bluuebunny/crossref_metadata_2025 huggingface dataset:
Transport enhancement in the laminar rotating disk boundary layer
Authors: Mehmood Ahmer , Weigand Bernhard , Usman Muhammad
Published: August 2024

Enhanced momentum and heat transport in a three-dimensional rotating disk boundary layer due to the consideration of a wavy disk surface is an already known fact in the literature. Such a transport enhancement is primarily associated with two fundamental attributes of the wavy disk: the increased surface area and the enhanced convection due to the surface undulations. However, there exists no further information about their individual role, mutual interaction, and individual share in enhancing the convective transport in the rotating disk boundary layer. This study aims to investigate these facts in detail by considering radially heterogeneous different wavy configurations on the disk surface. It is revealed that the said attributes contribute non-trivially to enhance the transport phenomena. Their impactful role is identified due to the strengths of circumferential and crossflow velocity components, the magnitude of flow swirl angle, and hence due to the coefficients of skin friction and their inter relationship. In this regard, a fundamental benchmark regarding the relative strength of the two coefficients of skin friction is identified from the flat disk case. Decisive observations regarding the impact of surface undulations and the increased surface area of the wavy disk on the enhanced convective transport are made with the aid of this benchmark. It is observed that the enhanced transport phenomena, especially the heat transfer, mainly depend upon the further dominance of the circumferential velocity component. In the situations of increased dominance of rotational flow Kw>Kf, the increased convection and surface area collectively contribute to enhance the thermal transport while in a reverse situation Kw<Kf the convection contributes adversely by even reducing the impact of the increased surface area. In the neutral situation where the dominance of rotational velocity is neither increased nor decreased (i.e., Kw≈Kf), any increase in the transport phenomena is wholly due to the increased surface area. Therefore, the presence of surface undulations or increase in surface area is not the only criterion for an optimum rise in the transport phenomena, rather the impact of surface undulations on the velocity profiles is important which is manipulated due to their positioning on the disk surface. It is observed that the presence of surface undulations in the central and intermediate regions on the disk surface causes to increase the gradients of the crossflow velocity while their presence in the near rim location causes to enhance the gradients of the circumferential velocity. Thus, the configurations that have higher undulations in the near rim region outperform the other configurations.
Bayesian reverse design of high-efficiency perovskite solar cells based on experimental knowledge constraints
Authors: Liu Hongyu , Chen Zhengxin , Zhang Yaping , Wu Jiang , Peng Lin , Wang Yanan , Liu Xiaolin , Chen Xianfeng , Lin Jia
Published: August 2024

To alleviate high costs and lengthy trial-and-error periods associated with traditional optimization methods for perovskite solar cells (PSCs), we developed a data-driven reverse design framework for high-efficiency PSCs. This framework integrates machine learning and Bayesian optimization (BO) to accelerate the optimization process of PSCs by intelligently recommending the most promising parameter configurations for PSCs, such as device structure and fabrication processes. To improve the robustness of the framework, we first designed a two-stage sampling strategy to alleviate the issue of imbalanced dataset classes. Subsequently, by integrating “experimental knowledge constraints” into the BO process, we achieved precise parameter configurations, thus avoiding discrepancies between predicted and actual results due to parameter mismatches. Finally, using SHapley Additive exPlanations, we unveiled key factors influencing the power conversion efficiency (PCE), such as the composition of perovskite solvents. Our framework not only precisely predicted the PCE of PSCs with an area under the curve of 0.861 but also identified the optimal parameter configurations, achieving a high probability of 0.981. This framework offers substantial support for minimizing redundant experiments and characterizations, effectively accelerating the optimization process of PSCs.
Stabilization of interconnected models with Nitsche's interface conditions using the two-grid approach: A finite element study
Authors: Hussain Shahid , Mahbub Md. Abdullah Al , Feng Xinlong , Rana Fateh Ali , Haq Fazal , Hussain Arshad
Published: August 2024

In this paper, a stabilized Stokes–Stokes system with Nitsche's type interface conditions is presented. These conditions are commonly employed in many multi-physical fields, including fluid–fluid interaction, fluid–structure interaction, oceanographic modeling, and atmospheric forecasting. For multi-physical domain modeling purposes, Nitsche's interface conditions provide useful benefits over classical conditions via addressing the complicated nature of fluid phase interface mathematical modeling, phase boundary tracking, interface interactions, and mass and energy transportation. It is not easy to find analytical and numerical solutions for models with these characteristics. We use more accurate interface conditions to solve the fluid–fluid interaction model to accomplish this numerically. This is achieved by including new terms at the interface and decoupling the domain through the two-grid technique, which ultimately reduces the main issue into several smaller problems. Comparing this method to existing models, we find that it is computationally feasible because it uses less memory and operates with a coarse grid instead of a fine grid and thus improves convergence rates for complex and nonlinear problems. Furthermore, it shows mesh independence, supports potential parallelization, and is crucial for advanced multigrid techniques. The optimality of the error is confirmed both theoretically and numerically. The numerical experimental section validates the model through three types of numerical experiments.
Designing an imaging spectrometer with high resolution using manufacturable gradient-index (MGRIN) lenses with a linear distribution of refractive index
Authors: Rezaei-latifi Ali
Published: August 2024

