bluuebunny/crossref_metadata_2025 huggingface dataset:
Anthropogenic Impacts on Amplified Midlatitude European Summer Warming and Rapid Increase of Heatwaves in Recent Decades
Authors: Yin Zejiang , Dong Buwen , Wei Wei , Yang Song
Published: August 2024

Midlatitude Europe (ME) emerges as a prominent heatwave hotspot with rapid increases in summer surface air temperature and heatwave days since 1979, surpassing the global land averages by approximately 2.6 and 2.3 times, respectively. The circulation analogs‐based dynamic adjustment reveals that approximately 38% and 35% of these trends result from shifts in zonal dipolar circulation patterns over the North Atlantic (NA) and Europe, crucial for the enhanced warming compared to the global land average. The circulation changes are associated with warming sea surface temperatures in the NA. This warming pattern resembles the Atlantic Multidecadal Variability and is predominantly induced by greenhouse gases. Moreover, the stronger air temperature response in ME to decreased aerosols amplifies warming, contributing to the rapid increase in heatwave frequency. These findings highlight a prominent influence of anthropogenic forcings on the swift surge of European heatwaves compared to global land, with a potential implication for adaptation strategies and risk management.
Stratospheric Quasi‐Biennial Oscillation Modulates the Impact of Boreal Summer Intraseasonal Oscillation on Rainfall Extremes in the Yangtze–Huaihe River Basin
Authors: Zhou Fang , Wu Yuqi , Han Tingting , Yin Zhicong
Published: August 2024

The impact of the boreal summer intraseasonal oscillation (BSISO) on rainfall anomalies in the Yangtze–Huaihe River Basin (YHRB) was found to be modulated by the stratospheric quasi‐biennial oscillation (QBO), which is reasonable for the close associations between the QBO and summer extreme precipitation in the YHRB. It was found that the extreme precipitation preferentially occurred in the YHRB during the easterly phase of the QBO (EQBO) compared to the westerly phase of the QBO (WQBO). This was primarily because the BSISO was more prone to cause rainfall extremes in the YHRB during the EQBO summers than during the WQBO summers. The EQBO can induce the background stratospheric easterly wind to arch downward into the troposphere, which enhanced the BSISO‐associated moisture transport and moisture convergence and thus resulted in stronger rainfall extremes in the YHRB.
Evidence for a Sea Level Fall During the Last Interglacial Highstand on West Caicos, Turks and Caicos Islands
Authors: Fouke Kyle W. , Kerans Charles
Published: August 2024

Reconstruction of ancient sea level during the Late Pleistocene Marine Isotope Stage 5e (MIS 5e), from ∼129 to 116 ka, has the potential to improve the accuracy of future global sea level projections by providing a key benchmark for model calibration during a past warm period. Shallow‐water carbonate exposures comprising the tectonically stable Bahamas and Turks and Caicos Islands contain a regional unconformity that suggests MIS 5e sea level variability. It is not yet fully understood whether this intra‐MIS 5e unconformity was formed under subaerial or submarine conditions. The current study applies next generation sedimentologic, stratigraphic and petrographic analyses across the intra‐MIS 5e erosional unconformity exposed at four locations on West Caicos to reconstruct the conditions in which it formed. The unconformity is characterized with field mapping and digital terrain models, combined with U‐Th coral dating from previous studies. Marine and meteoric diagenetic alteration events were determined by integrating field observations and high‐resolution brightfield and autofluorescence microscopy to compile a comprehensive paragenetic sequence of the intra‐MIS 5e unconformity. Results indicate the erosional unconformity coincided with a rapid 1–3 m sea level fall resulting in beveled in situ coral heads and spatially constrained meteoric diagenesis. Current models of solar insolation and global‐scale ice sheet dynamics currently do not predict an intra‐MIS 5e sea level fall or associated climatic fluctuations. Illuminating the magnitude and timing of an intra‐MIS 5e sea level fall will provide better constraints on numerical models that link ice sheet collapse and climate change.
Rainfall and Hydrograph Styles in Ephemeral Streams of the Drylands of Patagonia (South America–Argentina)
Authors: Kaless Gabriel , Malnero Héctor , Frumento Oscar , Pascual Miguel
Published: August 2024

Ephemeral streams in dry environments can convey high intensity sediment‐laden flash floods. The study of these events is quite difficult due to remote locations with limited accessibility, unexpected events, rough weather conditions and safety concerns. Hence combined data of rainfall and flood hydrograph is rather scarce in the world, and null in Patagonia‐South America. The Experimental Basin Arroyo Sagmata (total drained area of 129 km2), located in the Lower Valley of the Chubut River has been equipped with 4 rain gauges, and 4 time‐lapse cameras in four reaches of the arroyos. Data from a 4‐year monitoring provides valuable insights about the hydrological response of basins in the drylands of Patagonia, such as the time of response, the shape of hydrographs and its relation with the hyetographs. Four hydrograph styles have been observed: single‐peak (S), multi‐peaks (M), flat‐top (F) and compound (C) peaks. Rainfall styles have also been classified into single, multiple and compound. Soil processes operate reducing the number of peaks (M‐type hyetographs are transformed into S‐ or M‐type hydrographs). The rain structure is also important, especially when the high intensity occurs in the beginning of the event. Channel connectivity pattern and disconnections explain the observation of M‐type hydrograph and F‐type hydrograph, respectively.
Rejuvenation of BMSCs senescence by pharmacological enhancement of TFEB-mediated autophagy alleviates aged-related bone loss and extends lifespan in middle aged mice
Authors: Luo Ziwei , Wei Wanyi , Qiu Dawei , Su Zixia , Liu Liangpu , Zhou Honghai , Cui Hao , Yang Li
Published: August 2024

