bluuebunny/crossref_metadata_2025 huggingface dataset:
Histone Lysine Methyltransferases
Authors: O Donovan Daniel H. , Hsu Jessie , Liu Huayang , Read Jon A.
Published: September 2024

Following the FDA approval of Azacitidine and Vorinostat in the mid-2000s, there has been a growing interest in identifying new epigenetic drug targets. Histone methyltransferases (HMTs) have garnered significant attention due to their role in transcription, cell fate regulation and oncogenesis. Among the HMTs, lysine methyltransferases (KMTs) such as EZH2, DOT1L, and NSD2 have emerged as focal points owing to their strong genetic association with cancers. The KMT target class was shown to be readily ligandable, with two orthosteric binding sites (SAM and substrate peptide) and multiple domains associated with histone reader functions. EZH2 and DOT1L inhibitors have shown promise and rapidly progressed into clinical trials. In early 2021, the EZH2 inhibitor tazemetostat became the first KMT targeted drug to receive FDA approval, underscoring the therapeutic viability of this target class. Given the growing understanding of KMT enzyme biology and recent progress in developing chemistry to target specific sites, it seems likely that additional impactful medicines targeting this enzyme class can be expected in the future.
Directly Targeting RNA with Drug-like Small Molecules
Authors: Wu Hao , Bagal Sharan K. , Jin Meizhong
Published: September 2024

We are entering an era of innovative small molecule drug discovery by leveraging new modalities. Among them, directly targeting RNA and modulating RNA processes represents an exciting direction. Directly targeting RNA provides unique therapeutic opportunities that are not accessible for other modalities; more importantly, some of the approaches have achieved clinical success. As of now, human RNA as a drug target class has largely remained underexplored and holds significant potential. However, there are considerable challenges and risks, including target selection, mechanism of action, hit finding, validation and optimization, and translation of small molecule-RNA binding to functional phenotype, to be carefully evaluated to avoid pitfalls and increase the chances of success.
Organic photosensitized aziridination of alkenes
Authors: Wu Chunying , Zhu Yunbo
Published: September 2024

A new organic photocatalysis-mediated aziridination of alkenes has been developed. This strategy enables installation of the strained aziridines into alkenes, pharmaceutical-derived olefins and natural products.
A chromatographic relay conjugated photoredox strategy: S, Se-pharmacophore from alkenes via formal [2+2+1] heteroannulation
Authors: Hoque Injamam Ul , Debnath Saradindu , Lo Rabindranath , Maity Soumitra
Published: September 2024

A strategy involving alumina chromatography coupled with photoredox to produce 2-amino-dihydrothiophenes and their selenium analogues via a formal [2+2+1] heteroannulation between alkenes, thio(seleno)cyanate, and bromomalonates is reported.
Carbene transfer reactivity from a nickelacyclobutane
Authors: Sansores-Paredes María L. G. , Lutz Martin , Moret Marc-Etienne
Published: September 2024

A carbene-transfer reaction from an isolated nickelacyclobutane to an isocyanide to form a ketenimine is reported.
Molecular engineering and structure–property relationship based on D–A chlorophyll derivative and the application in organic solar cells
Authors: Zhang Kaiyan , Li Ting , Song Peng , Ma Fengcai , Li Yuanzuo
Published: September 2024

This work clarifies the structure–property relationship of chlorophyll derivatives and the photo-response mechanism of intermolecular charge transfer, providing a theoretical basis for developing valuable chlorophyll-based OSCs.
Dissociative ionization and post-ionization alignment of aligned O2 in an intense femtosecond laser field
Authors: Fukahori Shinichi , Kubo Ayumi , Hasegawa Hirokazu
Published: September 2024

Molecular orbitals from which electrons are emitted in many dissociative ionization pathways of O2 in an intense laser field are revealed by O+ kinetic energy distribution varied and associated with time evolution of the rotational wave packet of O2.
A superatom-assembled B8N2 monolayer acting as an electronic sponge for high-capacity anode materials for Na/K-ion batteries
Authors: Shen Kaidong , Cheng Longjiu , Xu Chang
Published: September 2024

