bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of novel organic polar materials: A machine learning study with importance sampling
Authors: Ghosh Ayana , Trujillo Dennis P. , Hazarika Subhashis , Schiesser Elizabeth , Swamynathan M. J. , Ghosh Saurabh , Zhu Jian-Xin , Nakhmanson Serge
Published: December 2023

Recent advances in the synthesis of polar molecular materials have produced practical alternatives to ferroelectric ceramics, opening up exciting new avenues for their incorporation into modern electronic devices. However, in order to realize the full potential of polar polymer and molecular crystals for modern technological applications, it is paramount to assemble and evaluate all the available data for such compounds, identifying descriptors that could be associated with an emergence of ferroelectricity. In this paper, we utilized data-driven approaches to judiciously shortlist candidate materials from a wide chemical space that could possess ferroelectric functionalities. A machine learning study with importance sampling was employed to address the challenge of having a limited amount of available data on already-known organic ferroelectrics. Sets of molecular- and crystal-level descriptors were combined with a Random Forest Regression algorithm in order to predict the spontaneous polarization of the shortlisted compounds. First-principles simulations were performed to further validate the predictions obtained from the machine learning model.
Attention hybrid variational net for accelerated MRI reconstruction
Authors: Shen Guoyao , Hao Boran , Li Mengyu , Farris Chad W. , Paschalidis Ioannis Ch. , Anderson Stephan W. , Zhang Xin
Published: December 2023

The application of compressed sensing (CS)-enabled data reconstruction for accelerating magnetic resonance imaging (MRI) remains a challenging problem. This is due to the fact that the information lost in k-space from the acceleration mask makes it difficult to reconstruct an image similar to the quality of a fully sampled image. Multiple deep learning-based structures have been proposed for MRI reconstruction using CS, in both the k-space and image domains, and using unrolled optimization methods. However, the drawback of these structures is that they are not fully utilizing the information from both domains (k-space and image). Herein, we propose a deep learning-based attention hybrid variational network that performs learning in both the k-space and image domains. We evaluate our method on a well-known open-source MRI dataset (652 brain cases and 1172 knee cases) and a clinical MRI dataset of 243 patients diagnosed with strokes from our institution to demonstrate the performance of our network. Our model achieves an overall peak signal-to-noise ratio/structural similarity of 40.92 ± 0.29/0.9577 ± 0.0025 (fourfold) and 37.03 ± 0.25/0.9365 ± 0.0029 (eightfold) for the brain dataset, 31.09 ± 0.25/0.6901 ± 0.0094 (fourfold) and 29.49 ± 0.22/0.6197 ± 0.0106 (eightfold) for the knee dataset, and 36.32 ± 0.16/0.9199 ± 0.0029 (20-fold) and 33.70 ± 0.15/0.8882 ± 0.0035 (30-fold) for the stroke dataset. In addition to quantitative evaluation, we undertook a blinded comparison of image quality across networks performed by a subspecialty trained radiologist. Overall, we demonstrate that our network achieves a superior performance among others under multiple reconstruction tasks.
Probing chiral discrimination in biological systems using atomic force microscopy: The role of van der Waals and exchange interactions
Authors: Kapon Yael , Zhu Qirong , Yochelis Shira , Naaman Ron , Gutierrez Rafael , Cuniberti Giannaurelio , Paltiel Yossi , Mujica Vladimiro
Published: December 2023

We analyze from a theoretical perspective recent experiments where chiral discrimination in biological systems was established using Atomic Force Microscopy (AFM). Even though intermolecular forces involved in AFM measurements have different origins, i.e., electrostatic, bonding, exchange, and multipole interactions, the key molecular forces involved in enantiospecific biorecognition are electronic spin exchange and van der Waals (vdW) dispersion forces, which are sensitive to spin–orbit interaction (SOI) and space-inversion symmetry breaking in chiral molecules. The vdW contribution to chiral discrimination emerges from the inclusion of SOI and spin fluctuations due to the chiral-induced selectivity effect, a result we have recently demonstrated theoretically. Considering these two enantiospecific contributions, we show that the AFM results regarding chiral recognition can be understood in terms of a simple physical model that describes the different adhesion forces associated with different electron spin polarization generated in the (DD), (LL), and (DL) enantiomeric pairs, as arising from the spin part of the exchange and vdW contributions. The model can successfully produce physically reasonable parameters accounting for the vdW and exchange interaction strength, accounting for the chiral discrimination effect. This fact has profound implications in biorecognition where the relevant intermolecular interactions in the intermediate-distance regime are clearly connected to vdW forces.
Demonstration of a facile and efficient strategy for yield stress determination in large amplitude oscillatory shear: Algebraic stress bifurcation
Authors: Wang Pengguang , Xu Jiatong , Zhang Hongbin
Published: December 2023

