bluuebunny/crossref_metadata_2025 huggingface dataset:
The aspherical explosions of the 03fg-like Type Ia supernovae 2021zny and 2022ilv revealed by polarimetry
Authors: Nagao T. , Maeda K. , Mattila S. , Kuncarayakti H. , Gutiérrez C. P. , Cikota A.
Published: July 2024

Context. A peculiar subtype of Type Ia supernovae (SNe), 03fg-like (super-Chandrasekhar) SNe, show different observational properties from prototypical Type Ia SNe: they typically have high luminosities at the light-curve peak, low expansion velocities, and strong carbon features. The origin of this class of Type Ia SNe has been actively debated. Recent nebular-phase infrared observations of the 03fg-like Type Ia SN 2022pul using the James Webb Space Telescope revealed large-scale asymmetries in the ejecta and the presence of the strong [Ne II] line at 12.81 μm, suggesting a violent merger of two white dwarfs as its origin.

Aims. Polarimetry is another powerful tool for studying the overall ejecta asymmetries of spatially unresolved SNe. Here, we aim to check the universality of the violent merger scenario as the origin of 03fg-like Type Ia SNe, by studying their explosion geometries using polarimetry.

Methods. In this Letter we present imaging-polarimetric observations of the two 03fg-like Type Ia SNe 2021zny and 2022ilv.

Results. SNe 2021zny and 2022ilv show high intrinsic polarization (∼1%–∼2%), which might be composed of multiple components with different polarization angles. This indicates that they have complex aspherical structures in their ejecta, supporting the violent merger scenario for their origin. Our observations provide the first clear evidence from polarimetry for such aspherical structures.
Discrepancies between spectroscopy and HST photometry in tagging multiple stellar populations in 22 globular clusters
Authors: Carretta Eugenio , Bragaglia Angela
Published: July 2024

Multiple populations (MPs) in globular clusters (GCs) are stars that are distinct for their abundances of light elements. The MPs can be directly separated by measuring abundances of C, N, O, Na, Al, and Mg with spectroscopy or indirectly from photometric sequences created by the impact of different chemistry on band passes of particular filters, such as the HST pseudo-colours in the ultraviolet. An attempt to link HST pseudo-colour maps (PCMs) and spectroscopy was made by Marino et al. (2019, MNRAS, 487, 3815), using abundances mostly from our FLAMES survey. However, we found that an incomplete census of stars in common was used in their population tagging. We corrected the situation by building our own PCMs and matching them with our abundances in 20 GCs, plus two GCs from other sources, doubling the sample with spectroscopic abundances available. We found that the pseudo-colour (magF275W − 2 × magF336W + magF438) does not have a monotonic trend with Na abundances, enhanced by proton-capture reactions in MPs. Moreover, on average about 16% of stars with spectroscopic Na abundances show a discrepant tagging of MPs with respect to the HST photometry. Stars with second generation (SG) chemistry are mistaken for first generation (FG) objects according to HST photometry and vice versa. In general, photometric indices tend to overestimate the fraction of FG stars, in particular in low mass GCs. We offer a simple explanation for these findings. Finally, we publish all our PCMs (with more than 31 800 stars in 22 GCs) with star ID and coordinates; this is done to ensure easy verification and reproduction, as should be the case in scientific papers.
Shocks in the warm neutral medium
Authors: Godard B. , Pineau des Forêts G. , La Porte J. , Merlin-Weck M.
Published: July 2024

Aims. Ultraviolet lines of neutral carbon observed in absorption in the local diffuse interstellar medium (ISM) have long revealed that a substantial fraction of the mass of the gas lies at a thermal pressure one to three orders of magnitude above that of the bulk of the ISM. In this paper, we propose that this enigmatic component originates from shocks propagating at intermediate (VS > 30 km s−1) and high velocities (VS ⩾ 100 km s−1) in the warm neutral medium (WNM).

Methods. Shock waves irradiated by the standard interstellar radiation field (ISRF) are modelled using the Paris-Durham shock code designed to follow the dynamical, thermal, and chemical evolutions of shocks with velocities up to 500 km s−1. Each observed line of sight is decomposed into a high-pressure component and a low-pressure component. The column density of carbon at high pressure is confronted with the model predictions to derive the number of shocks along the line of sight and their total dissipation rate.

Results. Phase transition shocks spontaneously lead to the presence of high-pressure gas in the diffuse ISM and are found to naturally produce neutral carbon with excitation conditions and line widths in remarkable agreement with the observations. The amounts of neutral carbon at high pressure detected over a sample of 89 lines of sight imply a dissipation rate of mechanical energy with a median of ~3 × 10−25 erg cm−3 s−1 and a dispersion of about a factor of three. This distribution of the dissipation rate weakly depends on the detailed characteristics of shocks as long as they propagate at velocities between 30 and 200 km s−1 in a medium with a pre-shock density of nH0 ⩾ cm−cm and a transverse magnetic field of B0 ⩽ 3 μG. We not only show that this solution is consistent with a scenario of shocks driven by supernova remnants (SNRs) but also that this scenario is in fact unavoidable. Any line of sight in the observational sample is bound to intercept SNRs, which are mostly distributed in the spiral arms of the Milky Way and expanding in the diffuse ionised and neutral phases of the Galaxy. Surprisingly, the range of dissipation rate derived here, in events that probably drive turbulence in the WNM, is found to be comparable to the distribution of the kinetic energy transfer rate of the turbulent cascade derived from the observations of CO in the cold neutral medium (CNM).