In this work, an imaging spectrometer with a diffraction-limited resolution of 0.043 nm is designed by using two manufacturable gradient-index (MGRIN) lenses with a linear refractive index distribution to suppress the aberrations. The MGRIN lenses are made from a combination of two separate base materials that their refractive indices are determined by the fractional composition of each base material at any point. The volume fraction of each base material in both lenses changes linearly from the front edge to the rear vertex of the lens. The input light to the spectrometer originates from a single-mode fiber with a core diameter of 9 μm and a numerical aperture of 0.1. The parallel rays after passing through the collimator are diffracted by a diffraction grating with a number of grooves of 1200 g/mm. The criteria determining the quality of the image show that the aberrations of the image have been optimally controlled. Comparing the results of this design with some similar studies done by other researchers shows that the root-mean-square radius of the spot diagram and Airy disk radius are significantly smaller than those designs. In addition, the modulation transfer function diagram has a better fit with the diffraction limit curve. These results make our proposed spectrometer have a stronger resolution than those in previous studies.
Unconditionally optimal high-order weighted compact nonlinear schemes with sharing function for Euler equations
Authors: Zhi Yan , Chen Yaming , Zhang Zixuan , Zhao Haiyang , Deng Xiaogang
Published: August 2024

Weighted compact nonlinear schemes (WCNS) are a type of high-order shock-capturing finite difference schemes commonly used in various applications. Their spatial discretizations involve a nonlinear interpolation step and a linear difference step. However, the nonlinear interpolation step requires significantly more computational resources compared to the linear difference step. Therefore, simplifying the interpolation step is an effective way to improve the efficiency of these schemes. In this paper, we propose a new approach to construct WCNS schemes based on the sharing function for Euler equations. This approach uses a set of common nonlinear interpolation weights for different components, resulting in a significant improvement in efficiency compared to the original WCNS schemes that use different sets of weights for each component. To ensure accuracy at critical points of any orders, we employ nonlinear weights that guarantee unconditionally optimal high order. Additionally, this new approach may reduce oscillations caused by non-characteristic interpolation. Furthermore, we also develop a new shock detector using the sharing function, enabling us to employ characteristic interpolation for nonsmooth regions and linear component-wise interpolation for the rest. We validate the proposed schemes based on the sharing function through numerical examples of one- and two-dimensional Euler equations, demonstrating their effectiveness in terms of shock-capturing capability and efficiency.
Development of the prototype for the SPARC hard X-ray monitor
Authors: Panontin E. , Tinguely R. A. , Hartwig Z. S. , Saltos A. A. , Vezinet D. , Rice J.
Published: August 2024

The SPARC tokamak will be equipped with a hard X-ray (HXR) monitor system capable of measuring the bremsstrahlung emission from runaway electrons with photon energies in excess of about 100 keV. This diagnostic will detect the formation of runaway electron beams during plasma start-up and inform the plasma control system to terminate the discharge early to protect the machine. In this work, we present a 0D estimate of the HXR emission in SPARC during plasma start-up. Then we discuss the characterization of a prototype of the HXR monitor. The detector mounts a 1 × 1-in.2 LaBr3 inorganic scintillator coupled with a photomultiplier tube and has been tested with γ-ray sources to find its dynamic range. Finally, two possible modes of operation for spectroscopic and current mode measurements on SPARC are proposed.
Strengthening mechanism of large-diameter magnetic particles on ferrofluid nanoparticle chaining
Authors: Jiang Yangyang , Chen Yibiao , Lv Lixiang , Lu Jiacheng , Li Decai , Zhou Hongming
Published: August 2024

The magnetization of nano ferrofluid is lower than that of micrometer magnetorheological fluid, which limits its application in seals, dampers, and various other fields. To enhance the ferrofluid performance, this paper incorporates large-diameter magnetic particles into the ferrofluid to strengthen chaining among nanoparticles. A matrix discrete element method model is constructed to investigate the strengthening mechanism of large-diameter magnetic particles on ferrofluid nanoparticle chaining. Additionally, the chain formation process involving both large and small particles and the influence of large particle volume fractions on chain length, particle number, and yield strength are studied based on the simulation. The results show that small particles and large particles together constitute different complex structures, such as the columnar structure and column-net structure under the strong magnetic dipole force of the large particles, leading to the high chain structure strength. In addition, the chain formation speed, average chain length, average particle number, yield strength, and additional viscosity are influenced by the volume fractions and particle sizes of large particles. The method will enhance the ferrofluid sealing performance and expand the ferrofluid application areas.
Experimental study on the evolution of shock waves in the near field of cylindrical charge explosion
Authors: Ren Meng , Yue Zhongwen , Wang Peng , Xue Kejun , Zhou Xingyuan , Jiang Haoyang
Published: August 2024

