bluuebunny/crossref_metadata_2025 huggingface dataset:
Implementation of a level-set-based volume penalization method for solving fluid flows around bluff bodies
Authors: Kumar Prashant , Kumar Vivek , Chen Di , Hasegawa Yosuke
Published: January 2024

A volume penalization-based immersed boundary technique is developed and thoroughly validated for fluid flow problems, specifically flow over bluff bodies. The proposed algorithm has been implemented in an open source field operation and manipulation (OpenFOAM), a computational fluid dynamics solver. The immersed boundary method offers the advantage of inserting a complex solid object inside a Cartesian grid system, and therefore, the governing equations can be applied to such a simpler grid arrangement. For capturing the fluid–solid interface more accurately, the grid is refined near the solid surface using topoSetDict and refineMeshDict utilities in OpenFOAM. In order to avoid any numerical oscillation and to compute the gradients accurately near the interface, the present volume penalization method (VPM) is integrated with a signed distance function, which is also referred to as a level-set function. Benchmark problems, such as flows around a cylinder and a sphere, are considered and thoroughly validated with the results available in the literature. For the flow over a stationary cylinder, the Reynolds number is varied so that it covers from a steady two-dimensional flow to an unsteady three-dimensional flow. The capability of the present solver has been further verified by considering the flow past a vibrating cylinder in the cross-stream direction. In addition, a flow over a sphere, which is inherently three-dimensional due to its geometrical shape, is validated in both steady and unsteady regimes. The results obtained by the present VPM show good agreement with those obtained by a body-fitted grid using the same numerical scheme as that of the VPM, and also with those reported in the literature. The present results indicate that the VPM-based immersed boundary technique can be widely applicable to scientific and engineering problems involving flow past stationary and moving bluff bodies of arbitrary geometry.
Controlling grain growth to achieve improved magnetic properties of NdCeFeB magnets via grain boundary diffusion
Authors: Huang Y. L. , Feng Q. , Li W. , Yang C. , Chai W. X. , Luo J. M. , Pang Z. S. , Yu X. , Zhao L. Z. , Hou Y. H.
Published: January 2024

The abnormal growth of grains near the surface of NdCeFeB magnets reduces the number of grain boundaries, and meanwhile, the formation of REFe2 phase also hinders the diffusion of rare earth elements, both of which limit the enhancement of magnetic properties. This poses a certain challenge for the preparation of high Ce content NdCeFeB magnets. In this work, it is found that the TbPrNdAl diffusion source can suppress the mutual diffusion between Ce in the main phase and rare earth elements in the diffusion source, thereby restraining the abnormal growth of grains and inhibiting the formation of REFe2 phase. Eventually, a more uniform core-shell structure and thin and continuous RE-rich phase are formed. The coercivity of 1389 kA/m and magnetic energy product of 289 kJ/m3 can be obtained without reducing the remanence, which are 612 kA/m and 30 kJ/m3 higher than those of the initial magnet, respectively. This diffusion source can greatly promote the development of NdCeFeB magnets with high Ce content.
Optimization of effective electron mass in strained silicon nanosheets
Authors: Horii H. , Ueda A. , Hayashi Y.
Published: January 2024

This work investigated the effective mass of electrons in silicon nanosheets confined in the [001] and [1̄10] directions and having thicknesses of several nanometers with uniaxial tensile stress in the [110] direction, using density functional theory. The results show that the confinement along [1̄10] substantially reduces the effective mass in the [110] direction even in the absence of stress—a phenomenon not observed under [100] confinement. Our theoretical analysis reveals that confinement in the [110] direction acts as an effective shear strain. Furthermore, our study identifies an optimal stress that minimizes the effective mass in the transport direction, m110, thereby improving the nanosheet’s transport properties.
On the insignificance of dislocations in reverse bias degradation of lateral GaN-on-Si devices
Authors: Stabentheiner M. , Diehle P. , Hübner S. , Lejoyeux M. , Altmann F. , Neumann R. , Taylor A. A. , Pogany D. , Ostermaier C.
Published: January 2024

The role of threading dislocations in the intrinsic degradation of lateral GaN devices during high reverse bias stress tests (RBSTs) is largely unknown. We now present the results on lateral p-GaN/AlGaN/2DEG heterojunctions with a width of 200 μm in GaN-on-Si. A time-dependent permanent degradation of the heterojunction under high reverse bias and elevated temperatures can be observed, ultimately leading to a hard breakdown and device destruction. By using an integrated series p-GaN resistor, the device is protected from destruction and, consequently, the influence of dislocations on the degradation mechanism could be studied. Localization by emission microscopy could show that the transient current increase during a RBST is the result of the creation of a limited amount of highly localized leakage paths along the whole device width. We could establish a 1:1 correlation of leakage sites with a structural material degradation within the AlGaN barrier for nine individual positions on two different devices by planar transmission electron microscopy analysis. To unambiguously show whether dislocations in GaN-on-Si even should be considered a potential trigger for the RBST degradation in lateral heterojunctions, a combined planar and cross-sectional lamella approach was used for the first time for larger devices. This enabled the visualization of the three-dimensional propagation path of the dislocations close to the degradation sites. It was found that there is no statistically significant link between the material degradation and pre-existing dislocations. Our findings offer new insights into the GaN-on-Si material system, upon which upcoming power technologies are built upon.
Kinetic simulations comparing quasi-parallel and quasi-perpendicular piston-driven collisionless shock dynamics in magnetized laboratory plasmas
Authors: Pongkitiwanichakul P. , Schaeffer D. B. , Fox W. , Ruffolo D. , Donaghy J. , Germaschewski K.
Published: January 2024

