bluuebunny/crossref_metadata_2025 huggingface dataset:
A spectral force representation and its physical implication for vortex shedding past a stationary sphere
Authors: Lu Sheng-Sheng , Lin Lian-Yu , Lin Jen-Jen , Chang Chien-Cheng
Published: August 2024

In this study, we consider the connection of the hydrodynamic force with vortex shedding behind a stationary sphere in an unbounded fluid at several Reynolds numbers, covering the range of critical transition from plane-symmetric to non-symmetric flow. A principal spectrum analysis (PSA) is employed/proposed to obtain the spectral representation (SR) modes for each time-varying force coefficient; this enables us to identify (i) one single characteristic frequency at Re=300, 350, and 380, i.e., the fast frequency fVS which represents the frequency of vortex shedding and (ii) two characteristic frequencies at Re=390, 400, and 420: one is the first fast frequency f1=fVS, representing the frequency of vortex shedding, and the other is the second fast frequency f2, representing the frequency of side oscillations of the vortex flow in the transverse flow direction. In the situations of the latter set of Reynolds numbers, the SR modes indicate that not only the strength but also the phase of shed vortex varies slightly at each successive vortex shedding, and most notably, we have identified rotation of the vorticity pattern in the near wake about the central axis. The PSA-SR mode analysis reveals that these three vortex activities all co-operate at the integer multiples of the greatest common-divisor of the two characteristic frequencies (f1, f2). In other words, the intricate subtlety of vortex shedding behind a stationary sphere can well be uncovered through the PSA-SR mode analysis for establishing the close connections between the force coefficients and the vorticity activities behind the sphere. The present work represents a sequel to our previous study: A spectral force representation and its physical implication for vortex shedding past a stationary or an oscillating circular cylinder at low Reynolds numbers [Lu et al., “A spectral force representation and its physical implication for vortex shedding past a stationary or an oscillating circular cylinder at low Reynolds number,” Phys. Fluids 35(5), 053606 (2023)], where we initially proposed the PSA-SR analysis to establish the connections between the force coefficients and the vortex shedding of the circular cylinder under pre-, sub-, and normal synchronization.
Dynamics of bubble formation on superhydrophobic surface under a constant gas flow rate at quasi-static regime
Authors: O'Coin Daniel , Ling Hangjian
Published: August 2024

In this work, we experimentally studied bubble formation on the superhydrophobic surface (SHS) under a constant gas flow rate and at quasi-static regime. SHS with a radius RSHS ranging from 4.2 to 19.0 mm was used. We observed two bubbling modes A and B, depending on RSHS. In mode A for small RSHS, contact line fixed at the rim of SHS, and contact angle (θ) initially reduced, then maintained as a constant, and finally increased. In mode B for large RSHS, contact line continuously expanded, and θ slowly reduced. For both modes, during necking, contact line retracts, and θ was close to the equilibrium contact angle. Moreover, the pinch-off of bubble at the early stage was similar to the pinch-off of bubble from a nozzle and followed a power-law relation Rneck ∼ τ0.54, where Rneck is the minimum neck radius and τ is the time to detaching. Furthermore, we calculated the forces acting on the bubble and found a balance between one lifting force (pressure force) and two retaining forces (surface tension force and buoyancy force). Last, we found a waiting time for a finite volume to be detected for large RSHS. The detached volume was well predicted by Tate volume, which was derived based on balance between buoyancy and surface tension and was a function of bubble base radius.
Mechanism of multistability in chaotic maps
Authors: Liu Jin , Sun Kehui , Wang Huihai
Published: August 2024

This research aims to investigate the mechanisms of multistability in chaotic maps. The study commences by examining the fundamental principles governing the development of homogeneous multistability using a basic one-dimensional chain-climbing map. Findings suggest that the phase space can be segmented into distinct uniform mediums where particles exhibit consistent movement. As critical parameter values are reached, channels emerge between these mediums, resulting in deterministic chaotic diffusion. Additionally, the study delves into the topic of introducing heterogeneous factors on the formation of heterogeneous multistability in the one-dimensional map. A thorough examination of phenomena such as multistate intermittency highlights the intimate connection between specific phase transition occurrences and channel formation. Finally, by analyzing two instances—a memristive chaotic map and a hyperchaotic map—the underlying factors contributing to the emergence of multistability are scrutinized. This study offers an alternative perspective for verifying the fundamental principles of homogenous and heterogeneous multistability in complex high-dimensional chaotic maps.
Numerical investigation of fluid-thermal-structural interaction of deployable control fin in hypersonic flow
Authors: Thawait Amit Kumar , Tandaiya Parag , Jain Prakash C. , Chandy Abhilash J.
Published: August 2024

