bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Gas Lift on Oil Drainage Area in Reservoirs
Authors: Alikishiyev Ali , Eyvazov Jabrayil
Published: November 2024

Gas lift is a widely employed artificial lift method in the oil and gas industry, with the potential to significantly impact oil recovery from reservoirs. This study investigates the effect of gas lift on the oil drainage area within reservoirs, aiming to enhance our understanding of its role in reservoir management. Using advanced reservoir engineering and simulation techniques, the research explores the dynamics of gas lift and its influence on the accessibility of hydrocarbon resources.

The study provides a comprehensive analysis of gas lift parameters, including gas injection rates, depths, and configurations, and their collective impact on the drainage area. It also considers the interplay between gas lift operations and reservoir characteristics such as permeability, porosity, and fluid properties.

Findings from this study reveal that gas lift can effectively expand the drainage area by reducing bottomhole pressures and facilitating the movement of oil within the reservoir. This expansion enables the recovery of hydrocarbons from previously untapped regions, resulting in improved oil production. The research underscores the importance of optimizing gas lift design to maximize reservoir performance.

Additionally, the study addresses operational challenges associated with gas lift, including gas allocation, injection optimization, and equipment reliability. It provides insights into the economic and operational considerations of gas lifts, offering valuable recommendations for reservoir management.

The outcomes of this research contribute to a deeper understanding of how gas lift influences the oil drainage area in reservoirs, providing valuable insights for reservoir engineers, operators, and industry professionals involved in oil production. This knowledge supports informed decision-making to optimize oil recovery, reservoir performance, and the efficient use of gas lift technologies.
Optimization of The Development Plan for Ultra-low Permeability And Weak Volatility Reservoir
Authors: Zhang Mei , Sun Mei-feng , Wang Wen-hong , Cui Yun-hua , Han Xiang-hui , Cai Fen
Published: November 2024

Block F1 of F oil field belongs to ultra-low permeability volatility reservoir. Compared with similar reservoirs at home and abroad, the reservoir property of this block is poor and the permeability is only 1.4 mD. There is no development experience for reference. It is urgent to explore the effective utilization technology of volatility reserves in F oil field. In view of the problems that the preliminary research results of F1 block cannot meet the development needs, the reservoir research is not deep, and the development rules are not clear, Through fine structural interpretation and reservoir prediction, the geological characteristics of the oil reservoir have been clarified; We used multiple indicators to evaluate the initial production capacity of the block, And clarified the initial development rules of the weak volatility reservoir. Perfect the dynamic analysis and production capacity evaluation technology of weak volatility reservoir. By using the reservoir engineering method, we optimized the reasonable working system and the development plan. So we expanded the potential of block development, adjustment and external expansion and optimized the development plan, then we constructed the rational well network deployment technology of weak volatility reservoirs which can provide guidance for the effective development of the F1 block. The results can provide reference for the development of other ultra- low permeability weak volatility reservoirs.
Discussion on the development practice of low permeability reservoir of beach bar in saltwater lake basin—Take Wu5 block of Wunan Oilfield in Qaidam Basin as an example
Authors: Jia Fengjuan , Lin Chang Qing , Zhao Wenkai , Liu Le , You Chao
Published: November 2024

Based on the analysis of field outcrops, drilling cores, casting thin sections, logging interpretation, and development characteristics in the southwestern region of the Qaidam Basin, combined with the sedimentary characteristics, development patterns, and injection production well networks of the Neogene saline lake facies beach and dam in the southwestern region of the Qaidam Basin, his study aims to optimize the displacement system and improve the production rate. This paper counters the difficulty of Severely reservoir heterogeneity and interlayer contradictions low producing degree of water drive utilization and unclear understanding of water drive pattern in the study area; the article adopts Reservoir Engineering Methods, applies water injection development displacement and well network optimization evaluation techniques and bases on the geological characteristics of the reservoir to conduct the first time small well spacing pilot test in Block Wu 5, The results confirm that small well spacing encryption is feasible in this block.Therefore, the deployment and adjustment of small well spacing well network encryption in high structural areas of the area. Through implementation in the past two years, The small well spacing encryption in low-permeability sandbar reservoirs can effectively reduce seepage resistance, increase effective driving capacity, improve recovery rate and recovery rate, improve reservoir development efficiency, and increase economic benefits.
Numerical simulation of the impact of casing on the buried metal pipeline cathodic protection potential
Authors: Yao Jing , Hao Chengming , Xiang Xiaosen , Wang Shuli , Huang Shiqing , Rao Yongchao
Published: November 2024