Bone marrow stromal/stem cells (BMSCs) are generally considered as common progenitors for both osteoblasts and adipocytes in the bone marrow, but show preferential differentiation into adipocytes rather than osteoblasts under aging, thus leading to senile osteoporosis. Accumulated evidences indicate that rejuvenation of BMSCs by autophagic enhancement delays bone aging. Here we synthetized and demonstrated a novel autophagy activator, CXM102 that could induce autophagy in aged BMSCs, resulting in rejuvenation and preferential differentiation into osteoblasts of BMSCs. Furthermore, CXM102 significantly stimulated bone anabolism, reduced marrow adipocytes, and delayed bone loss in middle-age male mice. Mechanistically, CXM102 promoted transcription factor EB (TFEB) nuclear translocation and favored osteoblasts formation both in vitro and in vivo. Moreover, CXM102 decreased serum levels of inflammation and reduced organ fibrosis, leading to a prolonger lifespan in male mice. Our results indicated that CXM102 could be used as an autophagy inducer to rejuvenate BMSCs and shed new lights on strategies for senile osteoporosis and healthyspan improvement.
Fast prediction of personalized abdominal organ doses from CT examinations by radiomics feature-based machine learning models
Authors: Shao Wencheng , Lin Xin , Zhao Wentao , Huang Ying , Qu Liangyong , Zhuo Weihai , Liu Haikuan
Published: August 2024

The X-rays emitted during CT scans can increase solid cancer risks by damaging DNA, with the risk tied to patient-specific organ doses. This study aims to establish a new method to predict patient specific abdominal organ doses from CT examinations using minimized computational resources at a fast speed. The CT data of 247 abdominal patients were selected and exported to the auto-segmentation software named DeepViewer to generate abdominal regions of interest (ROIs). Radiomics feature were extracted based on the selected CT data and ROIs. Reference organ doses were obtained by GPU-based Monte Carlo simulations. The support vector regression (SVR) model was trained based on the radiomics features and reference organ doses to predict abdominal organ doses from CT examinations. The prediction performance of the SVR model was tested and verified by changing the abdominal patients of the train and test sets randomly. For the abdominal organs, the maximal difference between the reference and the predicted dose was less than 1 mGy. For the body and bowel, the organ doses were predicted with a percentage error of less than 5.2%, and the coefficient of determination (R2) reached up to 0.9. For the left kidney, right kidney, liver, and spinal cord, the mean absolute percentage error ranged from 5.1 to 8.9%, and the R2values were more than 0.74. The SVR model could be trained to achieve accurate prediction of personalized abdominal organ doses in less than one second using a single CPU core.
Porous alumina nanosheet-supported asymmetric platinum clusters for efficient diboration of alkynes
Authors: Gao Yan , Geng Huilong , Ge Jinlong , Zhu Linlin , Sun Zhiyi , Deng Ziwei , Chen Wenxing
Published: August 2024

Precisely designing asymmetrical structures is an effective strategy to optimize the performance of metallic catalysts.
Metal-free negative linear compressibility (NLC) material – the cocrystal of 1,2-bis(4-pyridyl)ethane and fumaric acid
Authors: Patyk-Kaźmierczak Ewa , Kaźmierczak Michał
Published: August 2024

A cocrystal of 1,2-bis(4-pyridyl)ethane and fumaric acid with exceptional negative linear compressibility (NLC) behavior is proposed as a protoplast for metal-free environmentally friendly NLC materials.
Effect of dynamic bond concentration on the mechanical properties of vitrimers
Authors: Pandya Harsh , Khabaz Fardin
Published: August 2024

The presence of varying concentrations of dynamic linkages in hybrid vitrimer networks facilitates stress relaxation and delayed crazing while also improving creep resistance.
Construction of heterocycle-triazolotriazine framework energetic compounds: towards novel high-performance explosives
Authors: Yang Pengju , Zheng Xiaoxiao , Zhang Guojie , Lei Caijing , Cheng Guangbin , Yang Hongwei
Published: August 2024

In this paper, three neutral heterocycle-triazolotriazine compounds featuring multiple amino groups and nitro groups were designed and synthesized.
Dual role tertiary amines in photocatalytic cyclizations: towards sustainable syntheses of 1,3-dinitrogen heterocycles
Authors: Guo Fuhu , Zhu Junli , Fan Xinyuan
Published: August 2024

The overlooked holds significant worth: probing the typically neglected tertiary amine sacrificial additive reveals its dual role as an electron donor and methyl source, making it a valuable formaldehyde precursor.
Four-membered heterocyclic molecules featuring boron and heavy group 14 elements that exhibit both σ-aromatic and π-aromatic properties: a new synthetic target
Authors: Zhang Zheng-Feng , So Cheuk-Wai , Su Ming-Der
Published: August 2024

Theoretical findings demonstrate that the inorganic four-membered heterocyclic neutral molecules (B2G14G14′) display both σ-aromaticity and π-aromaticity.
Safety concerns in solid-state lithium batteries: from materials to devices
Authors: Luo Yang , Rao Zhonghao , Yang Xiaofei , Wang Changhong , Sun Xueliang , Li Xianfeng
Published: August 2024

