bluuebunny/crossref_metadata_2025 huggingface dataset:
A new frequency domain denoising method for coal mine transient electromagnetic measuring data
Authors: Huang Maolin , Tang Yu , Zhang Jiaqi , Yu Jingcun , Su Benyu , Li Z
Published: October 2024

Due to limitation of space in mine tunnel, only a 2 m × 2 m rectangle coil can be employed to collect the electromagnetic signals for the mine transient electromagnetic analysis. Hence, a small emission magnetic moment and weak detection signal strength will increase the electromagnetic analysis difficulty. Moreover, the transient electromagnetic response signal in mines exhibits exponential decay over time, with late-stage amplitudes being notably small, which makes these signals susceptible to noise interference. As a result, it is necessary to study effective noise removal methods to enhance the signal-to-noise ratio of the late-stage electromagnetic data. Addressing this challenge task, this study proposes a new method for frequency domain denoising of transient electromagnetic data. This new method utilizes the Fourier Transform to convert the original transient electromagnetic data from the time domain to the frequency domain, and then, the noise is identified and removed through the frequency characters. Lastly, the processed frequency domain information is transformed to the time domain by the Fourier Inverse Transform to restore the time domain signals. The effect of this frequency domain denoising method is demonstrated through numerical simulations and underground coal mine field data to show significant noise reduction performance on the abnormality detection in the underground coal mine.
DeepLPos: a comprehensive hybrid deep learning model for lying position recognition using a tactile sensor array system
Authors: Song Yao , Guo Shijie , Liang Bowen
Published: October 2024

Unpredictable limb movements or turning motions can significantly disrupt the accurate extraction of physiological signals, such as respiratory and heart rates. In clinical environments, reliable detection of lying positions is crucial for continuous patient monitoring, particularly during sleep. In this paper, a smart sleeping position recognition system is proposed, which employs a tactile pressure sensor array based on the unique structure of ‘the electrostatic double-layer capacitors’. The sensor array, comprising 64 rows and 32 columns (2048 nodes), captures four types of healthy lying positions using an 8-bit AD module. Despite challenges arising from limited experimental samples for accurate training, we propose DeepLPos, a hybrid deep learning approach combining generative adversarial networks and the you only look once network. To tackle the differentiation challenge between supine and prone positions, we introduce an SPD Conv attention module to enhance the resolution of detailed descriptions in pressure images. The model is further pruned to optimize both structure and parameters, enabling efficient real-time detection. Evaluated on the SLP dataset, the proposed system achieves an accuracy of 97.5% with a real-time processing speed of 0.069 s per frame, demonstrating its potential for practical, high-precision measurement and monitoring applications in healthcare.
Algebraic calming for the 2D Kuramoto-Sivashinsky equations
Authors: Enlow Matthew , Larios Adam , Wu Jiahong
Published: October 2024

We propose an approximate model for the 2D Kuramoto–Sivashinsky equations (KSE) of flame fronts and crystal growth. We prove that this new ‘calmed’ version of the KSE is globally well-posed, and moreover, its solutions converge to solutions of the KSE on the time interval of existence and uniqueness of the KSE at an algebraic rate. In addition, we provide simulations of the calmed KSE, illuminating its dynamics. These simulations also indicate that our analytical predictions of the convergence rates are sharp. We also discuss analogies with the 3D Navier–Stokes equations of fluid dynamics.
Laser-initiated electron and heat transport in gold-skutterudite CoSb3  bilayers resolved by pulsed x-ray scattering
Authors: Plech Anton , Gaal Peter , Schmidt Daniel , Levantino Matteo , Daniel Marcus , Stankov Svetoslav , Buth Gernot , Albrecht Manfred
Published: October 2024

Electron and lattice heat transport have been investigated in bilayer thin films of gold and CoSb3  after photo-excitation of the nanometric top gold layer through picosecond x-ray scattering in a pump-probe setup. The kinetics of heat transfer are detected by thermal lattice expansion and compared to simulations based on the two-temperature model of coupling of electron and phonon degrees of freedom. The unexpected observation of a larger portion of the deposited heat being detected in the underlying CoSb3  layer before the topmost gold layer is heated supports the picture of transport of the photo-excited electrons from gold to the underlying layer to be converted into lattice heat. The change of partition of heat between the gold and CoSb3  layer with laser fluence and wavelength (either exciting intraband transitions or additionally interband transitions) is rooted in the amplitude of electron temperature. Higher electron temperatures result in a longer equilibration time with the lattice and thus a larger proportion of ballistic electron transport across the interface.
Vacuum entanglement probes for ultra-cold atom systems
Authors: Gooding Cisco , Sachs Allison , Mann Robert B , Weinfurtner Silke
Published: October 2024

This study explores the transfer of nonclassical correlations from an ultra-cold atom system to a pair of pulsed laser beams. Through nondestructive local probe measurements, we introduce an alternative to destructive techniques for mapping Bose–Einstein Condensate (BEC) entanglement. Operating at ultra-low temperatures, BEC density fluctuations emulate a relativistic vacuum field. We show that lasers can serve as Unruh–DeWitt detectors for vacuum BEC phonons. A quantum vacuum holds intrinsic entanglement, transferable to distant probes briefly interacting with it—a phenomenon termed ‘entanglement harvesting’. Our study accomplishes two primary objectives: first, establishing a mathematical connection between a pair of pulsed laser probes interacting with an effective relativistic field and the entanglement harvesting protocol; and second, to closely examine the potential and persisting obstacles for realising this protocol in an ultra-cold atom experiment.
Transmission enhancement mechanism of PT symmetric photonic crystal coupled with grooved sub-wavelength grating
Authors: Chen Ying , Shi Moqing , Zhao Meng , Cui Dongyan , Wang Qinghui , Zhao Guoting , Li Weiqiang
Published: October 2024