Magnetized collisionless shocks are common in astrophysical systems, and scaled versions can be created in laboratory experiments by utilizing laser-driven piston plasmas to create these shocks in a magnetized background plasma. A key parameter for these experiments is the angle θB between the shock propagation direction and the background magnetic field. We performed quasi-1D piston-driven shock simulations to explore shock formation, evolution, and key observables relevant to laboratory experiments for a range of shock angles between θB=90° to θB=30°. Our results show that the spatial and temporal scales of shock formation for all angles considered are similar when expressed in terms of the perpendicular component of the magnetic field. In a steady state, ion and electron temperatures become more isotropic, and the electron-to-ion temperature ratio is higher for smaller θB. At θB=30°, ion heating parallel to the magnetic field becomes dominant, associated with more ions being reflected at one discontinuity and subsequently trapped by the next discontinuity due to shock reformation.
Exploration of anomalous transport based on the use of general conformable fractional derivative in tokamak plasmas
Authors: Wu Kaibang , Liu Jiayan , Wang Feng , Wei Lai , Luan Qibin , Wang Zheng-Xiong
Published: January 2024

This study investigates anomalous transport in tokamak plasmas by employing general conformable fractional derivatives (GCFDs) and utilizing general conformable fractional diffusion equations (GCFDEs). GCFDs, which are local derivatives utilizing fractional conformable functions, exhibit properties similar to those of ordinary derivatives. The action can be defined by employing the definition of the inverse operation of GCFDs, and the general conformable fractional equation of motion (GCFEM) is derived through the calculus of variations. Introducing a damping term to the GCFEM results in the general conformable fractional Langevin equation (GCFLE). Solutions of the GCFLE indicate a scaling law for the mean squared displacement (MSD) ⟨x2⟩∝tα/Γ1+α, linking MSD scaling to the order α of the GCFD if the conformable fractional function ψt,α=Γαt1−α, where Γx is the gamma function. Therefore, the general conformable fractional diffusion coefficient (GCFDC) Dψ,α is defined as the ratio of the classical diffusion coefficient to ψt,α. From the definition of the running diffusion coefficient, it is found that when the Kubo number is much greater than unity, indicating that the system is in a turbulent state, both the classical and the GCFDC are inversely proportional to α—the power of the magnitude of the background magnetic field. After constructing a GCFDE based on the scaling law of MSD, it is applied to investigate the formation of hollow temperature profiles during off-axis heating in magnetically confined plasmas. Simulation results reveal the crucial role of the fractional conformable function in sustaining the long-term existence of these hollow temperature profiles as it can impede thermal conduction.
Enhanced photonic spin Hall effect and its sensing application via optical Tamm state based on nanocomposites
Authors: Dong Peng , Xu Jiahao , Cheng Jie
Published: January 2024

In this contribution, by combining the nanocomposite with distributed Bragg reflector, a simple multilayer structure to enhance the photonic spin Hall effect (PSHE) via optical Tamm state (OTS) for both horizontal (H) and vertical (V) polarized lights is presented. The structural parameters of nanocomposite layer (e.g., thickness and filling factor) have a significant influence on PSHE. The maximal spin shifts of 16.2 and 17.8 μm can be achieved for H and V polarized lights, respectively, which are attributed to strong excitation of OTS. Moreover, the spin shift is extremely sensitive to the refractive index changes of sensing medium, and a gas sensor with superior sensing performance is theoretically proposed for both H and V polarized beams. These findings provide an effective method to enhance the PSHE for both H and V polarized lights and therefore open an opportunity for developing PSHE refractive index sensors.
From toggle to precessional single laser pulse switching
Authors: Peng Y. , Malinowski G. , Kunyangyuen B. , Salomoni D. , Igarashi J. , Lin J. X. , Zhang W. , Gorchon J. , Hohlfeld J. , Buda-Prejbeanu L. D. , Sousa R. C. , Prejbeanu I. L. , Lacour D. , Mangin S. , Hehn M.
Published: January 2024

With the advent of nanotechnologies, it has been possible to extend the number of stimuli that can be used to control the state of a magnetic nanostructure. Among those stimuli, single laser pulse excitation allows, under certain conditions, to obtain energy-efficient ultrafast magnetization reversal. With this respect, two different types of single pulse switching mechanisms have been reported. The first one consists in a sub-picosecond ultrafast toggle switching, which was observed mainly in Gd based alloys. The second type relies on sub-nanosecond precessional switching occurring in rare earth–transition metal alloys/multilayers. Here, we demonstrate that single pulse all optical switching is achieved in Co68Tb32/Co100−xGdx/Co68Tb32 trilayers in which the behavior can be tuned from toggle to precessional by changing the composition of the Co100−xGdx alloy.
Point source modelling approach for sessile droplet evaporation
Authors: Malcolm Sophie , Azzam Ahmed , Amirfazli Alidad
Published: January 2024