The superatomic assembled B8N2 monolayer exhibits remarkably high theoretical storage capacities and low open-circuit voltages, as efficient anode materials in Na/K ions batteries, where the B4 superatomic units act as “electronic sponges”.
Surface modification of paper-based microfluidic devices via initiated chemical vapor deposition
Authors: Bacheller Stacey , Gupta Malancha
Published: September 2024

Paper-based microfluidic devices offer a low-cost platform for biological and environmental detection. This tutorial review shows that initiated chemical vapor deposition can be used to modify these devices with functional polymers.
Improvement of chlorine evolution stability and activity of a RuO2–TiO2/IrO2–Ta2O5 electrode with low iridium content through an alternate coating and thermal decomposition method
Authors: Liu Lin , Dong Tianli , Xin Yuefei , Ye Zongxin , Zhao Pengyi , Gao Wenjing , Tang Huanhuan , Yin Ting , Ren Zhandong , Zhu Yuchan
Published: September 2024

An alternate coating/thermal decomposition method not only improves the chlorine evolution stability and activity of RuO2–TiO2/IrO2–Ta2O5, but also greatly reduces its iridium content.
Unveiling the optoelectronic structure and photovoltaic potential of ZrO2@GO through cosensitization with squaraine dye in DSSC: a computational study
Authors: Fatima Kaniz , Qureashi Aaliya , Nazir Irfan , Zia-ul-Haq  , Ganaie Firdous Ahmad , Manzoor Taniya , Pandith Altaf Hussain
Published: September 2024

The quest to enhance solar cell performance has long been driven by increasing energy demands and environmental concerns, and much progress has been achieved by way of interface modifications.
Expression of concern: Fe3O4/PEG-SO3H as a heterogeneous and magnetically-recyclable nanocatalyst for the oxidation of sulfides to sulfones or sulfoxides
Authors: Mirfakhraei Saeideh , Hekmati Malak , Eshbala Fereshteh Hosseini , Veisi Hojat
Published: September 2024

Expression of concern for ‘Fe3O4/PEG-SO3H as a heterogeneous and magnetically-recyclable nanocatalyst for the oxidation of sulfides to sulfones or sulfoxides’ by Saeideh Mirfakhraei et al., New J. Chem., 2018, 42, 1757–1761, https://doi.org/10.1039/C7NJ02513K.
Asymmetric construction of spirobenzofuran indolinones via a cascade reaction of 3-hydroxyoxindoles with coumarins
Authors: Song Yanji , Zhou Yuqiao , Tan Zheng , Jiao Ziliang , Feng Xiaoming , Liu Xiaohua
Published: September 2024

A series of enantioenriched spirobenzofuran indolinones were afforded via an asymmetric organocatalytic cascade reaction of 3-hydroxyoxindoles with coumarins. Meanwhile, the stereo-determining step of the reaction was disclosed.
Expression of concern: Green synthesis of Pd nanoparticles supported on reduced graphene oxide, using the extract of Rosa canina fruit, and their use as recyclable and heterogeneous nanocatalysts for the degradation of dye pollutants in water
Authors: Hemmati Saba , Mehrazin Lida , Ghorban Hedieh , Garakani Samira Hossein , Mobaraki Taha Hashemi , Mohammadi Pourya , Veisi Hojat
Published: September 2024

Expression of concern for ‘Green synthesis of Pd nanoparticles supported on reduced graphene oxide, using the extract of Rosa canina fruit, and their use as recyclable and heterogeneous nanocatalysts for the degradation of dye pollutants in water’ by Saba Hemmati et al., RSC Adv., 2018, 8, 21020–21028, https://doi.org/10.1039/C8RA03404D.
Zombie diatoms: acoustically powered diatom frustule bio-templated microswimmers
Authors: Ozkan Mehmed C. , McNeill Jeffrey M. , Mallouk Thomas E.
Published: September 2024

