bluuebunny/crossref_metadata_2025_split huggingface dataset:
Instability of the cosmological DBI-Galileon in the non-relativistic limit
Authors: Leloup C , Heitz L , Neveu J 
Published: September 2023

Abstract
The DBI-Galileon model is a scalar-tensor theory of gravity which is defined as the most general theory of the dynamics of a 4D brane embedded in a 5D bulk. It is of particular interest as it introduces only a few free parameters, all with a clear physical meaning, such as the brane tension which is related to the cosmological constant. From the tight constraints on the gravitational waves speed, we are naturally led to consider the non-relativistic limit of the model where the kinetic energy of the brane is small compared to its tension, that we study in the context of late-time cosmology. We show that the Dirac–Born–Infeld-Galileon in the non-relativistic limit is an expansion around General Relativity which can be expressed as a shift-symmetric Horndeski theory. We develop the description of this theory at the background and perturbation level. However, by studying the scalar and tensor perturbations around a flat FLRW background, we find that they contain a ghost degree of freedom leading to a fatal instability of the vacuum for every combination of the free parameters. In order to avoid it in the more general cases of shift-symmetric Horndeski theories, we emphasize which of the Horndeski terms are in competition to produce this instability.
A fast analytical dose calculation approach for MRI-guided proton therapy
Authors: Duetschler Alisha , Winterhalter Carla , Meier Gabriel , Safai Sairos , Weber Damien C , Lomax Antony J , Zhang Ye 
Published: September 2023

Abstract

Objective. Magnetic resonance (MR) is an innovative technology for online image guidance in conventional radiotherapy and is also starting to be considered for proton therapy as well. For MR-guided therapy, particularly for online plan adaptations, fast dose calculation is essential. Monte Carlo (MC) simulations, however, which are considered the gold standard for proton dose calculations, are very time-consuming. To address the need for an efficient dose calculation approach for MRI-guided proton therapy, we have developed a fast GPU-based modification of an analytical dose calculation algorithm incorporating beam deflections caused by magnetic fields. Approach. Proton beams (70–229 MeV) in orthogonal magnetic fields (0.5/1.5 T) were simulated using TOPAS-MC and central beam trajectories were extracted to generate look-up tables (LUTs) of incremental rotation angles as a function of water-equivalent depth. Beam trajectories are then reconstructed using these LUTs for the modified ray casting dose calculation. The algorithm was validated against MC in water, different materials and for four example patient cases, whereby it has also been fully incorporated into a treatment plan optimisation regime. Main results. Excellent agreement between analytical and MC dose distributions could be observed with sub-millimetre range deviations and differences in lateral shifts <2 mm even for high densities (1000 HU). 2%/2 mm gamma pass rates were comparable to the 0 T scenario and above 94.5% apart for the lung case. Further, comparable treatment plan quality could be achieved regardless of magnetic field strength. Significance. A new method for accurate and fast proton dose calculation in magnetic fields has been developed and successfully implemented for treatment plan optimisation.
DE-UFormer: U-shaped dual encoder architectures for brain tumor segmentation
Authors: Dong Yan , Wang Ting , Ma Chiyuan , Li Zhenxing , Chellali Ryad 
Published: September 2023

