bluuebunny/crossref_metadata_2025 huggingface dataset:
Mathematical model analysis of effective intervention strategies on transmission dynamics of hepatitis B virus
Authors: Wodajo Firaol Asfaw , Gebru Dawit Melesse , Alemneh Haileyesus Tessema
Published: May 2023

Hepatitis B is one of the world’s most common and severe infectious diseases. Worldwide, over 350 million people are currently estimated to be persistent carriers of the hepatitis B virus (HBV), with the death of 1 million people from the chronic stage of HBV infection. In this work, developed a nonlinear mathematical model for the transmission dynamics of HBV. We constructed the mathematical model by considering vaccination, treatment, migration, and screening effects. We calculated both disease-free and endemic equilibrium points for our model. Using the next-generation matrix, an effective reproduction number for the model is calculated. We also proved the asymptotic stability of both local and global asymptotically stability of disease-free and endemic equilibrium points. By calculating the sensitivity indices, the most sensitive parameters that are most likely to affect the disease’s endemicity are identified. From the findings of this work, we recommend vaccination of the entire population and screening all the exposed and migrants. Additionally, early treatment of both the exposed class after screening and the chronically infected class is vital to decreasing the transmission of HBV in the community.
B cell-specific knockout of AID protects against atherosclerosis
Authors: Ebrahimian Talin , Dierick France , Ta Vincent , Kotsiopriftis Maria , O’Connor Miranda Jonathan , Mann Koren K. , Orthwein Alexandre , Lehoux Stephanie
Published: May 2023

Antigen-naive IgM-producing B cells are atheroprotective, whereas mature B cells producing class-switched antibodies promote atherosclerosis. Activation-induced cytidine deaminase (AID), which mediates class switch recombination (CSR), would thus be expected to foster atherosclerosis. Yet, AID also plays a major role in the establishment of B cell tolerance. We sought to define whether AID affects atherosclerotic plaque formation. We generated Ldlr-/- chimeras transplanted with bone marrow from Aicda-/- or wild-type (WT) mice, fed a HFD for 14 weeks. Decreased B cell maturation in Ldlr-/-Aicda-/- mice was demonstrated by 50% reduction in splenic and aortic BAFFR expression, a key signaling component of B2 cell maturation. This was associated with increased plasma IgM in Ldlr–/-Aicda-/- compared with Ldlr-/-WT animals. Importantly, Ldlr-/-Aicda-/- mice had reduced atherosclerotic lesion area (0.20 ± 0.03mm2) compared with Ldlr-/-WT (0.30 ± 0.04mm2, P < 0.05), although no differences in plaque composition were noted between groups. In addition, immunofluorescence analysis revealed increased splenic B and T cell areas independent of cell number. AID depletion directly inhibits atherosclerotic plaque formation.
Molecular identification of Phlebotomus kandelakii apyrase and assessment of the immunogenicity of its recombinant protein in BALB/c mice
Authors: Fayaz Shima , Raz Abbasali , Bahrami Fariborz , Fard-Esfahani Pezhman , Parvizi Parviz , Ajdary Soheila
Published: May 2023

Sand fly salivary proteins have immunomodulatory and anti-inflammatory features; hence, they are proven to perform important roles in the early establishment of Leishmania parasite in the vertebrate host. Among them, salivary apyrase with anti-hemostatic properties has a crucial role during the blood meal process. In the present study, a Genome-Walking method was used to characterize a full-length nucleotide sequence of Phlebotomus (P.) kandelakii apyrase (Pkapy). Bioinformatics analyses revealed that Pkapy is a ~ 36 kDa stable and hydrophilic protein that belongs to the Cimex family of apyrases. Moreover, recombinant proteins of Pkapy and P. papatasi apyrase (Ppapy) were over-expressed in Escherichia coli BL2 (DE3) and their antigenicity in BALB/c mice was evaluated. Dot-blot and ELISA results indicated that both recombinant apyrases could induce antibodies in BALB/c. Moreover, a partial cross-reactivity between Pkapy and Ppapy was found. In vitro stimulation of splenocytes from immunized mice with the recombinant proteins indicated cross-reactive T cell proliferative responses. Cytokine analysis revealed significant production of IFN-γ (p < 0.001) and IL-10 (p < 0.01) in response to Pkapy. In conclusion, the full-length nucleotide sequence and molecular characteristics of Pkapy were identified for the first time. Immunologic analyses indicated that Pkapy and Ppapy are immunogenic in BALB/c mice and show partial cross-reactive responses. The immunity to Pkapy was found to be a Th1-dominant response that highlights its potential as a component for an anti-Leishmania vaccine.
Fungal β-glucan-facilitated cross-feeding activities between Bacteroides and Bifidobacterium species
Authors: Fernandez-Julia Pedro , Black Gary W. , Cheung William , Van Sinderen Douwe , Munoz-Munoz Jose
Published: May 2023

