bluuebunny/crossref_metadata_2025 huggingface dataset:
Explanations for the two-component spectral energy distributions of gravitationally lensed stars at high redshifts
Authors: Nabizadeh Armin , Zackrisson Erik , Lundqvist Emma , Ricotti Massimo , Park Seyong , Welch Brian , Diego Jose M.
Published: December 2024

Observations of gravitationally lensed, high-mass stars at redshifts ≳1 occasionally reveal spectral energy distributions that contain two components with different effective temperatures. Given that two separate stars are involved, this suggests that both stars have simultaneously reached very high magnification, as expected for two stars in a binary system close to the caustic curve of the foreground galaxy-cluster lens. The inferred effective temperatures and luminosities of these stars are, however, difficult to reconcile with known binaries, or even with isolated stars of the same age. Here, we explore three alternative explanations for these cases: circumstellar dust around the cooler of the two stars, age differences of a few million years among stars in the same star cluster, and a scenario in which the stars originate in two separate star clusters of different age along the lensing caustic. While all of these scenarios are deemed plausible in principle, dust solutions would require more circumstellar extinction than seen in local observations of the relevant supergiant and hypergiant stars. Hence, we argue that age differences between the two stars are the most likely scenario, given the current data.
Breaking the cosmological invariance of the dark-matter halo shape as a new probe of modified gravity
Authors: Koskas Rémy , Alimi Jean-Michel
Published: December 2024

In a recent paper, we highlighted in wCDM models derived from general relativity (GR) (with Dark Energy Universe numerical simulation data), a cosmological invariance of the distribution of dark-matter (DM) halo shapes when expressed in terms of the nonlinear fluctuations of the cosmic matter field. This paper shows that this invariance persists when tested on numerical simulations performed with a different N-body solver, and that it is also robust to adding massive neutrinos to the cold DM component. Furthermore, this discovery raises crucial questions about the validity of this invariance in MG models. Thus, we examined whether it remains robust in the case of Hu & Sawicki model using DUSTGRAIN-pathfinder numerical simulations. By comparing the results of advanced numerical simulations in these different theoretical frameworks, we found significant deviations from the invariance observed in the framework of wCDM models of GR. These deviations suggest that the gravitation’s nature significantly influences the DM halos’ shape. We then interpreted this departure from the GR models’ invariance as a manifestation of the scalar-field screening effect corresponding to such f(R)-type theories. This one modifies the sphericization process of DM halos during their formation, precisely because the critical mass at which this scalar field becomes non-negligible is the mass at which the deviation appears. To this extent, the departure from cosmological invariance in DM halos’ shape is a cosmological probe of the nature of gravity, and the mass scale at which it appears can be used to estimate the fR0 parameter of such theories.
Combining remote sensing surveys, digital and in situ field trips in higher education geology classroom
Authors: Jaud Marion , Agranier Arnaud , Graindorge David , Kernec Maxime , Delacourt Christophe
Published: December 2024

The OceanField project is an integrated field-work and classroom-based course offered to first year Master students in Marine Geosciences (at the European Institute for Marine Studies IUEM – University of Brest), creating a synergy between 1/ geology field class, 2/ photogrammetric data acquisition and 3/ data processing to produce digital terrain models, enabling the immersive experience to be extended in a digital working environment once back in class.
In this way, the students experiment different approaches for observing and analysing the structure, geometry and nature of a past oceanic domain in the Alps, and gain an understanding of how it works (from its birth to its disappearance). At the same time, participating in the acquisition and processing of photogrammetric data, students acquire new technical skills. By not only being immersed in the virtual environment, but also contributing to its creation, students are involved in the various stages of the data lifecycle. As a result, they become more aware of multiscale data quality and of the opportunities offered by virtual environment accuracy.
MC21 v.10 – coupled-radiation Monte Carlo transport solver with support for multiphysics simulations
Authors: Griesheimer David P. , Gill Daniel F. , Nease Brian R. , Pavlou Andrew , Stedry Mark H. , Thompson Jason T. , Burke Paul E. , Dobreff Peter S.
Published: December 2024

Over the past decade, the development of the MC21 Monte Carlo radiation transport solver has focused on extending the functionality of the code beyond static calculations of reactivity and reaction rate distributions, as well as improving accuracy, performance, and scalability. Notable improvements include enhanced interaction physics models, efficient model representation and tracking algorithms, support for coupled physics calculations using both in-line and externally coupled feedback modules, and the development of native visualization and results post-processing tools. As a result of these improvements, MC21 v.10 provides a comprehensive analysis framework that allows complicated engineering problems to be solved with minimal reliance on external tools.
Optimal Long-term Antiplatelet Regimen for Patients with High Ischaemic and Bleeding Risks After Percutaneous Coronary Intervention
Authors: Jang Jeong Yoon , Ga-In Yu , Jongwha Ahn , Bae Jae Seok , Yun-Ho Cho , Kang Min Gyu , Koh Jin Sin , Jeong Young-Hoon , Sang Yeup Lee , Byeong-Keuk Kim , Hyung Joon Joo , Do-Sun Lim , Chang Kiyuk , Bin Song Young , Sung Gyun Ahn , Suh Jung-Won , Jung Rae Cho , Kim Hyo-Soo , Kim Moo Hyun Hyun , Shin Eun Seok , Park Yongwhi
Published: December 2024