Abstract

Objective. In brain tumor segmentation tasks, the convolutional neural network (CNN) or transformer is usually acted as the encoder since the encoder is necessary to be used. On one hand, the convolution operation of CNN has advantages of extracting local information although its performance of obtaining global expressions is bad. On the other hand, the attention mechanism of the transformer is good at establishing remote dependencies while it is lacking in the ability to extract high-precision local information. Either high precision local information or global contextual information is crucial in brain tumor segmentation tasks. The aim of this paper is to propose a brain tumor segmentation model that can simultaneously extract and fuse high-precision local and global contextual information. Approach. We propose a network model DE-Uformer with dual encoders to obtain local features and global representations using both CNN encoder and Transformer encoder. On the basis of this, we further propose the nested encoder-aware feature fusion (NEaFF) module for effective deep fusion of the information under each dimension. It may establishe remote dependencies of features under a single encoder via the spatial attention Transformer. Meanwhile ,it also investigates how features extracted from two encoders are related with the cross-encoder attention transformer. Main results. The proposed algorithm segmentation have been performed on BraTS2020 dataset and private meningioma dataset. Results show that it is significantly better than current state-of-the-art brain tumor segmentation methods. Significance. The method proposed in this paper greatly improves the accuracy of brain tumor segmentation. This advancement helps healthcare professionals perform a more comprehensive analysis and assessment of brain tumors, thereby improving diagnostic accuracy and reliability. This fully automated brain model segmentation model with high accuracy is of great significance for critical decisions made by physicians in selecting treatment strategies and preoperative planning.
Quantum droplets in one-dimensional Bose-Bose mixtures: beyond the Lee-Huang-Yang description
Authors: Boudjemâa Abdelâali , Abbas Karima 
Published: September 2023

Abstract
The static and dynamic properties of self-bound quantum droplets in a one-dimensional Bose-Bose mixture are discussed in the spirit of the Hartree–Fock-Bogoliubov theory. This latter enables us to provide beyond the Lee-Huang-Yang (LHY) quantum corrections to the equation of state at both zero and finite temperatures. In the uniform case our results for the ground-state energy and the critical temperature are confirmed through comparison with Quantum Monte-Carlo simulation and with available theoretical results. The density profiles are supported by numerical simulations of the generalized Gross-Pitaevskii equation which selfconsistently includes higher-order terms originating from the normal and anomalous fluctuations under the local density approximation. We show that the density exhibits a dip near its center in the flat-top plateau region for large interspecies interactions. We exemplify the impact of the beyond LHY corrections on the spatiotemporal evolution of the self-bound droplet in the presence of excitation induced by periodic density modulation. It is found that higher-order corrections may lead to the formation of a train of small droplets. We then extend our study for the case of inhomogeneous droplets in quasi one-dimensional Bose mixtures.
Influence of the Spatial Position of the Semi-open Impeller on the Internal Flow Field in Centrifugal Fans
Authors: Zhao Xintong , Guan Jianhui 
Published: September 2023

Abstract
This paper takes as its background the study of centrifugal fans in powered air-purifying respirators. To improve the efficiency of the centrifugal fan and the uniformity of the internal flow field, a steady-state simulation based on the realizable k-ε turbulence model, using the “frozen rotor method”, was carried out to analyze the effect of the spatial position of the impeller in the centrifugal fan on the internal flow field by matching the impeller to the worm gear. The results show that varying the eccentric angle, eccentric distance, and longitudinal depth of the semi-open impeller in the volute affects the internal flow field of the centrifugal fan to varying degrees. The concentric arrangement was not found to be optimal, and when the impeller rotates slightly further away from the worm tongue, the flow field inside the centrifugal fan is more uniform and the phenomena such as “wake-jet” and boundary layer separation are significantly reduced. In addition, it was found that the pressure distribution at the inlet is approximately the same as the pressure distribution in the flow field.
Preparation of CuO/g-C3N4 and its effect on the removal of phenol
Authors: Chao Lei , Chen Shiyuan , Sun Fang , Mo Xiaoyun 
Published: September 2023

Abstract
In this paper, CuO/g-C3N4 catalyst was prepared by one-step hydrothermal calcination, characterized, and analyzed by scanning electron microscope, X-ray diffraction, and X-ray photoelectron technology to test the activation effect and regeneration properties, and to investigate the effect of photocatalytic removal of phenol from the water after activation of sulfate with this material. A xenon lamp was used to simulate the visible light source, and the self-prepared phenol wastewater was used as the treated water sample to observe the treatment effect of the test under different test systems. The results show that the morphology of CuO/g-C3N4 and various energy peaks meet the requirements and have good photoactivation characteristics. The stability and recyclability of the catalyst were good, and the treatment of phenol reached 76 % after five tests. The phenol removal rate was 86.71 % at a reaction temperature of 40 °C, a catalyst dosage of 1 g/L, a persulfate concentration of 4 mM, and pH=5. In conclusion, CuO/g-C3N4 has a broad application prospect as a catalyst.
Lightweight Optimization of Garbage Collection Truck Manipulator Based on Parametric Modelling
Authors: Luo Li , Li Xucheng , Yuan Mingxin 
Published: September 2023

