bluuebunny/crossref_metadata_2025 huggingface dataset:
RLL-realization and its Hopf superalgebra structure of Up,q(gl̂(m|n))
Authors: Hu Naihong , Jing Naihuan , Zhong Xin
Published: December 2024

In this paper we extend the Reshetikhin–Semenov–Tian–Shansky formulation of quantum affine algebras to the two-parameter quantum affine superalgebra Up,q(gl̂(m|n)) and obtain its Drinfeld realization. We also derive its Hopf algebra structure by providing Drinfeld-type coproduct for the Drinfeld generators.
Abrupt X-to-O-wave structural field transition in presence of anomalous dispersion
Authors: Hall Layton A. , Abouraddy Ayman F.
Published: December 2024

All linear, propagation-invariant, paraxial pulsed beams are spatiotemporally X-shaped (conical waves) in the absence of group-velocity dispersion (GVD) or in the presence of normal GVD. It is known, however, that such conical waves become O-shaped in the presence of anomalous GVD, resulting in a field profile that is circularly symmetric in space and time. To date, experiments generating conical waves in which the wavelength of a high-energy pump laser is tuned across the zero-dispersion wavelength of a nonlinear medium have not revealed the expected X-to-O-wave structural field transition. We report here an unambiguous observation of a fixed-central-wavelength X-to-O-wave structural field transition occurring in linear dispersion-free wave packets in the anomalous GVD regime, without needing to change the sign or magnitude of the GVD. Instead, by tuning the group velocity of a space–time wave packet (STWP) across a threshold value that we call the “escape velocity,” we observe an abrupt transition in the STWP from an O-shaped to an X-shaped spatiotemporal profile. This transition is associated with an abrupt change in the associated spatiotemporal spectrum of the STWP: from closed elliptical spatiotemporal spectra below the escape velocity to open hyperbolic spectra above it. These results may furnish new opportunities for engineering the phase-matching conditions in nonlinear and quantum optics.
Partial loss and significant depletion of radiation belt electrons during the April 4, 2017, geomagnetic storm
Authors: Zou Zhengyang , Hu Jiahui , San Wen , Yuan Qitong
Published: December 2024

We report a specular loss event of radiation belt electrons induced by a moderate geomagnetic storm on April 4, 2017, by using Van Allen Probe observations. During the initial phase, when the solar wind dynamic pressure (Pdyn) reached 12 nPa, the radiation belt electrons at Ek > ∼200 keV experienced a partial loss, followed by noticeable energy dispersion, which pronouncedly occurred at larger pitch angles on higher L shells. During the main phase, both probes witnessed a significant electron flux depletion at all energies from 54 to 2.6 MeV on the dusk-night side (MLT = magnetic local time around 20). Moreover, the corresponding phase space density (PSD) shows a local dip within L* = 4.44–4.87 (drift shell under adiabatic coordinate), which is not the outermost of L*, lasting for one pass (semi-period) of the spacecraft and quickly disappearing. By comparing the characteristics of electron loss in response to variations of the solar wind and geomagnetic indices, the movement of the estimated magnetopause location and the last closed drift shells, as well as the distribution of the plasma waves, we find that the partial dropout was essentially induced by the magnetopause shadowing effect, while the potential effect of the subsequent local PSD dip cannot be clearly explained by the present theory as far as we know. By showing the specular dropout event in the present work, we underline that the different loss effects should draw special attention from the space physics community.
Aerodynamic characteristic of limited micro-scale Taylor–Couette flow at hyper-rotate speed
Authors: Lyu Yuan-wei , Huang Pu , Zhang Jing-yang , Liu Yuan , Zhang Jing-zhou
Published: December 2024

To pursue improvements in the power-to-weight ratio, cost-effectiveness ratio, and reliability in the energy industry, rotating machinery has been developed with higher rotational speeds and smaller sizes, resulting in complex aerodynamic behavior of the rotational shearing flow between rotator and stator. This study reports experimental measurements of the aerodynamic characteristics of a limited micro-scale Taylor–Couette flow (TC flow) at hyper-rotational speeds for the first time. The maximum rotational speed and eccentricity ratio are 6.0 × 104 rpm and 0.8, respectively, and the minimum average clearance height is 100 μm. The static pressure of the shearing flow is measured using a high-response micro-manometer. A large eddy simulation has been employed to unveil flow fields of the gas film between the stator and the rotator. The results show that the micrometer-scale clearance height and end leakage due to limited length dominate the micro-scale Taylor–Couette flow. Decreasing the scale of the clearance height reduces the angular distance between the peak and bottom pressures compared to that observed in the TC flow with a large-scale clearance. Furthermore, ambient pressure cannot fully permeate into central section of the eccentric Taylor–Couette flow with a micrometer-scale clearance and end leakage, and the pressure upstream near the region the minimum size of clearance decreases along the axial end. Owing to the difference in the constraint degree at both ends along the axial direction, the peak value occurs near the region of Z/L = −0.32. The maximum pressure of the limited micro-scale Taylor–Couette flow increases with increasing rotational speed and eccentricity ratio, whereas it decreases with increasing clearance height. Within the scope of the parameters in this study, the maximum pressure is 0.025 MPa. Decreasing the size of gas film restrains the instability of the shearing flow, whereas increasing the rotational speed strengthens the turbulence. In this study, the shearing flow at the middle section (Z/L = 0) is in a nearly laminar state at δ < 0.012, whereas it is highly turbulent near the end of the clearance and in the ambient environment. The end leakage induces additional axial flow, which is conspicuous at a large eccentricity ratio. At hyper-rotational speeds, the micro-scale Taylor–Couette flow with end leakage exhibits distinctive patterns that have never been reported in classic Taylor–Couette flows with large clearances. This work of this study is significant because it can provide theoretical guidance and technical support for the design of actual dynamic pressure gas bearings and floating ring sealing flow.
Dual-frequency excited combination resonance and global stability of an oscillating cylindrical bubble
Authors: Yu Jiaxin , Luo Jinxin , Zhang Xiangqing , Zhang Yuning , Lu Zhanhui , Zhang Yuning
Published: December 2024