Metal casings shield the cathodic protection current and detection signals of buried metal pipelines, making the corrosion protection and detection technology of pipelines at the casing one of the challenges for safe operation and integrity evaluation of pipelines. This paper uses the primary current distribution physics interface in the COMSOL Multiphysic simulation software to study the effects of the coating quality of the casing and pipeline, the installation of sacrificial anodes in the casing, the conductivity of the electrolyte, and defects in the pipeline coating in the casing on the pipeline potential. The influence of distribution. The results show that: The coating quality of the outer surface of the casing and the pipe inside the casing has a great influence on the cathodic protection potential of the pipeline. The better the coating quality, the more negative the cathodic protection potential is, and the less cathodic protection current required by the pipeline, so the power consumption of the forced current law is reduced, and the service life of the sacrificial anode is longer. Installing sacrificial anodes in the casing has a positive effect on the cathodic protection of this special pipe section. The conductivity of the electrolyte in the casing has a certain impact on the cathodic protection potential of the pipeline. When the conductivity of the internal electrolyte is greater, the protective potential of the pipeline becomes more negative. However, impurities such as soil, groundwater, and silt make the pipeline more susceptible to corrosion, so keeping the annular space relatively dry is an important prerequisite for anti-corrosion. When there is a coating defect on the inner and outer pipes of the casing, the potential at the damaged point will have a potential peak. The larger the potential peak difference, the more serious the coating defect is.
Birds of passage: Rudolf Peierls and Dick Dalitz in Oxford
Authors: Hey Tony
Published: November 2024

This paper traces the different routes that Rudolf Peierls and Dick Dalitz travelled on their way to being the founding members of a new Department of Theoretical Physics in Oxford. Peierls had had the good fortune to meet all of the originators of modern quantum mechanics in Europe and had been able to apply the new theory to many areas of physics. At Birmingham with Otto Frisch he wrote the famous Frisch-Peierls Memorandum which showed that it was possible to develop an atomic bomb. Dalitz had a shorter route to Oxford and worked with Peierls at Birmingham and Hans Bethe at Cornell before rejoining Peierls in Oxford after seven years in Chicago. His pioneering work on both the τ-θ puzzle and on the constituent quark model are then briefly described. The efforts of both Rudolf and Genia Peierls to create a ‘Bohr extended family’ model for his department in both Birmingham and Oxford are described, along with some observations about their style of theoretical physics research as ‘phenomenologists’.
Globalisation: The physics landscape today
Authors: Wheater John
Published: November 2024

This paper discusses how physics has become globalised in the context of the Oxford Department of Physics and its permanent academic staff over the period from 1987 to 2017. Modern émigrés move to new institutions for scientific opportunities and a physicist will typically work in several over the course of their career.
The bright side of the Moon: The historical journey of our tidally locked satellite
Authors: Pumfrey Stephen
Published: November 2024

The paper discusses a major shift in the (Western) science of our Moon. It reconsiders well-known developments, as the Aristotelian concept of distinct celestial and terrestrial worlds in which the Moon was one of seven perfect planetary spheres gave way to our modern view of a very Earth-like body, even endowed at one stage with oceans and continents. It examines the impact of pre-telescopic and telescopic observations in the period 1560 to 1660, notably those of Galileo Galilei and William Gilbert. Its new perspective is to present the strong evidence that supported the idea of the Moon as a planet. In large part this was because it is now known that aspects of the Moon’s orbit are unusual compared with the multiplicity of “moons” in the Solar System. It argues that a major reason was Aristotle’s influential argument for the theoretical impossibility of lunar libration. It concludes with the extraordinary work of William Gilbert (1544-1603) who, it is argued, was the true discoverer of libration because Galileo, who is often credited with it, failed to grasp the necessary dynamics of lunar motion. Notwithstanding, both played crucial roles in the emerging conception of our Moon as “another Earth”. Human activity is now degrading both bodies.
The Apollo Programme and its legacy
Authors: Crawford Ian
Published: November 2024

It is now over fifty years since the Apollo missions to the Moon. This paper briefly reviews the Apollo programme and its scientific legacy, and argues that science would benefit from a human return to the Moon.
The quest for Dark Matter
Authors: Bertone Gianfranco
Published: November 2024

This paper briefly presents the dark matter problem and the many ongoing attempts to solve it. After a brief introduction to the history of dark matter, the paper reviews the relevance of this mysterious component of the Universe in modern cosmology and it discusses the implications of the absence of evidence for dark matter in all experiments carried out in the past four decades. It then argues that a new era has started in the search for dark matter with much astronomical data about to become available and a new generation of gravitational wave experiments about to start operations. Finally, it stresses that the field of dark matter searches is completely open and that there are exciting opportunities for the next generation of scientists to develop new ideas and to make ground-breaking discoveries.
Philosophical questions about the arrow of time
Authors: Deng Natalja
Published: November 2024

Philosophical questioning about the arrow of time is an active research area, but one with a long and industrious history in both physics and philosophy. This paper begins by distinguishing between a puzzle about the origin of the thermodynamic time asymmetry and questions about whether the thermodynamic time asymmetry can itself explain other temporal asymmetries. It goes on to give a brief description of how the puzzle arises in classical mechanics, followed by an interlude on whether and how quantum mechanics might change the situation. Finally, it takes a closer look at the puzzle in terms of statistical mechanics and one proposed solution.
A very brief history of colour metaphysics
Authors: Müller Olaf
Published: November 2024