The review focuses on potential safety issues in solid-state lithium batteries during electrolyte synthesis and battery operation/failure, and proposes recent innovations and future directions to inhibit thermal failure and hazardous product release.
Thermodynamically stable low-Na O3 cathode materials driven by intrinsically high ionic potential discrepancy
Authors: Li Meng , Zhuo Haoxiang , Xu Yang , Jing Qihang , Wu Yanlong , Gu Yang , Liao Zhou , Wang Kuan , Song Miao , Li Xiaona , Liang Jianwen , Zhao Changtai , Jiang Yingying , Wu Tianci , Geng Dongsheng , Hu Jiangtao , Sun Xueliang , Xiao Biwei
Published: August 2024

The difference in cationic potentials of the various elements in and between the transition metal layers is another essential factor to be taken into account to discriminate between the P/O types of layered materials.
Optical and molecular characteristics of urban wastewater dissolved organic matter: insights into their correlations
Authors: Chu Jiangyong , Liao Zhenliang
Published: August 2024

Urban domestic wastewater is a significant source of dissolved organic matter (DOM) in aquatic environments, critically impacting urban water quality.
Supramolecular control over the variability of color and fluorescence in low-molecular-weight glass
Authors: Zhang Yunfei , Cai Changyong , Li Fenfang , Tan Xin , Li Qing , Ni Xinlong , Dong Shengyi
Published: August 2024

The color and fluorescence of supramolecular glass were controlled by the non-covalent approach.
Strong, tough and environment-tolerant organohydrogels for flaw-insensitive strain sensing
Authors: Wang Yuqing , Liu Zhanqi , Liu Yuntao , Yan Jun , Wu Haidi , Zhang Hechuan , Li Huamin , Wang Junjie , Xue Huaiguo , Wang Ling , Shi Yongqian , Tang Longcheng , Song Pingan , Gao Jiefeng
Published: August 2024

Strong, transparent and anti-fatigue ionically conductive organohydrogels are prepared using a solvent exchange assisted hot-pressing method. The tensile strength and fatigue threshold of ICOHs can reach 36.12 MPa and 1212.86 J m−2, respectively.
Alcohol-gating femtosecond laser-induced micro/nano-structured membranes with reversible switching wettability and breathability
Authors: Pei Jiaqing , Yin Kai , Song Xinghao , Yang Pengyu , Wang Lingxiao , Huang Yin , Awan Saif Ullah , Khalil Ahmed S. G.
Published: August 2024

A reversible liquid gating membrane with the ability to regulate gas/liquid transport is critical for many fields, such as biological applications, multiphase separation, and sewerage treatment.
Inducing weak and negative Jahn–Teller distortions to alleviate structural deformations for stable sodium storage
Authors: Hou Zishan , Liu Yuanming , Yao Shuyun , Wang Shiyu , Ji Yingjie , Fu Weijie , Xie Jiangzhou , Yan Yi-Ming , Yang Zhiyu
Published: August 2024

KMMO induces weak and negative J–T distortions during electrochemical process. These two distortions mitigate the severe structural deformation caused by the strong J–T distortion, thereby improving the reversibility of Na+ storage performance.
Halogen regulation of multifunctional hybrid materials with photoluminescence and dielectric response
Authors: Liu Jiu-Yang , Zhu Ming , Zhang Feng-Wen , Ni Hao-Fei , Li Zhi-Long , Zhuang Bo , Ding Kun , Fu Da-Wei , Lu Hai-Feng , Lun Meng-Meng
Published: August 2024

Starting from the pivotal structure–performance relationship, three compounds are synthesized through halogen regulation, and the photoluminescence is dependent on the structure.
Conformationally enforced planarization of bis[1]benzothieno[1,4]thiazines: a rational design of redox-active fluorophores with increased radical cation stability
Authors: Hauer Simone T. , Kuhn Patrick , Pütz J. Maurice , Reiss Guido J. , Sorge Lukas P. , Ganter Christian , Heinze Katja , Müller Thomas J. J.
Published: August 2024

Rational design results in conformationally restricted bis[1]benzothieno[1,4]thiazines, being antiaromatic in the crystal with staircase-like packing. BBTTs form stable radical cations at low potentials and are strongly luminescent.
Recent advances in electrochemical difunctionalization of alkenes and alkynes for the synthesis of organohalides
Authors: Zheng Yu , Lu Wenguang , Chen Chunxi , Lu Yanju , Huang Shenlin
Published: August 2024

This review summarizes recent achievements in electrosynthesis of organohalides through difunctionalization of alkenes and alkynes and provides insights into future directions for the development of the field.
Glucospanlastics: innovative antioxidant and anticancer ascorbyl-2-glucoside vesicles for striking topical performance of repurposed itraconazole
Authors: Lamie Caroline , Elmowafy Enas , Attia Dalia , Mortada Nahed D.
Published: August 2024

Ascorbyl glucoside utilization in the preparation of innovative glucospanlastics loaded itraconazole for topical delivery.
Electrospun EVOH/AST-120 hybrid nanofiber membranes for removal of indoxyl sulfate from blood
Authors: Sasaki Makoto , Hirata Rieko , Konagai Ayano , Ebara Mitsuhiro
Published: August 2024