In this paper, a nonlinear aerothermoelastic analysis of a deployable control fin subjected to Mach 7 hypersonic flow is presented. The fin consists of the inboard and outboard parts joined together with a revolute joint having freeplay nonlinearity. The fin is assumed to be a whole movable fin and, hence, is connected to an actuator having nonlinear stiffness characteristics. The fin is made of the annealed Ti-6Al-4V material, which has temperature-dependent physical, mechanical, and thermal properties. To perform a coupled fluid-thermal-structural interaction analysis, a delayed detached eddy simulation method-based fluid dynamics solver is strongly coupled to a finite element method-based thermoelastic solver in the time domain. The effects of fin aspect ratio, thickness ratio, free stream dynamic pressure, and structural damping on the flow field as well as structural dynamics characteristics are investigated and presented. Since the flow is highly compressible at Mach 7 and the temperature rise is observed to be sufficient to excite the vibrational modes of the diatomic nitrogen and oxygen of the atmosphere, the air is modeled as a calorically imperfect gas. Shock interactions and concentrated vortices originating from various high-thickness locations at the joint as well as root sections are observed. It is found that at high altitudes, the contribution of the torsional mode is significant in fin deformation, whereas, at low altitudes, the bending mode contribution is higher. Also, it is shown that the fin aspect ratio, thickness ratio, and damping ratio have significant effects on the fin stability and performance.
Numerical study of the effects of fire on the flow and wake structures of an idealized building
Authors: Sun Yujia , Chen Qing , Zheng Shu , Liu Chao
Published: August 2024

Fire hazard is a crucial issue in urban arears. Fire plumes have large buoyancy forces and can significantly change the flow pattern around buildings. However, the interaction of these plumes with buildings under atmospheric boundary flow conditions has rarely been studied, and the effect on the wake characteristics of the buildings remains unclear. To investigate the interaction of fire with the wake flow around a building, the large-eddy simulation framework is used to simulate the flow and wake structures of an idealized cubic building. Fire is found to produce significant changes in the wake structures. In particular, fire leads to strong fire-swirl vortices near the trailing edges of the building and intense fire-plume vortices in the midair region downstream of the building. In the time-averaged results, a pair of tip vortices appears behind the top corners of the building and counter-rotating vortex pairs are observed downstream.
Memory and target payoff enhance cooperation in evolutionary social dilemmas
Authors: Lin Xinle , Li Jianhe , Fan Suohai
Published: August 2024

We proposed a neighbor selection mechanism based on memory and target payoff, where the target payoff is the maximum value of the group’s average expected payoff. According to this mechanism, individuals prioritize selecting neighbors whose average payoffs in the last M rounds are close to the target payoff for strategy learning, aiming to maximize the group’s expected payoff. Simulation results on the grid-based Prisoner’s Dilemma and Snowdrift games demonstrate that this mechanism can significantly improve the group’s payoff and cooperation level. Furthermore, the longer the memory length, the higher the group’s payoff and cooperation level. Overall, the combination of memory and target payoff can lead to the emergence and persistence of cooperation in social dilemmas as individuals are motivated to cooperate based on both their past experiences and future goals. This interplay highlights the significance of taking into account numerous variables in comprehending and promoting cooperation within evolutionary frameworks.
Demonstration of the multicaloric effect in a laboratory prototype
Authors: Amirov Abdulkarim , Samsonov Daniil
Published: August 2024

Using commercially available components, a compact laboratory-type prototype has been developed and assembled to demonstrate single and multicaloric effects arising from single and cyclic applications of magnetic fields and uniaxial mechanical loads. Using the example of the LaFe11.4Mn0.3Si1.3H1.6 alloy with a first-order phase transition near room temperature, the possibility of observing magnetocaloric, elastocaloric, and multicaloric effects is demonstrated. It is shown that by selecting protocols for applying combined external influences: magnetic field and mechanical load, it is possible to observe a synergistic effect for adiabatic temperature change, which amounts to 1.17 K (0.31 T and 19 MPa) at a temperature of 291.5 K for the multicaloric effect, which exceeds the corresponding value of |ΔT| = 0.75 K (0.31 T) at a temperature of 291.65 K for the magnetocaloric effect. The proposed approaches and obtained results can be used for the development of new prototypes of multicaloric cooling systems and the optimization of current ones.
5–13.5 μm broadband tunable long-wave infrared femtosecond laser
Authors: Liu Yunpeng , Qian Junyu , Feng Renyu , Li Wenkai , Li Yanyan , Peng Yujie , Leng Yuxin
Published: August 2024

We introduce a broadband tunable femtosecond laser source in the long-wave infrared (LWIR) band, covering the range of 5–13.5 μm, based on the integration of optical parametric amplification and difference frequency generation techniques. We utilize a dual-stage tuning method, combined with the high nonlinear coefficient and broadband phase matching range of the BaGa4Se7 crystal, to facilitate significant improvements in spectral coverage and energy efficiency. The laser yields a peak output energy of 43 μJ and maintains energies above 10 μJ across the entire tuning range, with an average power output exceeding 10 mW. The pulse duration at the central wavelength of 8.3 μm is measured at 72 fs full width at half-maximum using the electro-optic sampling method. This LWIR femtosecond laser can be used in many applications, such as molecular fingerprint spectral analysis, ultrafast chemical reaction spectral analysis, materials science, and ultrafast physics research, providing an important research basis for the generation and application of mid-infrared ultrafast laser sources.
Wave loads of bridge decks near a sloped beach
Authors: Chu Chia-Ren , Chen Meng-Hsien , Huynh Le Em , Wu Tso-Ren
Published: August 2024