The silica-based cell walls harvested from live populations of diatomaceous algae Aulacoseira g. provide a scalable and low-cost platform for fabricating acoustically powered bubble based microswimmers.
Against linkage: A novel generative face anonymization framework with style diversification
Authors: Zhu Mingcheng , He Peisong , Zhang Yuhao , Li Jinghan , Qiu Yupeng
Published: September 2024

With the advent of the digital era, millions of facial images are shared online daily, posing severe privacy threats. Generative face anonymization (GFA) methods generate virtual faces to conceal original identities, protecting sensitive information while preserving utility. However, deep learning based user identity linkage (UIL) methods can link similar faces to the same identity and leverage the linked profiles for malicious purposes, including localization and behaviour prediction. These UIL methods pose a significant challenge to the diversity of virtual faces, a challenge that existing GFA methods have not adequately addressed. To address this research gap, we propose Style Diversification‐based Generative Face Anonymization (SD‐GFA), a framework that generates virtual faces with diverse identities and high visual quality. SD‐GFA features an equalized control module to balance input faces and user‐specified keys, a face generation module with a re‐connection strategy for high‐quality synthesis, and a maximum probability simulation module to enhance diversity. Our experiments demonstrate that SD‐GFA effectively mitigates linkage risk by improving the diversity of virtual faces, while also enhancing their utility and visual quality. This study provides a robust solution to enhance the security of anonymized faces shared on the internet.
Ambulante Durchführung rhinochirurgischer Operationen unter Berücksichtigung des Einsatzes von Nasentamponaden
Authors: Weber Rainer K. , Deitmer Thomas , Löhler Jan , Aletsee Christoph , Baumann Ingo , Betz Christian , Beule Achim , Böscke Robert , Dietz Andreas , Harnischmacher Vanessa , Haubner Frank , Heppt Werner , Hoffmann Anna Sophie , Hoffmann Thomas K. , Hosemann Werner , Kuehnel Thomas , Laudien Martin , Olzowy Bernhard , Seibert Kim-Victoria , Sommer Fabian , Verse Thomas , Wiegand Susanne , Hildenbrand Tanja
Published: September 2024

Hintergrund Die Ambulantisierung rhinochirurgischer Eingriffe wird derzeit intensiv diskutiert und insbesondere von politischer Seite stark propagiert. Viele Fragen zur Stratifizierung in ambulante oder stationäre Durchführung sind unklar. Insbesondere das Vorgehen bei Anwendung von Nasentamponaden ist bisher nicht ausreichend diskutiert.

Material und Methoden Entwicklung einer Checkliste zur ambulanten Durchführung rhinochirurgischer Operationen unter Berücksichtigung der aktuellen Literatur.

Ergebnisse und Schlussfolgerungen Nach umfassender Auswertung der Literatur und Analyse von Risikofaktoren wird eine Liste von stationär durchzuführenden rhinochirurgischen Operationen definiert. Es wird eine Checkliste für die ambulante oder stationäre Durchführung rhinochirurgischer Operationen vorgelegt, die soziale, allgemeine medizinische und spezifische operationsbedingte Gründe berücksichtigt und hierbei die Anwendung von Nasentamponaden einschließt. Sie wird ergänzt durch eine Checkliste, anhand derer Kriterien die Entlassungsfähigkeit von Patienten nach einer ambulant geplanten rhinochirurgischen Operation bewertet wird.
A Review of Third-Trimester Complications in Pregnancies Complicated by Diabetes Mellitus
Authors: Welsey Shaun R. , Day Jessica , Sullivan Scott , Crimmins Sarah D.
Published: September 2024

Pregnancies affected by both pregestational and gestational diabetes mellitus carry an increased risk of adverse maternal and neonatal outcomes. While the risks associated with diabetes in pregnancy have been well documented and span across all trimesters, maternal and neonatal morbidity have been associated with select third-trimester complications. Further, modifiable risk factors have been identified that can help improve pregnancy outcomes. This review aims to examine the relationship between select third-trimester complications (large for gestational age, intrauterine fetal demise, hypertensive disorders of pregnancy, preterm birth, perineal lacerations, shoulder dystocia, and cesarean delivery) and the aforementioned modifiable risk factors, specifically glycemic control, blood pressure control, and gestational weight gain. It also highlights how early optimization of these modifiable risk factors can reduce adverse maternal, fetal, and neonatal outcomes.