Conclusions. This work reveals a possible direct tracer of the mechanisms by which mechanical energy is injected into the ISM. It also suggests that a still unknown connection exists between the amount of energy dissipated during the injection process in the WNM and that used to feed interstellar turbulence and the turbulent cascade observed in the CNM.
RETRACTED: Farm typology analysis in Russian regions with different small entrepreneurship development level
Authors: Ukolova Anna , Ulianckin Alexandr
Published: July 2024

See the retraction notice BIO Web of Conferences 116, 00001 (2024), https://doi.org/10.1051/bioconf/202411600001
RETRACTED: Comparison of functional indices of hemostasis of cows and calves obtained taking into account body temperature
Authors: Tkacheva Elena , Fomina Lyubov , Berezina Daria , Kulakova Tatiana
Published: July 2024

See the retraction notice BIO Web of Conferences 116, 00001 (2024), https://doi.org/10.1051/bioconf/202411600001
RETRACTED: The impact of quarantine pests on forest health in Krasnoyarsk krai
Authors: Popova Valentina , Fedonova Polina , Sultson Svetlana , Kulakova Nadezhda , Mikhailov Pavel , Khizhniak Natalia
Published: July 2024

See the retraction notice BIO Web of Conferences 116, 00001 (2024), https://doi.org/10.1051/bioconf/202411600001
RETRACTED: Formation of competitiveness of agricultural enterprises of the Kyrgyz Republic
Authors: Parpieva Nurzhamal , Matikeeva Nazgul , Sulaimanova Ainura , Belek uulu Esenbek , Oganova Gulnara
Published: July 2024

See the retraction notice BIO Web of Conferences 116, 00001 (2024), https://doi.org/10.1051/bioconf/202411600001
RETRACTED: Financial mechanism of state support for agricultural cooperatives in the Republic of Tatarstan
Authors: Guz Natalya , Dubrova Marina
Published: July 2024

See the retraction notice BIO Web of Conferences 116, 00001 (2024), https://doi.org/10.1051/bioconf/202411600001
RETRACTED: Features of emotional intelligence of gifted high school students with different educational profiles
Authors: Belousova Alla , Syurtukova Maria , Drozdova Irina , Churyukin Grigorii
Published: July 2024

See the retraction notice BIO Web of Conferences 116, 00001 (2024), https://doi.org/10.1051/bioconf/202411600001
RETRACTED: Immersive technologies as a tool for increasing sustainability and environmental friendliness of tourism activities
Authors: Podolskaya Tatiana , Kalenova Saulesh , Vasyuta Eugenia , Bryukhanova Natalia , Ushakov Denis
Published: July 2024

See the retraction notice BIO Web of Conferences 116, 00001 (2024), https://doi.org/10.1051/bioconf/202411600001
RETRACTED: Socio-economic effectiveness of children with autism spectrum disorders rehabilitation
Authors: Oshkordina Alla , Goncharova Nadezhda , Borzunov Igor , Khaitova Alexandrina
Published: July 2024

See the retraction notice BIO Web of Conferences 116, 00001 (2024), https://doi.org/10.1051/bioconf/202411600001
Comparative Study of the Rosin-Rammler and Gates-Gaudin-Schuhmann Particle Size Distribution Models for Microwave-Assisted Crushing Analysis
Authors: Rasyid Muhammad A. , Aslam Azlan , Rafiei Arash , Sasmito Agus P. , Hassani Ferri
Published: July 2024

Microwaves selectively heat dielectric minerals within the ore particles during a relatively brief exposure period, inducing thermal stresses that generate cracks, thereby diminishing the structural integrity of the ore particles. The immediate effect of employing this technique is an alteration in the particle size distribution (PSD) of the comminution product. In this research, two types of diamond-bearing kimberlite ore underwent microwave irradiation before the crushing process. The microwave experimentation was carried out utilizing a multi-variable power system with a maximum capacity of 15 kW, within a single-mode cavity structure. The exposure time was adjustable to vary the input microwave energy, which ranged from 6 kJ to 270 kJ. Three distinct narrow feed size classes were examined: -31.5 +16 mm, -16 +6.7 mm, and -31.5 +6.7 mm. Each sample weighed five hundred grams. Both the microwave-treated samples and the untreated samples (as-received) were subjected to crushing using a single-roll crusher. The PSD of the crushed product was determined through a standard sieving test and subsequently analyzed using empirical PSD models. These models are advantageous for enhancing the accuracy of PSD analysis by linearizing datasets that often exhibit skewness towards the distribution's tail end. Two widely recognized empirical PSD models, the Rosin-Rammler (RR) and Gates-Gaudin-Schuhmann (GGS) models, were employed to assess how microwave pre-treatment influences the PSD of the crushed product. Various comparative parameters derived from these models, such as the P50, distribution uniformity (DP), and critical fine sizes, were evaluated for both untreated crushed samples and the samples treated with microwaves. The findings indicated that crushed products treated with microwaves generally displayed improved alignment with both PSD models in comparison to the untreated samples. Notably, the GGS model exhibited marginally higher overall r-squared values compared to the RR model. Moreover, the microwave-treated samples showcased a slightly coarser and more uniform PSD when contrasted with the untreated counterparts. Among the various microwave energy inputs tested, the lowest input at the highest power level yielded the most substantial increments in P50 and DP. Simultaneously, it led to the most significant reduction in fractions corresponding to critical fine sizes.
Extraction of Lithium from Spent Lithium-ion Batteries (LIBs) using Cation Exchange Resin
Authors: Farooq Hammad , Buzaljko Lejla , Bandyopadhyay Sulalit
Published: July 2024