This research is the first attempt to examine the hydrodynamic loads of nonlinear solitary waves on bridge decks near a coastline. We employ laboratory experiments and a large eddy simulation model to simulate the wave motion and wave loads on a partially submerged rectangular deck near a sloped beach. The measured wave heights and wave loads from wave flume experiments verify the accuracy of the computational fluid dynamics model. A series of parametric studies investigates the effects of wave height, submergence, and beach slope on the wave loads of the bridge deck. The simulation results revealed that the hydrodynamic forces are linearly proportional to the wave height, and the dimensionless force coefficients depend on the submergence ratio and beach slope. For the mild slope case (θ = 18.5°), the wave load during the run-up stage is larger than that during the run-down stage. The largest drag coefficient CD = 0.58, lift coefficient CL = 0.45, and pitch moment coefficient Cm = −0.21 occur when the deck is initially above the still wave level. On a steeper slope (θ = 30°), the run-down current could generate a large downward force and a clockwise moment when the bridge deck is close to a shoreline. Hereafter, coastal bridges should consider the impact of the run-down flow during tsunamis and storm surges.
Investigation of vacuum arc ignition characteristics and erosion morphology microstructure characteristics of CuCr55 electrode contact materials
Authors: Liu Siyuan , Bo Xianglai , Liu Zhiyuan , Geng Yingsan
Published: August 2024

Copper–chromium alloy material, as one of the most important electrode contact materials in the field of electrical contact, has been widely used in vacuum interrupters. To replace the SF6 circuit breakers at higher voltage levels and larger breaking capacities, there is an urgent need for new electrode contact materials to meet the comprehensive electrical performance requirements of high withstand voltage, high insulation, and erosion resistance. In this study, a novel electrode contact material, CuCr55, for a 252 kV single break vacuum interrupter was prepared by the arc melting method, and the microstructures of arc-cast CuCr25, melt-infiltrated CuCr50, and arc-melted CuCr55 materials were compared. The vacuum arc ignition and erosion characteristics of arc-melted CuCr55 contact materials were analyzed in detail. A high-speed camera was used to capture the arc ignition characteristics of short-circuit currents, and the critical currents for the formation of anode spots for different materials were obtained. The micro-morphology of the contact surface after erosion was observed using electron microscopy. The research results showed that the arc-melted CuCr55 contacts had a fine and uniform distribution of chromium particles with spherical and dispersed microstructures. After vacuum arc erosion, there was no material fracture or significant protrusion on the surface of CuCr55 contacts, and they exhibited a higher critical current for anode spot formation and good uniform erosion characteristics.
Disease as a constraint on goat production in Lao PDR and trade to neighbouring countries: a review
Authors: Jayasekara P. P. , Theppangna W. , Olmo L. , Xaikhue T. , Jenkins C. , Gerber P. F. , Walkden-Brown S. W.
Published: August 2024

Goat production in Lao People’s Democratic Republic (Lao PDR) is a small but rapidly growing sector owing to strong export demand, primarily from Vietnam. Disease has been identified as one of the major constraints to goat production but there are limited data on causes and effective control strategies. The situation is exacerbated by a lack of veterinary and extension services in rural areas. Information on the major disease and clinical syndromes of goats and their causative agents is needed to develop local and national control strategies and to improve animal welfare. Zoonotic diseases involving goats are also potentially important in terms of live goat trade and public health, albeit research is lacking. This review summarises and evaluates the available published data on caprine diseases in Lao PDR and provides possible disease control strategies to improve goat production in Lao PDR. Surveys and observations suggest that lip and facial dermatitis, eye conditions and diarrhoea are the most common clinical syndromes affecting the health of Lao goats. These clinical syndromes can be considered as priorities for Lao goats. Serological surveys conducted in limited geographical areas of the country have identified moderate seroprevalence of foot and mouth disease (FMD) and low seroprevalence of bluetongue, peste des petits ruminants (PPR), brucellosis and Q fever in goats. Accordingly, the clinical signs associated with the latter diseases were not commonly reported. Trichostrongylus spp., Haemonchus contortus and coccidia are the main gastro-intestinal parasites identified among Lao goats. Despite these studies, an understanding of the causation of the most common clinical syndromes in Lao goats is still lacking, similar to the situation in many other parts of Southeast Asia. Studies to determine the causation of common clinical syndromes need to be conducted in Lao goats if progress is to be made on overcoming the disease constraint. Similarly, studies are also needed to evaluate interventions that have been introduced to limit the impact of these disease and clinical syndromes. They will likely require changes to goat management and nutrition, in addition to disease-specific interventions.
Isopods on isopods: integrative taxonomy of Cabiropidae (Isopoda: Epicaridea: Cryptoniscoidea) parasitic on anthuroid isopods, with descriptions of a new genus and three new species from Japan
Authors: Shiraki Shoki , Kakui Keiichi
Published: August 2024

