bluuebunny/crossref_metadata_2025 huggingface dataset:
Newton and the genesis of Leibniz’s theory of space
Authors: Risi Vincenzo De
Published: November 2024

The paper in [1] provides a history of Gottfried Leibniz’s ideas about space. Contrary to standard readings, Leibniz did not develop a relational theory of space until 1688 when he read Isaac Newton’s Principia and realised that he had to respond to the theory of absolute space with a new, powerful and rich alternative theory. The paper details Leibniz’s theories of space prior to the relational theory and their philosophical sources. It discusses Leibniz’s theory in relation to his theories of time, motion and geometry. Finally, it shows the role of Newton in the genesis of Leibniz’s relational theory.
Kuhn’s paradigms and their early critics
Authors: Preston John
Published: November 2024

In his 1962 book The Structure of Scientific Revolutions, Thomas Kuhn fashioned and made fashionable the concept of a paradigm. He tied it closely to his concept of ‘normal science’ and contrasted normal science with processes he called ‘scientific revolutions’. Several important critics took issue with his concept of a paradigm or with theses he took to constitute that concept. In this paper the earliest criticisms of the concept are outlined.
Action at a distance: From Newton’s gravity to quantum theory
Authors: Jansson Lina
Published: November 2024

Isaac Newton’s theory of gravity seems to postulate action at a distance. Two distant massive bodies act on one another gravitationally instantaneously without a causal mechanism to mediate the action. This paper will argue that a strategy found in the Principia that allows Newton’s theory to be explanatory without providing a causal explanation can be extended to the quantum case. However, while causal action at a distance can be avoided, the explanatory cost of avoiding any form of nonlocality is higher in the quantum case than in the case of Newton’s theory of universal gravitation.
Does fine-tuning support the existence of a multiverse?
Authors: Wilson Alastair
Published: November 2024

In the context of the probabilistic fine-tuning argument for the existence of a divine designer, appeals to the existence of a multiverse have often seemed ad hoc. The situation is rather different though if there is independent evidence from physics for a multiverse. This paper argues that the fate of the fine-tuning argument depends on open questions in fundamental physics and cosmology. It also argues that the many-worlds interpretation of quantum mechanics opens up new routes to undercutting the force of the fine-tuning argument.
Scene-setting re scientism: How Wittgenstein helps us to properly appreciate physics without over-valuing it
Authors: Read Rupert
Published: November 2024

Some contemporary readings of Ludwig Wittgenstein consider him an opponent of science, but in fact Wittgenstein was a great admirer of ‘the scientific method’ so long as it did not overstep its boundaries. Wittgenstein was concerned that if the scientific method were seen as the only truth-collecting source, then it would be applied in places where it does not naturally fit, and thus encroach on the bountiful insights that subjects beyond the natural sciences can give us. Reflecting on the state of today’s society in general and research academies in particular, it is obvious that the ‘scientism’ that concerned Wittgenstein in the 20th century has only intensified into the 21st century. By reflecting on Wittgenstein’s writings, one can be more aware of this overreaching of the scientific method and more able to call it out when confronted by it.
The emergence of nanoscience
Authors: Baumberg Jeremy , Baumberg Cass
Published: November 2024

Nanoscience and nanotechnology have emerged as distinct scientific concepts in the final third of the 20th century, however the way that the history of this field is discussed has not settled into an accepted path. This paper discusses the many ways to approach this history, spanning science intuition, ancient technologies, mythical visions, tool development, commercial opportunities and science fictions. In the brief and accessible discussion here expanding on the different histories of nano, the paper explores some of these concepts and conclude that this is not (yet) a well posed question.
Controversies in physics
Authors: Butterworth Jon
Published: November 2024

This paper discusses various types of controversy in fundamental physics and why it is not always sufficient to simply wait for more data to resolve them.
Superluminal neutrinos: an OPERA in three acts
Authors: Cartwright Susan
Published: November 2024

In September 2011 the OPERA experiment at the Gran Sasso Laboratory, Italy announced that they had evidence that the neutrinos in the CERN-to-Gran-Sasso (CNGS) beam line were travelling very slightly faster than the speed of light. If true this would have ranked among the most important discoveries of the 21st century. In the event it was not true and was rapidly discredited. This paper explains what the measurement entailed, the responses to it and the eventual explanation, and discusses whether the initial publication and the subsequent reactions were appropriate.
Big Science: before and after the Manhattan Project
Authors: Kragh Helge
Published: November 2024

Although the concept of Big Science is not well defined, it is often identified with expensive and government-funded post-World-War II projects in physics and space research. However, this definition is too narrow both with regard to chronology and with regard to the sciences in question. Apart from offering some general comments on the notion of Big Science this paper adopts a historical perspective by singling out a few cases of pre-twentieth century Big Science projects in physics and astronomy. These were exceptions, however, and it was only with the Manhattan Project and the early generations of high-energy accelerators that the Big Science era truly started. As argued the development involved new forms of organisation as well as new ethical problems relating to the role and responsibility of the individual scientist.
Big Science “for the benefit of all mankind”
Authors: Bigot Bernard
Published: November 2024