Evaporation of sessile droplets from unheated solid surfaces is a ubiquitous process in many practical applications. A reduced order, analytical point source model (PSM) for the axisymmetric diffusion-dominated evaporation of an isolated sessile droplet surrounded by non-saturated, quiescent air was developed. The droplet is modeled as a dynamic point mass source in the limit of an isothermal system. The model also incorporates the spatial variation in the evaporative flux across the droplet free surface. The model is capable of considering the mode of evaporation, i.e., constant contact angle or contract radius. The PSM was simulated using the finite difference method in MATLAB R2020a. The model determines the vapor concentration distribution in the surrounding environment, the instantaneous evaporative flux averaged across the droplet surface and the overall evaporation rate. Calculating the evaporation rate assuming a spatially uniform evaporative flux under-predicts the evaporation rate by up to an order of magnitude. The model results agreed with experimental data in literature and sufficiently captures the evaporation process phenomena. The versatility and accurate predictive power of the PSM allows it to be a robust and computationally inexpensive modeling tool for studying sessile droplet evaporation in a wide range of technical applications.
Rational engineering of semiconductor-based photoanodes for photoelectrochemical cathodic protection
Authors: Chen Xiangyan , Wang Shaopeng , Shen Shaohua
Published: January 2024

Photoelectrochemical (PEC) cathodic protection based on semiconductor photoanodes, by combining solar energy utilization and metal anticorrosion, provides a promising platform for developing an environmentally friendly metal protection technology. In this context, semiconductors (e.g., TiO2, ZnO, SrTiO3, BiVO4, and g-C3N4), with merits of suitable band structure, good chemical stability, and low cost, have attracted extensive attention among the investigated photoanode candidates. However, the poor optical absorption properties and the high photogenerated charge recombination rate severely limit their photocathodic protection performances. In order to break these limitations, different modification strategies for these photoanodes have been developed toward the significant enhancement in PEC cathodic protection properties. In this Review, the rational engineering of semiconductor-based photoanodes, including nanostructure design, elemental doping, defect engineering, and heterostructure construction, has been overviewed to introduce the recent advances for PEC cathodic protection. This Review aims to provide fundamental references and principles for the design and fabrication of highly efficient semiconductor photoanodes for PEC cathodic protection of metals.
New rationale for the effect of multiple buoyancies and their influence on the propagation of respiratory pollutants
Authors: Deng Xiaorui , Gong Guangcai , He Xizhi , Wang Yuxin , Huang Yuting , Chen Xiang
Published: January 2024

The effect of buoyancy on fluid flows is a significant consideration in problems relating to energy, the environment, and health. Here, we examine what we term a “multi-buoyancy effect” (MBE), or “fluid-bunching effect,” which is a combination of the Archimedes number (Ar)-related buoyancy resulting from the temperature difference between a fluid flow and the ambient fluid and the Gc number (Gc)-related buoyancy resulting from the temperature difference between the upper and lower boundaries of the fluid domain. A new semi-analytical mathematical model of the jet trajectory is put forward by rational reconstruction. This reveals the physical mechanisms of fluid flows propagating in limited spaces under this MBE. Human respiratory experiments were conducted to show that the MBE can govern the transmission of infective airborne pollutants between people. Our findings provide a new perspective in the transmission of fluid flows and airborne pollutants in limited spaces. They are, thus, also of great interest for predicting the stratification of flows and circulation of the atmosphere and ocean.
Origin of brittle behavior of doped PbTe-based thermoelectric materials
Authors: Chepkasov Ilya V. , Kvashnin Alexander G. , Radina Aleksandra D. , Matsokin Nikita A. , Jalolov Faridun N. , Kvashnin Dmitry G. , Oganov Artem R. , Dashevsky Zinovi
Published: January 2024

Finding new efficient thermoelectric materials is a significant challenge for materials science. It is crucial to have a comprehensive understanding of material-property relationships to develop new materials successfully, given that minor structural or compositional changes can result in significant property changes. This paper extensively utilizes advanced theoretical approaches and investigates the impact of n- and p-type impurities on the mechanical characteristics of PbTe thermoelectric materials. n- and p-type doping of PbTe were studied using various techniques, including elastic tensor calculations, crystal orbital Hamilton population method, and local vibrational theory. Our findings reveal the specific ways in which doping type affects the material's mechanical properties. This information can aid researchers in optimizing PbTe doping strategies.
Shock wave prediction in transonic flow fields using domain-informed probabilistic deep learning
Authors: Mufti Bilal , Bhaduri Anindya , Ghosh Sayan , Wang Liping , Mavris Dimitri N.
Published: January 2024

