bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural and phase transformations in Fe-Pd-Ag layered thin films by grain boundary diffusion
Authors: Gulyás Szilvia , Katona Gábor L
Published: August 2024

The influence of the stacking order and of an additional Ag layer on the formation of ordered phases in thin (< 50 nm) layered Fe/Pd and Fe/Ag/Pd films was investigated at 460 °C. The samples were prepared by magnetron sputtering at room temperature on Si/SiO2 substrate and were post-annealed in vacuum. Composition depth profiling and x-ray diffraction were used to characterize the processes. It has been shown, that the stacking order strongly influences the formation of ordered phases both in Fe/Pd bilayered and Fe/Ag/Pd trilayered films. In bilayered Fe/Pd films for both stacking orders the FePd3 phase appeared and it also showed L12 ordering for one stacking order. Addition of Ag layer between the Fe and Pd layers found to promote the formation of FePd phase which showed L10 ordering or A1 disordered structure depending on stacking order. Based on the analysis of the chemical depth profiles and XRD patterns the transformations were interpreted by grainboundary diffusion mechanisms including grainboundary diffusion induced grainboundary migration and solid state reaction.
Early and late observational tension: dark energy parametrizations in horava-lifshitz gravity via baryon acoustic oscillations
Authors: Chaudhary Himanshu , Debnath Ujjal , Rahaman Farook , Mustafa G , Atamurotov Farruh
Published: August 2024

We investigate late-time cosmic expansion within the Horava Lifshitz gravity framework using Barboza Alcaniz (BA) and Jassal Bagla Padmanabhan Parametrizations (JBP) as alternatives to general relativity. Anisotropic scaling is introduced at ultraviolet scales. Our aim is to constrain each cosmological parameter using the crucial Baryon Acoustic Oscillation (BAO) scale, specifically the sound horizon (r

d
), by treating (r

d
) as a free parameter. We employ 30 Hubble parameter measurements (H(z)) from cosmic chronometers, along with Type Ia Supernovae, Gamma-Ray Bursts, Quasars, and 24 uncorrelated BAO measurements spanning z = 0.106 to z = 2.33. The analysis includes the 2022 Hubble constant measurement by Riess (R22) as an additional prior and aims to minimize errors by simulating random correlations in the covariance matrix. In both the BA and JBP frameworks, utilizing the full dataset yields sound horizon results of r

d
= 146.5399 ± 2.4519 Mpc and r

d
= 146.4533 ± 2.4519 Mpc, respectively. When incorporating R22 results, the sound horizon values become r

d
= 143.4721 ± 1.8324 Mpc and r

d
= 142.9826 ± 1.9084 Mpc. These findings reveal a discrepancy between early and late observations, echoing the H
0 tension. Notably, excluding R22 aligns r

d
with Planck and SDSS results. Model predictions are evaluated against Hubble Measurements and the ΛCDM Paradigm. A comparative study between BA and JBP Models using the Cosmography test shows both models fitting seamlessly within the phantom region. Statistical analysis suggests neither model can be ruled out based on the latest observational measurements.
Structural evolution of zinc doped cadmium telluride at high pressure and high temperature
Authors: Aparajita A N Arpita , Shukla Balmukund , Vijayakumar P , Kumar N R Sanjay , Ganesamoorthy S , Srihari V , Shekar N V Chandra
Published: August 2024

Cd0.9Zn0.1Te (CZT) has gained a lot of traction with its application in the field of radiation detectors. In this study, CZT has been investigated using in situ x-ray diffraction(XRD) at high pressures up to 22 GPa, and both high pressure and high temperature (HP HT) up to 5 GPa and 400 °C. CZT adopts zinc blende phase at ambient condition. We have observed the previously unreported cinnabar type phase in CZT at high pressure. Cinnabar type phase nucleated at 1.8 GPa because of the motion of Te atoms in the ab-plane of zinc blende CZT and coexisted with the parent phase. The onset of transition to rocksalt phase took place at 4.7 GPa with successive atomic displacement along a and c direction of the cinnabar type unit cell. The parent phase disappeared at 6.3 GPa, but cinnabar type phase as a distorted form of rocksalt phase coexisted with the rocksalt phase due to the comparable energy for both the structures. The mechanism of transitions to cinnabar type and rocksalt phase is of quasi-reconstructive nature. Further, the rocksalt phase underwent a displacive transition to an orthorhombic (Cmcm) phase at 10.7 GPa which is accompanied by expansion along one axis and compression along the other two axes. In the reverse pressure cycle, the transitions were reversible and sluggish in nature. In the in situ high pressure and high temperature XRD studies, distinct structural hysteresis was observed and the transition to rocksalt phase was irreversible. At ambient pressure, the zinc blende structure remained stable up to 400 °C. The thermal expansion coefficient of the zinc blende phase and the high pressure rocksalt phase were estimated to be 23(1) × 10−6/°C and 10.2(1) × 10−6/°C respectively.
Reconsideration of Wigner’s Supermultiplet Symmetry
Authors: Draayer Jerry P , Pan Feng , Dang Phong
Published: August 2024

