bluuebunny/crossref_metadata_2025 huggingface dataset:
Multifrequency topological interface modes in a nonlocal acoustic system with large winding numbers
Authors: Sun Yimeng , Wang Linjuan , Wang Jianxiang
Published: April 2024

Topological interface states have wide applications for their robustness and energy localization. Multiple topological interface states in 1D acoustic systems are preferred for signal enhancement at specific frequencies. However, previous 1D topological systems with local interactions can realize only one topological interface state in a bandgap. Here, we find that connected acoustic Su–Schrieffer–Heeger (SSH) chains with nonlocal interactions can achieve two or more topological interface states at different frequencies in a single bandgap, even in the subwavelength region. The difference in frequency can be modulated by merely adjusting the structural design at the interface. A mechanical metamaterial with a large winding number is designed to realize multiple nondegenerate topological interface states. This metamaterial can enhance weak acoustic signals at multiple specific frequencies simultaneously and has applications in the fields of acoustic detecting and color imaging.
Prediction of the univariant two-phase coexistence line of the tetrahydrofuran hydrate from computer simulation
Authors: Algaba Jesús , Romero-Guzmán Cristóbal , Torrejón Miguel J. , Blas Felipe J.
Published: April 2024

In this work, the univariant two-phase coexistence line of the tetrahydrofuran (THF) hydrate is determined from 100 to 1000 bar by molecular dynamics simulations. This study is carried out by putting in contact a THF hydrate phase with a stoichiometric aqueous solution phase. Following the direct coexistence technique, the pressure is fixed, and the coexistence line is determined by analyzing if the hydrate phase grows or melts at different values of temperature. Water is described using the well-known TIP4P/Ice model. We have used two different models of THF based on the transferable parameters for phase equilibria-united atom approach (TraPPE-UA), the original (flexible) TraPPe-UA model and a rigid and planar version of it. Overall, at high pressures, small differences are observed in the results obtained by both models. However, large differences are observed in the computational efforts required by the simulations performed using both models, being the rigid and planar version much faster than the original one. The effect of the unlike dispersive interactions between the water and THF molecules is also analyzed at 250 bar using the rigid and planar THF model. In particular, we modify the Berthelot combining rule via a parameter ξO-THF that controls the unlike water–THF dispersive interactions. We analyze the effect on the dissociation temperature of the hydrate when ξO-THF is modified from 1.0 (original Berthelot combining rule) to 1.4 (modified Berthelot combining rule). We use the optimized value ξO-THF = 1.4 and the rigid THF model in a transferable way to predict the dissociation temperatures at other pressures. We find excellent agreement between computer simulation predictions and experimental data taken from the literature.
Exploring the effect of the inlet gas volume fraction on the energy-conversion features of a multiphase pump using energy-transport theory
Authors: Wen Haigang , Tang Manqi , Lv Wenjuan , Shi Guangtai
Published: April 2024

This work sought to reveal the role of the inlet gas volume fraction (GVF) on the energy-conversion features of a multiphase pump. To this end, a self-developed single-stage multiphase pump was used as the research object, and a gas–liquid transport medium was examined based on the energy-transport theory. The role of the GVF in the pressure-gradient work, Lamb-vector divergence, and vortex pseudo-energy dissipation in the pressurization unit of the multiphase pump were analyzed, and the impact of the GVF on the energy-conversion features of the multiphase pump was also investigated. The results indicate that under various GVFs, increasing the tip clearance prevents the pressure gradient from exerting its intended function. Furthermore, as the GVF is increased, the scale of the tip-leakage vortex increases, the flow field in the pressurization unit is disturbed, and the vortex pseudo-energy dissipation in the impeller increases. As a result, the energy loss increases, the pressurization effect of the pump is weakened, and its work performance decreases. These results offer a reference for enhancing the efficiency of multiphase pumps.
Septin-coated microtubules promote maturation of multivesicular bodies by inhibiting their motility
Authors: Robinson Benjamin P. , Bass Naomi R. , Bhakt Priyanka , Spiliotis Elias T.
Published: April 2024

The microtubule cytoskeleton consists of microtubule subsets with distinct compositions of microtubule-associated proteins, which instruct the position and traffic of subcellular organelles. In the endocytic pathway, these microtubule-associated cues are poorly understood. Here, we report that in MDCK cells, endosomes with multivesicular body (MVB) and late endosome (LE) markers localize preferentially to microtubules coated with septin GTPases. Compared with early endosomes, CD63-containing MVBs/LEs are largely immotile on septin-coated microtubules. In vitro reconstitution assays revealed that the motility of isolated GFP-CD63 endosomes is directly inhibited by microtubule-associated septins. Quantification of CD63-positive endosomes containing the early endosome antigen (EEA1), the Rab7 effector and dynein adaptor RILP or Rab27a, showed that intermediary EEA1- and RILP-positive GFP-CD63 preferentially associate with septin-coated microtubules. Septin knockdown enhanced GFP-CD63 motility and decreased the percentage of CD63-positive MVBs/LEs with lysobiphosphatidic acid without impacting the fraction of EEA1-positive CD63. These results suggest that MVB maturation involves immobilization on septin-coated microtubules, which may facilitate multivesiculation and/or organelle–organelle contacts.
Rigid covalent bond of α-sulfur investigated via temperature-dependent EXAFS
Authors: Ikemoto Hiroyuki , Miyanaga Takafumi , Saiful Islam Md , Kawaguchi Reo
Published: April 2024