The large amplitude oscillatory shear (LAOS) has been extensively studied for understanding the rheological responses of yield stress fluids. However, the employed methodology for determining the yield stress remains uncertain albeit the fact that many classical or plausible methods exist in the literature. Along these lines, herein, based on Fourier transform (FT) rheology, stress decomposition, and stress bifurcation, a new straightforward method termed as algebraic stress bifurcation was developed. More specifically, the main goal was to determine the yield stress and investigate the solid–liquid transition of fluids in LAOS. A simple and efficient mathematical framework was established and verified by the KVHB, Saramito, Giesekus models, and FT rheology. The main strength of this approach is that only the data from the stress/strain sweep are required instead of Lissajous curves. Alternative curves based on the first harmonic were constructed to demonstrate the non-critical role of both higher harmonics and phenomenological Lissajous curves in determining yield stress. The determined start and end yield points in the solid–liquid transition were compared with the already existing methods. Furthermore, the resulting solid–liquid transition region was analyzed by FT rheology, stress decomposition, and sequence of the physical process to obtain information on nonlinearity and intracycle/intercycle yielding. Our work provides fruitful insights for explaining and reducing the complexities of the stress bifurcation technique by using an easy-to-understand and implement format. Therefore, a concise theoretical framework was introduced for understanding the concept of yield stress, the intercycle yielding process, and the rational choice of yield stress measurement techniques.
Effects of activation energy on irregular detonation structures in supersonic flow
Authors: Cai Xiaodong , Xu Fei , Deiterding Ralf , Chen Weiqiang , Liang Jianhan
Published: December 2023

In this work, high-precision numerical simulations of detonations in supersonic hydrogen–oxygen premixed gases with different activation energies are carried out. The open-source program Adaptive Mesh Refinement in Object-Oriented C++ is adopted, and the monotone upstream–centered scheme for conservation laws total variation diminishing numerical scheme is utilized to solve the Euler equations coupled with a one-step, two-component reaction model. The wave structure characteristics of the irregular cellular detonation process are obtained, and its initiation and propagation characteristics under different activation energies are analyzed in depth. The results show that, unlike a regular detonation wave structure, the Mach stem of an irregular detonation wave is prone to bifurcation in a supersonic mixture with high activation energy. In addition to the incident shock wave and the Mach stem structure, a hybrid shock wave structure also appears between the two due to the random generation of weak triple points. Moreover, the leading shock wave intensity of the irregular detonation weakens, resulting in the generation of many unburned jets whose sizes and shapes depend on the triple point type. Although the oscillation amplitude of the irregular detonation is large and its regularity is weak, the detonation wave can achieve approximate dynamic stability in the channel.
Design approach of thrust-matched rotor for basin model tests of floating straight-bladed vertical axis wind turbines
Authors: Cao Q. , Chen Y. , Zhang K. , Zhang X. , Cheng Z. , Wen B.
Published: December 2023

Rotor redesign approaches have been widely proposed to solve the thrust mismatch issue caused by scaling effects for basin model tests of horizontal axis floating wind turbines (FWTs). However, limited basin model tests utilized the thrust-matched rotor (TMR) to accurately evaluate the aerodynamic loads applying to the vertical axis FWTs. This paper described the detailed design approach of the TMR of floating straight-bladed vertical axis wind turbines (VAWTs) with a rated power of 5.3 MW. First, the AG455 airfoil was selected to replace the NACA0018 airfoil. AG455 airfoil can show a larger lift coefficient and a smaller drag coefficient at low Reynolds number. On this basis, the load distribution match algorithm was used to assign the blade pitch angle and chord length at each section of the blade. This method takes the spanwise load and load change rate of model-scaled blade and full-scaled blade as the constraint conditions. By adopting this method, the rotor thrust can be tailored to match the prototype values across a wide range of tip speed ratios. This design approach proves advantageous in assessing the aerodynamic performance of VAWTs under varying inflow wind speeds and unsteady wind conditions. The redesigned TMR model under low Reynolds number can meet Froude similarity criterion, which is helpful to improve the accuracy of vertical axis FWT model tests in the wave basin.
Investigation on spontaneous liquid–liquid imbibition in capillaries with varying axial geometries using lattice Boltzmann method
Authors: Zhang Shengting , Li Jing , Chen Zhangxin , Wu Keliu , Zhu Qingyuan
Published: December 2023

Spontaneous liquid–liquid imbibition in capillaries with irregular axial geometries is common in the petroleum industry. Monitoring the real-time dynamic contact angle (DCA) of the meniscus is crucial during such processes. In this work, we extend the Bell–Cameron–Lucas–Washburn (BCLW) equation by considering the axial shape of the capillaries, inertial force, and non-wetting fluid viscosity. We also develop a cascaded multi-component Shan–Chen lattice Boltzmann method (CLBM) with a modified mass-conservative curved boundary scheme to accurately simulate imbibition processes in sinusoidal capillaries. The results indicate that the DCA is highly sensitive to variations in the axial geometry of the capillary during imbibition, displaying a periodic time evolution pattern. When the axial geometry diverges, the DCA increases, and when it converges, the DCA decreases. The viscosity ratio affects the imbibition velocity, controlling the evolution period and extreme values of the DCA. A critical contact angle exists for a fixed capillary axial geometry and viscosity ratio. Continuous spontaneous imbibition occurs if the static contact angle is smaller than this critical value. However, if it exceeds this threshold, imbibition ceases within regions where axial geometry divergence. Moreover, we noticed a discrepancy in imbibition lengths predicted by the extended BCLW equation that ignores the DCA compared to those computed through the CLBM. To address this issue, we employed CLBM to monitor the DCA in real time and used the gathered data to refine the extended BCLW equation. As a result, the prediction of imbibition lengths by the extended BCLW equation for coupling the DCA became more accurate.
Consistent energy-based framework of amplification mechanisms for the second mode in hypersonic boundary layers
Authors: Chen Yifeng , Guo Peixu , Wen Chihyung
Published: December 2023