A little more than a century ago at the turn of the 1920s two eminent scientists—Jean Perrin (1870-1942) in France and Arthur Eddington (1882-1944) in the United Kingdom—speculated that the energy source at the core of the Sun was a product of nuclear reactions. Their intuition was a huge departure from the theories that had prevailed until then. In the years that followed a clearer understanding1 of the hydrogen fusion process at the core of Sun-like stars led to a Promethean ambition: reproducing and harnessing fusion reactions to gain access here on Earth to a new sustainable source of energy for generating electricity on a massive scale.
Big Science in physics: a look at the decade ahead
Authors: Banks Michael
Published: November 2024

For decades Big Science facilities in physics and astronomy have attempted to answer some of the biggest questions possible – how did the Universe begin, how will it end, what are the fundamental constituents of matter? Tackling these questions has resulted in building bigger, ever more complex facilities. Yet with it comes costs and delays when pushing the boundaries of technological knowledge. This paper briefly reviews some of the big projects in physics and astronomy in recent years as well as looking at what lies ahead in the coming decade.
Microscopy and microbiology: Moving forward together
Authors: Hardie Kim R. , Self Tim , Markus Robert
Published: November 2024

For more than four thousand years technological advances have enabled us to see the invisible through the invention and development of microscopes that have delivered magnification alongside resolution. Over the same timescale this has led to the discovery of microscopic organisms and the birth of the science of microbiology. From ancient theories that an invisible life form existed light microscopy established their presence in the 1600s. Over the next couple of centuries light microscopes were developed with improved illumination and precision as microbiologists created ways to grow and sample their microbes. In so doing microscopy and microbiology extended our understanding of infection transmission from generalised miasma and germ theories to linking specific diseases with particular microbes to make diagnosis and prevention more reliable. Electron and fluorescent microscopy provided step changes in the visualisation of the finer detail of microbes, enabling the characterisation of internal structures and the unravelling of the molecular mechanisms of biological processes. We are now within an era of imaging microbes in three dimensions over time with sensitivity and super resolution to study the microbes in their natural habitat such as within infected tissues. With the advent of multi-modal, correlative and molecular imaging the future holds the promise of a full interrogation of the internal machineries of microbes and real-time tracking of their lifecycle and interactions. This will help deliver the next generation of antibiotics and alternative prevention strategies to enable everyone to live longer, healthier lives.
The greatest physics discovery of the 20th century
Authors: Phillips William D.
Published: November 2024

I have chosen Quantum Mechanics as the greatest physics discovery of the 20th century and in this brief paper I explain that quantum mechanics has changed the way we think about physics, the way we think about reality and the nature of our ordinary lives. I embrace the weirdness of quantum physics and its ability to calculate physical properties to amazing accuracy, along with the practical applications of the past and those to come, while marvelling at how much there is yet to be understood.
Galileo’s microscopic and telescopic observations and their impact on how bodies are conceived
Authors: Buyse Filip
Published: November 2024

Four hundred years ago Galileo Galilei published a work that was immensely successful directly after its publication but is relatively unknown today. The Assayer (Il Saggiatore) started as a polemic reply to Orazio Grassi’s interpretation of the first telescopic observation of comets in history. The Jesuit defended the idea that comets were bodies moving in the superlunary region. However, Galileo never explicitly stated that comets are an illusion or an optical defect. Rather he aimed at undermining Grassi’s argumentation. Consequently, what announced itself initially as a controversy about the nature of comets turned out to become a controversy about the nature of scientific methodology. This paper focuses on two elements that Galileo elaborates on in this pioneering work of scientific method: his views on the qualities of bodies and the fact that “the book of nature” is written in the language of mathematics. It demonstrates how these two elements are not only connected in The Assayer (1623) but also in his earlier work. In addition, it shows how they both played a role in Galileo’s defence of mathematical demonstration and his rejection of the tools of scholastic philosophy.
Why middle-sized matters: Quantum realism, minds and the Problem of Macro-Objects
Authors: Simpson William M.R.
Published: November 2024

The Problem of Macro-Objects concerns how three-dimensional, middle-sized objects, such as scientists and their measuring devices, can exist in a quantum world. This paper discusses the problem for wave function realism and the primitive ontology approach to quantum mechanics, focussing on Alyssa Ney’s recent two-stage solution, in which macro-objects are functionally reduced to micro-objects and micro-objects are parts of a whole in which they are grounded (the wave function field). It raises metaphysical difficulties with this proposal which a hylomorphic account of wholes may be able to address, noting possible implications for one’s philosophy of mind depending on one’s preferred solution to the Measurement Problem.
Evaluation of salt particle collection devices for coastal metal storage facilities with natural ventilation
Authors: Chen C K , Lin W J
Published: November 2024