Aim
To assess an optimal long-term antiplatelet strategy in patients at both high ischaemic and bleeding risks after percutaneous coronary intervention (PCI).
Methods and results
Patients both at high ischaemic and bleeding risks were eligible for inclusion. We excluded patients with any ischaemic and major bleeding complications during the mandatory period of dual antiplatelet therapy (DAPT). Clinical outcomes were evaluated in three groups of regimen, in terms of, clopidogrel monotherapy (CLPD), aspirin monotherapy (ASA) and DAPT group. The primary endpoint was a composite of all-cause death, myocardial infarction, stroke or major bleeding for 12-month follow-up period. To balance characteristics according to antiplatelet strategies, stabilized inverse probability treatment weighting (IPTW) was conducted. After IPTW adjustment, CLPD group (N=916) showed the significantly lower rate of primary endpoint than DAPT group (N=949) (Hazard Ratio [HR]=2.09, 95% confidence interval (CI)= 1.22 - 3.60, p=0.008], but there was no statistical difference between CLPD and ASA (N=838) groups (HR=1.46, 95% CI=0.83-2.54, p=0.187). Clinical benefits of CLPD over DAPT was mainly driven by the lower incidence of ischaemic events (HR = 2.51, 95% CI 1.37-4.61; p = 0.003). Incidence of major bleeding did not differ among groups, but there was an increased bleeding tendency in DAPT group compared to CLPD group (HR=2.51, 95% CI=0.85-7.41, p=0.096).
Conclusion
For patients at high bleeding and ischaemic risk especially undergoing complex PCI, clopidogrel monotherapy demonstrated a significant net clinical benefit compared to DAPT. Clopidogrel monotherapy showed numerical reductions of bleeding and ischaemic event rates compared to aspirin monotherapy.
Comparison of Chlorhexidine Gluconate, Sodium Hypochlorite, Neem Extract, and Microwave Radiation for Disinfection of Type IV Dental Stone
Authors: Jabeen Bushra , Mirani Zulfiqar A. , lone Muneeb A. , Nirkhiwale Arpit , Farooqui Waqas A. , Aslam Kashif , Ahmed Muhammad Adeel , Vohra Fahim
Published: December 2024

Objective The present study evaluated the effect of chemical disinfectants and microwave sterilization on the removal of biofilm containing Pseudomonas aeruginosa, Streptococcus mutans, and Candida albicans from type IV dental stone.

Materials and Methods One hundred twenty-eight (N = 128) type IV dental cast stone specimens were prepared, and biofilms of microorganisms were cultured. Dental stone samples were subjected to disinfection protocols, including 0.5% chlorhexidine (CHX), 0.5% sodium hypochlorite (NaOCl), 20% neem extract, and microwave irradiation for 1 to 5 minutes. Colony forming unit (CFU) counts and scanning electron microscopy were utilized to witness changes in the biofilm, pre- and postdisinfection/sterilization.

Results For P. aeruginosa, significant (p < 0.05) decrease in CFU counts after 1 minute (from 233 to −215) and 2, 3, and 5 minutes (from 233 to −233) were observed after CHX treatment. After microwave radiation, a significant decrease in CFU counts was also observed after 1 minute (from 233 to −130.3), 2 minutes (from 233 to −229), and 3 and 5 minutes (from 233 to −233). For S. mutans, a significant (p < 0.05) decrease in CFU counts was observed after 1, 2, 3, and 5 minutes (from 212 to −268) after NaOCl treatment and microwave radiation (from 212 to −271 after 1 minute and from 212 to −274.3 after 2, 3, and 5 minutes). For C. albicans, significant (p < 0.05) decrease in the CFU counts (1–5 minutes) was observed after CHX exposure, while NaOCl and microwave radiation demonstrated equal disinfection potency. Neem extract was effective to disinfect the dental stone; however, it was not as potent as the other disinfectants and microwave radiation.

Conclusion It was observed that exposure to CHX, NaOCl, and microwave radiation significantly reduced the microbial CFU counts. Although the use of neem extract also significantly reduced these CFU counts, this reduction was not as much as the other three tested materials. Further research exploring other chemical disinfectants with various concentrations is recommended.
The Relationship between Personality Trait and Dental Anxiety in Students of Health-Related Specialties: A Pilot Study
Authors: Khatib Dania Al , Altaheri Sereen , Sabh Mera Ismail Al , Elshirbiny Haydi , Masaad Hiyam Adel , AlAbdullah Tayebah , Alsumait Sarah , Alsulaili Hanouf , Buhamad Fatimah , Al-Rawi Natheer Hashim
Published: December 2024

Objectives Dental anxiety is a common issue affecting a significant portion of the population, often leading to avoidance of dental care and subsequent oral health problems. Understanding the underlying factors contributing to dental anxiety is a crucial step toward developing an effective intervention. The aim of the study was to assess the prevalence of dental anxiety among students of health-related majors, evaluate their personality traits, and find the correlation between them. Additionally, this study aims to find the predictors of such traits and their relationship with each other.