The second mode is of general interest in hypersonic boundary layer flows due to its underlying responsibilities for transition to turbulence. However, a long-term debate exists on the detailed energy sources that sustain the modal exponential growth. Currently, three influential energy-based approaches appear to show different significant energy sources due to dissimilar mathematical formulations, including the momentum potential theory, the inviscid Lagrangian energy analysis, and the relative phase analysis. In this study, these three fundamental approaches are employed and examined in conjunction with direct numerical simulations. The purpose is to seek a possible unified explanation of the source terms that dominate the exponential evolution of the second mode. In the considered Mach 6 flow state, all three approaches consistently point to the same local energy amplification route driven by two pronounced source terms: the dilatation term in the near-wall region and the Reynolds thermal stress term or heat exchange term across the outer layer region, depending on the selection of the specific energy norm. The mathematical forms of the corresponding sources are derived or discussed explicitly. Theoretical and simulation results provide a unified understanding of the local energy amplification mechanisms of the second mode.
Solute imbibition in paper strip: Pore-scale insights into the concentration-dependent permeability
Authors: Behera Prateechee Padma , Mehta Sumit Kumar , Arun Ravi Kumar , Mondal Pranab Kumar
Published: December 2023

Capillary wicking in a thicker gel blot microfluidics paper has been investigated through a combination of an analytical framework, experiments, and numerical simulations. The primary objectives of this work are to investigate the concentration-dependent wicking process inside thicker microfluidic paper and to estimate the concentration-dependent permeability using both theoretical models and experimental data. An additional goal is to estimate the parameters for saturation-dependent flow modeling in thicker microfluidic paper. To comprehend the wicking phenomenon on thicker gel blot paper, a series of experiments employing aqueous food dye solutions at varying concentrations has been conducted. In order to calculate the temporal wicking length analytically, the Brinkman-extended Darcy equation is implemented. By modifying the permeability expression for a simple rectangular unidirectional fiber cell and pure liquid, the expression of effective permeability for the analytical framework has also been introduced. The concentrations of the food dye solutions appear to have a substantial influence on the wicking phenomenon. Effective permeability and wicking length have been found to follow a decreasing pattern at lower concentrations while both increase at higher values. Intriguingly, employing a microfluidics paper with a relatively greater thickness facilitates the visualization of the fluid front. This phenomenon is identified by the formation of an acute angle at intermediate time instants, while the fluid front angle assumes an angle nearly ∼90° during smaller and higher time instants. In order to evaluate the saturation-dependent capillary pressure and permeability, the empirical correlation of concentration-dependent Brooks and Corey parameters is additionally determined experimentally. These parameters are subsequently employed in numerical simulations to illustrate the saturation-dependent flow field using Richards’ equation. Furthermore, numerical simulations based on these estimated model parameters have been conducted, and it turns out that the saturation field has an excellent agreement with the experimental results. The results of the current study can be used to design low-cost paper-based diagnostic devices for usage in healthcare and environmental applications.
Architectural control over morphologies of bottlebrush block copolymer superstructures
Authors: Mikhailov Ivan V. , Zhulina Ekaterina B. , Borisov Oleg V. , Nardin Corinne , Darinskii Anatoly A.
Published: December 2023

The morphology of superstructures formed by bottlebrush block copolymers in the melt can be tuned by changing the side chain length or/and their grafting density at constant volume fractions of the blocks. This feature enables fabrication of microphase separated bulk structures and mesoporous materials thereof with spherical or cylindrical domains (precursors of the mesopores), with high porosity unattainable for materials produced from conventional linear block copolymers. These paradigms are proven by DPD simulations that allow constructing morphological phase diagrams of the melt of block copolymers comprising one linear and one bottlebrush block and comparing the simulation results to the predictions of the mean field analytical theory. While the binodal lines separating the stability regions of spherical and cylindrical domains predicted by the theory perfectly match the simulation results, the simulation indicates appearance of a gyroid phase around the theoretical binodal separating the stability ranges of cylinders and lamellae. The results of our work provide guidelines for macromolecular design of novel composite and mesoporous materials with a wide spectrum of potential applications.
Metastable Co3Mn/Fe/Pb(Mg1/3Nb2/3)O3–PbTiO3 multiferroic heterostructures
Authors: Murakami Y. , Usami T. , Watarai R. , Shiratsuchi Y. , Kanashima T. , Nakatani R. , Gohda Y. , Hamaya K.
Published: December 2023