Stress corrosion cracking (SCC) is a potential threat to metal containers stored in coastal facilities utilizing natural ventilation due to sea salt particles in the airflow. This study investigates the applicability of low-pressure salt particle collection devices developed by the Central Research Institute of Electric Power Industry (CRIEPI) in Japan (reports N08050 and N11044) to natural ventilation systems in Taiwanese coastal storage facilities. We evaluate the capture efficiency and pressure drop of these devices compared to conventional stainless steel filters. The pressure loss of the collection devices was assessed using the CRIEPI model and compared with a handbook model, demonstrating high agreement. Capture efficiency analysis revealed a reduction rate of approximately 78% for the salt particle collection device. However, peak analysis indicated this reduction was primarily effective for particles exceeding 10.2 μm in diameter. Compared to stainless steel filters, the collection devices offer lower reduction efficiency but with a stable pressure drop and potentially lower maintenance costs. This study also emphasizes the need for optimizing salt particle reduction methods by considering the trade-off between capture efficiency and pressure drop.
The investigations of asperity peaks and surface roughness on transient squeeze elastohydrodynamic lubrication
Authors: Chu L M , Hsieh M J , Chang Y P
Published: November 2024

The effects of asperity peak contact pressure and surface roughness (SRN) on pure squeeze elastohydrodynamic lubrication (EHL) motion of circular contacts are investigated for fixed load by using Gauss-Seidel iteration method (GSIM) and finite difference method (FDM). The transient pressure, asperity peak contact pressure, elastic deformation, and film thickness during the pure squeeze process under distinct operating conditions in EHL regime are studied. The results indicate that the differences of the pressure and film thickness between SRNEHL model and EHL model are apparent in final stage due to elastic asperity peak contact. The asperity peak contact pressure will affect hydrodynamic pressure for fixed load, so the hydrodynamic pressure with roughness surface is smaller than that without roughness surface especially around the Hertzian contact (X=1) edge. These phenomena result in different changes in total pressure in different areas. For the contact region, the film thickness of smooth type (ST) is greater than those of circular roughness type (CRT), but this phenomenon reverses near X=1. The larger the C value, the earlier the asperity peak contact effect. Therefore, the greater the C values, the greater the asperity peak contact pressure, and the smaller the hydrodynamic pressure. The asperity peak contact effect significant changes many phenomena at contact region in squeezing final stage.
A study on the feasibility of friction stir welding in joining dissimilar metals for SS400 and Ti-6Al-4V
Authors: Hsieh M J , Chu L M , Chang Y P
Published: November 2024

This study designed friction stir multi-pass welding machine to conduct friction stir welding on carbon steel/titanium alloy clad sheets. The experimental process utilized the pin and pinless tools. The results demonstrate that the two dissimilar materials can be welded using the assembly-embedded rod pinless tool under the following welding conditions: a rotational speed of 1200 rpm, a downward force of 4 kN, a welding speed of 15 mm/min, and tool offset distances of 5 and 10 mm. Furthermore, this study investigated the microstructure and mechanical properties of the weld. In addition, the peak temperature measured at the joint interface exceeded the β phase transition temperature of the titanium alloy and surpassed 1000°C. The shear tensile test shows the weld’s failure load was about 4300 N. The intermetallic compound at the welding interface has a microhardness value of approximately 400 Hv. According to the results of SEM observations and EDS composition element analysis, the elements of low carbon steel and titanium alloy at the interface of the clad sheet diffused and formed Fe-Ti intermetallic compounds.
Forming limit analysis of magnesium alloy sheet metal forming process at elevated temperatures
Authors: Yang T S , Huang J Y
Published: November 2024

Magnesium alloys are valued by industry for their lightweight structures. Magnesium alloy are mainly produced by warm forming because the sheet formability is poor at room temperature. The mechanical properties of magnesium alloy AZ31, such as stress-strain curves and damage values at different elevated temperatures, were obtained by this study using a computerized screw universal testing machine. Freudenthal fracture criteria were used to obtain the forming limit at distinct temperatures. The forming limit analysis proceeded during the sheet metal forming process at various elevated temperature. The fracture’s forming load, stroke, and position were determined for different working temperatures of the sheet metal forming process for AZ31, using a finite element simulation combined with the ductile fracture criteria. Finally, the predicted values were compared with the experimental results during the sheet metal forming process. The simulation results agreed with the experimental values for the fracture forming load, stroke, and position of the sheet metal forming process. The feasibility of the present method was confirmed to predict forming limit during the sheet metal forming process for different elevated temperatures. A finite element analysis for forming limit prediction would be beneficial to the design of sheet metal processes for AZ31 magnesium alloys.
An IoT platform for smart metal forming
Authors: Yang M
Published: November 2024