This study performs extended x-ray absorption fine structure (EXAFS) measurements for the S-K edge in the temperature range of 10 and 300 K in the transmission mode using a photodiode to detect the transmitted x-rays. It provides the first report of temperature variations in the structural parameters of α-S. As the temperature increases from 10 to 300 K in the Fourier transform of

k
χ
(
k
)

the first peak corresponding to the covalent bond of the eight-membered ring becomes slightly low anomalously despite thermal disturbances. However, as in normal materials, the second peak at 300 K decreases to approximately half of that at 10 K, which contains several intra- and inter-ring correlations. All structural parameters of the covalent bond obtained by nonlinear least squares fitting exhibit missing temperature variations. A value of zero for the asymmetric parameter in the EXAFS (C
3) implies that the potential of the covalent bond is symmetric, and the constant value of the mean square relative displacement (MSRD) with temperature implies that the potential is extremely high. The Einstein model fitting for the temperature variation in the MSRD yields an Einstein temperature of 942 K and force constant (K) of 405 N m−1. The value of K is the largest among those of chalcogen elements.
Magic-angle twisted bilayer graphene under orthogonal and in-plane magnetic fields
Authors: Bigeard Gaëlle , Cresti Alessandro
Published: April 2024

We investigate the effect of a magnetic field on the band structure of bilayer graphene with a magic twist angle of 1.08∘. The coupling of a tight-binding model and the Peierls phase allows the calculation of the energy bands of periodic two-dimensional systems. For an orthogonal magnetic field, the Landau levels are dispersive, particularly for magnetic lengths comparable to or larger than the twisted bilayer cell size. A high in-plane magnetic field modifies the low-energy bands and gap, which we demonstrate to be a direct consequence of the minimal coupling.
Hydrogen evolution descriptors of 55-atom PtNi nanoclusters and interaction with graphite
Authors: Ahlstedt Olli , Akola Jaakko
Published: April 2024

Density functional simulations have been performed for Pt
n
Ni

55
−
n

clusters (

n
=
0
,
12
,
20
,
28
,
42
,
55

) to investigate their catalytic properties for the hydrogen evolution reaction (HER). Starting from the icosahedral

Pt

12

Ni

43

, hydrogen adsorption energetics and electronic d-band descriptors indicate HER activity comparable to that of pure

Pt

55

(distorted reduced core structure). The PtNi clusters accommodate a large number of adsorbed hydrogen before reaching a saturated coverage, corresponding to 3–4 H atoms per icosahedron facet (in total ∼70–80). The differential adsorption free energies are well within the window of

|
Δ

G

H

|

<
0.1

 eV which is considered optimal for HER. The electronic descriptors show similarities with the platinum d-band, although the uncovered PtNi clusters are magnetic. Increasing hydrogen coverage suppresses magnetism and depletes electron density, resulting in expansion of the PtNi clusters. For a single H atom, the adsorption free energy varies between −0.32 (

Pt

12

Ni

43

) and −0.59 eV (

Pt

55

). The most stable adsorption site is Pt–Pt bridge for Pt-rich compositions and a hollow site surrounded by three Ni for Pt-poor compositions. A hydrogen molecule dissociates spontaneously on the Pt-rich clusters. The above HER activity predictions can be extended to PtNi on carbon support as the interaction with a graphite model structure (w/o vacancy defect) results in minor changes in the cluster properties only. The cluster-surface interaction is the strongest for

Pt

55

due to its large facing facet and associated van der Waals forces.
FGO-MFI: factor graph optimization-based multi-sensor fusion and integration for reliable localization
Authors: Zhu Jiaqi , Zhuo Guirong , Xia Xin , Wen Weisong , Xiong Lu , Leng Bo , Liu Wei
Published: April 2024

Reliable and precise information pertaining to the position, velocity, and attitude is essential for automated driving. This paper proposes FGO-MFI, a cost-effective and robust multi-sensor fusion and integration localization framework that utilizes factor graph optimization. Firstly, a tightly coupled Global Navigation Satellite Systems (GNSS)/on-board sensor fusion localization framework is established to estimate vehicle states, including position, velocity, and attitude. To address the large drift rate of the Inertial Measurement Unit (IMU), this study introduces a novel IMU/Dynamics pre-integration method based on the vehicle dynamics model. We establish a two-degree-of-freedom vehicle dynamics model utilizing measurements from the wheel speed sensor and steering wheel angle sensor. The IMU/Dynamics factor is devised through a close integration of the model output and IMU pre-integration, enabling the construction of precise odometry with low-cost on-board sensors. Then, to address the issue of the non-Gaussian distribution of GNSS pseudorange error, this paper employs a Gaussian Mixture Model (GMM) to characterize the pseudorange noise, which is then applied to further sensor fusion. Given the time-varying nature of pseudorange noise, the expectation maximization algorithm is utilized to estimate GMM parameters online, leveraging the pseudorange residuals within a sliding window. Comprehensive experiments, inclusive of challenging scenarios such as urban canyons, tunnels, and wooded areas, have been carried out. They affirm the superior performance of the proposed method. Experiments have shown that our method demonstrates reliable localization across different statuses of GNSS signal, exhibiting a 39.4% improvement in the root mean square error of position error when compared to the state-of-the-art. Additionally, this FGO-MFI is a general sensor data fusion framework and is able to incorporate diverse sensor measurements, for example, from cameras and LiDARs to provide more reliable and accurate localization information.
An autonomous and high-accuracy gravity disturbance compensation scheme for rotary inertial navigation system
Authors: Yang Jie , Wang Xinlong , Wang Bin , Hu Xiaodong
Published: April 2024

