bluuebunny/crossref_metadata_2025 huggingface dataset:
High angular momentum coupling for enhanced Rydberg-atom sensing in the very-high frequency band
Authors: Prajapati Nikunjkumar , Kunzler Jakob W. , Artusio-Glimpse Alexandra B. , Rotunno Andrew P. , Berweger Samuel , Simons Matthew T. , Holloway Christopher L. , Gardner Chad M. , Mcbeth Michael S. , Younts Robert A.
Published: February 2024

Recent advances in Rydberg-atom electrometry detail promising applications in radio frequency communications. Presently, most applications use carrier frequencies greater than 1 GHz where resonant Autler–Townes splitting provides the highest sensitivity. This letter documents a series of experiments with Rydberg atomic sensors to collect and process waveforms from the automated identification system (AIS) used in maritime navigation in the very high frequency (VHF) band. Detection in this band is difficult with conventional resonant Autler–Townes based Rydberg sensing and requires a new approach. We show the results of a method called high angular momentum matching excited Raman (HAMMER), which enhances low frequency detection and exhibits superior sensitivity compared to the traditional AC Stark effect. From measurements of electromagnetically induced transparency in rubidium and cesium vapor cells, we show the relationship between incident electric field strength and observed signal-to-noise ratio and find that the sensitivity of the HAMMER scheme in rubidium achieved an equivalent single VHF tone sensitivity of 100μV/m/Hz. With these results, we estimate the usable range of the atomic vapor cell antenna for AIS waveforms given current technology and detection techniques.
A numerical study on dynamic flows past three tandem inclined elliptic cylinders near moving wall
Authors: Duong Viet Dung , Nguyen Van Luc , Nguyen Van Tien , Palar Pramudita Satria , Zuhal Lavi Rizki , Ngo Trung Thuc , Dinh Cong-Truong , Wang Wei-Cheng
Published: February 2024

This numerical study focuses on the dynamic flows past three tandem inclined elliptic cylinders of equal spacing parallel to a moving wall using a lattice Boltzmann method. The gap ratio (G/D=0.6–2.5, where G and D are the gap between the wall surface and cylinder center and major axis, respectively), spacing ratio (L/D=1.5–10, where L is the distance of two adjacent cylinder centers), and inclination angle (α=±15°,±30°,±45°—the angle between normal vector and cylinder's major-axis) are explored at Reynolds number Re = 150 (based on D). The intended analysis links hydrodynamic coefficients, wake structures, and spectral analysis in parameter space of α−G/D−L/D to fluid mechanics. The flow is highly adjustable in this space, dividing into seven regimes: overshoot, continuous reattachment, alternative reattachment, wavy, meandering, quasi-coshedding, and coshedding, which are spatially classified into four modes due to flow interference: shear layer, primary, two-layered, and secondary vortex shedding modes. Transitions between adjacent modes determine three boundaries; and hydrodynamic coefficients differ substantially in parameter space. Due to shadowing, the upstream cylinder has a larger drag coefficient than the middle and downstream cylinders, reducing the drag coefficient of upstream cylinder and the lift coefficient of middle and downstream cylinders. α=±45° has the highest lift oscillation among the three cylinders and a small drag coefficient of the upstream cylinder. The moving wall's proximity effect increases the upstream cylinder's lift coefficient for α<0°, being negligible for high G/D across the full L/D range and stabilizing the lift oscillation of three cylinders.
Graded in-plane Miura origami as crawling robots and grippers
Authors: Fang Qian-Yi , Xu Shao-Feng , Chu Ming-Shuai , Yan Ting , Xu Zhu-Long , Wu Tian-Yue , Wang Dan-Feng , Tachi Tomohiro , Chuang Kuo-Chih
Published: February 2024

In this work, we propose a variation of Miura origami which, different from the existing out-of-plane bending Miura origami, has an in-plane bent configuration due to its graded crease pattern. By combining with the one-way shape memory alloy spring, we show that the proposed graded Miura origami can serve as a smart actuator and can be applied to drive crawling robots or grippers. First, we constructed a physical model of the graded Miura origami, from which a curvature-programmable geometric equation is proposed. Then, in addition to providing a mechanical model that can capture the mechanical behavior of the initial force–displacement relationship of the curved beam, we show that the proposed curved origami has a different mechanical behavior compared to the corresponding simple flexible arch, specifically if realized by silicon rubbers. By arranging anisotropic friction to the feet, the origami robot can crawl with an omega-elongation/compression motion like an inchworm. With a closed-loop current source control system using a high-frequency pulse width modulation-based topology, where the strain state of the arched origami is detected by a demodulator-free fiber Bragg grating sensor, the average speed of the origami crawling robot can reach 2.72 mm/s. In addition, by arranging three graded Miura origami, a gripper capable of lifting a weight of 518.5 g can be formed, where the carried load is over 4.5 times its own weight.
On the force exerted on a non-spherical asymmetric dust grain from homogeneous, stationary, isotropic, non-magnetized plasma
Authors: Krasheninnikov S. I. , Smirnov R. D.
Published: February 2024