In order to enhance the sensing characteristics of the sensor, based on the periodic sub-wavelength grating(SWG), a groove structure is introduced to make the Fano resonance waveform sharper. At the same time, based on the Parity-Time(PT) symmetry principle, by making the periodic photonic crystal meet the PT symmetry condition, the structure can absorb the energy of the emitted light on the original basis, produce the transmission enhancement effect, and make the transmission peak of the structure exceed 1. The sensing is realized by using the property that the different refractive indices of the detected medium corresponds to different transmission. When the incident light is 1550 nm, the sensitivity and FOM (Figure of Merit) value of the proposed structure reach 5.702 × 105RIU−1and 1.9 × 107 respectively, which greatly improves the performance of the sensor.
A space-time meshfree method for heat transfer analysis in porous material
Authors: Lin Yuanjian , Wang Fuzhang
Published: October 2024

Porous material batteries are a new type of battery technology that uses porous materials as electrode materials, with advantages such as long lifespan. In the present study, we manily propose a space-time meshfree method for heat transfer problems in porous material energy storage battery. The thermal behavior is demonstrated based on a numerical solution of the energy conservation equation. A simple space-time meshless collocation scheme, which is based on a new type space-time radial basis function, is presented to get the approximate solution of the energy conservation equation. The energy conservation equation was transferred into a system of linear algebraic equations. By introducing prescribed boundary conditions, the heat transfer analysis in porous material energy storage battery can be shown with numerical results. Numerical discussions show that the proposed meshless collocation method is appropriate to simulate thermal behavior in porous material energy storage battery, while the traditional finite element method failed to provide the reasonable results for the tested examples in this paper.
Switchable phase modulation and multifunctional metasurface with vanadium dioxide layer
Authors: Su Mingzhu , Wang Xufeng , Mu Kaijun , Fan Chunzhen
Published: October 2024

Metasurface, comprising subwavelength unit cells, offers a flexible modulation of the optical phase. However, traditional metasurfaces are typically engineered to function solely in one mode, limiting their efficiency and adaptability. In this study, we proposed a switchable metasurface consisting of gold bars deposited on polyimide and vanadium dioxide (VO2) layer. Upon the phase transition of VO2, this switchable metasurface exhibits functionality in both transmissive and reflective modes. Specifically, it efficiently converts left circularly polarized (LCP) light into right circularly polarized (RCP) light. For the dielectric (metallic) phases of VO2, the design behaves as metalens with a focal length of 1000 (906) μm at working frequency of 1.2 THz, respectively. Furthermore, the vortex phase can be effectively manipulated with topological number from 1 to 4 through the analysis of the electric field distribution. A directional emission from 12.9° to 42.2° is obtained in the reflective mode and Airy beam paths way can also be well regulated at 1.49 THz. The phase modulation is further achieved by varying the inter-mediums and its thickness. Finally, the sensing ability is explored with different covered solution. Consequently, this multifunctional and adaptable metasurface offers valuable insights for the development of reflectors, modulators, lenses and sensors.
Unveiling half-metallic, thermoelectric and optoelectronic behavior of the new Heusler alloy RbCrZ (Z = Si, Ge): a DFT perspective
Authors: Gurunani Bharti , Gupta Dinesh C
Published: October 2024

Utilizing the density functional theory (DFT) method, this study aims to predict with precision the structural, elastic, electronic, magnetic, thermoelectric, thermal, and optical properties of two recently discovered half-Heusler alloys, namely RbCrSi and RbCrGe. The exchange and correlation potential are accounted for using the generalized gradient approximation of Perdew–Burke–Ernzerhof (GGA-PBE) and the Tran–Blaha-modified Becke–Johnson exchange potential (TB-mBJ). Through structural analysis, it is observed that both RbCrSi and RbCrGe alloys exhibit energetic stability in a type-3 structure with a ferromagnetic (FM) state. Both alloys exhibit half-metallic properties and integer magnetic moments of 3 μB, following the Slater-Pauli rule. Additionally, elastic calculations confirm their mechanical stability and anisotropic ductile behavior. The quasi-harmonic Debye model (QHDM) is employed for calculating thermodynamic properties, while the BoltzTraP code, based on semi-classical Boltzmann theory (SCBT), is utilized for evaluating thermoelectric properties. Findings reveal that RbCrZ alloys (with Z = Si, Ge) exhibit high figure of merit (ZT) values nearing unity at highest temperature. Consequently, the newfound half-Heusler alloys RbCrSi and RbCrGe hold significant promise for applications in thermoelectricity and spintronic devices. This comprehensive analysis underscores the potential of these alloys in the realm of renewable energy applications.
Aluminum doped zinc oxide as UV laser-based nanothermometer
Authors: Azmi Atiqah Nabieha , Wan Ahmad Kamil Wan Maryam , Halim Mohd Mahadi , Wan Ismail Wan Zakiah
Published: October 2024