Materials and Methods The study was conducted on 163 consented students (124 males and 39 females), selected based on major and year of study at the University of Sharjah medical campus. The questionnaire was sent online through Google Forms. It included questions from the Modified Dental Anxiety Scale (MDAS)and the Big Five personality test. Data analysis was done using SPSS software (IBM Co. version 29) where all descriptive and inferential statistics were conducted with statistical significance set at p < 0.05.

Results Moderate level of dental anxiety (12.3 ± 5.8) was observed among students of the medical campus, where nondental students scored higher in mean dental anxiety (13.0 ± 6.2) compared with dental students (10.4 ± 4.5). Males scored higher on the dental anxiety scale (12.5 ± 5.8) compared with females (11.7 ± 5.6). The Big Five personality test results displayed statistical significance association between neuroticism and dental anxiety, compared with other measured parameters (p < 0.05).

Conclusion Neuroticism (Big Five characteristics scoring) and dental anxiety (MDAS scoring) exhibit a significant correlation. The Big Five test's characteristics are interrelated, including neuroticism and conscientiousness which, in turn, had a substantial correlation with agreeableness. Subsequently, agreeableness, conscientiousness, and extraversion exhibit substantial correlations with openness. This dynamic between the traits indicates that the adoption of personality tests in dental clinics would lead to improved prediction and management of dental anxiety in health-related students.

Clinical Relevance Since dentistry relies on patient management to get the best results, understanding the relationship between personality factors and dental anxiety might enhance patient management. This would prevent health care neglect and undiagnosed oral problems.
Precision in Neuronavigation Systems: A Systematic Review and Meta-analysis
Authors: Santos Evelen Rouse de Souza , Viana Fabiana Ramos , Gonçalves Paulo Eduardo , Lima Maria Adriely Cunha , Lyra Carlos Alberto Miranda , Santos Bruno Fernandes de Oliveira
Published: December 2024

Introduction To evaluate the accuracy of different neuronavigation systems and establish factors that influence their accuracy and their indications for use.

Methods This is a systematic review of the literature with meta-analysis based on the guiding question of the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA): What is the accuracy of neuronavigation systems and the factors that influence it? For that, a search was performed in PubMed, LILACS, SciELO, Embase, Web of Science, and SCOPUS databases using descriptors combined with two Boolean operators. The articles found were submitted to eligibility criteria, and the reading was partial and complete. A total of 51 studies were selected, and 11 were included in the meta-analysis.

Results In total, 5,316 procedures were evaluated using neuronavigation systems and different types of procedures performed on the skull and spine. After meta-analysis, it was possible to establish the accuracy of the optical (N = 297) and AR (N = 195), with SBT of 2.34 mm and 2.09 mm, respectively. However, studies were evaluated regarding the influence of different recording methods, the use of associated technologies, and their indications for use.

Conclusions The accuracy of the systems was established through the TRE of 2.34 mm for the optical and 2.09 mm for the augmented reality, while it was not possible to establish the electromagnetic one. Thus, the ARN is the system with the best accuracy value, in addition to presenting advantages during the surgical period when compared with the others.
Scalable learning of potentials to predict time-dependent Hartree–Fock dynamics
Authors: Bhat Harish S. , Gupta Prachi , Isborn Christine M.
Published: December 2024

We propose a framework to learn the time-dependent Hartree–Fock (TDHF) inter-electronic potential of a molecule from its electron density dynamics. Although the entire TDHF Hamiltonian, including the inter-electronic potential, can be computed from first principles, we use this problem as a testbed to develop strategies that can be applied to learn a priori unknown terms that arise in other methods/approaches to quantum dynamics, e.g., emerging problems such as learning exchange–correlation potentials for time-dependent density functional theory. We develop, train, and test three models of the TDHF inter-electronic potential, each parameterized by a four-index tensor of size up to 60 × 60 × 60 × 60. Two of the models preserve Hermitian symmetry, while one model preserves an eight-fold permutation symmetry that implies Hermitian symmetry. Across seven different molecular systems, we find that accounting for the deeper eight-fold symmetry leads to the best-performing model across three metrics: training efficiency, test set predictive power, and direct comparison of true and learned inter-electronic potentials. All three models, when trained on ensembles of field-free trajectories, generate accurate electron dynamics predictions even in a field-on regime that lies outside the training set. To enable our models to scale to large molecular systems, we derive expressions for Jacobian-vector products that enable iterative, matrix-free training.
Excavation deformation analysis of subway foundation pits based on finite element analysis
Authors: Li Yingchao , Liu Zhao
Published: December 2024