The human gut microbiota (HGM) is comprised of a very complex network of microorganisms, which interact with the host thereby impacting on host health and well-being. β-glucan has been established as a dietary polysaccharide supporting growth of particular gut-associated bacteria, including members of the genera Bacteroides and Bifidobacterium, the latter considered to represent beneficial or probiotic bacteria. However, the exact mechanism underpinning β-glucan metabolism by gut commensals is not fully understood. We show that mycoprotein represents an excellent source for β-glucan, which is consumed by certain Bacteroides species as primary degraders, such as Bacteroides cellulosilyticus WH2. The latter bacterium employs two extracellular, endo-acting enzymes, belonging to glycoside hydrolase families 30 and 157, to degrade mycoprotein-derived β-glucan, thereby releasing oligosaccharides into the growth medium. These released oligosaccharides can in turn be utilized by other gut microbes, such as Bifidobacterium and Lactiplantibacillus, which thus act as secondary degraders. We used a cross-feeding approach to track how both species are able to grow in co-culture.
Probing electron localization during molecular dissociation by femtosecond strong-field ion momentum spectroscopy
Authors: Zhao Xinning , Xu Ting , Yu Xitao , Ren Dianxiang , Li Mingxuan , Zhang Xinyu , Li Xiaokai , Ma Pan , Zhang Dongdong , Wang Chuncheng , Wang Qinxin , Hu Xiaoqing , Luo Sizuo , Wu Yong , Wang Jianguo , Ding Dajun
Published: May 2023

The study of molecular valence electron dynamics and their coupling with nuclear motion is one of the frontiers of ultrafast physics and ultrafast chemistry. With time-resolved strong-field ion momentum spectroscopy, we study electron valence and nucleus wavepacket evolution on a femtosecond timescale. Two orientation-dependent bond-breaks of N2O molecules from the same electronic state are studied, and the influence of orbital hybridization and polarization effect during molecular breaking is analyzed based on the measured time-resolved asymmetric Pzsum distributions, allowing a visual representation of electron localization during the dissociation of molecules into ions and atoms. Comparison of experimental and theoretical results on orientation-dependent dissociation dynamics allows us to understand how nuclear motions evolve during fragmentation and to control ultrafast molecular reactions.
One-step synthesis of MoS2/NiS heterostructures with a stable 1T phase for an efficient hydrogen evolution reaction
Authors: Liu Yanan , Li Qiang , Zhu Yue , Chen Xiaoyu , Xue Fan , Lyu Mingxin , Li Qiheng , Chen Xin , Deng Jinxia , Miao Jun , Cao Yili , Lin Kun , Xing Xianran
Published: May 2023

Based on the good conductivity of 1T-phase MoS2 and the interfacial interaction between NiS and MoS2, the 1T-MoS2/NiS/CC catalyst has good HER performance in the alkaline system.
Homogeneous versus MOF-supported catalysis: a direct comparison of catalytic hydroboration with Ni tripodal P3E (E = Si, Ge) complexes
Authors: Barrios-Vargas Luz J. , Abeynayake Niroshani S. , Secrist Carlee , Le Nghia , Webster Charles Edwin , Donnadieu Bruno , Kaphan David M. , Roy Amitava D. , Ibarra Ilich A. , Montiel-Palma Virginia
Published: May 2023

Enhanced catalytic activity and robustness were achieved by grafting organometallic complexes onto a MOF.
Chemical species of cesium and iodine in condensed vaporized microparticles formed by melting nuclear fuel components with concrete materials
Authors: Ohnuki Toshihiko , Ye Jian , Kato Tomoaki , Liu Jiang , Takano Masahide , Kozai Naofumi , Utsunomiya Satoshi
Published: May 2023

The condensed vaporized microparticles (CVMPs) were formed by melting CsI with concrete. After the water treatment of CVMPs, some portions of Cs remained with Si in the CVMPs, even though most of the Cs and I were dissolved.
Metabolomics-based analysis in Daphnia magna after exposure to low environmental concentrations of polystyrene nanoparticles
Authors: Kelpsiene Egle , Cedervall Tommy , Malmendal Anders
Published: May 2023

Particles used in the study: 53 nm PS-NH2 and 62 nm PS-COOH. Significant metabolic responses at: 3.2 μg L−1 PS NPs.
Batch mode and continuous flow adsorption of hydrocarbon pollutants from refinery wastewater using graphene oxide derived from fish scales
Authors: Ahmad Waqas , Ullah Sajid , Ahmad Imtiaz , Muhammad Taj , Ren Yu Shuang , Ilyas Muhammad
Published: May 2023

The synthesis of graphene oxide (GO) from fish scales and its application for the adsorptive removal of organic contaminants from refinery wastewater is described in this article.
The combined effect of commercial tilapia collagen peptides and antioxidants against UV-induced skin photoaging in mice
Authors: Song Bo , Liu Dasong , Liu Tristan C. , Li Kexin , Wang Sai , Liu Jianguo , Regenstein Joe M. , Wu Yuxuan , Zhou Peng
Published: May 2023

A proposed mechanism for a mixture of collagen peptides (CP) and natural antioxidants against UV-induced photoaging.
Competitive proton-trapping strategy enhanced anti-freezing organohydrogel fibers for high-strain-sensitivity wearable sensors
Authors: Chen Zhujun , Liu He , Lin Xinyiming , Mei Xianming , Lyu Wei , Liao Yaozu
Published: May 2023

A competitive proton-trapping strategy is proposed to endow anti-freezing organohydrogel fibers with unevenly distributed ion carriers and breakable proton-migration pathways for high-strain-sensitivity wearable sensors.
Exploring the intra-4f and the bright white light upconversion emissions of Gd2O3:Yb3+,Er3+-based materials for thermometry
Authors: Ramos Talita J. S. , Longo Ricardo L. , Brites Carlos D. S. , Ferreira Rute A. S. , Malta Oscar L. , Carlos Luís D.
Published: May 2023