Abstract
In order to improve the performance of garbage collection truck manipulators, a three-dimensional model of the garbage collection truck manipulator is established based on SolidWorks. The dynamic analysis of the garbage collection truck manipulator model is carried out using the ADAMS software according to its movement in different working conditions, obtaining the displacement, force, and speed curves. The model is identical to garbage collection truck manipulators used in real situations. The static characteristics of the garbage collection truck manipulator model are analyzed in HyperWorks, which provides the conditions for the subsequent optimization. Finally, based on parametric modeling, taking the volume minimum as the goa, keeping the deformation and stress to meet the requirements for use as constraints, a genetic algorithm is used to optimize the weight of the manipulator. The optimization results show that the mass of the manipulator can be reduced by 17 kg (16.73%) while the strength meets the requirements.
Design and Characteristics of Shape Memory Alloy Bidirectional Torsional Actuator
Authors: Shen Chuanliang , Zhan Jincheng , Deng Yifei , Gao Yaohui 
Published: September 2023

Abstract
To overcome the problems of the low power/weight ratio of traditional servo motors, complex transmission systems, and large space occupied by hydraulic drive systems, this paper designs a bidirectional torsional actuator using the shape memory effect of Ti-Ni shape memory alloy (SMA) wire, which aims to realize the folding and unfolding of the wings of flying cars. The model of the designed actuator was established and the theoretical calculation was analyzed, based on which the experimental verification was carried out. It is found that when the heating current is 1.6 A, the mechanism can take into account the economy under the premise of meeting a certain folding speed. When the pre-stretching amount of SMA wire is 3%, the residual strain corresponding to the wire is small, about 0.577%, and it can provide driving torque and torsion angle to meet the design requirements of the actuator. This verifies the feasibility of the actuator and obtains the driving characteristics of the actuator. Finally, the shortcomings and improvement measures of the actuator are analyzed briefly.
Experimental study of the double-layer cylindrical shell under uniform axial pressure
Authors: Nie Luqing , Wang Lihui 
Published: September 2023

Abstract
In this paper, the buckling performance of the double-layer cylindrical structure with different layers of materials under uniform axial pressure is studied. Three identical double-layer and single-layer cylindrical thin shells are fabricated, measured, and tested respectively. The results indicate that the average ultimate strength of the double-layer cylinder is about 1.91 times that of the single-layer cylinder.
Oxide Inclusions in Aluminum-deoxidized Ultra-low CarbonSteel
Authors: Yang Chengwei , Liu Yi 
Published: September 2023

Abstract
RH (Ruhrstahl-Heraeus) degassing process was confirmed to be an effective method for making the steel cleaner by comparing the samples before and after RH degassing, mainly on the area of the total inclusion, the total number of inclusions, the mean area of inclusions, and inclusion size distribution. Four main types of inclusions including alumina and titanium oxides, and Al-Ti-O complex oxides were studied by analyzing their formation mechanisms, compositions, and morphology using SEM (scanning electron microscope) and EDS (energy-dispersive X-ray spectroscopy). Thermodynamic analysis through kinetic simulations of the different stages of RH degassing was conducted by the FactSageTM software package. Based on the equilibrium amount of oxides in the liquid steel, the effects of system temperature, oxygen contents, and alloy additions on the formation of inclusions and nozzle clogging were discussed to improve the steel’s cleanliness.
Tests and dynamic simulation analysis of an automatic instrument
Authors: Chen Qiangqiang , He Lei 
Published: September 2023