Manufacturers in the metal forming industry are paying attention on smart manufacturing with the industrial internet of things (IIoT). An innovation has been occurring by changing metal forming processes from analog to digital by utilizing servo press machine and IT technology for improving efficiency and worth of the mass production manufacturing technology and of ability for the SDGs. This paper aims to introduce initiatives to survey of the current situation and formulation of strategies on the digital transformation in metal forming promoted by the Sokeizai Centre in Japan. An IoT platform for smart metal forming which has been developed based on the strategies is also introduced. The platform consists of sensor system for visualization of forming processes, sensor data wireless communication using local 5G and data assimilation with process simulation. Several sensing systems developed for process visualization are introduced.
Design and application of visualized quick-change molds
Authors: Chiu C H , Wu J C , Lu J R , Su W Y , Chen C C
Published: November 2024

In the process of plastic injection moulding, the flow behaviour of plastic within the mould is a critical factor in product formation. Achieving stable mass production requires iterative experimentation to adjust mould and machine parameters. This process incurs significant material, time, and labour costs. Therefore, this study focuses on the design of mould visualization and rapid mould exchange. By visually observing the plastic flow during product formation, this study can make preliminary and intuitive judgments for real-time adjustments. Leveraging the convenience of rapid mould exchange, observations and experiments on multiple product iterations are made, effectively reducing the time and cost associated with mould replacement.
Analysis of load flow based on power system analysis software package by using the IEEE 30-bus system
Authors: Hsu W T , Liang L W , Yang C C , Huang C W
Published: November 2024

A power-flow study is a numerical analysis to judge the stability of the power system during operation. By analyzing the results of the load flow calculations, the transmission line, the load distribution, the power factor, the equipment capacity, the distribution network, and the power quality and reliability of the distribution network are improved. This paper uses the IEEE 30-Bus system as an example of building a modified system via the power system analysis software package (PSASP) for the power-flow study. Other simulation tools are validated by using the MATPOWER toolbox and MATLAB/Simulink. The result of the load flow calculation for the three simulation tools is almost consistent, so the practicability of the tool is proved. It is verified that the PSASP is one of the reference simulation tools for power system analysis.
Design and application of graphite film with high thermal conductivity in SAR antenna
Authors: Zhu Shangkun , Shang Xiuyu , Xu Jiyuan , Kong Xiangju , Qian Jiyu , Wei Tao
Published: November 2024

The rapid development of SAR antenna in the remote sensing field has put forward the test of antenna thermal design. In this paper, according to the load of a certain type of extravehicular SAR antenna, a reasonable thermal design is carried out for its high heat consumption and external heat flux. A high thermal conductivity graphite film is used for heat expansion. The test shows that the mounting plate heat expansion capacity difference is 28°C with and without graphene film, with 40W heat consumption applied in 180mm transmission distance. The simulation analysis and thermal balance test are carried out. The results show that the high thermal conductivity graphite film can rapidly extend the heat of the single unit of the SAR antenna to the whole antenna, and make the antenna meet the temperature requirement in orbit, which proves the rationality of thermal design. This paper is useful for the thermal control design of a satellite-borne SAR antenna.
Numerical simulation of influence of jet flow parameters on cone-cylinder-flare configuration
Authors: Chen Jin , Sun Ruibin , Zhang Jiayue
Published: November 2024

Reaction control system technology is used to realize attitude control or trajectory change. The hot jet effect should be considered to get more accurate aerodynamic characteristics as the flight vehicle develops. The simulation for hot jet flow needs more calculation resources, so it is important to research the suitable similarity parameters of jet flow. Then, we can use cold jet flow to simulate hot jet flow. In this paper, the influence of jet flow parameters is numerically studied on cone-cylinder-flare configuration. The numerical simulation method for hot jet flow is established, containing finite volume method, multi-component three-dimensional Reynolds Navier-Stokes equation with source terms, multi-block patched grid technique, and fully implicit processing method. The numerical method is verified by using experimental reference results, and the grid independence is assured. The numerical results reveal that the cold jet flowfield under the same mass flow ratio is more similar to the hot jet flowfield than the cold jet flowfield under the total temperature of 293 K. The maximum amplification factor difference between cold and hot jet flow is reduced from 14.1% to 1.2%.
Design and application of deployable heat radiator
Authors: Li Jin , Zhao Qiwei , Zheng Hongyang , Zhang Yang , Yu Xingang
Published: November 2024

Limited by the envelope size of the launch vehicle, comparing with the body-mounted radiator of the traditional spacecraft, the thermal control scheme based on single-phase fluid loop is proposed in order to improve the system-level heat dissipation. The thermal analysis model of the deployable heat radiator, including the spacecraft, is established. Through the comparative analysis of the fin parameter, infrared radiation effect, and working fluid selection, the heat dissipation efficiency of the radiator is improved, and the first flight application of the deployable heat radiator is realized. The research results show that in view of the GEO spacecraft’s bad external heat flow condition, the heat dissipation of a single radiator can reach 250W/m2 above; the method of using multiple deployable heat radiators can effectively solve the problem of insufficient heat dissipation capacity on the spacecraft.
Research on the qualification of TQL-5 COTS Tools in airborne software reliability verification process based on DO-330
Authors: Fan Hui , Hua Hui , Liu Jianfang
Published: November 2024