Based on the multi-scale method and Lyapunov stability theory, the second-order analytical model of combination resonance under dual-frequency acoustic excitation of an oscillating cylindrical bubble is established. The nonlinear dynamic characteristics of the additive combination resonance and the subtractive combination resonance are explored by analyzing the frequency response curve and global stability. The primary findings are given as follows: (1) the combination resonance exhibits complex dynamic characteristics, which are manifested in the frequency response curve as multiple response peaks and unstable regions. (2) The response peak of the additive combination resonance consists of a single resonance peak on the left and a small-amplitude double peak on the right. The response amplitude is highly sensitive to changes in core parameters, and the changes at the top of the response peak are obvious. (3) The response peak of the subtractive combination resonance is composed of a large-amplitude double-peak resonance on the left and a small-amplitude single-peak resonance on the right. When the frequency is relatively high, three discontinuous unstable regions will appear in the frequency response curve.
Experimental study on aeration characteristics of plunging wave impact on a vertical cylinder
Authors: Ma Zhe , Zhang Ling , Sun Jiawen , Gao Mingyue , Zhai Gangjun
Published: December 2024

The impact force exerted by plunging breakers on structures is most pronounced, with the impact pressure being most sensitive to the changes in air entrainment, posing a threat to the structural safety of offshore wind turbines. However, the current explanations of the high impact force mechanisms in plunging waves are relatively superficial, and the relationship between the air entrainment motion and pressure oscillations remains unclear. According to the experimentally obtained pressure characteristics and the formation of entrapped air, this paper systematically divides the process of plunging wave impact on a vertical cylinder into three stages: breaking wave crest impact, entrained air cavity impact, and plume impact. Employing a bubble image velocimetry platform to visualize flow field characteristics and quantify turbulence intensity, we investigated the connection between gas motion and impact loads. The results indicate that the conversion of gas energy is closely related to the load characteristics, with the maximum impact force occurring near the peak of the energy gradient. The gas movement significantly influences pressure oscillations, which are positively correlated with the gas's physical compression and expansion characteristics. This study has uncovered new insights into the phenomenon of plunging waves impacting wind turbine towers and has enhanced the understanding of its load characteristics.
The motion mechanism of a boulder transported by landslide
Authors: Shi Chuanqi , Jiao Jiajun , Sun Yunhui , Wang Xiaoliang , Liu Qingquan , Liu Haoran
Published: December 2024

Various soil-rock mixed landslides occur in the natural environment. Carried along in the slide, boulders will eventually come to rest. The origin of boulder motion provides crucial constraints for inferring geological events. To overcome the challenges posed by the limited visibility within landslides and the subsequent difficulty in observing boulder motion, we propose a novel device to measure three-axis acceleration and angular velocity using Inertial Measurement Unit (IMU) technology. By comparing with the traditional high-speed camera, the efficacy of the IMU sphere is validated. In the study of boulder movements within landslides, we employ the IMU sphere to characterize boulders. Through experiments varying two key parameters—the initial position of the IMU sphere and the mass of fine particles—this study identifies three distinct final deposition states of the IMU sphere: separate, partially submerged, and completely submerged. By analyzing the potential and kinetic energy during the sliding process of the IMU sphere, we delve into the combined effects of motion enhancement due to landslide deformation and motion hindrance as the IMU sphere passes through fine particles, thereby revealing the underlying movement mechanisms of boulders within landslides. Analysis of leading wave heights indicates minimal sensitivity to the initial position of the IMU sphere, with the mass of fine particles exerting the primary influence. At last, through a comprehensive analysis of the IMU sphere's motion, a novel positional parameter is introduced, leading to the identification of motion mechanisms and distinct phase diagrams depicting deposition states.
Stability of finite-length collapsible channel flow to spanwise perturbations
Authors: Herrer E. G. , Herrada M. A. , Gañán-Calvo A. M. , Stewart P. S.
Published: December 2024