With the increasing demands for long-endurance and high-accuracy inertial navigation system (INS), gravity disturbance has been identified as one of the major error sources with decisive effects on the performance of INS. To address the problem, this paper proposes an autonomous and high-accuracy gravity disturbance compensation scheme for rotary INS (RINS). The high-accuracy velocity measured by the laser Doppler velocimeter is fused with the angular velocity measured by the gyroscope to obtain navigation parameters, such as velocity, position and attitude, that are not affected by gravity disturbance. The navigation parameters independent of gravity disturbance are matched with the gravity disturbance-related navigation parameters output by RINS, and a measurement model containing gravity disturbance information is obtained. Besides, the intrinsic coupling relationship between gravity disturbance, gravity disturbance rate and gravity disturbance gradient is revealed, and a state-space model is established to accurately reflect the time-varying characteristics of gravity disturbance. Furthermore, the gravity disturbance is estimated and compensated in real-time through the optimal estimation algorithm. The results of vehicle experiments indicate that the gravity disturbance estimation precision of the proposed scheme is better than 2.15 mGal (1σ), and its horizontal position accuracy is better than 50 m at a driving distance of 80 km.
Automated measurement of smartphone screen scratches using visual methods
Authors: Zhao Baigan , Yao Jiannan , Yu Bolong , Zhang Xudong , Lv Bo , Zhang Yue
Published: April 2024

Quantitative measurement of smartphone screen scratches is crucial for pricing in the used smartphone market. Traditional manual visual inspection methods suffer from inherent limitations, namely being labor-intensive, subjective, and prone to inaccuracy. Hence, this study proposes a vision-based measurement method as a viable solution to overcome these challenges. The algorithm uses the Hessian enhancement to extract scratch features, applies adaptive thresholding to distinguish features from the background, and employs morphological reconstruction to reconstruct complete scratches. The topological analysis splits and mergers intersecting scratches, enabling individual segmentation. Finally, four metrics for measuring screen scratches include length, brightness, contrast, and maximum width to quantitatively characterize the damage of screen scratches. Experiments showed that the proposed algorithm outperforms other vision-based methods, with an accuracy of 99.6% in estimating the scratch length and a running time of 43.7 ms, which fully meets the efficiency and accuracy requirements of industrial application.
A GPU based accelerated solver for simulation of heat transfer during metal casting process
Authors: Jayakumar Rahul , Rajan T P D , Savithri Sivaraman
Published: April 2024

The metal casting process, which is one of the key drivers of the manufacturing industry, involves several physical phenomena occurring simultaneously like fluid flow, phase change, and heat transfer which affect the casting yield and quality. Casting process modeling involves numerical modeling of these phenomena on a computer. In recent decades, this has become an inevitable tool for foundry engineers to make defect-free castings. To expedite computational time graphics processing units (GPUs) are being increasingly used in the numerical modeling of heat transfer and fluid flow. Initially, in this work a CPU based implicit solver code is developed for solving the 3D unsteady energy equation including phase change numerically using finite volume method which predicts the thermal profile during solidification in the metal casting process in a completely filled mold. To address the computational bottleneck, which is identified as the linear algebraic solver based on the bi-conjugate gradient stabilized method, a GPU-based code is developed using Compute Unified Device Architecture toolkit and was implemented on the GPU. The CPU and GPU based codes are then validated against a commercial casting simulation code FLOW-3D CAST® for a simple casting part and against in-house experimental results for gravity die casting of a simple geometry. Parallel performance is analyzed for grid sizes ranging from 10 × 10 × 10 to 210 × 210 × 210 and for three time-step sizes. The performance of the GPU code based on occupancy and throughput is also investigated. The GPU code exhibits a maximum speedup of 308× compared to the CPU code for a grid size of 210 × 210 × 210 and a time-step size of 2 s.
Size effects on spinodal decomposition
Authors: Petsos George
Published: April 2024

We examine the influence of grains size on the stability of polycrystalline coherent binary solid solutions. By assuming that the grains are isotropic, we find that the tendency for instability decreases as the radius of the grains decrease. We also find that a temperature-dependent critical grain radius exists below which the tendency for instability vanishes and the grains are stable, with respect to infinitesimal composition fluctuations, for any initial composition. We find that the critical grain radius decreases monotonically as the temperature decrease. If the radius of the grains is smaller than the minimum critical grain radius the grains are stable for any temperature and initial composition.
Optoelectronic and photocatalytic behaviour of a type-II GaAlS2/HfS2 heterostructure: ab initio study
Authors: Mehta Disha , Naik Yashasvi , Modi Nidhi , Parmar P R , Thakor P B
Published: April 2024