Nanofibers containing activated carbon using poly(ethylene-co-vinyl alcohol) (EVOH) were prepared to remove indoxyl sulfate (IS) from the blood.
A comprehensive review of production, applications, and the path to a sustainable energy future with hydrogen
Authors: Jumah Abdulrahman bin
Published: August 2024

Green hydrogen, a versatile and sustainable energy carrier, has garnered increasing attention as a critical element in the global transition to a low-carbon economy.
Design, synthesis, anticancer and in silico assessment of 8-caffeinyl chalcone hybrid conjugates
Authors: Soltani Rad Mohammad Navid , Behrouz Somayeh , Charbaghi Maedeh , Behrouz Marzieh , Zarenezhad Elham , Ghanbariasad Ali
Published: August 2024

Design, synthesis, anticancer, docking, and in silico assessment for 8-caffeinyl chalcone hybrid conjugates are reported. These compounds have potent activities against melanoma and breast cancer cell lines.
The interior of Uranus
Authors: Morf Luca , Müller Simon , Helled Ravit
Published: August 2024

We present improved empirical density profiles of Uranus and interpret them in terms of their temperature and composition using a new random algorithm. The algorithm to determine the temperature and composition is agnostic with respect to the temperature gradient in non-isentropic regions and chooses amongst all possible gradients randomly that are stable against convection and correspond to an Equation of State (EoS) compatible composition. Our empirical models are based on an efficient implementation of the Theory of Figures (ToF) up to tenth order including a proper treatment of the atmosphere. The accuracy of tenth order ToF enables us to present accurate calculations of the gravitational moments of Uranus up to J14: J6 = (5.3078 ± 0.3312) 10−7, J8 = (−1.1114 ± 0.1391) 10−8, J10 = (2.8616 ± 0.5466) 10−10, J12 = (−8.4684 ± 2.0889) 10−12, and J14 = (2.7508 ± 0.7944) 10−13. We consider two interior models of Uranus that differ with respect to the maximal number of materials allowed per layer of Uranus (three versus four composition components). The case with three materials does not allow Hydrogen and Helium (H-He) in deeper parts of Uranus and results in a higher water (H2O) abundance which leads to lower central temperatures. On the other hand, the models with four materials allow H-He to be mixed into the deeper interior and lead to rock-dominated solutions. We find that these four composition components’ models are less reliable due to the underlying empirical models’ incompatibility with realistic Brunt frequencies. Most of our models are found to be either purely convective with the exception of boundary layers, or only convective in the outermost region above ~80% of the planets’ radius rU. Almost all of our models possess a region ranging between ~(0.75–0.9) rU that is convective and consists of ionic H2O which could explain the generation of Uranus’ magnetic field.
Episodic mass loss in the very luminous red supergiant [W60] B90 in the Large Magellanic Cloud
Authors: Munoz-Sanchez G. , de Wit S. , Bonanos A. Z. , Antoniadis K. , Boutsia K. , Boumis P. , Christodoulou E. , Kalitsounaki M. , Udalski A.
Published: August 2024

Context. Despite mounting evidence that extreme red supergiants (RSGs) undergo episodic mass-loss events, their role in RSG evolution remains uncertain. Critical questions remain unanswered, such as whether or not these events can strip the star, and their timescale and frequency.

Aims. This study delves into [W60] B90, one of the most luminous and extreme RSGs in the Large Magellanic Cloud (LMC), with our aim being to search for evidence of episodic mass loss. Our discovery of a bar-like nebular structure at 1 pc, which is reminiscent of the bar around Betelgeuse, raised the question of whether [W60] B90 also has a bow shock, motivating the present study.

Methods. We collected and analyzed proper motion data from Gaia, as well as new multi-epoch spectroscopic and imaging data, and archival time-series photometry in the optical and mid-infrared (MIR). We used MARCS models to derive the physical properties of the star from the spectra.

Results. We find [W60] B90 to be a walkaway star, with a supersonic peculiar velocity in the direction of the bar. We detect shocked emission between the bar and the star, based on the [S II]/Hα > 0.4 criterion, providing strong evidence for a bow shock. The 30 yr optical light curve reveals semi-regular variability, showing three similar dimming events with ΔV ~ 1 mag, a recurrence of ~12 yr, and a rise time of 400 days. We find the MIR light curve to vary by 0.51 mag and 0.37 mag in the WISE1 and WISE2 bands, respectively, and by 0.42 mag and 0.25 mag during the last dimming event. During this event, optical spectroscopy reveals spectral variability (M3 I to M4 I), a correlation between the Teff and the brightness, increased extinction, and, after the minimum, spectral features incompatible with the models. We also find a difference of >300 K between the Teff measured from the TiO bands in the optical and the atomic lines from our J-band spectroscopy.