The rapid development of airborne software is inseparable from the help of tools, especially the TQL-5 (Tool Qualification Level 5 based on DO-330) COTS (commercial off-the-shelf tools) tool, which is the most widely used. It is worth noting that to ensure software reliability and safety, the tool also needs to be qualified. Based on the DO-330 standard, this paper introduces the qualification methods for COTS tools, TQL-5 tools, and TQL-5 COTS tools, focusing on how to qualify TQL-5 COTS tools and the objectives that tool developers and users need to meet. It plays a guiding role in the airworthiness of airborne software tool users and tool developers.
Directional control law functional analysis and design for civil aircraft simulator
Authors: Xie Gangtao , Chen Lei , Qu Xiaoyu
Published: November 2024

Functional analyses of directional flight control law for a typical civil aircraft are conducted, including directional maneuver, rudder limiter, coordinated turn, Yaw Damper, Thrust Asymmetrical Compensation, Gust Alleviation, manual rudder trim, etc. Through inputs of doublet, step input, and sweeping frequency, open loop control characteristics are analyzed based on a linearized state-space matrix. Simulink block architecture of a closed-loop directional control law is constructed, aiming to fulfill flight control functions, including pedal-to-rudder control, Yaw Damper, coordinated turn, and gain-tuned rudder limiter. Simulations for the previously designed closed-loop directional control law are performed to verify the characteristics of directional handling qualities in the aspect of the Yaw Damper, directional static and dynamic stability, maneuverability, and sweeping frequency.
Study on cross effect of mesh and turbulence model on separated flow prediction using a tandem cylinder case
Authors: Pang Chao , Wang Tao , Ba Weitao , Lv Shuiyan , Xie Botao
Published: November 2024

Low dissipative separated flow prediction is still a great challenge in aeronautics engineering. An open-source CFD code named SU2 is employed to study the cross effect of mesh as well as turbulence model on the numerical resolution of separated flow for a tandem cylinder case. Firstly, a nonlinear variation of the numerical resolution for the separated flow is found by comparing the mean surface pressure distribution, mean streamwise velocity profile, the instantaneous vorticity magnitude as well as the aerodynamic forces on the rear cylinder. The resolution of separated flow from the medium mesh is the best compared to those getting from the coarse and fine mesh. Secondly, the reason causing the nonlinear variation of flow resolution is analyzed considering the influence of spatial discretization error and turbulent viscosity locally. A finer mesh would lead to a low spatial discretization error and then a high turbulent viscosity and then causes nonlinear variation of flow resolution. Finally, the existence of a “density boundary” of the mesh is proposed which could balance the spatial precision as well as turbulent viscosity and achieve the prediction of separated flow with a good resolution employing the RANS method.
Optimization of embedded sensor placement for small satellites
Authors: Sun Hao , Yue Zhongwen , Liu Chuang , Wu Wenhua , Peng Jinkun , Li Yi , Ren Zhiqiang
Published: November 2024

Dynamic environment testing is important in the manufacturing phase of a satellite before launch. However, redundancy is introduced into the testing by the massive placement of vibration sensors inside and outside the satellite, adversely affecting testing efficiency, especially in the development of satellite constellations. An intelligent algorithm-based sensor optimization method is proposed to maximize the relationship between measure points and reduce the number of internal sensors while ensuring the independence of external sensors. A frequency response matrix of internal and external sensors is constructed through a frequency-sweeping analysis of the satellite structure. Subsequently, external sensors are categorized into different groups by using principal component analysis (PCA) and K-means clustering analysis. A modified information entropy approach is applied to optimize the quantity of internal sensors. Through the practical application of sensor reduction in a specific satellite, the proposed method achieves a good reduction result.
The properties of axion with three different sets of parameters in two flavor Nambu-Jona-Lasinio model
Authors: Zhao Wenhao , Zhu Yuqi
Published: November 2024

While the properties of axions have been studied primarily through high-energy physics and cosmology, there are some potential connections between the research results and the aerospace field. We study the properties of axions in hot and dense matter with three different sets of parameters in the Nambu-Jona-Lasinio model, including axion mass and self-coupling. We discussed axion mass and self-coupling, noting that axion properties are very sensitive to chiral phase transitions for three sets of parameters. The axion mass and self-coupling rapidly decrease in the chiral crossover region. The value of self-coupling becomes very sharp, appearing as a kinklike feature in the chiral phase transition.
Dynamic model decomposition study on the influence of cutback surface length on the wake characteristics of turbine blades
Authors: Luo Yuxi , Wen Fengbo , Wang Songtao , Guo Licheng
Published: November 2024