Species in the parasitic isopod family Cabiropidae are known to utilise various isopods as hosts but there are currently no records of members parasitising anthuroid hosts. We describe Anthuroniscus gen. nov. for three new cabiropid species, Anthuroniscus shimomurai sp. nov., Anthuroniscus dentatus sp. nov. and Anthuroniscus latus sp. nov., all of which are parasitic on anthuroid isopods. Anthuroniscus gen. nov. differs from the other 14 cabiropid genera and 10 genera treated as family incertae sedis in females having an elongate, dorsally compressed, posteriorly tapering body with six pairs of lateral bulges; and cryptoniscus larvae in the following combination of characters: (1) eyes lacking, (2) antennular article 1 with eight teeth on the posterior margin, (3) uropodal exopod and endopod rectangular rather than tapering, and endopod longer than exopod, and (4) pleotelson trapezoidal, 2× as wide as long. Anthuroniscus shimomurai sp. nov. was parasitic on Mesanthura sp. from Kaichu Doro, Uruma, Okinawa, south-western Japan; A. dentatus sp. nov. on Accalathura sp. from Irabu Island, Miyako Islands, Okinawa; and A. latus sp. nov. on Colanthura nigra from Kanagawa, central Japan. In pairwise comparisons, the three new species showed p-distances of 0.6–1.3% for the 18S rRNA gene (1440 positions); and A. shimomurai sp. nov. and A. latus sp. nov. showed a p-distance of 36.2% for the 16S rRNA gene (412 positions). In an 18S-based maximum-likelihood tree, an Anthuroniscus gen. nov. clade was the sister group to Cryptoniscoidea sp., parasitic on an ostracod species. This is the first study reporting Cabiropidae from Japan and anthuroids as hosts for Cryptoniscoidea. ZooBank: urn:lsid:zoobank.org:pub:2EE042E2-AE48-4B87-B495-8436462146B9
Diagnostic potential of blood plasma longitudinal viscosity measured using Brillouin light scattering
Authors: Illibauer Jennifer , Clodi-Seitz Tamara , Zoufaly Alexander , Aberle Judith H. , Weninger Wolfgang J. , Foedinger Manuela , Elsayad Kareem
Published: August 2024

Blood plasma viscosity (PV) is an established biomarker for numerous diseases. Measurement of the shear PV using conventional rheological techniques is, however, time consuming and requires significant plasma volumes. Here, we show that Brillouin light scattering (BLS) and angle-resolved spectroscopy measurements of the longitudinal PV from microliter-sized plasma volumes can serve as a proxy for the shear PV measured using conventional viscometers. This is not trivial given the distinct frequency regime probed and the longitudinal viscosity, a combination of the shear and bulk viscosity, representing a unique material property on account of the latter. We demonstrate this for plasma from healthy persons and patients suffering from different severities of COVID-19 (CoV), which has been associated with an increased shear PV. We further show that the additional information contained in the BLS-measured effective longitudinal PV and its temperature scaling can provide unique insight into the chemical constituents and physical properties of plasma that can be of diagnostic value. In particular, we find that changes in the effective longitudinal viscosity are consistent with an increased suspension concentration in CoV patient samples at elevated temperatures that is correlated with disease severity and progression. This is supported by results from rapid BLS spatial-mapping, angle-resolved BLS measurements, changes in the elastic scattering, and anomalies in the temperature scaling of the shear viscosity. Finally, we introduce a compact BLS probe to rapidly perform measurements in plastic transport tubes. Our results open a broad avenue for PV diagnostics based on the high-frequency effective longitudinal PV and show that BLS can provide a means for its implementation.
Bayesian image segmentation under varying blur with triplet Markov random field
Authors: Ouali Sonia , Courbot Jean-Baptiste , Pierron Romain , Haeberlé Olivier
Published: August 2024

In this paper, we place ourselves in the context of the Bayesian framework for image segmentation in the presence of varying blur. The proposed approach is based on Triplet Markov Random Fields (TMRF). This method takes into account, during segmentation, peculiarities of an image such as noise, blur, and texture. We present an unsupervised TMRF method, which jointly deals with the problem of segmentation, and that of depth estimation in order to process fluorescence microscopy images. In addition to the estimation of the depth maps using the Metropolis-Hasting and the Stochastic Parameter Estimation (SPE) algorithms, we also estimate the model parameters using the SPE algorithm. We compare our TMRF method to other MRF models on simulated images, and to an unsupervised method from the state of art on real fluorescence microscopy images. Our method offers improved results, especially when blur is important.
Gap distance sensing for non-magnetic medium based on magnetoelectric effect under spatial separation condition
Authors: Zhang Xiao , Xia Tian , Zhang Yahui , Yang Yikun , Yang Bintang
Published: August 2024