Transonic flow fields are marked by shock waves of varying strength and location and are crucial for the aerodynamic design and optimization of high-speed transport aircraft. While deep learning methods offer the potential for predicting these fields, their deterministic outputs often lack predictive uncertainty. Moreover, their accuracy, especially near critical shock regions, needs better quantification. In this paper, we introduce a domain-informed probabilistic (DIP) deep learning framework tailored for predicting transonic flow fields with shock waves called DIP-ShockNet. This methodology utilizes Monte Carlo dropout to estimate predictive uncertainty and enhances flow-field predictions near the wall region by employing the inverse wall distance function-based input representation of the aerodynamic flow field. The obtained results are benchmarked against the signed distance function and the geometric mask input representations. The proposed framework further improves prediction accuracy in shock wave areas using a domain-informed loss function. To quantify the accuracy of our shock wave predictions, we developed metrics to assess errors in shock wave strength and location, achieving errors of 6.4% and 1%, respectively. Assessing the generalizability of our method, we tested it on different training sample sizes and compared it against the proper orthogonal decomposition (POD)-based reduced-order model (ROM). Our results indicate that DIP-ShockNet outperforms POD-ROM by 60% in predicting the complete transonic flow field.
Multi-scale analytical description of an expanding plasma slab
Authors: Cohen Itamar , Meir Talia , Elkind Michal , Catabi Tomer , Henis Zohar , Perelmutter Lior , Pomerantz Ishay
Published: January 2024

We present a new analytical model for the expansion of a thin slab of plasma into vacuum. By considering the rising plasma scale length during the initial heating phase, we were able to give the plasma a smooth quadratic behavior at the origin while describing its exponentially falling density at a large distance. We show this functional form to be a solution to the plasma equations and validate its predictions against numerical simulations and experimental measurements. We demonstrate the applicability of the model to experimental scenarios in which solid foils are turned into tens of micrometer-scale plasmas, to serve as targets for direct laser acceleration of electrons.
Pressure and chemical doping induced phase transition and phonon dynamics of multiferroic Bi5Ti3FeO15 ceramics
Authors: Bian Mengyun , Cui Anyang , Jiang Kai , Zhang Jinzhong , Zhu Liangqing , Shang Liyan , Li Yawei , Hu Zhigao
Published: January 2024

The external pressure and doping effect have been studied on the lattice structure of multiferroic Bi5Ti3−2xFe1+xNbxO15 (BTFNx) ceramics. Based on the x-ray diffraction and the Raman spectroscopic evidence, it is confirmed that the doping-induced lattice deformation is closely related to the concentrations of the Nb5+ and Fe3+ ions. The Bi5Ti3FeO15 (BTF) ceramic transits from orthorhombic (O, A21am) - O and tetragonal (T) - T (I4/mmm) with pressure, showing the intermediate phase coexistence at a wide pressure range of 4.5–14.8 GPa, while for BTFN0.6 ceramics, it is O (Fmm2) - O and T - T(I4/mmm) having the phase coexistence at 6–18 GPa. The ionic substitution, phase diagram and the evolution of phonon, lattice symmetry, and stability of BTFNx ceramics have been systematically observed and studied under the internal and external factors. Our work provides a comprehensive understanding of the structural and physical functionality for the development and optimization of multiferroic four-layer compounds BTF material systems.
An application of hybrid Taguchi-ANN to predict tool wear for turning EN24 material
Authors: Kamble Prashant D. , Giri Jayant , Makki Emad , Sunheriya Neeraj , Sahare Shilpa B. , Chadge Rajkumar , Mahatme Chetan , Giri Pallavi , T. Sathish , Panchal Hitesh
Published: January 2024

This work is an attempt to predict tool wear for turning EN24 material by the hybrid Taguchi-ANN (Taguchi-Artificial Neural Network) method. The objective is to minimize the tool wear. The independent factors are cutting environment, feed rate, depth of cut, nose radius, and tool type. A Spinner numerical control lathe is used to assess performance. As per the Taguchi orthogonal array, 27 experiments are conducted for each value of the uncontrollable factor (spindle vibration). Optimal setting is structured by Taguchi analysis and the response table. The additive model is used to predict the response. Conformity test is carried out to check whether the predicted and experimental values of response are within the range given by the confidence interval. Furthermore, the ANN is used to predict and analyze the tool wear. The result showed that the supremely important parameter is depth of cut and the least important parameter is tool type. The ideal set found is A3, B3, C3, D1, and E3. Through ANN analysis, it is observed that the experimental values are very close to the predicted values of tool wear. The predicted value at optimal setting is 0.0401 mm. The experimental values at optimal setting is 0.0422 mm. In addition, the study showed that when the feed rate and nose radius are both set to high levels and the depth of cut is medium, using an uncoated tungsten carbide tool with minimal lubrication results in the least amount of tool wear.
Diagnosis of DC series arc fault based on multiple wavelet transform and optimal fractional wavelet energy entropy
Authors: Yin Zhendong , Wang Li , Qiu Xianqun , Zhang Jiyong
Published: January 2024