The flow within a cascade of pressure-side cutback cooling blades with different cutback surface lengths is predicted using the unsteady numerical method. Dynamic Mode Decomposition (DMD) is used for flow field order reduction analysis. The relationship between varying cutback surface lengths and the wake dynamics is analyzed. The analysis shows that the shear layer behind the trailing edge and lip dominates the unsteady flow in the wake region. As the cutback surface length diminishes, an increase in the modal frequencies of both the lip shear layer and the wake shear layer is observed. As the cutback surface length is shortened, the shear layer behind the lip causes stronger oscillations in the shear layer behind the trailing edge, subsequently leading to an augmentation in the amplitude width of the wake mode across the transverse direction.
Research on trajectory planning based on deep reinforcement learning
Authors: Zhou Zan , Hu Runchang , Gong Zheng , Zhang Zhuhua
Published: November 2024

For trajectory planning in a three-dimensional continuous space with multiple complex constraints, traditional optimal control methods face significant challenges, such as long computation times and poor dynamic performance. Using deep reinforcement learning algorithms for training agents in flight trajectory planning can effectively improve the dynamic performance of the planning algorithms. This paper focuses on training agents for UAV emergency landing and obstacle avoidance trajectory planning based on deep reinforcement learning algorithms. Within the reinforcement learning framework, we design the training environment, state space, action space, reward function, and neural network structure. To address common issues in reinforcement learning, such as poor generalization and slow training speed, we improve the training process using the concept of curriculum learning. Comparisons with pseudospectral methods demonstrate that deep reinforcement learning can effectively handle trajectory planning tasks in real flight environments, achieving trajectory quality close to that of pseudospectral methods while offering superior real-time performance.
Simulation of the electromagnetic scattering characteristics in inductively coupled plasma array for aircraft stealth
Authors: Guan Yong , Zhang Zhengquan
Published: November 2024

In this paper, an electromagnetic model of an inductively coupled plasma (ICP) array is developed to investigate its electromagnetic transmission characteristics under varying discharge conditions. The reliability of the model is enhanced by basing plasma parameters on simulation results from a fluid dynamics model. Electromagnetic simulations analyze the reflection spectrum of the inductively coupled plasma array, revealing the modulation mechanism of the plasma array. Findings indicate that as excitation power increases, the attenuation peak of the ICP array shifts to higher frequencies, and the attenuation bandwidth widens. By employing different power levels for the two layers in the Inductively Coupled Plasma (ICP) process, the array can achieve effective stealth performance with lower power consumption. Adjusting plasma discharge parameters to match specific scenarios enables the proposed plasma array to achieve varied modulation effects, expanding its potential applications in aircraft stealth.
Transient dynamics simulation of helicopter tail transmission shaft damage
Authors: Yuan Rongyi , Yang Kai
Published: November 2024

Using the LS-DYNA explicit dynamic analysis software, a finite element model of projectile damage in helicopter tail transmission shaft was established with the Johnson-Cook intensity model. The dynamic response of the tail transmission shaft during bullet penetration was simulated dynamically, revealing that projectile damage is the primary mode of failure. Three typical angles were selected to simulate the penetration process, and results indicate that compared to vertical and 45°bullet penetrations, tail transmission shaft damage is more severe.
Research on background heat flux of the thermal balance test system based on solar simulator
Authors: Gao Qingzhe , Wu Dongliang , Wang Runze , Lin Boying , Li Xiyuan , Xu Yantong
Published: November 2024

In the thermal balance test system based on the solar simulator, the background heat flux of the test system can cause additional heating to the spacecraft, reducing the effectiveness of the thermal test. Hence, it is necessary to conduct in-depth research on the impact of background heat flux through experimental and numerical methods. This paper first measures the background heat flux of the thermal test system based on the KM6 large-scale solar simulator experimentally, which is 35W/m2. Then, a simulation model of the thermal balance test system is established to clarify that the background heat flux originates from the cone chamber and collimating reflector of the solar simulator system. The result provides technical support for achieving a high-precision simulation of the space external heat flux based on the solar simulator.
Study on the aerodynamic characteristics of reentry capsule with obtuse head inverted cone under hypersonic chemical nonequilibrium flow
Authors: Sun Bin , Chen Weiyue , Huang Cai , Long Yin , Diao Weihe , Zhang Huiwen
Published: November 2024