Whereas the conventional wisdom suggests that the force between non-magnetized homogeneous, stationary, isotropic plasma, and the dust grain is only possible for the case of relative plasma–grain velocity, it is shown that stationary non-spherical asymmetric dust grain immersed in stationary, non-magnetized, isotropic plasma can experience a force caused by the grain–plasma interactions. The component of the force due to scattering of plasma particles in the limit of infinite Debye length is considered analytically. Both the particle scattering and absorption force components are modeled numerically in the limits of infinite and finite Debye length using a newly developed 2D3V Aspherical Particle-in-Cell code. The code simulates interactions of dust grain of selected non-spherical asymmetric shape with plasmas using dust shape conforming coordinates. The simulations confirm the existence of the force on non-spherical asymmetric grain in stationary non-magnetized plasma and show that the plasma screening effects can lead to reversal of the force direction.
Data-driven identification and pressure fields prediction for parallel twin cylinders based on POD and DMD method
Authors: Min Guangyun , Jiang Naibin
Published: February 2024

The mode analysis of parallel twin cylinders is conducted in this paper using two data-driven methods: proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD). First, a high-fidelity computational fluid dynamics (CFD) model of parallel twin cylinders is established, and numerical simulations of the model are carried out. Subsequently, the fundamental principles of the POD and DMD algorithms are systematically introduced. Utilizing snapshots obtained from the high-fidelity CFD model, the POD and DMD methods are employed to extract the dominant flow structures. Furthermore, a comparison between the two data-driven methods is conducted by analyzing modal frequencies, pressure distribution, and the reconstruction errors of pressure fields. Finally, the pressure fields of non-sample points are predicted based on the POD–backpropagation neural network (BPNN) surrogate model and the DMD method, and the predicted results are compared with the CFD simulation results. It found that (i) the DMD method is capable of extracting the main coherent structures of the pressure fields, directly obtaining flow modes and their corresponding frequencies, and assessing the stability of flow modes; (ii) the DMD method can capture the main flow features of the pressure fields in both spatial and temporal dimensions, while the POD method is primarily efficient at capturing the spatial features of the pressure fields; (iii) in contrast to the frequency-ranked DMD method, the energy-ranked POD method can reconstruct the pressure fields using a smaller number of modes, indicating that the POD method has an advantage in terms of mode reduction; (iv) in contrast to the energy-ranked POD method, the frequency-ranked DMD method has a wider applicability to the range of flow types and has more advantages in stability analysis of complex dynamic systems; (v) the predicted pressure fields around the cylinder using the first five-order POD modes or DMD modes closely align with CFD calculation results. Additionally, the evolution of pressure fields predicted by the POD–BPNN surrogate model with the first five-order POD modes or the DMD method with the first 200-order DMD modes significantly agrees with CFD simulation results; (vi) the combined use of the POD–BPNN surrogate model and DMD methods allows efficient interpolation and extrapolation of samples, delivering exceptional predictive performance. This study offers insight into the coherent structures in parallel twin cylinders.
Origin of hole mobility anisotropy in 4H-SiC
Authors: Ishikawa Ryoya , Tanaka Hajime , Kaneko Mitsuaki , Kimoto Tsunenobu
Published: February 2024

Hole mobility anisotropy in 4H-SiC was investigated based on both experimental and theoretical approaches. First, the authors established a complete database of the anisotropic hole mobility along both directions parallel and perpendicular to the c-axis in 4H-SiC over the wide acceptor density and temperature ranges by preparing Hall bar structures on p-type SiC(112¯0) epitaxial layers. Empirical equations for the mobility along each direction vs the acceptor density and temperature were determined, which should be useful for the simulation and designing of any SiC devices. In addition to that, the anisotropy in the hole mobility was extracted from the experimental results, and its origin was discussed focusing on that in the effective mass (m∗) of holes. The obtained mobility ratio was far from the m∗ ratio at the valence band maximum, and an averaged m∗ along each direction was determined by theoretical calculation taking into account the energy distribution of holes. Consequently, the authors revealed that the anisotropic hole mobility is explained quantitatively by the anisotropic m∗ considering the E–k dispersion over the entire first Brillouin zone.
Photodissociation of the CH2Br radical: A theoretical study
Authors: Charfeddine F. , Zanchet A. , Yazidi O. , Cuevas C. A. , Saiz-Lopez A. , Bañares L. , García-Vela A.
Published: February 2024

Bromine atom (Br) reactions lead to ozone depletion in the troposphere and stratosphere. Photodegradation of bromocarbons is one of the main sources of bromine atoms in the atmosphere. Here, we use high-level ab initio methods, including spin–orbit effects, to study the photodissociation of the CH2Br radical. All possible fragmentation pathways, namely CH2Br + hν → CH2 + Br, HCBr + H, and CBr + H2, have been analyzed. Potential-energy curves of the ground and several excited electronic states along the corresponding dissociating bond distance of each pathway have been calculated. Considering the actinic fluxes of solar irradiation in the troposphere and in the stratosphere in the relevant range of frequencies, it is found that the first five excited states of CH2Br can be accessed from the ground state. Analysis of the potential curves shows that the pathways producing CH2 + Br and HCBr + H can proceed through a fast direct dissociation mechanism, while the pathway leading to CBr + H2 involves much slower dissociation mechanisms like internal conversion between electronic states, predissociation, or tunneling through exit barriers. The main implications are that the two faster channels are predicted to be dominant, and the slower pathway is expected to be less relevant. The tropospheric and stratospheric solar actinic fluxes also allow for further dissociation of the HCBr and CBr fragments, generating additional Br atoms, provided that they survive possible collisions with other atmospheric reagents. Finally, we discuss the possible effect of each of the three CH2Br dissociation pathways on the depletion of atmospheric ozone.
Flow analysis through a randomly packed pebble-bed geometry using computational fluid dynamics
Authors: Lanade David , Bovati Davalos Octavio , Menezes Craig , Hassan Yassin
Published: February 2024