In the DC distribution system, the propagation of arc noise can interfere with normal lines, and accurate and timely diagnosis of the location of series arc fault (SAF) is a challenging problem. In this article, a SAF diagnosis method is proposed from a system perspective, which can accurately identify the fault line. First, multiple wavelet transform is used to decompose the currents of different lines, and the fractional wavelet energy entropy is extracted to construct the feature vector. Then, random forest is employed to analyze the importance of features and to select the optimal features. Finally, a kernel extreme learning machine can fuse the features and output the diagnosis results. The offline experimental results indicate that the proposed method has a diagnosis accuracy of 99.82%, which is higher than those of nine comparison methods, and the effectiveness and advancement of the proposed method are verified. The online experimental results show that the proposed method can diagnose SAF within 110 ms, and the diagnosis speed is able to satisfy the requirements of UL1699B. Moreover, under transient conditions, the proposed method can effectively avoid false alarms and maintain stability.
Efficient single-run implementation of generalized Einstein relation to compute transport coefficients: A binary-based time sampling
Authors: Moustafa Sabry G. , Schultz Andrew J. , Douglas Jack F.
Published: January 2024

A robust and simple implementation of the generalized Einstein formulation using single equilibrium molecular dynamics simulation is introduced to compute diffusion and shear viscosity. The unique features underlying this framework are as follows: (1) The use of a simple binary-based method to sample time-dependent transport coefficients results in a uniform distribution of data on a logarithmic time scale. Although we sample “on-the-fly,” the algorithm is readily applicable for post-processing analysis. Overlapping same-length segments are not sampled as they indicate strong correlations. (2) Transport coefficients are estimated using a power law fitting function, a generalization of the standard linear relation, that accurately describes the long-time plateau. (3) The use of a generalized least squares (GLS) fitting estimator to explicitly consider correlations between fitted data points results in a reliable estimate of the statistical uncertainties in a single run. (4) The covariance matrix for the GLS method is estimated analytically using the Wiener process statistics and computed variances. (5) We provide a Python script to perform the fits and automate the procedure to determine the optimal fitting domain. The framework is applied to two fluids, binary hard sphere and a Lennard-Jones near the triple point, and the validity of the single-run estimates is verified against multiple independent runs. The approach should be applicable to other transport coefficients since the diffusive limit is universal to all of them. Given its rigor and simplicity, this methodology can be readily incorporated into standard molecular dynamics packages using on-the-fly or post-processing analysis.
Comment on “Transport coefficients for magnetic-field evolution in inviscid magnetohydrodynamics” [Phys. Plasmas 28, 012305 (2021)]
Authors: Lopez N. A.
Published: January 2024

A recent paper by Davies et al. [Phys. Plasmas 28, 012305 (2021)] presents rational interpolants for the resistive (α) and thermoelectric (β) transport coefficients as functions of the Hall parameter χ and the ion charge state Z. Here, this discussion is augmented by showing that, at least in the Lorentz limit Z→∞, the proposed rational interpolants for α⊥ and β⊥ can be made even more accurate over a larger range of χ by making slight modifications to ensure the exact asymptotic limits are preserved. Although the authors do not discuss the conductivity (κ) coefficients, this exercise can also be repeated for the rational interpolants of κ⊥ and κ∧ published in a similar work [Phys. Rev. Lett. 126, 075001 (2021)].
Phenotypic and genotypic variation in Australian native Sorghum species along aridity clines
Authors: Myrans Harry , McCausland Jack R. , Johnson Scott N. , Gleadow Roslyn M.
Published: January 2024

Context Wild sorghum taxa (Sorghum Moench) cover much of the northern Australian landscape and harbour potentially useful traits for crop improvement. Specialised metabolites such as phenolics, silicon and cyanogenic glucosides (which are toxic to grazing animals) are present in Sorghum and have been associated with drought tolerance. However, these taxa remain poorly studied, especially regarding intraspecific variation. Aims To investigate the intraspecific diversity of wild sorghums growing along aridity clines, including morphology, biochemistry and genotype. We hypothesised that genotypic and phenotypic diversity would co-vary with niche diversity. Methods Multiple accessions of Sorghum plumosum, S. stipoideum and S. timorense were grown under common conditions for 10 weeks. Concentrations of cyanogenic glucosides, phenolics and silicon were measured alongside five morphological traits. Accessions were genotyped using single-nucleotide polymorphisms. Key results Several traits varied significantly within species, but no trait consistently co-varied with aridity across species. In S. timorense, there appeared to be genotypic differentiation among accessions, but this was not translated into phenotypic differences, which was likely to be due to similarities in climate. Conclusions Our results challenge assumptions that phenotypic and genotypic diversity correlate with niche diversity and support the hypothesis that mature Australian wild sorghums store most of their cyanogenic glucosides in their roots. Implications Wild sorghums harbour advantageous traits for crop improvement, such as niche diversity and low toxicity. Future wild sorghum research must acknowledge intraspecific diversity, and as many populations as possible should be conserved, because genetic diversity is not necessarily discernible from phenotype or provenance alone.
Atterberg limits of baseball infield soils containing over-size particles, Part I: effect of particle size
Authors: Mascitti Evan Christopher , McNitt Andrew Scott , Drohan Patrick J.
Published: January 2024