Using a molecular beam epitaxy technique, we experimentally demonstrate a multiferroic heterostructure consisting of metastable ferromagnetic Co3Mn on piezoelectric Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMN-PT). Inserting a 2-nm-thick Fe layer between Co3Mn and PMN-PT(001) allows the formation of bcc Co3Mn layers even at an extremely low growth temperature of ∼80°C. Upon increasing this temperature to 200 °C, a bcc Co3Mn/Fe/PMN-PT(001) multiferroic heterostructure with a relatively large saturation magnetization of ∼1680 kA/m and an atomically flat interface is obtained, resulting in an obvious converse magnetoelectric (CME) effect. The large CME effect originates mainly from the strain-induced modulation of the magnetic anisotropy energy, supported by the first-principles calculations.
Viscoelastic rheology of polymer solution probed by resonant thermal capillary fluctuation
Authors: Zhang Hao , Gorin Benjamin , Kellay Hamid , Maali Abdelhamid
Published: December 2023

We present a measurement of viscoelastic properties of polymer solutions using resonant thermal capillary fluctuations of the surface of a polymer solution droplet. The instantaneous deflection of a cantilever in contact with the drop surface allows for measuring the nanoscale thermal fluctuations of the interface. From the power spectral density of measured fluctuations, we determine the two components of the rheological (dynamic and elastic viscosity) response of the fluid. Our experimental results were compared with rheological measurements using a classical commercial rheometer. We find a good agreement between the two measurements. Our experiments allow to extend the range for dynamical measurements of rheological properties of the solutions up to 20 000 s−1. Furthermore, our method requires only a small volume of liquid (10 μl) to measure the viscosity and is thus suitable for measurements on precious liquids.
ALS-linked C9orf72–SMCR8 complex is a negative regulator of primary ciliogenesis
Authors: Tang Dan , Zheng Kaixuan , Zhu Jiangli , Jin Xi , Bao Hui , Jiang Lan , Li Huihui , Wang Yichang , Lu Ying , Liu Jiaming , Liu Hang , Tang Chengbing , Feng Shijian , Dong Xiuju , Xu Liangting , Yin Yike , Dang Shangyu , Wei Xiawei , Ren Haiyan , Dong Biao , Dai Lunzhi , Cheng Wei , Wan Meihua , Li Zhonghan , Chen Jing , Li Hong , Kong Eryan , Wang Kunjie , Lu Kefeng , Qi Shiqian
Published: December 2023

Massive GGGGCC (G4C2) repeat expansion inC9orf72and the resulting loss of C9orf72 function are the key features of ~50% of inherited amyotrophic lateral sclerosis and frontotemporal dementia cases. However, the biological function of C9orf72 remains unclear. We previously found that C9orf72 can form a stable GTPase activating protein (GAP) complex with SMCR8 (Smith-Magenis chromosome region 8). Herein, we report that the C9orf72–SMCR8 complex is a major negative regulator of primary ciliogenesis, abnormalities in which lead to ciliopathies. Mechanistically, the C9orf72–SMCR8 complex suppresses the primary cilium as a RAB8A GAP. Moreover, based on biochemical analysis, we found that C9orf72 is the RAB8A binding subunit and that SMCR8 is the GAP subunit in the complex. We further found that the C9orf72–SMCR8 complex suppressed the primary cilium in multiple tissues from mice, including but not limited to the brain, kidney, and spleen. Importantly, cells with C9orf72 or SMCR8 knocked out were more sensitive to hedgehog signaling. These results reveal the unexpected impact of C9orf72 on primary ciliogenesis and elucidate the pathogenesis of diseases caused by the loss of C9orf72 function.
From “Within” to “Beyond” in interpreting studies
Authors: Gu Chonglong , Wang Binhua
Published: December 2023

While there have been recent calls for an “outward turn” in (written) translation studies, interpreting
researchers have mostly taken an inward-looking view of interpreting and investigated it as a semi-closed system and an arguably
self-interested practice from within, despite the fact that interpreting in various forms and settings has been a co-constructing
factor in the transfer of knowledge and also a vital shaper of history, (geo)politics, culture, religion, communication, and our
human civilization. Going from “within” to “beyond,” this article conceptualizes interpreting as a consequential socio-political
and historical shaping force and a source of inter/trans-disciplinary conviviality and argues for an outward turn in interpreting
studies (IS). This article reviews pertinent recent studies with interdisciplinary and outward-looking features that have
endeavored to answer the important “so-what” question in IS. These studies highlight the vital role and far-reaching impact of
interpreting and interpreters in shaping different spheres of human communication and civilization across time and space. The
article also points out directions to move IS forward from a predominantly inward-looking practice. We argue that it is high time
we ventured out of our comfort zone, got off the well-trodden path, and took an outward-looking view of interpreting so that the
sub-discipline can have more meaningful and mutually enriching dialogues with other disciplines and subject areas.
On the dynamic interplay of macro and micro contexts in translation
Authors: Qiao Peng
Published: December 2023