Considering the lithium (Li) supply crisis and the regulations around recycling, sustainable extraction of Li from spent lithium-ion batteries (LiBs) is critical. Recently, recovery of Li from spent LiBs by water leaching has been investigated, and a high leaching selectivity towards Li is reported by fine-tuning the pH among other factors leading to the introduction of Na+ ions, which complicates selective Li recovery. Further, the low Li concentration makes the downstream precipitation challenging without an intermediate energy-intensive evaporative step. Herein, we employ Amberlite-H+, a commercially available cation exchange resin to investigate its suitability in the extraction of Li from water leachates of black mass. The water leachate containing 135 mg/L Li was prepared at optimized conditions of 25 °C, S/L (black mass/water) of 20 g/L, and a pH of 10. The extraction of Li from this water leachate by Amberlite-H+ was studied to optimize the reaction time, and various S/L ratios of Amberlite-H+ to leachate were investigated. The kinetic experiments showed that the extraction of Li from the water leachate reaches equilibrium before 30 minutes. The effect of S/L ratios was investigated at the optimized reaction time and the results showed that at S/L (g/L) of 20, 40, and 60, the uptake capacity of Li (mgLi+/gresin) is 5.34, 3.06, and 2.15, respectively. The Li-loaded resins were washed with 100 mL of 1 M HCl to desorb Li, achieving 97 – 99 % desorption yield.
Sol-gel synthesis of zirconia-based nanoparticles from the side product of tin mining
Authors: Kristiani Anis , Wiyono  , Prasetiyo Arif , Petrus Himawan Tri Bayu Murti , Jenie Siti Nurul Aisyiyah , Dwiatmoko Adid Adep , Hidayati Luthfiana Nurul , Aulia Fauzan , Sudiyarmanto  , Dahnum Deliana
Published: July 2024

Indonesia has been one of the world’s primary source of tin since the early of 19th century. Bangka island has the largest tin abundant with a side product is zircon sand (ZrSiO4). The existence of zircon (ZrSiO4) is mostly associated with some of the valuable oxide compounds (VOC) and rare earth oxides (REO). The zirconia powders were synthesized from the zircon sand of PT. Timah Tbk by caustic fusion method followed by sol-gel method. The raw material zircon sand and as-synthesized zirconia were characterized through x-ray fluorescence (XRF), x-ray diffraction (XRD), surface area analysis and porositymeter, thermogravimetric and differential scanning calorimetry analysis (TG-DSC), fourier transform infra-red (FTIR) and scanning electron microscopy (SEM) techniques. The results show that zircon sand from PT Timah Tbk contains some of VOCs, such as ZrSiO4, ZrO2, HfO2, SiO2, Al2O3, TiO2, Fe2O3 and some REOs, such as La2O3, Y2O3, Nb2O5. The fusion temperatures varied from 600 to 800 °C which resulted in an increase of the purity of ZrO2 to 76% based on the XRF analysis. The surface area analysis and porositymeter results showed the significant change in specific surface area, pore size and pore volume of as-synthesized zirconia. The specific surface area increased dramatically from 0.28 m2/g to 173.97, 125.18, and 102.14 m2/g, at fusion temperatures of 600, 700, and 800 °C, respectively. The average particle size of as-synthesized zirconia showed the significant change from 21.31μm to 34.48 nm. The results of this work open new opportunities for the development of zirconia-based nanoparticles from the side product of tin mining.
Microstructure Changes and Mechanical Properties of Stainless Steel Thin Metal Foils After Tensile Testing
Authors: Aziz Abdul , Alhamidi A. Ali
Published: July 2024

The mechanical properties and changes of microstructure of Austenitic Stainless Steel (ASS) 316L thin metal foils (TMF) were studied through uniaxial tensile tests and SEM-EBSD investigations. The differences in the uniaxial tensile test were observed in SUS 316L with varying grain size (Gs) such as 1.5 um; 3.0 um, and 9.0 um. No. martensitic phase transformation (MPT) occurred in SUS 316 TMF fine grains and coarse grains as indicated in SEM-EBSD results. The microstructure changes were indicated by the change of grain misorientation (GMO) in both SUS 316 TMF fine grains and coarse grains. Furthermore, variations in microstructure were observed in TMF with different Gs.
Investigating the role of geo-fluvial parameters on model river banks: A flume study
Authors: Khatun Supia , Jamal Mohsin , Adil Md Raghib
Published: July 2024

This experimental investigation aimed to analyze the failure profile of a model river bank composed of sand and silty clay. A model river bank with a length of 446 cm, a depth of 32 cm, and a slope of 1V:1.5H was prepared in a flume that was 550 cm long, 150 cm wide, and 60cm deep. Froude-number-based reduced-scale distorted river modeling was considered in this study. For modeling different parameters of flume, the linear scale 1:250 and depth scale 1:20 have been taken. The study was divided into two distinct series: Series-A and Series-B, each designed to explore specific soil types and moisture content variations. In Series-A, physical model tests were conducted using cohesionless soil (sand) with an initial moisture content set at 6% and 13%. Conversely, Series-B involved model banks constructed with silty clay soil, with initial moisture contents of 10% and 15%. Both series utilized a consistent model bank slope of 1V:1.5H. The drawdown conditions, set at 50% and 80% of the model riverbank’s height, were integral to the experiments in both Series-A and Series-B. The impact of moisture content, drawdown, and bank material was observed in the failure of the model bank.
Scientometric analysis of scientific production for Masonry structures with Geopolymer mortar and Textile reinforcement
Authors: Sai Krishna A. , Rajesh Kumar K.
Published: July 2024