We consider flow through a finite-length flexible-walled channel formed by removing a portion from one wall of a wide rigid channel and replacing by a pre-tensioned hyperelastic sheet of finite thickness. The flow is driven by a prescribed upstream flow rate which is uniform along the channel inlet, and so with periodic boundary conditions in the transverse direction the system admits a steady state with a wall profile which is deformed in the streamwise direction but spatially uniform in the spanwise direction. Identical to the planar case, this system exhibits two stable static configurations: an upper branch where the flexible wall is mostly inflated and a lower branch where the wall is highly collapsed. We consider the stability of these steady states to spanwise perturbations, showing that both can become unstable to distinct families of self-excited oscillations. In particular, for large spanwise wavenumbers, these steady states are unstable to oscillatory normal modes where the perturbation wall profile has a single oscillating hump in the streamwise direction, not previously seen in collapsible channel flows driven by fixed upstream flux. Furthermore, for sufficiently large wavenumbers and no wall pre-tension in the spanwise direction, this system is always unstable to a new spanwise non-uniform static configuration, which arises due to the merging of a pair of unstable oscillatory normal modes. However, with non-zero spanwise wall pre-tension, there is always a region of parameter space where the spanwise uniform steady state is stable for all wavenumbers.
Regime map of non-coalescence between two equal-sized uncharged water droplets suspended in oil: A numerical study
Authors: Saifullin D. D. , Lukin D. S. , Samusenko A. V. , Chirkov V. A.
Published: December 2024

This paper is devoted to numerical simulation of collision and consequent separation of conductive same-sized droplets of different sizes (from 0.3 to 2 mm) under the effect of a constant voltage exceeding the threshold of the transition from coalescence to non-coalescence. The computations were based on the arbitrary Lagrangian–Eulerian method—the interface between the two phases was represented as a geometry line that moves in accordance with the calculated fluid velocity throughout the solution of the problem. Four possible modes and ranges of electric field strength values corresponding to them were identified, ranked by their negative impact on the demulsification process: rebound, separation into three or multiple drops, and electrospraying. This includes the narrow ranges of electrospraying beside the “coalescence-non-coalescence” threshold and during the “rebound-multidrops” transition. A “regime map”—a diagram of possible outcomes depending on the size of drops and the electric field strength—was formed and analyzed to summarize the results and identify the most favorable modes of demulsification processes. The map revealed an area when coalescence is substituted with only rebound when drop radius increases, i.e., when there will be no smaller drops after the interaction.
On the onset of thermal convection in a rotating spherical shell with spatially heterogeneous heat source distribution
Authors: Sharma Dheeraj Kumar , Sahoo Swarandeep
Published: December 2024

Thermal convection in rotating spherical shells effectively model the fluid motions occurring in molten cores of planetary interiors. In the Earth's outer core, such convective motions when subjected to spatial varying thermal buoyancy undergo characteristic modifications that fundamentally affect the consequent magnetic field generation. In addition to the extensively explored mechanism of boundary heat flux (BH) variations, the present study majorly focuses on a novel mechanism of heat source heterogeneity (SH)-driven buoyancy forcing, mimicking non-uniform secular cooling in the outer core. The direct effect of heat sources on the temporal evolution of temperature contrasts the heat flux control exerted by BH forcing. The most prominent difference is the capability of SH forcing to modulate the thermo-fluidic state in the entire shell while the BH-driven anomalies are limited to regions close to the outer boundary only. Dynamically, SH forcing is relatively more effective, with weaker heterogeneity causing transformations in the thermo-fluidic patterns analogous to stronger BH cases. Compared to the homogeneous case, SH leads to a reduction in onset threshold, localization of the convective instabilities, concentrated steady thermal winds, the dominance of anti-cyclonic axial helicity, and overall homogenization with smaller scaled spherical harmonic heterogeneity patterns. Moreover, a novel phenomenon of dual onset is observed for the SH configuration only, marking distinctive transitions in the convective instability features with larger variations. Finally, the effect of SH on the thermal state at the boundaries indicate the plausibility of strong core–mantle and outer–inner core interactions with significant geophysical implications.
Wake transitions of the flow around two side-by-side elliptic cylinders
Authors: Phan Thi Dieu Thuy , Nguyen Dinh Thang , Nguyen Van Luc , Tran Tien-Anh , Le Anh Tuan , Nguyen Van Tien , Duong Viet Dung
Published: December 2024