Conclusions. [W60] B90 is a more massive analog of Betelgeuse in the LMC and therefore the first single extragalactic RSG with a suspected bow shock. Its high luminosity of log(L/L⊙) = 5.32 dex, mass-loss rate, and MIR variability compared to other RSGs in the LMC indicate that it is in an unstable evolutionary state, undergoing episodes of mass loss. Investigating other luminous and extreme RSGs in low-metallicity environments using both archival photometry and spectroscopy is crucial to understanding the mechanism driving episodic mass loss in extreme RSGs in light of the Humphreys-Davidson limit and the “RSG problem”.
First-principles computation of hydrides-perovskites XZrH3 (X = Ba, Ca, and Sr): evaluation of structural, electronic, optical and mechanical properties for hydrogen storage
Authors: Jawad Muhammad Ajmal , Gillani Syed Sajid Ali
Published: August 2024

In the current study, the physicochemical properties of the hydride perovskite XZrH3 (X = Ba, Ca, and Sr) are thoroughly investigated using first-principles calculations. Structural calculations indicate that the BaZrH3, CaZrH3, and SrCuH3, with lattice values of 4.27, 4.01, and 4.12, are synthesizable and thermodynamically stable. The density of states (DOS) and electronic band structure analysis of XZrH3 (X = Ba, Ca, and Sr) perovskites reveal metallic behavior. Apart from that, simulations were performed for the refractive index, reflectivity, dielectric function, and energy-loss functions. The shear and Young's moduli, as well as the Poisson's ratio, are calculated for novel polycrystalline materials, and the results proved that compounds with the formula XZrH3 (X = Ba, Ca, and Sr) are ductile. The analysis of the hydrogen storage features of the BaZrH3, CaZrH3, and SrZrH3 has revealed that they have gravimetric hydrogen storage capacities of 1.307 wt%, 2.251 wt%, and 1.662 wt%, respectively. Overall, the results offer a feasible strategy for creating novel, potentially beneficial perovskite-type hydrides for hydrogen storage.
Wirbelkörperfrakturen bei Osteoporose
Authors: Heyde Christoph-Eckhard , Pieroh Philipp , Osterhoff Georg
Published: August 2024

Osteoporotische Frakturen der Wirbelsäule stellen eine zunehmende Herausforderung
dar. Heute verfügbare Klassifikationssysteme helfen zusammen mit Scores, welche
die individuellen Gegebenheiten der Betroffenen berücksichtigen, das
therapeutische Vorgehen individuell anzupassen. In diesem Beitrag werden
Hinweise zur diagnostischen Vorgehensweise, den konservativen und operativen
Therapiemöglichkeiten und zu den Besonderheiten von Wirbelfrakturen bei
Osteoporose gegeben.
A Structured Social Media Health Support Program after Bariatric Surgery
Authors: Tamir Orly , Kais Hassan , Accos-Carmel Moran , Kolobov Tatyana , Matthews Gideon , Lipsits Aviva , Shalev Yuval , Sheffer-Benton Sigal , Benis Arriel
Published: August 2024

Background Social media networks have been found to provide emotional, instrumental, and social support, which may contribute to improved adherence to postbariatric surgery care recommendations.

Objectives This study aimed to evaluate the impact of an online social media-based, health care professional-led, educational and support program on patients' long-term engagement with and adherence to follow-up guidelines, self-care recommendations, and weight management after bariatric surgery.

Methods An observational cohort study, employing mixed methods, accompanied a 12-week interactive, structured, social media psychoeducational intervention program delivered on Facebook. Program participants, who had undergone one bariatric surgery within the past 1 to 7 years and were at least 18 years old at the time of surgery, were invited to join the program via posts online. Interested individuals were provided information about the program and the accompanying evaluation study, and those who met requirements completed study questionnaires before and after the program. Questionnaires included demographic and anthropometric information; postoperative recommendations received and their clarity and implementation; attitudes toward recommendation adherence; and well-being. Daily system data on program engagement were collected from the Facebook website.

Results Of the 214 participants enrolled in the program, 101 (80.2% female, mean age 43.8 ± 9.1 years and mean body mass index 30.2 ± 6.8 kg/m2, 1–7 years after bariatric surgery) completed both baseline and end-of-program questionnaires and were included in the analysis. Following the program, improvements were observed in most aspects of participants' adherence to postoperative recommendations and well-being. Close to half of the participants (44.6%) reported reaching their postoperative target weight at the end of the program or maintaining it throughout the program. Video posts drew higher participant engagement than other media, and content about proteins received the highest number of reactions. However, participants' active engagement gradually declined over time.

Conclusion Interactive health support on social media can positively enhance patient engagement, adherence to treatment recommendations, health outcomes, and overall well-being.
On the importance of separators as sites of 3D magnetic reconnection
Authors: Parnell C. E.
Published: August 2024

For 3D magnetic reconnection to occur there must exist a volume within which the electric field component parallel to the magnetic field is non-zero. In numerical experiments, locations of non-zero parallel electric field indicate sites of 3D magnetic reconnection. If these experiments contain all types of topological feature (null points, separatrix surfaces, spines and separators), then comparing topological features with the reconnection sites reveals that all the reconnection sites are threaded by separators with the local maxima/minima of the integrated parallel electric along fieldlines coinciding with these separators. However, not all separators thread a reconnection site. Furthermore, there are different types of separator. Cluster separators are short arising within an individual weak magnetic field region and have little parallel electric field along them so are not associated with much reconnection. Intercluster separators connect a positive null point lying in one weak-field region to a negative null point that lies in a different weak-field region. Intercluster separators often thread enhanced regions of parallel electric field and are long. Since separators form the boundary between four globally significant topologically distinct domains, they are important sites of reconnection, which can result in the global restructuring of the magnetic field. By considering kinematic bifurcation models in which separators form, it is possible to understand the formation of cluster and intercluster separators and explain their key properties.
Piezoelectric-based large-angle stroke fast steering mirror with high ratio of output range to resolution and self-sensing capability
Authors: Han Wenwen , Zhai Chongpu , Shao Shubao , Tian Zheng , Lu Qian , Zhang Shuwen , Xu Minglong
Published: August 2024