Theoretical examination based on first principle computation has been conducted for van der Waals heterostructure (vdwHS) GaAlS2/HfS2 including structural, optoelectronic and photocatalytic characteristics. From the adhesion energy calculation, the AB configuration of GaAlS2/HfS2 vdwHS is the most stable. A type-II GaAlS2/HfS2 vdwHS is a dynamically and thermally stable structure. The band edge position, projected band, and projected charge densities verify the type-II alignment of GaAlS2/HfS2 vdwHS. For GaAlS2/HfS2, GaAlS2 is acting as a donor and HfS2 is acting as an acceptor ensured by the charge density difference plot. The electron localized function validates the weak van der Waals interaction between GaAlS2 and HfS2. The GaAlS2/HfS2 vdwHS possess an indirect bandgap of 1.54 eV with notable absorption in the visible range. The findings assure that the GaAlS2/HfS2 vdwHS is an efficient photocatalyst for pH 4–8. The band alignment of GaAlS2/HfS2 is suitable for Z-scheme charge transfer. The strain influenced band edge suggests that the GaAlS2/HfS2 vdwHS remains photocatalytic for strain

−
4
%

to

+
6
%

in both cases of uniaxial and biaxial strains.
Illuminating dark matter: II. A guide for physics teachers
Authors: Pinochet Jorge
Published: April 2024

Dark matter is one of the great mysteries of contemporary science. In the first part of this work, we covered some general concepts that will serve as an introduction to the more specific topics analysed in this second part, such as the hypothetical particles that could constitute dark matter, and the experiments and detection techniques that have been implemented.
An overview of ion-acoustic solitary and shock waves in a magnetized nonthermal plasma: influence of trapped positrons and electrons
Authors: Habib K , Hassan M R , Alam M S , Sultana S
Published: April 2024

A magnetized nonthermal electron–positron-ion (e-p-i) plasma is considered to study the propagation properties of ion-acoustic solitary and shock waves in the presence of trapped positrons and electrons for the first time. The Schamel-κ (kappa) distribution function that describes plasma nonthermality and particle trapping is assumed to consider electrons and positrons. The diffusive effect of ion plasma fluid, which is responsible for shock dynamics, is taken into account. A nonlinear Schamel-Korteweg–de Vries-Burgers’ (SKdVB) equation is derived by employing the reductive perturbation approach, and the solitary and shock wave solutions of the SKdVB equation have also been derived for different limiting cases. It is found that only positive potential nonlinear structures (for both solitary and shock waves) are formed in the proposed plasma system. The condition for stable solitons in the absence of dissipation is analyzed, and the nature of arbitrary amplitude solitary waves (obtained via the Sagdeev potential approach) is discussed. It is found through theoretical and numerical investigation that different plasma compositional parameters (such as the trapping effect of electrons (β

e
) and positrons (β

p
), the obliquity effect (θ), electron-to-ion number density ratio (µ

e
), the magnetic field effect (via Ω) and the viscous effect (via η)) have a significant influence on the dynamics of ion-acoustic solitary and shock waves. The theoretical and numerical investigations in this study may be helpful in describing the nature of localized structures in different plasma contexts, e.g. space and astrophysical plasmas and experimental plasmas where electron–positron-ion plasmas exist.
Chasing the multi-modal plasma response in MAST-U
Authors: Munaretto S , Liu Y Q , Ryan D A , Hao G Z , Berkery J W , Blackmore S , Kogan L
Published: April 2024

Achieving edge localized modes (ELMs) suppression in spherical tokamaks by applying resonant magnetic perturbations (RMPs) has proven challenging. The poloidal spectrum of the applied RMP is a key parameter that has an impact on the capability to mitigate and eventually suppress ELMs. In this work the resistive magnetohydrodynamic code MARS-F (Liu et al 2000 Phys. Plasmas
7 3681) is used to evaluate the possibility of directly measuring the plasma response in MAST-U, and particularly its variation as function of the applied poloidal spectrum, in order to guide the experimental validation of the predicted best RMP configuration for ELM suppression. Toroidal mode number n = 2 RMP is considered to minimize the presence of sidebands, and to avoid the deleterious core coupling of n = 1. Singular Value Decomposition is used to highlight linearly independent structures in the simulated magnetic 3D fields and how those structures can be measured at the wall where the magnetic sensors are located. Alternative ways to measure the multimodal plasma response and how they can be used to infer the best RMP configuration to achieve ELM suppression are also presented, including the plasma displacement and the 3D footprints at the divertor plates.
The effect of divertor particle sources on scrape-off-layer turbulence
Authors: Xia Q , Moulton D , Omotani J , Militello F
Published: April 2024

Tokamak edge turbulence is crucial for the cross-field transport of particles and energy away from the separatrix. A better understanding of what affects the turbulence helps to control the heat flux to the divertor targets and the wall. One potentially important factor is the ion particle source in the divertor, as the neutral pathways and the ionisation source distributions are different depending on the divertor geometry, e.g. vertical- and horizontal-target configurations. Numerically, how to represent the sources and mimic the effects on the SOL in the simulations is still an open question. In this paper, we use a 3D turbulence code STORM, based on drift-reduced Braginskii equations, to study the effects of the divertor particle source distribution on turbulence in a simplified 3D slab geometry. The results show that it requires a large amount of divertor particle source to be peaked near the separatrix to alter the heat flux deposited on the target in attached conditions. This large non-uniform particle source can locally enhance the turbulence in the divertor volume, which redistributes the energy flux to the target and reduces the maximum amplitude. Meanwhile, the plasma profiles evaluated at the outboard midplane, such as the amplitudes and fluctuations of the density and temperature, are marginally changed. Another consequence of our results is that the prediction of the temperature difference between the outboard midplane and the target would be underestimated, if the calculation only considers the conductive heat flux and ignores this enhanced cross-field transport in the divertor.
The influence of thermo-electromechanical coupling on the performance of lead-free BNT-PDMS piezoelectric composites
Authors: Akshayveer  , Buroni Federico C , Melnik Roderick , Rodriguez-Tembleque Luis , Saez Andres , Singh Sundeep
Published: April 2024