The excavation deformation of subway foundation pit engineering is limited by the engineering characteristics. There is a risk of collapse lag and incalculable consequences. To improve the safety factor in subway foundation pit construction and prevent the risk of foundation pit collapse, finite element analysis was utilized to simulate the deformation of subway foundation pit excavation. Meanwhile, a risk assessment method for the collapse of foundation pit support was constructed by combining the fuzzy hierarchical comprehensive evaluation model in the experiment. Numerical analysis confirmed that the maximum horizontal displacement of the foundation pit when excavated to the bottom was 11.96 mm, and the maximum surface settlement was 11.50 mm. These simulation results were highly consistent with the measured curve, with a maximum displacement difference of only 2.87 mm and a maximum settlement difference of 2.00 mm. According to the proposed method, foundation pit engineering’s evaluation was carried out, with a support structure score of 0.437, a surrounding soil score of 0.450, a bottom soil score of 0.267, and an overall project risk score of 0.416, all within an acceptable range. Therefore, the method of simulating and predicting excavation deformation of subway foundation pits using the finite element software is effective and reliable. According to the risk assessment results of foundation pit collapse, relevant management personnel should strengthen and attach importance to the prevention of collapse of the surrounding soil and support structures of the foundation pit.
Coupling x-ray computed tomography and gray-level co-occurrence matrix to assess the evolution of microstructural damage in coal treated with supercritical CO2 fluid
Authors: Luo Peng , Zhang Zhenyu , Zhang Lei , Xue Kangsheng , Liu Zhenjian
Published: December 2024

The reliability of segmentation of x-ray computed tomography (CT) images based on user-selected thresholds is important for analyzing supercritical CO2 (ScCO2)-water-induced microstructural damage in coal. In this study, a novel approach is introduced by integrating the gray-level co-occurrence matrix (GLCM) method with CT to analyze the evolution of microstructural damage in coal treated by ScCO2-water. The factors influencing GLCM calculation are also examined. GLCM heat maps and statistics were employed to visualize and quantitatively analyze the evolution of microstructural damage. The results show that the application of image grayscale registration and noise reduction to GLCM statistics did not produce directional bias, with noise reduction having a more significant impact. The pixel pairings depicted in GLCM heat maps provide insights into the spatial distribution of pore-fracture (in the low-density quadrant) and mineral components (in the high-density quadrant) within CT images, elucidating the evolution of micro-damage in coal samples. After the ScCO2-water treatment, a conspicuous rise in pixel pair counts within the low-density quadrant can be observed, accompanied by significant dissolution of the highest-density minerals, leading to a maximal reduction in pixel values within the high-density quadrant. Moreover, GLCM statistics show that the maximum damage location after ScCO2-water treatment does not completely match the initial coal. An accurate description of the evolution of GLCM statistics in the structural damage behavior induced by CO2 injection into deep coal-rock reservoirs is crucial, suggesting that these GLCM statistics have the potential to predict structural damage and reservoir instability during the geological sequestration of CO2.
Development of Fully Self-Controllable High-Finesse Optical Reference Cavities
Authors: Jiao Dongdong , Wu Mengfan , Gao Jing , Zhang Han , Liu Junlong , Xu Guanjun , Zang Qi , Cui Jie , Dong Ruifang , Liu Tao , Qu Bo , Zhang Shougang
Published: December 2024

High-finesse optical reference cavities are essential tools for fundamental research. In response to China’s historical reliance on importing high-finesse optical reference cavities, we successfully developed a cavity using ultralow expansion glass (ULE) materials and processed it entirely in China. Using the method of measuring the cavity linewidth, a finesse of approximately 480000 was obtained in our experiments. We adopted a relatively simple and effective approach to test the optical reference cavity, which involved measuring the resonant points using an ultrastable laser. Remarkably, an expansion coefficient of the Chinese ULE optical reference cavity reached up to the order of 10−9/K within the temperature range of 27 °C to 40 °C, with the zero expansion point occurring at approximately 34 °C. These findings demonstrate China’s independent capability to develop high-finesse optical reference cavities, which is a significant advancement in precision optics.
Explaining the singular oscillator: physical considerations and mechanical analogies
Authors: Kontomaris Stylianos Vasileios , Malamou Anna
Published: December 2024

Nonlinear oscillations in one dimension are typically described by a general differential equation of the form x″ + f(x) = 0. In many classical systems, oscillations occur around an equilibrium position, defined where f(x) = 0. A notable exception is the singular oscillator, where f(x) = c/x, with c as a positive constant. Despite extensive studies yielding approximate periodic solutions expressed as series of sinusoidal functions, the singularity at x = 0 prevents this point from being a true equilibrium position. This raises critical questions: How can periodic solutions of the singular oscillator be explained intuitively? Is it physically rational for oscillations to occur around a position where the restoring force is undefined? This paper addresses these questions using simple mechanical analogies, such as a bouncing ball and the motion of a small object’s image in a mirror, to provide intuitive explanations of the periodic solutions. This analysis is particularly useful for teaching nonlinear phenomena at the university level and will assist young scientists with limited experience in the field.
High-temperature ultraviolet photodetector and amplifying integrated circuits based on AlGaN/GaN heterostructure
Authors: Tang Xi , Liu Xiaoyu , Zhao Chunyu , Niu Kui , Li Ziyun , Li Hui , Li Baikui , Wang Jiannong
Published: December 2024

