bluuebunny/crossref_metadata_2025 huggingface dataset:
Multibubble sonoluminescence in supercooled water
Authors: Lindinger Bernhard , Söhnholz Hendrik , Mettin Robert
Published: May 2024

Cavitation in supercooled water has been induced by the short ultrasound pulses of an ultrasonic horn driven at 20 kHz. The cavitation during the ultrasonic pulses and occasionally the crystallization events thereafter have been imaged by a high-speed camera. The probability of ice crystallization in dependence on the pulse duration and temperature showed a high chance for the water to remain liquid if sufficiently short bursts of moderate acoustic power were applied. This regime has been used for the assessment of sonoluminescence (SL) from the generated cavitation bubbles in the supercooled liquid state. To this end, light emitting events were summed up over a number of ultrasonic pulses by an image intensifier. SL appeared mostly directly under the tip of the ultrasonic horn and sometimes also a few millimeters below the tip. The intensity of SL events showed a slight rise for a decrease in temperature, i.e., for an increase in supercooling. This behavior is in accord with the SL dependence on temperature above the freezing point and might be attributed to a further lowering of vapor pressure. An increase in the bubble collapse peak temperature for increased supercooling is calculated on the basis of spherical bubble model calculations, which supports the findings. The simulations predict further that the peak temperature will fall off again beyond a certain supercooling level.
A moment tensor potential for lattice thermal conductivity calculations of α and β phases of Ga2O3
Authors: Rybin Nikita , Shapeev Alexander
Published: May 2024

Calculations of heat transport in crystalline materials have recently become mainstream, thanks to machine-learned interatomic potentials that allow for significant computational cost reductions while maintaining the accuracy of first-principles calculations. Moment tensor potentials (MTPs) are among the most efficient and accurate models in this regard. In this study, we demonstrate the application of MTP to the calculation of the lattice thermal conductivity of α and β-Ga2O3. Although MTP is commonly employed for lattice thermal conductivity calculations, the advantages of applying the active learning methodology for potential generation are often overlooked. Here, we emphasize its importance and illustrate how it enables the generation of a robust and accurate interatomic potential while maintaining a moderate-sized training dataset.
The lift enhancement mechanism caused by the deformation of the surface of the wide-speed waverider
Authors: Qu Feng , Wang Tianyu , Zhao Qian , Sun Di
Published: May 2024

The optimization method provides an effective approach to enhance the low-speed lift of the vortex lift waveriders by deforming the aerodynamic shape refinedly. However, the vortex lift enhancement mechanism of the optimized configuration is unclear. In this study, the flow evolutions of the original and the optimized configurations are studied by employing the delayed detached-eddy simulation. Results indicate that the convex deformation of the leeward surface plays a dominant role in enhancing the vortex lift by enhancing the low-pressure suction at the upstream breakdown location and delaying the vortex breakdown. For the enhancement of the low-pressure suction, the convex deformation intensifies the streamwise vorticity below the axis of the primary vortex of the leading-edge vortex, in turn enhancing the downwash effect and causing the primary vortex to move downward. This reduces the pressure coefficient induced by the primary vortex on the leeward surface, thus enhancing the vortex lift. In terms of the delay of the vortex breakdown, the convex deformation compresses and accelerates the flow between the spanwise convex and the leading edge. These intensities enhance the washing effect along the spanwise direction on the outward wing and cause the primary vortex to deflect toward the outboard wing. Subsequently, the primary vortex and the shedding vortices generated by the shear layer instability merge, which increase the primary vortex intensity, and enhance the streamwise velocity in the vortex axis. Correspondingly, the primary vortex breakdown is delayed. Ultimately, the increased low-pressure region caused by the delay of the vortex breakdown enhances the vortex lift.
Accurate in situ rock density measurement with cosmic ray muon radiography
Authors: Pang Jie , Li Zhiwei , Dong Shuning , Li Jingtai , Mao Xin , Ding Hao , Wang Hao , Guo Xiaoming , Liu Lei , Zhang Jianming , Feng Xinzhou , Liu Bin , Ouyang Xiaoping , Han Ran
Published: May 2024

Muon radiography, which relies on measuring the absorption and attenuation of muons as they pass through matters, offers a new imaging technique capable of revealing the internal structure of large objects. Recent technological advancement allows for the application or testing of muon radiography in various fields, including mining, civil engineering, security check, etc. This study investigates the factors that influence muon radiography, which is used in density inversion, through simulations and experiments. The materials considered for density inversion include water, standard rock, and iron. Our simulation studies show that the number of events detected and selected has an impact on the reconstruction results, and several factors, such as multiple Coulomb scattering processes, recording time, and spatial resolution, which influence the number of muons, must be taken into account when measuring the rock density. We design and conduct a laboratory scale experiment based on the simulation results. We filter the 220 h of recording signals through time coincidence and straight-line fitting to obtain the selected events. Our results reveal that the statistical error of muons survival ratio in recording time significantly impacts the inversion result and decreases the error can improve accuracy greatly. In the experiment, the deviation between the inversion mean value and the expected value can be reduced to 2.4%–2.9% for iron, 7% for water, and 1.5% for standard rock. This density inversion approach provides insight into future density detection of underground structures.
Radiation of twisted waves from a phased array of loop antennas in a resonant magnetoplasma
Authors: Kudrin Alexander V. , Bazhilova Eva V. , Zaitseva Anna S. , Zaboronkova Tatyana M.
Published: May 2024