A detailed Scientometric analysis was done on masonry structures with Geopolymer mortar and textile reinforcement. The main aim was to evaluate past research, identify common themes, detect trends, and find areas needing further study. Scopus database and Bibliometrix were used for data collection and statistical analysis. Results indicated a steady rise in publications from 2010 to 2023, with an annual growth rate of 11.91% and an average citation per document of 27.38, showing research impact. The study provides insights into the field, emphasizing emerging trends and potential research directions, with a focus on geopolymer mortar and textile reinforcement in advancing masonry structures. China contributed significantly to the research, underscoring global importance. Analysis of the journal “Composites Part B: Engineering Source” revealed key bibliometric indicators like an h-index of 54, a g-index of 92, and an m-index of 3.85, demonstrating scholarly influence. With 8938 citations from 116 articles, this journal is vital for disseminating research on masonry structures with geopolymer mortar and textile reinforcement, also highlighting areas for future exploration like “textile fibers,” “tensile strength,” and “fibers.”
Behaviour of Cold Formed Steel Column with Complex Edge Stiffened Web Openings
Authors: Logesh A. , Nirmala R. , Priyadharshini B.
Published: July 2024

Cold-Formed Steel (CFS) sections have gained in popularity due to numerous favourable properties, and with continued research into the various restrictions of such members, their utility in the construction industry has increased dramatically. CFS sections were widely utilised in structural and non-structural applications as they offer lightweight constructions, high strength-to-weight ratios, greater stiffness due to improved sectional profiles, simplicity of installation and assembly, and so on. Optimising these CFS aspects will enable the building of structures at extremely cheap costs. Buckling occurs when the column strength exceeds the cross-section yield. Owing to CFS material characteristics, edge or double stiffeners are used as a best strategy for strengthening the CFS. The primary objective of this research is to examine the strengthening method for CFS G-section columns with edge stiffened hole sections using CATIA software. The results suggest that adding edge reinforced holes to the column enhances its rigidity. The test findings revealed that CFS channel sections with edge-stiffened web apertures had a greater compression resistance than plain channel sections. The G section column with three edge reinforced holes has a low stiffness and utilised as a support element in seismically active structures.
Non-Blind Image Deblurring via Shear Total Variation Norm
Authors: LI Weiyu , ZHANG Tao , GAO Qiuli
Published: July 2024

In this paper, we propose a novel shear gradient operator by combining the shear and gradient operators. The shear gradient operator performs well to capture diverse directional information in the image gradient domain. Based on the shear gradient operator, we extend the total variation (TV) norm to the shear total variation (STV) norm by adding two shear gradient terms. Subsequently, we introduce a shear total variation deblurring model. Experimental results are provided to validate the ability of the STV norm to capture the detailed information. Leveraging the Block Circulant with Circulant Blocks (BCCB) structure of the shear gradient matrices, the alternating direction method of multipliers (ADMM) algorithm can be used to solve the proposed model efficiently. Numerous experiments are presented to verify the performance of our algorithm for non-blind image deblurring.
Makroskopische Anatomie der Zähne und des
Zahnhalteapparats
Authors: Schumann Sven
Published: July 2024

Arbeiten zur osteopathischen Zahnmedizin konzentrieren sich meist auf Störungen
des Kiefergelenks (z. B. kraniomandibuläre Dysfunktion) und/oder der
Kaumuskulatur sowie auf Gebissfehlstellungen (Dysgnathie) mit ihren vielfältigen
Auswirkungen auf den gesamten Körper. Schwerpunkt der vorliegenden Übersicht ist
dagegen eine kurze Einführung in die Anatomie der Zähne und des
Zahnhalteapparats für Osteopathen ohne zahnmedizinische Vorbildung. Ziel ist
eine möglichst kompakte und verständliche Darstellung dieses komplexen, aber
faszinierenden Themas, das noch viel Potenzial für Grundlagenforschung und
klinische Forschung birgt.
Ophthalmic Assessment and Management in Acute Facial Palsy
Authors: Malik Mohsan , Khan Raheej Shamim , Shamil Eamon
Published: July 2024

This article aims to provide insights into emerging concepts in ophthalmic manifestations in patients with facial palsy and discusses considerations used to develop patient-specific management plans in acute management.
Training Returns Among Informal Workers: Evidence from Urban Sites in Kenya and Tanzania
Authors: Torm Nina
Published: July 2024

Training contributes to economic growth through raising productivity, enabling the use of new technologies and allowing workers to raise earnings through widening their skills base. This paper uses mixed methods to examine individual returns to off-the-job training, on-the-job training and informal training focussing on informal workers in the sectors of construction, micro-trade and transport in urban areas of Kenya and Tanzania. Based on a cross-section, the analysis shows that earnings are 21 pct. higher for workers with off-the-job training compared to being self-taught, whilst the premium for on-the-job or informal training by a family member is 16 pct. The qualitative data provide further insights into the reasons for variations in gains across the different types of training and illuminates the role of informal worker associations in facilitating training access. Formal training should be made affordable and tailored to worker needs so that it becomes a worthwhile investment for informal workers.
Multitask methods for predicting molecular properties from heterogeneous data
Authors: Fisher K. E. , Herbst M. F. , Marzouk Y. M.
Published: July 2024