In space optical applications, the piezoelectric-actuated fast steering mirror (FSM) is one of the pivotal components for high-precision beam capturing and trajectory tracking. The FSM is restrained in small-angle scanning applications due to the short actuation stroke of the incorporated piezoelectric materials. This study introduces a dual-axis sub-radian stroke FSM with a high ratio of output range to resolution and self-sensing capability, based on cascading structures for displacement amplification and flexible parts for feedback. Theoretical analyses and finite element analysis (FEA) are applied to elucidate the driving and deformation mechanisms of the proposed FSM structure. To ensure the performance of the proposed FSM, the double-loop control strategies are implemented independently for rotation around the two orthogonal axes. Experimental results reveal that both axes can rotate 148.67 mrad under the closed-loop control, with the ratio of output range to resolution larger than 3.90 × 104, superior to existing FSMs. We further demonstrate with designed experiments of tracking complex trajectories that the relative tracking accuracy error remains lower than 0.02%.
Thermodynamic property derivatives of the electronic and static dielectric constants: A simple Grüneisen parameter approach
Authors: Brewer Chance , Jones John G. , Putnam Shawn A.
Published: August 2024

Recent developments in materials manufacturing has allowed researchers to engineer unique wave-matter interactions at the nano-scale. These interactions foster unique and coupled modes of thermal, optical, electrical, and acoustic energy transport and conversion. This study addresses the sensitivity of the static ϵ0 and complex ϵ~(ω)=ϵ1(ω)+iϵ2(ω) dielectric constant due to changes in pressure (P), volume (V), and temperature (T). General β-sensistivity relations are derived based on traditional Drude and Lorentz oscillator models. Then, these sensitivity relations are compared to literature dln⁡ϵi/dT and dln⁡ϵi/dln⁡V data for various metals, dielectric insulators, and semiconductor materials. For example, the effects of isotropic strain on ϵ(ω) are found to have two common contributions: the frequency dependence of the dielectric dispersion (dln⁡ϵ/dln⁡ω) and key vibrational-mode Grüneisen parameters (γi=−dln⁡ωi/dln⁡V). Because these sensitivity relations are dictated by the various electronic, optical, and lattice Grüneisen parameters, a comprehensive listing of mode Grüneisen parameters and coupled property data are provided for materials ranging from metals to semiconductors to polymers to dielectric insulators such as BaTiO3. In most cases, the developed sensitivity relations are consistent with published isotropic strain derivative data.
Validity of the constant relaxation time approximation in topological insulator: Sn-BSTS a case study
Authors: Hattori Yuya , Konoike Takako , Uji Shinya , Tokumoto Yuki , Edagawa Keiichi , Terashima Taichi
Published: August 2024

Gate-voltage dependent quantum oscillations in topological insulator Sn0.02Bi1.08Sb0.9Te2S (Sn-BSTS) are analyzed on the basis of the Lifshitz−Kosevich theory. The angular dependence of the quantum oscillations and Landau-level fan diagram analysis show that the quantum oscillations originate from topological surface states with the Berry phase of π. Gate-voltage control allows precise control of the Fermi energy, and a very weak energy dependence of the relaxation time τ of the topological surface states is revealed. By a simple algebraic argument using the linear response theory, it is shown that the weak energy dependence of τ validates the constant relaxation time approximation [τE,T=τ0] in the calculation of the Seebeck coefficient S and zTel=σS2T/κel.
Magnetic-field coils for metastability-exchange optical pumping, spectroscopy, and magnetic resonance of helium
Authors: Nacher Pierre-Jean
Published: August 2024

Optical pumping on the 23S–23P transition (1083 nm) of metastable 3He or 4He atoms is used for science and applications. Gas is usually enclosed in elongated cells with lengths ranging from several centimeters to several meters for efficient absorption. Good magnetic-field homogeneity is needed for weak diffusion-induced relaxation and long nuclear magnetic resonance (NMR) signal lifetimes. A compact coil system is designed using a target-oriented numerical optimization method. It provides a suitably uniform field over cell volumes, with characteristics depending on the chosen optimization parameters. Additional pairs of coils can be used to generate transverse field components with contributions to the total field inhomogeneities that are discussed.
Analysis of three-dimensional time-varying characteristics of subsonic plasma jet
Authors: Ding Fei , Liu Yanming , Jia Jing , Li Yixuan , He Leiqin , Deng Weifeng
Published: August 2024

The plasma jet wind tunnel, as a ground simulation device for studying the electromagnetic properties of near-space vehicle sheaths, can help people conduct several studies, such as communications and electronic parameter diagnostics. The plasma produced by a plasma generator has time-dependent variations due to the influence of power supply oscillations, turbulence, and other aspects of the device. To accurately define the experimental state of plasma, it is necessary to carefully analyze the three-dimensional (3D) time-varying characteristics of the plasma jet accurately since the distribution is non-uniform. This paper uses volume tomography technology to reconstruct the time series of the 3D emission field of the plasma jet with high-speed cameras. Then, the time–frequency characteristics, overall instability of the emission intensity, central axis position, and shape of the plasma jet are analyzed. The following characteristics are mainly observed: First, the plasma generator ejects plasma intermittently, which then spirals forward away from the nozzle. Second, the intensity, the radius of central axis movement, and the shape of the plasma jet vary with time at the same low frequency. The magnitude of this frequency is mainly related to the rate of change of the jet's air pressure difference with the vacuum chamber. Third, the overall instability of the plasma jet increases along the axial direction away from the nozzle and radially away from the center of the jet.
Flow-induced defects during metal injection molding: Role of powder morphology
Authors: Sanetrnik Daniel , Hausnerova Berenika , Ponizil Petr , Novak Martin , Monkova Katarina
Published: August 2024