This paper presents a novel non-contact spatial gap distance sensing (GDS) method that can provide distance information in spatial separation conditions. In many applications, such as enclosed environments, it could not provide the desired measurement of gap distance of internal non-magnetic medium due to the constraints of physical barriers and poor accessibility. Therefore, a non-invasive sensing system is designed to measure spatial gap distance for non-magnetic medium. The developed sensor system consists of a pair of heteropolar permanent magnets (PMs), a non-magnetic medium, a magnetostrictive-piezoelectric composite unit and an external space, which has the function of spatial separation measurement. By exploiting the magnetoelectric effect, the magneto-machine-electric conversion is achieved by sensing the spatial magnetic field generated by the heteropolar PMs. The coupling modeling, analysis and calibration of sensing system are conducted, and the system prototype is designed and manufactured. Additionally, the performances of the GDS are experimentally validated. Static gap distance (plate thickness) measurements of the plate and variable gap distance (instant water height) measurements of water are performed, and resolution, vibration, and drift tests are carried out. The results show the accuracy and stability of non-contact spatial gap distance detection for non-magnetic medium, highlighting its potential in various applications.
Status and future directions for direct cross-section measurements of the 13C(a,n)16O reaction for astrophysics
Authors: Csedreki L , Gyürky Gy , Rapagnani D , Ciani G F , Aliotta M , Ananna C , Barbieri L , Barile F , Bemmerer D , Best A , Boeltzig A , Broggini C , Bruno C G , Caciolli A , Casaburo F , Cavanna F , Colombetti P , Compagnucci A , Corvisiero P , Davinson T , Depalo R , Di Leva A , Elekes Z , Ferraro F , Formicola A , Fülöp Zs , Gervino G , Guglielmetti A , Gustavino C , Imbriani G , Junker M , Lugaro M , Marigo P , Marsh J , Masha E , Menegazzo R , Paticchio V , Perrino R , Piatti D , Prati P , Robb D , Schiavulli L , Sidhu R S , Skowronski J , Straniero O , Szücs T , Zavatarelli S
Published: August 2024

The 13C(α,n)16O reaction is the main neutron source of the s-process taking place in thermally pulsing AGB stars and it is one of the main candidate sources of neutrons for the i-process in the astrophysical sites proposed so far. Therefore, its rate is crucial to understand the production of the nuclei heavier than iron in the Universe. For the first time, the LUNA collaboration was able to measure the 13C(α,n)16O cross section at E
c.m. = 0.23−0.3 MeV drastically reducing the uncertainty of the S(E)-factor in the astrophysically relevant energy range. In this paper, we provide details and critical thoughts about the LUNA measurement and compare them with the current understanding of the 13C(α,n)16O reaction in view of future prospect for higher energy measurements. The two very recent results (from the University of Notre Dame and the JUNA collaboration) published after the LUNA data represent an important step forward. There is, however, still room for a lot of improvement in the experimental study of the 13C(α,n)16O reaction, as emphasized in the present manuscript. We conclude that to provide significantly better constraints on the low-energy extrapolation, experimental data need to be provided over a wide energy range, which overlaps with the energy range of current measurements. Furthermore, future experiments need to focus on the proper target characterisation, the determination of neutron detection efficiency having more nuclear physics input, such as angular distribution of the 13C(α,n)16O reaction below E

α
< 0.8 MeV and study of nuclear properties of monoenergetic neutron sources and/or via the study of sharp resonances of 13C(α,n)16O. Moreover, comprehensive, multichannel R-matrix analysis with a proper estimate of uncertainty budget of experimental data are still required.
Intelligent mechanical fault diagnosis using multiscale residual network and multisensor fusion
Authors: Guo Haiyu , Yu Wei , Zhang Xiaoguang , Lu Fanfan , Liang Chuang
Published: August 2024

Mechanical faults in manufacturing systems need to be diagnosed accurately to ensure safety and cost savings. With the development of sensor technologies, data from multiple sensors is frequently utilized to assess the health of intricate industrial systems. In such cases, it is necessary to study the multisensor data based intelligent mechanical fault diagnosis method. First, the multisensor data is converted into grey images and then fused into a three-channel red-green-blue (RGB) image. Then, a multiscale with residual convolution module is proposed, which can extract multiscale deep features of the complex raw signal. Additionally, an attention module for channel and spatial attention is introduced to adaptively adjust the feature response values of each scale. Two datasets and a specific engineering application are used to validate the superiority of the network. The results show that the multisensor multiscale residual network outperforms other fault diagnosis networks in terms of fault identification accuracy, diagnostic efficiency, and applicability.
A method for obtaining cosmological models consistency relations and Gaussian Processes testing
Authors: Jesus J.F. , Escobal A.A. , Valentim R. , Pereira S.H.
Published: August 2024

In the present work, we apply consistency relation tests to several cosmological models,
including the flat and non-flat ΛCDM models, as well as the flat XCDM model. The analysis
uses a non-parametric Gaussian Processes method to reconstruct various cosmological quantities of
interest, such as the Hubble parameter H(z) and its derivatives from H(z) data, as well as the
comoving distance and its derivatives from SNe Ia data. We construct consistency relations from
these quantities which should be valid only in the context of each model and test them with the
current data. We were able to find a general method of constructing such consistency relations in
the context of H(z) reconstruction. In the case of comoving distance reconstruction, there were
not a general method of constructing such relations and this work had to write an specific
consistency relation for each model. From H(z) data, we have analyzed consistency relations for
all the three above mentioned models, while for SNe Ia data we have analyzed consistency relations
only for flat and non-flat ΛCDM models. Concerning the flat ΛCDM model, some
inconsistency was found, at more than 2σ c.l., with the H(z) data in the interval
1.8 ≲ z ≲ 2.4, while the other models were all consistent at this c.l. Concerning the
SNe Ia data, the flat ΛCDM model was consistent in the 0 < z < 2.5 interval, at 1σ
c.l., while the nonflat ΛCDM model was consistent in the same interval, at 2σ c.l.
Ultrasonic scalpel based on fusiform phononic crystal structure
Authors: Wang 王 Sha 莎 , Shan 单 Junjie 俊杰 , Lin 林 Shuyu 书玉
Published: August 2024

