2013 Phil. Trans. R. Soc. A
372 2–28) are some 200 parts per million (ppm) larger than the value of

6.67430
×

10

−
11

m3 kg−1 s−2 which was recommended by CODATA in Tiesinga et al (2018 J. Phys. Chem. Ref. Data
50 033105). The CODATA value has an assigned uncertainty of 22 ppm and the reported uncertainties in the BIPM values were 41 ppm and 25 ppm, respectively. The discrepancy therefore amounts to about seven times the combined uncertainty of the latest BIPM and CODATA values. We examine experimentally the hypothesis that the difference is due to a bias produced by stray alternating (AC) magnetic fields in the vicinity of the experiment. Whilst the BIPM torsion balance was located at the University of Birmingham a coil, having a similar scale to the balance, was used to generate AC magnetic fields of magnitude approximately 1 μT which in turn produced torques of magnitude approximately 0.2 % of the gravity torque. The magnitudes of these torques were compared with simple analytical models and finite element analyses. Measurements in the laboratory in Birmingham and, more recently, at BIPM give a very conservative upper limit on the rms magnitude of ambient AC magnetic fields of 100 nT. As the torque was demonstrated to vary with the square of the ambient field, these observations and our analyses suggest an upper limit to the possible bias in the BIPM determinations of the order of 20 ppm. It is therefore unlikely that torques due to ambient magnetic fields could have significantly biased values of G determined at BIPM.
Influence of pulsed TIG welding process parameters on the mechanical characteristics of AA5083 with AA6082 weldments
Authors: A Ramarajan , Jayakumar K 
Published: January 2023

Abstract
Aluminium alloys have been widely accepted in manufacturing lightweight materials with high strength. Therefore, welding aluminium alloys is essential in industrial applications to attain complex shapes. In the present work, AA5083 and AA6082 dissimilar alloys were welded using pulsed tungsten inert gas (PTIG) welding since PTIG reduces welding defects more than TIG welding. But to get better mechanical strength on the weld joints, PTIG welding process parameters must be optimized. During PTIG welding, peak current, pulse frequency, and welding speed were chosen as the input parameters, and ultimate tensile strength (UTS) and microhardness were measured as output responses in the current investigation. The UTS of the welded AA5083-AA6082 alloys was predicted using an empirical relationship. For the design of experimental trials, a three-variable, five-stage central composite design is adopted. The findings indicate that the welding speed impacts tensile strength the most, followed by the peak current and the pulse frequency has the least impact. Therefore, the peak current of 197 A, pulse frequency of 4.9 Hz, and welding speed of 181 mm min−1 was identified as the optimal welding parameters to weld AA5083 and AA6082 alloys with high UTS values. The hardness analysis on the optimized welded samples showed that the lowest hardness values of 40 to 50 Hv0.5 and the highest value of 90 to 100 Hv0.5 were observed on the HAZ of the AA6082 side of the weldment.
A Fourier-transformed feature engineering design for predicting ternary perovskite properties by coupling a two-dimensional convolutional neural network with a support vector machine (Conv2D-SVM)
Authors: Chenebuah Ericsson Tetteh , Nganbe Michel , Tchagang Alain Beaudelaire 
Published: January 2023

Abstract
In computational material sciences, Machine Learning (ML) techniques are now competitive alternatives that can be used in determining target properties conventionally resolved by ab initio quantum mechanical simulations or experimental synthesization. The successes realized with ML-based techniques often rely on the quality of the design architecture, in addition to the descriptors used in representing a chemical compound with good target mapping property. With the perovskite crystal structure at the forefront of modern energy materials discovery, accurately estimating related target properties is even of high importance due to the role such properties may have in defining the functionalization. As a result, the present study proposes a new feature engineering approach that takes advantage of both the direct ionic features and the periodic Fourier transformed reciprocal features of a three-dimensional perovskite polyhedral. The study is conducted on about 27,000 ABX3 perovskite structures with the stability energy, the formation energy, and the energy bandgap as targets. For accurate modeling, a feature-extracting two-dimensional convolutional neural network (Conv2D) is coupled with a prediction-enhancing Support Vector Machine (SVM) to form a hybridized Conv2D-SVM architecture. A comparison with previous benchmark evaluations reveals appreciable improvements in modeling accuracy for all target properties, particularly for the energy bandgap, for which the feature extraction approach yields 0.105 eV MAE, 0.301 eV RMSE, and 93.48% R2. Besides, the proposed design is further demonstrated to out-perform other similar periodic feature engineering approaches in the Coulomb matrix, Ewald-sum matrix, and Sine matrix, all in their absolute eigenvalue forms. All preprocessed data, source codes, and relevant sample calculations are openly available at: github.com/chenebuah/high_dim_descriptor.
First principles study of Ti-Zr-Ta alloy phase stability and elastic properties
Authors: Ruobing Zhang , Lin Ai 
Published: January 2023

AbstractThe effects of Ta and Zr content on the stability, elastic properties and electronic structure of Ti-Zr-Ta alloy phase were studied by first principles calculation method based on density functional theory. Moreover, Ti-Zr-Ta alloy was fabricated by spark plasma sintering (SPS) using spherical Ti powder,Ta powder, and Ti-Zr-Ta alloy powder produced by the plasma rotation electrode process (PREP). Afterward, the effects of sintering temperature, Zr and Ta content on the microstructure and mechanical properties of the alloy samples were investigated. The results showed that sintering temperature, Ta and Zr content were the key factors which affected the densification. When the sintering temperature was raised, the relative density and mechanical properties of Ti-Zr-Ta alloy were significantly increased. The first- principles calculation also indicated that Ti-1Zr-Ta possesses the lowest Young’s modulus and the best ductility, showing great potential of biomedical applications which agrees with the results of experimental results of alloy preparation.
Water demands of permitted and unpermitted cannabis cultivation in Northern California
Authors: Dillis Christopher , Butsic Van , Georgakakos Phillip , Portugal Elijah , Grantham Theodore E 
Published: January 2023

Abstract
Illicit water use for irrigated agriculture can have substantial impacts on the environment and complicates water management decision-making. Water demand for illicit cannabis farming in California has long been considered a threat to watershed health, yet an accounting of cannabis irrigation has remained elusive, thereby impeding effective water policy for the state’s nascent legal cannabis industry. Using data obtained from both permitted and unpermitted cultivation operations, the current study applies novel water-use models to cannabis farms in Northern California to estimate their cumulative and relative water footprints. Our results indicated substantial variation in total water extraction volumes for cannabis farming between watersheds and that most cannabis water use was concentrated in a subset of watersheds, rather than evenly spread across the landscape. Water extraction volumes for unpermitted cannabis were consistently greater than permitted cannabis in the dry season, when streams are most vulnerable to impacts from water diversions. Results from scenario modeling exercises indicated that if all existing unpermitted farms were to become permitted and comply with regulations that prohibit surface water diversions in the dry season, nearly one third (34 of 115) of the study watersheds would experience a 50% reduction in dry season water extraction. In comparison, modest expansion of off-stream storage by all cannabis farms could reduce dry season extraction by 50% or greater in more than three quarters (96 of 115) of study watersheds. Combining diversion limits with enhanced storage could achieve dry season extraction reductions of 50% or greater in 100 of 115 watersheds. Our findings suggest that efforts to address the environmental impacts of unpermitted cultivation should focus on watersheds with greatest water demands and that programs that support expansion of off-stream storage can be helpful for reducing pressures on the environment and facilitating the transition of unpermitted farms to the regulated market.