During spacecraft reentry, the aerodynamic characteristics of the reentry capsule with a sizeable obtuse head inverted cone (OBHIC) in a hypersonic state are the key factors in the design of controlled reentry trajectory, the design of trim angle of attack (AoA), and the accuracy of fall point of capsules. This paper establishes a numerical simulation algorithm of a hypersonic chemical nonequilibrium flow field by considering high-temperature real gas effects. The reentry capsule’s aerodynamic and flow field characteristics are predicted and analyzed. The component transport equations for chemical reactions are added to the Navier-Stokes equations, enabling precise modeling of gas molecule vibrational excitation and ionization processes. A half-model multi-block structured mesh is employed to construct the aerodynamic profile of the reentry capsule with OBHIC. The aerodynamic characteristics and pressure distribution of the reentry capsule were calculated and analyzed under the typical conditions of flight altitude of 40~80 km, flight velocity of 6~27 Ma, and AoA of 15°~24°. The results of the aerodynamic characteristics prediction show that the aerodynamic characteristics of the reentry capsule are little affected by the incoming flow velocity in a hypersonic state but significantly affected by the AoA. As the AoA increases, the lift coefficient CL
increases linearly, the drag coefficient CD
decreases linearly, the lift-to-drag ratio K rises linearly, and K increases from 0.19 to 0.29. In its hypersonic state, the reentry capsule exhibits a low lift-to-drag ratio, characterized by high drag and low lift coefficients. The results of this paper play an essential role in the reentry flight dynamics and reentry trajectory design of the reentry capsule. Moreover, it can further ensure the safety and reliability of the reentry flight of spacecraft.
Modeling method of random collision of ellipsoidal particles in mechanical simulation for high energy solid propellant
Authors: Ma Xuhang , Li Chuntao , Jiang Pengchen , Xu Fangyi , Song Xiangyu , Li Wei
Published: November 2024

It is based on the molecular dynamics algorithm of elliptical optimization to establish a mesostructure model of oval particles of high-energy solid propellant considering gradation and controllable filling rate according to the mesostructure characteristics of high-energy solid propellant. The bilinear cohesion model was applied to describe the interface damage behavior and carry out the high-energy propellant tensile test at three rates. The rationality of the elliptical particle model has been verified between the comparison of the calculated results with the experimental results established to describe the micromechanical behavior of high-energy propellants, which is to reveal the mesoscopic damage law of high-energy solid propellant under different tensile rates in this paper.
Heat flux measurement at hypersonic turbulent separated flow field induced by the blunt fins
Authors: Ma Jikui , Liu Yaofeng , Liu Yuwei , Shi Jun
Published: November 2024

Hypersonic separated flow induced by the protrusions is one of the most concerning research studies in aerodynamics due to the complex flow structure and the significance of engineering. An experimental study of three-dimensional hyper-sonic separated flow induced by the blunt fins is investigated. The tests are performed with inflow Mach number 6. The main flow properties of the shock systems are described by analyzing Schlieren photographs. The heat flux data are obtained by using high precision platinum film sensors. The effects of the fin sweep angle are also presented. Results show that the maximum heat flux decreases, and the range of the separation zone quickly reduces as the swept angle increases. Low-frequency oscillations of separated flow fields are analyzed through instantaneous heat flux signals at typical measuring points. It is shown that characteristic frequencies of shock wave oscillation with no rear sweep angle is about 1 k Hz.
Nanodosimetric investigation of the track structure of therapeutic carbon ion radiation part2: detailed simulation
Authors: Schwarze Miriam , Hilgers Gerhard , Rabus Hans
Published: November 2024

Objective a previous study reported nanodosimetric measurements of therapeutic-energy carbon ions penetrating simulated tissue. The results are incompatible with the predicted mean energy of the carbon ions in the nanodosimeter and previous experiments with lower energy monoenergetic beams. The purpose of this study is to explore the origin of these discrepancies. Approach detailed simulations using the Geant4 toolkit were performed to investigate the radiation field in the nanodosimeter and provide input data for track structure simulations, which were performed with a developed version of the PTra code. Main results the Geant4 simulations show that with the narrow-beam geometry employed in the experiment, only a small fraction of the carbon ions traverse the nanodosimeter and their mean energy is between 12% and 30% lower than the values estimated using the SRIM software. Only about one-third or less of these carbon ions hit the trigger detector. The track structure simulations indicate that the observed enhanced ionization cluster sizes are mainly due to coincidences with events in which carbon ions miss the trigger detector. In addition, the discrepancies observed for high absorber thicknesses of carbon ions traversing the target volume could be explained by assuming an increase in thickness or interaction cross-sections in the order of 1%. Significance the results show that even with strong collimation of the radiation field, future nanodosimetric measurements of clinical carbon ion beams will require large trigger detectors to register all events with carbon ions traversing the nanodosimeter. Energy loss calculations of the primary beam in the absorbers are insufficient and should be replaced by detailed simulations when planning such experiments. Uncertainties of the interaction cross-sections in simulation codes may shift the Bragg peak position.
Bubble defect detection for tire shearography images with transfer learning based deep CNN models
Authors: Saleh Nagmy A A , Al-Areqi Farid , Konyar Mehmet Zeki , Kaplan Kaplan , Öngir Semih , Ertunç H Metin
Published: November 2024