Data generation remains a bottleneck in training surrogate models to predict molecular properties. We demonstrate that multitask Gaussian process regression overcomes this limitation by leveraging both expensive and cheap data sources. In particular, we consider training sets constructed from coupled-cluster (CC) and density functional theory (DFT) data. We report that multitask surrogates can predict at CC-level accuracy with a reduction in data generation cost by over an order of magnitude. Of note, our approach allows the training set to include DFT data generated by a heterogeneous mix of exchange–correlation functionals without imposing any artificial hierarchy on functional accuracy. More generally, the multitask framework can accommodate a wider range of training set structures—including the full disparity between the different levels of fidelity—than existing kernel approaches based on Δ-learning although we show that the accuracy of the two approaches can be similar. Consequently, multitask regression can be a tool for reducing data generation costs even further by opportunistically exploiting existing data sources.
Compact structures for single-beam magneto-optical trapping of ytterbium
Authors: Pick J. , Schwarz R. , Kruse J. , Lisdat C. , Klempt C.
Published: July 2024

At present, the best optical lattice clocks are based on the spectroscopy of trapped alkaline-earth-like atoms such as ytterbium and strontium. The development of mobile or even space-borne clocks necessitates concepts for the compact laser-cooling and trapping of these atoms with reduced laser requirements. Here, we present two compact and robust achromatic mirror structures for single-beam magneto-optical trapping of alkaline-earth-like atoms using two widely separated optical cooling frequencies. We have compared the trapping and cooling performance of a monolithic aluminum structure that generates a conventional trap geometry to a quasi-planar platform based on a periodic mirror structure for different isotopes of Yb. Compared to prior work with strontium in non-conventional traps, where only bosons were trapped on a narrow line transition, we demonstrate two-stage cooling and trapping of a fermionic alkaline-earth-like isotope in a single-beam quasi-planar structure.
Multi-armed bandit algorithm for sequential experiments of molecular properties with dynamic feature selection
Authors: Abedin Md. Menhazul , Tabata Koji , Matsumura Yoshihiro , Komatsuzaki Tamiki
Published: July 2024

Sequential optimization is one of the promising approaches in identifying the optimal candidate(s) (molecules, reactants, drugs, etc.) with desired properties (reaction yield, selectivity, efficacy, etc.) from a large set of potential candidates, while minimizing the number of experiments required. However, the high dimensionality of the feature space (e.g., molecular descriptors) makes it often difficult to utilize the relevant features during the process of updating the set of candidates to be examined. In this article, we developed a new sequential optimization algorithm for molecular problems based on reinforcement learning, multi-armed linear bandit framework, and online, dynamic feature selections in which relevant molecular descriptors are updated along with the experiments. We also designed a stopping condition aimed to guarantee the reliability of the chosen candidate from the dataset pool. The developed algorithm was examined by comparing with Bayesian optimization (BO), using two synthetic datasets and two real datasets in which one dataset includes hydration free energy of molecules and another one includes a free energy difference between enantiomer products in chemical reaction. We found that the dynamic feature selection in representing the desired properties along the experiments provides a better performance (e.g., time required to find the best candidate and stop the experiment) as the overall trend and that our multi-armed linear bandit approach with a dynamic feature selection scheme outperforms the standard BO with fixed feature variables. The comparison of our algorithm to BO with dynamic feature selection is also addressed.
Direct numerical simulation of transition under free-stream turbulence and the influence of large integral length scales
Authors: Đurović Kristina , Hanifi Ardeshir , Schlatter Philipp , Sasaki Kenzo , Henningson Dan S.
Published: July 2024

Under the action of free-stream turbulence (FST), elongated streamwise streaky structures are generated inside the boundary layer, and their amplitude and wavelength are crucial for the transition onset. While turbulence intensity is strongly correlated with the transitional Reynolds number, characteristic length scales of the FST are often considered to have a slight impact on the transition location. However, a recent experiment by Fransson and Shahinfar [J. Fluid Mech. 899, A23 (2020)] shows significant effects of FST scales. They found that, for higher free-stream turbulence levels and larger integral length scales, an increase in the length scale postpones transition, contrary to established literature. Here, by performing well-resolved numerical simulations, we aim at understanding why the FST integral length scale affects the transition location differently at low- and high turbulence levels. We found that the integral length scales in Fransson and Shahinfar's experiment are so large that the introduced wide streaks have substantially lower growth in the laminar region, upstream of the transition to turbulence, than the streaks induced by smaller integral length scales. The energy in the boundary layer subsequently propagate to smaller spanwise scales as a result of the nonlinear interaction. When the energy has reached smaller spanwise scales, larger amplitude streaks results in regions where the streak growth are larger. It takes longer for the energy from wider streaks to propagate to the spanwise scales associated with the breakdown to turbulence, than for those with smaller spanwise scales. Thus, there is a faster transition for FST with lower integral length scales in this case.
Multi-site solar irradiance prediction based on hybrid spatiotemporal graph neural network
Authors: Yu Yunjun , Cheng Zejie , Xiong Biao , Li Qian
Published: July 2024