In response to the ultrasonic scalpels with the vibrational modal coupling which leads to a decrease in efficiency, an ultrasonic scalpel based on fusiform phononic crystals (PnCs) is proposed. An accurate theoretical model is constructed, which is mainly composed of electromechanical equivalent circuit models to analyze the frequency response function and the frequency response curves of the admittance. Bragg band gaps exist in the fusiform PnCs owing to the periodic constraint, which can suppress the corresponding vibrational modes. The vibration characteristics (vibration mode, frequency, and displacement distribution) of the ultrasonic scalpel are analyzed, and the validity of the electromechanical equivalent circuit method is verified. The results indicate that other vibration modes near the working frequency can be isolated. In addition, blades based on fusiform PnCs have a function akin to that of the horn, which enables displacement amplification.
Dzyaloshinskii–Moriya interaction and field-free sub-10 nm topological magnetism in Fe/bismuth oxychalcogenides heterostructures
Authors: Wang 王 Yaoyuan 垚元 , You 游 Long 龙 , Chang 常 Kai 凯 , Yang 杨 Hongxin 洪新
Published: August 2024

Topological magnetism with strong robustness, nanoscale dimensions and ultralow driving current density (∼ 106 A/m2) is promising for applications in information sensing, storage, and processing, and thus sparking widespread research interest. Exploring candidate material systems with nanoscale size and easily tunable properties is a key for realizing practical topological magnetism-based spintronic devices. Here, we propose a class of ultrathin heterostructures, Fe/Bi2O2
X (X = S, Se, Te) by deposing metal Fe on quasi-two-dimensional (2D) bismuth oxychalcogenides Bi2O2
X (X = S, Se, Te) with excellent ferroelectric/ferroelastic properties. Large Dzyaloshinskii–Moriya interaction (DMI) and topological magnetism can be realized. Our atomistic spin dynamics simulations demonstrate that field-free vortex–antivortex loops and sub-10 nm skyrmions exist in Fe/Bi2O2S and Fe/Bi2O2Se interfaces, respectively. These results provide a possible strategy to tailor topological magnetism in ultrathin magnets/2D materials interfaces, which is extremely vital for spintronics applications.
Model predictive current control of Dual Three-phase Permanent Magnet Synchronous Motor based on double virtual vectors
Authors: Yao Lei , Liu Weiting
Published: August 2024

Model Predictive Control (MPC) of traditional Dual Three-phase Permanent Magnet Synchronous Motor (DTP-PMSM) algorithm often uses a single virtual vector to suppress harmonics, but its vector range is limited, resulting in a large ripple in torque and current in the control effect. Given the aforementioned issues, this study suggests a Double Virtual Vector Model Predictive Current Control (DVV-MPCC) strategy. Utilizing the foundation of the virtual vector, a zero vector and the adjacent virtual vector are combined to construct an anticipated voltage vector, so that the output range of the synthetic vector can reach any amplitude and direction. By incorporating the deadbeat concept, the calculation of the action time for each virtual vector is precisely determined. Finally, the prediction model is employed to refine the value function, enabling the selection of the optimal expected vector for implementation on the inverter. The simulation outcomes demonstrate the effectiveness of the strategy in mitigating torque ripple and current ripple.
White Rabbit time synchronization of unmanned aerial vehicle cluster based on adaptive kalman filtering
Authors: Gao Zhaoqiang , Zhang Heng , Zhang Nan , He Jiazhou
Published: August 2024

Unmanned Aerial Vehicle Cluster (UAVS) necessitates precise wireless time synchronization to leverage its multi-node distribution. Traditional wireless time synchronization methods are constrained by the unpredictable wireless network environment, as well as factors like synchronization node maneuvering, resulting in suboptimal time synchronization accuracy. This paper addresses these challenges by proposing a self-adaptive time synchronization method for UAVS, based on the characteristics of the White Rabbit (WR) protocol. Utilizing Synchronous Ethernet (Sync-E), we synchronize time and frequency among multiple Unmanned Aerial Vehicles (UAVs) to ensure the stability of each UAV’s time source. Furthermore, an inverse adaptive Kalman filtering computation is applied for time synchronization technology, incorporating adaptive filtering to mitigate the impact of network jitter on synchronization accuracy. Experimental verification is conducted on the UAVS, demonstrating the improved accuracy and stability of the proposed method compared to the traditional WR time synchronization method.
Analysis of cracking causes of angle steel in 220 kV transmission tower
Authors: Fan Pingcheng , Xie Liming , Hao Qingyun , Chen Hao
Published: August 2024