The objective of this ‘Reconsideration of Wigner’s Supermultiplet Symmetry’, which Wigner advanced in 1937, and for which he was awarded the Nobel Prize in Nuclear Physics in 1963, is first to take a cursory look back at physics-related issues and competing priorities of that (WW-I & WW-II) dominated period, since in retrospect it seems Wigner’s Supermultiplet Symmetry (respectfully denoted WSS in all that follows) is an example of a theory that seems to have been proffered ‘ahead of its time’. Secondly, to reflect on what has transpired over the follow-on decades of the Cold-War Era (1950s through 1980s); specifically, regarding the role that the WSS played (or did not play) across that period. And thirdly, to review the transformational changes of the late 1980s into the 1990s, and thereafter that came with the availability of high-performance supercomputing facilities and advanced algorithmic developments that opened new doors for the testing of more sophisticated models of nuclear structure which ultimately, at the onset of the 21st Century, led to the development of what was christened the ‘no-core’ shell-model (NCSM) by its developers. Shortly afterward, this was followed by the release of a symmetry-adapted version (SA-NCSM) of the NCSM, both of which have been advanced further over the ensuing years for carrying out ever more realistic, forefrontab initioshell-model calculations. Most recently, based upon the lessons learned through the creation, deployment, and updating of the SA-NCSM, it seems it should now be possible to address any and all of the remaining issues that stand in the way of establishing a truly 21st Century Shell-Model Theory that meets most, and perhaps even all, of the expectations that Wigner seemed to envision in his 1937 proffering of the WSS concept.
Impact of segregation and integration on infection dynamics: analysis of a Cholera model in a two-population system
Authors: El Deeb Omar , Matar Antoine
Published: August 2024

We present a novel dynamic model designed to depict Cholera outbreaks within a two-population framework featuring two environmental reservoirs. The model is designed to emulate the impact of segregation or integration between two populations on the transmission of the disease and infections throughout the entire community, both with and without non-medicinal interventions. This is achieved by allowing infectious individuals to interact with the reservoir of the alternate population at different levels of suppression, in addition to their regular interaction with their own reservoir. We find out that increased suppression of cross community interaction reduces the number of infections in the overall population as well as in the population with less contamination and contact. Additionally, we predict significant delays in the occurrence of peak infections, affording public health authorities crucial time for intervention. Lowering cross-immunity interactions also leads to a decrease in bacterial concentrations in environmental reservoirs. Finally, we demonstrate that non-medicinal interventions, including sanitation and water purification, would significantly reduce and delay infections, providing a valuable time frame for implementing additional medicinal measures.
Phase-resolving the Absorption Signatures of Water and Carbon Monoxide in the Atmosphere of the Ultra-hot Jupiter WASP-121b with GEMINI-S/IGRINS
Authors: Wardenier Joost P. , Parmentier Vivien , Line Michael R. , Weiner Mansfield Megan , Tan Xianyu , Tsai Shang-Min , Bean Jacob L. , Birkby Jayne L. , Brogi Matteo , Désert Jean-Michel , Gandhi Siddharth , Lee Elspeth K. H. , Levens Colette I. , Pino Lorenzo , Smith Peter C. B.
Published: August 2024

Ultra-hot Jupiters (UHJs) are among the best targets for atmospheric characterization at high spectral resolution. Resolving their transmission spectra as a function of orbital phase offers a unique window into the 3D nature of these objects. In this work, we present three transits of the UHJ WASP-121b observed with Gemini-S/IGRINS. For the first time, we measure the phase-dependent absorption signals of CO and H2O in the atmosphere of an exoplanet, and we find that they are different. While the blueshift of CO increases during the transit, the absorption lines of H2O become less blueshifted with phase, and even show a redshift in the second half of the transit. These measurements reveal the distinct spatial distributions of both molecules across the atmospheres of UHJs. Also, we find that the H2O signal is absent in the first quarter of the transit, potentially hinting at cloud formation on the evening terminator of WASP-121b. To further interpret the absorption trails of CO and H2O, as well as the Doppler shifts of Fe previously measured with VLT/ESPRESSO, we compare the data to simulated transits of WASP-121b. To this end, we post-process the outputs of the global circulation models with a 3D Monte-Carlo radiative transfer code. Our analysis shows that the atmosphere of WASP-121b is subject to atmospheric drag, as previously suggested by small hotspot offsets inferred from phase-curve observations. Our study highlights the importance of phase-resolved spectroscopy in unravelling the complex atmospheric structure of UHJs and sets the stage for further investigations into their chemistry and dynamics.
Authenticated multi-party quantum key agreement protocol based on cluster states
Authors: Zhang Li , Han Zhaowei , Li Yuehua , Ma Qiuyu , Li Lele
Published: August 2024