Key Points
Effect of Low Dose Glucocorticoid Inhalation on Bronchopulmonary
Dysplasia in Premature Infants
Authors: Li Xiaohua , Liu Heng
Published: September 2024

The aim of the study was to explore the effect of low dose glucocorticoid on
bronchopulmonary dysplasia in premature infants, to provide new ideas for
clinical prevention and cure of bronchopulmonary dysplasia in premature infants.
The 144 cases of premature infants were divided into 72 each: control group and
experimental group. Control group received routine clinical prevention and cure,
while experimental group was received low dose glucocorticoid on the basis of
control group. The serum interleukin-10 (IL-10) , interleukin-8 (IL-8), and
transforming growth factor-1 (TGF-β1) before and after treatment were compared
between two groups. The incidence and severity of bronchopulmonary dysplasia was
compared between two groups. The mechanical ventilation time, oxygen inhalation
time and hospitalization time in two groups were recorded, and the body mass,
head circumference and body length at 30 days after birth were assessed in both
groups. After treatment, the serum IL-10 level in experimental group was
increased and IL-8, TGF-β1 levels were decreased compared with control group (p
<0.05). The incidence rate of bronchopulmonary dysplasia in experimental
group was 13.89% and the disease severity in experimental group was
significantly reduced (p<0.05). Both groups exhibited no notable adverse
reactions (p>0.05). Low-dose glucocorticoids have a significant preventive
and therapeutic effect on bronchopulmonary dysplasia in preterm infants, and
have a high safety, showing high clinical application value for bronchopulmonary
dysplasia in preterm infants.
Ethylene Glycol Mediated, Catalyst-Free Synthesis of Bis(pyrazolo) pyridines and Their Photophysical Studies
Authors: Ramesh Subburethinam , Shanthi Markabandhu , Janani Ravichandran , Puhazhendhi Arulmozhi , Shankar Bhaskaran , Sivalingam Soumya
Published: September 2024

A new hetero-annulation procedure for the selective synthesis of bis(pyrazolo)-fused pyridines using pyrazole-5-amines and aryl glyoxal monohydrate is described. This distinct hetero-annulation, carried out under catalyst-free conditions with ethylene glycol as the medium, illustrates a domino reaction that involves the formation of two C–C bonds and one C–N bond. The photophysical properties of the synthesized derivatives were briefly analyzed. The emission spectra of the derivatives exhibited distinct charge transfer peaks, which depends on the structure of the derivatives. The green metrics calculation for the protocol to quantify the waste, reaction efficiency, and sustainability was evaluated.
Visible-Light Organophotoredox-Catalyzed Phosphonoalkylation of Alkenes via Deaminative Three-Component Radical–Radical Coupling
Authors: Jana Ranjan , Das Subhodeep , Banerjee Amit , Das Pritha
Published: September 2024

Here, we have reported a visible-light-mediated organic photoredox-catalyzed difunctionalization of vinyl arenes via radical–radical coupling. A stabilized benzylic radical at the α-position is generated via the regioselective addition of phosphonyl radical at the β-position of the styrene. Subsequently, benzyl or allyl radical, generated via the deaminative pathway from the Katritzky salt, combines with the α-radical of the styrene to furnish the functionalised C–P and C–C bonds in a single reaction.
A Comparison of Ocular Vestibular Evoked Myogenic Potentials via Audiometric and Nonaudiometric Bone Vibrators
Authors: Garbutt Ruby E. , O'Beirne Greg A. , Maslin Michael R. D.
Published: September 2024