In this work, an ultraviolet (UV) photodetection and amplifying integrated circuit (IC) based on an AlGaN/gallium nitride (GaN) heterostructure is demonstrated. The IC consists of a metal-heterostructure-metal photodetector (MHM-PD) and a high-electron-mobility transistor (HEMT)-based amplifier. The photoresponse of the MHM-PD increases at elevated temperatures due to the spatial separation of the photocarriers under the polarization electric field at the AlGaN/GaN heterointerface, as well as the photo-enhanced leakage current through the metal-heterostructure junction. At 250 °C, MHM-PD achieves a peak photoresponsivity of 14.5 A W−1 and a UV-to-visible rejection ratio of 104. As the thermal chuck temperature increases from 25 °C to 250 °C, the performance of the HEMT-based amplifier shows good thermal stability. Finally, the IC achieves a photoresponse of over 106 V W−1 and a switching frequency of 50 kHz at 250 °C with rise and decay time constants of 3.95 μs and 2.8 μs, respectively. These results show that the IC has a high-sensitivity and high-speed UV detection capability.
Influence of band occupation on electron-phonon coupling in gold
Authors: Held Tobias , Weber Sebastian T , Rethfeld Baerbel
Published: December 2024

Electron-phonon coupling is a fundamental process that governs the energy relaxation dynamics of solids excited by ultrafast laser pulses. It has been found to strongly depend on the electron temperature as well as on nonequilibrium effects. Recently, the effect of occupational nonequilibrium in noble metals, which outlasts the fully kinetic stage, has come into increased focus. In this study, we investigate the influence of nonequilibrium density distributions in gold on the electron-phonon coupling. We find a large effect on the coupling parameter which describes the energy exchange between electrons and phonons. Our results challenge the conventional view that electron temperature alone is a sufficient predictor of electron-phonon coupling.
Design, construction and validation of a magnetic particle imaging (MPI) system for human brain imaging
Authors: Mattingly Eli , Śliwiak Monika , Mason Erica , Chacon-Caldera Jorge , Barksdale Alex , Niebel Frauke H , Herb Konstantin , Graeser Matthias , Wald Lawrence L
Published: December 2024

Objective. Magnetic particle imaging (MPI) was introduced in 2005 as a promising, tracer-based medical imaging modality with the potential for high sensitivity and spatial resolution. Since then, numerous preclinical devices have been built but only a few human-scale devices, none of which targeted functional neuroimaging. In this work, we probe the challenges of scaling the technology to meet the needs of human functional neuroimaging with sufficient sensitivity for detecting the hemodynamic changes following brain activation with a spatio-temporal resolution comparable to current functional magnetic resonance imaging approaches. Approach. We built a human brain-scale MPI system using a mechanically-rotated, permanent-magnet-based field-free line (FFL) (

1.1

Tm

−
1

) with a water-cooled, 26 kHz drive coil producing a field of up to 7 mT

peak

, and receive coil that can fit over a human head. Images are acquired continuously at a temporal resolution of 5 s/image, controlled by in-house LabView-based acquisition software with online reconstruction. We used a dilution series to quantify the detection limit, a series of parallel-line phantoms to assess the spatial resolution, and a large ‘G’ shaped phantom to demonstrate the human-scale field of view (FOV). Main results. The imager has a sensitivity of about 1 µg

Fe

over a 2D imaging FOV of 181 mm diameter(132 pixels) in a 5 s image. Depending on the image reconstruction used, the spatial resolution defined by 50% contrast between adjacent lines was 5–7 mm. Significance. This proof-of-concept system demonstrates a pathway for human MPI functional neuroimaging with the potential for an order of magnitude increase of sensitivity compared to the other human hemodynamic imaging methods. It demonstrates the successful transition of the FFL based MPI architecture from the rodent to human scale and identifies areas which could benefit from further work.
Thin film photo(electro)catalysts for the generation of energetic vectors: success cases and challenges, a brief review
Authors: Alfaro Cruz M R , Luévano-Hipólito E , Garay-Rodríguez L F , Torres-Martínez Leticia M
Published: December 2024

Thin-film semiconductors are excellent candidates for converting solar energy into chemical energy via water splitting because of their outstanding physical and chemical properties. This review aims to provide the most recent findings on the production of energetic vectors from photo-(electro-)catalytic water splitting using thin-film semiconductors as catalysts. Recent successful cases are discussed to provide the scientific community with a guide for the design of new and advanced thin-film semiconductors with maximum efficiency for scaling the process. In addition, the use of coatings to provide a higher amount of catalyst for photo(electro)catalytic H2 production is discussed. Some of the most critical challenges in this reaction, such as charge recombination, light absorption, catalyst recovery, and stability, have been effectively addressed by applying thin films. In addition, the design of adequate thin-film photo(electro)chemical reactors is a critical step in improving efficiency and avoiding mass transfer limit steps. However, further research is required to provide continuous and low-cost manufacturing deposition techniques that favor optimal conditions to produce clean and renewable H2.
Ontology for smart 4D printed material systems and structures synergically applied with generative artificial intelligence for creativity promotion
Authors: Solórzano-Requejo William , Vega Carlos Aguilar , Martínez Rodrigo Zapata , Bodaghi Mahdi , Lantada Andrés Díaz
Published: December 2024