A study is made of the radiation from a phased array of circular loop antennas in a resonant magnetoplasma. The loops are assumed to have a finite radius and be located on a circumference in such a manner that their axes are aligned with a static magnetic field superimposed on the plasma. The emphasis is placed on determining the total radiated power of such an array and the partial powers going to different azimuthal field harmonics. For these quantities, rigorous integral representations are obtained using an expansion of the excited field in terms of cylindrical vector eigenfunctions of a magnetized plasma medium. Numerical results are reported for the radiation characteristics of the phased array in the whistler frequency range under conditions of the Earth's ionosphere. It is shown that an appropriately phased array is capable of selectively exciting waves with the desired helicity of the phase front and can be useful as a source of twisted whistler-mode waves in a magnetoplasma.
Characterization of surface electric field in β-FeSi2 by Franz–Keldysh oscillations
Authors: Terai Yoshikazu , Tsukamoto Hiroaki , Yamaguchi Haruki
Published: May 2024

The surface electric field (F) of β-FeSi2 has been investigated by Franz–Keldysh oscillations (FKOs) observed in photoreflectance spectra. The FKO signals were observed in an undoped β-FeSi2 epitaxial layer (3 nm) grown on p+-type β-FeSi2 layers (UP+ structure) by molecular beam epitaxy. The surface electric field obtained from the FKO at 11 K was F = 220 kV/cm. The surface electric field was almost independent of the excitation light power and temperature, showing that the surface electric field was not affected by the surface photovoltage effect. In the dependence of F on the thickness of the undoped layer (d), F was nearly constant at d = 2–56 nm. The result showed that the surface electric field of β-FeSi2 was applied to a thin region (<2 nm) at the surface.
Oscillations of coaxial hydrophobic spherical colloidal particles in a micropolar fluid
Authors: Faltas M. S. , Ashmawy E. A. , Sherief H. H. , Othman Heba A.
Published: May 2024

The microstructured flow field of a micropolar model around a straight chain of multiple hydrophobic spherical particles oscillating rectilinearly along their line of centers is studied under the conditions of low Reynolds numbers. In general, the particles can exhibit variations in both radius and amplitude of oscillations, and they are allowed to be unevenly spaced. The amplitudes are required to be small in comparison with a characteristic length, which can be considered as the radius of the larger particle. The concepts of slip length and spin slip length are introduced to characterize the partial slip and spin slip boundary conditions at the hydrophobic surfaces of the colloidal particles. The differential equations that govern the system are solved through a semi-analytical approach in combination with boundary collocation techniques. The interaction effects between the particles are assessed through the in-phase and out-of-phase drag force coefficients acting on each particle for various values of geometrical and physical parameters. The numerical schemes are carried for the case of two oscillating spherical particles. The results of this investigation indicate that the drag coefficients are notably influenced by the presence of the second particle, micropolarity, frequency, and slip parameters. The current study reveals that the impact of the micropolarity parameter is not significant on the in-phase force coefficient for slippage parameter values less than one. However, it becomes significant for slippage parameter values exceeding one. Typically, when particles oscillate in opposing modes, in-phase coefficient values surpass 1, whereas they fall below 1 when oscillating in the same mode. The present study is driven by the necessity to gain a deeper comprehension of the fluid tapping mode employed in atomic force microscope devices, especially when this mode pertains to microstructures in the vicinity of a curved surface.
Numerical study on the dynamic behaviors of shear-thinning droplets impacting on a hydrophobic spherical surface
Authors: Cai Jialiang , Ma Jiliang , Chen Xiaoping , Liu Daoyin , Liang Cai , Pan Suyang
Published: May 2024

In this study, the dynamic behavior of shear-thinning droplets impacting on a hydrophobic spherical surface is numerically investigated using the volume of fluid method coupled with dynamic contact angle and a power-law model. The differences in dynamic behaviors between shear-thinning and Newtonian droplets are first studied. By analyzing the distribution of pressure and shear rate inside the droplet, it is found that the shear-thinning behavior of the droplets leads to an uneven distribution of apparent viscosity upon impact, which in turn prevents droplet rebound. The effects of various impacting conditions, such as apparent viscosity, impact velocity, surface tension and dynamic contact angle, on the spreading factor and liquid film thickness of shear-thinning droplets are investigated. According to the behaviors of droplets, the impacting process can be divided into three phases: (I) initial deformation, (II) inertia-dominated, and (III) viscosity-dominated phases. In order to reveal the physical mechanisms that prevent shear-thinning droplets from rebounding on the hydrophobic particle surface, the conversion of kinetic energy, viscous dissipation, surface energy, and potential energy during the three phases of the impact process is also analyzed in detail.
Flow pulsation characteristics of variable displacement piston pump considering coupling effects cavitation bubble and swash plate inclination angle vibration
Authors: Pan Yang , Zhang Da , Wang Zi Neng , Zou Xi , Yuan Hao
Published: May 2024