In recent times, there have been notable advancements in haptic technology, particularly in screens found on mobile phones, laptops, light-emitting diode (LED) screens, and control panels. However, it is essential to note that the progress in high-temperature haptic applications is still in the developmental phase. Due to their complex phase and domain structures, lead-free piezoelectric materials such as

Bi

0.5

Na

0.5

TiO

3

(BNT)-based haptic technology behave differently at high temperatures than in ambient conditions. Therefore, it is essential to investigate the aspects of thermal management and thermal stability, as temperature plays a vital role in the phase and domain transition of BNT material. A two-dimensional thermo-electromechanical model has been proposed in this study to analyze the thermal stability of the BNT-PDMS composite by analyzing the impact of temperature on effective electromechanical properties and mechanical and electric field parameters. However, the thermo-electromechanical modelling of the BNT-PDMS composite examines the macroscopic effects of the applied thermal field on mechanical and electric field parameters, as phase change and microdomain dynamics are not considered in this model. This study analyzes the impact of thermo-electromechanical coupling on the performance of the BNT-PDMS composite compared to conventional electromechanical coupling. The results predicted a significant improvement in piezoelectric response compared to electromechanical coupling due to the increased thermoelectric effect in the absence of phase change and microdomain switching for temperature boundary conditions below depolarization temperature (

T
d

∼
200

∘

C for pure BNT material).
Design, modelling and experiments on a multisource energy harvester based on a single ferroelectric ceramic
Authors: Huang Jiahan , Jiang Chengbin , An Mingyi , Hu Pengfei , Xie YiYuan , Li Lingfeng , Chen Yu
Published: April 2024

Energy harvesting is a promising technique that can provide renewable and clean energy for the wireless sensor nodes. However, the solar, mechanical and thermal energies in our living environment are not always available due to the day/night, the weather and working conditions. Therefore, energy harvesting for a single energy source cannot provide a stable and continuous energy supply. Here, a multisource energy harvester based on a single material/structure (PLZT-Sb) is presented for scavenging solar, thermal, and mechanical energies simultaneously or individually. And then the output energy mathematical model is established and proved experimentally. The enhanced energy generations with the peak voltage of 1.9 kV and peak current of 200 nA are achieved by the unique integration of multi-effects, which can drive 139 LEDs. This work demonstrates an innovative approach for developing multisource energy harvester in a single ferroelectric material on the basis of the coupled multi-physics fields.
Necessary condition for information transfer under simulated parity-time-symmetric evolution
Authors: Lakkaraju Leela Ganesh Chandra , Mal Shiladitya , Sen (De) Aditi
Published: April 2024

Parity-time

(
P
T
)

symmetric quantum theory can broaden the scope of quantum dynamics beyond unitary evolution which may lead to numerous counter-intuitive phenomena, including single-shot discrimination of non-orthogonal states, faster evolution of state than the standard quantum speed limit, and violation of no-signaling principle. On the other hand,

P
T

-symmetric evolution can be realized as reduced dynamics of a subsystem in real experiments within the scope of standard QT. In this experimental setup, if one side of a composite system is evolved according to a

P
T

-symmetric way, a non-trivial information transfer can happen, i.e. the operation performed at one side can be gathered by the other side. By considering an arbitrary shared state between two parties situated in two distant locations and arbitrary measurements, we show that the

P
T

-symmetric evolution of the reduced subsystem at one side is not sufficient for this information transfer to occur. Specifically, we prove that the information transfer can only happen when the density matrix and the corresponding measurements contain complex numbers. Moreover, we connect the entanglement content of the shared state with the efficacy of information transfer. We find evidence that the task becomes more efficient with the increase of dimension.
Two port high gain and low mutual coupling dielectric resonator based array antenna for 5G mm-wave applications
Authors: Sikandar  , Dutta Kailash Pati , Tomar Geetam Singh , Katiyar Himanshu , Sharma Anand
Published: April 2024

In this communication, a two-port ceramic based array radiator at mm-wave frequency range is structured and analysed. 3-dB power divider based microstrip feed line is utilised to excite the rectangular aperture. The same aperture is used to feed the ceramic, which creates fundamental hybrid mode (HEM11δ
) inside the dielectric resonator. Feeding structure is designed on RT Duroid substrate having thickness 0.254 mm and permittivity 2.2. The length and width of the substrate is 60.0 mm and 30.0 mm respectively. Alumina material is used to design the ceramic having permittivity 9.8. The exclusive feature of the proposed antenna design is to get highly directional pattern along with high gain (more than 13.5 dBi) in mm-wave frequency range with the assistance of 1*4 array structure. Orthogonal orientation of antenna ports adds the polarization diversity concept, which in turns improve the isolation level more than 50 dB. Measured results confirm that the designed antenna works effectively in between 31.5–32.8 GHz. Broadside radiation pattern and good value of Envelop correlation coefficient (less than 0.1)/Diversity gain (10.0 dB) make the designed antenna employable for n257 frequency band of 5G mm-wave applications.
Core and halo properties in multi-field wave dark matter
Authors: van Dissel Fabio , Hertzberg Mark P. , Shapiro Jared
Published: April 2024