This work explores thermal laser-based nano-sensing capabilities utilising random lasing emission obtained from zinc oxide (ZnO) nanorods prepared by chemical bath deposition. The ZnO nanorods were doped with Aluminum (Al) at a concentration of 10 mM by using a simple dip method for several dip durations of 20 s, 30 s, 40 s, 60 s, 80 s, and 100 s, respectively. Random lasing emission was observed in all samples and was tested on its thermal sensitivity from the increased heat of the nanorod structure. The highest thermal sensitivity of 0.001 °C−1 was obtained from Al-doped ZnO nanorods that were dipped for 60 s. The lasing threshold was 22.92 mJ cm−2 and the lasing spectral width was 1.16 nm.
High-throughput screening of the potential alloying elements for high-strength Mg alloys based on solid-solution strengthening
Authors: Zhou Fei , Huang Jingtao , Liao Mingqing , Xu Chao
Published: October 2024

49 types of alloy atomic dopants and their effects on the doping stability and micro-mechanical behaviour of magnesium matrix were investigated using density functional theory and high throughput first-principles calculations. Geometry optimization was performed for each doping system, and the ability of atom doping into the magnesium matrix was assessed based on the doping energy and atomic radius. Results show that the transition metal elements have negative or near negative doping energy, especially for the elements with a radius that similar to Mg. The micro-mechanical properties of the doping system were evaluated by computing the fracture energy and theoretical tensile stress. Through a screening on the doping stability and strengthening effect of 49 types of alloy atoms, a set of elements (Re, Os, Ir, Tc and W, etc) are screened out that could strengthen the magnesium matrix with a good doping stability. The high throughput screen results serve as a theoretical guide for the selection of appropriate alloy elements for designing the high-strength magnesium alloys in the regime of solid solution strengthening effects.
Enhanced optoelectronic characteristics of La-doped ZnO and its compatibility with Cs-doped MAPbI3 perovskite absorber material
Authors: Tabriz Ayesha , Shahzad Nadia , Pervaiz Hina , Shahzad Muhammad Imran , Nadeem Saad , Mehmood Sana , Ali Ghulam , Iqbal Naseem , Pugliese Diego
Published: October 2024

The present study investigates the structural, electrical and optical characteristics of pristine and lanthanum (La)-doped zinc oxide (ZnO) electron transport layers fabricated by the sol–gel method and their compatibility with Cs0.10MA0.90Pb(I0.9Br0.10)3 absorber layer for perovskite solar cells. All the electron transport layers were deposited under the same deposition conditions, with the only difference in La percentage in the precursor solutions, ranging from 0 to 6%. X-ray diffraction analysis demonstrated the presence of crystalline ZnO thin films and the absence of any impurity phases after La-doping. The calculated crystallite size, determined using Scherrer’s equation, increased from 11.13 to 21.76 nm after the introduction of dopant. The doping with 4% La led to the decrease in the optical band gap from 3.32 eV of pristine ZnO to 3.23 eV. Scanning electron microscopy analysis revealed better morphology of perovskite / 4% La:ZnO specimen, which facilitated the absorbance and reduced the charge carrier recombination. It also exhibited superior resilience towards moisture and humidity which will eventually contribute to the development of more stable and efficient planar perovskite solar cells.
Comprehensive study on the optoelectronic properties of ZnSnP2 compound by DFT and simulation for the application in a photodetector
Authors: Pappu Md Alamin Hossain , Mondal Bipanko Kumar , Shiddique Sheikh Noman , Hossain Jaker
Published: October 2024

This article presents the density function theory (DFT) calculation of ZnSnP2 (ZTP) and its application as a photodetector. A DFT calculation has been performed to determine ZTP’s optical and electronic characteristics. The direct bandgap of ZnSnP2 is found to be 1.0 eV which agrees well with the previously reported bandgap (0.95 eV). The total density of states (TDOS) of ZTP is determined to be 1.40 states/eV which is attributed to the 3p orbital of P, with minor impacts from the 3d orbital of Zn and the 5p orbital of Sn to TDOS. The real and imaginary dielectric functions and refractive indices ZTP have been determined to be 16.44 and 17.60, 4.07 and 2.92, respectively. The absorption coefficient and reflectivity of ZTP obtained from this investigation are 2.6 × 105 cm−1 and 57.5%, respectively. After calculating the electrionic and optical properties, ZTP-based n-CdS/p-ZnSnP2/p+-AlSb photodetector (PD) with CdS and AlSb as the window and back surface field (BSF) layers, respectively, has been computationally analyzed and optimized using solar cell capacitance simulator (SCAPS-1D). In a single heterojunction, the photocurrent, voltage, responsivity, and detectivity values have been obtained at 44.52 mA cm−2, 0.66 V, 0.73 A W−1, and 6.81 × 1013 Jones, respectively. Insertion of a thin AlSb BSF layer improves the photocurrent, voltage, responsivity, and detectivity to 48.75 mA cm−2, 0.78 V, 0.86 A W−1, and 8.22 × 1014 Jones, respectively. The outcomes are highly promising for the fabrication of a high performance ZTP-based PD in the future.
Ensemble Learning for Stellar Classification and Radius Estimation from Multimodal Data
Authors: Deng Zhi-Jie , Yu Sheng-Yuan , Luo A-Li , Kong Xiao , Li Xiang-Ru
Published: October 2024