Constructing accurate spatiotemporal correlations is a challenging task in joint prediction of multiple photovoltaic sites. Some advanced algorithms for incorporating other surrounding site information have been proposed, such as graph neural network-based methods, which are usually based on static or dynamic graphs to build spatial dependencies between sites. However, the possibility of the simultaneous existence of multiple spatial dependencies is not considered. This paper establishes a spatiotemporal prediction model based on hybrid spatiotemporal graph neural network. In this model, we apply adaptive hybrid graph learning to learn composite spatial correlations among multiple sites. A temporal convolution module with multi-subsequence temporal data input is used to extract local semantic information to better predict future nonlinear temporal dependencies. A spatiotemporal adaptive fusion module is added to address the issue of integrating diverse spatiotemporal trends among multiple sites. To assess the model's predictive performance, nine solar radiation observation stations were selected in two different climatic environments. The average root mean square error (RMSE) of the constructed model was 38.51 and 49.90 W/m2, with average mean absolute error (MAE) of 14.72 and 23.06 W/m2, respectively. Single-site and multi-site prediction models were selected as baseline models. Compared with the baseline models, the RMSE and MAE reduce by 3.1%–20.8% and 8.9%–32.8%, respectively, across all sites. The proposed model demonstrates the effectiveness of improving accuracy in forecasting solar irradiance through multi-site predictions.
Study on the influence of spray characteristics and air flow direction on heat transfer of spray evaporative condenser
Authors: Hu Kaiyong , Chen Zhaoyi , Hu Yunqing , Sun Huan , Tian Shen , Ning Jinghong
Published: July 2024

Spray cooling is effectively utilized in evaporative condensers to achieve efficient heat and mass transfer transmission, while also effectively preventing performance degradation caused by packing blockage. The heat transfer efficiency is strongly affected by the relative flow direction between the spray and air flow. This work employs computational fluid dynamics to evaluate and examine the heat transfer effects of parallel and countercurrent air and spray flow in evaporative condensers. The findings indicate that increasing spray density and wall temperature enhances heat transfer efficiency. Smaller droplets with lower initial velocity exhibit superior heat transfer capabilities in parallel flow, while smaller droplets also perform well in countercurrent flow as long as the initial velocity is not too high. Additionally, a slight increase in air velocity improves heat transfer efficiency in both parallel and countercurrent flow conditions. It is important to note that the countercurrent condition has a larger heat transfer effect than the parallel flow.
Flexible low-profile shield for reducing back radiation of wrist-worn antenna
Authors: Phukan Arunav , Bhattacharyya Nidhi S.
Published: July 2024

A flexible conducting lossy shield is developed and demonstrated for a reduction in the back radiation of a linearly polarized X-band patch antenna for Wireless Body Area Network (WBAN) applications. The proposed structure comprises a flexible patch antenna backed by a laminated sheet of Expanded Graphite (EG). This flexible sheet is prepared from EG powder pressed uniformly over a thin adhesive tape. The conducting nature of EG is exploited, and the EG sheet is used as a protective shield to prevent back radiation emanating out of the WBAN antenna from propagating toward the human body. The antenna performance is tested over human wrist phantoms experimentally and through full wave simulation studies. The results indicate the marginal variation in the −10 dB impedance bandwidth with a slight increase in the gain and directivity values for a resonant frequency in the range 9.7–10.3 GHz (bending radius variation of 40, 30, and 20 mm and along two bending planes). A measured on-body gain of 6.7 dBi is exhibited by the antenna backed by the EG shield and bent over a 20 mm radius human wrist phantom with an S11 of −19 dB, a −10 dB % bandwidth of 8%, and a directivity of 9.4 dBi. All the other bending configurations exhibit values higher than these. Electric field and Specific Absorption Rate (SAR) studies reveal a reduction in wave penetration by the EG shield antenna inside the wrist phantom with a decrease in the SAR by a maximum of 5%. The measured front-to-back ratio values indicate the lowering of back radiation with a maximum average increase of 76% exhibited by an EG backed antenna. The developed EG shield has an additional advantage of being a standalone structure, which can be integrated with any wearable antenna for a possible reduction in the back radiation.
Static analysis and contact angle hysteresis study of bubbles in Chinese space station tank models under different gravity effects
Authors: Chen Zhewen , Chen Yi , Wu Di , Li Ce , Zhang Yuhao , Pang Huan , Duan Li , Wang Jia , Ye Zhijun , Zhang Pu , Hu Liang , Chen Shuyang , Kang Qi
Published: July 2024

In most space shuttle fuel tanks, a central column is used to secure the Propellant Management Devices. This study focuses on the distribution of fluids in such tanks. Microgravity experiments are conducted on the Chinese Space Station, and annular bubbles surrounding the central column have been observed for the first time. An in-depth study is carried out on the distribution and profile of these bubbles using perturbation methods and the Young–Laplace equation. Theoretical values for the gas–liquid interface morphology of annular bubbles under different gravity levels are obtained and compared with numerical simulation results, showing substantial agreement. The phenomenon of contact angle hysteresis of bubbles under gravity conditions was studied through simulation and theoretical analysis. Detailed analysis of the characteristics of contact angle hysteresis and corresponding drag resistance using the Wenzel model was carried out. Based on this, a numerical calculation program based on the shooting method was developed to obtain the morphology of the same bubble under different gravities. Furthermore, it was found that the theoretical maximum Bond number for circular bubbles suspended on the central column is 2, and it was observed that bubbles with equilibrium contact angles closer to 90° exhibit greater upward displacement of their centroids under varying gravity, providing theoretical support for bubble management in aerospace engineering.
Weighted compact nonlinear scheme based on smooth scale separation for self-adaptive turbulence eddy simulations
Authors: Wu Wenchang , Han Xingsi , Min Yaobing , Ma Yankai , Yan Zhen-Guo
Published: July 2024