Upconversion broadband white light emission driven by low-power near-infrared lasers has been reported for many materials, but the mechanisms and effects related to this phenomenon remain unclear.
Direct benzylic polychlorination of (poly)azines with N-chlorosuccinimide
Authors: Liu Xueting , Wang Yaoqiang , Chen Shengda , Jia Qingqing , Wang Guoqiang , Li Shuhua
Published: May 2023

Direct benzylic polychlorination of azines was realized with NCS as the chlorine source in the absence of a catalyst or an additive.
3D printing of PLA:CaP:GO scaffolds for bone tissue applications
Authors: González-Rodríguez L. , Pérez-Davila S. , Lama R. , López-Álvarez M. , Serra J. , Novoa B. , Figueras A. , González P.
Published: May 2023

PLA:CaP:GO scaffolds were fabricated with a previously optimised biocompatible dose of GO and then characterised physicochemically and in a zebrafish model.
Microporous poly(triaminoguanidinium-amide) nanofilms with sub-nm precision for ultra-low molecular weight cut-off in nanofiltration
Authors: Sarkar Pulak , Sarkar Tapashi , Singh Harwinder , Sutariya Bhaumik , Ray Santanu , Das Amitava , Pramanik Sumit Kumar , Karan Santanu
Published: May 2023

Poly(triaminoguanidinium-amide) membranes show a high water permeance (19 L m−2 h−1 bar−1) with an ultra-low molecular weight cut-off of 163–200 g mol−1, a high rejection of Na2SO4 (≃99.7%), and a high selectivity between NaCl and Na2SO4 (≃140).
Electrocatalytic urea oxidation: advances in mechanistic insights, nanocatalyst design, and applications
Authors: Ge Weiyi , Lin Liping , Wang Shu-Qi , Wang Yechen , Ma Xiaowei , An Qi , Zhao Lu
Published: May 2023

The advancement of UOR is hindered by sluggish kinetics. Hence, we overview UOR mechanisms, nanocatalyst design strategies, and applications in energy conversion to reduce energy consumption and broaden the research fields of electrocatalysis.
Rhodamine B as an efficient multifunctional passivator for the improvement of perovskite solar cell performance
Authors: Jin Lei , Li Yi-Lin , Zhou Jian , Huang Chun-Mei , Liu Xing
Published: May 2023

Multifunctional RhB is applied for the passivation of defects in perovskite films, decreasing defect density, suppressing ionic migration and forming extra interface electric field. The PCE of a RhB modified PSC with improved stability is increased from 18.79% to 20.70%.
Mn2+-doped organic–inorganic hybrids (C8H20N)2Zn1−xMnxBr4 as sub-micrometer green phosphors for Mini-LEDs/Micro-LEDs
Authors: Wang Sixiang , Wang Yichang , Yoon DaeHo , Li Tianrong , Wang Yuhua
Published: May 2023

Mn2+-doped organic–inorganic hybrids (C8H20N)2Zn1−xMnxBr4 as sub-micrometer green phosphors for Mini-LEDs/Micro-LEDs.
Optical markers of magnetic phase transition in CrSBr
Authors: Linhart W. M. , Rybak M. , Birowska M. , Scharoch P. , Mosina K. , Mazanek V. , Kaczorowski D. , Sofer Z. , Kudrawiec R.
Published: May 2023

Here, we investigate the role of the interlayer magnetic ordering of CrSBr in the framework of ab initio calculations and by using optical spectroscopy techniques.
Mechanochemical preparation of graphdiyne (CnH2n−2) based Ni-doped MoS2S-scheme heterojunctions within situXPS characterization for efficient hydrogen production
Authors: Liu Zhenkun , Li Youji , Jin Zhiliang
Published: May 2023

The hydrogen production activity of NMG-20 using TEOA (volume fraction is 15% and pH = 9) was 5012 μmol g−1h−1, which is 17.7, 11.2, and 3.6 times higher than those of NiS, GDY and MoS2, and 36.8% higher than that of the doped product NM-3.
Needle detection and localisation for robot‐assisted subretinal injection using deep learning
Authors: Zhou Mingchuan , Guo Xiangyu , Grimm Matthias , Lochner Elias , Jiang Zhongliang , Eslami Abouzar , Ye Juan , Navab Nassir , Knoll Alois , Nasseri Mohammad Ali
Published: May 2023

Subretinal injection is a complicated task for retinal surgeons to operate manually. In this paper we demonstrate a robust framework for needle detection and localisation in robot‐assisted subretinal injection using microscope‐integrated Optical Coherence Tomography with deep learning. Five convolutional neural networks with different architectures were evaluated. The main differences between the architectures are the amount of information they receive at the input layer. When evaluated on ex‐vivo pig eyes, the top performing network successfully detected all needles in the dataset and localised them with an Intersection over Union value of 0.55. The algorithm was evaluated by comparing the depth of the top and bottom edge of the predicted bounding box to the ground truth. This analysis showed that the top edge can be used to predict the depth of the needle with a maximum error of 8.5 μm.
A domain translation network with contrastive constraint for unpaired motion image deblurring
Authors: Zhao Bingxin , Li Weihong
Published: May 2023