Stellar classification and radius estimation are crucial for understanding the structure of the Universe and stellar evolution. With the advent of the era of astronomical big data, multimodal data are available and theoretically effective for stellar classification and radius estimation. A problem is how to improve the performance of this task by jointly using the multimodal data. However, existing research primarily focuses on using single-modal data. To this end, this paper proposes a model, Multi-Modal SCNet, and its ensemble model Multimodal Ensemble for Stellar Classification and Regression (MESCR) for improving stellar classification and radius estimation performance by fusing two modality data. In this problem, a typical phenomenon is that the sample numbers of some types of stars are evidently more than others. This imbalance has negative effects on model performance. Therefore, this work utilizes a weighted sampling strategy to deal with the imbalance issues in MESCR. Some evaluation experiments are conducted on a test set for MESCR and the classification accuracy is 96.1%, and the radius estimation performance Mean of Absolute Error and σ are 0.084 dex and 0.149 R
⊙, respectively. Moreover, we assessed the uncertainty of model predictions, confirming good consistency within a reasonable deviation range. Finally, we applied our model to 50,871,534 SDSS stars without spectra and published a new catalog.
Pedestal dynamics and turbulence in H-mode density ramp-up experiment on EAST
Authors: Zhong Fubin , Zhang Tao , Li Gongshun , Geng Kangning , Ye Kaixuan , Yang Shuqi , Zhou Zhen , Zhou Ziqiang , Yu Lin , Huang Jia , Wen Fei , Gao Xiang ,   the EAST Team
Published: October 2024

Recent results of density ramp-up (<n
e>/n
GW = 0.5–0.75) experiment in type-I ELMy H-mode on experimental advanced superconducting tokamak are presented, with a focus on pedestal dynamics and turbulence behavior. With the density increase, a general trend is that the pedestal electron pressure (p
e
ped) decreases while the ELM frequency (f
ELM) increases. Especially when <n
e>/n
GW arrives at ∼ 0.68, a sudden decrease of p
e
ped and an increase of f
ELM are observed. A quasi-coherent mode (QCM) with a frequency of 200–300 kHz is observed in the pedestal region and appears in both density and magnetic fluctuations. The time evolution of p
e
ped during the inter-ELM phase is analyzed for different densities. The analysis suggests that the pedestal behavior for <n
e>/n
GW < 0.68 is mainly attributed to pedestal stability but not due to pedestal transport. It is shown that the resistivity effect on the peeling-ballooning (PB) mode (Zhang et al 2017 Phys. Plasmas
24 062108) could be used to explain the present result. But the sudden decrease of p
e
ped and increase of f
ELM at <n
e>/n
GW > 0.68 cannot be attributed to the resistivity effect. It is found that for the plasma with <n
e>/n
GW > 0.68, the QCM disappears just before ELM and the density pedestal becomes steeper. This implies that the QCM can drive outward particle transport. The steeper density pedestal leads to a narrower pedestal width. A narrower pedestal width will lead to a lower pedestal pressure since PB mode limits the pressure gradient and could explain the observed sudden decrease of p
e
ped and increase of f
ELM.
Impact of hot plasma effects on electron cyclotron current drive in tokamak plasmas
Authors: Zheng P.W. , Feng J.L. , Lu L.F. , Yin L. , Huang Q.H. , Gong X.Y. , Zhang F. , He L.H. , Zhong Y.J.
Published: October 2024

Focusing on the impact of hot plasma effects on electron cyclotron current drive (ECCD), this paper presents the numerical results of top launch ECCD (TL-ECCD) and outside midplane or equatorial-plane launch ECCD (EL-ECCD) in the HL-3-like tokamak plasmas. For EL-ECCD, there is little difference in the calculated results under the cold and hot plasma propagation models, and the results are not affected by the dominant current drive mechanism of EC waves. In the cases of TL-ECCD, the large initial parallel refraction makes the influence of hot plasma effects on ECCD become significant. In the range of toroidal magnetic fields B
T discussed in this paper, the difference between the calculated results under the two propagation models rapidly decreases as the value of B
T decreases, and the difference between the two is already very small in the range of 1.8 T ⩽ B
T ⩽ 2.0 T. Therefore, the influence of hot plasma effects can also be neglected for TL-ECCD, and the cold plasma propagation model can be directly adopted. For the HL-3-like tokamak equipped with a dual-frequency EC wave system at 140 GHz and 105 GHz, if the addition of a TL-ECCD is considered in the existing outside midplane and upper launch manners, through appropriate combination of 140 GHz TL-ECCD and dual-frequency outside EL-ECCD, the ECCD can be used in a larger B
T window (1.8 T ⩽ B
T ⩽ 2.25 T) and a wider radial range (0.1 ⩽ ρ ⩽ 0.8–0.9) to generate current efficiently. The normalized current drive efficiency of the TL-ECCD is nonlinear with the injected EC power, it reaches the maximum at the injected power of 6–8 MW. This is of significance for the stable operation of HL-3-like tokamak with high plasma current above 1 MA.
Influence of γ-radiation on magnetoelectrical properties of Bi0.85Sb0.15  (0.001≤x≥0.05) solid solution
Authors: Tagiyev M.M. , Abdullayeva I.A. , S.G Jafarova
Published: October 2024