Multiscale compressible turbulent flow is widely present in the aerospace field, and the co-existence of shock wave discontinuities and multi-scale turbulence in the flow field poses significant challenges for high-fidelity numerical simulation. To design high-order nonlinear scheme to improve the accuracy of complex turbulence simulation with stable shock wave capture, a weighted compact nonlinear scheme – targeted essentially non-oscillatory (WCNS-T) scheme is developed based on targeted essentially non-oscillatory scheme within the WCNS framework. Also, an improved variant of WCNS-T with smooth scale separation (denoted as WCNS-ST) is proposed from the perspective of both numerical convergence and accuracy. The numerical properties of different nonlinear weights are discussed in classical numerical problems, including spectral properties analysis, and two-dimensional Riemann problem. Then, the newly developed WCNS-ST scheme based on smooth scale separation was used to combine a unified turbulence model called Self-Adaptive Turbulence Eddy Simulation (SATES), which is applied to simulate subsonic flow past a 30P30N airfoil and supersonic base flow. The good convergence and numerical results are obtained using the newly developed WCNS-ST scheme, whereas WCNS-T shows worse convergence. In addition, adaptive dissipation control is further introduced for the WCNS-ST scheme, and the new variant (denoted as WCNS-STA) still shows good residual convergence and predicts more accurate results due to low numerical dissipation. The above results indicate that the proposed smooth scale separation and its WCNS-STA scheme have a good performance in SATES simulations of multiscale flow problems, making it more potential for complex engineering applications.
Coverage-dependent activation of CO over Ni/Cu(100) single atom alloys (SAAs)
Authors: Meng Weiwen , Li Ling , Zhao Rui , Liu Yu , Wang Xuan , Qiu Hengshan
Published: July 2024

Single atom alloys (SAAs) often bring new chemistry in heterogeneous catalysis and well-defined structure for the study of structure–activity relationship (SAR). However, the existing pressure gap causes the reported SARs quite divergent. Herein, we have studied CO activation over Ni/Cu(100) SAAs in ultrahigh vacuum (UHV) and millibar range. While the Ni SAAs formed on Cu(100) significantly enhance the CO adsorption strength under UHV conditions, the CO treatment at elevated pressure leads to notable surface carbon and oxygen deposition through surface reaction. Density functional theory calculations revealed that either dissociation or disproportionation is thermodynamically forbidden for the coverage of CO less than 5/16 ML. However, these two reaction pathways can be opened at higher CO coverages due to the elevated energy state involving repulsion between adsorbed CO. This work uncovers the initial activation process of CO and demonstrates one typical cause for the pressure gap in surface science study as well.
High resolution far-infrared synchrotron spectroscopy of 2-furfural conformers: Fundamental and hot bands
Authors: Chawananon Sathapana , Goubet Manuel , Pirali Olivier , Georges Robert , Roucou Anthony , Hadj Said Ikram , Senent María Luisa , Cuisset Arnaud , Asselin Pierre
Published: July 2024

In the continuity of a previous jet-cooled rovibrational study of trans and cis conformers of 2-furfural in the mid-infrared region (700–1750 cm−1) [Chawananon et al., Molecules 28 (10), 4165 (2023)], the present work investigates the far-infrared spectroscopy of 2-furfural using a long path absorption cell coupled to a high-resolution Fourier transform spectrometer and synchrotron radiation at the AILES beamline of the SOLEIL synchrotron. Guided by anharmonic calculations, vibrational energy levels and excited-state rotational constants are sufficiently predictive for a complete assignment of all fundamental and combination bands up to 700 cm−1, as well as the rovibrational analysis of 4 (1) low-frequency modes of trans-(cis-)2-furfural. A global rovibrational simulation, including far-infrared rovibrational lines and microwave and millimeter-wave rotational lines assigned in a previous study [Motiyenko et al., J. Mol. Spectrosc., 244, 9 (2007)] provides a reliable set of ground- and excited-state rotational parameters involving ring torsion, bending, and ring puckering modes of 2-furfural. In a second step, a rovibrational analysis of several hot band sequences, mainly involving the lowest frequency ring CHO torsion mode, is carried out. Reliable values of some anharmonic coefficients are obtained experimentally and could serve as a benchmark for validating advanced anharmonic calculations related to these large amplitude motions of flexible molecules.
A cold-electrode metal–oxide resistive random access memory
Authors: Cao Jifang , Chen Bing , Wang Zhijiang , Qu Junru , Zhao Jiayi , Shen Rongzong , Yu Xiao , Yu Zhiping , Liu Fei
Published: July 2024