In this work, we compute multi-field core and halo properties in wave Dark Matter models. We focus on the case where Dark Matter consists of two light (real) scalars, interacting gravitationally. As in the single-field Ultra Light Dark Matter (ULDM) case, the scalar field behaves as a coherent BEC with a definite ground state (at fixed total mass), often referred to in the literature as a gravitational soliton. We establish an efficient algorithm to find the ground and excited states of such two-field systems. We then use simulations to investigate the gravitational collapse and virialization, starting from different initial conditions, into solitons and surrounding halo. As in the single-field case, a virialized halo forms with a gravitational soliton (ground state) at the center. We find some evidence for an empirical relation between the soliton mass and energy and those of the host halo. We use this to then find a numerical relation between the properties of the two. Finally, we use this to address the issue of alleviating some of the tensions that single-field ULDM has with observational data, in particular, the issue of how a galaxy's core and radius are related. We find that if galaxies of different masses have similar percentages of the two species, then the core-radius scaling tension is not addressed. However, more general possibilities occur if the relative abundance of species in each halo correlates with the total mass of the galaxy. If this is the case, the model predicts several other phenomenological signatures.
Integrated analysis of plasma rotation effect on HL-3 hybrid scenario
Authors: Xue 薛 Miao 淼 , Zheng 郑 Guo-Yao 国尧 , Xue 薛 Lei 雷 , Li 李 Jia-Xian 佳鲜 , Wang 王 Shuo 硕 , Du 杜 Hai-Long 海龙 , Zhu 朱 Yi-Ren 毅仁 , Zhou 周 Yue 月
Published: April 2024

The hybrid scenario, which has good confinement and moderate MHD instabilities, is a proposed operation scenario for international thermonuclear experimental reactor (ITER). In this work, the effect of plasma rotation on the HL-3 hybrid scenario is analyzed with the integrated modeling framework OMFIT. The results show that toroidal rotation has no obvious effect on confinement with a high line averaged density of n
bar ∼ 7 × 1019 m−3. In this case, the ion temperature only changes from 4.7 keV to 4.4 keV with the rotation decreasing from 105 rad/s to 103 rad/s, which means that the turbulent heat transport is not dominant. While in the scenarios characterized by lower densities, such as n
bar ∼ 4 × 1019 m−3, turbulent transport becomes dominant in determining heat transport. The ion temperature rises from 3.8 keV to 6.1 keV in the core as the rotation velocity increases from 103 rad/s to 105 rad/s. Despite the ion temperature rising, the rotation velocity does not obviously affect electron temperature or density. Additionally, it is noteworthy that the variation in rotation velocity does not significantly affect the global confinement of plasma in scenarios with low density or with high density.
Tritium management in ITER test blanket systems port cell for maintenance operations
Authors: Jiang Yingwu , Wu Jiewei , Ji Fuhao , Wang Yuqing , Ni Muyi , Jiang Man
Published: April 2024

Four Test Blanket Systems (TBS) will be tested in the International Thermonuclear Experimental Reactor equatorial ports #16 and #18 to verify tritium breeding and heat extraction technology. A significant quantity of tritium would be produced in TBM, and partly released into the port cell from the pipework of TBS or other high-temperature components due to its strong mobility and high permeation. The port cell should be accessible during equipment maintenance and human intervention. This work built a multi-dimensional geometric model to characterize HTO transport in the port cell, absorption/desorption, and diffusion in walls and discussed the effect of paint thickness, ventilation rate, source term, and epoxy properties on detritiation efficiency. The results suggest that a 0.1–0.16 mm paint with the lowest HTO solubility is optimal from the compromise between quick cleanup and tritiated waste decommission. A higher ventilation rate could accelerate detritiation while minimizing the radioactive source by a tritium-resisting layer is the most direct method. The optimized design options for reducing the time required to reach 1 DAC in 12 h still need further discussion because of the delayed HTO source from epoxy paint and dead zone of the flow field.
Tokamak edge localized mode onset prediction with deep neural network and pedestal turbulence
Authors: Joung Semin , Smith David R. , McKee G. , Yan Z. , Gill K. , Zimmerman J. , Geiger B. , Coffee R. , O’Shea F.H. , Jalalvand A. , Kolemen E.
Published: April 2024

A neural network, BES-ELMnet, predicting a quasi-periodic disruptive eruption of the plasma energy and particles known as edge localized mode (ELM) onset is developed with observed pedestal turbulence from the beam emission spectroscopy system in DIII-D. BES-ELMnet has convolutional and fully-connected layers, taking two-dimensional plasma fluctuations with a temporal window of size 128 µs and generating a scalar output which can be interpreted as a probability of the upcoming ELM onset. As approximately labeled inter-ELM broadband (

15

kHz
⩽
f
⩽
150

kHz

) fluctuations are given to the network, BES-ELMnet learns by itself ELM-related precursors arising before the onsets through supervised learning scheme. BES-ELMnet achieves the gradually increasing ELM onset probabilities between two consecutive ELMs during the inter-ELM phases and can forecast the first ELM onsets which occur after the high confinement mode transition. We further investigate the network generality in terms of the selected frequency band to ensure the use of BES-ELMnet for various operation regimes without changing the trained architecture. Therefore, our novel prediction method will enhance a proactive high confinement mode control of fusion-grade plasmas.
Using LQR controller for vertical position control on EAST
Authors: Rui Wangyi , Wang Yuehang , Song Huihui , Luo Zhengping , Huang Yao , Yu Qingze , Liu Zijie , Wu Kai , Xiao Bingjia
Published: April 2024