Quantum key agreement (QKA) is an important cryptographic primitive that plays a pivotal role in private communications. Authenticated QKA plays an important role in QKA. In this paper, we propose an authenticated multiparty QKA scheme based on 4-qubit cluster states entanglement swapping. The scheme is divided into two parts, the first part is the quantum identity authentication stage, and the second part is the QKA stage. In the quantum identity authentication stage, the participants determine that the participant communicating with them is the claimed person through mutual authentication, which can avoid the impersonation attack of the eavesdropper Eve. In the QKA phase, the participants adopt a bidirectional transmission structure with the participation of a semi-trusted third party, and based on the entanglement swapping property of the 4-qubit cluster state, the QKA is finally realized. Detailed security analysis shows that the protocol can resist a variety of internal and external attacks, such as participants attack, entangle-measure attack, and so on.
Resistive wall tearing mode disruptions
Authors: Strauss H.R. , Chapman B.E. , Lyons B.C.
Published: August 2024

This paper deals with resistive wall tearing mode (RWTM) disruptions. RWTMs are closely related to resistive wall modes. RWTMs are tearing modes whose linear and nonlinear behavior is strongly dependent on the resistive wall outside the plasma. The consequence for ITER, is that the thermal quench timescale could be much longer than previously conjectured. Active feedback stabilization is another possible way to mitigate or prevent RWTM disruptions. Simulations of RWTM disruptions are reviewed for DIII-D and MST. MST has a longer resistive wall time than ITER, and disruptions are not observed experimentally when MST is operated as a standard tokamak. Simulations indicate that the RWTM disruption time scale is longer than the experimental shot time. Edge cooling causes contraction of the current profile, which can destabilize RWTMs. The equilibria studied here have the q = 2 rational surface close to the edge of the plasma, and low current density between the q = 2 surface and the wall. A sequence of low edge current model equilibria has major disruptions only for a resistive, not ideal, wall, and edge

q
⩽
3.4
.

This is consistent with regimes of tokamak disruptivity, suggesting that tokamak disruptions caused by edge cooling at low edge q could be RWTMs.
Research on virtual flight test method for minimum unstick speed of civil aircraft
Authors: Zhang Zhifei
Published: August 2024

The physical process analysis of minimum unstick speed flight test of civilian aircraft is carried out. A simulation environment is built for the virtual flight test based on Simulink and MATLAB script. The pilot control behavior is modeled, and the model control algorithm is given to realize the automation of the simulation process. By comparing with the flight test data, the feasibility of the virtual flight test method is demonstrated, and the improvement direction of the pilot control behavior model is given.
Damage analysis of HTPB propellant based on temperature load test
Authors: Li Jinfei , Zhuang Zhenmin , Qu Kai , Zhang Liping
Published: August 2024

In this paper, the HTPB propellant of a solid rocket motor was taken as the research object. Considering the effect of temperature on the propellant, various types of tests were carried out to study the damage law of the propellant at the macroscopic scale. The aging of HTPB propellant under temperature loading is mainly manifested as oxidative cross-linking of the binder network. The greater the cross-linking degree of the specimen is, the smaller the maximum elongation of the propellant is. Under constant strain load, some AP particles will be dehumidified, and at room temperature, AP particles will decompose slowly, resulting in an increase in strength and a decrease in elongation. The aging of HTPB propellant under constant strain loading at high temperatures is manifested as oxidation cross-linking of the binder network, εm
of propellant declines, and σm
of propellant is reduced.
Research on the flow field characteristics of solid rocket motor work at high altitudes based on immersed boundary method
Authors: Song Daquan , Wang Jian , Lin Qingyu
Published: August 2024

Due to the difficulty of using the body-fitted mesh method to deal with complex moving boundaries, this article proposes to use the immersed boundary method to handle the combustion surface regression generated by the propellant combustion. The effectiveness of the immersed boundary method is verified through simulation calculations of the working process of the rocket engines working at high altitudes, and the flow field characteristics are analysed. The research finds that the higher the flight altitude is, the larger the initial expansion angle of the gas jet, the radial boundary of the jet flow-field, and the length of the jet starting section are. The larger the flight Mach number is, the smaller the initial expansion angle, radial boundary, and length of the starting section of the gas jet are. However, the length of the jet transition section has increased, and the fully developed section of the jet has moved back.
Fast non-singular terminal sliding mode control of the cubesat attitude for on-orbit assembly process
Authors: Yan Mingzheng , Song Xiaodong , Shi Jixin , Zhao Bo , Zhang Haosen
Published: August 2024

The construction of space assemblies using on-orbit assembly technology is beneficial for supporting various complex space missions, and has broad application prospects and high practical significance. This paper designs a novel terminal sliding mode attitude controller to address the time-varying mass parameters and suppress internal and external disturbances during the on-orbit assembly process of CubeSat. Specifically, the CubeSat attitude dynamics model with a telescopic mechanism is established based on the vector mechanics method. Subsequently, given the expressions for fast, non-singular terminal sliding surfaces and adaptive power-reaching laws, the controller’s stability is demonstrated. Then, the variation pattern of the model parameters is determined through dynamic simulations, and finally, extensive simulations verify the attitude control effect of the two CubeSats in the on-orbit assembly process. The simulation results demonstrate that the proposed method is robust to time-varying and jumping CubeSat mass parameters and presents a significant suppression effect on random interference caused by the shaking of the telescopic mechanism and the impact torque at the moment of the docking lock. The proposed method has faster attitude convergence and smoother control torque than traditional sliding mode control methods.
MGCNet: Low-cost MEMS gyro correction network
Authors: Yin Yunsheng , Xu Linhai
Published: August 2024