These are five playfully pessimistic meditations on the metaphysics of colour, arguing that metaphysical thinking does not fit well with the beautiful universe of colours: Neither Platonism nor relativism nor reductionism nor the distinction between primary and secondary qualities nor the denial of the existence of some colours at the expense of others offers convincing ways of dealing with the phenomena of colour. In the final, sixth meditation the standard analysis of magenta is challenged with some unorthodox ideas that can be traced back to Johann Wolfgang von Goethe’s colour research.
Seeing the light: key inventions that illuminate our world
Authors: O’Neill William
Published: November 2024

In the vast expanse of the electromagnetic spectrum the role of light has been paramount in shaping human civilisation as its applications extend beyond mere illumination. This paper delves into the profound influence of light-based technologies on society, culture and various scientific fields by exploring the understanding of the electromagnetic spectrum and highlighting seminal inventions developed from our understanding of it. Historically the visible spectrum served as humanity’s primary interface with light, giving rise to basic tools like the magnifying glass and the prism. However, the 19th and 20th centuries heralded groundbreaking revelations about the broader spectrum—discovering rays invisible to the naked eye from gamma rays to radio waves. This understanding stimulated technological revolutions, profoundly altering our daily lives and global infrastructures. Prominent inventions such as the radio, televison, X-ray machines, optical fibres and lasers, each harnessing distinct parts of the spectrum, have propelled advancements in communication, medicine, materials and information technology. Additionally light technologies have been pivotal in critical breakthroughs in quantum mechanics, relativity and astrophysics, deepening our understanding of the Universe. Light-based technologies rooted in our evolving comprehension of the electromagnetic spectrum have indelibly impacted our world. From fundamentally altering industries to reshaping daily rituals the influence of light is a testament to humanity’s enduring quest for progress and understanding.
The evolution of the atom
Authors: Atkins Peter
Published: November 2024

An informal history of the concept of the atom is described from its earliest inception to the current quantum mechanical model.
Numerical Investigation of the transient process of direct collision between two droplets
Authors: Liu C C
Published: November 2024

The use of spray systems finds widespread applications in fields such as national defense and industry. These systems are employed for spray cooling, spray forming, spray coating, and inkjet painting. Within spray systems, atomized droplets play a crucial role, either impacting surfaces or colliding with each other. Understanding the impact process of these droplets is essential for optimizing spray system performance. In this study, computational simulations focus on direct collision of two droplets. Numerical methods are employed, including structured single-block and staggered grid systems for discretizing the spatial domain. The finite volume method iteratively solves the governing equations of mass and momentum. The coupling between velocities and pressure is handled using SIMPLER methods. During droplet collision, phenomena like deformation, breakup, and merging occur at the boundary. To accurately capture these movements, a level set function approach is utilized. Numerical simulations of a water droplet impinging on a flat surface are compared with experimental results for verification. When two droplets collide head-on with the same Reynolds number and Weber number, they merge into a single oscillating droplet at a fixed position. Increasing the Reynolds number of the two colliding droplets intensifies the oscillation phenomenon in the merged droplet. Even when two droplets collide at an angle or have different sizes, they still merge into a single oscillating droplet. The merged droplet moves in a direction where the original two droplets’ momentum cannot be fully offset.
A revolutionary approach to automate labelling of CAD files
Authors: Chen T C , Chang T H , Lee J C
Published: November 2024

This innovation represents a significant advancement in enhancing processing efficiency when dealing with engineering drawings. Traditionally, the review of customer drawings needs to be executed by experienced experts before manufacture. The identification and labelling of key features were reliant on human intervention for subsequent Design for Manufacturability (DFM) or G-code programming. However, the previous method not only consumed valuable time but also introduced the potential for human errors. In this context, we introduce a high-efficiency technology for recognizing engineering drawings, automatically labelling key features, and converting unstructured data into structured data. It is noteworthy that this technology distinguishes itself from traditional methods, such as R-CNN or similar neural network approaches and differs from pre-labeled engineering drawings reliant on experts manually inputting keywords for dimensions or layers. This work is a vital step towards the realization of intelligent manufacturing. For instance, our customers can now review engineering drawings online and receive immediate feedback. This online interaction is facilitated by processing structured data, a direct output of this presented technology, with other specific modules. Furthermore, the structured data seamlessly integrates into subsequent manufacturing procedures, including notifying the supply chain, generating 3D drawings, and CNC programming. In conclusion, this technology showcases its significance in advancing our vision of intelligent manufacturing at ZY Corp.
An efficient face and mask detection by embedded device via thermal imaging camera
Authors: Wu R C , Xu H W , Wang S Y
Published: November 2024