Context The performance of baseball infield playing surfaces greatly depends on soil water content. Therefore, Atterberg limit tests may be useful when evaluating baseball infield soils because these tests directly link soil behaviour to water content. The tests’ utility for this application is limited by the standard practice of removing particles larger than 425 μm. Removing particles of 425–2000 μm makes it difficult to compare results for soils having different sand gradations because different amounts of sand are often removed. The implications of leaving particles of 425–2000 μm in the sample are not known. Aims This research was conducted to re-appraise the practice of removing ‘oversize’ particles prior to Atterberg limit testing and to clarify the oversize particles’ influence on the test results. Methods Six size grades of granular particles (termed ‘coarse additions’) corresponding to five individual size ranges of sand (2000–1000, 1000–500, 500–250, 250–150, and 150–53 μm) and silt (i.e. finer than 53 μm) were mixed with a kaolinitic clay at 0–80% coarse addition. The liquid limit (LL) and plastic limit (PL) were determined for each mixture. Key results The LL and PL decreased proportionally with sand or silt additions up to about 30% coarse content. Above 30%, particles finer than 425 μm produced greater deviations from the expected LL and PL than did the particles coarser than 425 μm, which would be prevented using current standard test methods. Conclusions Mixes containing these ‘oversize’ particles did not preclude the ability to complete the Casagrande cup or thread rolling tests, and in fact gave more predictable results than the currently-allowed particles, particularly those less than 250 μm in diameter. Implications This research suggests particles of 425–2000 μm can remain in soils during Atterberg limit tests. These findings may improve the utility of LL and PL tests for comparing baseball infield mixes.
On the (Non)Hadamard property of the SJ state in a
1+1
D causal diamond
Authors: Rocky Zhu Yifeng , Yazdi Yasaman K
Published: January 2024

The Sorkin–Johnston (SJ) state is a candidate physical vacuum state for a scalar field in a generic curved spacetime. It has the attractive feature that it is covariantly and uniquely defined in any globally hyperbolic spacetime, often reflecting the underlying symmetries if there are any. A potential drawback of the SJ state is that it does not always satisfy the Hadamard condition. In this work, we study the extent to which the SJ state in a

1
+
1

D causal diamond is Hadamard, finding that it is not Hadamard at the boundary. We then study the softened SJ state, which is a slight modification of the original state to make it Hadamard. We use the softened SJ state to investigate whether some peculiar features of entanglement entropy in causal set theory may be linked to its non-Hadamard nature.
Charged Lifshitz black holes from general covariance breaking
Authors: Moreira D C , Lemos A S , Brito F A
Published: January 2024

In this work we use a general covariance breaking mechanism to obtain a class of charged black holes whose background geometry asymptotically approaches Lifshitz spacetimes. We discuss how this method affects Einstein’s equations and explore the thermodynamics and critical behavior of the solution found.
Research on the influence of intra-cavity dispersion on pulse characteristics of a quartic soliton fiber laser
Authors: Wen Honglin , Liu Lie , Han Ying , Gao Xiaotong , Gu Haijun , Sun Yadong , Gao Bo
Published: January 2024

We numerically investigate the influence of higher-order dispersion on the dynamics of quartic solitons in a passively mode-locked fiber laser. The simulation results show that the output pulse characteristics of the quartic soliton fiber laser are not only affected by the intra-cavity net dispersion but also related to the position of the single-mode fiber (SMF). For different intra-cavity net higher-order dispersion values, the quartic soliton undergoes multiple alternations between the stable single soliton state and pulsating state in the fiber laser, and the number and intensity of Kelly sidebands in the output pulse spectrum are significantly different. For different positions of the SMF, the dynamics of the quartic soliton are also different. In addition, we also observe two types of novel pulsation-creeping behavior and time shift. These findings provide new insights into the output characteristics of quartic solitons in fiber lasers.
Inner-shell photoelectron spectroscopy unveils the interplay between hydrogen bonds and
π−π
stacking in clusters of biomolecules in the gas phase: hypoxanthine clusters as a case study
Authors: Barreiro-Lage Darío , Mattioli Giuseppe , Nicolafrancesco Chiara , Rousseau Patrick , Milosavljević Aleksandar R , Díaz-Tendero Sergio
Published: January 2024

We present a joint theoretical-experimental study on the inner-shell photoionization of hypoxanthine clusters in the gas phase. Simulations were performed using a computational strategy that combines molecular dynamics to explore the conformers of the clusters, density functional theory for geometry optimization and inner shell photoionization calculations. Two main intermolecular interactions are observed: hydrogen-bonds (HB) and

π
−
π

stacking. When increasing the cluster size, a combination of both kinds of interaction occurs. We show that such intermolecular interactions play a role in the chemical shift observed in X-ray photoemission spectroscopy experiments. In particular, we highlight the interplay between charge depletion and charge accumulation in regions where HBs stabilize the clusters.
GPS + 5G fusion for high-precision time transfer
Authors: Liu Mingyue , Tu Rui , Li Fangxin , Chen Qiushi , Li Qi , Chen Junmei , Zhang Pengfei , Lu Xiaochun
Published: January 2024