Abstract
To better study the dynamic characteristics of an automatic instrument and establish a realistic simulation model of automatic instruments, this paper has carried out movement tests of crucial parts under fixed conditions and recoil tests and collected the speed-time and recoil-time curves. Based on ADAMS software, the virtual prototype model of the key parts of the instrument is established, and the dynamic simulation is carried out. The different simulation results are separately compared with the experimental data, which verifies the accuracy of the recoil simulation model and provides a reference for the optimal design and improvement of the automatic instrument.
The synthesis of high-strength monolithic Al2O3-SiO2 aerogels through increased solid content and high-temperature calcination
Authors: Li Guoqi , Hu Li , Zhang Kai , Hou Sifan , Fan Jinpeng 
Published: September 2023

Abstract
High-strength Al2O3-SiO2 aerogels were synthesized by simultaneously increasing the solid content and high-temperature calcination. The effects of solid content and high-temperature calcination on mechanical properties, thermal conductivity, and microstructure of Al2O3-SiO2 aerogels were studied. The increase in solid content can improve the mechanical properties of aerogels. High-temperature calcination can further improve mechanical properties and reduce thermal conductivity. Finally, we fabricated a high-strength monolithic Al2O3-SiO2 aerogel with a high Young’s modulus of 127.45 MPa, room temperature thermal conductivity of 29.15 mW·m−1·K−1, and density of 252 mg·cm−3. This work is significant to the adhibition of Al2O3-SiO2 aerogels as high-strength thermal insulation materials.
Optimal Trajectory Planning Control for Quadruped Robot
Authors: Ren Dongyi , Cui Yushu 
Published: September 2023

Abstract
The posture information of the quadruped robot changes in real-time during its movement, and the trajectory planning method in view of trunk posture feedback is proposed. The kinematics equations of the mobile robot are built. The transformation matrix between the robot trunk posture and the foot-leg joint displacement is obtained. The feedback information of the body posture is integrated when planning motion trajectory. The motion trajectory of the robot according to the feedback information of the trunk posture is planned. The trajectories of the robot in the forward, lateral, and vertical directions are planned, respectively. The effectiveness and rationality of the optimal trajectory planning strategy are tested by the quadruped robot simulation platform.
Construction Method of Loop-Watt Mechanism Based on Watt Six-bars Units
Authors: Sun Xuemin , Yu Biao , Yu Zhiguo 
Published: September 2023

Abstract
In this paper, three Watt six-bar units are proposed to construct a loop connection mechanism (Loop-Watt mechanism) with a single degree of freedom (DOF) through the loop connection of rotating joints, and the constructed mechanism can complete the turnover motion. First of all, by analyzing the characteristics of the Watt six-bars unit and the theme idea of loop connection, the concrete method of loop connection is proposed, and the construction method of the Loop-Watt mechanism (LW-M) is obtained. Secondly, the DOF, motion forms, and motion characteristics of the Loop-Watt mechanism are analyzed, and its motion modes are obtained. Finally, the correctness of the analysis results is verified by establishing a 3D model in SolidWorks software. The Loop-Watt mechanism constructed in this paper is expected to have important application prospects in sealing mechanisms and large deployable mechanisms.
Research on automatic assembly technology of complex curved composite components
Authors: Zhang Tianzhu , Gao Aijuan , Wang Qi , Zhang Pin 
Published: September 2023

Abstract
Sophisticated composite materials have a range of outstanding broad merits such as high particular strength, high specific stiffness, powerful designability, excellent tiredness resistance, excellent durability, are widely used in transportation, medical, electronics and other area. The assembly process of the composite surface components has large assembly stress, which affects the assembly accuracy. At the same time, the manual assembly cycle is elongated, the efficiency is low, and the quality stability is impoverished, which constraints the assembly mass and assembly power of the complex curved composite components. To improve the assembly power and carry out automatic assembly, this paper designs the automatic assembly technology scheme of the complex curved composite components, designs the automatic assembly scheme verification device, and conducts the automatic assembly test to verify the feasibility of the scheme.
Study on Failure Mode of Cast Aluminum Alloy in Marine Environment
Authors: Li Xiangyu , Zhao Yapeng , Wang Yong 
Published: September 2023