Variable-displacement piston pumps, in comparison with quantitative pumps, offer high volumetric efficiency, energy savings, and variable displacement advantages. The outlet flow pulsation of these pumps is influenced by several factors, including swash plate inclination angle vibration, cavitation bubbles, flow distribution structure, and valve control structure. This complexity poses challenges in accurately predicting the flow pulsation at the outlet of variable-displacement piston pumps. In response to this challenge, a novel outlet flow pulsation model for variable-displacement piston pumps is proposed, taking into account the coupling effects of cavitation bubbles and swash plate inclination angle vibration, building upon an existing model. Initially, the effects of cavitation bubbles and swash plate inclination vibrations on flow pulsation were analyzed. Subsequently, a comprehensive flow pulsation model for variable-displacement piston pumps was developed, considering the coupling effects of cavitation bubbles and swash plate inclination angle vibrations. This model was compared with three other existing flow pulsation models. The accuracy of the results was validated using a constructed test bench, with an accuracy improvement of approximately 12% compared to traditional theoretical models. Finally, an optimization model for outlet flow pulsation was proposed. The structural parameters of the valve plate, aimed at minimizing flow pulsation, were determined using the multi-agent particle swarm optimization algorithm. These findings underscore the importance of considering the coupled effects of cavitation bubble and swash plate inclination angle vibration in the design optimization process for reducing low-flow pulsation. This study provides a theoretical foundation for the design of variable-displacement piston pumps with minimized vibration and noise levels.
Preictal dysfunctions of inhibitory interneurons paradoxically lead to their rebound hyperactivity and to low-voltage-fast onset seizures in Dravet syndrome
Authors: Capitano Fabrizio , Kuchenbuch Mathieu , Lavigne Jennifer , Chaptoukaev Hava , Zuluaga Maria A. , Lorenzi Marco , Nabbout Rima , Mantegazza Massimo
Published: May 2024

Epilepsies have numerous specific mechanisms. The understanding of neural dynamics leading to seizures is important for disclosing pathological mechanisms and developing therapeutic approaches. We investigated electrographic activities and neural dynamics leading to convulsive seizures in patients and mouse models of Dravet syndrome (DS), a developmental and epileptic encephalopathy in which hypoexcitability of GABAergic neurons is considered to be the main dysfunction. We analyzed EEGs from DS patients carrying a
SCN1A
pathogenic variant, as well as epidural electrocorticograms, hippocampal local field potentials, and hippocampal single-unit neuronal activities in
Scn1a
+/−
and
Scn1a
RH/+
DS mice. Strikingly, most seizures had low-voltage-fast onset in both patients and mice, which is thought to be generated by hyperactivity of GABAergic interneurons, the opposite of the main pathological mechanism of DS. Analyzing single-unit recordings, we observed that temporal disorganization of the firing of putative interneurons in the period immediately before the seizure (preictal) precedes the increase of their activity at seizure onset, together with the entire neuronal network. Moreover, we found early signatures of the preictal period in the spectral features of hippocampal and cortical field potential of
Scn1a
mice and of patients’ EEG, which are consistent with the dysfunctions that we observed in single neurons and that allowed seizure prediction. Therefore, the perturbed preictal activity of interneurons leads to their hyperactivity at the onset of generalized seizures, which have low-voltage-fast features that are similar to those observed in other epilepsies and are triggered by hyperactivity of GABAergic neurons. Preictal spectral features may be used as predictive seizure biomarkers.
Impact of energy–momentum conservation violation on the configuration of compact stars and their GW echoes
Authors: Bora Jyatsnasree , Jyoti Gogoi Dhruba , Maurya S K , Mustafa Ghulam
Published: May 2024

This work investigates the impacts of energy–momentum conservation violation on the configuration of strange stars constraint with gravitational wave (GW) event GW190814 as well as eight recent observations of compact objects. The GW echoes from these interesting classes of compact objects are also calculated. To describe the matter of strange stars, we have used two different equations of state (EoSs): first an ad-hoc exotic EoS, the stiffer MIT Bag model and next realistic CFL phase of quark matter EoS. We choose Rastall gravity as a simple model with energy–momentum conservation violation with a set of model parameter values. Our results show that this gravity theory permits stable solutions of strange stars and the resulting structures can foster GW echoes. We illustrate the implication of the gravity theory and found that the negative values of the Rastall parameter result in more compact stellar configurations and lower GW echo frequency. With an increase in the Rastall parameter, both the compactness of the stellar configurations and echo time decrease. It is worth mentioning here that with the chosen set of some probable strange star candidates from observational data and also in light of GW 190814, we have evaluated the radii of stellar models. Also, the GW echo frequencies associated with strange stars are found to be in the range of

≈

9–27 kHz for both cases. From this work, it is also inferred that the assumption regarding the equivalence of Rastall’s theory to Einstein’s theory is refuted as we have noticed many deviations in the physical properties of the considered compact stars.
Cosmological higher-curvature gravities
Authors: Moreno Javier , Murcia Ángel J
Published: May 2024

We examine higher-curvature gravities whose Friedmann–Lemaître–Robertson–Walker configurations are specified by equations of motion which are of second order in derivatives, just like in Einstein gravity. We name these theoriesCosmological Gravitiesand initiate a systematic exploration in dimensionsD⩾3. First, we derive an instance of Cosmological Gravity to all curvature orders and dimensionsD⩾3. Second, we study Cosmological Gravities admitting non-hairy generalizations of the Schwarzschild solution characterized by a single function whose equation of motion is, at most, of second order in derivatives. We present explicit instances of such theories for all curvature orders and dimensionsD⩾4. Finally, we investigate the equations of motion for cosmological perturbations in the context of generic Cosmological Gravities. Remarkably, we find that the linearized equations of motion for scalar cosmological perturbations in any Cosmological Gravity inD⩾3contain no more than two time derivatives. We explicitly corroborate this aspect by presenting the equations for the scalar perturbations in some four-dimensional Cosmological Gravities up to fifth order in the curvature.
Prediction of the 1st excitation energy of odd–odd nuclei with the Bayesian neural network approach
Authors: Gao T J , Wang H D , Lu Jing-Bin , Lu Yi , Yang Pei-Yao , Qin M J
Published: May 2024

A Bayesian neural network (BNN) is developed to predict the 1st excitation energy of odd–odd nuclei. Aside from the proton number and neutron number, we introduce two empirical physical quantities into the input layer.

δ
=
[

−
1

N

+

−
1

Z

]

/

2

is introduced to distinguish even–even, odd–odd and odd-A nuclei; and the so-called Casten factor

P
≡

v

p

v

n

v

p

+

v

n

is introduced to stand for collectivity. The BNN is trained with an experimental dataset of the 1st excitation energy for 434 odd–odd, 649 even–even and 1050 odd-A nuclei. After training, the BNN predicts the 1st excitation energy of odd–odd nuclei with a rms of 0.21 MeV. Examples of Dy, Gd, Eu and Cs isotopes are also shown. The BNN results show moderate predictive ability, in comparison with results from the projected Hartree–Fock method.
Accuracy calibration of the multi-light screen measurement system using array optical signal
Authors: Chen Ding , Deng Chenghua , Yang Ziyu , Shen Lingnan , Han Jinxi
Published: May 2024

The multi-light screen measurement systems must be calibrated before being come into use, and a calibration method using live-fire practice is generally adopted. However, this method has many shortcomings, such as high cost, high risk and poor efficiency. To effectively improve the measurement accuracy of a multi-light screen measurement system, we propose a calibration method based on array optical signal in the paper. According to the measurement principle of the system, the proposed calibration theory is systematically described. The aim is to map the given measurement results in the form of vector into the specified time sequence. Furthermore, we develop a calibration platform whose core components are an arbitrary waveform generator and a tunable laser, and thus it can generate a set of six optical signals with an exact sequential relationship. After receiving the optical signals, some measurement results with errors are obtained by the system. Many calibration operations are performed to obtain the systematic errors, which are the statistical average of the deviation between the given measurement results and those with errors. Finally, we use the proposed calibration method combined with the error tensor and the traditional one to carry out comparison experiments. The results show that the proposed calibration method is superior to the traditional method in terms of comprehensive performance. In addition, the proposed calibration method relative to the traditional ones has some advantages, such as high efficiency, safety and low cost.
A novel robotic-assisted deep learning-enabled computer vision approach for nondestructive diagnosis of railway bolt faults
Authors: Hua Jiang , Wang Zhen , Han Hao , Gao Haolin , Nie Liangyi
Published: May 2024

Railways play a vital role in the inland transportation system worldwide, and abnormal bolt components at the track joints are the main cause of train accidents. The detection and identification of faults in rail bolt components are of considerable research importance. To address this problem, numerous researchers have opted for computer vision-based methods to accomplish the detection and identification of the target, but the existing methods have poor detection performance diminished detection capabilities when the target position changes or some feature information is occluded, and the detection speed and accuracy are far from meeting the requirements of practical applications. Therefore, based on the construction of a dedicated dataset for bolt components, this paper uses the K-means dimensional clustering algorithm to re-cluster the dataset according to the target size characteristics, with the aim of reduce the bounding box regression error. At the same time, a novel loss function iteration method is proposed by incorporating an adaptive optimization algorithm, in order to improve the detection speed and ensure good convergence, and the model complexity is reduced based on deep model pruning. Finally, the optimized detection model is implemented on the robotic-assisted platform for testing, and the experimental results verify that the algorithm can quickly and accurately complete various fault diagnosis tasks of bolt components in practical applications. The main achievements of this study include the construction of a large-scale image dataset for novel rail bolt components and propelled the application of deep learning methods in vision-based rail bolt fault diagnosis.
Strategies to improve the ionic conductivity of quasi-solid-state electrolytes based on metal-organic frameworks
Authors: Chen Chuan , Luo Xiangyi
Published: May 2024

The low ionic conductivity of quasi-solid-state electrolytes (QSSEs) at ambient temperature is a barrier to the development of solid-state batteries (SSBs). Conversely, metal-organic frameworks (MOFs) with porous structure and metal sites show great potential for the fabrication of QSSEs. Numerous studies have proven that the structure and functional groups of MOFs could significantly impact the ionic conductivity of QSSEs based on MOFs (MOFs-QSSEs). This review introduces the transport mechanism of lithium ions in various MOFs-QSSEs, and then analyses how to construct an effective and consistent lithium ions pathway from the perspective of MOFs modification. It is shown that the ion conductivity could be enhanced by modifying the morphology and functional groups, as well as applying amorphous MOFs. Lastly, some issues and future perspectives for MOFs-QSSEs are examined. The primary objective of this review is to enhance the comprehension of the mechanisms and performance optimization methods of MOFs-QSSEs. Consequently, this would guide the design and synthesis of QSSEs with high ionic conductivity, and ultimately enhance the performance of commercial SSBs.
The evolution problem associated with the fractional first eigenvalue
Authors: Barrios Begoña , Del Pezzo Leandro , Quaas Alexander , Rossi Julio D
Published: May 2024

In this paper we study the evolution problem associated with the first fractional eigenvalue. We prove that the Dirichlet problem with homogeneous boundary condition is well posed for this operator in the framework of viscosity solutions (the problem has existence and uniqueness of a solution and a comparison principle holds). In addition, we show that solutions decay to zero exponentially fast as

t
→
∞

with a bound that is given by the first eigenvalue for this problem that we also study.
Cerenkov free micro-dosimetry in small-field radiation therapy technique
Authors: Debnath Sree Bash Chandra , Tonneau Didier , Fauquet Carole , Tallet Agnes , Darréon Julien
Published: May 2024

Objective. Optical fiber-based scintillating dosimetry is a recent promising technique owing to the miniature size dosimeter and quality measurement in modern radiation therapy treatment. Despite several advantages, the major issue of using scintillating dosimeters is the Cerenkov effect and predominantly requires extra measurement corrections. Therefore, this work highlighted a novel micro-dosimetry technique to ensure Cerenkov-free measurement in radiation therapy treatment protocol by investigating several dosimetric characteristics. Approach. A micro-dosimetry technique was proposed with the performance evaluation of a novel infrared inorganic scintillator detector (IR-ISD). The detector essentially consists of a micro-scintillating head based on IR-emitting micro-clusters with a sensitive volume of 1.5 × 10−6 mm3. The proposed system was evaluated under the 6 MV LINAC beam used in patient treatment. Overall measurements were performed using IBATM water tank phantoms by following TRS-398 protocol for radiotherapy. Cerenkov measurements were performed for different small fields from 0.5 × 0.5 cm2 to 10 × 10 cm2 under LINAC. In addition, several dosimetric parameters such as percentage depth dose (PDD), high lateral resolution beam profiling, dose linearity, dose rate linearity, repeatability, reproducibility, and field output factor were investigated to realize the performance of the novel detector. Main results. This study highlighted a complete removal of the Cerenkov effect using a point-like miniature detector, especially for small field radiation therapy treatment. Measurements demonstrated that IR-ISD has acceptable behavior with dose rate variability (maximum standard deviation ∼0.18%) for the dose rate of 20–1000 cGy s−1. An entire linear response (R
2 = 1) was obtained for the dose delivered within the range of 4–1000 cGy, using a selected field size of 1 × 1 cm2. Perfect repeatability (max 0.06% variation from average) with day-to-day reproducibility (0.10% average variation) was observed. PDD profiles obtained in the water tank present almost identical behavior to the reference dosimeter with a build-up maximum depth dose at 1.5 cm. The small field of 0.5 × 0.5 cm2 profiles have been characterized with a high lateral resolution of 100 µm. Significance. Unlike recent plastic scintillation detector systems, the proposed micro-dosimetry system in this study requires no Cerenkov corrections and showed efficient performance for several dosimetric parameters. Therefore, it is expected that considering the detector correction factors, the IR-ISD system can be a suitable dose measurement tool, such as in small-field dose measurements, high and low gradient dose verification, and, by extension, in microbeam radiation and FLASH radiation therapy.
Exploring the biological basis of CT imaging features in pancreatic neuroendocrine tumors: a two-center study
Authors: Xu Lei , Wu Yan , Shen Xiaoyong , Zhou Luping , Lu Yongkai , Teng Ze , Du Jichen , Ding Mingchao , Han Hongbin , Niu Tianye
Published: May 2024

Objective. Medical imaging offered a non-invasive window to visualize tumors, with radiomics transforming these images into quantitative data for tumor phenotyping. However, the intricate web linking imaging features, clinical endpoints, and tumor biology was mostly uncharted. This study aimed to unravel the connections between CT imaging features and clinical characteristics, including tumor histopathological grading, clinical stage, and endocrine symptoms, alongside immunohistochemical markers of tumor cell growth, such as the Ki-67 index and nuclear mitosis rate. Approach. We conducted a retrospective analysis of data from 137 patients with pancreatic neuroendocrine tumors who had undergone contrast-enhanced CT scans across two institutions. Our study focused on three clinical factors: pathological grade, clinical stage, and endocrine symptom status, in addition to two immunohistochemical markers: the Ki-67 index and the rate of nuclear mitosis. We computed both predefined (2D and 3D) and learning-based features (via sparse autoencoder, or SAE) from the scans. To unearth the relationships between imaging features, clinical factors, and immunohistochemical markers, we employed the Spearman rank correlation along with the Benjamini-Hochberg method. Furthermore, we developed and validated radiomics signatures to foresee these clinical factors. Main results. The 3D imaging features showed the strongest relationships with clinical factors and immunohistochemical markers. For the association with pathological grade, the mean absolute value of the correlation coefficient (CC) of 2D, SAE, and 3D features was 0.3318 ± 0.1196, 0.2149 ± 0.0361, and 0.4189 ± 0.0882, respectively. While for the association with Ki-67 index and rate of nuclear mitosis, the 3D features also showed higher correlations, with CC as 0.4053 ± 0.0786 and 0.4061 ± 0.0806. In addition, the 3D feature-based signatures showed optimal performance in clinical factor prediction. Significance. We found relationships between imaging features, clinical factors, and immunohistochemical markers. The 3D features showed higher relationships with clinical factors and immunohistochemical markers.
Design of an ultra-wideband and switchable VO2-based microwave absorber
Authors: Nguyen Thi Quynh Hoa , Phan Huu Lam , Lam Vu Dinh , Kim Jung-Mu
Published: May 2024

We propose a design of an ultra-wideband microwave metamaterial absorber using Vanadium dioxide (VO2) based on a dual-layer structure. The ultra-wideband absorption performance of the proposed structure can switch by using the phase transition of VO2. When the VO2 is in the insulator state, the proposed absorber achieves an ultra-wideband absorption response in the range of 3.7–22.5 GHz with an absorptivity higher than 0.9 and a relative bandwidth of 143.5% at normal incidence, which covers the entire bands from the C to Ku. The designed absorber is polarization insensitive and wide incident angle stable for both transverse electric (TE) and transverse magnetic (TM) modes. Owing to the outstanding merits of absorption performance and frequency-tunable capability, our design structure can be suitable for many promising applications in the microwave range, such as smart radar, camouflage and stealth radome technology.
Orthorhombic metal carbide-borides MeC2B12 (Me = Mg, Ca, Sr) from first principles: structure, stability and mechanical properties
Authors: Bystrenko Oleksiy , Zhang Jingxian , Sun Tianxing , Ruan Hu , Duan Yusen , Zhang Kaiqing , Li Xiaoguang
Published: May 2024

First principle DFT simulations are employed to study structural and mechanical properties of orthorhombic B12-based metal carbide-borides. The simulations predict the existence of Ca- and Sr- based phases with the structure similar to that of experimentally observed earlier compound MgC2B12. Dynamical stability of both phases is demonstrated, and the phase CaC2B12 is found to be thermodynamically stable. According to simulations, Ca- and Sr- based phases have significantly enhanced mechanical characteristics, which suggest their potential application as superhard materials. Calculated shear and Young’s moduli of these phases are nearly 250 and 540 GPa, respectively, and estimated Vickers hardness is 45–55 GPa.
Exploring the electronic, optical, and thermoelectric features of BaXCu3Se4 (X = In, Tl) quaternary chalcogenides: first-principles study
Authors: Mohamed Abdelhay Salah , Gul Banat , Salman Khan Muhammad , Benabdellah Ghlamallah , Ahmad Bashir , Ahmad Hijaz
Published: May 2024

The tunable optical characteristics and superior thermal stability of Indium and Thallium-based quaternary chalcogenides are significant. We studied the intricate relationship between the optoelectronic, and thermoelectric features of notable BaXCu3Se4 (X = In, Tl) quaternary chalcogenides. Both the maximum of the valence band and conduction band coincide at the Γ-point, confirming these materials as direct band gap materials. By substituting Indium for thallium, the calculated band gap decreases from 0.71 eV to 0.53 eV. These anions have a considerable impact and contribute to a decrease in the energy gap via valence electrons. Partially filled d orbitals of copper play an important role in electronic states at the Fermi level. The components of the complex dielectric function, as well as other important optical parameters, are examined and analyzed for the potential usage in optoelectronic devices. The ε
1(ω) becomes negative at 6.32 eV, suggesting that the medium is reflecting all of the incident light. Thallium affects the absorption spectrum because it changes the density of states and electronic transitions. The absorption spectra indicated that the material absorbs in the visible and near-ultraviolet parts of the spectrum, which is fascinating and might have applications in optoelectronics. The investigated materials are appropriate to be used for thermoelectric devices confirmed by their significant and notable thermoelectric properties. Because the Seebeck coefficient is negative, most charge carriers, typically electrons, flow from the higher temperature area to the lower temperature region. At both low and high temperatures, thallium is accountable for BaTlCu3Se4’s higher thermal conductivity than BaInCu3Se4 material.
Kinks and soliton solutions to the coupled Burgers equation by Lie symmetry approach
Authors: Tanwar Dig Vijay , Kumar Raj
Published: May 2024

The current research employs a novel class of invariant solutions to Painlevé integrable coupled Burgers equations. Many mathematical physics domains such as fluid dynamics, traffic flow, nonlinear acoustics, turbulence phenomena, and the interaction of convection and diffusion processes, use this fundamental model. The presented investigations utilize the Lie point symmetry to yield a class of exact solutions unknown in previous findings. Lie point symmetry reduces the number of independent variables in coupled Burgers equations. For the physical visualizations of the solutions, their profiles are analysed. Since arbitrary functions and constants are available in the solutions, the derived solutions have the potential to reveal rich physical structures. We next go over kink waves, multisoliton, line multisoliton and annihilation profiles in detail. We compute conserved vectors to demonstrate the integrability of CBEs. The results demonstrate their novelty, as they diverge completely from previous findings.
Unifying ordinary and null memory
Authors: Heisenberg Lavinia , Xu Guangzi , Zosso Jann
Published: May 2024

Based on a recently proposed reinterpretation of gravitational wave memory that builds up on the definition of gravitational waves pioneered by Isaacson, we provide a unifying framework to derive both ordinary and null memory from a single well-defined equation at leading order in the asymptotic expansion. This allows us to formulate a memory equation that is valid for any unbound asymptotic energy-flux that preserves local Lorentz invariance. Using Horndeski gravity as a concrete example metric theory with an additional potentially massive scalar degree of freedom in the gravitational sector, the general memory formula is put into practice by presenting the first account of the memory correction sourced by the emission of massive field waves. Throughout the work, physical degrees of freedom are identified by constructing manifestly gauge invariant perturbation variables within an SVT decomposition on top of the asymptotic Minkowski background, which will in particular prove useful in future studies of gravitational wave memory within vector tensor theories.
Marine carbon dioxide removal by alkalinization should no longer be overlooked
Authors: Kowalczyk Katarzyna A , Amann Thorben , Strefler Jessica , Vorrath Maria-Elena , Hartmann Jens , De Marco Serena , Renforth Phil , Foteinis Spyros , Kriegler Elmar
Published: May 2024

To achieve the Paris climate target, deep emissions reductions have to be complemented with carbon dioxide removal (CDR). However, a portfolio of CDR options is necessary to reduce risks and potential negative side effects. Despite a large theoretical potential, ocean-based CDR such as ocean alkalinity enhancement (OAE) has been omitted in climate change mitigation scenarios so far. In this study, we provide a techno-economic assessment of large-scale OAE using hydrated lime (‘ocean liming’). We address key uncertainties that determine the overall cost of ocean liming (OL) such as the CO2 uptake efficiency per unit of material, distribution strategies avoiding carbonate precipitation which would compromise efficiency, and technology availability (e.g., solar calciners). We find that at economic costs of 130–295 $/tCO2 net-removed, ocean liming could be a competitive CDR option which could make a significant contribution towards the Paris climate target. As the techno-economic assessment identified no showstoppers, we argue for more research on ecosystem impacts, governance, monitoring, reporting, and verification, and technology development and assessment to determine whether ocean liming and other OAE should be considered as part of a broader CDR portfolio.
Integration of Green and Blue Space, and Their Potential to Support The Mental Health of Tropical Urban Residents
Authors: Defiana I , Salsabila N
Published: May 2024

Problems in metropolis cities such as rising air temperature, traffic density often cause discomfort. It will result in heat stress and impact on mental health. Integration of blue space and green space is needed to reduce these risks. Urban parks, natural or artificial lakes are examples of integration. This paper describes opportunities for integrating blue spaces and green nature urban parks that have the potential to support mental health of tropical urban residents. Method used in this research is observation. Pondok Jagung lake-Tangerang used as a case study. The study was conducted in context of biophilic design. Results of study indicate that the integration of blue space and green space in urban parks has potential to support mental health for residents. Aspects that are considered are design aspects and environmental aspects. Design aspects include proportion of blue and green space, arrangement of colored vegetation, natural or non-natural shading, lighting, activity with water, accessibility, safety, security. Environmental aspects are cleanliness, order of hawkers. All aspect affects multi-sensory such as thermal comfort, visual, audio, olfactory, tactile.
The resilience level of Kampung Sekretaris as urban village in response to urban development in the surrounding area
Authors: Astuti M C M P , Luru M N , Ramadhani A
Published: May 2024

Kampung Sekretaris is an urban village in a rapidly developing urban area. This urban development has transformed the area around Kampung Sekretaris into a commercial zone. Its central location surrounded by commercial area could potentially threaten the existence of the urban village due to its strategic significance. Like many settlements, this urban village faces common issues such as flooding, slums, and inadequate sanitation. Given these challenges, one might expect Kampung Sekretaris to struggle for survival. However, remarkably, Kampung Sekretaris not only persists but also features in the government’s planning program. The aim of this study is to assess the level of resilience displayed by Kampung Sekretaris in response to urban development. The research method employed is quantitative descriptive analysis. Analytical techniques include scoring, which involves the use of Resilience Radar Index indicators, and quantitative descriptive analysis to evaluate Kampung Sekretaris’s resilience to urban development over time. The results indicate that Kampung Sekretaris exhibits a very high level of resilience. The following factors explain the relationship between this result and urban development: (1) Community capacity affects building functions; (2) Social capital influences land use; (3) The interconnectedness is evident through the kampung’s land use as a residential area; (4) The restoration of Kali Sekretaris river serves as disaster preparedness, with no more buildings along its banks; (5) A network of interconnected roads supports disaster evacuation; (6) Arterial roads facilitate the growth of trade; and (7) Changes in the functions of buildings reflect the community’s adaptability in seeking livelihood sources.
Thermal-structural Modeling of power electronic package: effects of deposition geometry and dry spot on the stress distributions
Authors: Mirone Giuseppe , Barbagallo Raffaele , Bua Giuseppe , Sitta Alessandro , Calabretta Michele , Sequenzia Gaetano
Published: May 2024

A Power Electronics package is a heterogeneous system made of semiconductor devices (dies), metallic-ceramic substrate, baseplate and encapsulating material.

The electronic devices can be MOSFETs (Metal Oxide Semiconductors Field Effect Transistors), diodes, IGBTs (Insulated Gate Bipolar Transistors) and passive components such as capacitors, resistors and sensors integrated on support circuit; the complete set of semiconductor devices installed on a package form the so-called “power modulus”.

These devices play an important role in the transmission and conversion of energy in electric and hybrid vehicles. Due to the elevated currents and, consequently, the elevated temperatures at which these systems work, and due to the mismatch of the thermal-mechanical properties of the materials from which they are made, stresses and strains develop within the devices.

Such stresses can be locally concentrated and amplified, depending on the deposition geometry of the various layers constituting the semiconductor device. Edge termination structures are essential to decrease the electric field at die’s edges, and, including brittle compounds in their composition, like Si3N4 or SiO, they are quite sensitive to mechanical stress.

Another reason that may cause the stresses concentrations is the presence of dry spots. Dry spots are areas of various size, located at the interface between die or leadframe and the encapsulating resin, where there is a total or partial lack of adhesion.

The aims of this work are, mainly, two. At first, four linear finite element analyses have been performed in order to evaluate the stresses concentrations at the corners of edge termination structure.

The first case concerns sharp corners and the other cases concern differently filleted corners. In the second part of this work, it has been analysed the dry spot effect on stress distributions. Due to the small size of the defect with respect to the whole package, a Global-Local FEM approach has been used, creating a local subdomain where the mesh is denser than the global domain and a running a further separate numerical analysis which takes its boundary conditions from the global analysis, so delivering reliable small-scale stress and strain gradients. This approach permits to achieve accurate analyses focused on zones of interest of the global domain, limiting the increase of the computational cost of the modelling.
Multimethodology based on Design-to-Value (DtV), integrated with simulation techniques and prioritization of teamwork for the optimization of a pneumatic rack & pinion actuator
Authors: Maiocchi G , Vigliano L , Nicoletto G
Published: May 2024

The investigations here presented focus on the redesign and innovation of a pneumatic rack and pinion actuator for valve actuation, as a case study for investigating the potential of a multimethodology based on the Design to Value (DtoV) process, coupled with design techniques utilizing FEA simulations and giving high priority to teamwork. The final objective of this case study is to show how it is possible to optimize the design, increasing weight efficiency while maintaining performance, and to simplify it, with a reduction of components construction complexity, according to the growing demand for a lean production. The principle that guided all the activities was valorizing the power of teamwork, focusing the team on Safety and Reliability. In an initial phase, all the instruments foreseen by “Design-to-Value” process have been applied, obtaining a classification of the contents of the product constituting its sources of value. Subsequent outputs are proposals for efficient construction solutions, driving a second phase, dedicated to the re-design of the actuator. The peculiarity of this project has been to combine the “Design by Formulas” techniques with advanced FEA simulations (“Design by Analysis”), aiming to stress, deformation, and topology optimization. A two-step experimental validation is used, based on a preliminary “mockup” prototype followed by a complete detailed prototype, for confirming the results of the calculations and simulations, by directly performing a series of in-depth tests. Preliminary obtained results show that the approach based on the described multimethodology, makes it possible to optimize the design of the actuator, maintaining safety, reliability, and performance. In the case studied, the weight reduction is expected to be 8% and economic efficiency increase is expected to be near 20%.
FMEA, monitoring, retrofit and redesign of insulated rail joints
Authors: Bracciali A , Megna G
Published: May 2024

Insulated rail joints (IRJ) are a fundamental component of railway signalling that ensure train protection using “track circuits”. A track circuit is a section of line delimited by rail joints electrically insulated, powered at one end with an electric power supply to establish a different voltage that is checked at the other end with a so-called “track circuit relay”. When the section is short-circuited by an axle the relay drops, and the section is defined as “occupied”. IRJ are subjected to continuous and dangerous failures as they represent a singularity in the rail continuity. Continuous battering produces the classical train impact noise while damage in the rail accumulates until the IRJ fails with extremely unpleasant consequences. The paper discusses the main failure modes of an IRJ starting from a historical perspective, showing how an appropriate failure analysis would have prevented a catastrophic accident that recently occurred in Italy. Several countermeasures are shown and a completely new IRJ potentially completely solving the issue is introduced.