Abstract Background There is limited evidence demonstrating the ability of audiometric bone vibrators to elicit ocular vestibular evoked myogenic potentials (oVEMPs). The RadioEar B71 bone vibrator has insufficient power output to reliably evoke oVEMPs, which
has previously left nonaudiometric and nonmedically approved devices such as the Brüel & Kjær Mini-shaker 4810 as the only feasible alternative. The newer RadioEar B81 model has a higher power output than its predecessor, but evidence for its suitability for eliciting oVEMPs
has so far been mixed. This variability may be due to factors other than simply the power output, such as whether sufficient static force is applied to hold the transducer in place and transfer vibratory energy into the bone. Purpose This study aimed to test the hypothesis
that bone-conducted oVEMPs can be obtained with the B81 that are equivalent to those from the Mini-shaker, the de facto gold-standard transducer for this response, when the outputs of the two transducers are matched and they are coupled with sufficient static force. Research Design oVEMPs
elicited by both transducers were recorded in a counterbalanced within-groups design. Study Sample Sixteen healthy adults (12 female; 22‐47 years) with no history of hearing, balance, or neurological disorders were included in the study. Data collection and analysis One-cycle
alternating tone-burst stimuli at 500 Hz were delivered to the mastoid from each transducer. The vibratory force levels were matched at 127 dB peak-to-peak equivalent force levels, and both were held in place with a static force around 10 N. oVEMP waveforms were gathered
from the contralateral eye using the belly-tendon montage and were assessed for statistical equivalence. Results There was an absence of any statistically significant difference in N10 and N10‐P15 amplitudes in oVEMPs from each transducer. Conclusions Our
results indicate that B81 can elicit oVEMPs with no meaningful differences to those from the Mini-shaker, provided effective stimulus levels are matched and static force is sufficient. Although further work is necessary to investigate equivalence at other stimulus frequencies and stimulation
sites, the results support the use of the B81 to elicit 500Hz oVEMPs at the mastoid in a clinical setting.
Transition-Metal-Mediated Radiohalogenation using Aryl Boron Reagents
Authors: Sutherland Andrew , Burianova Valeria K. , McErlain Holly
Published: September 2024

Biomolecules labeled with radioisotopes of iodine and fluorine play a major role in science and medicine, with a range of applications including molecular imaging of disease, as radiopharmaceuticals for therapy and as tools for drug discovery. Due to the relative stability of Csp2–halogen bonds, radioiodine and radiofluorine labels are commonly incorporated into tracers via arene substitution. The wide availability of aryl boron reagents has led to their use for the development of radioiodination and radiofluorination methods, particularly using transition-metal complexes for accelerated reactions. Here, we review the range of transition-metal-mediated methods that have been developed for radiohalogenation of aryl boron compounds. Applications of these transformations for the preparation of molecular imaging agents and the use of new technologies to advance automated synthesis or high-throughput discovery are also described.

1 Introduction

2 Radioiodination Using Aryl Boron Reagents

2.1 Applications of Copper-Mediated Radioiodination Reactions

3 Radiofluorination Using Aryl Boron Reagents

3.1 Radiofluorination Using Palladium, Nickel and Silver Complexes

3.2 Radiofluorination Using Copper Complexes

3.3 Applications of Copper-Mediated Radiofluorination Reactions

3.4 New Technology for Copper-Mediated Radiofluorination Reactions

4 Conclusions
Management of Compound Depressed Fractures over Venous Sinuses
Authors: Elbaroody Mohammad , Marei Ahmed A. , Sawy Karim Fathy , Mahmoud Alaa Eldin , Amin Mark Charl , Elkatatny Amr A.M. , badea Hazem Abd Al
Published: September 2024

Objective The aim of this study was to report our experience in the surgical treatment of compound depressed fractures over the venous sinuses with special highlights on the prediction and dealing with intraoperative sinus injury.