This study presents a versatile ontology for describing all kinds of smart or stimuli-responsive 4D printed material systems and structures. The different components of the ontology, namely: initial geometry and shape, shape-morphing principle(s), triggering stimuli, intermediate/final geometry and shape, 4D material and printing or additive manufacturing technology, are enumerated and classified. Accordingly, a codification system for schematically illustrating the actuation cycle of 4D printed material systems and structures, and shape-morphing devices in general, is proposed. The systematic application of the ontology to a relevant set of examples helps to demonstrate its utility and adaptability to many different types of 4D printed objects. It demonstrates that the ontology and codification schemes developed in this research can serve a comprehensive classification tool for the emergent field of 4D printing. It is the first ontology capable of representing the multiple actuation steps of complex 4D printed devices and actuators, in which several metamorphoses may be achievable, due to combinations of different shape-morphing principles and triggering stimuli. To this end, a single line of code is required. A glossary is provided to support its implementation and application. Besides, the usability of the ontology and related codification by a generative artificial intelligence (AI) for supporting engineering design tasks is explored and validated through a set of examples and an industrial use case. This work is expected to provide a universal language to facilitate the communication in the 4D materials and printing field, as well as a synergic generative AI-based methodology for creativity promotion linked to innovative smart 4D printed material systems and structures.
On the magnetic layer behind a shock wave
Authors: Núñez Manuel
Published: December 2024

The growth in temperature behind a shock wave generates a sharp increase in the fluid conductivity. In the presence of a possible background magnetic field originating in the obstacle forming the bow shock, this creates a Lorentz force which acts upon the flow. Since this enhanced conductivity in hypersonic flows is limited to a narrow layer behind the shock, where also the density increases markedly, one is able to use some reasonable approximations to analyze the magnetohydrodynamic equations associated to the flow. This is performed in the plane and axisymmetric cases, with eminently intuitive results: the transverse component of the magnetic field acts as a brake, while the longitudinal component presses the streamlines against the body or separates them from it. Details for poloidal and toroidal fields are quite different.
Variational principles of physics and the infinite Ramsey theory
Authors: Bormashenko Edward
Published: December 2024

Application of the Ramsey Infinite Theorem to the fundamental variational principles of physics is addressed. The Hamilton Least Action Principle states that, for a true/actual trajectory of a system, Hamilton’s Action is stationary for the paths, which evolve from the preset initial space-time point to the preset final space-time point. The Hamilton Principle distinguishes between the actual and trial/test trajectories of the system in the configurational space. This enables the transformation of the infinite set of points of the configurational space (available for the system) into the bi-colored, infinite, complete, graph, when the points of the configurational space are seen as the vertices, actual paths connecting the vertices/ points of the configurational space are colored with red; whereas, the trial links/paths are colored with green. Following the Ramsey Infinite Theorem, there exists the infinite, monochromatic sequence of the pathways/clique, which is completely made up of actual or virtual paths, linking the interim states of the system. The same procedure is applicable to the Maupertuis’s principle (classical and quantum), Hilbert-Einstein relativistic variational principle and reciprocal variational principles. Exemplifications of the Infinite Ramsey Theorem are addressed.
Fundamental vector soliton dynamics governed by Kerr and Raman nonlinearities in optical fiber
Authors: Ibarra-Villalon H E , Pottiez O , Gómez-Vieyra A , Lauterio-Cruz J P
Published: December 2024

This work analyzes numerically the propagation of a fundamental vector soliton in presence of a Raman soliton self-polarization shift (RSSPS) effect driven by the self- and cross-frequency shift that are induced by the stimulated Raman scattering (SRS), which is modeled by two coupled nonlinear Schrödinger equations in a circular polarization basis. Particularly, the propagation of the fundamental vector soliton, as a sech-squared temporal pulse profile, is also governed by a compensation balance between dispersion and Kerr effect. In this analysis, the numerical approach for solving the propagation problem is studied in detail. Additionally, for a better understanding of the vector soliton dynamics, the pulse propagation governed by linear and nonlinear effects, considering their individual contributions as well as their simultaneous interplay, are studied by spectrograms, which represent the temporal-spectral distribution of the pulse profile. As a result, the fundamental vector soliton, which maintains its temporal envelope over propagation, validates a temporal walk-off along propagation that is consistent with a redshifted spectral evolution; at the same time, the polarization evolution is correlated with this pulse dynamics.
Preparation and characterization of CuInSe2 (CIS) thin films by one-step electrodeposition: corrosion analysis
Authors: Akgüney Ali Can , Akdağ Adem , Demir Kübra Çınar
Published: December 2024