With the continuous development and increasing popularity of the fifth generation (5G) of mobile communications technology, its fusion with the Global Navigation Satellite System (GNSS) data can effectively improve problems with service interruptions or poor satellite signal reception. In this study, GPS and 5G data were fused, and the resulting experimental algorithm showed that it effective improves time transfer’s frequency stability and reliability. Moreover, this technique reduced the noise level of time-transmitted clock offset sequences, while suppressing short-term mutations. By simulating different degrees of satellite signal occlusion, it was further verified that the GPS + 5G fusion method can provide stable, high-precision, and real-time delivery services under complex occluded environments insufficient satellite signal reception. This provides a reference for high-precision time transfer technology in complex environments and further improves the reliability of GNSS high-precision time transfer.
Design and analysis of parallel six-dimensional force sensor based on near-singular characteristics
Authors: Cai Dajun , Yao Jiantao , Gao Weihua , Zhang Hongyu , Li Zeyu
Published: January 2024

The high sensitivity six-dimensional force sensor is the core component of intelligent robot force feedback perception, which is related to the structure of the sensor. This paper proposes a new modeling method to chain the near singular eight-branch Stewart mechanism, which indicates the relationship between structural parameters and sensitivity. The new method gains 16 new configurations by innovating the traditional Stewart institution. A configuration with high sensitivity in Fz, Mx and My directions is selected for further study. The theoretical stiffness model and force mapping model show that the sensitivity of the new structure can be amplified by 4 times in specific degrees of freedom. The results show that the nonlinear error and coupling error are 2.77% and 2.26%, respectively. The proposed method can be widely applied in the field of parallel six-dimensional force sensors.
Response of Mg2X (X = Si, Ge and Sn) compounds to extreme uniaxial compression: first-principles calculations
Authors: Behar Fatima Zohra , Meskine Said , Boukortt Abdelkader , Benbedra Abdesamed
Published: January 2024

In this study, we perform first-principles calculations using density functional theory to examine the structural, electronic, thermodynamic, and thermoelectric properties of the Mg2X (X = Si, Ge and Sn) compounds under uniaxial compression within the generalized gradient and modified Becke–Johnson approximations. It is found that the band gap of Mg2Si, Mg2Ge and Mg2Sn decreases with applied uniaxial pressure and changes its direction from Γ-X to Γ-K. The results of phonon frequencies indicate that the studied compounds are dynamically stable at zero and higher uniaxial strains. Furthermore, the uniaxial compression and temperature dependence of the Gibbs free energy, heat capacity and thermal expansion coefficient are investigated in the frame of the quasi-harmonic approximation. The semiclassical-Boltzmann method is used to study the Seebeck coefficient, electrical conductivity, thermal conductivity and figure of merit ZT as a function of both temperature and uniaxial pressure. It is shown that the Seebeck coefficient decreases with increasing pressure whereas thermal conductivity increases, which leads to the lowering in the value of ZT and thus to a worse thermoelectric performance of the studied materials.
Comparison of two methods simulating inter-track interactions using the radiobiological Monte Carlo toolkit TOPAS-nBio
Authors: Derksen Larissa , Adeberg Sebastian , Zink Klemens , Baumann Kilian-Simon
Published: January 2024

Objective. To compare two independently developed methods that enable modelling inter-track interactions in TOPAS-nBio by examining the yield of radiolytic species in radiobiological Monte Carlo track structure simulations. One method uses a phase space file to assign more than one primary to one event, allowing for inter-track interaction between these primary particles. This method has previously been developed by this working group and published earlier. Using the other method, chemical reactions are simulated based on a new version of the independent reaction time approach to allow inter-track interactions. Approach.
G-values were calculated and compared using both methods for different numbers of tracks able to undergo inter-track interactions. Main results. Differences in the G-values simulated with the two methods strongly depend on the molecule type, and deviations can range up to 3.9% (H2O2), although, on average, the deviations are smaller than 1.5%. Significance. Both methods seem to be suitable for simulating inter-track interactions, as they provide comparable G-values even though both techniques were developed independently of each other.
Interactive segmentation of medical images using deep learning
Authors: Zhao Xiaoran , Pan Haixia , Bai Wenpei , Li Bin , Wang Hongqiang , Zhang Meng , Li Yanan , Zhang Dongdong , Geng Haotian , Chen Minghuang
Published: January 2024

Medical image segmentation algorithms based on deep learning have achieved good segmentation results in recent years, but they require a large amount of labeled data. When performing pixel-level labeling on medical images, labeling a target requires marking ten or even hundreds of points along its edge, which requires a lot of time and labor costs. To reduce the labeling cost, we utilize a click-based interactive segmentation method to generate high-quality segmentation labels. However, in current interactive segmentation algorithms, only the interaction information clicked by the user and the image features are fused as the input of the backbone network (so-called early fusion). The early fusion method has the problem that the interactive information is much sparse at this time. Furthermore, the interactive segmentation algorithms do not take into account the boundary problem, resulting in poor model performance. So we propose early fusion and late fusion strategy to prevent the interaction information from being diluted prematurely and make better use of the interaction information. At the same time, we propose a decoupled head structure, by extracting the image boundary information, and combining the boundary loss function to establish the boundary constraint term, so that the network can pay more attention to the boundary information and further improve the performance of the network. Finally, we conduct experiments on three medical datasets (Chaos, VerSe and Uterine Myoma MRI) to verify the effectiveness of our network. The experimental results show that our network greatly improved compared with the baseline, and NoC@80(the number of interactive clicks over 80% of the IoU threshold) improved by 0.1, 0.1, and 0.2. In particular, we have achieved a NoC@80 score of 1.69 on Chaos. According to statistics, manual annotation takes 25 min to label a case(Uterine Myoma MRI). Annotating a medical image with our method can be done in only 2 or 3 clicks, which can save more than 50% of the cost.
Hydrophilic and hydrophobic shape memory polymer networks in high-intensity focused ultrasound fields
Authors: Xi Jiaxin , Sallam Ahmed , Safranski David L , Mirzaeifar Reza , Shahab Shima
Published: January 2024