Most motion deblurring methods require a large amount of paired training data, which is nearly unreachable in practice. To overcome the limitation, a domain translation network with contrastive constraint for unpaired motion image deblurring is proposed. First, a domain translation network with two streams, a sharp domain translation stream and a blurred domain translation stream, to handle unpaired sharp and blurred images from the real world is presented. Second, a contrastive constraint loss in the deep intermediate level for the two streams to promote the network to produce deblurring results close to the real sharp image is proposed. Third, distinct loss functions for the two streams to preserve the edge and texture detail of the deblurring image is designed. Extensive experiments on several benchmark datasets demonstrate that the proposed network achieves better visual performance than the current state‐of‐the‐art methods for unpaired motion image deblurring.
Metabolomics and its applications in assisted reproductive technology
Authors: Gao Jingying , Xiao Yan
Published: May 2023

Metabolomics, an emerging omics technology developed in the post‐gene age, is an important part of systems biology. It interprets the pathophysiological state of the subject by quantitatively describing the dynamic changes of metabolites through analytical methods, mainly mass spectrometry (MS) and nuclear magnetic resonance (NMR). Assisted reproductive technology (ART) is a method used to manipulate sperm, oocytes, and embryos to achieve conception. Recently, several studies have reported that metabolomics methods can be used to measure metabolites in ART samples; these metabolites can be used to evaluate the quality of gametes and embryos. This article reviews the progress of research on metabolomics and the application of this technology in the field of ART, thus providing a reference for research and development directions in the future.
Dynamic stability assessment of interconnected thermal‐SsGT‐solar photovoltaic‐EV power system with ARO optimized IDN‐FOID amalgamated controller
Authors: Saha Arindita , Babu Naladi Ram , Dash Puja , Acharya Biswaranjan , Bhaskar Mahajan Sagar , Khan Baseem
Published: May 2023

To succeed over the sudden load‐frequency variations in interlinked power systems, an equilibrium must be maintained between power generations and losses. The major problem associated to manifold interlinking arenas of power systems is load frequency control. In this paper, a multiple‐arena scheme is examined which encompasses thermal and split shaft gas turbine plants. Here, artificial rabbit optimization (ARO) is applied to procure the premium standards of the supplementary controller. The projected controller is the amalgamation of integer order integral‐derivative with filter (IDN) and fractional order integral‐derivative (FOID). So, the amalgamation is IDN‐FOID. Henceforth, the ARO augmented IDN‐FOID controller is recognized. The ARO augmented IDN‐FOID supplementary controller delivers enhanced outcomes related to additional secondary controllers like I, PI, and PIDN. Valuation articulates about the improved act of ARO over added algorithms using the IDN‐FOID controller related to converging nature, transient profile, and steady‐state assessment. Assessment is done in the presence of non‐linearities in generation rate constraints and time delay. It is also detected that scheme potent outcomes with the IDN‐FOID controller are superior when the scheme is instructed with solar photovoltaic, electric vehicles, solid oxide fuel cells, and ultra‐capacitor. The ARO optimized IDN‐FOID controller is the anticipated arrangement for the measured scheme.
Endoscopic features of low-grade dysplastic Barrett’s
Authors: He Tony , Iyer Kiran Gopinath , Lai Mark , House Eloise , Slavin John L , Holt Bronte , Tsoi Edward H , Desmond Paul , Taylor Andrew C F
Published: May 2023

Background and study aims Barrett’s esophagus (BE) with low-grade dysplasia (LGD) is considered usually endoscopically invisible and the endoscopic features are not well described. This study aimed to: 1) evaluate the frequency of visible BE-LGD; 2) compare rates of BE-LGD detection in the community versus a Barrett’s referral unit (BRU); and 3) evaluate the endoscopic features of BE-LGD.

Patients and methods This was a retrospective analysis of a prospectively observed cohort of 497 patients referred to a BRU with dysplastic BE between 2008 and 2022. BE-LGD was defined as confirmation of LGD by expert gastrointestinal pathologist(s). Endoscopy reports, images and histology reports were reviewed to evaluate the frequency of endoscopically identifiable BE-LGD and their endoscopic features.

Results A total of 135 patients (27.2%) had confirmed BE-LGD, of whom 15 (11.1%) had visible LGD identified in the community. After BRU assessment, visible LGD was detected in 68 patients (50.4%). Three phenotypes were observed: (A) Non-visible LGD; (B) Elevated (Paris 0-IIa) lesions; and (C) Flat (Paris 0-IIb) lesions with abnormal mucosal and/or vascular patterns with clear demarcation from regular flat BE. The majority (64.7%) of visible LGD was flat lesions with abnormal mucosal and vascular patterns. Endoscopic detection of BE-LGD increased over time (38.7% (2009–2012) vs. 54.3% (2018–2022)).

Conclusions In this cohort, 50.4% of true BE-LGD was endoscopically visible, with increased recognition endoscopically over time and a higher rate of visible LGD detected at a BRU when compared with the community. BRU assessment of BE-LGD remains crucial; however, improving endoscopy surveillance quality in the community is equally important.
Studying dimensions of representation: introducing the Belgian RepResent panel (2019–2021)
Authors: Michel Elie , Feitosa Fernando , Lefevere Jonas , Pilet Jean-Benoît , van Erkel Patrick , van Haute Emilie
Published: May 2023