MEMS gyro is widely used in the field of autonomous system navigation, but due to the large measurement error of low-cost MEMS gyro, the orientation estimation of gyro carriers cannot be met by simple calibration only. In this paper, we propose a learning method to correct the measurement error of MEMS gyro in IMU. Our method utilizes dilated convolution to increase the receptive field, designs a lightweight attention module to extract the gyro random error, and uses channel transformation to extract deterministic errors. We also design a multi-timescale loss function, enabling the network to notice the cumulative orientation errors at different timescales. We tested our method on public datasets EUROC and TUM-VI and compared it with the Visual-Inertial Odometry (VIO) methods as well as other gyro correction methods. The experimental results show that the proposed method can have comparable or even higher accuracy of orientation estimation than the visual inertial combination method, and the gyro orientation estimation error using MGCNet correction is reduced by 15-20% compared to other advanced gyro processing methods.
Design approach of contingency point return trajectory for manned lunar missions based on homotopy continuation
Authors: Lu Lin , Li Haiyang , Dong Tianshan , Zhu Binyu
Published: August 2024

In terms of the requirement of contingency return during the circumlunar flight phase in manned lunar missions, this article presents a contingency point return trajectory design approach. In consideration of the point return constraint, an initial value estimate model is proposed. A nonlinear programming problem is constructed and solved by adopting an improved differential evolution algorithm with good global search ability. On the basis of the initial value estimate, homotopy continuation is used to gradually approximate and obtain the high-fidelity solution. The simulation results indicate that the design approach can effectively calculate a contingency point return trajectory with good convergence.
Optimal design of uniform magnetic field coils within irregular magnetic shielding based on coupled SNOPT-finite element method analysis
Authors: Jie Shaofeng , Liu Zhanchao , Zhang Shuai , Wang Jingsong , Wu Zekun , Zhao Kangnan
Published: August 2024

The highly uniform magnetic field coil is one of the most important components of miniaturized atomic inertial sensors. However, the development of the magnetic field model of coils in magnetic shielding with irregular shapes is difficult in practice. In this study, an optimization method for the design of coil structure parameters based on hybrid modelling with the finite element method and the SNOPT algorithm was proposed. The finite element method was used to characterize the geometric structure of the magnetic shield accurately and incorporate the characteristic B-H parameters of the material into the optimization model to improve the design accuracy. The three-dimensional model was reduced to two dimensions, and the parameters of the coil structure were optimized by an intelligent algorithm, which improved the solution efficiency. The effectiveness of the proposed approach was demonstrated by optimizing the design of a solenoid coil inside the cylindrical magnetic shielding with holes and stovepipes, which reduced the design error caused by the magnetic leakage flux.
Modal classification and identification of hypersonic inlet
Authors: Yang Kongqiang , Fan Xiaoqiang , Xiong Bing , Tang Xiao , Mou Wanhui
Published: August 2024

Based on previous research, as flight parameters change, the inlet will undergo four operating modes, among which the non-starting mode significantly degrades the quality of the inhaled airflow, thereby affecting engine performance. To identify the operating modes, this paper proposes an analysis method based on the ISOMAP dimensionality reduction model. First, preprocess the wall pressure data, and ISOMAP is used to extract features and reduce dimensionality. Then, the corresponding relationship between characteristic points and modes is established manually, and the pressure distribution is labeled and compared with the known sequence. The result shows that the established dimensionality reduction model can effectively identify the inlet operating modes, reveal four types of flow field characteristics, and provide a new method for rapid identification of inlet operating modes.
Dynamic simulation analysis and experimental verification of a typical aircraft structure
Authors: Fu Yue , Li Kun , Ren Jiannan , Zhao Cheng
Published: August 2024

Finite element software was adopted to conduct the vibration modal analysis and frequency analysis of a typical aircraft structure, and modal verification tests were conducted on the typical aircraft structure. Based on the indicator functions, the effectiveness of experimental results was evaluated and the pure modal results as evaluation criteria for simulation analysis results were selected. Among the eight results, the simulation analysis results of six modes are in good agreement with the experimental results, while the two modes of the simulation analysis results are consistent with the experimental results.
Optimization method based on approximate gradient analysis and its application in aerodynamic design
Authors: Liu Miao , Qian Ruizhan , Wei Jianlong , Lei Wutao
Published: August 2024

An efficient optimization method based on approximate gradient analysis was proposed to reduce the substantial computational burden in expensive optimization problems, in which the objective functions are evaluated with high-fidelity analyses in one-dimensional linear search, while the gradients are evaluated with an approximation model during the optimization process. Taking advantage of the similarity of CFD models with different fidelities, we employ a less time-consuming low-fidelity model as its main section, and use the gradient information of the high-fidelity model at the initial point as an amendment. The proposed procedure was applied to the aerodynamic optimization of a well-designed supercritical wing, resulting in obvious drag reduction, but the CPU time is only 28.5% as its SQP counterpart. The investigation indicates the proposed method is suitable for aerodynamic improvement of an existing baseline configuration to meet specified engineering requirements.
Equivalent simulation test method of engine plume thermal environment in aerobic environment
Authors: Pan Shangjie , An Wanqing , Liu Zhe , Xia Chaoran , Meng Ran , Jin Chenwei
Published: August 2024

The deep space probe is generally composed of the lander and the lander. During the take-off and landing of the extraterrestrial body, the engine jet flows through the top surface of the lander or the surface of the extraterrestrial body to reflect on the bottom surface of the lander, which will produce strong aerodynamic and thermal effects in a small space, thus affecting the stability and surface thermal protection of the lander. The plume heat effect refers to the impact of the flyover engine gas flow movement or heat radiation on the lander surface on the flyover bottom, tank, lander top surface, buffer mechanism, and key equipment. This paper calculates from the probe plume thermal environment equivalent simulation method, and heat flow simulation loading system design until the test verifies that the affected product surface temperature rises. It can provide necessary technical support for the selection of thermal control protection materials (conventional thermal control, flexible thermal protection materials, high-temperature thermal protection materials).
Numerical study on the interaction between turbulent grazing flow excitation and Helmholtz cavity
Authors: Li Xingda , Yu Zhefeng , Dang Huixue
Published: August 2024

In response to the problem of abnormal noise in typical aircraft structures with gaps and cavities, an experiment on a Helmholtz cavity excited by turbulent grazing flow was designed. The computational fluid dynamics software FLUENT was used to simulate the flow-induced noise of the Helmholtz cavity based on the Large Eddy Simulation (LES) method. By comparing with experimental data, the numerical simulation was validated. Meanwhile, under the given orifice size, the Helmholtz resonance effect of the cavity was studied at different velocities. It is found that the fluid oscillation frequency of the cavity orifice increases with the velocity under the given orifice size. When the fluid oscillation frequency at the cavity opening approaches the Helmholtz resonance frequency of the cavity, Helmholtz resonance occurs, leading to a significant increase in sound pressure level. Moreover, within a certain velocity range, the lock-in phenomenon occurs, and the lock-in frequency increases with the increase of inflow velocity, resulting in a frequency shift phenomenon. As the velocity increases, the lock-in phenomenon will break. This study suggests that Helmholtz coupling resonance and sound caused by the oscillatory flow with a close frequency to the cavity are one of the main causes of abnormal noise during aircraft flight.
Dynamic SLAM diagnosis method for uncontrolled fault of aircraft electronic anti slip braking system
Authors: Ma Haiguo , Ma Wenqian
Published: August 2024

In order to accurately diagnose the out-of-control fault of an aircraft’s electronic anti-skid braking system, a dynamic SLAM diagnosis method for the out-of-control fault of an aircraft electronic anti-skid braking system is proposed. Using an optical module, image acquisition module, power module, main control module, etc., the dynamic drawing image of aircraft taxiing is acquired. By establishing a dynamic map of aircraft taxiing, the dynamic semantic mapping results are obtained. The out-of-control fault diagnosis model of the depth residual network is constructed, and the aircraft taxiing semantic data is used as input data to output the out-of-control fault diagnosis results. The experimental results show that with the increase of Gaussian white noise intensity, the deviation factor of out-of-control fault diagnosis in the design method increases less, and the sample label misjudges less in the noise-free environment.
Synthetic reliability assessment for non-electric stimulus transfer system
Authors: Ma Xiaodong , Sun Liang , Gu Changchao , Gao Fei , Hong Dongpao
Published: August 2024

The Non-electric stimulus transfer system (NSTS) is a sensitivity product known for its high reliability. To enhance the accuracy of reliability assessment for NSTS, this study investigates the relationship between NSTS and initiating devices, and proposes a synthetic reliability assessment method. By considering the working principle and failure logic of typical NSTS, function-shared units are introduced to enhance the reliability model of NSTS. Subsequently, the reliability of NSTS is approximated by using the normal distribution, incorporating the reliability evaluation of initiating devices and the test data of NSTS to derive an approximated confidence interval. The analysis of a practical case demonstrates that this synthetic reliability assessment method is well-suited for engineering applications.
Study on aerodynamic noise of condensing fan of new energy vehicle air conditioner
Authors: Tong Guang , Li Sijie , Yang Haijun
Published: August 2024

With the growth of low-carbon environmental awareness, more and more new energy vehicles appear in the market. This paper focuses on the issue of noise caused by the condensing fan in new energy vehicles. The noise is generated due to the airflow in the blade gap. Starting from the fan structure, the paper proposes a serrated structure on the surface of the fan blade to improve the fluid vortex gas flow at the tip of the blade. The orthogonal test method sets the number of serrations, length, and cutting depth as three-level factors, and the noise at the monitoring point of the condensing fan is used as the evaluation index of aerodynamic performance. The results show that the noise of the condensing fan is significantly improved.
Wear and corrosion-resistant Al2FeCrMnTix laser cladding coatings - From powder production by high temperature remelting spheroidization to coating built-up by Laser Powder Bed Fusion
Authors: Liu Jie , Guo Yongqiang , Du Kang , Wang Wei , Fan Chenjie , Zhang Wenqi , He Jiayu , Guo Hongmin , Gu Zhen
Published: August 2024

High entropy alloys (HEAs) have unique mechanical and electrochemical properties in various of fields. Laser powder bed fusion (LPBF) is a prominent additive manufacturing process. It uses thermal energy to bind powder materials together to build plastic or metal parts. The technology has a remarkable effect on improving the corrosion resistance and wear resistance of the agitating blade coatings. However, the traditional gas atomization method (GA) often produce alloy powder (containing refractory element, such as Nb, W) with uneven composition, affecting the quality and performance of specimens. That is why innovative or opposite classical production powder methods are in demand for LPBF. It is worth noting the mechanical alloying - high temperature remelting spheroidization dual process (DP) method could overcome the limitation of high temperature alloying of HEA containing refractory elements and realizes solid alloying of insoluble elements. In this paper, high entropy alloy Al2FeCrMnTix (x=0.25,0.5,0.75,1) is designed by means of composition control. The experimental results show that Al2FeCrMnTix is a single phase solid solution BCC structure. With the increase of Ti content, the corrosion resistance of Al2FeCrMnTix HEA coatings were enhanced at a certain range in simulated saturated brine solution. When Ti=0.75, the self-corrosion voltage is -0.179V and the self-corrosion current is 5.764×10−6 mA·cm−2. All coatings offer better corrosion resistance than 316L stainless steel substrates. Particularly, the Al2FeCrMnTix HEA coating can greatly improve the microhardness and wear resistance of the material surface. The average microhardness value of HEA coating reaches up to the maximum (726 HV0.2) when Ti=1, which is about 3.6 times that of the base matrix (316L). These findings have clear implications for coatings used to protect surfaces. Overall, It is clear that Ti0.75 represents lower volume wear rates and smoother wear surfaces, demonstrating better corrosion and wear resistance compared to other coatings.
Impact of Impurity Ions in Secondary Circuit Water on Cracking Behaviour of PWR Steam Generator 690TT Tube
Authors: Song Lijun , Tian Zhaohui , Xu Xinhe , Cui Tongming , Lu Zhanpeng , Qiao Hang
Published: August 2024

The impact of impurity ions on stress corrosion cracking (SCC) sensitivity of steam generator heat-exchange tube material Alloy 690TT in secondary circuit water (SCW) was studied at 285 °C. The pH of the test solution was adjusted using ammonia to be about 9.7. The dissolved oxygen concentration is less than 1 μg/kg, and the ammonia concentration is 50 to 100 μg/L. A slow strain rate test (SSRT) was employed to evaluate the SCC sensitivity in SCW with various types and concentrations of impurity ions. After the SSRT test, the fracture surfaces of the specimen were observed and analyzed using scanning electron microscope (SEM). In SCW environments containing 3 g/L Cl− or 5 g/L SO4
2−, local intergranular cracks were found at the fracture surface edges of the specimens, indicating a certain sensitivity to SCC. When the concentration of SO4
2− was reduced to 5 mg/L, the intergranular crack characteristics of the Alloy 690TT became less apparent, suggesting a high resistance to SCC under low SO42− concentrations.
Study on atmospheric corrosion characteristics and coating protection of urban water supply pipeline
Authors: Li Tao , Zhu Zhiping , Zhou ShangMing , Yang Huo
Published: August 2024

Most of the water supply pipes in the city have corrosion problems during long-term use. To comprehensively understand the corrosion law of water supply pipelines and put forward scientific and effective countermeasures, firstly, the two commonly used materials of ductile iron and Q235 water supply pipelines were subjected to outdoor exposure experiments for one year, and the corrosion kinetic process was analyzed using XRD, EDS, and electrochemical testing, and the atmospheric corrosion mechanism was analyzed; based on this, four kinds of heavy duty anti-corrosion coatings of polyurethane, fluorocarbon, cold galvanizing, and chlorinated rubber were used to coat the specimens of water supply pipelines. On this basis, four kinds of heavy-duty anti-corrosion coatings, polyurethane, fluorocarbon, cold galvanizing, chlorinated rubber, anti-corrosion coating of water supply pipe specimens, examined the four types of coatings of acid, alkali, salt resistance, electrochemical methods to assess their corrosion resistance characteristics, a comprehensive assessment of their application potential, the results show that chlorinated rubber heavy-duty anti-corrosion coating is more suitable for ductile iron pipes, fluorocarbon heavy-duty anti-corrosion coating is more ideal for Q235 pipeline. This study provides data reference for the coating method of corrosion protection for water supply pipelines.
Analysis of corrosion failure causes of hongjing line crude oil pipeline
Authors: Peng Yunchao , Chen Huang , Wen Mengnan , Yan Tong , Fu Yu , Sun Shuangqing , Hu Songqing
Published: August 2024

Pipeline corrosion occurred somewhere in the Hongjing Line crude oil transmission pipeline. In order to investigate the cause of pitting perforation, the corrosion perforation of pipeline was analyzed by optical microscope, scanning electron microscope, fluorescence quantitative PCR and X-ray diffraction analysis, combined with the corrosion simulation experiment of weightloss method. Results On the surface, the pipeline material (L360) met the requirements of API5L standard, and the corrosion form was perforation caused by pitting on the inner wall. The main corrosion products are Fe2O3, FeCO3 and FeS. It is found that the concentration of Cl− in the sedimentary water is as high as 30363.8 ppm, which indicates that the main reason for the corrosion of the crude oil pipeline is the pitting corrosion caused by Cl−.
Research progress and risk analysis on internal corrosion of carbon dioxide pipeline steel with the influence of impurities
Authors: Zhang J
Published: August 2024

Under the increasing demand for safe operation and maintenance of supercritical CO2 pipeline transportation projects, this paper summarizes the synergistic mechanism of process parameters such as pressure and temperature on pipeline corrosion in current CO2 transportation pipelines. The critical phenomenon of water content affecting corrosion and the current research status of the intensification of CO2 corrosion by impurities such as O2, SO2, NO2, and H2S on typical pipeline steel corrosion behavior are summarized, aiming to provide theoretical guidance for the risk analysis of pipeline steel corrosion in CCUS engineering in China. Finally, based on practical engineering requirements, it is suggested that in future research, more attention should be paid to the impact of supercritical CO2 flow characteristics on pipeline corrosion risk.
Importance of nano-carriers, surfactant system, and their loading mechanism to improve the absorption and bio-availability of drugs: a review
Authors: Abdul Azeez Nazeer , Venkateshwaran Krishnaswami , Kandasamy Ruckmani , Saravanan Muthupandian , Sudarshana Deepa Vijaykumar
Published: August 2024

Improving the apparent solubility of poorly soluble therapeutic molecules with poor absorption into the circulatory system is a significant research question in drug discovery. This enhancement is achieved by delivering drugs through nano-carriers that provide apparent solubility with its surfactant. The effectiveness of a nano-carrier is relied majorly on its loading efficiency which is determined by the extent of interaction between the drug and the surfactants of the carriers. The loading effectiveness can be reckoned with a better understanding of the drug-surfactant conjugation mechanism. Hence this review comprehends the different nano-carriers, their appropriate surfactant systems, and the loading mechanism of drugs with surfactants through different bonds. Further, the current status and prospects of the nano-carriers are briefly summarized at last to expound on the significance of these nano-carriers in drug delivery.
Sensitivity optimization of monolithic integrated refractive index sensor based on grating LED
Authors: Gao Xumin , Yu Xuehui , Wu Dongmei , Xie Mingyuan , Shi Zheng
Published: August 2024

In this study, we present a potential ultra-thin refractive index sensor model that utilizes a monolithically integrated gallium nitride-based light-emitting diode platform. This light-emitting diode not only emits light but also detects changes in refractive index. The sensitivity of this sensor is defined as the response of light extraction efficiency to unit changes in refractive index. We have incorporated a one-dimensional grating on the surface of the light-emitting diode to investigate the effects of the grating’s modulation on the light field and the sensor’s sensitivity.Through strategic optimization of the grating structure, we have significantly enhanced the sensitivity of the sensor. Our results indicate that, compared to a conventional flat light-emitting diode, the optimized grating structure increases the light extraction efficiency by approximately 2 to 3 times. Furthermore, the sensitivity of the sensor has achieved a maximal enhancement of up to 41-fold.The device offers a compact design and demonstrates high levels of light extraction efficiency and sensitivity, making it highly suitable for monolithic integration in optical sensing applications. This advancement provides a substantial contribution to the field of optical sensing, indicating promising potential for future research and application.
Optimizing the drilling process parameters of AZ91 based hybrid composites using TOPSIS and grey relational analysis
Authors: P Hariharasakthisudhan , K Logesh , Kannan Sathish , R Sivakumar , K Sathickbasha
Published: August 2024

AZ91 is a popular magnesium alloy that contains aluminum (Al), zinc (Zn), and small amounts of other elements that offers a good balance of mechanical properties and corrosion resistance, making it suitable for various applications such as automotive, aerospace, sports, and biomedical. The current research works focused on optimizing drilling process parameters such as cutting speed, feed rate, a set of standard tools, and biofriendly coolants against the surface roughness and axial thrust force for AZ91/ nano hBN/ micron TiB2 hybrid composites. Taguchi L18 orthogonal array was used to design the drilling experiments. The axial thrust force and surface roughness of the drilled hole were observed as response of the experiments. Based on the results from TOPSIS and GRA, the optimal conditions were determined to be a spindle speed of 65 m/min, feed rate of 1 mm/rev, using a High-Speed Steel (HSS) tool, and Liquid Nitrogen (LN) coolant for 1 wt% of nano hBN in the hybrid composite. These parameters resulted in the lowest axial thrust force and surface roughness, highlighting their effectiveness in optimizing the drilling performance of AZ91/TiB2/hBN composites.
Evaluating cell growth and hypoxic regions of 3D spheroids via a machine learning approach
Authors: Yoo Jaekak , Choi Jae Won , Kim Eunha , Park Eun-Jung , Baek Ahruem , Kim Jaeseok , Jeong Mun Seok , Cho Youngwoo , Lee Tae Geol , Heo Min Beom
Published: August 2024

This study investigated the applicability of the area of spheroids and hypoxic regions for efficient evaluation of drug efficacy using machine learning (ML). We initially developed a high-throughput detection method to obtain the area of spheroids and hypoxic regions that can handle over 10 000 images per hour with an error rate of 2%–3%. The ML models were trained using cell growth of six cell lines (i.e. HepG2, A549, Hep3B, BEAS-2B, HT-29, and HCT116) and hypoxic region variations of two cell lines (i.e. HepG2 and BEAS-2B); our model can predict the area of spheroids and hypoxic region of certain growth date with high precision. To demonstrate the applicability, HepG2 spheroids were treated with sorafenib, and the efficacy of the drug was evaluated through a comparison of differences in areas of cell size and hypoxic regions with the predicted results. Furthermore, our ML approach has been shown to be applicable to provide the model-driven evaluative criterion for toxicity and drug efficacy using spheroids.
Painting with Falseness
Authors: Chan Eleanor
Published: August 2024

False relations are particularly found in sacred, vocal music; as a result, textuality is key to understanding how they were deployed. This chapter explores the false relation and its relationship to ideas about word painting, chromaticism, and expression, both contemporary and those still adopted in the twenty-first century. It argues that, rather than focusing on individual word groups and types (noun, proper noun, adjective, verb), a more productive reading can be gained by focusing in on phrasing patterns, the structure and semantics of rhetorical tropes, and the burgeoning forms of punctuation (‘distinction’ or ‘pointing’, in contemporary terminology). The false relations of the English Renaissance rose to prominence during the great push to establish a vernacular liturgy. As this chapter demonstrates, the syntax of the Book of Common Prayer (1549) and Whole Booke of Psalmes (1562) hold the key to reaching towards an understanding of the semantic, expressive role of the false relation.
How to Train Your Discord
Authors: Chan Eleanor
Published: August 2024

With the boom in how-to books across the sixteenth century, partial literacy and a broader readership are key to understanding false relations in the English Renaissance. The increasing availability of print sources, often adopting innovative graphic tactics for disseminating information, meant that expert and professional musical readers were no longer the only market for repertoire with false relations. Looking at two musical manuscripts which have been demonstrated to be explicitly didactic, the Hamond Partbooks and A Book of Solfaing Songes alias Add. MS 31390, this chapter examines how young choristers and amateurs learnt how to perform false relations, and the role that they played in general choral education. Through devices such as table books, canonic imitation, dialogic formats and writing, as well as performing, notation, it demonstrates that false relations served a key role in training aspiring musical readers and performers.
Afterword
Authors: Chan Eleanor
Published: August 2024

Love of the false relation continued into the seventeenth century, but increasingly it was used to signify allegiance to the English choral tradition, rather than for the variety of purposes it served in the sixteenth century and in the early decades of the seventeenth. This chapter considers the way that Restoration composers such as John Blow and Henry Purcell deployed false relations to political ends, as ways of signalling the native Englishness of their musical style. Under the aegis of James I and VI’s project to establish ‘Great Britain’, carefully mannered false relations became increasingly expedient ways to signify an embryonic musical whiteness. Finally, turning to Jacobean writers John Norden and Henry Peacham’s use of concord and discord as metaphors for native English rule, this chapter explores how thinking around false relations aided the development of the mythologized English-as-British past, and burgeoning theories of English exceptionalism that fuelled colonization.
Not daily, sometimes not ever – mixed methods exploration of the contemporary relevance of tasks contained in extended activities of daily living scales
Authors: Minnis Meghan , Burton Jennifer Kirsty , Kelbling Eline , Gallacher Katie I , Quinn Terence J
Published: August 2024

Background

Assessment of functional status is an integral part of older adult healthcare and research. Therefore, it is essential that tools to capture function are contextually appropriate. Many tools designed to evaluate extended Activities of Daily Living (eADLs) were developed decades ago.

Objective

Our aim was to explore which eADL tasks are commonly performed by older adults and map these tasks to popular eADL scales, seeking stakeholder perspectives to inform recommendations on scale content.

Design

Online survey with quantitative questions and free text followed-by semi-structured interviews.

Subjects

Older adults (≥60-years), carers and health, social care and voluntary/community professionals.

Methods

We extracted eADL tasks from existing scales to develop a survey on frequency of performance, with space for additional comment. The survey was disseminated via Join Dementia Research and other clinical and professional networks. Online semi-structured interviews were undertaken with thematic analysis of verbatim transcripts.

Results

From 2244 online survey responses, 87% came from older people and two-thirds of respondents were female. Some eADL tasks were never performed by many participants. Tasks not part of existing tools included online banking and mobile phone use. From fifteen interviews, a recurring theme was that technological and societal changes have altered daily tasks.

Conclusions

Commonly used eADL scales contain obsolete tasks and omit tasks older people consider part of their everyday lives. There is a need to work collaboratively to update eADL tools to reflect the priorities and activities of older people to ensure these remain valid measures for use in practice and research.

To complement this abstract, a video abstract is available online. A more detailed video-based summary of the content is also available as supplemental material.