High-intensity focused ultrasound (HIFU) has been investigated as a remote and controlled activation method to noninvasively actuate shape memory polymers (SMPs), specifically in biomedical applications. However, the effects of aqueous environment on shape recoverability of in vivo HIFU-actuated SMPs have yet to be explored. HIFU directs sound waves into a millimeter-sized tightly focused region. In this study, the response of hydrophilic and hydrophobic photopolymerized thermoset SMP networks under HIFU activation in an aqueous environment was investigated. Acrylate-based SMP networks were copolymerized in specific ratios to produce networks with independently adjusted glass transition temperatures ranging from 40 to 80 °C and two distinct water uptake behaviors. The results link the polymer swelling behavior to shape recoverability in various acoustic fields. The presence of absorbed water molecules enhances the performance of SMPs in terms of their shape memory capabilities when activated by HIFU. Overall, understanding the interplay between water uptake and HIFU-actuated shape recovery is essential for optimizing the performance of SMPs in aqueous environments and advancing their use in various medical applications.
Modeling of rigidly-constrained pure shear dielectric elastomer actuators: electromechanical coupling network method
Authors: Sun Wenjie , Liang Huwei , Zhang Fei , Wang Chenyang , Li Bo
Published: January 2024

The rigidly-constrained pure shear dielectric elastomer actuator (PS-DEA) has become one of the critical configurations in linear soft actuator design due to its excellent uni-directional actuation performance and convenient preparation process. However, the theoretical analyses are primarily conducted by employing ideal models and lack consideration of the lateral necking deformation of PS-DEA, which has an essential impact on the performance evaluation and optimal design of PS-DEA. Therefore, in this paper, a user subroutine that describing the behavior of the electromechanical behavior of DE in terms of the Gent free-energy model is developed, and then a parametric model of the PS-DEA is established. Different combinations of actuator parameters are obtained by Latin hypercube sampling, and the actuator’s performance under the parameters is simulated by the finite element method. The finite element results are taken as a sample set, and a BP neural network with three hidden layers is employed to train the samples and obtain a PS-DEA network prediction model, which is experimentally analyzed to validate its accuracy and effectiveness. The prediction model explores the influence of geometric and pre-stretching parameters on the actuator’s performance and obtains the difference between the ideal theoretical and the network prediction model under various parameters. The method in this paper provides a new design methodology and theoretical basis for developing high-performance DE actuators.
Hill-top inflation from Dai-Freed anomaly in the standard model — a solution to the iso-curvature problem of the axion dark matter
Authors: Kawasaki Masahiro , Yanagida Tsutomu T.
Published: January 2024

The discrete symmetry Z
4 in the standard model (SM) with three right-handed neutrinos is free from the Dai-Freed anomaly.
Motivated by this Z
4 symmetry, we constructed a topological inflation model consistent with all known constraints and observations.
However, we assumed a specific inflaton potential in the previous work.
In this paper we extend the inflaton potential in a more general form allowed by the discrete Z
4 gauge symmetry and show that consistent hilltop inflation is realized.We find that the Hubble parameter H_inf can be smaller than ≃ 109 GeV so that the isocurvature fluctuations of the axion dark matter are sufficiently suppressed.
Furthermore, the running of the spectral index can be as large as dns
/ln k ≃ 0.0018 which will be tested in future CMB observations.
Since this discrete Z
4 acts on the SM, the inflaton can couple to pairs of the right-handed neutrinos and hence the reheating temperature can be high as ∼ 1010 GeV, producing the cosmic baryon asymmetry naturally through the thermal leptogenesis.
Shelf-life prediction of nutmeg candy (myristica fragrans houtt) using the Arrhenius equation approach’s accelerated shelf-life testing (ASLT) method
Authors: Sulaiman I , Armita D Y , Erika C
Published: January 2024

Nutmeg (Myristica fragrans Houtt) is one of the spices utilized as food. The processing of nutmeg into sweets makes one of the snacks known as nutmeg candy. The nutmeg candy found in the market still does not have the identity product shelf life or expiration date, so buyers are hesitant; in this study, a simulation of estimating the shelf life of nutmeg candy with the Accelerated Shelf-Life Testing (ASLT) method was made and applied using Visual Basic applications which can later be used by industry and enterprise. Samples were taken from UMKM UD. Cahaya in Tapaktuan, South Aceh. This research was conducted by formulating temperatures of 35, 45, and 55°C with water and sugar content measurements; in this study, one critical point was taken to determine the shelf life. The results showed that the water content was 6.85 – 13.69 (%b/b), and the sugar content was 5.10-7° brix. The shelf life measured by the critical point shows that dried candied nutmeg can be stored for 50.89 days.