This study explores the dynamic interplay between macro and micro contexts in Chinese fans’ translations of Cardi
B-related videos on Bilibili. Referring to the concept of translation as a cluster concept, Cardi B is considered as a dynamic
source cluster for interlingual and intersemiotic translations, leading to the evolving formulation of the micro context
surrounding the subtitled bullet-screen videos. Given the frequent changes in the micro context, two relatively stable components
of the macro context are initially identified for the navigation of the corresponding micro contextual elements. The macro context
includes the socio-political component of tensions in the China-United States relationship during the COVID-19 period of Trump’s
presidency, and the subcultural component of Bilibili as a carnival. By analysing the interaction between macro and micro contexts
within the target culture, as exemplified in the translator’s additions and target audiences’ on-screen danmu
comments, this study concludes that the macro and micro contexts are in dynamic interplay when the source cluster and the
translation workflow have an evolving nature. Moreover, the two contexts are no longer set at opposing ends of a spectrum.
Instead, an intermediate zone is bridged by danmu comments, blurring the boundaries between macro and micro
contexts in cyberspace.
Preventive behaviour and attitudes towards early childhood caries amongst mothers of toddlers in Bangladesh
Authors: Haque Farzana , Folayan Morenike O. , Virtanen Jorma I.
Published: December 2023

Background: Our aim was to analyse mothers of toddlers’ preventive behaviour towards ECC in Bangladesh.
Methods: We conducted a cross-sectional survey of mothers and their 6–24-month-old children visiting vaccination centres in Trishal, Bangladesh in 2021. A cluster-sampling method was applied to select 10 immunization centres and all mothers who attended the centres with a 6–24-month-old child were recruited. Mothers’ preventive behaviour and attitude towards oral health was determined using a reliable instrument. Clinical examinations were conducted to assess the presence of dental plaque on the labial surfaces of the upper central incisors and the ICDASII index criteria were utilized to detect ECC. The associations between preventive behaviours and the plaque score and caries status of the children were determined using multivariable logistic regression analysis after adjusting for confounding variables (mother’s age and educational status).
Results: The prevalence of ECC among the children was 25.8%. ECC experience was significantly associated with low educational level (p = 0.02) and older age (p = 0.01) of mothers. Of the mothers, 75.2% reported to brush their teeth twice daily and about half of them (48.8%) cleaned their children’s teeth daily; and 5.8% with fluoridated toothpaste. The multivariate logistic regression analysis showed that caries preventive behaviour of mothers (AOR = 2.63, 95% CI1.41–4.91) and the plaque score of the child (AOR = 14.69, 95% CI7.45–28.9) were significant risk indicators for ECC in the study population.
Conclusions: The prevalence of ECC was high among the Bangladeshi toddlers and factors such as the mothers’ preventive behaviour and presence of plaque were associated with the occurrence.
Geodetic precession and shadow of quantum extended black holes
Authors: Saadati Reza , Shojai Fatimah
Published: December 2023

We study the circular motion of massive and massless particles in a recently proposed quantum-corrected Schwarzschild black hole in loop quantum gravity. This solution is supposed to introduce small but non-zero quantum corrections in the low curvature limit. In this paper, we confine our attention to the shadow of the black hole and the geodetic precession (GP) of a freely falling gyroscope in a circular orbit. Despite the mathematical complexity of the metric, our results are exact and show that the black hole shadow decreases slightly in this solution while the quantum corrections introduce a non-trivial term in the GP frequency of the gyroscope.
A pedagogical approach to introducing the honeycomb lattice gauge theory
Authors: Huang Fei-Jie , Zhao Yi-Fen
Published: December 2023

A pedagogical approach to introducing the honeycomb lattice gauge theory is presented. Lattice gauge theory, which is an important theory for understanding strongly correlated systems, is a significant topic covered in the quantum field theory course for graduate students. Typically, quantum field theory textbooks introduce lattice gauge theory using the square lattice. However, beginners often find it challenging to grasp such an abstract theory only through the example of the square lattice. In this paper, we introduce lattice gauge theory using an alternative lattice—the honeycomb lattice. By comparing the differences between honeycomb and square lattice gauge theories, we highlight the fundamental principles of lattice gauge theory. This pedagogical approach will assist students in gaining a fresh perspective on grasping lattice gauge theory.
Modelling assisted tunneling on the Bloch sphere using the Quantum Composer
Authors: Bley Jonas , Mattei Vieri , Goorney Simon , Sherson Jacob , Heusler Stefan
Published: December 2023