Cylindrical charges are frequently used in blasting engineering and military operations, often detonated very close to target structures. Obtaining the characteristics of the flow field distribution in the near field of explosions through experimentation consistently poses challenges. These challenges constrain efforts to elucidate the evolutionary processes of explosive shock waves. Employing the explosive schlieren experimental system yields a clearer depiction of the near field flow than previous studies, thereby facilitating a more comprehensive understanding of the characteristics of cylindrical charge explosions. The overall flow field adopts a droplet shape, with the interface of the detonation products and the shock wave front forming continuous concave shapes. The detonation process in cylindrical charges can be conceptualized as the detonation wave propelling the detonation products at supersonic speeds. The formation of explosive shock waves can be elucidated through the dynamics of oblique shock waves generated by two-dimensional curved surfaces. This mechanism influences the relationship between the deflection angles of detonation products and the shock wave angles resulting from different detonation velocities. Theoretical calculations of shock wave positions align with experimental images. Significant variations in shock wave velocities at different positions within cylindrical charges are observed, identifying patterns of these variations. The research findings clarify the formation mechanisms of explosive shock waves in cylindrical charges and deepen the understanding of shock wave evolution in the near field.
Hydrodynamic interactions between two microswimmers in viscoelastic fluids
Authors: Lin Zhaowu , Zhang Minkang , Chen Xingfan , Cheng Xiaoliang , Yu Zhaosheng
Published: August 2024

We numerically investigate the hydrodynamic interactions between two microswimmers in viscoelastic fluids at low Reynolds number regimes using the fictitious domain method. In the Newtonian fluid, after contact, pushers rotate toward each other and remain in a “trapped” state for a long time, induced by a counterclockwise viscous torque. We believe it is related to the asymmetrical surrounding vortexes. As the pushers approach, two positive vortexes merge into one, disrupting the vortex balance and inducing a net counterclockwise torque on the swimmers. But in the Giesekus viscoelastic fluids, an clockwise elastic torque modifies the pushers' rotations during early contact. Subsequently, two negative vortexes around the pushers merge, generating a clockwise torque that causes the swimmers to separate. Additionally, a huge elastic stretching effect is observed at the rear of the pullers, which restricts their swimming behavior through elastic force. Post-collision, the pullers rapidly separate with a large scattering angle in both Newtonian and viscoelastic fluids. However, neutral swimmers separate with unchanged orientations, and their trajectories remain consistently aligned across various Weissenberg numbers. Furthermore, the elastic force impedes the relative motions of the swimmers and alters the pressure and viscosity force.
Mechanical–thermal coupling in micro-nanocavity graphene/paraffin phase change energy storage materials for heat management
Authors: Wang Yuhao , Yu Junhong , Huang Wentian , Di Jun , Cai Jinming , Hu Jianbo
Published: August 2024

Combining the superior thermal conductivity of graphene and the outstanding heat storage of paraffin, micro-nanocavity graphene/paraffin nanocomposites (MNGPNs) have recently served as promising thermal management materials in high-power microelectronic devices. However, current evaluations of the thermal management performances of MNGPNs are restricted in the lab condition, deviating from the complex mechanical–thermal coupling environment in practical scenarios. Here, we have investigated the structural and thermal management properties of MNGPNs with varying mechanical loads by in situ electron microscopy and in situ thermal characterizations. Our results reveal distinct mechanical–thermal coupling effects along in-plane and out-of-plane directions of MNGPNs. Specifically, mechanical loading reduces the porosity and enhances the heat transfer capacity of MNGPNs in the out-of-plane direction, while mechanical loading along the in-plane direction causes local damage to the graphene structure and weakens the heat transfer capacity of MNGPNs. Since the heat management performance of MNGPNs is dominated by the in-plane thermal transport, MNGPNs with mechanical loading show a delayed phase transition response time and unchanged phase transition enthalpy. This work provides in situ mechanical guidance for the practical application of MNGPNs for heat management.
Different kinds of accelerated propagation of relativistic electromagnetic plasma wavepackets
Authors: Asenjo Felipe A.
Published: August 2024

Relativistic electromagnetic plasma waves are described by a dynamical equation that can be solved not only in terms of plane waves, but also for several different accelerating wavepacket solutions. Depending on the spatial and temporal dependence of the plasma frequency, different kinds of accelerating solutions can be obtained, for example, in terms of Airy or Weber functions. Also, we show that an arbitrary accelerated wavepacket solution is possible, for example, for a system with a luminal plasma slab.
Comment on “ENN's roadmap for proton-boron fusion based on spherical torus” [Phys. Plasmas 31, 062507 (2024)]
Authors: Li Zhi
Published: August 2024