This research note presents the RepResent Belgian Panel (RBP). The RBP is a voter panel survey consisting of four waves fielded to a sample of voters in Belgium around the May 2019 federal, regional, and European elections in Belgium. It provides unique data on about 250 variables for a quota sample of the same respondents, pre-2019 elections (N = 7351), post-2019 elections (N = 3909), one year after the elections (N = 1996), and 2 years after the elections (N = 1119). The RBP panel dataset was designed to analyse voters’ political attitudes and behaviours, notably on different dimensions of democratic representation, and with a specific focus on democratic resentment (e.g. citizens’ attitudes towards democracy such as distrust and alienation, but also behaviours such as abstention, protest, or voting for anti-establishment parties). Its longitudinal structure allows to explore the political dynamics at play in Belgium throughout the lengthy government formation process. Finally, the last two waves of the RBP were fielded during the Covid-19 pandemic, allowing to explore public opinion before and during this global crisis. The RBP should be of interest to scholars of public opinion and electoral studies.
Global biomass fires and infant mortality
Authors: Pullabhotla Hemant K. , Zahid Mustafa , Heft-Neal Sam , Rathi Vaibhav , Burke Marshall
Published: May 2023

Global outdoor biomass burning is a major contributor to air pollution, especially in low- and middle-income countries. Recent years have witnessed substantial changes in the extent of biomass burning, including large declines in Africa. However, direct evidence of the contribution of biomass burning to global health outcomes remains limited. Here, we use georeferenced data on more than 2 million births matched to satellite-derived burned area exposure to estimate the burden of biomass fires on infant mortality. We find that each additional square kilometer of burning is associated with nearly 2% higher infant mortality in nearby downwind locations. The share of infant deaths attributable to biomass fires has increased over time due to the rapid decline in other important causes of infant death. Applying our model estimates across harmonized district-level data covering 98% of global infant deaths, we find that exposure to outdoor biomass burning was associated with nearly 130,000 additional infant deaths per year globally over our 2004 to 2018 study period. Despite the observed decline in biomass burning in Africa, nearly 75% of global infant deaths due to burning still occur in Africa. While fully eliminating biomass burning is unlikely, we estimate that even achievable reductions—equivalent to the lowest observed annual burning in each location during our study period—could have avoided more than 70,000 infant deaths per year globally since 2004.
Attacks and remedies in online public opinion reversal events
Authors: Wu Yiman , Ren Wei , Zhang Yi
Published: May 2023

Collective attacks related to controversial issues are pervasive in online communication. However, public opinion
is often reversed later when earlier reports are revealed to be misinformation, which may lead to remedies offered to the victim
by netizens. We call such phenomena online public opinion reversal (POR) events, which reflect group polarization from attack to
remedy. This paper explores the pragmatic strategies that netizens employ to launch attacks and offer remedies in such events,
examining a dataset including 300 netizen-generated attacking comments and 300 remedial comments collected on Weibo. The study
identified two main categories of online attack strategies and seven types of remedial strategies. Chinese netizens prefer to
employ on-record strategies when launching attacks. When an earlier report is revealed to be fake, they employ apology as the most
frequent remedial strategy. Preferences for different attacking and remedial strategies and potential influencing factors are also
discussed.
A review of plasma-induced defects: detection, kinetics and advanced management
Authors: Nunomura Shota
Published: May 2023

Plasma-induced defects are often recognized in state-of-the-art semiconductors, high-efficiency solar cells and high-sensitivity image sensors. These defects are in the form of a dangling bond, bond deformation, or impurity/residual, which impacts on the device performance and reliability. The defects are introduced via plasma-material interactions during manufacturing processes such as deposition, etching and implantation. So, the management of defects throughout the manufacturing is important for high-performance device fabrication. In this review, we overview the generation and recovery of plasma-induced defects in order to develop the defect-managed advanced plasma processing for further improving the device performances. The defect generation and recovery are described, based on the recent results of in-situ and real-time detection of plasma-induced defects. Two examples are presented: the growth of hydrogenated amorphous silicon and the surface passivation of crystalline silicon for high-efficiency solar cell applications.
Measurement and analysis of an optimized Jiles–Atherton model considering the influence of temperature applied in magnetic shielding devices
Authors: Sun Jinji , Ren Jianyi , Zhou Weiyong
Published: May 2023

Magnetic shielding devices work at different temperatures due to the influence of gas chamber and environmental temperature in the application of ultra-highly sensitive spin exchange relaxation free (SERF) magnetometers. To accurately evaluate the residual magnetic field (MF) of a magnetic shielding device at different temperatures, it is necessary to build a magnetization model considering temperature. However, the modeling of permalloy’s magnetization properties and the measurement of residual MF in magnetic shielding devices at different temperatures have not been considered. In this paper, an optimized Jiles–Atherton (JA) model of permalloy considering temperature is constructed, in which parameters are extracted using a particle swarm optimization algorithm. To further verify the effectiveness of the model in the magnetic shielding device, it is applied to the residual MF simulation of magnetic shielding devices and verified by measurement. The optimized JA model considering temperature improves the calculation accuracy of magnetic shielding devices, which is of great significance for the application of ultra-highly sensitive SERF magnetometers.
Intelligent fault diagnosis of gear crack based on side frequency feature under different working conditions
Authors: Xiao Yuanying , Chen Longting , Chen Siyu , Hu Zehua , Tang Jinyuan
Published: May 2023

Aiming at the problem of gear crack fault diagnosis, an intelligent diagnosis method based on side frequency feature is proposed. It enhances the fault information representation ability of the extracted features and the fault identification ability of the model. Firstly, according to the side frequency distribution characteristics of gear crack fault, the side frequency energy features are quantified, and a relatively complete feature set is constructed by combining the time domain features; Secondly, an evaluation method of feature effectiveness is designed to obtain the optimal feature subset; Finally, a three-stage training network is constructed to achieve an increase in fault diagnosis rate. The test results under different working conditions show that the proposed method can more completely represent the fault information and effectively improve the fault diagnosis rate when compared with the machine learning model of a general two-layer network and feature extraction methods based on entropy features.
Bicycling geodesics are Kirchhoff rods
Authors: Bor Gil , Jackman Connor , Tabachnikov Serge
Published: May 2023