The Bloch sphere representation is a geometric model for all possible quantum states of a two-level system that can be used to describe the time dynamics of a qubit. As explicit application, we consider the time dynamics of a particle in a double-well potential. In particular, we adopt a recent method for off-resonant excitations, the so-called SUPER principle (Swing Up of the quantum emitter population) driven by periodic electromagnetic fields, to the context of quantum tunnelling. We show that the tunnelling probability can be enhanced significantly when an appropriate oscillation of the potential height is introduced. Driven by a collaborative approach we call educator-developer dialogue, an updated version of the software Quantum Composer is presented. For educational purposes, we map the two lowest energy states of the 1D-Schrödinger equation to the Bloch sphere representation, leading to a rather clear and intuitive physical picture for the pertinent time dynamics.
Research on key influencing factors and mechanisms of improved nitrogen fixation efficiency in magnetic-driven gliding arc
Authors: Zhang Yingzhe , Liu Baowang , Luo Jingyi , Nie Lanlan , Xian Yubin , Lu Xinpei
Published: December 2023

Gliding arc is considered to be an efficient method for nitrogen fixation. In this study, an improved magnetic-driven rotating gliding arc method was adopted to investigate the effects of gas flow rate, current, magnetic field, nitrogen-to-oxygen ratio in the working gas, and relative humidity on nitrogen fixation efficiency. To further understand the relationship between the discharge mechanism and nitrogen fixation efficiency, the arc length, arc diameter, arc rotation frequency, and reaction pathway were studied to find the relationship between external parameters, discharge characteristics, and nitrogen fixation efficiency. The research results indicate that the discharge current and magnetic field not only change the rotation frequency of the gliding arc, but also affect its length and diameter, and the amount of ionizing gases involved in the working gas, thus affecting nitrogen fixation efficiency. When the nitrogen volume ratio in the feed gas is 60%, the lowest energy cost can be achieved, which is 18.6% lower than that of air. The energy cost of nitrogen fixation is closely related to the humidity of the air. As the humidity increases, the energy cost also increases. At the magnetic field strength of 160 mT, gas flow rate of 10 l min−1, and current of 40 mA, the energy cost of 1.708 MJ mol−1 is realized which is the current lowest for plasma nitrogen fixation in this study.
A football-like acoustic metamaterial with near-zero refractive index and broadband ventilated sound insulation
Authors: Wang Yipu , Chen Wenjiong , Liu Shutian
Published: December 2023

Acoustic metamaterial with negative or near-zero refractive index exhibits extraordinary acoustic transmission characteristics, including acoustic total reflection, acoustic stealth and acoustic tunneling. Based on the coiled-up space structure, a football like near-zero refractive index acoustic metamaterial (FNZIM) was proposed. The result reveals the formation of two transmission peaks at 1270 Hz and 2300 Hz from the equivalent parameters by using the transfer matrix method. The first peak exhibits excellent air impedance matching, while the second peak arising from the metamaterial’s near-zero refractive index. We then constructed an acoustic prism using 15 cells of FNZIM and calculated the dispersion curve, revealing that the near-zero refractive index supernormal transmission of metamaterials is attributable to multimode degeneracy. Furthermore, we find that the positions of the transmission peaks and transmission loss can be adjusted by appropriately altering the structural parameters. Finally, we tested two groups of samples by using impedance tube four-channel to verify the accuracy of the simulation and the validity of insulation performance of FNZIM. The broadband ventilation sound insulation coupled structure is constructed, and the average sound insulation performance of this structure is more than 25 dB in the range of 1140–2210 Hz.
Modeling of a Ti/NiTi spring-blade gear for space micro–vibration isolation
Authors: Zhang Rongru , Yang Yifei , Ma Chao , Ren Rui , Jiang Jun , Liu Xin , Yue Honghao , Lu Yifan
Published: December 2023

Space pointing mechanisms are crucial in space scientific experiments and observations. Since the precision of such mechanisms is highly susceptible to micro–vibrations due to environmental disturbances and inherent defects, isolating micro–vibrations is important. A low rotational stiffness spring-blade gear installed on the output shaft of the stepper motor can isolate micro–vibrations due to the motor’s discontinuous rotation. However, a quantitative performance description is still lacking. In this paper, a rotational stiffness model for the spring-blade gear made of titanium and nickel–titanium-based shape memory alloy is established and experimentally validated. A vibration transmissibility model is developed, revealing the relationships among the layout, material properties, structural parameters, external loads, rotational stiffness, and vibration transmissibility of the spring-blade gear. This paper can be used to design and optimize the spring-blade gear, predicting the isolation and suppression capability against micro–vibrations at different frequency ranges. The optimal gear structure can be obtained according to vibration isolation requirements, load, and installation constraints to achieve the predetermined vibration isolation effect. This study can ensure the space pointing mechanisms operate with high precision and stability by attenuating space micro–vibrations effectively, improving the quality of signal acquisition and observation accuracy.
Variation of effective filament diameter, irreversibility field, anisotropy, and pinning efficiency in Bi-2212 round wires
Authors: Tarantini Chiara , Barua Shaon , Oloye Temidayo Abiola , Kametani Fumitake , Jiang Jianyi , Hellstrom Eric E , Larbalestier David C
Published: December 2023