In this study, it was focused on the structural and morphological and the corrosion properties of CIS NTFs electrodeposited on ITO substrates before and after annealing. After deposition, the CIS NTFs were annealed for 30 min. at 400 °C in a nitrogen (N2) atmosphere. X-ray diffraction (XRD) analysis indicated that CIS NTFs crystallize in a tetragonal structure typical of the chalcopyrite phase, exhibiting a preferential orientation along the (112) plane and the CIS NTFs exhibited an increase in grain size after annealing. Raman analysis showed that the wavenumbers at 210 cm−1 and 288 cm−1 reveal the characteristic modes of the chalcopyrite phase of CIS after the annealing. The roughness of the CIS NTFs was measured at 108 nm before annealing, and this value increased after the annealing. The corrosion rate of the CIS NTFs was recorded at 6.04 × 10−4 mm y−1 before annealing and this value decreased after annealing. The findings indicate that the increase in grain size subsequently was attributed to improved corrosion resistance after annealing and the increase of the corrosion resistance performed the more protective layer in CIS NTFs after annealing.
A comparative hybrid-DFT study of energy-efficient halide perovskite under hydrostatic pressure
Authors: Shoaib Hassan Syed , Gillani S S A
Published: December 2024

To achieve the main goal of this research, follow these steps to perform a detailed computational analysis using the Heyd–Scuseria–Ernzerhof (HSE-03) hybrid functional. This analysis will cover the structural, electrical, elastic, mechanical, anisotropic, and optical properties of halide perovskite materials CsPbX3 (X = Cl, Br, and I) by applying pressure from 0 to 25 GPa. Under stress, all materials exhibit a consistent decrease in lattice parameters and a decrease in band gap up to 25 GPa. To explore the electronic band structure (BS), we have estimated the TDOS (Total Density of States) and EPDOS (Elemental Partial Density of States). To further assess the material's relevance, we calculated several optical properties including absorption I (ω), extinction coefficient k (ω), refractive index n (ω), loss function L (ω), reflectivity R (ω), the real part of the dielectric function

ε

1

(
ω
)

and the imaginary part

ε

2

(
ω
)

. The static values of reflectivity R (ω), the real part of the dielectric function

ε

1

(
ω
)

increase by applying pressure on all materials. With the pressure application, the peak of absorption peak under study perovskites shifts markedly towards higher photon energies. Moreover, its high refractive index, reflectivity, and absorption make it an important element for optoelectronic devices. The structure retains its cubic form and there is no change in phase in all three materials. The materials are stiff, unyielding, and mechanically stable demonstrating elevated resistance to shear stress based on different mechanical and elastic parameters, including Young’s modulus, bulk modulus, and shear modulus. The Pugh/Frantsevich ratios, Kleinman’s parameter, Cauchy pressure, and Poisson’s ratio, indicate the ductility of materials, metallic bonding characteristics, and resilience under high pressure. Additionally, distinctive anisotropy factors are used to confirm the material's anisotropic properties.
Simulation of Li-pellet triggered ELMs in EAST with an impurity model implemented under BOUT++ framework
Authors: Li Mao , Sun Zhen , Sun Jizhong , Chang Huayi , Xia Tianyang
Published: December 2024

A simple impurity model has been developed under the BOUT++ framework to investigate the Li-pellet triggered edge localized mode (ELM) in EAST configuration. The present impurity model decouples the ion pressure enhancement effect (IPEE) (which affects radial E

×

B flow shear and gyro-viscosity of deuterium ions and is implicitly included in our previous work) to make the simulation of Li pellet injection more physically reasonable. In addition, the present impurity model also includes the impurity equilibrium effect (IEE) (which induces modifications on vorticity and gyro-viscosity). The simulation results show that without IPEE a turbulent ELM induced by Li pellet is triggered by multiple peeling-ballooning modes (PBMs) rather than by a single dominant mode, and the simultaneous growth of multiple modes is conducive to reducing the time for pedestal entering the energy loss state. When a turbulent ELM occurs, the nonlinearly dominant modes undergo a secondary fast growth during fast crash phase. The finding explains the secondary increase of

D
α

emission observed in the DIII-D Li injection experiments. During the evolution of a turbulent ELM, the continuous pedestal collapse dominates the pedestal energy loss in turbulent transport phase; however, in saturation phase, the stabilizing effects on PBMs (n

≠

0) by n = 0 mode and radial E

×

B flow shear within the steepest gradient region are more prominent. It is also found that with IEE and without IPEE, the size threshold of ELM triggering and the magnitude of ELM sizes both show a good agreement with EAST and DIII-D experimental observations.
A HVSR inversion method based on the multi-modal forest optimization algorithm
Authors: Chen Xuanning , Han Fuxing , Gao Zhenghui , Sun Zhangqing , Han Jiangtao , Chen Changle , Zhou Yanwei , Li Gang
Published: December 2024