This comment discusses the feasibility of hot ion mode Ti/Te=4 for proton–boron fusion, which is critical for the roadmap proposed in Liu et al. [Phys. Plasmas 31, 062507 (2024)]. The hot ion mode Ti/Te=4 has been calculated to be far from accessible (Ti/Te<1.5 for Ti=150 keV) under the most optimal conditions if fusion provides the heating [Xie, Introduction to Fusion Ignition Principles: Zeroth Order Factors of Fusion Energy Research (USTC Press, Hefei, 2023)], i.e., that all fusion power serves to heat the ions and that electrons acquire energy only through interactions with ions. We also discuss if hot ion mode of Ti/Te=4 could be achieved by an ideal heating method, which is much more efficient than fusion itself (near 20 times fusion power for Ti=150 keV) and only heats the ions, whether it makes sense economically.
Symmetric irrotational deep-water waves are traveling waves
Authors: Li Jian , Yang Shaojie
Published: August 2024

In this paper, we show that a periodic solution to the irrotational two-dimensional deep-water wave problem with the horizontal velocity components at the surface, and wave profiles are symmetric, and periodic in the x-variable, necessarily defines a traveling wave. The proof relies on employing the Maximum principle for harmonic functions in unbounded domains and structural properties of the governing equations for nonlinear deep-water waves.
Understanding the relationship between intergenerational mobility and community violence
Authors: Mann Olivia , Edin Kathryn J. , Shaefer H. Luke
Published: August 2024

Violence is a key mechanism in the reproduction of community disadvantage. The existing evidence indicates that violence in a community impacts the intergenerational mobility of its residents. The current study explores the possibility of a reverse relationship. This study provisionally tests the hypothesis that depressed intergenerational mobility in a community may also spark subsequent community violence. We deploy a county measure of intergenerational mobility captured during early adulthood for a cohort of youth born between 1980 and 1986 and raised in low-income families [R. Chetty, N. Hendren,Quart. J. Econom.133, 1163–1228 (2018)]. We model the relationship between county mobility scores and two county-level outcomes: violent crime and homicide. We find that a county’s level of intergenerational mobility as measured by the Chetty–Hendren data is a major predictor of its rate of violent crime and homicide in 2008, when the youth in Chetty’s mobility cohort were young adults (the same age the mobility measure was captured). In fact, mobility is a significantly stronger and more consistent predictor of community violent crime and homicide rates than more commonly used factors like poverty, inequality, unemployment, and law enforcement presence.
Historical Southern Hemisphere biomass burning variability inferred from ice core carbon monoxide records
Authors: Strawson Ivo , Faïn Xavier , Bauska Thomas K. , Muschitiello Francesco , Vladimirova Diana O. , Tetzner Dieter R. , Humby Jack , Thomas Elizabeth R. , Liu Pengfei , Zhang Bingqing , Grilli Roberto , Rhodes Rachael H.
Published: August 2024

Biomass burning plays an important role in climate-forcing and atmospheric chemistry. The drivers of fire activity over the past two centuries, however, are hotly debated and fueled by poor constraints on the magnitude and trends of preindustrial fire regimes. As a powerful tracer of biomass burning, reconstructions of paleoatmospheric carbon monoxide (CO) can provide valuable information on the evolution of fire activity across the preindustrial to industrial transition. Here too, however, significant disagreements between existing CO records currently allow for opposing fire histories. In this study, we reconstruct a continuous record of Antarctic ice core CO between 1821 and 1995 CE to overlap with direct atmospheric observations. Our record indicates that the Southern Hemisphere CO burden ([CO]) increased by 50% from a preindustrial mixing ratio of ca. 35 ppb to ca. 53 ppb by 1995 CE with more variability than allowed for by state-of-the-art chemistry-climate models, suggesting that historic CO dynamics have been not fully accounted for. Using a 6-troposphere box model, a 40 to 50% decrease in Southern Hemisphere biomass-burning emissions, coincident with unprecedented rates of early 20th century anthropogenic land-use change, is identified as a strong candidate for this mismatch.
Disappearing iconicity in the evolution of Polish Sign Language
Authors: Eźlakowski Wiktor
Published: August 2024

In this article, I look at the evolution of Polish Sign Language by closely analyzing the sign słodki
‘sweet’ at all of the stages of its development known to us. By closing in on just one sign we can see that the evolution of a
sign is a very complex process. The sign słodki ‘sweet’ has gradually lost its iconic character over time. This is
primarily due to linguistic factors, while societal factors have also impacted the sign’s transparency. Although at its inception
słodki ‘sweet’ might have been considered iconic and its meaning transparent, today the sign’s motivation would be
unclear to people seeing it for the first time, including to native Polish Sign Language users. The sign has undergone many
different processes, such as assimilation, channel clearing, reduction and analogy. These processes are discussed in the article
in depth; along with a change in society, they have resulted in the etymology of the sign being unknown to users of Polish Sign
Language.
Evaluating written versus audio feedback in formative assessment of consecutive interpreting
Authors: Han Chao , Chen Shirong
Published: August 2024