Vertical position control is essential for stabilizing plasma with elongated configurations. The EAST tokamak is equipped with a set of in-vessel control (IC) coils dedicated to this purpose. Currently, a PD controller with fixed parameters is used for the vertical position control of EAST plasma. However, the response of the plasma in the vertical position changes with changes in plasma configuration, which can result in different control parameter requirements. It is essential to develop a model-based fast-tuning control algorithm for ensuring stability in the vertical position under different configurations. In this study, a model-based vertical position controller tuning method based on a linear quadratic regulator algorithm (LQR) is proposed. Compared with contemporary PD controllers, the proposed model-based LQR controller can enable adjusting controller parameters based on the response of the system, achieving stable control under different vertical position responses. In the EAST experiment, the model-based LQR controller achieved stable control under a shot with a continuously increasing growth rate and reached a maximum controllable vertical displacement growth rate of 968 s−1. The robustness of the system was also demonstrated in a free drift experiment. The new vertical displacement control method can be adapted to different system states and plasma configurations and improve the controllability and safety of future devices.
Measurement of toroidal Alfvén eigenmode-driven fast-ion flows using an imaging neutral particle analyzer at ASDEX Upgrade
Authors: Rueda-Rueda J. , Garcia-Munoz M. , Viezzer E. , Schneider P.A. , Galdon-Quiroga J. , Garcia-Dominguez J. , Oyola P. , Velarde L. , Hidalgo-Salaverri J. , Du X. , Van Zeeland M.A. , Videla-Trevin M. , Gonzalez-Martin J. , Lauber Ph. , Lunt T. , Herrmann A. , Ayllon-Guerola J. ,   the ASDEX Upgrade Team
Published: April 2024

Alfvén Eigenmodes-driven fast-ion flows have been measured for the first time at the ASDEX Upgrade tokamak using an imaging neutral particle analyzer. The flow is such that particles are expelled from the mode location, losing energy as they move outwards. This flow aligns well with the projection of the lines of constant magnetic moment and constant E′ (

E

′

=
E
−
ω

P
ϕ

/

n

, with E being the particle energy,

ω
,
n

the mode frequency and toroidal number and P

φ
the toroidal canonical angular momentum). The observed redistributions are consistent with full-orbit simulations performed with the ASCOT5 code, using the mode structure predicted by the linear gyro-kinetic code LIGKA.
Changes in global carbon use efficiency in the 21st century and the potential controlling factors
Authors: Chen Guo , Chen Tiantian , Peng Li
Published: April 2024

Extensive studies have demonstrated the spatiotemporal changes in carbon use efficiency (CUE) and its driving factors over the past three decades. However, how the global CUE will change and to what extent the CUE is affected by the dominant factor in this century is still unclear. Herein, based on CMIP6 model outputs, we estimated the situation and change trends of CUE in baseline (1982–2014) and future (2015–2100), and identified the controlling factor of CUE variation by boosted regression tree. Further, we predicted the CUE-controlling factor sensitivity (S
value, referring to higher/lower controlling factor producing more/less CUE) and its variation under four representative pathways, and revealed the relationship between S
value and social economy. Results showed decreased CUE at the end of the 21st century, especially in the SSP5-8.5, its decline rate of CUE is 1.2 × 10−2 ± 5.2 × 10−4/decade, which is 10 times higher than that in the SSP1-2.6. Spatially, 56.9%, 74.5%, 83.1%, and 88.6% of the global land will exhibit a decreased CUE under the SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5 scenarios, and primarily concentrates at the middle-high latitudes of the Northern Hemisphere (30°–60° N). Except in Africa, temperature is the controlling factor for CUE variation, and the S
value decreases over time, indicating an enhanced inhibitory effect of temperature on CUE. The turning time of S
value change will advance with increases in CO2 emission, presenting prolonged high-temperature stress of vegetation ecosystem under high-emission scenarios. A threshold effect can be found between S
value change and precipitation, and the precipitation threshold is higher under the SSP5-8.5 scenario. The negative effect of temperature on CUE is attenuated by economic development and population control but this effect diminishes with rising CO2 concentrations; in the future, developing clean energy and formulating population management policies can be used to enhance the carbon sink ability of the global ecosystem.
Earth system responses to carbon dioxide removal as exemplified by ocean alkalinity enhancement: tradeoffs and lags
Authors: Jeltsch-Thömmes Aurich , Tran Giang , Lienert Sebastian , Keller David P , Oschlies Andreas , Joos Fortunat
Published: April 2024