Since 87.9% of COVID-19 patients develop a fever symptom, the mandatory wearing of masks, temperature screening, and isolation of individuals with fever are the most import methods for community epidemic prevention. This study develops a thermal imaging thermometer embedded system with face, face mask, and temperature detection capabilities using low-end CPU devices. The hardware includes a Raspberry Pi 4, FLIR Lepton 3.5 LWIR Micro Thermal Camera Module, display screen, and alarm. The system is characterized by its low cost and lightweight design, and it only needs to detect necessary areas around the face area during face mask and temperature detection, effectively avoiding external interference and further enhancing the effectiveness of epidemic prevention. The face detection model is based on the YOLO-Fastest architecture and has been improved, referred to as Pi-fast. In terms of performance on the training and testing sets, our proposed Pi-fast achieves Mean Average Precision (mAP) values of 99.64% and 93.18%, F1 score values of 0.94 and 0.87, and Intersection over Union (IoU)values of 78.07% and 65.98%, respectively. Regarding system performance, the frame rate of FLIR Lepton 3.5 Thermal Camera Module hardware specifications is 8.7 FPS. When using YOLO-Fastest and proposed Pi-fast model for detection on the proposed thermal imaging system, the frame rates are 6.58 FPS and 7.32FPS, respectively. The proposed Pi-fast model outperforms YOLO-Fastest about 0.74 FPS (11.2%). The system can detect objects at a distance of about 7 meters from the lens in thermographic camera with a resolution of only 160×120 pixels, making it suitable for multi-person screening and improving the screening process’s efficiency. The system can effectively perform temperature screening and face mask detection, making it suitable for office buildings, schools, medical clinics, and other public areas. During the severe epidemic period, the proposed thermal imaging embedded system that was actually used for epidemic prevention work at I-Shou University, improving screening efficiency and reducing labour costs.
Thread plate posture analysis for screw rolling adjustment design
Authors: Wen C C , Chang C T , Yang T D
Published: November 2024

This research focuses on process design of the adjustment of movable thread plate and fixed thread plate in the screw rolling machine during production. By observing some key dimensions of the threaded screw, one can determine the movement amount and the rotation direction of the adjustment screw bars mechanism of the fixed thread plate that required for the specified size of this type of screw. One establishes a relationship from the adjustment of the screw bars mechanism to the fixed thread plate posture. It can be seen that the formed screw size deviations will lead the machine operator to adopt one of the proposed process to achieve the posture adjustment of the fixed thread plate. While the screw specification deviations do not conform to the standard ones, the operator just need to find out the error type of the formed screw and measures its specification to follow one of the proposed formulas, then the wrong thread plate posture can be modified to the correct posture under operator’s adjustment. The method addressed in this research can not only reduce the operational difficulty of screw thread rolling machine but also can reduce the trial-and-error processes in traditional operation methods.
Numerical study on machining of Al/SiC composite materials
Authors: Fann K J , Lu Y T
Published: November 2024

Metal matrix composites (MMCs) comprising aluminum (Al) matrices reinforced with silicon carbide (SiC) particles have garnered significant attention in recent years due to their outstanding specific strength, stiffness, corrosion resistance, and thermal conductivity. However, to achieve the desired geometry and shape of such MMC workpiece, a cutting process is still necessary, which involves a complex phenomenon of mechanical interactions that can result in surface defects and reduced tool life. This study aims to numerically investigate the cutting process of Al/SiC MMC workpieces in a manner that closely resembles reality by developing a finite element model directly from a metallographic image of a composite with a 30% volume fraction of 10 μm SiC grit. The research focuses on the effects of cutting depth, cutter rake, and the interaction between the cutting tool and the SiC particles. The results demonstrate that, depending on the contact point with the SiC particle, there is a variation in the cutting force generated when the cutter tip encounters the SiC particle. This causes the particle to break, rotate, roll over the matrix, and embed deeper into the matrix. Furthermore, based on the analysis of variance applied to the cutting force, the cutting depth exhibits a significant influence, while the cutter rake shows no significant effect on the cutting force.
ANCF-based modelling of rigid-flexible coupling of helicopter flexible rotor blades
Authors: Mei Xiaohan , Gu Haiyu , Wei Cheng
Published: November 2024

A high-precision rotor structure dynamic model applicable to a variety of helicopter blade hub structures is established considering rotor blade flexible deformation. The absolute nodal coordinate method is applied to the traditional rotor blade rigid-flexible coupling dynamics model, making the new model applicable to both fully articulated rotor blades and other advanced blade hub structures. No small-volume assumptions were made in the modelling process. Both Green’s strain expression under finite deformation and the geometrical relation of elastic deformation motion based on the absolute nodal coordinate method are used to derive the blade strain energy, kinetic energy, and the external load virtual work. The rotation angle at the articulation constraint at the root of the blade coupled with the elastic deformation degrees of freedom of the blade in three independent rigid body degrees of freedom, respectively. The rotor blade rigid-flexible coupling dynamics equations were established according to the Hamilton action principle. The time-domain simulation is carried out under a free single pendulum and fixed rotational speed/fixed torque for the established flexible blade model, which verifies the validity and high accuracy of the rigid-flexible coupling articulation model of the flexible rotor blade and the blade hub.
Conceptual design and optimization of a hydrogen-powered aircraft with a dorsal tank layout
Authors: Guo Yuan , Chow Jun , Chen Hao , Qiao Xiaotao , Fan Chuning
Published: November 2024

The application of hydrogen as a clean energy source is revolutionizing the aerospace industry, especially in the design and optimization of next-generation aircraft. In this study, a tubular-wing hydrogen-powered aircraft is designed based on a modified Boeing 737 configuration with a dorsal fuselage tank layout. During the design process, the fuselage was parametrically reconstructed to accommodate tanks of different sizes; Subsequently, a multidisciplinary optimization of the hydrogen aircraft was carried out with fuel consumption as the optimization objective. During the optimization process, dynamic mission profiles were introduced to make the fuel consumption calculation more accurate. Finally, this paper compares and analyzes the differences between kerosene-powered and hydrogen-powered aircraft. The results show that the hydrogen airplane has an increase in weight of about 10% and a decrease in lift-to-drag ratio of 1 to 2 units. To offset these effects, a hydrogen airplane would need to be designed with a larger aspect ratio and provide more thrust during flight. Nonetheless, the results also show that, because of the high calorific value of liquid hydrogen, the total energy consumption of the designed hydrogen aircraft is lower than that of a kerosene aircraft for the same range.
Research on evaluation technology for fuel tank inerting system based on task profile
Authors: Wang Zhaoruijia
Published: November 2024

The flammable and explosive characteristics of aviation fuel have always made the safety of aircraft fuel tanks a focus of attention in the aviation industry. At present, all aircraft test flights in our country require the completion of the evaluation of the fuel tank inerting subsystem, which has put forward clear requirements for the measurement of oxygen concentration in aircraft fuel tanks, and corresponding technical indicators have been developed based on the usage of civil and military aircraft. This article establishes a digital model of the aircraft fuel tank inerting system based on AMEsim software, verifies the accuracy of the model through literature data, and uses the digital model to study the variation law of oxygen concentration in the fuel tank. The temporal variation of oxygen concentration in the gas-phase space of aircraft fuel tanks is analyzed under different nitrogen-rich gas concentrations, nitrogen-rich gas flow rates, fuel tank loading rates, and aircraft descent rates. Based on the temporal variation of oxygen concentration, a reference is provided for formulating flight test methods.
Research on identification and quantification methods for loss sources of compressors
Authors: Liu Liangye , Yi Weilin
Published: November 2024

A deep understanding of the internal loss mechanisms and specific values of turbomachinery is crucial for its design and analysis. In this paper, based on the theory of entropy production, the loss sources in the NASA Rotor67 transonic fan and Radiver centrifugal compressor were quantified by using numerical simulation methods and physical flow characteristic description methods. The proportion of losses in various regions was presented. The results show that in the transonic fan, boundary layer losses and wake losses account for more than 70%, while direct shock losses account for less than 2%. Additionally, as the mass flow increases, the losses gradually move downstream, with the proportion of wake losses increasing. Within the wake losses, the influence of tip leakage flow and corner separation flow exceeds 70%. In the centrifugal compressor, as the mass flow decreases, the proportion of impeller losses to the total stage losses increases significantly, from 21.7% at the choking condition to 63.5% near the design condition. Most of the losses within the impeller occur near the casing area, accounting for about 47% of the impeller losses. The areas near the blades and the main flow area are the other two major sources of impeller losses, with both contributing to 36% of the losses.
Traveling wave vibration characteristics of rotating FGM conical shell
Authors: Zhao Changying , Sun Shupeng , Tartibu Lagouge , Han Hesheng
Published: November 2024

Conical shell is common structural component in various rotating machinery. The study of traveling wave vibration performance of conical shell is of great significant for the design of rotating machinery. This paper addresses the traveling wave vibration performance of rotating functionally graded material (FGM) conical shells. Artificial springs, uniformly distributed, are employed to simulate the boundary constraints of rotating FGM conical shell. Accounting for the effects of Coriolis and centrifugal forces caused by rotation, the energy equation of rotating FGM conical shell is calculated, and then the dynamical model of the rotating FGM conical shell under elastic supported constraints is established using the Lagrange equation. The influence of key factors on traveling wave frequency and response characteristics of rotating FGM conical shell are investigated including rotational speed, half-cone angle and material components.
Periodic orbits of solar sails in the Sun-Earth system
Authors: Liu Lei , Zhang Xin
Published: November 2024

This paper studies the periodic orbits of solar sails using reflectivity control devices (RCDs) in the circular Sun-Earth system. Significantly, the dynamical equations about the solar sail are given separately in the rotational coordinate system and adjoint coordinate system. Analytical solutions about the periodic orbits of solar sails are given. So as to gain the periodic orbits of solar sails, we discuss the conditions of the attitude angles and reflectivity modulation ratio of solar sails. This paper simulates some periodic orbits of solar sails and analyzes the stability of a periodic orbit of a solar sail by using the Floquet theory. The outcomes show that it is unstable for the periodic orbit of a solar sail. Based on the linear quadratic regulator (LQR), this paper designs a control algorithm to achieve tracking in the target orbit of solar sails.
Numerical simulation of fuselage sliding on calm water for an amphibious aircraft based on global moving mesh method
Authors: Gao Xianjiao , Sang Tengjiao , Li Xu , Qu Rujun , Han Xiaohong
Published: November 2024

Aiming at the large motion fluctuation of fuselage sliding on calm water, a numerical simulation method based on the global moving mesh method is introduced by using the computational fluid dynamics software of STAR-CCM+, the two equations SST k-w turbulence model to solve the RANS equations, the VOF method to capture free surface, the DFBI module to simulate the movement of the fuselage. We established a simulation scheme on the sliding movement of the fuselage on calm water, which effectively solves the problem of calculation divergence caused by the excessive stretching deformation of the mesh. Comparison between calculation results and model test results shows that the trends of resistance and attitude angles changing with velocity are basically the same, and the relative errors are around 10%, which indicates that the global moving mesh method is feasible in the simulation of fuselage sliding on calm water.
Solar sail transfer strategy for long-duration multi-objective mission in cislunar space utilizing solar radiation and reflectivity control device
Authors: He Guanwei , Zhang Binbin , Wu Jun
Published: November 2024

This study delves into the complexities of optimizing solar sail trajectories for long-duration multi-objective missions in cislunar space, focusing on orbital transfers between halo orbits and distant retrograde orbits. It presents an innovative transfer strategy that integrates solar radiation propulsion and reflectivity control devices to effectively adjust thrust force magnitude and direction, thereby improving maneuver capabilities. The optimization method is founded on the coupled dynamics of a solar sail, aiming to minimize the transfer time of flight using the Hermite-Simpson collocation method while ensuring optimal performance. Through thorough analysis and comparison, the research strives to determine the most efficient trajectory for solar sail orbital transfers in cislunar space.
Stability analysis of micro-probe landings in complex terrain
Authors: Cheng Zhen , Zhang Yuanxun , Qing Wushi , Zhang Baogui
Published: November 2024

Addressing the problem of landing stability of the micro-probes on the surface of extraterrestrial objects, combined with the geometric properties of the orthotetrahedron, this paper proposes a structural design method of the four-spine microprobe landing bracket that can adapt to the complex terrain and carries out the analysis of the landing stability of the four-spine bracket under the state of three-legged landing and the optimization of the structure for combined terrain of stones and slopes. Referring to the ZMP theory, the harsh working conditions of the four-spine bracket when landing are sorted out and determined. Based on the kinematics theory, the collision mechanism between the four-spine bracket and the ground is analyzed, and a landing model suitable for the micro-probes is established, which provides the basis for determining the landing stability of the micro-probe. Around the collision mechanism and landing model, the dimension optimization of the four-spine bracket is carried out, and the results of Adams dynamics simulation analysis and prototype test show that the landing stability of the four-spine bracket is improved, which verifies the validity of the optimization idea.
Characterizing the contact force of a high-speed rotating fluid on brush wire
Authors: Li Tian , Wu Jiang , Zhong Jiangying , Guo Zhijun , Fu You
Published: November 2024

To study the effect of coolant fluid on rotor-brush wire contact in high-speed conductive slip rings, the rotor-brush wire contact model is simplified to two cylindrical vertical contacts. The theoretical formula of the force on the near-wall surface of the brush wire is derived by combining the distribution of the characteristics of the cylindrical rotating fluid domain. A three-dimensional model of high-speed rotor-brush wire fluid-solid coupling is created. The initial preload and coolant disturbance on the near-wall surface of the brush wire is considered to analyze the force characteristics of the brush wire. The force characteristics of the near-wall surface and the three-dimensional surface velocity cloud diagram of the fluid domain are obtained. The results show that the growth rate of the fluid domain force on the wall surface of the brush wire increases with the increase of rotational speed. A change of only 0.5 mm near the wall leads to a change of nearly 40% in the speed.
Analysis of the effects of combined suction on hypersonic inlet starting performance
Authors: Peng Siyi , Xu Shangcheng , Wang Yi
Published: November 2024

Taking a two-dimensional inlet (Case 1) as the original inlet, the combined suction schemes are designed and their influences on the self-starting ability of the inlet are studied. The flow fields at the design point and the self-starting progress of the inlets are calculated by the numerical simulation method. The results show that the three-slot combination scheme (Case 2) leads to the reduction of the mass flow rate of the throat at the design point by 1.15% and the increase of the total pressure recovery coefficient by 6.73%. The self-starting Mach number of the inlet decreases from 4.6 to 3.2, which indicates that the self-starting ability is improved significantly by the three-slot combination scheme.

In order to illustrate the role of each slot in improving the self-starting ability, three two-slot combination schemes, which are called Case 3, Case 4, and Case 5, are set up by closing Slot 1, Slot 2, and Slot 3 in turn and their self-starting processes are simulated. The results indicate that the self-starting Mach numbers of Case 3, Case 4, and Case 5 are 3.6, 4.1, and 4.5 respectively, which are 0.4, 0.9, and 1.3 higher than that of Case 2 respectively. Slot 3 has the greatest influence on the self-starting ability. When the incoming Mach number rises to 4.2, a closed separation zone is induced between Slot 2 and the throat by the reflected shock wave on the cowl side of Case 5. Due to the lack of lip overflow, which is an important flow regulation mechanism, the separation zone has a strong self-sustaining ability, and the inlet keeps unstart until the incoming Mach number rises to 4.5. In addition, in the absence of Slot 1 or Slot 2, the large-scale separation zone will not disappear until the incoming flow pressure increases to a certain value.
Fluid-thermally-solid coupling analysis of aircraft leading edge
Authors: Kang Xiaozhi , Du Lin , Shi Qinchuan , Wang Xiaoyu
Published: November 2024

Aircraft are affected by aerodynamic loads during operation. To analyze the impact of the leading edge structure of aircraft under different flight angles of attack, this paper uses the fluid-heat-solid coupling calculation method. It combines CFD with the thermal-structure field solver and uses simulation software, with a flight altitude of 15 km, flight speed of 6 Ma, and flight Angle of attack of 0 ~ 20°. Considering the change of material parameters with temperature, the coupling of multiple physical fields in aircraft is simulated and analyzed. The simulation results show that the existence of the flight angle of attack makes the flow field shock wave position of the aircraft closer to the windward surface of the structure. The angle of attack exacerbates the structural deformation of the aircraft, with the maximum deformation occurring at a 20° angle of attack, which is 3.06 mm. The research results can provide a reference for aircraft design.
Effects of Sulfuric Acid-Water Immersion on the Properties of Ethylene Propylene Diene Monomer, Thermoplastic Vulcanizates, and Eco-Friendly Thermoplastic Vulcanizates
Authors: Foltuț Daniel , Pospisil Jan , Pascal Dragoș-Toader
Published: November 2024

This research investigates the impact of sulfuric acid-water solutions on the physico-chemical characteristics of ethylene propylene diene monomer rubber (EPDM), thermoplastic vulcanizates (TPV), and ECO TPV materials. We evaluated the deterioration of these materials by subjecting them to acidic environments and using methods such as differential scanning calorimetry (DSC), volume and weight measurements, hardness measures, and scanning electron microscopy (SEM). The samples were submerged in solutions of H2SO4 with concentrations of 1M, 0.1M, and 0.001M at a temperature of 90°C for a duration of 1000 h. The results indicated that EPDM had superior chemical and thermal stability, accompanied by negligible changes in weight and volume. The TPV exhibited moderate stability, however the ECO TPV showed severe deterioration, as seen by major increases in weight and volume, as well as notable changes in DSC profiles. Surface degradation and cracking, especially in ECO TPV samples, were observed using SEM investigation. The hardness results indicated little changes in hardness after exposure to the various chemical aging techniques. The results indicate that EPDM and TPV are better suited for use in acidic conditions, such as fuel-cell systems. However, ECO TPV may need extra stabilization in order to enhance its endurance.
Parliamentary dimension of the Council presidency: Testing a research framework through the case of the 2016 Dutch rotating presidency of the EU
Authors: Nováková Tereza
Published: November 2024

Measuring the level of parliamentary involvement in European Union (EU) affairs cannot be undertaken without any reference to the parliamentary dimension, an integral part of the 6-month rotating presidency of member states in the EU. The parliamentary dimension encompasses all activities performed by the presidency parliament, playing a crucial role in shaping EU decision-making processes. Although a recently published study by Kaniok and Nováková has addressed for the first time the theoretical groundwork for studying this phenomenon, their proposed research framework has not yet been applied to a specific case. This study addresses this gap by applying the framework to the Dutch presidency of the Council of the EU in 2016, evaluating its effectiveness, and refining it to ensure broader applicability. By doing so, it not only validates the framework but also enhances its potential for enabling comparisons of national parliaments across presidencies, facilitating the exchange of best practices, and developing a typology of national parliaments’ roles in the EU presidency.
Correction of Microtia with Constricted Ear Features Using Helix Costal Cartilage Scaffold and Postauricular Flap Advancement
Authors: Wang Chenglong , Gao Dejin , Luo Pan , Wang Yue , Zhang Qingguo
Published: November 2024

Background:

Microtia with constricted ear features represents a challenging congenital deformity characterized by the variable shape and large volume of the remnant cartilage and skin involved. This study aims to evaluate the efficacy and safety of a method using helix costal cartilage scaffold and postauricular flap advancement for the correction.

Methods:

This retrospective study analyzed the clinical and postoperative data of 121 patients diagnosed with microtia and constricted ear features, treated at our institution between January 2020 and January 2023. All patients underwent helix reconstruction using the eighth or ninth costal cartilage combined with postauricular flap advancement. Outcomes were assessed based on the incidence of postoperative complications and auricular aesthetic scores. The aesthetic evaluation of the reshaped auricle was based on a four-point Likert scale (i.e. 1 = poor, 2 = fair, 3 = good, 4 = excellent).

Results:

The postoperative follow-up period ranged from 12 months to 3 years (mean 18.5 months). All patients achieved successful helix expansion, with reconstructed ears showing improved symmetry and shape comparable to the contralateral normal ears. The average aesthetic score was 3.4 out of 4. Complications included suture exposure in 8.3% of cases and cartilage protrusion in 4.1%, both managed without significant issues. There were no instances of skin necrosis, costal cartilage exposure, or infection.

Conclusions:

The combination of helix costal cartilage scaffold and postauricular advancing flap offers a reliable and effective method for correcting microtia with constricted ear features, providing satisfactory aesthetic outcomes with minimal complications.
The Persistence of Biologic Therapies for Psoriatic Arthritis
Authors: Jasmen Magdalena , García Dominga , Ibáñez Sebastián , Díaz Pamela
Published: November 2024

Drug persistence is a crucial measure of long-term efficacy, safety, and patient satisfaction. Lack of persistence can increase healthcare costs and morbidity and mortality rates. This review aimed to consolidate available data on drug persistence for various biological treatments used as the primary intervention for psoriatic arthritis and identify factors associated with nonpersistence. Reports indicate variable 1-year persistence rates for biologic therapies, ranging from 37% to 73%. Specifically, tumor necrosis factor inhibitors have shown fluctuating 1-year persistence rates ranging from 32% to 85%. IL-12/23 and IL-23 inhibitors demonstrate persistence rates of 25% to 89%, whereas data for IL-17 and JAK inhibitors are more limited, ranging from 51% to 77%. Factors such as female sex and a higher burden of comorbidities have been associated with an increased risk of nonpersistence, although evidence regarding other factors remains scarce. The significant variability in reported persistence rates may be attributed to differences in treatment gaps and methodologies across studies. Addressing and mitigating the factors leading to nonpersistence is essential for improving treatment outcomes in psoriatic arthritis.
Diversity pattern and antibiotic activity of microbial communities inhabiting a karst cave from Costa Rica
Authors: Vásquez-Castro Felipe , Wicki-Emmenegger Daniela , Fuentes-Schweizer Paola , Nassar-Míguez Layla , Rojas-Gätjens Diego , Rojas-Jimenez Keilor , Chavarría Max
Published: November 2024

The studies of cave bacterial communities worldwide have revealed their potential to produce antibiotic molecules. In Costa Rica, ~400 caves have been identified; however, their microbial diversity and biotechnological potential remain unexplored. In this work, we studied the chemical composition and microbial diversity of a Costa Rican cave (known as the Amblipigida cave) located in Puntarenas, Costa Rica. Additionally, through culture-dependent methods, we evaluated the potential of its microbiota to produce antibiotic molecules. Mineralogical and elemental analyses revealed that the Amblipigida cave is primarily composed of calcite. However, small variations in chemical composition were observed as a result of specific conditions, such as light flashes or the input of organic matter. The 16S rRNA gene metabarcoding revealed an extraordinarily high microbial diversity (with an average Shannon index of ~6.5), primarily comprising bacteria from the phyla Pseudomonadota, Actinomycetota, Firmicutes and Acidobacteriota, with the family Pseudomonadaceae being the most abundant. A total of 93 bacteria were isolated, of which 15% exhibited antibiotic activity against at least one Gram-positive or yeast strain and were classified within the genera Lysobacter, Streptomyces, Pseudomonas, Brevundimonas and Bacillus. These findings underscore the highly diverse nature of cave microbiota and their significant biotechnological potential, particularly in the production of antibiotic compounds.
Wastewater sequencing from a rural community enables identification of widespread adaptive mutations in a SARS-CoV-2 Alpha variant
Authors: Conway Michael J. , Novay Michael P. , Pusch Carson M. , Ward Avery S. , Abel Jackson D. , Williams Maggie R. , Uzarski Rebecca L. , Alm Elizabeth W.
Published: November 2024

Background

Central Michigan University (CMU) participated in a state-wide wastewater monitoring program starting in 2021. One rural site consistently produced higher concentrations of SARS-CoV-2 genome copies. Samples from this site were sequenced retrospectively and exclusively contained a derivative of Alpha variant lineage B.1.1.7 that shed from the same site for 20-28 months.

Results

Complete reconstruction of each SARS-CoV-2 open reading frame (ORF) and alignment to an early B.1.1.7 clinical isolate identified novel mutations that were selected in non-structural (nsp1, nsp2, nsp3, nsp4, nsp5/3CLpro, nsp6, RdRp, nsp15, nsp16, ORF3a, ORF6, ORF7a, and ORF7b) and structural genes (Spike, M, and N). These were rare mutations that have not accumulated in clinical samples worldwide. Mutational analysis revealed divergence from the reference Alpha variant lineage sequence over time. We present each of the mutations on available structural models and discuss the potential role of these mutations during a chronic infection.

Conclusions

This study further supports that small wastewater treatment plants can enhance resolution of rare events and facilitate reconstruction of viral genomes due to the relative lack of contaminating sequences and identifies mutations that may be associated with chronic infections.