Abstract
Aluminum alloy is an important metal material in the industrial field. With good mechanical properties, the ZL205A high-strength casting aluminum alloy has been widely used in aviation, aerospace, and other fields. In this paper, the erosion phenomenon of the ZL205A cast aluminum alloy on a certain type of marine equipment is described, and the failure mode of the ZL205A cast aluminum alloy in the marine environment is analyzed by simulation calculation and experimental verification. It provides technical support for the antierosion treatment and structural optimization of subsequent casting aluminum alloy equipment.
Analysis of cable eccentric diameter measurement based on the production line
Authors: Li Hongda , Jia Wentao 
Published: September 2023

Abstract
In order to meet the requirements of real-time monitoring and timely adjustment of cable diameter, a laser caliper is installed on the cable production line. Based on the laser diffraction measurement technology, the related laser diameter measuring instrument was developed. This equipment adopts a CCD array sensor and two mutually perpendicular pulse laser light sources, with a single exposure of only 0.1μs. It can identify the measuring objects with instantaneous changes, such as jittery workpieces, and obtain the outer diameter of the measured object through complex algorithm processing and relevant data calculation. The equipment is designed by relying on the laser diffraction measurement method and electromagnetic induction technology and using the CCD laser diffraction principle. In addition, the error can also be introduced into the linear array CCD image collector. TCD1703C is used for the linear array CCD, and the size length of each pixel is 7μm. If the measurement result is not processed by edge subdivision, the maximum measurement accuracy can only reach 7μm resolution.
Development and Research on Localization of Coal Machine Reducer Based on Reverse Engineering
Authors: Liu Xiaoxia 
Published: September 2023

Abstract
With the trend of localization of imported coal machine reducers being imperative, the traditional reducer development method has the problems of a high failure rate in the design stage, a long development cycle, and high manufacturing costs. Based on reverse engineering, this paper discusses the process of localization and development of imported coal machine reducers and focuses on the five steps from the reducer design stage. The determination of the boundary parameters of the reducer, the acquisition of the surface data and performance data of the reducer parts, the three-dimensional modeling, the virtual assembly, and the interference inspection are analyzed. This paper summarizes the key technologies of the localization development of the reducer and forms an effective method for the localization development of the imported coal machine reducer. Finally, the feasibility and effectiveness of the localization development method of the reducer are verified by an example.
Harnessing of the low energy wind potential
Authors: Iliev R , Tsalov Ts 
Published: September 2023

Abstract
This paper analyzes the wind energy parameters for different areas with low wind energy potential using the data from the global online wind map. The performance characteristics of different types of wind turbines are reviewed. The generated theoretical electric energy within one year for 9 types of wind turbines is presented. Suitable wind turbines for harnessing low wind potential, that can cover the electrical needs of one household are proposed.
A possibility of harnessing the heat discarded into the environment using thermoelectric generators.
Authors: Danca Paul Alexandru , Babutanu Corina , Bunea Florentina , Dogeanu Angel 
Published: September 2023

Abstract
Energy demand from the last decade combined with the requirement of lowering pollutant emissions, created the need to harvest energy which normally is not used. Some of the harvesting elements are thermoelectric generators which have become used nowadays. The purpose of this study is to use thermoelectric generators, to capitalize heat release in nature by an air conditioning system. An experimental study was concluded and the mean temperature difference Δt between the hot and cold source was 70°C. According to a chosen thermoelectric module, the energy produced at this Δt is around 1.85W.
Research of the energy parameters of the most demanded wood biomass pellets on Bulgarian market
Authors: Murzova M , Zlateva P 
Published: September 2023

Abstract
The following research focuses on exploring the energy parameters of the most demanded wood biomass pellets on the Bulgarian market. To assess the accuracy and reliability of the information provided on the packaging of wood pellets, a comparative analysis was conducted. The initial step involved conducting experimental tests to determine the energy characteristics of the most demanded brands of waste wood raw materials, as reported by the surveyed customers. These parameters included diameter, calorific value, ash content, and moisture content. By comparing the data obtained from the experiments with the information stated on the packaging, it was observed that all analysed parameters met the requirements outlined in the ENplus quality certificate. Additionally, the results confirmed that the wood pellets belonged to class A1, indicating their high quality and adherence to the specified standards.