Materials and Methods We conducted a retrospective review of all patients who underwent surgery for compound depressed fractures overlying the dural venous sinuses in our hospital between January 2019 and December 2021.

Results A total of 34 patients were included in our study. The mean age of the patients was 19.85 years, most of our patients were males 27 (79.4%), and isolated head trauma was the most common mode of trauma (76.5%). The superior sagittal sinus (SSS) was distinguished as the most commonly involved venous sinus below the fractures in 28 patients (82.4%). An intraoperative tear in the sinus was found in 17 patients (50%), which was easily controlled with different methods. In two patients who had a severe head injury with a Glasgow Coma Scale (GCS) score of ≤8 associated with a fissure fracture crossing the sinus, there was a complete tear of the sinus followed by massive bleeding, which required sinus ligation. We lost both of them in following days.

Conclusion In experienced tertiary neurotrauma centers, compound depressed fractures over the venous sinuses should be surgically elevated in most cases, taking into consideration that bleeding from the sinus can be controlled in most cases, and complete tear of the sinus with massive bleeding is the least scenario faced in reality and is usually associated with a severe head injury. If expert opinion favors the conservative approach, then close follow-up for months is recommended due to the high possibility of sinus thrombosis and intracranial hypertension, especially in children.
Does the environmental impact of banks affect their financial performance?
Authors: Bressan Silvia
Published: September 2024

We empirically study the environmental impact of banks, i.e., the negative externality on the environment and society deriving from the use of a natural resource or the emission of a pollutant. We find that environmental “impact ratios”, that is, environmental damage costs in proportion to total revenues are negatively correlated with bank profitability. Furthermore, banks with a stronger impact on the environment are valued less by equity market investors and pay less cash to shareholders. Among environmental categories, potential damage from greenhouse gas emissions or waste seems to be especially severe. We provide important insights for banks’ environmental management. If bankers can address businesses and practices to be more renewable and lower in their emissions, they could improve both the operating and the market performance. Thus, firms would be financially more stable and could react smoothly to the recent introduction of stricter and onerous environmental regulations.
TECXY simulations of the power exhaust in the multi-impurity plasma of DTT reactor
Authors: Grzybicka N. , Chmielewski P. , Innocente P.
Published: September 2024

Reduction of the heat load to plasma-facing components is a crucial problem for future fusion reactors like Divertor Test Tokamak (DTT). Mitigation of the power load via increased plasma radiation with the use of puffed ions of impurities would be one way to mitigate power in the scrape-off layer. This paper presents a numerical investigation of the impact of seeded impurities on the radiation pattern and the power load to the divertor plates of the high-field DTT reactor in the single null (SN) configuration. The simulations have been done with the use of the TECXY code, which solves multi-species plasma transport equations for multiple impurity species simultaneously and all associated ionization stages in a two-dimensional poloidal geometry. TECXY represents the model of plasma transport in the scrape-off layer region by a classical set of transport equations of multi-species plasma derived by Braginskii. The paper aims to compare the mitigation capabilities of neon and argon impurities seeded in the plasma of the DTT device and to obtain a significant energy flux reduction to the target plate at the smallest possible impurity concentration. Performed investigations showed the effects of neon and argon impurities seeding separately for constant electron density at the separatrix. It has been found that the decrease in electron temperature on the divertor plates up to 3 eV at the outer and the inner divertor plates and the peak power load below 15 MW m−2 at the outer divertor plate can be achieved with argon seeding and much lower impurity concentration than that in the case of neon impurity seeding. Studies have shown the complexity of the effect of neon and argon impurities on the boundary plasma. It was found that the reduction of temperature and the power on both divertor plates was the most effective for the high upstream plasma densities. The results show also that diffusive perpendicular transport strongly affects impurity radiation and thus plasma condition at divertor plates.
Long-term stability of squeezed light in a fiber-based system using automated alignment
Authors: Nakamura Tomohiro , Nomura Takefumi , Endo Mamoru , Sakaguchi Atsushi , Ruofan He , