bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of aluminium alloys’ formability by elevated temperature testing
Authors: Ali M S , Chen W L , Hsuan H , Yang Y L
Published: November 2024

This work presents an investigation of the warm formability of AA7075-T6 aluminium alloy sheets using both experimental and numerical methods. Forming limit diagrams (FLDs) can be created by plotting the failure criteria on a graph with two axes representing major and minor strains. Sheets with a grid can be used to quantify both large and minor strains. General techniques available for the grid involve regular patterns of circles in this experiment. Experiments were conducted at various temperature levels, including room temperature, 100, 120, 140, 160, and 180 °C, as well as different strain rates. The investigation has revealed a significant impact of temperature on formability, while the effect of forming speed is quite insignificant across the whole range studied. At an ageing temperature of 140 °C, the distribution of precipitates is evenly balanced, resulting in improved mechanical strength. To offer accurate numerical models for warm-forming processes, a proposed constitutive model is introduced for aluminium alloy sheets. The present model incorporates plastic anisotropy and the effects of temperature and strain rate dependence. An investigation was conducted on the stress-strain behaviour of thin sheets composed of AA7075-T6 aluminium alloy under elevated temperatures and different strain rates. The objective was to ascertain the appropriate fitting parameters. It was associated with ABAQUS finite element modelling. The recommended material model was utilized to build finite element models, which were subsequently compared to the experimental data. The findings obtained from simulated isothermal uniaxial tensile tests were compared to the empirical measurements. The models used in the tensile test accurately predicted the material’s mechanical response. The predicted failure location, punch forces, and strain distributions for all three forming processes were found to be in close agreement with the experimental results. During deep draw operation, the warm forming limit curves were utilized to precisely predict both the pierce depth at which failure occurs and the precise location where the failure initiates.
Determination of process parameters for additive manufacturing with Inconel 718 powder
Authors: Lee J N , Chen T H , Shie M J , Ye Z L
Published: November 2024

In this study, the additive manufacturing (AM) of Inconel 718 was investigated, and the processing parameters can affect the mechanical properties of the product. The five-axis laser cladding composite processing machine Tongtai AMH-630 is used, and the laser power is set to 800W based on the thermal impact of the laser on the base plate. However, the laser scanning speed (600-1200mm/min) and powder feed rate (3~15g/min) are not arbitrary combinations. It is recommended to present the feed per unit length in g/mm, which seems to be more clearly expressed. Regardless of changes in laser scanning speed and wheel speed, it is a reasonable decision to control the combination of the two at about 0.01-0.013g/mm. Through single-pass cladding experiments, we select different combinations of laser scanning speed and powder feed rate with a cladding aspect ratio in the range of 3:1 to 4:1. In the multi-pass cladding experiment, an overlap rate of 30% was used as the plane cladding spacing; a spacing of 80% of the cladding height was used as the stacking height. This study uses scanning speeds of 600, 700, 800, 1000 and 1200mm/min to clad a rectangular body. Tensile test specimens were processed using a CNC lathe, and tensile tests were conducted to obtain variations in tensile strength and elongation at different scanning speeds. The mechanical properties of both will decrease as the scanning speed increases. At a scanning speed of 600mm/min, its tensile strength is comparable to that of Inconel 718 standard materials; but its elongation is 61% of that of standard materials. If Hot Isostatic Pressing (HIP) is applied after cladding, it seems that a higher scanning speed can achieve a performance closer to that of standard materials.
Integrating machine vision in the development of automatic mounting system for massive electroplating components
Authors: Lee C H , Huang P H , Ye J W
Published: November 2024

The traditional industrial electroplating parts manufacturing process typically relies on manual labour to suspend them in the electroplating tank, requiring a significant amount of manual work. However, due to a shortage of manpower and frequent staff turnover, this has posed challenges to production efficiency. Therefore, this research proposes an automated mounting system by integrating machine vision technology and the development of robotic arms to replace the conventional manual suspension method. The automated mounting system initially separates individual ring-shaped electroplating components using a disk vibratory feeder. Subsequently, it utilizes a unidirectional reciprocating mechanism and infrared detection to position these electroplating components onto a backlit panel. Then, the IDS uEye XS2 autofocus camera captures images, and in conjunction with machine vision technology, rapidly determines the position, characteristics, and orientation of these ring components. Finally, through TCP communication protocol, commands for gripping points are transmitted to the robotic arm, which uses electromagnetic valves on the arm to pick up the components and suspend them onto the hanger using an optimized path. The final test results demonstrate that the automated installation system can complete 14 installation operations per minute, effectively reducing the time and cost associated with manual labour, significantly enhancing the production output of the assembly line. Therefore, this study combines machine vision technology to propose a solution for the automated installation system of large-scale electroplating components.
Effect of sodium tungstate concentration on surface morphology and hardness variation of 6063 aluminium alloy using by plasma electrolytic oxidation
Authors: Chen H L , Lu T H , Lin W C , Chiu S X
Published: November 2024

The coatings were prepared on the surface of 6063 aluminium alloy using by plasma electrolytic oxidation in a sodium tungstate (Na2WO4) electrolyte solution with concentration varying from 0.017 to 0.068 mol/L. The power of plasma electrolytic oxidation is about 600 W, electrolysis time is 20 and 30 minutes, respectively. In this study using sodium tungstate as the main component of the electrolyte without any additives. The effects of Na2WO4 concentrations on the surface morphology and hardness variation of the 6063 aluminium alloys are investigated. These oxide films on aluminium were characterized by laser scanning confocal microscope, scanning electron microscopy (SEM) and Vickers microhardness indenter (Hv), respectively. The results reveal Na2WO4 electrolyte solution with concentration varying from 0.017, 0.034, 0.051 to 0.068 mol/L. When the electrolyte concentration is 0.034 mol/L, the maximum hardness value is 104 Hv after plasma electrolytic oxidation for 20 minutes. When the electrolyte concentration is 0.051 mol/L, the minimum surface roughness value obtained by plasma electrolytic oxidation for 30 minutes is Sa 0.324 μm.
Lateral-directional stability and control augmentation system design for civil aircraft simulator
Authors: Chen Lei , Xie Gangtao
Published: November 2024

In this paper, we first introduce the necessity, history, and classification of stability and control augmentation systems. The structure of the lateral-directional stability and control augmentation control system in the normal mode is studied, and a comparison of advantages and disadvantages of several design schemes including yawing rate feedback, rolling rate feedback, and sideslip angle feedback is given. Lateral-directional stability and control augmentation control law for a certain type of civil aircraft simulator is designed. Finally, the stability and control augmentation system is simulated and the simulation results are analyzed, which shows that the handling qualities of the aircraft with stability and control augmentation system are better than those without it.
Optimization of Composite Wheel Fender for Manned Lunar Vehicle
Authors: Shen Zhenghui , Yin Yulei , Zhang Chongfeng , Li Tao , Fu Hongwen
Published: November 2024

Weight reduction is the eternal theme of aerospace optimization. In the process of weight reduction, the main ways are material change, structural change, and processing method change. In the process of aerospace structure design, the boundary and load conditions are more complicated, which restricts the development of optimization technology in the aerospace field to some extent. At present, the research object of optimization technology in the aerospace field is mainly the large parts of the aerospace craft, and the structural optimization of small aerospace parts is rarely involved. Therefore, the research of structural optimization design method has important theoretical and engineering significance. A complete optimization design process is proposed, the structural performance of aviation products is simulated by finite element software, and the feasibility of the optimization theory is verified. This article mainly compares several schemes for weight reduction design of composite material wheel fenders in the process of design.
Research on machining technology of stepped boring for intersecting holes in aircraft
Authors: Chen Xuezhen , Liu Chun , Song Jinhui , Cheng Cheng , Kang Zhiwen , He Yufan , Tian Changle , Yu Long , Hao Long , Guo Wei , Luo Jiang
Published: November 2024

During the assembly process of a large-scale aircraft fuselage, critical bearing areas require the drilling of intersecting holes, which are commonly processed using traditional single-edged reamers by most domestic manufacturers. To improve the efficiency and accuracy of the finishing process for these holes, enhance the quality of the assembly, and further shorten the construction cycle for precision processing, improvements need to be made to traditional single-edge reamer machining methods. This paper proposes a new approach that uses stepped reamers to machine intersecting holes. By setting up an experimental platform to simulate actual processing conditions and optimize processing parameters, the study analyzes and compares the quality and efficiency of traditional reaming and stepped reaming modes. The results show that stepped reaming can improve processing efficiency by 50.6% compared to traditional machining while also reducing human intervention and minimizing quality risks. The findings from this research project can be extended to various aircraft fuselages or wings for precise drilling of intersecting holes, providing significant guidance for efficient and high-quality delivery of aircraft.
Study on the influence of expansion waves on the reflection type of shock wave in double-wedge configurations
Authors: Wang Liyao , Yang Li , Yue Lianjie
Published: November 2024

This paper investigates how variations in the relative positioning between the expansion fan emitted from the triple point in the shock/shock interference on double-wedge geometries in confined spaces and the incidence point of oblique shocks influence the transition of oblique shock reflection types, and understands the roles of expansion waves in inhibiting MR. Predictive analysis through the shock polar line provides critical values for the transition of oblique shock reflection types under the influence of expansion fan effects. The position where the shock/expansion fan undergoes post-oblique reflection on the opposite sidewall can be controlled by adjusting the model’s contraction ratio (H
1/H
2). This study uses the density-based solver blastFOAM in openFOAM to numerically solve the Euler equations, conducting inviscid calculations of shock/shock interactions induced by double wedges in confined spaces with ideal gases. This study compares pressure values in different regions obtained from numerical simulations and examines the reflection types of oblique shocks on opposite sidewalls, confirming the feasibility of shock polar analysis and the accuracy of theoretical predictions.
Longitudinal SCAS design and simulation for civil aircraft simulator
Authors: Xie Gangtao , Qu Xiaoyu , Chen Lei
Published: November 2024

In this paper, the principle and benefits of stability and control augmentation system (SCAS) are introduced. Four schemes of the longitudinal SCAS for civil aircraft in normal mode are analyzed and compared. One of them, i.e., C * response type, is selected. Its architecture is determined. Then, based on a typical civil aircraft, the flight control law of the longitudinal SCAS is designed. A simulation model of the longitudinal SCAS is established through MATLAB software. Finally, the simulation and verification of the longitudinal SCAS model is carried out. The simulation results show that the designed longitudinal SCAS is feasible and can be applied to engineering practice. Compared with either normal load or pitch rate command response type, with proportional and integral feedback for mixed control signals of pitch rate and normal load, C * not only improves the short period characteristics but also effectively separates phugoid and short period frequencies, thus achieving high control accuracy.
Experiment study on the influence of component separation on civil aircraft ditching
Authors: Luo Wenli , Chen Shuyong , Fang Wei , Chang Liang
Published: November 2024

In order to meet the requirements of airworthiness regulations, research focusing on the influence of component separation on water impact loads during civil aircraft ditching was carried out through a series of scaled aircraft experiments. The engines, flaps and landing gear doors, which may affect impact force and airtightness, were sufficiently considered. The time history of pitch angle, acceleration and pressure distribution were measured and fully compared with the intact aircraft. The results show that different with the separation of flaps and landing gear doors, the breaking of engines will lead to severe impact response due to the increased suction force. The airtightness can be ensured even if the landing gear doors fall off since the impact load on the internal structure is relatively low, but the load on the wing body fairing will increase. Finally, the influence on the total ditching overload is discussed, which indicates that the overload of aircraft with an open engine inlet is the highest of an 8.7% increase.
Flight experimental analysis of largemulti-propeller airtanker dropping capability
Authors: Wang Shifei , Li Zhuopeng , Cheng Zhihang , Zhang Ling
Published: November 2024

In the absence of a dropping capability experiment of domestic airtankers, it is necessary to know the actual dropping capability of fixed-wing airtankers for data support to wildfire-fighting, improving fire-fighting efficiency, and reducing the loss of forest and grassland resources. According to the design characteristics of large multi-launch propeller airtankers in China, this experiment shall collect retardant samplesof the filled flame retardant with collection equipment on the flat ground after being dropped by the airtanker in the air. Then, the sample coverage was counted and contour maps of the ground patterns were plotted to compare the dropping coefficients, dropping heights, and dropping speeds of the different dropping modes. At the last, according to the comparison result, the best dropping strategy shall be shown in different requirements. The result shows that when the coverage level is required to be GPC-6, the maximum coverage shall be obtained by all compartments released simultaneously, with a maximum coverage coefficient of 0.16. When the coverage level is required to be GPC-1, it is better to release the retardant from the tank independently with a suitable interval for larger coverage, and the maximum coverage coefficient is 4.49.
Wind turbine blade health state assessment based on fuzzy evaluation
Authors: Zhang Lixin , Zhou Bo , Wang Suisui , Sun Ning , Zheng Haocheng
Published: November 2024

Due to the health state of wind turbine blade being affected by many factors and the mechanism being unclear, a fuzzy evaluation method using SCADA information is proposed. Firstly, the index structure of blade health state assessment is determined by correlation analysis of SCADA data. Secondly, entropy weight is used to allocate weights to all levels of parameters, and then the index data degradation function is optimized by the 3σ criterion. Thirdly, the ridge distribution function is utilized to establish the membership function of the health indexs. Finally, a mathematical model is created for the fuzzy comprehensive assessment of the blade health status. The described techniques is employed to assess the blade health state in the Qingdao wind farm. The “healthy” and “dangerous” states of the blade can be distinguished. The assessment result aligns with reality, verifying that the method in this paper is applicable to the blade health state assessment of wind farms.
Study on solid powder fuel transport characteristics and mixing degree in scramjet combustor
Authors: Liu Tianwei , Fang Shuzhou
Published: November 2024

The powder scramjet engine is considered the best engine for hypersonic weapons because of its advantages of easy adjustment, flame stability, and high efficiency. However, due to the extremely short residence time of particle fuel in the combustion chamber under high Mach conditions, there is a risk of fuel mixing. Based on the existing combustion chamber models of scramjet engines, this paper proposes a new solid fuel blending enhancement structure by combining shock generator structure and transverse jet and compares the performance and mass transfer characteristics of different shock generators. The CFD method is used to solve the RANS formula to simulate the particle transfer process, and the SST k-ω model is used to calculate the complex turbulence. It was found that when the reverse shock generator was used, the mixing degree of solid particles was higher.
Pressure control and support technology for spacecraft space exploration
Authors: Liu Huahua , Xuan Jianqiang , Meng Yao , Han Yan , Wang Donghui
Published: November 2024

As a top-level requirement for ensuring the exploration work inside and outside the spacecraft, the cabin pressure control technology of the spacecraft ensures the safety of astronauts and is one of the core systems for maintaining astronaut space exploration. This article introduces the pressure control and support technology for space environment exploration and constructs a cabin pressure control model. Through simulation verification, the constructed model meets the requirements of spacecraft cabin pressure control, and can effectively save the extravehicular activity air source. This technology can provide a reference for pressure support systems for manned space stations, Mars, and lunar exploration spacecraft.
Vibration optimization methods of dredger engine room
Authors: Zhang Yong , Li Chengjun , Qiao Guorui , Sun Xuerong , Chen Shumei
Published: November 2024

Due to the large number and heavy weight of equipment, as well as the high center of gravity in the cabin area of dredgers, the concentrated arrangement of equipment is prone to local vibration problems in the cabin area. Additionally, there are many devices that need to be placed under the deck in the cabin area, which imposes significant constraints on the placement of supports. Using the finite element method to analyze the vibration problem of a certain dredger, we studied the influence of different equipment arrangements and structural reinforcement methods on vibration. This allowed us to summarize the characteristics of vibration under different improvement methods, providing feasible solutions for improving the vibration problem in the cabin area of dredgers. After adjusting the equipment layout and reinforcing local structures, the vibration in the dredger’s cabin area ultimately meets the design requirements satisfactorily.
Study on the energy absorption characteristics of multi-spherical point-contact cushioning components
Authors: Sun Xiaoting , Wang Yi , Zhu Xiujie , Che Jinli , Wang Wei
Published: November 2024

Under the impact load, the weak parts in the structure are prone to damage, leading to the failure of the whole equipment to work properly. Selecting appropriate cushioning materials to resist impact is a commonly used technical method. Generally, the cushioning efficiency of cushioning materials is proportional to their thickness. For structures with unlimited space, the impact resistance can be improved by increasing the thickness of cushioning materials. However, for structures with limited space, ductile metals are generally selected as cushioning materials to absorb energy through plastic deformation. In this paper, a cushioning component with a multi-spherical point contact structure is designed and processed with ductile metal. Energy absorption properties of the structure under the same impact load with different spherical diameters and numbers are studied based on the Split Hopkinson Pressure Bar (SHPB) test. The test results show that under the same impact load, the larger the spherical diameter is, the smaller the impact deformation is. Energy absorption efficiency is proportional to the number and diameter of the spheres. The maximum energy absorption of the 4×Sϕ6 spherical structure is 26.6J, with an energy absorption rate of 37.3%. The research results provide guidance for the design of cushioning components under impact load.
Dynamic radar cross section similarity study based on dynamic time warping
Authors: Chen Yujiao , Pei Binbin , Zhang Jiuxing , Xu Haojun , Wang Chaozhe
Published: November 2024

Dynamic radar cross-section (RCS) represents the radar reflectance cross-section of an aircraft at different moments during flight and is a crucial criterion for evaluating the ability of a radar to detect an aircraft. In practice, it is challenging to construct an accurate 6-DOF dynamics model for the purpose of solving its dynamic RCS. Consequently, a 3-DOF dynamics model is employed for the analysis of dynamic RCS. This paper presents a methodology for the joint simulation of the dynamic RCS under two DOF models and subsequent comparison and analysis of the resulting sequence data via the dynamic time warping algorithm. It is also concluded that the dynamic RCS values calculated using the 3-DOF dynamics model can identify the target vehicle.
Dynamics modeling and simulation for satellites with optoelectronic tracking system
Authors: Si Zhuhua , Ren Bin , Lyu Gaojian , Xue Chao
Published: November 2024

The optoelectronic tracking system has a strong coupling between the tracking platform and the satellite platform when rapidly capturing and precisely tracking targets. The high-precision coordinated pointing control between the two platforms is a key technology in the fields of space laser communication, debris monitoring, and astronomical observation. Firstly, a multi-level coupled dynamics model of spacecraft with two-dimensional (2D) motion platforms is derived based on the principles of momentum and angular momentum. Secondly, the coupling effects between the motion platform and the satellite platform are theoretically analyzed, highlighting the impact of platform orientation, configuration, mass properties, and motion characteristics on the coupling. Finally, a multi-level platform cooperative control strategy is proposed, and the model and control strategy are validated through mathematical simulations. The results show that the model is consistent with simulation results from ADAMS software, and the satellite attitude accuracy under the cooperative control strategy can be improved by 80%.
Numerical simulation of jet interaction flow field of complex configuration based on hybrid grid method
Authors: Wang Xinchen , Liu Yuwei , Liu Yaofeng
Published: November 2024

The supersonic/hypersonic jet interaction flow field includes many fluid phenomena such as shock waves, separation and reattachment of the boundary layer, expansion wave, Mach disk, shear layer, and so on. The complexity of the jet interaction flow field makes it difficult to simulate accurately, and the structured grid method is generally used in engineering applications. However, the structured grid has many shortcomings when dealing with complex configurations, and the traditional hybrid grid method has the problem of insufficient accuracy. In the paper, a structured/unstructured grid algorithmic coupling numerical simulation method is developed. Firstly, the feasibility and accuracy of this method are verified by numerical simulation of the jet interference flow field of cone-cylinder-skirt shape, along with a comparison with the results of the experiment and structural method. Then, the jet interference flow fields of the rudders and the grid fins configuration are simulated to show the efficiency of the method, and the accuracy is further verified. The results show that the hybrid numerical simulation method can save grid generation time and grid quantity to a certain extent when compared with the structural, showing higher accuracy, which provides an accurate and efficient solution to jet interaction problems with complex configurations.
Wing optimization for static aeroelastic effect
Authors: Sun Zexu
Published: November 2024

An aeroelastic analysis module based on the VLM model and FE model with non-linear static analysis was developed to calculate the lift and deformation of a wing in a cruise case. The traditional static aeroelastic analysis method focuses on compensation of loss of lift by adjusting wing root AoA (angle of attack). To improve the aeroelastic property, integrated static aeroelastic optimization was developed, which compensates for the loss lift by adjusting a series of sectional AoA instead of only wing root AoA. Compared with traditional static aeroelastic analysis, the manufacture wing optimized by integrated static aeroelastic optimization is closer to the initial design wing.
Efficient conversion of Euler angles to quaternion for practical aerospace applications
Authors: Liu Ruirui , Wang Zhaohui , Zhang Jian , Fang Juan
Published: November 2024

Current methods for converting Euler angles to a rotation quaternion are computationally intensive and have limited practical applications in aerospace. This study introduces an efficient approach that directly converts Euler angles in any desired sequence to a rotation quaternion, eliminating the need for intermediate Euler angle transformation matrices, which leads to a significant improvement in computational efficiency. Moreover, it is general because it works with all 12 possible sequences of rotations. A case study is presented, demonstrating the application of the algorithm in converting between the launch frame and the missile frame of a vertical takeoff vertical landing (VTVL) rocket. The results show more than a ninefold improvement in computational efficiency compared to the classical Euler angle method while maintaining consistency of results.
A density-functional theory study of the interaction of rimantadine drug molecule with X-doped fullerene (X = B, Al, Ga, Si, Ge, BN, AlN, GaN, SiN, GeN)
Authors: Kristiawan Bambang , Apriati Yosephine Novita , Nugraheni Ari Dwi , Sholihun Sholihun
Published: November 2024

This research investigated the interaction of rimantadine (RMT) drug molecule with fullerene C60 and heterofullerenes through density-functional theory calculations. Heterofullerene was used as a nanomaterial through the introduction of the following dopants into fullerene C60: B, Al, Ga, Si, Ge, BN, AlN, GaN, SiN, GeN, AlN2, AlN3, (AlN3)2, (AlN)3, (AlN2)3, and (AlN3)3. The adsorption energy and charge transfer were analyzed to investigate the interaction between RMT and heterofullerene. The addition of the N dopant to C59Al heterofullerene enhanced the adsorption energy, which enabled the transport of three molecules of the RMT drug.
Category 𝒞_{𝓀} of multi-loop algebra representations versus modular representations: Questions of G. Lusztig
Authors: Kumar Shrawan
Published: November 2024

Lusztig defined an abelian category

C

k

{\mathscr {C}}_{k}

of a class of representations of a multi-loop algebra and asked various questions connecting it to the modular representation theory of simple algebraic groups in char.

p
>
0

p>0

. The aim of this paper is to show that some of these questions have negative answer.
Max Weber after 100 Years
Authors: Derman Joshua , Gordon Peter E
Published: November 2024

The editors’ introduction to Max Weber at 100 surveys Weber’s career and the profound impact of his thought on the development of the modern humanities and social sciences. It traces the networks of his reception and identifies the key aspects of his oeuvre that have engaged generations of admirers and critics: his theses about the emergence of modern capitalism, his comparative historical analysis, his methodological and philosophical writings, and the force of his charismatic personality. Weber’s intuitive understanding of the tensions of modern life has generated enduring fascination. His presence at the intersection of major political and academic controversies has also affected the reception of his work. The editors argue that Weber’s legacy in the next 100 years will be shaped by his theories about ecology, global capitalism, imperialism, democracy, and gender; and his philosophical observations concerning questions of human nature, value freedom, objectivity, secularization, rationalization, and disenchantment.
The Power of the Sacred
Authors: Joas Hans
Published: November 2024

Hans Joas’s 2017 book, translated into English in 2021 as The Power of the Sacred: An Alternative to the History of Disenchantment, presents a powerful critique of Max Weber’s famous notion of the “disenchantment of the world” and its legacy for the sociology of religion. By subjecting the narratives and concepts in Weber’s theorizing to rigorous analysis, Joas seeks to emancipate sociology from “dangerous nouns of process.” The editors of Max Weber at 100 engaged Joas in a wide-ranging dialogue about the book’s argument; the utility of concepts such as disenchantment, rationalization, and value-sphere differentiation; the role of ideal types in social science research; charisma and polytheism; and the enduring value of Weber’s comparative-historical scholarship. The conversation elucidates the challenges that confront Weberian sociology as well as the resources that continue to make Weber’s scholarship relevant in the twenty-first century.
Refining MRI protocols for endometriosis: a comparative study of abbreviated and full MRI sequences
Authors: Arian Arvin , Karimi Nafise , Ahmadinejad Nasrin , Azadnajafabad Sina , Delazar Sina
Published: November 2024

Objectives

Endometriosis is a significant cause of chronic abdominal pain and infertility in females, often overlooked due to its resemblance to other abdominopelvic pathologies. This study aims to compare the diagnostic performance and agreement rate between an abbreviated MRI protocol (aMRI) and a full MRI protocol (fMRI) for detecting pelvic endometriosis.

Methods

We retrospectively analysed 446 consecutive MRI exams, including both full (fMRI) and abbreviated (aMRI) protocols, performed for suspected pelvic endometriosis. An expert radiologist assessed the presence of endometriosis at 14 distinct anatomical sites. Each MRI protocol was interpreted in random order, with a minimum two-week interval between sessions to minimize recall bias. Agreement between the protocols was evaluated using kappa statistics.

Results

The average age of the patients was 34.13 years. The highest incidences of endometriosis were found in the ovaries (88.8%) and the recto-uterine pouch (65%). The MRI protocols demonstrated perfect agreement (kappa coefficient = 1) for the ovaries, bladder, uterus, and caesarean section scar. High agreement was also observed in the rectum and uterine ligaments (kappa coefficients of 0.98 and 0.97). Detection of malignant transformation in existing ovarian endometriomas showed substantial concordance with a kappa coefficient of 0.66.

Conclusions

An abbreviated non-contrast MRI protocol exhibits diagnostic accuracy comparable to that of a comprehensive protocol in detecting pelvic endometriosis, with similar confidence and reproducibility.

Advances in knowledge

This study demonstrates that an abbreviated MRI protocol is as effective as a full protocol in diagnosing pelvic endometriosis, potentially allowing for quicker, cost-effective imaging without compromising diagnostic accuracy.
Papular elastorrhexis: recognizing an uncommon entity
Authors: Muddebihal Aishwarya , Arora Pooja , Batrani Meenakshi
Published: November 2024

Papular elastorrhexis presents as asymptomatic, multiple, discrete, nonfollicular, skin-coloured papules of size ranging from 1 to 5 mm with no tendency to coaslesce. The aetiology of papular elastorrhexis remains largely unclear. It is a benign, treatment-resistant disease with only cosmetic implications and affected patients must be counselled regarding the same. We report the case of a 21-year-old woman with papular elastorrhexis. It should be differentiated from naevus anelasticus, papular acne scars, eruptive collagenoma, disseminated lenticular dermatofibrosis, anetoderma, pseudoxanthoma elasticum and mid-dermal elastolysis. Recognition of this entity is important for patient counselling regarding the benign nature of disease with cosmetic implications.
Convolutional neural networks uncover the dynamics of human visual memory representations over time
Authors: Zohar Eden , Kozak Stas , Abeles Dekel , Shahar Moni , Censor Nitzan
Published: November 2024

The ability to accurately retrieve visual details of past events is a fundamental cognitive function relevant for daily life. While a visual stimulus contains an abundance of information, only some of it is later encoded into long-term memory representations. However, an ongoing challenge has been to isolate memory representations that integrate various visual features and uncover their dynamics over time. To address this question, we leveraged a novel combination of empirical and computational frameworks based on the hierarchal structure of convolutional neural networks and their correspondence to human visual processing. This enabled to reveal the contribution of different levels of visual representations to memory strength and their dynamics over time. Visual memory strength was measured with distractors selected based on their shared similarity to the target memory along low or high layers of the convolutional neural network hierarchy. The results show that visual working memory relies similarly on low and high-level visual representations. However, already after a few minutes and on to the next day, visual memory relies more strongly on high-level visual representations. These findings suggest that visual representations transform from a distributed to a stronger high-level conceptual representation, providing novel insights into the dynamics of visual memory over time.
Atlantic Trade and Conflict in Europe
Authors: Ahsan Reshad N , Panza Laura , Song Yong
Published: November 2024

We use over 200 years of conflict and wheat price data to provide the first quantitative evidence that Atlantic trade reduced conflict in Europe. While other determinants of intra-European conflict during the Early to Late Modern period have been proposed, the role of Atlantic trade has not been previously explored due to a lack of historical trade data. We overcome this constraint by using wheat prices to calculate time-varying measures of price pass-through between Europe and the New World, which we use as a proxy for Atlantic trade. To identify the causal effects of Atlantic trade, we exploit exogenous changes in wind patterns and tropical cyclone activity over the Atlantic Ocean to instrument trade. Our results suggest that a one-standard-deviation increase in Atlantic trade resulted in a 0.157-standard-deviation decrease in intra-European conflict onset. We also find empirical support for Atlantic trade increasing real wages and reducing military sizes in Europe, which is consistent with the idea that the possibility of forgone Atlantic trade acted as a deterrent to conflict.
Evolocumab treatment reduces carotid intima-media thickness in paediatric patients with heterozygous familial hypercholesterolaemia
Authors: Wiegman Albert , Ruzza Andrea , Hovingh G Kees , Santos Raul D , Mach François , Stefanutti Claudia , Luirink Ilse K , Bridges Ian , Wang Bei , Bhatia Ajay K , Raal Frederick J , Kastelein John J P , Gaudet Daniel
Published: November 2024

Aims

Children with heterozygous familial hypercholesterolaemia (HeFH) show greater carotid intima-media thickness (cIMT). Evolocumab, a proprotein convertase subtilisin/kexin type 9 inhibitor monoclonal antibody, substantially reduced LDL cholesterol (LDL-C) in children with HeFH. We investigated evolocumab’s effect on cIMT progression.

Methods and results

HAUSER-RCT was a randomized, placebo-controlled trial. One hundred fifty-seven paediatric patients with FH (age: 10–17 years) and LDL-C > 130 mg/dL despite statin therapy received monthly evolocumab 420 mg or placebo for 24 weeks. Patients who continued into an open-label extension (OLE) (HAUSER-OLE; n = 150) received 80 weeks of monthly evolocumab plus statins. Carotid intima-media thickness was measured by B-mode ultrasound scanning of right and left common carotid artery at baseline; Week 24 of randomized controlled trial (RCT) (Day 1 OLE); and Weeks 24, 48, and 80 of OLE. Descriptive analysis of cIMT was a pre-specified HAUSER secondary endpoint, and inferential tests reported here were post hoc. One hundred fifty-one patients had evaluable cIMT summary scores at ≥ 1 visit. From RCT baseline to Week 24, mean cIMT increased by 0.006 mm (SD = 0.05) with placebo (n = 37) and decreased by 0.003 mm (SD = 0.05) with evolocumab (n = 76). From RCT baseline to OLE Week 80, mean cIMT summary score decreased by 0.019 mm (SD = 0.04) and 0.012 mm (SD = 0.05), respectively, in patients who initially received placebo (n = 34, P = 0.007) vs. receiving evolocumab throughout (n = 59, P = 0.067). Across patients who received evolocumab in OLE, mean cIMT significantly decreased by 0.011 mm (SD = 0.05) from OLE Day 1 to Week 80 (n = 94, P = 0.034).

Conclusion

In children with HeFH, evolocumab plus statin treatment up to 104 weeks led to regression in carotid arterial wall thickening.

Registration

ClinicalTrials.gov: NCT02624869
Integrative systematics of Cheguevaria Kazantsev, 2007 (Coleoptera, Lampyridae, Cheguevariinae) identifies genetic stability in color-polymorphic individuals and a disjoint relationship with Amydetinae
Authors: Ferreira Vinicius S , Keller Oliver , Barbosa Felipe Francisco , Ivie Michael A
Published: November 2024

The genus Cheguevaria (Kazantsev 2007) is currently comprised of three species which are endemic to the Greater Antilles: Cheguevaria angusta Kazantsev, 2007 (Hispaniola), Cheguevaria taino Kazantsev, 2007 and Cheguevaria montana Kazantsev, 2008 (both from Puerto Rico). Cheguevaria is the sole member of Cheguevariinae, and a previous morphology-based phylogenetic hypotheses suggested a close relationship with the subfamily Amydetinae. Recent collecting trips to Puerto Rico and the survey of other scientific collections allowed us to identify and locate more specimens of the genus, including several color morphs of specimens tentatively identified as C. montana. We used this material to revise the genus, and to describe Cheguevaria cubensisnew species, the first record of the genus from Cuba. We also produced DNA barcodes based on partial cytochrome c oxidase subunit 1 (COI), which were used to investigate the species limits within color morph species of C. montana. Our results showed a high level of genetic stability in those color morphs, indicating that all specimens belong to the same species. We present a discussion to explain possible scenarios leading to such variation in color patterns. We also generated amplicons for two specimens of Amydetinae, represented by two Amydetes Illiger, 1807 species, and we tested their relationship with Cheguevaria in a phylogenetic context based on a four gene dataset. Our analyzes indicated a disjoint relationship between Cheguevaria and Amydetes, corroborating previously published morphology-based phylogenies, and we maintained the status of Cheguevaria as an independent lineage within Lampyridae.
Machine learning-based infection diagnostic and prognostic models in post-acute care settings: a systematic review
Authors: Xu Zidu , Scharp Danielle , Hobensack Mollie , Ye Jiancheng , Zou Jungang , Ding Sirui , Shang Jingjing , Topaz Maxim
Published: November 2024

Objectives

This study aims to (1) review machine learning (ML)-based models for early infection diagnostic and prognosis prediction in post-acute care (PAC) settings, (2) identify key risk predictors influencing infection-related outcomes, and (3) examine the quality and limitations of these models.

Materials and Methods

PubMed, Web of Science, Scopus, IEEE Xplore, CINAHL, and ACM digital library were searched in February 2024. Eligible studies leveraged PAC data to develop and evaluate ML models for infection-related risks. Data extraction followed the CHARMS checklist. Quality appraisal followed the PROBAST tool. Data synthesis was guided by the socio-ecological conceptual framework.

Results

Thirteen studies were included, mainly focusing on respiratory infections and nursing homes. Most used regression models with structured electronic health record data. Since 2020, there has been a shift toward advanced ML algorithms and multimodal data, biosensors, and clinical notes being significant sources of unstructured data. Despite these advances, there is insufficient evidence to support performance improvements over traditional models. Individual-level risk predictors, like impaired cognition, declined function, and tachycardia, were commonly used, while contextual-level predictors were barely utilized, consequently limiting model fairness. Major sources of bias included lack of external validation, inadequate model calibration, and insufficient consideration of data complexity.

Discussion and Conclusion

Despite the growth of advanced modeling approaches in infection-related models in PAC settings, evidence supporting their superiority remains limited. Future research should leverage a socio-ecological lens for predictor selection and model construction, exploring optimal data modalities and ML model usage in PAC, while ensuring rigorous methodologies and fairness considerations.
Labral size measured on preoperative magnetic resonance imaging not predictive of the need for labral reconstruction in patients undergoing primary hip arthroscopy
Authors: Peszek Adam , Alder Catherine C , Jamar Kyle , Wait Trevor J , Wipf Caleb J , Keeter Carson L , Mayer Stephanie W , Ho Charles P , Genuario James W
Published: November 2024

Preoperative radiographic measurements may help predict which patients with hip labral tears ultimately undergo repair versus primary reconstruction. This study investigated if radiographic parameters: (i) preoperatively predict labral repair versus reconstruction and (ii) correlate with T2 magnetic resonance imaging (MRI) mapping values of the labrum. This retrospective comparative study included patients aged 14–50 years who underwent labral repair or reconstruction at a single institution over a 2-year period. Patients with prior open or arthroscopic hip surgery or who had inadequate preoperative computed tomography (CT) and MRI imaging were excluded. Labral size was measured at multiple positions on preoperative MRI images. A blinded reviewer used three-dimensional CT analysis to record lateral center edge angle (LCEA), acetabular version, Tonnis angle, acetabular coverage, alpha angle, femoral torsion, and neck-shaft angle (FNSA). T2 MRI mapping values of the labrum were obtained via sequencing analyses on each patient’s optimal sagittal cut. Univariate mixed linear models were used to identify associations between each radiographic measurement and decision to repair or reconstruct the labrum. Fifty-two operations were included. Labral size had no predictive effect on undergoing labral reconstruction versus repair. Likelihood for undergoing labral reconstruction was associated with LCEA (P = .003) and Tonnis angle (P = .034). There was an association (P < .05) between labral T2 mapping values and all radiographic parameters except for FNSA and combined version. Labral size was not associated with whether patients underwent labral reconstruction or repair. The data showed an association between labrum T2 mapping values and nearly all radiographic parameters.
The Trickster archetype: education to stupefy
Authors: Dhillon Sunny
Published: November 2024

Contra the teleological paradigm of the Hero, this article argues that incorporating an ethic of the Trickster archetype may facilitate greater critical thinking and metacognition within contemporary neoliberal Education Studies learning environments in UK Higher Education. Echoing Lewis’ call for an education to stupefy, as well as Bojesen’s argument for treating Education Studies as a labour of the negative, I present the Trickster archetype as a valuable mode of educational engagement (an endeavour which itself must be done in a paradoxical fashion, for the Trickster ethic cannot be neatly prescribed). In this manner, the ethos of Trickster practices is, I suggest, one of generativity and what Greene calls ‘releasing the imagination’. As opposed to fixing us to any supposed Archimedean standpoint, Trickster practices encourage us to consider radical alternative possibilities from within normative discourse through immanent critique. I argue that the Trickster ethic foregrounds contingency over apparent necessity. I also explore how the Trickster may, paradoxically, be given a concomitant atelic aspiration in association with both Perry’s linear stages of contextual reasoning and metacognition. I conclude by elucidating the ethical and practical problems that accompany attempts to instantiate a Trickster ethic, given that it threatens, and faces possible repudiation from, those with vested interest in upholding dominant mores.
Cosmological foundations revisited with Pantheon+
Authors: Lane Zachary G , Seifert Antonia , Ridden-Harper Ryan , Wiltshire David L
Published: November 2024

We reanalyse the Pantheon+ supernova catalogue to compare a cosmology with non-FLRW evolution, the timescape cosmology, with the standard ΛCDM cosmology. To this end, we analyse the Pantheon+ for a geometric comparison between the two models. We construct a covariance matrix to be as independent of cosmology as possible, including independence from the FLRW geometry and peculiar velocity with respect to FLRW average evolution. This framework goes far beyond most other definitions of model independence. We introduce new statistics to refine Type Ia supernova (SNe Ia) light-curve analysis. In addition to conventional galaxy correlation functions used to define the scale of statistical homogeneity we introduce empirical statistics which enables refined analysis of the distribution biases of SNe Ia light-curve parameters βc and $\alpha {x_{\lower2pt\hbox{$\scriptstyle 1$}}}$. For lower redshifts, the Bayesian analysis highlights important features attributable to the increased number of low-redshift supernovae, the artefacts of model-dependent light-curve fitting and the cosmic structure through which we observe supernovae. This indicates the need for cosmology-independent data reduction to conduct a stronger investigation of the emergence of statistical homogeneity and to compare alternative cosmologies in light of recent challenges to the standard model. Dark energy is generally invoked as a place-holder for new physics. For the first time, we find evidence that the timescape cosmology may provide a better overall fit than ΛCDM and that its phenomenology may help disentangle other astrophysical puzzles. Our from-first-principles reanalysis of Pantheon+ supports future deeper studies between the interplay of matter and nonlinear spacetime geometry in a data-driven setting.