An experimental analysis was conducted on the cause of cracking in the angle steel of a 220 kV transmission tower using macroscopic inspection, chemical composition analysis, microstructure inspection, and other testing methods. The results show that the angle steel did not have a groove before welding with the filler material at the notch bending position. Severe incomplete penetration defects were formed during the welding process, resulting in a large stress concentration at the defect site. This is the main reason for its corrosion and fracture. It is suggested to focus on checking for cracks during welding construction and strengthening the inspection of the welding quality of the angle steel of the transmission tower during the infrastructure stage for the bending part of the angle steel notch.
Effect of acoustic filler on sound insulation properties of millable polyurethane rubber
Authors: Han Xiao , Zhang Zhaoyang , Zhang Ling , Cheng Wei
Published: August 2024

Millable polyurethane (MPU) compound was prepared by mechanical blending with millable polyurethane as matrix material, hollow glass microspheres (HGM), and mica as acoustic fillers. Curing characteristics, mechanical properties, morphology, and damping capacity were characterized by a moving die rheometer, universal testing machine, scanning electron microscope (SEM), and thermomechanical analyzer. The results show that t90 has been shortened from 22 minutes and 33 seconds to 19 minutes and 46 seconds, ΔMH increased to 25.82 dN-m, the modulus increased, the maximum loss factor decreased, and the damping temperature range domain remained unchanged. The mechanical properties were better, the tensile strength was 20.5 MPa, the morphology was more complete, and the sound insulation was higher when HGM/mica content was 5/5 phr.
Interfacial morphology and reliability of GaN nanocomposite Sn-Ag-Cu lead-free braze joints
Authors: Liu Shaoxuan , Qu Min , Li Hang , Liu Yuan , Cui Yan
Published: August 2024

GaN nanoparticles, in varying mass fractions (0 wt%, 0.20 wt%, 0.40 wt%, 0.60 wt%, and 0.80 wt%), were integrated into a Sn-3.0Ag-0.5Cu lead-free solder using mechanical mixing followed by reflow soldering. The solders underwent isothermal aging at 170°C for different durations to assess the influence of GaN content on the melting characteristics, wettability, and growth behavior of the intermetallic compound (IMC) in the Sn-3.0Ag-0.5Cu solder. Findings indicate that GaN incorporation does not markedly alter the melting point of SAC305. However, a moderate GaN addition enhances the wettability of Sn-3.0Ag-0.5Cu, with the optimal effect observed at 0.40 wt% GaN, where the wettability is improved by 61.5% relative to the base solder. Furthermore, GaN addition serves to curtail the IMC layer’s growth, which, while it thickens with prolonged isothermal aging, does so at a rate governed by diffusion. At 0.40 wt% GaN, the diffusion coefficient is determined to be 1.453×10-15 m2/s, underscoring the superior performance of the novel SAC305-0.4GaN composite solder.
Research on the process of vertical water entry experiment of truncated cone-shaped projectile
Authors: Zhang Zhiyong
Published: August 2024

In order to study the influence of the diameter and velocity of the truncated head on the cavitation and motion characteristics of the projectile when it enters the water vertically, based on the high-speed camera method, the contrast experiment of the different diameter of the truncated head is carried out, and the influence law of the diameter and velocity of the head on the cavitation and motion velocity is obtained. The experimental results show that the velocity change law of the projectile in the deep closed state is basically the same, and the velocity change law in the process of turning the surface closed state begins to change; With the increase of the initial velocity of the projectile, the earlier the surface closure occurs, the earlier the separation of the cavitation from the tail cavity is, and the later the tail cavity contacts with the liquid surface; In the stage of surface closure, the general velocity rule of the projectile is: first increasing then decreasing, then increasing after smooth transition. When the velocity is high, the law of velocity changes to continuous decline.
Study on constitutive model and mechanical performance test simulation of 6082-T6 based on genetic optimization algorithm
Authors: Chen Suokun , Zhang Qinmin
Published: August 2024

Through the tensile test of 6082-T6 aluminum alloy sample, the mechanical properties parameters of the material (specified non-proportional tensile strength, tensile strength, elastic modulus E, elongation at break, proportional limit, Poisson’s ratio and strain hardening coefficient N) and the calculation method of strain hardening coefficient N of the constitutive model are analyzed and studied. A method of compiling a genetic algorithm (Ga) based on the Matlab platform to solve the hardening index of aluminum alloy materials is proposed. The results show that 6082-T6 aluminum alloy has good tensile strength and ductility, and the mechanical parameters are less than 3% compared with the national standard. The optimized algorithm is more stable than the traditional method in solving the hardening index n=21. The real stress-strain curve verifies the correctness of the obtained constitutive model, which can be used to predict the mechanical properties of aluminum alloy materials.
Split-tensile strength and micro-structure analysis of hybrid fibers coal gangue concrete
Authors: Li Jiuyang , Luo Jingwei , Fan Xinmei , Zhu Yuepeng , Wang Xiaoyu , Chen Li , Li Fan , Zhang Zicheng
Published: August 2024

To make the coal gangue better applied and engineered, through four factors (Coal gangue ceramicist [CGc] Substitution, coal gangue ceramic sand [CGs] Substitution, end-hooked steel fiber [SF], polypropylene fiber [PF]) four-level orthogonal test was conducted to explore the variation of Split-tensile strength of mixed-fiber coal gangue concrete and the strengthening mechanism of hybrid fiber on split-tensile strength of Coal-gangue concrete is analyzed from the microscopic point of view. The results show that the sequence of factors affecting the split-tensile strength is substitution rate of CGs > substitution rate of CGc > incorporation amount of SF > incorporation amount of PF. The optimal admixture combination is: CGc substitution rate of 30%, CGs substitution rate of 25%, SF incorporation rate of 1.00%, and PF incorporation rate of 0.2%. The spatial framework formed by hybrid fibers can enhance the stability of the ITZ to bond inner material tightly, thus enhancing the split-tensile strength of concrete.
Establishment and validation of mixed solid degenerate shell elements
Authors: Jin Xinlei , Qing Guanghui
Published: August 2024

Based on the generalized mixed variational principle, a 20-node generalized mixed degenerate shell element is proposed from the 20-node 3D spatial isoparametric element, and the basic assumptions of the plate and shell theory are introduced. Several typical examples are analyzed statically. In the case of the same finite element model, due to the introduction of stress boundary conditions, the result accuracy of the generalized mixed solid degenerate shell element is better than that of the conventional displacement element. The deflections of plate-shell structures with different thickness-to-span ratios are also analyzed, and the generalized mixed solid-degenerate shell element is insensitive to the span-to-thickness ratio. Numerical calculations result in stable convergence, reliability, and high accuracy.
Design Opportunities to Foster Independent Living: Insights from Working Age Persons with Disabilities from Thailand
Authors: Udomcharoenchaikit Pin , Kongchaimongkhon Warunyu , Areekit Poonsub , Bamroongvuth Atikarn
Published: August 2024

This paper explores design opportunities that could enhance the independent living experience of working-age individuals with disabilities in Thailand. It emphasizes the role of empathy in the design process, as it was the initial step in the design-thinking method. The empathy process was conducted under the phenomenological research in psychology method. The process involving in-depth interviews of working-age participants with mobility, visual, hearing, and cognitive impairments which are the majority of people with disabilities in Thailand. The sample included 10 participants with mobility impairments, 10 with visual impairments, 5 with hearing impairments, and 7 with intellectual impairments. They participated through self-selection (volunteer) sampling method. The findings of the study revealed key areas for improvement, including accessibility, technology, and social support. Participants expressed a desire for inclusive design solutions that prioritize ease of use, enrichment, and comfort. The paper highlights the importance of understanding, empathizing, and considering the needs and experiences of individuals with disabilities when designing products, services, and places. By doing so, designers across disciplines can develop more meaningful solutions that address their unique needs and challenges. The results of this research contribute to the ongoing conversation on designing for inclusivity and highlight the potential for design to positively impact the lives of individuals with disabilities. The limitations of this research were the use of volunteer sampling method may introduce selection bias, and the impact of Covid-19 outbreak could interrupt the interview result. Further studies might explore other demographics and delve deeper into areas like technology and social support to understand nuanced needs.
Spatial and Behavioural-based Adaptation Strategies of Residents Affected by the Rearrangement of Kampung METAL RW 01 Mojo towards Three Dwellings
Authors: Nugroho Dinan Nafindro , N. H. Kusumaningdyah , Hardiyati
Published: August 2024

The case of urban settlement with high poverty rates is a problem in various lower-middle countries that has yet to be resolved. The city’s inability to absorb the flow of urbanization resulted in the emergence of spontaneous settlements. To solve this problem, the KOTAKU (City Without Slums) program was launched which has been implemented since 2015. The city of Surakarta has determined the locations for urban settlements with high poverty rates with a total area of 359.53 hectares, in which there is the Semanggi Area which has an area of 76.03 hectares, so it is included in the handling priority list. To support the kampung planning program, a solution was devised for temporary housing or transitional housing for affected residents of Kampung METAL (Near Embankment) RW 01 Mojo arrangement with the planning and construction of the Sub-Komunal RISHA Semanggi housing. During this process, there is a process of spatial adaptation and habitual behaviour based on their occupation. Humans have always tried to maximize the function of buildings, which is why many ways of adaptation have been known. This research will provide an overview of the forms of adaptation processes and strategies for low-income communities affected by settlement arrangements. This study uses an interpretive paradigm. The research strategy used is qualitative and takes respondents with purposive sampling. The aspects studied in this research are the room program (building plans) in Kampung METAL RW 01 Mojo in 2018 compared to 2022, as well as the room program in the Sub-Komunal RISHA Semanggi housing which is complemented by testimonials of living experiences. Adaptation strategies that affected Kampung METAL RW 01 Mojo residents commonly use are adjustable, versatile, refitable and convertible. There are two forms of adaptation carried out by the affected residents: adaptation by adjustment and adaptation by reaction.