The wake transitions of the flow past two side-by-side elliptical cylinders were numerically investigated using the lattice Boltzmann method at Reynolds numbers (Re) of 40, 100, and 150, with various spacing ratios (L/D, where L represents the distance between the cylinder centers and D is their diameter) and aspect ratios (AR). This study elucidated the effects of Re, AR, and L/D on the flow characteristics, including wake structures, hydrodynamic coefficients, Strouhal number (St), and the spectral energy of the flow exerted on both cylinders. Six distinct flow patterns are observed in the AR−L/D space, such as steady shear layers, anti-phase synchronized streets, in-phase synchronized streets, single bluff body, flip-flopping, and chaotic flow. These patterns were characterized through detailed analyses, including vorticity contour plots, time histories of drag and lift coefficients, power spectral density, and proper orthogonal decomposition of vorticity fluctuations into deterministic spatial structures. Additionally, flow pattern maps and diagrams of the time-averaged pressure coefficients on the surface of the cylinders were provided to assess the influence of Re, AR, and L/D on the flow behavior. The hydrodynamic coefficients of both cylinders showed near-identical trends with significant variations depending on L/D and AR. When AR is small, the time-averaged drag coefficient and the root-mean-squared lift coefficient of both cylinders are found to be substantially higher than those of an isolated elliptical cylinder. Furthermore, a notable increase in the time-averaged lift coefficient was observed when L/D was small, attributed to the repulsive forces between the cylinders. At higher Reynolds numbers (Re=100 & 150), substantial differences in St emerge, particularly for smaller AR values, despite the cylinders being in a side-by-side configuration.
Nanochannel geometry-depended behaviors on ion selectivity for salinity gradient energy harvesting
Authors: Ma Junhao , Liu Lang , Liu Chao , Jia Xuhong
Published: December 2024

Nanofluidic osmotic energy, which can be directly converted into electricity, is considered a clean and sustainable energy that effectively utilizes salinity gradients. The rational construction of nanochannel is of great significance to ion transport and osmotic energy conversion, but there is currently little attention paid to naturally formed rough and irregular channels. In this study, a model that considers the effects of nanochannel cone angle and waveform surface on interface reaction coupling was established for osmotic energy conversion. The results indicate that cone angle and waveform have a significant effect on osmotic energy conversion. It is found that the reduction of cone angle and the addition of waveform will improve ion selectivity and increase energy conversion efficiency, and ion rectification effect of corrugated cylindrical channel is the most obvious. Meanwhile, enlarging waveform dimensions leads to a significant overlap of electric double layer, resulting in a growth in cation transference number and selectivity, thereby enhancing the system's energy conversion efficiency, which can reach 49.62%. At low concentration ratios, the waveform dimensions are inversely proportional to the maximum output power, whereas at high concentration ratios, increasing the waveform dimensions and applying the waveform at channel entrance can efficiently improve the maximum output power.
Theme as point of departure in English and Spanish academic writing and casual conversation
Authors: Arús-Hita Jorge
Published: December 2024

This paper describes and compares the realisations, functions and interrelations of Theme as point of departure (POD), i.e. Theme stripped of any reference to “what the clause is about”, in two languages — English and Spanish — and two genres — academic writing and casual conversation. The ultimate goal is to find out which POD characteristics are (a) generalisable across both genres and both languages; (b) generalisable across both genres (but language-dependent); (c) generalisable across both languages (but genre-specific); and (d) genre-specific and language-specific. Among other things, the contrastive analysis reveals that POD is highly determined by metafunctional interplay, PODs in casual conversation reflecting the interpersonally-driven nature of this genre and cross-linguistic contrasts reflecting different pressures of interpersonal meaning on textual organisation.
The environment of quoting in Arabic
Authors: Bardi Mohamed Ali
Published: December 2024

When we use language, we normally do not engage in verbal interactions in isolation. So, when studying verbal
exchange, one should expect other activities to be manifested in some ways in the lexicogrammar either at clause simplex or clause
complex level. This article is a link in a chain of articles that set out to investigate different aspects of projection across a
variety of languages. It studies the verbal environment in which verbal projection occurs. It mainly explores explicit and
implicit quoting and reporting strategies and the activities that accompany quoting. It compares some characteristics identified
by Matthiessen and Teruya (2014a) in their investigation of quoting strategies in
English to those that appear in the environment of quoting in Arabic, in addition to exploring some other traits that are proper
to the quoting environment in Arabic.
The role of registerial expertise in texture re-creation in medical translation
Authors: Yue Yan , Fang Jing
Published: December 2024

This article investigates how an important aspect of translators’ registerial expertise — domain-specific
(medical) training and experience — may have consequences for the texture of a specialised translation, i.e. the translations of
the Chinese medicine classic Huang Di Nei Jing. Through a fine-grained analysis of cohesion and coherence, this
study demonstrates that a translator with a higher level of domain-specific expertise tends to produce a translation (i) that is
more lexically explicit and cohesively harmonious, (ii) with a richer semantic variety, more extended cohesive chains and
cross-chain interactions and (iii) having a higher degree of definitiveness. The findings suggest that a translator’s
domain-specific expertise could have measurable consequences for the texture of the target text.
To die is ‘to run (away)’
Authors: Ginevra Riccardo
Published: December 2024