In recent years Bi2Sr2CaCu2O
x
(Bi-2212) received increasing attention due to its round wire multifilamentary architecture, a unique feature in high-Tc
superconductor. In fact, round wires are preferable for magnet designs, including solenoids for nuclear magnetic resonance (NMR) or research purpose and accelerator magnets. However, due to the narrow over-pressure heat treatment conditions necessary to obtain high Jc
and to the peculiar microstructure of Bi-2212 wires, a full understanding of the correlations between the different properties has not yet been developed. In this paper we investigate the effect of a vital part of Bi-2212 optimization, the maximum heat-treatment temperature T
max in the range of 885 °C–896 °C, on the variations of Jc
, effective filament diameter d
eff, anisotropy γ, INTER- and intra-grain irreversibility fields and pinning energies U
0, all critical parameters in unravelling the complex mix of vortex pinning and connectivity that ultimately determines the critical current density. We found that d
eff of the higher Jc
wires heat-treated at lower temperature is much smaller than for the lower Jc
wires. Moreover, a systematic increase of the irreversibility field and a decrease of the intrinsic Bi-2212 anisotropy underpins the higher Jc
. The analysis of the pinning energies reveals that there is little sample-to-sample variation in the INTER-grain pinning, whereas in all samples the intra-grain pinning has an enhancement below ∼40–45 K becoming more and more evident with increasing Jc
. These results suggest that the overall Jc
performance are not only related to the wire microstructure and connectivity, which obviously affect the INTER-grain properties, but they are also intimately related to the intrinsic and intra-grain properties such as γ and U
0.
Degenerate behaviors and decompositions of the two-soliton solution in the (1+1)-dimensional Ito equation
Authors: Wang Lirong , Wang Chuanjian , Li Changzhao , Wang Yuye
Published: December 2023

In this paper, we investigate the degenerate behaviors and decompositions of two-soliton solution on the non-vanishing constant background for the (1+1)-dimensional Ito equation. By tuning the background constant, interaction phenomena of various types such as the elastic interaction of solitons, fission or fusion phenomena are presented. The degenerate two-soliton solutions which lead to a higher amplitude soliton in collisions of two solitons or describe the decay of a soliton into two new solitons are obtained. To better understand the nature of these interaction phenomena, we explore different decompositions to express the two-soliton solution as a sum of two functions. One of the function exhibits a special soliton excited by the collisions of two solitons, and the other describes the energy exchange of two solitons. Finally, under the module resonance of wave numbers, other types of the degenerate solutions of two solitons are derived and analyzed, such as the breather and rogue wave solutions.
Electronic nonequilibrium effect in ultrafast-laser-irradiated solids
Authors: Medvedev Nikita
Published: December 2023

This paper describes the effects of electronic nonequilibrium in a simulation of ultrafast laser irradiation of materials. The simulation scheme based on tight-binding molecular dynamics, in which the electronic populations are traced with a combined Monte Carlo and Boltzmann equation, enables the modeling of nonequilibrium, nonthermal, and nonadiabatic (electron-phonon coupling) effects simultaneously. The electron-electron thermalization is described within the relaxation-time approximation, which automatically restores various known limits such as instantaneous thermalization (the thermalization time

τ

e
−
e

→
0

) and Born-Oppenheimer (BO) approximation (

τ

e
−
e

→
∞

). The results of the simulation suggest that the non-equilibrium state of the electronic system slows down electron-phonon coupling with respect to the electronic equilibrium case in all studied materials: metals, semiconductors, and insulators. In semiconductors and insulators, it also alters the damage threshold of ultrafast nonthermal phase transitions induced by modification of the interatomic potential due to electronic excitation. It is demonstrated that the models that exclude electron-electron thermalization (using the assumption of

τ

e
−
e

→
∞
,

such as BO or Ehrenfest approximations) may produce qualitatively different results, and a reliable model should include all three effects: electronic nonequilibrium, nonadiabatic electron-ion coupling, and nonthermal evolution of interatomic potential.
Effects of connected automated vehicle on stability and energy consumption of heterogeneous traffic flow system
Authors: Shen 申 Jin 瑾 , Zhao 赵 Jian-Dong 建东 , Liu 刘 Hua-Qing 华清 , Jiang 姜 Rui 锐 , Yu 余 Zhi-Xin 智鑫
Published: December 2023