The influence of γ-quantum on the magnetoelectric properties of Bi0.85Sb0.15  (0.001≤x≥0.05) thermoelectrics doped with lead atoms at ~77÷300K and magnetic field induction up to 1.0 Tesla has been studied. It was found that at low doses of gamma irradiation of the Bi0.85Sb0.15  solid solution, point defects are formed, which lead to an increase in the concentration of free electrons n, specific electrical conductivity σ and a decrease in the absolute value of the thermo EMF coefficients α and RH. As the dose of γ-quanta increases in the process of subsequent restructuring, point defects accumulate, i.e. accumulation of point defects, which leads to a decrease in the concentration of current carriers and a corresponding change in σ, α. and RH.
Design Verification and Performance Testing of Container Valves for Offshore 30Mpa IG541 Fire Extinguishing System
Authors: Shining Yuan , Guanglei Lv , Haichen Wang , Xiang Gao , Jun Chen
Published: October 2024

Addressing the challenges of large space occupation, limited transmission distance, and suboptimal fire extinguishing efficiency of the current 15Mpa IG541 gas fire extinguishing system commonly found on offshore oil production platforms and ships, especially in deepwater facilities where stringent requirements exist for both transmission distance and environmental performance. Increasing the storage pressure can enhance space efficiency and extend the transmission range of the extinguishing medium. However, the core component, the container valve of the 30Mpa IG541 system, has faced foreign bottlenecks in terms of availability and technology transfer. To address this situation, a domestically developed and independently intellectual property-protected 30Mpa IG541 container valve has been designed and tested. This design encompasses material selection, flow area calculations, action mechanism design, sampling port design, inlet and outlet thread selection, safety diaphragm design, and thread strength calculations. Subsequent testing confirmed its suitability, including functional testing, sealing tests, hydrostatic pressure testing, blast performance testing, and salt spray testing. The valve passed all tests with flying colors, ensuring reliable opening under 135MPa pressure. The container valve has also been successfully certified by DNV. This achievement lays the foundation for the next phase of certification by a classification society and the broader application of this 30Mpa IG541 system in offshore engineering.
Analysis of stiffness characteristics of helical compression springs used in high-precision instruments
Authors: Wang Yu , Zhang Chunguang , Li Shangqing , Li Zhichao , Gong Yingjiao , Liu Jiarui
Published: October 2024

Under working conditions of high-temperature, high-pressure, and strong corrosion, helical compression springs used in high-precision instruments need to maintain linear characteristics and impact resistance. To solve the problem of significantly reduced instrument accuracy due to the stiffness drift of current helical compression springs, compression stiffness characteristics are analyzed through compression tests and finite element simulations. The results indicate that the stiffness drift is caused by the sliding displacement of helical compression springs after being compressed and self-contacted. With the premise of minimizing overall effect on instruments, the helical compression spring structure was redesigned to eliminate the stiffness drift and meet requirements for impact resistance.
Ride comfort analysis on vehicle using a new nonlinear isolator for the seat suspension
Authors: Umair Muhammad , Hou Zhichao
Published: October 2024

Seat suspension plays a crucial role in attenuating low-frequency vibrations and improving overall riding comfort. This paper proposes a new nonlinear isolator for seat suspension using a novel high-static-low-dynamic stiffness with sliding mass inertia (HSLDS-SMI). The HSLDS-SMI seat suspension includes a negative stiffness structure and two secondary sliding masses. A multi-degree-of-freedom (MDOF) dynamic model is developed, comprising a simplified quarter-car model and a biodynamic human model. Various isolation performance indices are then considered and analyzed under two different road excitations using numerical methods. The impact of the sliding mass on ride comfort is examined under both road profiles. The findings demonstrate that the HSLDS-SMI seat suspension performs better than its two counterparts while ensuring the relative suspension deflection remains within acceptable limits.
Rolling Contact Fatigue Life and Categorization of Failure in Experiment of Flat PEEK Race-Alumina Ball Bearings in Water Lubrication under 1700 N at 1000 rpm
Authors: Matsubayashi Soji , Kajiwara Shuhei , Matsueda Takahiro , Kida Katsuyuki
Published: October 2024

The rolling contact fatigue tests of flat polyether-ether-ketone (PEEK) race-alumina balls bearings in water lubrication were done. From the experiments under 1700 N at 1000 rpm, three types of failures were obtained: a crater-shaped flaking, a rhombus-shaped flaking and a large cracking failures. To research the relationships between the failures and the lives, the surface properties near the failures were measured and observed. No relationships between the surface roughness and the life were found. On the other hand, the contact width of the shorter life specimen was larger than that of the longer life specimen. Two types of the flaking holes were compared to study the differences. The crater-shaped flaking hole exceeded the contact track, but the rhombus-shaped flaking hole existed inside the contact track. In addition, the crater-shaped flaking hole was shallower than the rhombus-shaped flaking hole. This means that the flaking mechanisms were different between them, i. e. the differences of the flaking mechanisms caused the differences of the life.
Research status on the effect of energy density on the forming microstructure and properties of nickel-based superalloys for laser additive manufacturing
Authors: Linjie Li , Quanwei Cui , Zhicheng Lu , Haoran Sun , Qiang Li , Wanli Guo
Published: October 2024