Proto-Germanic *daw-ja-, the ultimate source of English to die, is here argued to have originally been a polysemous verb meaning ‘to run; to die’, corroborating its current etymological analysis as a reflex of the Proto-Indo-European root *dheu̯- ‘to run’. The proposal is supported by both well-known and previously unnoticed reflexes of the verb *daw-ja-in Gothic, Old Icelandic, and Old English, as well as by further Germanic lexical items and figurative expressions. Further support is provided by a series of semantic parallels in several Indo-European traditions, which, together with the Germanic material, reflect a well-known conceptual metaphor rooted in universal human cognition.
On the periodisation of early North Germanic
Authors: Schalin Johan
Published: December 2024

This article welcomes the recent proposal of Michael Schulte (2024) for a periodisation of early North Germanic, while pointing out problematic premises and criteria for the delimitation of the proposed subperiods. It is argued that in delimiting linguistic periods there is more to gain than lose for the clarity of scholarly argument if preference is given to linguistic rather than graphemic or socio-cultural criteria, even if it means that reconstructed, rather than ambiguously attested features, are given preference. The relevant chapter of a recent book by Nelson Goering (2023) is also reviewed to cast light on the syncope era. Elements and insights are proposed for a periodisation and labelling of early North Germanic suited for discussion on diachronic structural change.
Bridging the gap between tumor and disease: Innovating cancer and glioma models
Authors: Cirigliano Stefano M. , Fine Howard A.
Published: December 2024

Recent advances in cancer biology and therapeutics have underscored the importance of preclinical models in understanding and treating cancer. Nevertheless, current models often fail to capture the complexity and patient-specific nature of human tumors, particularly gliomas. This review examines the strengths and weaknesses of such models, highlighting the need for a new generation of models. Emphasizing the critical role of the tumor microenvironment, tumor, and patient heterogeneity, we propose integrating our advanced understanding of glioma biology with innovative bioengineering and AI technologies to create more clinically relevant, patient-specific models. These innovations are essential for improving therapeutic development and patient outcomes.
Newton’s electromagnetic bucket
Authors: Castaño D J , Cornwall J , Georg A
Published: December 2024

We explore the matter of Newton’s Bucket. To simplify and extend the analysis, we replace the bucket with an infinite cylindrical shell. We show that Newton’s mechanical conclusions are equally valid electromagnetically.
On direct and inverse obstacle scattering problems for biharmonic waves
Authors: Guo Jun , Long Yin , Wu Qinghua , Li Jin
Published: December 2024

In this paper the direct and inverse scattering problems for impenetrable obstacles in an infinite elastic Kirchhoff–Love two-dimensional plate are considered. By factoring the biharmonic operator, the displacement can be modeled by the Helmholtz equation and anti-Helmholtz equation with coupled boundary conditions. The well-posedness of the direct problem is proved by using a variational approach. The inverse problem consists of recovering the obstacle from the far field pattern of the scattered field at fixed wave number. The theoretical foundation of the linear sampling method is established. Numerical experiments show that the proposed method is feasible and effective.
Microfluidics in cardiac microphysiological systems: a review
Authors: Park Jiyoon , Zhang John X J
Published: December 2024

Inspired by the advances in microfabrication of microelectromechanical systems (MEMSs), microphysiological systems (MPSs) capitalized on the fabrication techniques of MEMS technology and pivoted to biomedical applications with select biomaterials and design principles. With the new initiative to refute animal testing and develop valid and reliable alternatives, MPS platforms are in greater demand than ever. This paper will first present the major types of MPSs in the cardiovascular research space, and then review the core design principles of such systems to closely replicate the in vivo physiology. Fabrication methodologies of the platform, as well as technologies that enable patterning and functionalizing scaffolds, and the various sensing modalities that can interface with such MPS platforms, are reviewed and discussed. This review aims to provide a comprehensive picture of cardiac MPSs in which microfluidics play an important role in the design, fabrication, and sensing modalities, and prospects of how this platform can continue to drive further improvements in cardiovascular research and medicine.
R-matrix analysis of 22Ne(α, n)25Mg and 22Ne(α, γ)26Mg reactions
Authors: Santra Rajkumar , Roy Subinit , Ali Sk Mustak
Published: December 2024

The reaction rates of 22Ne(α, n)25Mg and its competing channel 22Ne(α, γ)26Mg control the production of neutron flux for weak s-process nucleosynthesis in low mass asymptotic giant branch stars and in massive stars with M ≥ 10M
⊙. The temperature range of interest for these reactions lies between 0.2 and 0.4 GK. However, the rates of these reactions are poorly constrained at these temperatures due to uncertainties in the nuclear properties of several resonance states in the compound nucleus 26Mg, lying within the Gamow window. The present work reports a full R-matrix evaluation of the 22Ne(α, n)25Mg and 22Ne(α, γ)26Mg reaction rates using updated nuclear data of 26Mg states. Previous rate evaluation by Adsley et al and R-matrix calculations of Wiescher et al were limited by using narrow resonance approximations and omission of the resonances below E

r
= 705 keV, respectively. In this work, the R-matrix fit to the available 22Ne(α, n)25Mg reaction data is performed by including the contributions of previously neglected resonances below E

r
= 705 keV and considering the interference effects. The (α, n) reaction rate from the present R-matrix evaluations is noticeably higher than the narrow resonance approximation calculations in the temperature range 0.1−0.3 GK. In particular, the present (α, n) reaction rate is significantly higher (7.5 − 4.5 times) compared to Adsley et al at 0.2−0.3 GK and ≈2 times greater than Wiescher et al at 0.3 GK. The estimated reaction rate ratio of (α, n) to (α, γ) in the relevant temperature window 0.2−0.8 GK indicates that the production of neutrons for the s-process is more likely than the radiative alpha capture reaction, compared to the previous estimate by Adsley et al.
A planar capacitive sensor for detecting and measuring thickness and depth of oil under ice
Authors: Altrabolsi Mahmoud , Saleh Mahdi , Elhajj Imad H , Asmar Daniel
Published: December 2024

Detecting and characterizing oil spills in arctic environments is challenging due to the presence of sea ice. Methods based on ground-penetrating radars and acoustic sensors were used in the literature to detect oil in ice-covered waters; however, their implementation is costly, and their capabilities are limited in terms of oil-thickness estimation. To address this problem, we propose a new low-cost sensing system based on a planar capacitive sensor that can detect the presence of oil under ice sheets and measure its thickness and depth. Our proposed sensor is based on movable dual electrodes mounted next to each other on the same sensing plane. The electric field created between the electrodes extends beneath the sensing plane and is affected by the electric properties of the sensed material (ice, oil, or water). Changes in the mutual capacitance of the electrodes are related to changes in the thickness and depth of the embedded oil phase. The capacitance of the sensor is measured at two different excitation frequencies while changing the horizontal separation distance between the electrodes. These measurements are collected to create a dataset for training machine-learning-based classification and regression models to detect the presence of oil and measure its thickness and depth. In comparison with the available sensing techniques, our proposed sensor has several advantages, such as being non-invasive or non-intrusive, simple to manufacture, safe to operate, and having low cost and low maintenance requirements. The experimental evaluation described in this paper demonstrates the effectiveness of our proposed system, which showed a very high detection accuracy of more than 90% and an accurate thickness and depth estimation capability with a mean absolute error of around 0.5 cm for thickness and depth estimations for oil thicknesses ranging between 0.5 cm and 8 cm and for oil depths ranging between 2 and 5 cm.
A demonstration experiment to study the properties of standing electromagnetic waves
Authors: Grebenev I V , Kazarin P V
Published: December 2024

A variant of studying the properties of electromagnetic waves during a lecture demonstration using a Seibt coil is proposed. The article describes the physical foundations necessary to understand the demonstrations and the technical details of the demonstration setup used. Particular attention is paid to the organization of educational activities of students to assimilate the properties of standing electromagnetic waves on the basis of the proposed version of the experimental setup. Since this topic is little covered in the literature available to teachers, the article is offered as a teaching-learning material for teachers of general physics in the study of standing electromagnetic waves. Our experience in using the described demonstration shows a statistically significant increase in the level of assimilation of the properties of the topic under study at the levels of both reproduction and application of the content.
Simple demonstration experiments to promote deeper learning and eliminate students’ misconception about light transmission phenomenon
Authors: Kumar Arvind , Hussain Sujat , Kumar Mukesh , Kumar Sanjeev
Published: December 2024

Experiments that illustrate physics principles or phenomena through real-world examples not only foster scientific thinking skills but are also effective to understand the underlying science and pique students’ interest. In this paper, we report very simple and novel demonstration experiments to understand the difference between direct (or specular) and diffuse transmission of light using plain and chemically etched glass slides. The present demonstration experiments effectively elucidate an important optical property known as transmission haze, which occurs as a result of light scattering. Furthermore, these demonstrations are particularly useful in recognizing and correcting students’ misconception that light absorption causes the object to appear fuzzy and blurry (translucency) when viewed through textured or frosted glass. These low-cost demonstrations teach students about the technological significance of high- and low-haze transmission as well.
Experimental learning on plant-leaf anatomy through electrical conductivity: a multidisciplinary educational inquiry into bio-batteries
Authors: Srivastava Vinit , Sharma Radhika , Vaish Rahul
Published: December 2024

This study investigates the electrical conductivity of plant materials as a multidisciplinary educational tool, focusing on the potential of bio-batteries derived from fruits and vegetables. By examining the midrib, veins, lamina, and petiole of radish leaves, the research uncovers key relationships between leaf morphology, nutrient distribution, and electrical resistance. Experimental results reveal an inverse correlation between electrode distance and conductivity, with resistance values increasing from 17 kΩ at 1 cm to 120 kΩ at 6 cm along the midrib. Similar trends were observed in fruits and vegetables, where electrical resistance ranged from 15 Ω (onion) to 150 Ω (ladyfinger). Open circuit voltage measurements highlight significant variation, with Indian gooseberry achieving 0.966 V, onion 0.8 V, and lemon 0.9 V. Compact slices (2 cm × 1 cm × 0.5 cm) of onion stacked in series produced a cumulative output of 3.2 V, sustaining LED illumination for one hour.
The impact of remote labs on acquiring significant learning in engineering students
Authors: Ramírez Antonio , Villamagua Luis , Rivera Richard , Guerrero Reinaldo , Sánchez-Herrera Reyes , Ginestar Damián , Riera Jaime
Published: December 2024

In this article, we utilized an experimental and cross-sectional approach to assess the evolution and learning impact of remote labs on the acquisition of meaningful knowledge by engineering students. To accomplish this objective, we automated a device capable of replicating the phenomenon of motion on an inclined plane and incorporated additional features to enable remote control, granting students access to the apparatus. Data for the statistical analysis was collected from a sample of 78 engineering students with similar educational levels and experience, who participated in four stages of the process. Statistical analysis performed through Friedman test strongly points to a positive influence of the remote laboratory in the learning process, in contrast to the use of a traditional one and the conventional theoretical induction. It is important to notice that, in both tests, the significance was less than 0.001, which strongly supports the findings. Satisfaction surveys were applied to the students, whose results showed a high reliability thanks to a Cronbach´s alpha coefficient of 0.9. These results highlight the positive perception of the students about the remote laboratory, compared to other learning models. Moreover, participants were highly satisfied with the integrated pedagogical tool in the class curriculum, valuing its robustness, ease of access, real-time control over main parameters, and user-friendly interface, which facilitated obtaining first-hand experimental data.
Empirical correction decomposition method (ECDM): enhancing accuracy of quantitative measurement in spectral CT
Authors: Wang Chengmin , Wang Zhe , Li Mohan , Liu Yuedong , Zhang Xiaomei , Wei Cunfeng , Wei Long
Published: December 2024

Objective. Spectral CT and material decomposition methods are crucial for precise material identification and quantitative composition analysis in preclinical research and clinical diagnosis. The empirical material decomposition method is widely used for its straightforward modeling approach, independence from spectral and detector response knowledge, and operational convenience. However, this method has limited decomposition accuracy and its precision depends on the choice of calibration phantoms. Approach. To address these issues, we propose an empirical correction decomposition method (ECDM). The innovation of this method lies in its ability to conveniently estimate and correct empirical decomposition errors using a specially designed calibration phantom. First, the specially designed calibration phantom for ECDM undergoes empirical decomposition initially to establish the relationship between decomposition errors and decomposition values. Then, ECDM estimates and corrects the error of empirical decomposition values. Main results. In the phantom experiments, ECDM improves the decomposition accuracy of empirical methods, effectively reducing the different decomposition errors caused by four different sizes of calibration phantoms from a maximum of 144% to within 25%. In the mouse experiments, ECDM achieves accurate quantification of contrast agents in biological tissues, outperforming the other two methods. The absolute error percentages of ECDM in the decomposition results of the two standard iodine solutions are both less than 5%. Significance. ECDM significantly improves decomposition accuracy and reduces the impact of the size of the empirical calibration phantom. Overall, our method based on spectral CT is very convenient and practical for the quantitative measurement in biomedical applications.
Whispering gallery mode optical resonators for biological and chemical detection: current practices, future perspectives, and challenges
Authors: Hao Shuang , Su Judith
Published: December 2024

Sensors are important for a wide variety of applications include medical diagnostics and environmental monitoring. Due to their long photon confinement times, whispering gallery mode (WGM) sensors are among the most sensitive sensors currently in existence. We briefly discuss what are WGM sensors, the principles of WGM sensing, and the history of the field, beginning with Mie theory. We discuss recent work in the field on using these WGM resonators as sensors, focusing particularly on biological and chemical sensing applications. We discuss how sensorgrams are acquired and fundamental measurement limits. In addition, we discuss how to interpret binding curves and extract physical parameters such as binding affinity constants. We discuss the controversy surrounding single-molecule detection and discuss hybrid WGM nanoparticle sensors. In addition, we place these sensors in context with others sensing technologies both labeled and label-free. Finally, we discuss what we believe are the most promising applications for these devices, outline remaining challenges, and provide an outlook for the future.
Regulable energy valves for energy harvesting by screw-nut structures
Authors: Li J R , Guo J C , Zhao J , Zhang Z
Published: December 2024

Piezoelectric energy harvesting (EH) is very important for environment protection. Here we developed a novel regulable phononic crystals (PnCs) featuring screw-nut structures as an energy valve for EH in wave transmission environment. It is fabricated by additive manufacturing for experimental tests. By regulating the nut of the designed PnCs, the peak output voltage and output electric power of the EH system can be varied in the range of 0.066–2.15 times and 0.004–4.63 times, respectively, compared to the unregulated PnCs. The output performance of the EH system increases as the screw-nut structure is screwed out by guiding the wave transmission, localizing more energy at the defect. The output performance of the EH system significant decrease due to the regulated nut near the defect disrupts the periodicity of the PnCs, preventing the formation of band gap and defect band. Experimental results corroborate the numerical simulations, validating the feasibility of employing screw-nut structures to manipulate output performance. This study offers a regulable solution for adaptive EH systems being capable of responding to varying environmental conditions and energy demands, and provides valuable insights for the design of self-powered devices.
Uncertainty and worst-case expectation analysis for multiphysics QPR simulations
Authors: Putek Piotr , Adrian Simon B , Wenskat Marc , van Rienen Ursula
Published: December 2024

Quadrupole resonators (QPRs) serve to characterize superconducting samples. Like any cavity, during operation, they will deviate from the design geometry for various reasons. Those deviations can be static, stemming from manufacturing variations reflected in the manufacturing tolerances, or dynamic, such as electromagnetic radiation pressure (Lorentz detuning) or microphonics. As a result, a QPR’s measurement accuracy and general operation can be severely limited. In particular, during operation, it became evident that the third operating mode of typical QPRs is mainly affected. In this work, by solving the underlying multiphysics problem with random input parameters, we predict the predominant sources of significant measurement bias in surface resistance. On the one hand, we employ the stochastic collocation method compound with the polynomial chaos expansion (PC-SCM) to quantify uncertainties in the physical model governed by a coupled electro-stress-heat problem. On the other hand, we explore the perturbation analysis to calculate the mean-worst-scenario bound of the merit functions due to the first-order truncation of the Taylor expansion around mean parameter values. The developed method allows us to study the effect of a small nonlinear deformation on the performance of the QPR. Finally, we discuss the simulation results and their implication for the operational conditions of the QPRs.
Particles depositions onto non-smooth surfaces of ventilation ducts
Authors: Orabi M
Published: December 2024

In a previous paper, a model was established to account for particles’ deposition onto the inner surfaces of small spaces. In that paper, only smooth surfaces were considered. A modification of that model is proposed here in this article to provide a description for non-smooth (rough) surfaces. This is attained by altering the limits of the boundary-layer that are used to do the integrations required to calculate the deposition speeds. To apply the model, deposition of particles onto the inner rough surfaces of a ventilation-duct is considered, as an example. Deposition speeds onto the walls, floor and ceiling of the duct are estimated with comparing them to the experimental-data. By considering different values of the friction velocities, the alterations of the lower-limit in the boundary-layer are mathematically related to the corresponding friction velocities. The proposed model has the advantage of predicting the alteration in the limits of the boundary-layer, once the friction-velocity is provided. This is very important as the friction-velocity is a key parameter used in the descriptions of particles’ deposition and penetration.
Bent zigzag graphene nanoribbons for spintronic applications
Authors: Farghadan Rouhollah
Published: December 2024

We investigate a spintronic device utilizing bent zigzag graphene nanoribbons (ZGNRs) to explore their spin-dependent electronic and transport properties. Employing a mean-field Hubbard model and the Landauer-Büttiker formalism, we examine the effects of curvature on a large-scale bent ZGNR, revealing a spin-semiconducting phase in the antiferromagnetic ground state. The device comprises a circularly curved nanoribbon connected to two straight ZGNRs, forming a two-terminal, stretchable system. Our findings demonstrate that the spin energy gap and spin-splitting effects in bent ZGNRs are highly tunable via curvature parameters-total rotation, radius, and width. Even minimal curvature induces significant spin-dependent behavior and spin Seebeck coefficient (SSC), resulting in full spin polarization in both the density of states and the transmission coefficient. The degree of spin polarization increases with the bending parameter, leading to enhanced spin-polarized current and a substantial SSC. These results suggest that bent ZGNRs are promising for advancing spintronic applications, particularly in flexible device technologies.
Improved photocatalytic degradation of methylene blue and rhodamine G dye under UV-radiation by rGO-MoO3
Authors: Ushal Ruhinaz , Ahmed Bilal , Singh Arvind , Ojha Animesh Kumar
Published: December 2024

In this work, we report facile synthesis of rGO-MoO3 nanocomposites as photocatalysts via one-step hydrothermal method. Initially, the synthesized materials were characterized by different physicochemical methods to reveal the structural, morphological, optical, and other properties. The transmission electron microscopy (TEM) and Raman spectroscopy results validate the formation of rGO-MoO3 nanocomposites. The optical bandgap values of pristine MoO3 (3.47 eV) and rGO-MoO3 (3.36 eV), reveal that they can serve as ultra-violet light photocatalysts, for the decomposition of organic pollutants e.g. methylene blue (MB) and rhodamine G (RhG) dye. The rGO-MoO3 nanocomposites significantly enhanced the photodegradation efficiency as compared to MoO3, due to the interfacial interaction between the composite parts and promoted the transfer of charge carriers from MoO3 to rGO, causing a reduced rate of electron-hole recombination. The highest degradation efficiency was observed for rGO-MoO3 nanocomposite {for MB (∼50%) and RhG (∼96%)}, whereas for MoO3 {for MB (∼40%) and RhG (∼43%)}. This report highlights a noteworthy impact of rGO with MoO3 nanocomposites as a photocatalyst.