With the development of intelligent and interconnected traffic system, a convergence of traffic stream is anticipated in the foreseeable future, where both connected automated vehicle (CAV) and human driven vehicle (HDV) will coexist. In order to examine the effect of CAV on the overall stability and energy consumption of such a heterogeneous traffic system, we first take into account the interrelated perception of distance and speed by CAV to establish a macroscopic dynamic model through utilizing the full velocity difference (FVD) model. Subsequently, adopting the linear stability theory, we propose the linear stability condition for the model through using the small perturbation method, and the validity of the heterogeneous model is verified by comparing with the FVD model. Through nonlinear theoretical analysis, we further derive the KdV-Burgers equation, which captures the propagation characteristics of traffic density waves. Finally, by numerical simulation experiments through utilizing a macroscopic model of heterogeneous traffic flow, the effect of CAV permeability on the stability of density wave in heterogeneous traffic flow and the energy consumption of the traffic system is investigated. Subsequent analysis reveals emergent traffic phenomena. The experimental findings demonstrate that as CAV permeability increases, the ability to dampen the propagation of fluctuations in heterogeneous traffic flow gradually intensifies when giving system perturbation, leading to enhanced stability of the traffic system. Furthermore, higher initial traffic density renders the traffic system more susceptible to congestion, resulting in local clustering effect and stop-and-go traffic phenomenon. Remarkably, the total energy consumption of the heterogeneous traffic system exhibits a gradual decline with CAV permeability increasing. Further evidence has demonstrated the positive influence of CAV on heterogeneous traffic flow. This research contributes to providing theoretical guidance for future CAV applications, aiming to enhance urban road traffic efficiency and alleviate congestion.
Thermodynamic and dynamic contributions to the abrupt increased winter Arctic sea ice growth since 2008
Authors: Yi Daling Li , Fan Ke , He Shengping
Published: December 2023

The area of Arctic winter sea ice growth (WSIG) has expanded dramatically since winter 2008. Yet the thermodynamic and dynamic contributions to the abrupt increase in WSIG remain unclear. Here using an ice concentration budget, we characterized quantitatively the increasing WSIG and revealed the relative contributions of dynamics during 1985–2021. Ice dynamics related to ice convergence/divergence are compared in two representative regions. The northern Laptev Sea is a freezing-dominated ice growth region and is competitively driven by the ice convergence. While in northwest Beaufort Gyre (BG), the combined effects of freezing and ice divergence have both enhanced since 2008, and the dynamics contribute 84% to the significant WSIG intensification since 2008. Comparison of thermodynamic and dynamic contributions emphasized that the winter sea-ice expansion is influenced not only by winter freeze, but also by convergence/divergence relative to newly formed thinner and mobile ice. Furthermore, the amplified summer Beaufort High in the mid-2000s and its long-lasting memory of the wind-driven strengthened BG are partially attributed to the abrupt increased WSIG since 2008.
Overview of Axial Flux Permanent Magnet Generator for Small-Scale Industry
Authors: Mostaman Nur Afiqah , Sulaiman Erwan , Jenal Mahyuzie
Published: December 2023

A magnetic generator is not like a conventional generator that is produced by the coil. Consequently, this generator used the permanent magnetic field to produce magnetic flux energy. Although, most of the permanent magnet designs produce less aggressive copper winding. This paper provides an overview of axial flux permanent magnet generators for small-scale industries. First of all, the classification and a detailed overview of permanent magnet generators are presented first. The main characteristics of the generators together with their benefits and drawbacks are highlighted. Additionally, an overview of the most recent machine developments is also presented. The design of convenient permanent magnet generators that have been used to create small-scale generator varieties is then reviewed to conclude the most suitable design among axial flux which is the sandwiched construction.
Design Data Logger for PV Analyzer Based on Arduino
Authors: Effendi Asnal , Dewi Arfita Yuana , Antonov
Published: December 2023

Designing a data logger for an Arduino-based PV analyzer. The goal is to analyze the energy yield of PV. The sensors used are current and voltage sensors integrated into the data logger board to measure parameters that affect the efficiency value of the PV array. Analyzers help measure and record output parameters of PV systems such as current, voltage, and power. The device also can store parameter data such as Temperature affecting PV performance. The advantage of using data loggers is that data can be collected automatically over some time. Additionally, the data can be displayed in the form of V-I and P-V diagrams for analytical purposes. This sequential design can be used for PV systems that provide many components with a specific power. Test-bench results were recorded at a maximum output of 20,016W. This type of data logger can be used as a portable recorder for measuring PV performance in different areas.
The Influence of Nanofluid Characteristics on the Thermal Performance of Photovoltaic Thermal System
Authors: Umam Mukhamad Faeshol , Hasanuzzaman Md , Rahim Nasrudin Abd
Published: December 2023

Optimal solar energy utilization can be achieved with a Photovoltaic Thermal (PVT) system, which simultaneously produces electricity and heat. PVT generally uses water as heat transfer fluid to cool the PV cells while transporting heat for other purposes. However, water has low thermal conductivity and capacity as a heat transfer fluid. Nanofluid, which is popular in heat exchanger applications, has also been researched and tested for use in improving the performance of PVT systems. The superior thermal conductivity of nanofluid could produce a PVT system efficiency of up to 89.75%. However, nanofluid applications in the PVT system still face challenges, especially in their preparation and properties. This study determines the properties of nanofluids that could improve the electrical and thermal performance of PVT systems. The authors found that preparation procedures for manufacturing nanofluids were essential for researchers to consider before applying nanofluids. Also, some disadvantages of nanofluids are still an obstacle in their application, especially economic issues and adverse environmental effects.