A bicycle path is a pair of trajectories in

R

n

, the ‘front’ and ‘back’ tracks, traced out by the endpoints of a moving line segment of fixed length (the ‘bicycle frame’) and tangent to the back track. Bicycle geodesics are bicycle paths whose front track’s length is critical among all bicycle paths connecting two given placements of the line segment. We write down and study the associated variational equations, showing that for

n
⩾
3

each such geodesic is contained in a 3-dimensional affine subspace and that the front tracks of these geodesics form a certain subfamily of Kirchhoff rods, a class of curves introduced in 1859 by Kirchhoff, generalizing the planar elastic curves of Bernoulli and Euler.
Automated deep learning auto-segmentation of air volumes for MRI-guided online adaptive radiation therapy of abdominal tumors
Authors: Ahunbay Ergun , Parchur Abdul K , Xu Jiaofeng , Thill Dan , Paulson Eric S , Li X Allen
Published: May 2023

Objective. In the current MR-Linac online adaptive workflow, air regions on the MR images need to be manually delineated for abdominal targets, and then overridden by air density for dose calculation. Auto-delineation of these regions is desirable for speed purposes, but poses a challenge, since unlike computed tomography, they do not occupy all dark regions on the image. The purpose of this study is to develop an automated method to segment the air regions on MRI-guided adaptive radiation therapy (MRgART) of abdominal tumors. Approach. A modified ResUNet3D deep learning (DL)-based auto air delineation model was trained using 102 patients’ MR images. The MR images were acquired by a dedicated in-house sequence named ‘Air-Scan’, which is designed to generate air regions that are especially dark and accentuated. The air volumes generated by the newly developed DL model were compared with the manual air contours using geometric similarity (Dice Similarity Coefficient (DSC)), and dosimetric equivalence using Gamma index and dose-volume parameters. Main results. The average DSC agreement between the DL generated and manual air contours is 99% ± 1%. The gamma index between the dose calculations with overriding the DL versus manual air volumes with density of 0.01 is 97% ± 2% for a local gamma calculation with a tolerance of 2% and 2 mm. The dosimetric parameters from planning target volume—PTV and organs at risk—OARs were all within 1% between when DL versus manual contours were overridden by air density. The model runs in less than five seconds on a PC with 28 Core processor and NVIDIA Quadro® P2000 GPU. Significance: a DL based automated segmentation method was developed to generate air volumes on specialized abdominal MR images and generate results that are practically equivalent to the manual contouring of air volumes.
Lattice dynamics and pressure induced metallization of solid iodanil (C6I4O2) studied using density functional theory
Authors: Mondal S , Ayadi Tarek , Lebègue Sébastien , Gupta M K , Mittal R , Vaitheeswaran G
Published: May 2023

A detailed ab initio study addressing the structural, lattice dynamics and pressure induced metallization has been carried out for solid iodanil (C6I4O2). The computed ground state structural properties reveal the crucial role of considering van der Waals correction in determining these properties. An excellent agreement can be noticed between our computed zone centered phonon frequencies and experimentally reported results. Though computed phonon dispersion confirms the dynamical stability of solid iodanil in the P2

1
/c symmetry, a softening of the transverse acoustic phonon mode can be observed with pressure along the D-B direction. At 22 GPa, i.e. across insulator-metal transition, the TA branch along D-B directions hardened, where the role of optical phonon mode (A
u
) is prominent. In addition, the elastic constants were also calculated to ascertain the mechanical stability of the solid iodanil. Moreover, the electronic band structure has been calculated using the quasiparticle G

0
W0 approximation which results in a band gap of 2.49 eV. This value is significantly larger than the value obtained by the generalized gradient approximation, thus emphasizing the importance of quasiparticle correction in solid iodanil. This study clearly shows a reduction of the band gap under pressure and hence result in a band overlap eventually driving iodanil to metallize around 22 GPa. The pressure variation of the inter- and intramolecular bond lengths as well as the charge density plots explain the significant role of the intermolecular I-I distance in understanding the metallization of solid iodanil.
Classic analogue of Autler–Townes-splitting transparency using a single magneto-optical ring resonator
Authors: Wu 吴 Liting 利婷 , Cao 曹 Wenkang 文康 , Jiang 蒋 Haolin 昊林
Published: May 2023

We show that an optical transparency can be obtained by using only one single magneto-optical ring resonator. This effect is based on the splitting of counterclockwise and clockwise modes in the ring resonator. Within a proposed resonator-waveguide configuration the superposition between the two degeneracy broken modes produces a transparency window, which can be closed, open, and modified by tuning the applied magnetic field. This phenomenon is an analogue of Autler–Townes splitting, and the magnetic field is equivalent to the strong external pump field. We provide a theoretic analysis on the induced transparency, and numerically demonstrate the effect using full-wave simulation. Feasible implication of this effect and its potential applications are also discussed.
Influence of free-stream turbulence on the boundary layer stability of a wind turbine airfoil and near wake
Authors: Fava T C L , Lobo B A , Nogueira P A S , Schaffarczyk A P , Breuer M , Henningson D S , Hanifi A
Published: May 2023