Owing to the quality issues of highly filled compounds used in metal injection molding, the current research is focused on intercepting flow-induced inhomogeneities in multiphase compounds resulting from the segregation of metal powder particles from (typically) three/four-component polymer binders, resulting in an unacceptable porosity of the final sintered metal parts. A recently developed nondestructive approach for quantifying the extent of these flow-induced defects was employed to study the effect of the size and shape of water- and gas-atomized 17-4PH stainless steel powders on segregation. This method combines scanning electron microscopy/energy dispersive x-ray spectroscopy with an in-house analytical tool. The results show a higher tendency of coarser particles (D50 of 20 μm) for flow-induced defects, while an irregular shape (water-atomized particles) reduces this unwanted phenomenon.
Robust giant anomalous Nernst effect in polycrystalline nodal web ferromagnets
Authors: Wang Yangming , Sakai Akito , Minami Susumu , Gu Hao , Chen Taishi , Feng Zili , Nishio-Hamane Daisuke , Nakatsuji Satoru
Published: August 2024

The transverse thermoelectric effect based on the anomalous Nernst effect (ANE) has attracted attention, especially for thermoelectric and spintronic applications. Fe3X (X = Ga, Al) is known to exhibit a large ANE at room temperature owing to the topological electronic band structure so-called nodal web. Here, we systematically investigate ANE in the polycrystalline Fe3Ga1−xAlx and Fe3Al1−xSix. Despite significant chemical substitutions, a very robust feature of the large ANE −Syx∼ 5.7 μ V/K is found for Fe3Ga1−xAlx (0≲x≲0.6), exhibiting a striking x independent nodal web contribution. Since aluminum is more low-cost and abundant than gallium, our results indicate Fe3Ga1−xAlx (x∼0.6) should be suitable for large-scale thermoelectric applications.
Superconductor based, tomographic, neutron diagnostics for fusion power monitoring
Authors: Brock Mette Bybjerg , Chambon Amalia , Bahl Christian R. H. , Pietropaolo Antonino , Walsh Michael , Korsholm Søren Bang , Wulff Anders C.
Published: August 2024

We propose a scalable system of compact, superconducting neutron monitors, which can be embedded in any existing cryogenic infrastructure of a fusion system. The pixel-based nature of the detectors allows them to be placed at intervals following the circumference of a cooled zone, e.g., a field coil, thus allowing for a tomographic measurement of the neutron flux surrounding the plasma. An early stage prototype of the superconducting bolometer is described, and the key results of a previous feasibility study of this prototype performed with cold neutrons are summarized. The bolometer can be adapted for use with fast neutrons by altering the composition and geometry of the neutron-to-heat conversion layer. This paper describes the initial feasibility considerations for implementation in a superconducting tokamak. The sensor is based on a high-temperature superconductor, making it possible to select the operation temperature in the range 1–90 K. Neutron flux numbers were found using the ITER MCNP reference model, and these were embedded in a TOPAS model to find the expected signal measured by the bolometer at the position of a toroidal field coil. The results at the coil position indicate suitable operation levels in terms of the magnitude of the measured signal, with a measurable signal of several ohm, which is much smaller than the saturation energy of the detector. Radiation hardness is estimated and found to be on the order of at least 40 years for the relevant radiation levels. The upcoming investigation activities of the project are described for both radiation testing and analytical modeling.
Supersonic turbulent boundary layer on a plate. III. Laws of the wall for velocity and temperature
Authors: Vigdorovich Igor
Published: August 2024

We develop an asymptotic theory of compressible turbulent boundary layers on a flat plate, in which the mean velocity and temperature profiles can be obtained as exact asymptotic solutions of the boundary-layer and energy equations, which are closed using functional relations of a general form connecting the turbulent shear stress and turbulent enthalpy flux to mean velocity and enthalpy gradients. The laws of the wall for velocity and temperature are constructed in the form of expansions in a small parameter that is proportional to the Mach number formed with the friction velocity and the speed of sound on the wall. The leading term of the expansion for velocity coincides with the Van Driest formula; however, the law of the wall also contains a term of order one, the presence of which explains the discrepancy between the Van Driest formula and experimental and calculated data. The formulation of the law of the wall for temperature takes into account the fact that in the case of a cooled wall, the temperature varies non-monotonically across the boundary layer and has a local maximum in the logarithmic sublayer. Along with the constants known for incompressible flow, the theory contains three new universal constants, which are determined from a comparison with direct numerical simulation data for velocity and temperature.
Multi-objective optimization on blade airfoil of vertical axis wind turbine
Authors: Zhang Ruiyi , Li Deyou , Chang Hong , Wei Xuntong , Wang Hongjie
Published: August 2024