Carbon dioxide removal (CDR) is discussed for offsetting residual greenhouse gas emissions or even reversing climate change. All emissions scenarios of the Intergovernmental Panel on Climate Change that meet the ‘well below 2 °C’ warming target of the Paris Agreement include CDR. Ocean alkalinity enhancement (OAE) may be one possible CDR where the carbon uptake of the ocean is increased by artificial alkalinity addition. Here, we investigate the effect of OAE on modelled carbon reservoirs and fluxes in two observationally-constrained large perturbed parameter ensembles. OAE is assumed to be technically successful and deployed as an additional CDR in the SSP5-3.4 temperature overshoot scenario. Tradeoffs involving feedbacks with atmospheric CO2 result in a low efficiency of an alkalinity-driven atmospheric CO2 reduction of −0.35 [−0.37 to −0.33] mol C per mol alkalinity addition (skill-weighted mean and 68% c.i.). The realized atmospheric CO2 reduction, and correspondingly the efficiency, is more than two times smaller than the direct alkalinity-driven enhancement of ocean uptake. The alkalinity-driven ocean carbon uptake is partly offset by the release of carbon from the land biosphere and a reduced ocean carbon sink in response to lowered atmospheric CO2 under OAE. In a second step we use the Bern3D-LPX model in CO2 peak-decline simulations to address hysteresis and temporal lags of surface air temperature change (ΔSAT) in an idealized scenario where ΔSAT increases to ~2 °C and then declines to ~1.5 °C as result of CDR. ΔSAT lags the decline in CO2-forcing by 18 [14–22] years, depending close to linearly on the equilibrium climate sensitivity of the respective ensemble member. These tradeoffs and lags are an inherent feature of the Earth system response to changes in atmospheric CO2 and will therefore be equally important for other CDR methods.
Assessment of water quality for Al-Salibat marsh\Southern Iraq
Authors: Aqeel Al-Taee Ibtehal , Saad Al-Khafaji Ansam , Hussein Radhi Rasha
Published: April 2024

The objective of the current study is to assess if water is suitable for drinking, irrigation, and aquatic life. From April 2021 to January 2022, water samples were taken on a monthly basis from three locations in the Salibat marsh. To apply the Canadian index, fourteen variables were tracked, including (Water temperature (WT), pH, Turbidity (Tur), Electrical conductivity (EC), Total dissolved solids (TDS), Dissolved Oxygen (DO), Biological oxygen demand (BOD5), Total hardness (TH), Nitrate (NO3), Nitrite (NO2), Active Phosphate (PO4), Cadmium (Cd), Lead (Pb) and Zinc (Zn)). The results showed that the water temperature varied from (20.1 to 39) C°. pH values ranged between (7.1-9.5), Turbidity (9.8-54.78) NTU, total hardness that varied from (120 to 560) CaCO3mg/l. Electrical conductivity was between (2650-23220) μs/cm. Total dissolved solids ranged between (1014-9428) mg/l, dissolved oxygen and biological oxygen demand ranged between (5-9.1) (10-18) mg\l respectively. Nitrate, nitrite and phosphate ranged between (0.14-59.10), (0.16-10.13), (0.04-5.65) μg\l, Cadmium, Zinc and Lead (0-0.022)(0-0.50)(0-0.42) mg\l. Results showed that the water quality was varied from marginal to good for irrigation but poor to marginal for aquatic life. It was also poor to marginal for drinking. Results showed that the water was suitable for irrigation, but not for drinking or aquatic life.
Removal effeciency of blue basic dye41 by using Fe3O4 magnetic nanomaterial.
Authors: Al Nada Hussein Qatar , Imran Amerah , Abdul Kadhim Mohammed
Published: April 2024

The study was conducted in January 2023. The study used nano-iron oxide treatment, iron oxide coated with citric acid, and nano-iron oxide grafted with wheat hulls, in the adsorption of basic blue dye 41 from the medium. Three criteria are used: knowing the best time to remove the dye, the best medium that helps in the adsorption method, and the best concentration of the dye that can be removed the fastest. The results were as follows: The best time: Fe3O4 was (10.50) minutes with a 97% removal rate, NM-AC was 10 minutes with a 94% removal rate, NM-BO was 10 minutes with a 98% removal rate. The best pH for Fe3O4 was at pH 6 with a removal rate of 97%. NM-AC was at pH 6 with a removal rate of 92%. NM-BO was at pH 6 with a removal rate of 97%. The best concentration of Fe3O4 is 10 ppm with a 98% removal rate, NM-AC is 10 ppm with a 98% removal rate, n NM-BO is 30 ppm with a 98% removal rate. A spectrophotometer device was used. We conclude. From the study, the chemical precipitation method was used to produce nanosized iron oxide, nanosized iron oxide coated with citric acid, and nanosized iron oxide grafted with wheat hulls, and the surfaces prepared in this study were used as adsorbent surfaces. Research recommendations: Synthesis of nanoparticles in a green chemical method based on cheap and locally available materials.
Chronic Effects of Mixture Two Pesticides on kidney of Common Carp Fish (Cyprinus carpio L. 1758)
Authors: Yaseen Salih Noor , Mohammed Al-Azawi Ahmed J.
Published: April 2024

Pesticides are man-made chemical compounds, widely used in agriculture to control different types of pests, product crops and prevent diseases which damage them. The excessive and unwarranted use of pesticides at various stages of crop production may pose a great danger to the aquatic environment, especially to fish. In this research, an effort has been made to comparative the effect of herbicide (Goldate), insecticide (Alexander) and mixture of them on common carp (Cyprinus carpio) through chronic toxicity bioassay.

In chronic exposure, Toxicological effects of Goldate and Alxander individual and combine as mixture observed by monitoring hematological parameters on common carp fish. There was prepared 3 concentration groups (1/10, 1/100 and 1/200) for every pesticides (Goldate, Alxander and mixture Goldate + Alxander), exposed to juvenile fish (60-80 gm. in weight) for 6 weeks. During the experimental period the result showed a significant increase in the mean value of blood urea and createnine compared with control. There was not found any histological alterations in kidney tissues, in all groups and all concentrations. All groups were similar to control group which show normal appearance of renal glomerulus, renal collecting tubules and hemopoietic tissue.