Free-stream turbulence (FST) alters the boundary layer of wind turbine blades, changing the hydrodynamic stability and near wake. Large-eddy simulations (LES) of a blade section with a laminar separation bubble for several turbulence intensities (TI) and a Reynolds number of 105 are performed. The effects of boundary-layer streaks generated by FST on Tollmien-Schlichting (TS) and Kelvin-Helmholtz (KH) instabilities are analyzed with a model based on the parabolized stability equations (PSE). Two competing effects on flow stability are identified. The spanwise-averaged mean-flow distortion stabilizes primary TS/KH modes for increasing TI. However, this contribution seems dominant only for TI ≥ 8.6%. For lower TI, the spanwise-oscillating distortion caused by streaks destabilizes the flow, and the growth rates of secondary modal instabilities increase with the streak amplitude. The destabilization occurs mainly at spanwise locations with negative streaks since the inflection point shifts away from the wall, enhancing inviscid instabilities. Inflection points in the spanwise direction formed by the streaks also contribute to the destabilization. The modal structures from PSE and LES agree. Finally, the trailing-edge near-wake coherent structures are more energetic for TI ≥ 8.6% due to the partial stabilization of modal instabilities, delaying the turbulent breakdown.
On the performance of the helix wind farm control approach in the conventionally neutral atmospheric boundary layer
Authors: Taschner E , van Vondelen AAW , Verzijlbergh R , van Wingerden JW
Published: May 2023

The performance of wind farms can substantially increase when their individual turbines deviate from their own greedy control strategy and instead also take into account downstream turbines operating in the wake. The helix approach is a recently introduced dynamic wind farm control strategy that tackles this issue by leveraging individual pitch control to accelerate wake recovery. Its effective implementation requires detailed knowledge about the scaling between control input and the resulting power gain and turbine loading across the farm. In the present work this scaling is explored by means of large-eddy simulation of a two-turbine farm in the conventionally neutral atmospheric boundary layer. A parameter sweep for the amplitude of the helix is performed showing monotonous increase of the farm’s power output with increasing pitch amplitude within the considered range of zero to six degrees. The scaling of the power gain suggests that a threshold amplitude should be exceeded for effective speed-up of the wake recovery, whereas the damage equivalent loads computed for the turbines indicate an upper limit for the amplitude despite increasing power gains.
Study on the yaw-based wake steering control considering dynamic flow characteristics for wind farm power improvement
Authors: Yu Xin , Liu Yongqian , Chen Tao , Meng Hang , Li Li
Published: May 2023

Wake steering is one of the wind farm control strategies that can effectively reduce wake losses and increase power generation. Upstream wind turbines are set with yaw misalignment angles to deflect their wake away from downstream wind turbines, which will alleviate the wake effect. Currently, the yaw misalignment angles of the wind turbines are optimized through CFD or analytical wake models with a fixed inflow wind direction. However, wind turbines operate in rapidly changing wind directions where they cannot immediately track the optimized yaw misalignment angles owing to the slow yaw mechanism as expected. Therefore, a dynamic yaw control method is proposed in this study with the aim of balancing the energy gain and the number of yaw movements. Firstly, in order to improve efficiency, the yaw misalignment set points of wind turbines are optimized with different wind conditions based on the steady wake model. Then, we illustrate the procedure for determining the yaw misalignment angles for dynamic wind conditions. Finally, the performance of the yaw controller under the measured inflow condition is analyzed for the case of two-turbine array. It was found that the optimized yaw misalignment angles based on the steady model are applied to the dynamic control under changing wind direction, where the energy gain does not reach the estimated value using the static optimized control.
A RANS-based surrogate model for simulating wind turbine interaction
Authors: Criado Risco J. , van der Laan M. P. , Pedersen M. M. , Meyer Forsting A. , Réthoré P.-E.
Published: May 2023

A new wake surrogate model based on Reynolds-averaged Navier-Stokes (RANS) single rotor simulations is presented. The model relies on a series of three-dimensional pre-calculated deficit and added turbulence intensity flow fields, stored in a look-up table (LUT) as a function of the thrust coefficient and the ambient turbulence intensity. For any combination of these parameters, the flow around a wind turbine can be predicted by linearly interpolating within the look-up table. Furthermore, the resulting three-dimensional flow fields from different turbine sources can be superposed linearly to calculate the total wind farm flow. The model is implemented in PyWake and benchmarked against other, commonly employed engineering wake models, namely the Gaussian-Bastankhah, the N. O. Jensen and the Zong models, where RANS wind farm simulations are used as reference. In both full and partial wake cases, the surrogate model achieves a higher accuracy than any other model. Besides providing an accuracy comparable to a full RANS solution, the model can compute a flow case in the order of 1 s on a single processor. The main disadvantage is that the generation of the look-up table is time consuming, computationally expensive and can be memory demanding (especially if more inputs, such as the yaw misalignment angle, stability, etc. are added). Nevertheless, generating the LUT only has to be done once per wind turbine type.
Experimental and numerical study of the wake deflections of scaled vertical axis wind turbine models
Authors: Huang Ming , Sciacchitano Andrea , Ferreira Carlos
Published: May 2023