The exploration of urban underground spaces is of great significance to urban planning, geological disaster prevention, resource exploration, and environmental monitoring. However, due to severe interferences, conventional seismic methods cannot adapt to the complex urban environment well. Since adopting the single-node data acquisition method and taking the seismic ambient noise as the signal, the microtremor horizontal to vertical spectral ratio (HVSR) method can effectively avoid the strong interference problems caused by the complex urban environment, which could obtain information such as S-wave velocity and thickness of underground formations by fitting the microtremor HVSR curve. Nevertheless, HVSR curve inversion is a multi-parameter curve fitting process. Conventional inversion methods can easily converge to the local minimum, directly affecting the inversion results’ reliability. Thus, we propose a HVSR inversion method based on the multimodal forest optimization algorithm, which uses the efficient clustering technique and can locate the global optimum quickly. Tests on synthetic data show that the inversion results of the proposed method are consistent with the forward model. Both the adaption and stability to the abnormal layer velocity model are also demonstrated. The results of the real field data are also verified by the drilling information.
Research on improving power system stability with AC excitation VSPSH based on BPA
Authors: Wang Yingwei , Chen Lei , Yue Mingyi , Zhang Shunren , Zhang Guangqing , Gong Wenjun
Published: December 2024

In the process of achieving the “Dual Carbon” goals, there is an increasing integration of new energy sources into China’s power system, particularly the large-scale connection of wind power, which poses new challenges to the safe and stable operation of the grid. Compared to constant-speed pumped-storage hydropower units (CSPSH), variable-speed pumped-storage hydropower units (VSPSH) with adjustable speed characteristics demonstrate significant potential in the construction of a modernized power system. This paper constructs a three-machine-nine-node system model of a 300MW VSPSH with extensive wind power integration under the BPA environment. Through power disturbances and fault settings, the paper observes the enhancement of system stability after the integration of the VSPSH and evaluates the regulation effectiveness of the VSPSH.
A framework for demand response load forecasting based on federated learning
Authors: Zhang Pan , Chen Gang , Sun Lu , Wang Shujie
Published: December 2024

Addressing the scenario where distribution network operators predict load curves based on user data to participate in demand response, and to cope with issues such as user data privacy protection and the operators’ lack of permission to access metering data, this paper proposes a framework and method for demand response load forecasting based on federated learning. Focusing on features including weather, time, and users’ participation status in demand response, this approach utilizes horizontal federated learning technology to integrate data from various sources while safeguarding user data privacy. Furthermore, a balanced scheduling scheme for participating users and samples, along with data preprocessing, is integrated to enable effective discrimination of load curves. Case study analysis demonstrates that the proposed load forecasting method can maintain superior prediction performance while ensuring the privacy of user data.
Electromagnetic scattering characterization of a layered rough soil ground
Authors: Zhang Jiangong , Yu Pengcheng , Gan Zheyuan , Chen Yajie , Cao Xiaoyu , Zhao Zhibin , Jiao Chaoqun
Published: December 2024

As the density of additional ultra-high voltage alternating current and direct current transmission lines in China increases, so does the passive interference from transmission lines to various types of equipment. At present, the objective of previous studies is to examine the impact of passive interference on the performance of transmission lines, ignoring the impact of rough soil ground on the passive interference of transmission line. Put it another way, the earth as a pure conductor processing, the use of this simplified processing method of the results obtained from the measured value is often a large deviation. For this reason, this paper considers the added transmission line erected in the rough soil ground environment. A more realistic passive interference model for ultra-high voltage transmission lines developed. We are looking at how electromagnetic waves behave when they are transmitted through different types of rough soil. To do this, we have created a model of layered rough soil using the Monte Carlo method. Then, the scattering coefficients of layered rough soil ground at two stations are calculated by going to use the method of moments. In the end, the effects of roughness change and distance change of layered rough soil ground on the scattering coefficients are investigated, and a model of layered rough soil ground is established on the basis of single-layered rough ground to take a look at how electromagnetic waves behave when they hit layered, uneven soil.
Analysis of the influence of power supply on control and protection device for voltage source converter-based high voltage direct current
Authors: Huang Xionghui , Ren Chenglin , Cai Yongliang , Peng Maolan , Liu Tao , Xiao Hongyou
Published: December 2024

The high-frequency DC switching power supply is a core module in control and protection devices for voltage source converter-based high voltage direct current (VSC-HVDC) systems. In practice, this type of power supply is often prone to failure. This paper investigates the working circuit of the switching power supply and examines various quality issues with power supply components. It focuses on aluminum electrolytic capacitors and key circuit DC/DC converters, which are particularly failure-prone. The study establishes a model for these components and analyzes the effects of capacitance reduction and increased equivalent series resistance, which result from capacitor failures. Through simulation experiments, the research explores the impact of these quality issues on DC/DC circuits. This work lays the foundation for understanding how the power module affects the VSC-HVDC protection device.
A high resistance grounding fault identification method for distribution network considering topological connection
Authors: Deng Ming , Gao Yuan
Published: December 2024

Traditional high resistance grounding fault identification in distribution networks fails to meet load demands, demanding optimization for reliability and economics. A novel approach considers topological connections, applies the Hilbert-Huang transform for signal decomposition, refines components, and utilizes particle swarm optimization to enhance feature vectors. This defines an association matrix and leverages zero sequence current features, accurately pinpointing suspected high resistance ground faults through filtered second derivative concavity and zero crossing point analysis. Experimental data underscores the design method’s exceptional calculation efficiency, capping at 40 milliseconds, and maintaining over 90% fault recognition accuracy. Recognition time notably diminishes, shrinking from 0.91 seconds for 10 iterations to 0.28 seconds for 50 iterations.