In formative assessment, teacher feedback can enhance student learning. To reap such benefits, educators need to
deliver feedback in such a way that arouses students’ learning interest, invites their active engagement, and inspires follow-up
action. We report on an exploratory qualitative study that compares two modalities of teacher feedback, namely, written versus
audio feedback, provided to a group of 41 students in a consecutive interpreting course. Our qualitative content analysis of the
students’ responses to the questionnaire reveals 25 lower-order themes, categorized into seven higher-order themes concerning
inherent properties (informational, structural, and prosodic) and consequential aspects (communicative, functional, affective, and
metacognitive) of written/audio feedback. Overall, the results seem to show the students’ preference for the audio feedback,
because of its informativeness, specificity, interactivity, and affective/cognitive benefits. We discuss these results in terms of
students’ learning gains, learning style, task-feedback alignment, and relationship between feedback specificity and modality for
interpreter training.
Warm inflation with bulk viscous pressure for different solutions of an anisotropic universe
Authors: Shokri Mehdi , Sadeghi Jafar , Herrera Ramón , Noori Gashti Saeed
Published: August 2024

We study a warm inflationary model for different expansions assuming an anisotropic universe described by Bianchi I metric. The universe is filled with a scalar field or inflaton, radiation, and bulk viscous pressure. We carry out the inflationary analysis for different solutions of such universe in two different cases of the coefficient of dissipation Γ and the coefficient of bulk viscosity ξ as constant and variable parameters, respectively. We compare the obtained results with the recent observations, in order to find the observational constraints on the parameter space of the models. Moreover, we attempt to present a better judgment among the considered models by calculation of the non-linear parameter f
NL describing the non-Gaussianity property of the models.
Spacing mode multi-wavelength erbium doped fiber laser based on a symmetrical long-period fiber grating
Authors: Contreras-Teran M A , Gallegos-Arellano E , Jauregui-Vazquez D , Martinez-Rios A , Hernandez-Garcia J C , Reyes-Ayona J R , Sierra-Hernandez J M
Published: August 2024

We present a multiwavelength erbium-doped fiber laser based on a symmetrical long-period fiber grating (LPFG) with tunable spacing mode between single lasing mode and multiwavelength spectra. The LPFG was manufactured using a thermal expansion technique using an LZM-100 glass processing system equipped with a CO2 laser, and it was used as a wavelength-selective filter (WSF) in the laser ring cavity. The laser can emit single, double, triple, quadruple, quintuple, or sextuple lines in the range from 1546 to 1563 nm, which can be tunable by controlling the radius of curvature of the LPFG in the range 0–0.2662 m −1. A minimal spacing mode of 1.92 nm was observed in the multiwavelength region; meanwhile, the fiber laser offers an average spacing mode of 6.945 nm between the multiwavelength region and the single emission. This laser has a 3 dB linewidth of 0.11 nm and a side mode suppression ratio (SMSR) of 55.56 dB. Finally, according to experimental results, the laser has high wavelength stability at room temperature for 88 min.
Controlling the polarization through opposite orthogonal transformation with coupling-optimized composite metasurface
Authors: Yao Weiyu , Qiu Zhenqi , Wen Haozhe , Gu Wei , Shao Yan , Yang Yang , Tang Hongying , Luo Yang
Published: August 2024

The flexible manipulation of incident polarized waves enhances design freedom for integrated and miniaturized THz devices. This work proposes a method of orthogonal decomposition and transformation to manipulate the polarization of incident fields. It enables symmetric mapping with respect to the S2 axis (x = y) on the Poincaré sphere for any polarized waves. Consequently, arbitrary deflection can be achieved by adjusting the angle between the incident wave and the device. Additionally, the spin will be reversed for circularly and elliptically polarized waves. A specific metasurface is designed to implement this proposal, incorporating a precisely tailored coupling structure to optimize the interaction between cells, which is crucial for maintaining transmittance and bandwidth. All designs are thoroughly validated through numerical simulations. This adaptability and flexibility make it suitable for various applications, including waveplates, polarization convertors and detectors, antennas and radars, etc.
Effects of gravitational particle production on Higgs portal dark matter
Authors: Izumine Soichiro , Nakayama Kazunori
Published: August 2024

The gravitational interaction is ubiquitous and the effect of gravitational particle production necessarily contributes to the dark matter abundance. A simple candidate of dark matter is a scalar particle, whose only renormalizable interaction is the Higgs portal coupling. We show that the abundance of Higgs portal dark matter is significantly affected by the gravitational production effect. In particular, the gravitational production from the coherently oscillating inflaton field during the reheating often gives dominant contribution.
Exocomet Models in Transit: Light Curve Morphology in the Optical—Near Infrared Wavelength Range
Authors: Kálmán Szilárd , Szabó Gyula M. , Kiss Csaba
Published: August 2024

Following the widespread practice of exoplanetary transit simulations, various presumed components of an extrasolar system can be examined in numerically simulated transits, including exomoons, rings around planets, and the deformation of exoplanets. Template signals can then be used to efficiently search for light curve features that mark specific phenomena in the data, and they also provide a basis for feasibility studies of instruments and search programs. In this paper, we present a method for exocomet transit light curve calculations using arbitrary dust distributions in transit. The calculations, spanning four distinct materials (carbon, graphite, pyroxene, and olivine), and multiple dust grain sizes (100–300 nm, 300–1000 nm, and 1000–3000 nm) encompass light curves in VRJHKL bands. We also investigated the behavior of scattering colors. We show that multicolor photometric observations are highly effective tools in the detection and characterization of exocomet transits. They provide information on the dust distribution of the comet (encoded in the light curve shape), while the color information itself can reveal the particle size change and material composition of the transiting material, in relation to the surrounding environment. We also show that the typical cometary tail can result in the wavelength dependence of the transit timing. We demonstrate that multi-wavelength observations can yield compelling evidence for the presence of exocomets in real observations.
Particle transport in reduced turbulence neutral beam heated discharges at Wendelstein 7-X
Authors: Bannmann S. , Ford O. , Poloskei P.Zs. , Svensson J. , Pavone A. , Kwak S. , Hoefel U. , Pasch E. , Fuchert G. , Smith H.M. , Lazerson S. , McNeely P. , Rust N. , Hartmann D. , Wolf R.C. ,   the W7-X Team
Published: August 2024

A spontaneous reduction in anomalous particle transport in the plasma core is seen experimentally in reproducible, purely neutral beam heated plasma phases at Wendelstein 7-X (W7-X). Heating and fueling the plasma exclusively with the neutral beam injection system for several seconds leads to continuously peaking plasma density profiles with strong gradients inside mid minor radius. A significant acceleration of the density peaking occurs after a certain onset time and is examined with a detailed particle transport analysis in several discharges. By invoking the particle continuity equation, the total experimental radial electron flux is deduced from the time evolution of the electron density profile and the radially resolved particle sources. Subtracting the modeled neoclassical particle flux contribution gives the anomalous particle flux. Exploiting the evolving plasma conditions, anomalous diffusion and convection coefficients are computed from the flux variation with density and density gradients. In several discharges a significant and consistent change of the anomalous transport coefficients is seen when crossing a specific normalized density gradient length.
3D skeletal muscle tissue culture in vitro by using hydrogel interpenetrating network
Authors: Wu Pengwen
Published: August 2024

Muscle cells can not only be used for pathological research and drug detection, but also can be combined with soft robots to form biological hybrid robots. Mature muscle tissue had advantages such as good elasticity, self-repair, and multi-signal perception. Although there are many methods for 3D muscle tissue culture, muscle tissue is difficult to be used due to the insufficient material properties and long culture period. In this study, we exploited the excellent physicochemical properties of hydrogel materials to develop a new novel interpenetrating hydrogel network structure as a culture framework, and 3D cell culture and tissue induction culture were combined to culture 3D muscle tissue in hydrogel environment and induce differentiation into muscle tissue. The results successfully induce cell proliferation, differentiation and myotube formation in vitro, provide a new idea for the rapid cultivation of muscle tissue in vitro and provide a basis for the assembly of soft robots in the future.
Research on hydrological survey and forecasting model based on rolling sampling Markov chain
Authors: Yi Wei , Qian Peiqing
Published: August 2024

Hydrological survey is of great significance in flood disaster warning, hydropower engineering construction, and efficient utilization of watershed resources. Due to the seasonal and random fluctuations of hydraulic resources, it is difficult to accurately predict waterway runoff. Based on this, this article proposes a hydrological survey and prediction method based on rolling sampling Markov chain. Firstly, based on historical hydrological and meteorological data, establish a watershed runoff model and summarize and analyze the characteristics of the patterns; Then, based on the first-order Markov chain model, the relationship between adjacent days is considered. According to seasonal and meteorological factors, the historical data is rolling sampled in a 10 day sampling interval, and a multi state transition probability matrix is established to construct a year-round time-series runoff forecasting model; Finally, taking the Jinsha River Basin as an example, the annual runoff situation of the waterway was simulated. The calculation results have verified the effectiveness of the proposed method, indicating that it can simulate runoff well and provide certain guidance for watershed management and construction.
Practical application mode and future development of multi-energy coupling system
Authors: Li Yangrunze
Published: August 2024

Compared with the single energy structure in the past, the energy coupling system can realize the coordinated planning and mutual economic regulation among various energy systems, which plays an important role in improving the efficiency of energy utilization. At present there are many related studies but there is a lack of systematic summary. Combining the domestic actual situation, the article mainly lists several multi-energy coupling systems including EWN, IES, BPG, etc., to analyze the energy sources, structural composition and how these systems play a good role in improving energy efficiency, it also summarizes the present situation of comprehensive energy coupling system development research and the shortcomings of current research and prospects for future development are put forward.
A full-scale complementary dynamic comparator
Authors: Xi Yinzheng , Li Nan , Diao Jietao , Hong Junqi
Published: August 2024