Wake steering of vertical axis wind turbines (VAWTs) is investigated experimentally and numerically via stereoscopic particle image velocimetry and Reynolds averaged Navier-Stokes simulations. Three different blade pitch angles (-10°, 0°, 10°) of straight H-type VAWTs are adopted to deflect and deform the wake. The experimental results confirm the efficacy of blade pitching on the wake steering, and validate the simulation for both moderate and significant wake deflections. The simulation is then extended to full-scale VAWTs, exploring the wake deflection effects on the power performance of VAWT arrays. The effects of inter-turbine distances and pitching configurations are considered. With the upwind VAWT deflecting the wake, the overall power coefficient is increased by 41%.
RANS simulation of a wind turbine wake in the neutral atmospheric pressure-driven boundary layer
Authors: Baungaard M , van der Laan M P , Wallin S , Abkar M
Published: May 2023

Reynolds-averaged Navier-Stokes (RANS) simulations of a single wind turbine wake in the neutral atmospheric pressure-driven boundary layer (PDBL) are conducted and compared to RANS simulations with inflow based on the more traditional log-law. The latter is valid in the neutral atmospheric surface layer (ASL), while the PDBL is a better representation of the whole atmospheric boundary layer (ABL). It is found that the wake results of the two types of simulations become more similar for increasing ABL height to rotor diameter ratio. In fact, the ASL is shown to be a special asymptotic case of the PDBL. The RANS simulations are also compared to a large-eddy simulation (LES) PDBL case, where it is found that both the ASL and PDBL RANS simulations compare well with the reference LES data in the wake region, while the RANS PDBL compares better with the data in the upper region of the domain.
The effect of the tower’s modeling on the aero-elastic response of the NREL 5 MW wind turbine
Authors: Bernardi Claudio , Della Posta Giacomo , De Palma Pietro , Leonardi Stefano , Bernardoni Federico , Bernardini Matteo , Cherubini Stefania
Published: May 2023

In this work, we aim at evaluating the aeroelastic response of the blades of a standalone NREL 5MW wind turbine by means of a high-fidelity fluid-structure interaction solver based on large-eddy simulation, and compare the results with those of engineering-fidelity methods based on the Blade Element Momentum (BEM) theory. For the latter, we use the software OpenFAST [1], which couples an aerodynamic solver based on the BEM theory with a solver of the blades’ structural dynamics. Concerning the computational fluid dynamics (CFD) solver, the tower and nacelle are modeled by means of an immersed boundary method, whereas the aeroelastic rotor is modeled by an actuator line model coupled with a Computational Structural Dynamics (CSD) solver representing the blades as rotating cantilever beams. A comparison of the CFD-CSD results with the corresponding ones obtained by OpenFAST shows that the predicted displacements at the blade tip remarkably differ between the two approaches in correspondence of the passages of the blades in front of the tower. Indeed, the interaction between the blades and the tower introduces a significant perturbation in the local aerodynamics that leads to a drop of the displacement at the tip of the blade and of the root reaction magnitude, which appear to be not accurately described by OpenFAST.
Large-Eddy Simulations of wind turbine wakes in sheared inflows
Authors: Parinam Anand , Benard Pierre , Terzi Dominic von , Viré Axelle
Published: May 2023

Modern-day wind turbines are growing continuously in size and reach diameters of more than 200m in an effort to meet the fast growing demand for wind energy. As a consequence, the rotors are exposed to larger velocity variations in the approach flow due to the presence of shear, veer and turbulence. The shear of the ambient flow is an important effect that can impact the wake of a turbine twofold: one way is how the wake evolves in the sheared flow; the other way is by impacting the performance and loading of the turbine and, hence, the wake it produces. Both ways can affect the size, shape, spreading and recovery of the turbine wake and, consequently, impact on loads and power output of turbines located downstream. In this study, we analyzed the influence of different inflow wind shear configurations on the evolution of the wake behind the IEA 15MW reference wind turbine by means of high-resolution Large-Eddy Simulations. In order to isolate the shear effects, the mean and hub height wind speed of the inflow was kept constant by prescribing linear shear profiles without turbulence. The influence of Coriolis forces and thermal stratification are neglected. In addition, the effect of the imposed shear on the turbine’s power and thrust, and the effect of including the nacelle in the simulation, were monitored.
Towards the multi-scale Kalman filtering of dynamic wake models: observing turbulent fluctuations and wake meandering
Authors: Braunbehrens R. , Tamaro S. , Bottasso C. L.
Published: May 2023

When dynamic wake models are augmented with a Kalman filter, they can provide dynamic estimates of the turbine inflows. Such estimators –especially when implemented through readily available operational data– can support a variety of practical applications in wind farm operation and monitoring, power forecasting, and others. The present work represents a first step towards a multi-scale approach for the filtering of dynamic wake models, aimed at estimating both small-fast and large-slow scales in the flow. The small-fast scales are caused by flow turbulence, which in turn also causes wake meandering, whereas the large-slow ones represent the propagation of macroscopic changes of ambient conditions (e.g., the passing of a wind direction change front throughout a farm). It is argued that the small-fast-scale problem is more difficult to address, because of the lack of measurements between turbines, and it is therefore the focus of this paper. An ensemble Kalman filter is developed that, based exclusively on power measurements from the turbines, estimates small-fast changes in wind speed and wake position. CFD simulations are used to characterize the performance of the proposed approach. Results indicate that – notwithstanding the lack of measurements of the flow as it travels from one turbine to the other– the filter is still able to provide for reasonable estimates of the inflow at the downstream machine. Additionally, it is shown that the filter typically distinguishes between effects caused by ambient flow changes from those due to wake meandering.