Safety of drivers and passengers is an important quality assurance aim of the tire manufacturers. Tires that have air bubbles in them are a frequent cause of accidents. Recently, manufacturers have placed a high value on employing laborers with tire diagnostic experience. Along with the expenditure of time and money, this process also necessitates a sizable workforce of experienced laborers. The detection of tire defects can be automated utilizing a number of different ways, greatly reducing the margin for human error. One such method is digital shearography, which can be used to detect air bubbles in images. In this study, transfer learning based models are proposed to classify air bubble defects in tire shearography images. Proposed method employed in transfer learning with several deep learning CNN-based models, including VGG16, VGG19, ResNet50, Xception, MobileNetV2 and DenseNet201. Owing to the assistance of the experts at the Pirelli Automobile Tires Izmit factory, we were able to collect and label the dataset used in this study. The dataset contains 1392 tire shearography images. 811 of these images belong to the ‘good’ class, while the remaining 581 images belong to the ‘bad’ class. The proposed method in this study achieves remarkable bubble detection results over 95% in terms of accuracy and other metrics with the DenseNet201 model. The results indicate that the proposed model has comparable accuracy and recall with the existing studies. This study is valuable for the tire industry, as the existing literature offers limited research on the classification of tire bubble defects, the differentiation between defective and defect-free tires, and the categorization of various defect types. In addition, the proposed model offers several advantages over existing studies, including higher robustness against overfitting, suitability for real-time industrial applications, and improved efficiency in processing, making a practical solution for defect detection in industrial settings.
Investigation of excellence in Nd-YAG laser cutting of Al6061-T6 thin sheet using GRA coupled with PCA
Authors: Sharma Amit , Joshi Priyanka , Bhuyan Basanta Kumar , Phanden Rakesh Kumar
Published: November 2024

Cutting flying materials with minimum deviations and metallurgical damages is always preferred for airframe work in aircraft industries. In the present scenario, the laser cutting process has become the preferred choice for fine cutting of sheet materials with close tolerances. This paper reports the investigation of excellence in pulsed laser cutting of Al-alloy (Al6061-T6) sheet. Five quality characteristics for quantifying the dimensional accuracy (i.e., kerf width and deviation at the top and bottom side) and metallurgical damage (i.e., heat-affected zone) have been considered for the proposed work. These characteristics depend on the lamp current, laser parameters (pulse width and frequency), and relative motion between the sheetmetal and laser source. The experiments were performed using the design of the experiments technique. Further, the results of laser cutting have been optimized by using grey relational analysis (GRA) coupled with principal component analysis (PCA). The application of GRA-PCA is found capable of optimizing all five process responses at a time. The unevenness within the kerf is reduced by 22% and 32% at the top and bottom sides, respectively.
Max Weber, Imperialism, and the Fate of Globalization
Authors: Derman Joshua
Published: November 2024

This chapter reconstructs Weber’s theoretical understanding of the global economy and its relationship to imperialism at the turn of the twentieth century. Competing interpretations of Weber tend to depict him, in binary fashion, as either a proponent of imperial autarky or a defender of liberal globalization. A close analysis of Weber’s 1897 rebuttal of the economist Karl Oldenberg shows that neither interpretation does justice to the nuances of his thought. Weber believed that both international conflict and economic interdependency would remain ineradicable features of world order. Despite the inevitable growth of geopolitical tensions and the waning of public confidence in “free competition,” Weber predicted that great powers would remain dependent on a global, albeit increasingly militarized international economy. While Weber’s diagnosis has not always corresponded to the realities of twentieth-century international history, the uncanny parallels between his vision and the present crisis of international order are worth considering.
Introduction
Authors: Holo Selma
Published: November 2024

This chapter explores the role of the visual arts in human flourishing. It considers the expansive nature of the visual arts and the impossibility of caging them in traditional definitions. The visual arts can stimulate creativity, inspire, encourage contemplation and empathy, expand the limitations of reality, and enable those who respond to them to live their lives more generously and more generatively. Moreover, for artists, flourishing is the most desired state of being, especially since well-being sits a little deeper than happiness in the human psyche. The chapter then considers the potential for intersectionalities of human flourishing with the visual arts and its subsequent problems that might hinder flourishing in the long run.
“Art,” “Well-Being,” and Questions Without Answers
Authors: Ingold Kate
Published: November 2024

This chapter discusses the interplay of art and well-being. It starts with the phenomenon of Stendhal syndrome while referencing the people suffering from heart attacks while viewing Botticelli’s The Birth of Venus. The perception of art is subjective, especially when one artwork might be viewed as threatening while another could be seen as edifying. Moreover, the presence of art is one of the hallmarks of human-occupied prehistoric sites. The chapter looks into the constant need to assert the utilitarian role of art, such as the symbology for religion, political alliance, and group cohesion. It provides an overview of how well-being and flourishing affect art before considering the impact of art on well-being.
All Artists Are Poor
Authors: Campbell Andy
Published: November 2024

This chapter examines the correlation between economic justice and human flourishing. Beverly Buchanan’s business card and its list of expansive skills present her approach to making art that unveils the visibility and invisibility of poverty’s persistence coursing under the more common art theoretical and aesthetic discourses. The chapter explains that ensuring the contribution of art to general human flourishing would require providing artists with pathways to real and lasting economic stability. It highlights the significance of poverty affecting every single aspect of a person’s life and stability. However, the problem of art’s devalued position in the United States remains achingly apparent despite the scarcity of poverty as a critical hermeneutic.