Nickel-based superalloys have excellent high-temperature mechanical properties, corrosion resistance and oxidation resistance, and strong machinability. It is widely used in aerospace, submarine and shipbuilding, petrochemical, electronic industry and other industries. However, there are still challenges in the popularization and application of nickel-based superalloys for alloy components with complex structures and extremely harsh working conditions. In this paper, the research status of the influence of energy density on the microstructure and properties of laser additive fabrication of nickel-based superalloys at home and abroad is reviewed. The influence of energy density on the microstructure evolution behavior and mechanical properties improvement effect of laser additive manufacturing nickel-based superalloys is summarized. The mechanism of energy density was discussed from the perspectives of microstructure evolution and macroscopic performance change. Based on the individual effects and synergistic effects of each process parameter, the influence of laser energy density on dendrite growth, phase precipitation characteristics, element distribution and porosity defect control effect of nickel-based superalloy was expounded, as well as the influence mechanism on microhardness, wear resistance and residual stress. Finally, the energy density optimization and development prospect of laser additive fabrication of nickel-based superalloys are prospected.
Development of Test Methods in the Process of Electrically Conductive Concrete Production
Authors: Savytskyi Mykola , Pang Weixiang , Sun Lijun , Savytskyi Oleksandr , Bordun Maryna , Li Yang , Xia Yanfang , Wang Haojie
Published: October 2024

Prevention of climate change, implementation of sustainable development principles in building industry, creation of Green buildings, Three-zero buildings (zero energy, zero emissions, zero waste), energy independent buildings maybe on the base of Smart Concrete. Electrically Conductive Concrete as type of Smart Concrete have the possibilities to create multifunctional hybrid structures for various purposes. The production of electrically conductive concrete is usually based on the introduction of carbon materials and carbon nanomaterials (CNMs) as electrically conductive fillers into its concrete composition. The theory of conductive percolation is used for design of electrically conductive concrete. To select electrically conductive carbon filler, it is necessary to summarize their electrically conductive characteristics. Today, there is no standard for determining the electrical conductivity of carbon fillers, nor is there a method for designing the composition of electrically conductive concrete; the development of both is imperative. Features of the preparation of electrically conductive concrete with hydrophobic carbon nanoparticles prone to aggregation are indicated. To obtain high quality electrically conductive products an operating system for quality control at the stages of the technological process of manufacturing must be proposed. Homogenization of the electrically conductive filler is very important. It is necessary to propose a method for assessing the stability of an aqueous suspension of a hydrophobic carbon material used for homogeneous distribution of a filler. Due to the lack of a standard, a method for determining the electrical conductivity of concrete is also needed.
Texture Evolution of High-purity Tantalum during 90°Clock Rolling
Authors: Zhang Song , Shi Jiaqing , Li Xun , Yu Xiaodong , Tan Chengwen , Nie Zhihua
Published: October 2024

When fabricating high-purity tantalum targets for the sputtering procedure of integrated circuit manufacturing, a through-thickness texture gradient can form in the rolled tantalum (Ta) plate. This texture gradient hinders the target sputtering performance, reducing chip reliability. This study investigated the texture evolution during the 90°clock rolling through experimental and simulation methods. Balancing the plane strain deformation with the surface shear strain deformation during fabrication and limiting the total rolling reduction to no more than 85% can weaken the through-thickness texture gradient in the Ta plate. A crystal plasticity finite element method (CPFEM) model was developed to simulate the 90°clock rolling procedure in the ABAQUS/Explicit software. The simulation and the experimental results are in agreement, with slight differences in texture type and intensity due to tantalum’s complex slip behaviors.
Study on the influence mechanism of austenitizing temperature on the surface of corrosion-resistant mold steel
Authors: Zhao Zhengrong , Zhang Yunfei , Zhao Yingli , Fan Mingqiang , Liu Yong , Mao Yaning
Published: October 2024

The microstructure of 4Cr13 corrosion-resistant plastic mold steel was studied. The martensitic experimental steel obtained by different heat treatment processes was used as the object. The effect of austenitizing temperature on its corrosion behavior was studied by microstructure characterization and electrochemical test. The results show that the microstructure of the test steel is mainly composed of martensite laths. Under the same experimental conditions, the corrosion resistance of the test steel decreases with the increase of austenitizing temperature, and the corrosion products are mainly composed of iron-containing oxides. The austenitizing temperature of 1000°C improves the corrosion resistance of the material, because the precipitation of a large number of small-sized Cr-containing carbides hinders the further erosion of the material and improves the surface quality.
Study of the influence of carbon nanotubes on the superconducting properties of YBCO composite
Authors: Tolendiuly S. , Sovet A. , Fomenko S. , Rakhym N. , Sadykov M. , Asylkhan Sh. , Bolatzhan K.
Published: October 2024

This article describes a method for producing a superconducting composite based on YBCO doped with carbon nanotubes by solid-phase combustion in an atmosphere of pure oxygen. It has been determined that the initial connection of the components, the ignition temperature and holding time, as well as the degree of doping with CNT nanoparticles affect the qualitative and quantitative provision of the superconducting Y123 phase, including its superconducting properties.
Improving performance of GFRP joints using bolted/mortise-tenon hybrid method
Authors: Yue YIN , Haipeng WU , Yunlong SUN
Published: October 2024

In this study, the effects of different connection methods such as adhesives and bolts on the performance of GFRP joints were compared. A hybrid method based on bolted/mortise-tenon was proposed, and the static strength of joints was studied through experiments and numerical simulations. Static trength testing using glass fiber reinforced polyurethane composites. The results showed that for adhesive-bonded joints, double-lap shear specimens have the highest shear strength. For bolted joints, double-lap specimens also have higher connection strength than single-lap specimens. And the strength of joints using bolts is much greater than that using adhesives. In addition, the bolted/mortise-tenon hybrid joint has a self-locking structure of dovetail and tenon connections, which converts shear strength into structural strength, effectively improves the load-bearing capacity, increases the reliability of the connection, and contributes to higher load-bearing capacity.
Corrosion study and microscopic analysis of X65 specimen by sulfate reducing bacteria
Authors: Guanglei Lv , Shining Yuan , Xiaobin Jiang , Yuanyuan Li , Minglei Xia , jie Qu , Donghong Zhao , Jun Chen
Published: October 2024

In this work, the corrosion effects of seawater and production water on X65 specimens with or without bacteria were studied, and weight loss analysis, scanning electron microscopy analysis, EDXA analysis, fluorescence analysis and bacterial content analysis were carried out. The results show that seawater corrosion of X65 is greater than production water. Compared with the sterilized water sample, the SRB in the bacterialized water sample slightly promoted the corrosion of X65, but the promotion effect of SRB on the corrosion of X65 within 7 days was rather limited. The high pressure or high temperature environment is not conducive to the growth and reproduction of SRB, and the remaining small amount of SRB promotes the development of surface pitting of X65 test pieces.
Study on the Stress Intensity Factor of Tilt Crack on the Inner Surface of Pipeline
Authors: Cui Jintai , Li Huifang , Qian Caifu , Wu Zhiwei
Published: October 2024

Cracking is one of the key factors jeopardizing the safe operation of pipelines, and Stress Intensity Factor (SIF) is an important parameter for evaluating the degree of crack danger. Cracks on engineering pipelines often appear in irregular patterns. In this paper, with FRANC3D crack analysis software, SIFs of the circumferential tilt cracks and axial tile cracks on the inner wall surface of a pipe under internal pressure were studied with concentration on the effects of the crack tilt angles. Mode I stress intensity factor weakening effect KI/K0 was defined and influences of the crack tilt angle, pipe and crack size on KI/K0 were investigated. With enough simulation results, empirical formulas for calculating the Mode I SIF for the circumferential or axial tilt crack were obtained by modifying the formulas for calculating the SIF of the crack in AMSE FFS-1.
Analysis of Combustion Characteristics of Can-Type and Annular-Type Combustion Chamber
Authors: Smitha D. , Satyanarayana M. R. S. , Srivastava Sachin
Published: October 2024

High performance is always desired for the propulsion system and the assortment of a better combustion type is also a vital part of the propulsion system. The analysis of different designs of combustion chambers and comparison of their combustion characteristics. In this paper, the assessment of Can-type and Annular-type combustion chambers and the design developed with SOLIDWORKS software and analysis done with ANSYS FLUENT. The systematic and translucent method approaches reduce the design complexity and time. The combustion with turbulence interface was examined to analyze with precision results, and the analysis specified that the nowadays experiment depends on the behavior of gas exit pressure, temperature, and velocity. Parametric analysis is used to acquire the sizing of the combustion chamber.
Deformation and enclosed volume change of axisymmetric non-linear dielectric elastomer membrane pump: a theoretical study
Authors: Kumar Nirmal , Sriharsha S.O.V. Jaswanth , Bollu Rakesh , Reddy Vancha Bhaavan
Published: October 2024

This work investigates the change in the enclosed volume of an axisymmetric non-linear hyper-elastic membrane pump subjected to dielectric actuation. The equilibrium equations in cylindrical coordinates, coupled with non-linear constitutive relations, are solved numerically to obtain the deformed membrane geometry under pressure loading (using Variational Calculus). The effect of dielectric actuation is then incorporated by considering the change in material properties and deformation induced by the applied electric field. The deformed geometry under dielectric actuation is determined, and the change in enclosed volume is calculated by comparing the deformed states with and without the applied electric field. The proposed approach enables quantifying the volumetric change in non-linear hyper-elastic membrane pumps due to dielectric actuation for potential applications in soft robotics, adaptive optics, and microfluidics. By non-dimensionalizing variables, key dimensionless parameters governing the problem are identified for broader applicability. Furthermore, this methodology can estimate volume changes for different electric actuations when a specific material is chosen with experimentally derived parameter trends, facilitating material selection or synthesis to meet targeted volumetric requirements.
An investigation of prototype development using 3D printer: A digital fabrication approach
Authors: Rana Amit Kumar , Kundu Sanjib , Datta Suchibrata
Published: October 2024