This paper presents a dynamic comparator that achieves precise comparison across the entire full-scale range. The comparator, an essential component module in analog-to-digital converters (ADCs), is influenced by its input signal range, speed, and offset voltage, all of which impact the ADC’s performance. In the proposed comparator, a pre-amplification stage using PMOS as the input is incorporated alongside the comparator utilizing NMOS as the input, creating a complementary structure. This design ensures that at least one pre-amplification stage operates effectively, thereby maintaining the accuracy of the comparator as the input signal varies across the entire full-scale voltage range (0 to VDD). Through sound circuit design, the proposed comparator effectively avoids introducing additional distortion and noise. The performance of the comparator is verified under the 180 nm process. The comparator achieves accurate comparison across the entire full-scale range, with a standard deviation σ of the input offset voltage of 6 mV, noise of 450 uV, and a layout area of 467.36 um2. Simulation results demonstrate that the comparator exhibits excellent performance, providing stability assurance for the ADC and extending the ADC’s input signal range.
An FPGA-Based signal acquisition system for 3D holographic azimuthal electromagnetic resistivity logging instruments
Authors: Sun Baojiang , Xu Kai , Zhang Fangfang , Xiao Jiaqi , Liu Xiao
Published: August 2024

A signal acquisition system of a 3D holographic azimuthal electromagnetic resistivity logging instrument while drilling is designed based on the Field Programmable Gate Array (FPGA). The azimuth electromagnetic wave resistivity logging instrument is mainly composed of transmitting coils, receiving coils, and control circuits. The signal acquisition system mainly includes the receiving coil and corresponding signal acquisition and processing circuit. First of all, the whole structure of the electromagnetic wave resistivity instrument system while drilling is briefly introduced, and then each function module of the acquisition board is elaborated in detail, and the hardware realization of the signal acquisition module and the corresponding FPGA program design flow chart are given. The acquisition system makes full use of the structured design of the module and First input First output (FIFO) cache technology and can complete the functions of signal acquisition, data transmission, and control on the acquisition board in real-time by using Serial Communication Interface (SCI) information transmission interface. The simulation results show that the system can realize the function of data acquisition and processing well.
Planar array sparse distribution based on T-2GWO algorithm
Authors: Wang Xiao , Zhang Liang , Meng Xiangdong
Published: August 2024

This paper introduces an approach termed T-2GWO (Tent chaos-dual channel Grey Wolf Optimization) algorithm designed for achieving sparse distribution within constrained position ranges for planar arrays. The initial population is generated by using the Tent Chaos algorithm, modeling individual coordinate positions within the population as a two-channel matrix. Subsequently, the Grey Wolf Algorithm is employed for optimization purposes. The algorithm has verified its effectiveness under the assumption of uniform excitation and can obtain the minimum peak side lobe level, reaching peak side lobe levels of -25.78 dB and - 26.15 dB in the azimuth and pitch directions. Compared with the genetic algorithm, the reduction is 3.53 dB and 10.32 dB respectively. At the same time, better main beam radiation can be obtained.
Design of three-dimensional integrated microsystems for intelligent space storage
Authors: Ren Xiangyu , Zhang Qingxue , Zhang Zhixiang , Li Kui , Yang Yujun
Published: August 2024

To meet the domestic intelligent storage demands for space exploration and satellite missions, this paper explores the indigenous development of intelligent storage through research on process technology, thermal simulation technology, and testing techniques for three-dimensional integrated microsystems for space intelligence storage. The study achieves high-density functional integration of domestically produced space intelligent storage three-dimensional integrated microsystems. The intelligent storage module, with microsystem technology at its core, provides a more efficient application space for miniaturization, lightweight design, high-density integration, and high reliability.
Simulation study of the effect of electrode polarity on microscale corona discharge characteristics
Authors: Xiang Jianhui
Published: August 2024

The occurrence and application scenarios of micro-scale corona discharge are diverse, and the effect of micro-scale corona discharge mechanism and needle electrode polarity on corona discharge characteristics is still unclear. This paper establishes a microscale simulation model of pin-plate DC positive and negative corona fluid chemical reactions. The phenomenon of positive and negative corona discharge is being investigated. The internal discharge mechanism is analyzed from the microscopic point of view. Results demonstrate that positive corona discharge generates space charges that reduce the electric field strength between the needle electrode and amplify it between the plate electrodes. In contrast, negative corona discharge exhibits the opposite effect. The number of charged particles produced by microscale negative corona discharge is larger than that produced by positive corona, and the discharge phenomenon is more intense than that of positive corona. Under the simulation conditions in this paper, the ionization reaction rate of micro-scale positive and negative corona rises rapidly at the initial discharge. It will gradually remain stable after experiencing an upward pulse. The pulse peak value generated by micro-scale negative corona discharge is much higher than that of positive corona, and the pulse width of negative corona discharge is about half smaller than that of positive corona, which can reach a stable corona discharge state faster.
Research on transmission line component detection based on scenario prior knowledge and knowledge distillation
Authors: Liu Shulin , Zhou Xue
Published: August 2024

Transmission lines for power systems are often located outdoors, which exposes them to various hazards that can seriously impact system reliability. Integrating UAV inspection and intelligent detection technology has emerged as a primary method for operational and maintenance tasks. However, challenges persist regarding detection accuracy and speed. This paper introduces a novel transmission line component detection approach, leveraging scene prior knowledge and knowledge distillation techniques. Initially, high-resolution aerial images of transmission lines are perceptually analysed. Subsequently, scene prior knowledge informs the selection of clustering algorithm parameters, enabling adaptive sub-region clustering and model optimization. Knowledge distillation is then applied to transfer comprehensive image feature knowledge from a teacher model to a student network, utilizing the obtained sub-regions as shared feature distillation masks. The efficacy of the proposed method is evaluated through extensive dataset analysis, demonstrating significant accuracy improvements ranging from 2.6% to 49.0% compared to alternative models.
Algorithm for detecting abnormal electricity usage by customers based on electricity big data and deep learning
Authors: Xu Hongwei , Wang Junrong , Liu Chaoxiang
Published: August 2024

In order to optimize the effect of individuals’ aberrant power utilization detection and reinforce the recognition rate and accuracy of abnormal power consumption detection of electricity use, an aberrant power utilization identification algorithm based on electric power big data and deep learning is proposed. Taking the two-way dialogue between power users and the power company as the basic perspective, real-time monitoring and collection of power consumption dynamics of users is carried out, and the power big data collection framework is designed. The retrieval of aberrant power utilization detection indexes is completed. Based on the deep learning algorithm, the artificial neural network base operation medium is combined to quantitatively solve the aberrant power utilization indexes, completing the design of a user aberrant power utilization detection algorithm. Experimental results show that the accuracy of the designed algorithm is 0.963, the F1 value is 0.985, and the AUC value is 0.942, which can effectively identify the aberrant power utilization and has a better performance of abnormal power consumption identification and detection.
Research on fault location method of active distribution network based on improved multiverse algorithm
Authors: Shang Liqun , Li Zhao
Published: August 2024

After the distributed power supply is connected to the distribution network, the network structure becomes more complex, and the fault characteristics change greatly compared with the traditional distribution network fault, so the original traditional fault location method is not satisfactory. This paper presents a fault location method for active distribution networks based on improved multi-node optimization (IMVO). According to the fault characteristics of the distribution network, the multiverse optimization algorithm is binary coded, and the algorithm parameters are improved to optimize the iterative process and enhance the performance of the algorithm. The simulation results show that this method can effectively solve the fault location problem of active distribution networks and has good advantages.
Mechanical properties of layered composites based on AA1050 and AA5056 aluminum alloys produced by WAAM technology
Authors: Evstifeev A D , Yakupov B A , Mavlyutov A M , Volosevich D V , Voropaev A A
Published: August 2024

The possibility of producing layered aluminum materials using wire-arc additive manufacturing (WAAM) technology has been investigated. Deformation characteristics of composites based on AA1050 and AA5056 aluminum alloys are considered. Mechanical tests of specimens with different orientations of AA1050 layers in AA5056 alloy matrix are presented. The results are analysed in the light of the structural characteristics of the composites.
Specificity of modeling the actuator for the deployment of transformable large-scale space structures
Authors: Zimin V N , Krylov A V , Shakhverdov A O
Published: August 2024

The creation of large-scale structures will be necessary for the development of information and transport space systems. Transformable systems form a distinct category of such space structures, designed based on automatic configuration changes. The transport and deployed operating states of transformable space systems can vary in dimensions by tens of times, with force actuators carrying out the deployment process. The optimal force actuator suitable for use in transformable space structures is an actuator comprising of active elements made of a titanium nickelide material with a shape memory effect, which has the ability to generate significant force, reliability, compactness, light weight and low power consumption. In the pursuit of developing large-scale transformable space systems, tremendous importance is placed on conducting full-scale experiments, which require costly equipment to be simulated in ground conditions. Therefore, an alternative option to verify the functionality of the large-scale transformable space system in development is through conducting a mathematical experiment utilizing the identifiable parameters of the developed computational models. Experimental and theoretical analyses of the active elements of the force actuator made of titanium nickelide material (1.5 mm diameter wire) have confirmed the fundamental possibility of creating a force actuator for opening large-scale transformable space structures.
The impact of energy sector pollution on human development and inequality amidst climate change
Authors: Rauner Sebastian , Piontek Franziska , Soergel Bjoern , Luderer Gunnar
Published: August 2024

The provision of energy is a primary contributor to climate change and environmental pollution, the latter including air pollution from aerosol emissions and a broad range of other human health effects and ecosystem damages. At the same time, aerosol emissions also reduce radiative forcing, leading to a masking of part of the warming due to rising CO2 concentrations and temporarily reducing the adverse impacts of climate change. Using an energy-economy-climate model linked to atmospheric chemistry, health impact and life cycle assessment models, we show that the societal costs of the health impacts of environmental pollution substantially exceed the economic benefits from masked warming. We further highlight the unequal burden of these issues on developing countries and explore the implications for human development, global inequality and international climate policy.