To reduce the leakage and power consumption of metal–oxide resistive random access memory (RRAM), we propose and fabricate a cold-electrode (CE) RRAM (CE-RRAM) by extending the mechanism of cold-source FETs. First-principles calculations show that the n-Si/TiN composite CE can filter electrons with energy within the Si bandgap, which contribute to leakage current. A n-Si/TiN/HfOx/Pt CE-RRAM with low leakage current and large on/off current ratio was designed and fabricated. Comparative analysis with conventional RRAM demonstrates over a 100-fold reduction in leakage current in a high resistance state and a tenfold improvement in the Ion/Ioff ratio. Additionally, the CE-RRAM effectively suppresses the overshoot effect in terminal I–V characteristics and exhibits good endurance, maintaining a 100 Ion/Ioff ratio after 104 cycles. Furthermore, even after 104 s at 100 °C, the state remains unchanged. Moreover, the CE-RRAM demonstrates its multi-level storage capability.
Force Field X: A computational microscope to study genetic variation and organic crystals using theory and experiment
Authors: Gogal Rose A. , Nessler Aaron J. , Thiel Andrew C. , Bernabe Hernan V. , Corrigan Grove Rae A. , Cousineau Leah M. , Litman Jacob M. , Miller Jacob M. , Qi Guowei , Speranza Matthew J. , Tollefson Mallory R. , Fenn Timothy D. , Michaelson Jacob J. , Okada Okimasa , Piquemal Jean-Philip , Ponder Jay W. , Shen Jana , Smith Richard J. H. , Yang Wei , Ren Pengyu , Schnieders Michael J.
Published: July 2024

Force Field X (FFX) is an open-source software package for atomic resolution modeling of genetic variants and organic crystals that leverages advanced potential energy functions and experimental data. FFX currently consists of nine modular packages with novel algorithms that include global optimization via a many-body expansion, acid–base chemistry using polarizable constant-pH molecular dynamics, estimation of free energy differences, generalized Kirkwood implicit solvent models, and many more. Applications of FFX focus on the use and development of a crystal structure prediction pipeline, biomolecular structure refinement against experimental datasets, and estimation of the thermodynamic effects of genetic variants on both proteins and nucleic acids. The use of Parallel Java and OpenMM combines to offer shared memory, message passing, and graphics processing unit parallelization for high performance simulations. Overall, the FFX platform serves as a computational microscope to study systems ranging from organic crystals to solvated biomolecular systems.
Discrete trapping levels of localized states in amorphous silicon nitride
Authors: Novikov Yu. N. , Gritsenko V. A.
Published: July 2024

The spectrum of localized hole states (traps) in amorphous silicon nitride, a-Si3N4, is experimentally studied using the method of thermally stimulated depolarization. The experiment is compared with theoretical calculations using three models of the energy spectrum of traps: discrete spectrum (monoenergetic trap), continuous spectrum, and Gaussian trap distribution. The experiment is quantitatively described by a model of a discrete spectrum of traps with an energy of 1.15 eV and a width of no more than 0.01 eV. In the case of a continuous and Gaussian spectrum of traps, the contribution to depolarization is made by the deepest traps. The blurring of the trap energy level in a-Si3N4 due to the absence of long-range order (fluctuations in the Si–N bond length and fluctuations in the N–Si–N and Si–N–Si angles) does not exceed 0.01 eV.
Energy loss evaluation of a radial inflow turbine for organic Rankine cycle application using hierarchical entropy production method
Authors: Wang Zhiqi , Yang Huya , Li Xin , Xia Xiaoxia , Xie Baoqi , Zhang Xiaoyue
Published: July 2024

To evaluate the location and main sources of energy loss in radial inflow turbines for organic Rankine cycle application, this study proposed a hierarchical entropy production method, which is superior to the traditional pressure drop method. The method includes three levels: local entropy production, split of turbine total entropy production, and split of component entropy production. The energy loss of the radial inflow turbine under design condition and different pressure ratios is presented. The results indicate that the high-entropy production zone is primarily located at the stator trailing edge and the rotor tip clearance. The proportion of turbulent entropy production and wall entropy production in the total energy loss of the turbine is about 77% and 20%, respectively. Among the components of the radial inflow turbine, the energy loss of the rotor and diffuser is the highest, accounting for 71.9% and 13.6% of the total entropy production of the turbine, respectively. However, the stator and rotor have higher volume average entropy generation rate and area average entropy generation rate. The high-entropy production region is mainly located in the stator outlet zone and the rotor tip zone. When the pressure ratio increases from 3 to 5, the turbine efficiency decreases by 13.44%. The pressure ratio has a significant effect on the turbulent entropy production of the rotor. This method can provide insight into the energy loss characteristics of radial inflow turbines for organic Rankine cycle applications.
Compound spin Hall plasmonic lens
Authors: Li Xing , Zhang Qi , Ji Suchen , Ren Zimeng , Su Zhaoxia , Gao Zhanyi , Zhang Jing , Wang Sen
Published: July 2024

The propagation phase and the Pancharatnam–Berry phase are two primary strategies to control surface plasmon polaritons (SPPs) wave, however, hampered by the spatial conjugation and the spin conjugation, respectively. Combining these two approaches together, the conjugations are broken and a compound spin Hall plasmonic lens (SHPL) is proposed and demonstrated numerically and experimentally in the visible frequency range. The proposed strategy can be utilized to realize both transversal and longitudinal deviations of SPP focus. The positions of the SPP focus can be dynamically modulated by switching the spin states of excitation light and adjusting the phase gradient encoded onto the lens. Promising applications of the proposed SHPL include on-chip communication and polarization detection.