Additive manufacturing (AM) is a widely used technique in several industries for rapid prototyping and layer-by-layer fabrication of a new product. The influence of printer settings and print quality is essential for the performance of products in a variety of applications. The popularity of manufacturing using 3D printing is growing rapidly. In view of this, an investigation is carried out on the 3D printing techniques, their applications, and prototype materials for complex mechanical parts such as an impeller. The present study thoroughly considers the fundamental techniques in 3D printing technology, materials, and recent advancements applied to the current application and accepted trends. The 3D printing technology is advantageous as it accepts a wide range of designs, allows customized manufacturing, minimizes waste, builds intricate structures, and creates prototypes rapidly. Layer height of 0.2 mm, speed of 90 mm/s, and infill density of 80% were determined as the optimal print settings considering time, material cost, and properties. Considering the flexural qualities, the optimized values of layer height, print speed, and infill density were 0.15 mm, 70 mm/s, and 50%, respectively. It was observed that the uniform elongation (UEL) and ultimate stress (UTS) of a component increase as the layer thickness increases for the considered layers.
A Review on Cushioning Characteristics in High-Speed Hydraulic Actuators
Authors: Kanaskar A S , Sapali S.N. , Haribhakta V.K. , Sati SC
Published: October 2024

High speed actuators are an integral part of the fluid power driven systems and cylinder cushioning requirement in these actuators is one of the important aspects. Cushioning is imperative in any high-speed actuator as it not only increases its life but also gives operating comfort to the operator. Fluid power driven systems are very common in many defence and industrial applications due to their high force/torque and power density. This review paper brings out the available literature in the field of hydraulic cylinder cushioning. Literature, consisting mainly of journal articles, research papers and other media contents is analysed for the key parameters of research in this field. The classification of cushioning methodology by different researchers is projected. The methodologies of modelling and simulation work carried out by various authors are analysed. Thereafter the optimization studies done for the cushion piston design in various literature are discussed. Lastly, experimental validation strategies as employed in certain papers are also brought out. Experimental study, and validation of non-conventional cushioning methodology is discussed, which is not much evidenced in the literature.
Properties and Characterization of Nanocellulose
Authors: Mishra Upasana , Neeraj
Published: October 2024

In the field of nanotechnology, nanocellulose plays crucial role. Some features of nanocellulose like high surface area, crystallinity, porosity and tensile stress makes remarkable changes in medical and Industrial area. It is known for its biocompatibility, renewability, high aspect ratio, infinitesimal toxicity and sustainability. Nanocellulose can be prepared by microcrystalline cellulose. For the synthesis of nanocellulose, Acid hydrolysis procedure was used. Various methods of characterizations were used for the prepared nanocellulose such as “Fourier transforms infrared spectroscopy (FT-IR), Scanning Electron Microscopy (SEM) and X-ray diffraction”. Nanocellulose drew the attention of scientists for their biochemical properties due to its physical and chemical structure. Various applications of nanocellulose in different field such as biochemical, waste water management, electronics, packaging, automotive etc.
Optical parameters of PANI.CSA/PMMA nanofibers
Authors: Fadhil Wasan Adeeb , Essa Hanaa K , Rasheed Hiba S , Alwan Tariq J
Published: October 2024

Polyaniline doped with camphor sulphonic/Poly(methyl methacrylate) PANI.CSA/PMMA nanofibers were manufactured by electrospinning technology, where all parameters of the electrospinning system are fixed and the effect of the needle gauge on the properties of the prepared nanofibers is studied at different needle gauge (18, 20, 23 G). The polyaniline was manufactured by aniline-chemical oxidation polymerization. The nanofibers were diagnosed by an FE-SEM scanner to identify the surface morphology of the samples and the diameters of the nanofibers, it shows that nanofibers become more regular and their diameters become smaller as the diameter of the needle decreases. The samples were measured by the analysis of UV-visible spectroscopy, identifying the optical properties of the nanofibers and calculating the energy gap, which was valued ranging from 2.8 eV to 3.2 eV, increased due to the phenomenon of the quantitative restriction. Absorption coefficient and optical constants were also studied as a function of needle gauge.
Manufacture and study the mechanical, thermal and physical properties of plastic wood
Authors: Fadhil Rihab Nassr , Jasim Muna B. , Abdullah Zainab Assif , Mahdi Shatha H. , Jasim Kareem A.
Published: October 2024

This study focuses on evaluating the mechanical properties and thermal conductivity of unsaturated polyester (UPE) composites reinforced with Pistacia shells (Pi-S). Wood-plastic composites were prepared using UPE reinforced with Pi-S at different weight ratios (50%, 60%, 70%). The main objective of this work is to recycle Pistacia shells in significant proportions and assess the impact of using Pi-S as reinforcing materials in UPE. Mechanical tests, such as Shore D hardness, impact resistance, and compressive strength, were employed to evaluate the mechanical properties of the composites. The results showed that the 50% weight ratio achieved the highest values in all tests compared to other ratios (60%, 70%). Impact resistance increased to 10.15 Kj/m2 at the 50% weight ratio, followed by the 60% weight ratio with the highest impact resistance. The results also indicated a slight decrease in Shore D hardness with an increase in the weight ratio and a decrease in compressive strength. Regarding thermal conductivity, the highest thermal conductivity value was at the 50% weight ratio, with a value of 0.68118762 W/mk. It then decreased at the other weight ratios but remained higher than the thermal conductivity of pure unsaturated polyester. This technique allows for the full utilization of Pistacia shells in the wood-plastic industry, contributing to various applications such as wooden and plastic flooring, surfaces, doors, and more.