This study presents a comprehensive analysis of the flow behavior in packed pebble-bed reactors using computational fluid dynamics (CFD) simulations. The pebble-bed geometry corresponds to an experimental facility located at the Texas A&M Thermal-Hydraulics Research Laboratory. The unsteady Reynolds-averaged Navier–Stokes (URANS) k−ω shear stress transport (SST) and the large eddy simulation (LES) approaches were selected to model the turbulence at different Reynolds numbers. The numerical models were first validated by comparing the pressure drop results obtained from the simulations against established correlations, finding the simulation predictions in accurate agreement. Secondly, the velocity first-order statistics from the URANS k−ω SST and LES calculations were also contrasted with the available experimental particle image velocimetry data to validate the numerical models. Results were found in reasonable agreement as the mean absolute error achieved values smaller than 10% of the inlet velocity for most of the analyzed velocity profiles. A comprehensive turbulence characterization was performed, including second-order statistics, Reynolds stress anisotropy, and turbulent kinetic energy production. The proper orthogonal decomposition of the fluctuating velocity was examined in the current flow domain. The turbulence characterization revealed the complex nature of turbulence in packed pebble-bed geometries, which is further complicated by the presence of an enclosing wall. Overall, the findings of this study provide a solid foundation for the development of more accurate CFD-based methodologies for predicting the behavior of flow through packed pebble-bed reactors.
Robust room-temperature anomalous Nernst effect over a broad thickness and composition range in chemically disordered FexPt100−x films
Authors: Liu Zhenyang , Li Guannan , Fu Hao , Lu Yuming
Published: February 2024

The anomalous Nernst effect (ANE) has been under consideration for potential transverse thermoelectric applications. However, the utilized material systems are generally limited to chemically ordered crystals with notable features of nontrivial band topology and/or strong spin–orbit coupling, such as topological ferromagnets and antiferromagnets. In this study, we present the observation of a robust room-temperature ANE in a chemically disordered ferromagnet, specifically an A1-type FexPt100−x alloy. The observed anomalous Nernst thermopower Sxy (∼1.6 μV/K) remains stable over a wide range of thicknesses (6 ≤ t ≤ 100 nm) and compositions (46 ≤ x ≤ 67), which is in stark contrast to the common situation in topological ferromagnets. This behavior can be attributed to both the large anomalous Nernst conductivity αxy (∼1.3 A K−1 m−1), originating from Berry phase effects, as well as the significant Seebeck-driven anomalous Hall effect that modulates its action through mean-free-path and two-carrier models.
Time evolution of natural orbitals in ab initio molecular dynamics
Authors: Rivero Santamaría Alejandro , Piris Mario
Published: February 2024

This work combines for the first time ab initio molecular dynamics (AIMD) within the Born–Oppenheimer approximation with a global natural orbital functional (GNOF), an approximate functional of the one-particle reduced density matrix. The most prominent feature of GNOF-AIMD is its ability to display the real-time evolution of natural orbitals, providing detailed information on the time-dependent electronic structure of complex systems and processes, including reactive collisions. The quartet ground-state reaction N(4S) + H2(1Σ) → NH(3Σ) + H(2S) is taken as a validation test. Collision energy influences on integral cross sections for different initial rovibrational states of H2 and rotational-state distributions of the NH product are discussed, showing a good agreement with previous high-quality theoretical results.
Terahertz and far infrared radiation generation in air plasma created by bichromatic subpicosecond laser pulses
Authors: Buožius D. , Balčas G. , Tamulienė V. , Babushkin I. , Morgner U. , Vaičaitis V.
Published: February 2024

Here, we report on terahertz (THz) radiation generation in air driven by the fundamental and second harmonic of Yb:KGW laser pulses with durations of a few hundred femtoseconds. It was found that the spectrum of generated THz pulses surprisingly spans up to 50 THz, which is comparable to that usually obtained using much shorter Ti:sapphire laser pulses. The broad bandwidth is attributed to a strong spatiotemporal reshaping of the pump pulses in a filament. The achieved energy conversion efficiency is comparable to the one usually obtained from much shorter pump pulses and could be further improved by an optimized experimental setup. The obtained results indicate that compact Yb-based sources provide an attractive alternative to much larger and expensive laser systems.
Orbital ordering and ultrafast carrier dynamics anisotropies in orientation-engineered orthorhombic YMnO3 films
Authors: Duong My Ngoc , Chen Yu-Xun , Tzeng Wen-Yen , Amrillah Tahta , Yang Song , Liu Cheng-En , Dimitrov Dimitre Z. , Haw Shu-Chih , Hsu Chia-Hung , Chen Jin-Ming , Lin Jiunn-Yuan , Wu Kaung-Hsiung , Luo Chih-Wei , Chen Chien-Te , Kuo Chang-Yang , Juang Jenh-Yih
Published: February 2024

The rich physical properties unveiled in a plethora of transition and rare-earth metal oxides have been attributed to the intricate interplays between the orbital, charge, and spin degrees of freedom. Among them, rare-earth manganites (RMnO3) have been attracting tremendous attention owing to the ionic size-induced lattice distortion dictated by the Goldschmidt tolerance factor and the substantial Jahn–Teller distortion unique to Mn3+ ions, which evidently have resulted in a variety of emergent characteristics in electronic, magnetic, and orbital ordering. In this work, we deliberately engineered the orientation of a series of orthorhombic YMnO3 (o-YMO) films grown on SrTiO3(100) [STO(100)] and SrTiO3(110) [STO(110)] substrates by means of pulsed laser deposition. The x-ray diffraction (XRD) and reciprocal space mapping revealed that o-YMO/STO(100) is c-axis-oriented and o-YMO/STO(110) is a-axis-oriented, respectively. The XRD ϕ-scans further indicate that both films have excellent in-plane crystallinity, allowing the exploration of anisotropies along the respective crystallographic orientations. Indeed, the x-ray absorption linear dichroism spectroscopy taken along the respective crystallographic orientations evidently exhibited substantial anisotropy. Theoretical fitting with configuration interaction cluster calculations suggests that the d3z2−r2 orbitals are parallel to YMO[001]/(100), leading to stronger electron scattering along the c-axis. Independent polarization-dependent Δ R/R spectra obtained using the femtosecond pump–probe method exhibited substantial anisotropic behaviors in carrier relaxation dynamics when probing along different crystallographic orientations, presumably due to orbital ordering anisotropies.
Ceiling effect of flapping wing rotorcrafts to enable energy-efficient perching
Authors: Liu Fangyuan , Li Song , Dong Xin , Xiang Jinwu , Li Daochun , Tu Zhan
Published: February 2024

Flapping wing rotorcrafts (FWRs) combine both the motion characteristics of flapping and rotary wings, exhibiting high aerodynamic efficiency at low Reynolds numbers. In this paper, the ceiling effect of FWRs has been studied through numerical and experimental methods to further investigate the aerodynamic performance of FWRs operating under a ceiling and to explore the feasibility of enhancing the flight efficiency of FWRs via ceiling-effect-based perching locomotion. Based on the momentum theory and blade element methods, a theoretical model is first established to predict the additional thrust generated by the FWR operating under the ceiling. Additionally, to uncover the detailed aerodynamic mechanisms of FWRs' ceiling effect, the computational fluid dynamics (CFD) simulations were conducted to analyze the changes in force production and flow field around the FWR at 75–115 mm distances from the ceiling. Furthermore, experimental methods were employed to validate the theoretical model and CFD simulation. The results demonstrate a continuous increase in the thrust from 19.18 to 22.15 gf as the ceiling distance decreases, while the total energy consumption remains relatively constant. Leveraging the ceiling effect, the tested FWR could achieve an additional lift force of up to 9.5% at 75 mm ceiling height with a 33 Hz flapping frequency. Finally, a ceiling perching demonstration was conducted to validate the feasibility of achieving FWRs' energy-efficient locomotion based on ceiling effects. Our study highlights the positive influence of ceiling effect on FWRs, showing a promising way to further improve the flight efficiency of FWRs.
Enhancing the quality of homoepitaxial (−201) β-Ga2O3 thin film by MOCVD with in situ pulsed indium
Authors: Wang Yao , Li Jiale , Zhang Tao , Wu Wenkai , Li Wenji , Yao Yixin , Wang Ziming , Feng Qian , Zhang Yachao , Zhang Jincheng , Hao Yue
Published: February 2024

This article innovatively uses pulsed metal-organic chemical vapor deposition technology to optimize the quality of β-Ga2O3 thin films on (−201) β-Ga2O3 homo-substrate using indium pulse-assisted technology. The results demonstrate that the pulsed indium-assisted method, when compared with the traditional indium-assisted method, effectively suppresses the desorption of Ga2O, enhances the flatness of the β-Ga2O3 film, and reduces the surface roughness from 34.8 to 0.98 nm. The optimized single crystalline β-Ga2O3 film was grown with pulsed-indium, and the full width at half maximum of x-ray diffraction rocking curve was 30.42 arc sec, smaller than that of the continuous indium β-Ga2O3 (56.1 arc sec). In combination with the x-ray photoelectron spectroscopy O1s split-peak fitting analysis, the relative content of oxygen vacancies in the film was significantly reduced by pulsed indium-assisted method. The Hall mobility of films assisted by pulsed-indium is approximately 14 times higher than that of films assisted by traditional indium. The pulsed indium technology provides an idea for homoepitaxial growth of high-quality β-Ga2O3 films.
Computing the frequency-dependent NMR relaxation of 1H nuclei in liquid water
Authors: Paschek Dietmar , Busch Johanna , Mock Eduard , Ludwig Ralf , Strate Anne
Published: February 2024

We present a computational framework for reliably determining the frequency-dependent intermolecular and intramolecular nuclear magnetic resonance (NMR) dipole–dipole relaxation rates of spin 1/2 nuclei from Molecular Dynamics (MD) simulations. This approach avoids the alterations caused by the well-known finite-size effects of translational diffusion. Moreover, a procedure is derived to control and correct for effects caused by fixed distance-sampling cutoffs and periodic boundary conditions. By construction, this approach is capable of accurately predicting the correct low-frequency scaling behavior of the intermolecular NMR dipole–dipole relaxation rate and thus allows for the reliable calculation of the frequency-dependent relaxation rate over many orders of magnitude. Our approach is based on the utilization of the theory of Hwang and Freed for the intermolecular dipole–dipole correlation function and its corresponding spectral density [L.-P. Hwang and J. H. Freed, J. Chem. Phys. 63, 4017–4025 (1975)] and its combination with data from MD simulations. The deviations from the Hwang and Freed theory caused by periodic boundary conditions and sampling distance cutoffs are quantified by means of random walker Monte Carlo simulations. An expression based on the Hwang and Freed theory is also suggested for correcting those effects. As a proof of principle, our approach is demonstrated by computing the frequency-dependent intermolecular and intramolecular dipolar NMR relaxation rates of 1H nuclei in liquid water at 273 and 298 K based on the simulations of the TIP4P/2005 model. Our calculations are suggesting that the intermolecular contribution to the 1H NMR relaxation rate of the TIP4P/2005 model in the extreme narrowing limit has previously been substantially underestimated.
High-performance aqueous zinc-ion battery cathodes: Enhanced performance with V2O5/graphene sandwich-like heterostructures featuring structural defects
Authors: Selvam Tharani , Dhinasekaran Durgalakshmi , Subramanian Balakumar , Rajendran Ajay Rakkesh
Published: February 2024

Aqueous zinc-ion batteries (AZIBs) are considered promising candidates for future energy storage systems because of their outstanding safety record, affordability, and environmentally friendly features. However, their practical application has been hindered by the limited performance of cathode materials. In this study, we present an innovative method to enhance the electrochemical performance of AZIB cathodes by constructing sandwich-like heterostructures of V2O5/graphene with structural defects. The resulting cathode material exhibits superior electrochemical properties, including a high specific capacity of 572.1 at 0.1 A g−1, outstanding rate capability, and long-term cycling stability. The capacity retention and the coulombic efficiency of the material were around 90.4% and 91.6%, respectively, even after 10 000 cycles at 5.0 A g−1. This research aims to provide valuable insights into designing advanced cathode materials for AZIBs, paving the way for their widespread commercialization.
Suppressed lattice thermal conductivity in porous compounds for high-performance thermoelectric applications
Authors: Zhang Xuebo , Dong Tieshuan , Li Yaobo , Zhai Jingwen , Feng Zhenzhen , Yan Yuli , Zeng Zaiping
Published: February 2024

Traditional zinc blende semiconductor materials of groups II–VI and III–V exhibit excellent electrical properties, yet suffer from oversized lattice thermal conductivity, causing poor thermoelectric performance. Herein, we have explored an alternative metastable phase of those materials, namely, porous phase. Compared with the stable zinc blende structure, which has simple crystal structure with nearly isotropic bonding feature, porous compounds exhibit complex bonding hierarchy and softened acoustic phonon modes with strong anharmonicity, reducing the lattice thermal conductivity by nearly two orders of magnitude. As an outstanding representative of porous compound family, the suppressed thermal conductivity [∼0.76 W/(m K) at room temperature] combined with enhanced Seebeck coefficient makes porous MgTe a high-performance thermoelectric material with figure of merit above unity at n-type doping and high temperature. This work highlights the important role of intrinsic porosity in design of high-performance thermoelectric materials with low lattice thermal conductivity.
Structural and semantic features of adjectives across languages and registers
Authors: Ebeling Signe Oksefjell
Published: February 2024

This study focuses on the seemingly simple grammatical category of adjectives. However, the framework adopted for analysing adjectives from both a cross-linguistic and a cross-register perspective highlights features of grammatical complexity within phrases as well as contrastive complexity within and across languages and registers. Using English-Norwegian comparable data from the fictional sub-registers of narrative and dialogue, the analysis uncovers both similarities and differences in the structural and semantic features of adjectives. Most notable is perhaps the impact of register at all levels of analysis, including adjectival function (attributive vs. predicative), the degree of phrase complexity and semantic class. The contrastive analysis proper, i.e. comparing adjective use across languages, reveals that English and Norwegian have more in common within each sub-register than across them. For example, the lexico-grammatical behaviour of adjectives in English narrative has more in common with Norwegian narrative than it has with English dialogue. To the extent that there are clear general differences between English and Norwegian, these are mainly found in the proportions and preferences of a few specific features.
Electrical properties of strained off-stoichiometric Cu–Cr–O delafossite thin films
Authors: Moreira Marco , Crêpellière Jonathan , Polesel-Maris Jérôme , Leturcq Renaud , Guillot Jérôme , Fleming Yves , Lunca-Popa Petru
Published: February 2024

Off-stoichiometric Cu–Cr–O delafossite thin films with different thicknesses were grown by metal organic chemical vapor deposition on substrates with different coefficients of thermal expansion. Seebeck thermoelectric coefficient and resistivity measurements were performed on the range of 300–850 K. A qualitative change in the temperature-dependence of the resistivity is observed at the temperature corresponding to the deposition process, where the transition from tensile to compressive strain takes place. Arrhenius plots reveal different slopes in these two thermal ranges. The fact that the shift is more pronounced for the thinner films might indicate the induced strain plays a role in changing electrical behaviour. Furthermore, changes below 0.1% in electrical mobility were measured when the strain is induced by mechanical bending.
Unusual multiple magnetic transitions and anomalous Hall effect observed in antiferromagnetic Weyl semimetal, Mn2.94Ge (Ge-rich)
Authors: Ghosh Susanta , Low Achintya , Changdar Susmita , Purwar Shubham , Thirupathaiah Setti
Published: February 2024

We report on the magnetic and Hall effect measurements of the magnetic Weyl semimetal, Mn2.94Ge (Ge-rich) single crystal. From the magnetic properties study, we identify unusual multiple magnetic transitions below the N

e
ˊ

el temperature of 353 K, such as the spin-reorientation (T
SR) and ferromagnetic-like transitions. Consistent with the magnetic properties, the Hall effect study shows unusual behavior around the spin-reorientation transition. Specifically, the anomalous Hall conductivity increases with increasing temperature, reaching a maximum at T
SR, which then gradually decreases with increasing temperature. This observation is quite in contrast to the Mn

3
+
δ

Ge (Mn-rich) system, though both compositions share the same hexagonal crystal symmetry. This study unravels the sensitivity of magnetic and topological properties on the Mn concentration.
Dynamic modeling and force-vibration mapping mechanism construction of rolling bearings considering cage flexibility and local faults
Authors: Zhang Xinyin , Shi Juanjuan , Luo Yang , Yu Yihao , Shen Changqing , Zhu Zhongkui
Published: February 2024

Rolling bearings are one of important components of rotating machinery transmissions and thus its health condition is important for the safety of machinery. Thus, rolling bearing vibration analysis is critical for bearing health condition monitoring. Current bearing vibration analysis ignores multiple compound influencing factors for dynamic modeling. Hence, a more accurate bearing dynamic model, considering multiple factors including cage flexibility, time-varying displacement excitations caused by local defects and elastohydrodynamic (EHD) lubrication, is proposed to accurately reflect force states among bearing elements and vibration responses of bearings. Furthermore, the force states and vibration responses of bearings with localized defects in the proposed model are analyzed in details: (1) the main excitation source of the dynamic model under faulty conditions is identified as the contact force between the rolling element and the raceway by analyzing the vibration signals and main physical variables (the contact forces and the friction forces) in numerical values and change trends; (2) the mapping mechanism between the main excitation source and the vibration response is constructed. The force states among bearing elements are detailedly analyzed in the proposed model and the relationship between the forces and bearing vibration responses is revealed, facilitating the bearing health condition monitoring and vibration control of machinery.
Dynamic probability modeling-based inspection intervals optimization for civil aircraft composite structures using Bayesian updating
Authors: Li Xin , Zuo Hongfu , Yang Bin
Published: February 2024

The evaluation of damage tolerance in composite materials is essential for ensuring the safety of aircraft structures. One of the most challenging aspects of applying probability modeling-based methods to evaluate damage tolerance is determining the actual damage size distributions for in-service aircraft structures. Although existing nondeterministic approaches have been used to optimize inspection intervals of composite structures, few studies have investigated the effects of updates on the actual damage size distribution and its impact on both the probability of structural failure and inspection intervals. This paper proposes a dynamic optimization method for inspection intervals of composite structures based on Bayesian updating. The damage size distribution of the composite structure is characterized by a general stochastic distribution. A Bayesian updating methodology is presented to iteratively update the actual damage size distribution whenever new data becomes available. Based on the constructed probability model, the inspection intervals of composite structures are determined under the objectives of optimal safety and economy for civil aircraft using a Monte Carlo approach. Compared to prior distribution models, the proposed method achieves higher safety for structures during a single inspection, reduces the failure probability of structures throughout their entire service life, and incurs lower maintenance costs. It also enables maintenance personnel to flexibly adjust inspection intervals while facilitating quantitative evaluation of both failure probabilities and maintenance costs associated with these intervals. These findings suggest that the proposed method holds great potential in enabling maintenance personnel to make informed decisions regarding inspection intervals for improved safety and economic performance.
Spectroscopic studies of TeO2-based glasses doped with Sm3+ and its use as an optical temperature sensor
Authors: Gunha Jaqueline Valeski , Sales Tasso O , Muniz Robson Ferrari , Silva Wagner F , Somer Aloisi , Jacinto Carlos , Dias Daniele Toniolo , El-Mallawany R , Astrath Nelson Guilherme Castelli , Novatski Andressa
Published: February 2024

This study reports the synthesis and characterization of glasses in the (100-x)65TeO2-15Li2O-20ZnO + xSm2O3 system doped with Sm2O3, denoted as Sm3+: TLZ glasses, with varying doping concentrations from 0.1, 0.15, 0.2, 0.35, 0.5, and 1 mol%. The structural and optical properties, as well as the temperature dependence of luminescence, were investigated. Excitation at 405nm resulted in strong orange-red luminescence at 566, 600, and 646 nm. The local environment surrounding Sm3+ ions was explored using the intensity ratio of electric and magnetic dipole transitions. The non-radiative energy transfer between neighboring Sm3+ ions was evaluated using the Inokuti-Hirayama model, allowing for the determination of the critical transfer distance. The temperature dependence of luminescence, displayed by Commission Internationale de L’Eclairage (CIE) chromaticity coordinates, exhibited a monotonic change from (0.611, 0.387) at 295 K to (0.605, 0.393) at 479 K. The Sm3+:TLZ glasses doped with 0.15 mol% showed the highest relative thermal sensitivity of 0.10%K-1 at 479 K, suggesting their potential as luminescent thermometers.
Systematic study of two proton radioactivity within the effective liquid drop model
Authors: Saeed Abdulla N P , Preethi Rajan M K , Biju R K
Published: February 2024

In this study, we investigated two-proton radioactivity using the effective liquid drop model with varying mass asymmetry shapes and effective inertia coefficients (VMAS-EFF). Gaudin’s expression term for Coulomb potential energy is replaced in the current study’s calculation of potential energy. The VMAS-EFF combination predicts the half-life with the lowest standard deviation (

σ

=1.03) compared to other models and previous constant mass asymmetry with Werner-inertial Wheeler’s coefficient combinations. The lowest standard deviation value indicates that the VMAS-EFF combination is suitable for reproducing the experimental data. We extended the half-life predictions to another 54 nuclei and compared them with six theoretical model predictions and two empirical formula predictions. The present work also investigated the decay possibilities using quantum tunnelling by computing the driving potential (V-Q) for various states of angular momentum l = 0, 2, 3, and 4. Found that 6Be, 6B, 8C, 12O,15,16Ne, 19Mg, 22Si, 26S, 30Ar 38,39Ti, 40V, 42Cr, 45Fe, 48,49Ni, 54Zn, 58,59,60Ge and 64Se nuclei have a high chance of emission for two protons, while 7B, 10N, 14F, 17Na, 24P, 28Cl,32K, 34Ca, 36,37Sc, 44Mn, 47Co, 52Cu, 56,57,58Ga, 61,62As nuclei have a lower chance for two proton than one proton decay. The computation of separation energy findings agree well with the driving potential findings.
Water activation products generation and transport in DEMO divertor
Authors: Chiovaro P. , Quartararo A. , Avona P. , Bongiovì G. , Di Maio P.A. , Giambrone S. , Moscato I. , Vallone E.
Published: February 2024

In water-cooled nuclear reactors, the issue of neutron-activated products transport along the primary heat transfer system (PHTS) is very demanding, as it is a coupled neutronic/fluid-dynamic problem requiring a challenging balance between accuracy and reasonable computational time. This work addresses the transport of water activation products in large hydraulic circuits. Regarding the nuclear calculations, the assessment of the production rates of the radioisotope concentrations has been performed by Monte Carlo analyses adopting the MCNP5.1.6 code, while for the transportation calculations, an innovative method has been expressly developed. It foresees a one-dimensional nodalization, in a MATLAB-Simulink environment, of the hydraulic circuit considered with a computational fluid-dynamic (CFD) characterization (by ANSYS CFX code) of the nodes under neutron flux, that is the components where radioisotopes are formed, and the highest gradients of concentration are present. The method was compared with one-dimensional models not supported by fluid-dynamic analysis. The results of this comparison showed that in cases involving fairly complicated geometries and radioisotopes with a small half-life, CFD analyses are necessary to achieve adequate accuracy. The procedure was applied to very large and rather complex hydraulic circuits like the divertor PHTSs of DEMO fusion reactor to obtain the concentrations of the activation products of the water constituents (16N, 17N, 19O, 14C, 41Ar) along such systems.
X-Arapuca long term test
Authors: Andreossi V. , Balmforth Z. , Bergamini Machado A.A. , Botogoske G. , Canci N. , Di Capua F. , Fiorillo G. , Grauso G. , Matteucci G. , Ravinthiran S. , Segreto E. , Suvorov Y.
Published: February 2024

The photon detection system of the DUNE experiment is based on the X-ARAPUCA light
trap. The basic elements of the X-ARAPUCA are the dichroic filters coated with wavelength shifter
(para-Therphenyl), a waveshifting plate and an array of SiPMs which detects the trapped photons. A
small scale prototype of the X-ARAPUCA has been installed in liquid argon in a dedicated facility
at INFN-Napoli and exposed to alpha particles from a source. In order to test the stability of
the overall device response the X-ARAPUCA was kept for 10 days in continuously purified liquid
argon. The performed tests allowed for a preliminary estimation of the X-ARAPUCA absolute photon
detection efficiency.
Drug release control and anti-inflammatory effect of biodegradable polymer surface modified by gas phase chemical functional reaction
Authors: Bae Inho , Kim Byung-Hoon
Published: February 2024

The plasma technique has been widely used to modify the surfaces of materials. The purpose of this study was to evaluate the probability of controlling the prednisolone delivery velocity on a polylactic acid (PLA) surface modified by plasma surface treatment. Surface modification of PLA was performed at a low-pressure radio frequency under conditions of 100 W power, 50 mTorr chamber pressure, 100–200 sccm of flow rate, and Ar, O2, and CH4 gases. The plasma surface-modified PLA was characterized using scanning emission microscope, x-ray photoelectron spectroscopy (XPS), and contact angle measurements. In vitro evaluations were performed to determine cellular response, drug release behavior, and anti-inflammatory effects. The PLA surface morphology was changed to a porous structure (with a depth of approximately 100 μm) and the surface roughness was also significantly increased. The XPS results demonstrated higher oxygenized carbon contents than those in the non-treated PLA group. The prednisolone holding capacity increased and the release was relatively prolonged in the surface-modified PLA group compared to that in the non-treated PLA group. In addition, cell migration and proliferation significantly increased after PLA treatment alone. The activity of cytokines such as cyclooxygenase-2 (COX-2), tumor necrosis factor-a (TNF-α), interleukin (IL-1β), and IL-6 were considerably reduced in the plasma-treated and prednisolone holding group. Taken together, surface-modified PLA by plasma can provide an alternative approach to conventional physicochemical approaches for sustained anti-inflammatory drug release.
Electrospun zein nanofibers loaded with curcumin as a wound dressing: enhancing properties with PSS and PDADMAC layers
Authors: Salehi Nasrin , Ghaee Azadeh , Moris Hanieh , Derhambakhsh Sara , Sharifloo Mehdi Mansour , Safshekan Farzaneh
Published: February 2024

Development of wound dressings with enhanced therapeutic properties is of great interest in the modern healthcare. In this study, a zein-based nanofibrous wound dressing containing curcumin as a therapeutic agent was fabricated through electrospinning technique. In order to achieve desirable properties, such as antibacterial characteristics, reduced contact angle, and enhanced mechanical properties, the layer-by-layer technique was used for coating the surfaces of drug-loaded nanofibers by sequentially incorporating poly (sodium 4-styrene sulfonate) as a polyanion and poly (diallyldimethylammonium chloride) (PDADMAC) as a polycation. Various analyses, including scanning electron microscopy, Fourier transform infrared spectroscopy, drug release assessment., and mechanical tests were employed to assess the characteristics of the prepared wound dressings. Based on the results, coating with polyelectrolytes enhanced the Young’s modulus and tensile strength of the electrospun mat from 1.34 MPa and 4.21 MPa to 1.88 MPa and 8.83 MPa, respectively. The coating also improved the controlled release of curcumin and antioxidant activity, while the outer layer, PDADMAC, exhibited antibacterial properties. The cell viability tests proved the appropriate biocompatibility of the prepared wound dressings. Moreover, our findings show that incorporation of the coating layers enhances cell migration and provides a favorable surface for cell attachment. According to the findings of this study, the fabricated nanofibrous wound dressing can be considered a promising and effective therapeutic intervention for wound management, facilitating the healing process.
Stimuli-triggered multilayer films in response to temperature and ionic strength changes for controlled favipiravir drug release
Authors: Xu Li , He Lang , Li Yinzhao , Cai Tingwei , Zhang Jianhua , Chu Zihan , Shen Xiaochen , Cai Raymond , Shi Haifeng , Zhu Chunyin
Published: February 2024

The block copolymer micelles and natural biopolymers were utilized to form layer-by-layer (LbL) films via electrostatic interaction, which were able to effectively load and controllably release favipiravir, a potential drug for the treatment of coronavirus epidemic. The LbL films demonstrated reversible swelling/shrinking behavior along with the manipulation of temperature, which could also maintain the integrity in the structure and the morphology. Due to dehydration of environmentally responsive building blocks, the drug release rate from the films was decelerated by elevating environmental temperature and ionic strength. In addition, the pulsed release of favipiravir was observed from the multilayer films under the trigger of temperature, which ensured the precise control in the content of the therapeutic reagents at a desired time point. The nanoparticle-based LbL films could be used for on-demand in vitro release of chemotherapeutic reagents.
Methods to improve antibacterial properties of PEEK: A review
Authors: Uysal Idil , Tezcaner Ayşen , Evis Zafer
Published: February 2024

As a thermoplastic and bioinert polymer, polyether ether ketone (PEEK) serves as spine implants, femoral stems, cranial implants, and joint arthroplasty implants due to its mechanical properties resembling the cortical bone, chemical stability, and radiolucency. Although there are standards and antibiotic treatments for infection control during and after surgery, the infection risk is lowered but can not be eliminated. The antibacterial properties of PEEK implants should be improved to provide better infection control. This review includes the strategies for enhancing the antibacterial properties of PEEK in four categories: immobilization of functional materials and functional groups, forming nanocomposites, changing surface topography, and coating with antibacterial material. The measuring methods of antibacterial properties of the current studies of PEEK are explained in detail under quantitative, qualitative, and in vivo methods. The mechanisms of bacterial inhibition by reactive oxygen species generation, contact killing, trap killing, and limited bacterial adhesion on hydrophobic surfaces are explained with corresponding antibacterial compounds or techniques. The prospective analysis of the current studies is done, and dual systems combining osteogenic and antibacterial agents immobilized on the surface of PEEK are found the promising solution for a better implant design.