Vertical axis wind turbines (VAWTs) have garnered significant attention due to their omnidirectionality, low noise, suitability for turbulent conditions, and high efficiency in offshore cluster deployments. VAWTs are more sensitive to dynamic stall, which can lead to reduced performance and reliability. Selecting appropriate blade airfoils can enhance both performance and reliability. This study employs a parametric method to design 12 input parameters for controlling the blade airfoil, with the average power coefficient of a single vertical wind turbine blade and the coefficient of variation of the main shaft as output parameters. The Non-dominated Sorting Genetic Algorithm II multi-objective genetic algorithm is used for blade airfoil optimization, selecting the two best-performing airfoils from the Pareto front. The average power coefficient of a single blade increased by 8.6% and 4.3%, respectively, while the coefficient of variation decreased by up to 6.7% and 5.3%. The analysis of the blades at different azimuth angles indicates that optimized blades can suppress flow separation at high angles of attack, enable faster wake recovery, and reduce energy loss.
Effect of over-pressure on the dynamics of interacting cavitation bubbles near curved surfaces in sub-cooled liquid nitrogen
Authors: Mishra Arpit , Garva Arjun , Roy Arnab , Lakkaraju Rajaram , Ghosh Parthasarathi
Published: August 2024

In this study, we conduct direct numerical simulations to investigate the dynamics of interacting cavitation bubbles near a curved surface in liquid nitrogen, which serves as the surrounding fluid medium. Our simulations are carried out under both atmospheric and over-pressurized conditions, spanning pressures from 40 to 200 kPa above atmospheric pressure. We analyze the effects of over-pressure on bubble morphologies, oscillation periods, and the velocity of liquid micro-jets. Additionally, we briefly explore the shearing action of high-speed micro-jets as a means of material fragmentation for generating micro/nanoparticles in cryogenic environments. Finally, we propose a novel eco-friendly and sustainable approach for plastic waste recycling using cryo-comminution. We anticipate that our findings will contribute to an enhanced understanding of cavitation dynamics at cryogenic temperatures, with potential implications for both mitigating detrimental effects and harnessing cavitation for various applications.
The symmetry in asymmetric post-impact behaviors of droplets impacting on the inclined and moving surfaces
Authors: Yu Wenlong , Wang Wenhao , Yu Zhiyuan , Cao Damin , Wang Yifei , Chen Shuo , Zhao Jiayi
Published: August 2024

The asymmetric post-impact behaviors of droplets impacting on the inclined or moving surface are ubiquitous, which is important to various corresponding applications in biology, sustainability, and engineering. This asymmetry arises from the synergy between normal and tangential momentum with respect to the inclination or surface velocity, which is generally investigated in previous research separately. The present paper experimentally and theoretically demonstrates that the post-impact behaviors on the inclined or moving surface can be integrated into a universal system. Redefining the characteristic velocity ΔV, the morphology, spreading and height coefficient, and contact time of the droplet have been proved. Finally, the scaling laws of previous studies for the maximum spreading coefficient and the increment of the translational velocity are extended into a generalized frame, both feasible to inclined and moving surfaces. The work enhances comprehension and offers guidelines for more effective manipulation of the asymmetric post-impact behaviors exhibited by droplets upon impact.
Controlled growth of asymmetric chiral TeOx for broad-spectrum, high-responsivity and polarization-sensitive photodetection
Authors: Zhang Baihui , Ao Zhikang , Zhang Fen , Zhong Jiang , Zhang Shunhui , Liu Hang , Chen Yinghao , Xie Jianing , Wen Wenkui , Wang Guang , Chen Peng , Yang Xiangdong , Cao Jinhui , Zhong Mianzeng , Li Hongjian , Zhang Zhengwei
Published: August 2024

Low-dimensional nanostructures, especially one-dimensional materials, exhibit remarkable anisotropic characteristics due to their low symmetry, making them promising candidates for polarization-sensitive photodetection. Here, we present a chemical vapor deposition synthesis method for tellurium suboxide (TeOx), confirming the practicality of photodetectors constructed from TeOx nanowires (NWs) in high-responsivity, broadband, and polarization-sensitive detection. By precisely controlling the thermodynamics and kinetics of TeOx NWs growth, we achieve large-scale growth of TeOx NWs with highly controllable dimensions and propose a method to induce intrinsic built-in strain in TeOx NWs. Photodetectors based on quasi-one-dimensional TeOx NWs with ohmic contact demonstrate broadband spectral response (638–1550 nm), high responsivity (13 700 mA·W−1), and superior air stability. Particularly, owing to the inherent structural anisotropy of the photodetectors, they exhibit polarization-sensitive photodetection, with anisotropy ratios of 1.70 and 1.71 at 638 and 808 nm, respectively.
Instability of odd viscosity falling liquid films with insoluble surfactants
Authors: Yang Jingyang , Du Shaofeng , Xiao Yue , Wang Shaowei , Zhao Moli , Xiong QingRong
Published: August 2024

The linear and weakly nonlinear stability of odd viscosity film with insoluble surfactants flowing down an inclined plane under a normal electric field is investigated analytically. Using the long-wave expansion method, the nonlinear evolution equations for liquid film thickness and surfactant concentration are derived. Through the normal mode analysis, the effects of surface surfactant, odd viscosity, and electric field on the neutral stability curve and the temporal growth rates are calculated to explore the linear stability of the film. Two modes, i.e., Kapitza mode and surfactant mode, are identified. Linear results show that the presence of surfactants and odd viscosity has a stabilizing effect, while electric field has a destabilizing effect on flowing of thin film. Based on the Ginsburg–Landau equation, the primary bifurcations in the phase diagram for two types of modes are investigated. The results reveal the destabilizing nature with increasing Marangoni number and viscosity ratio for surfactant mode and the stabilizing nature for Kapitza mode.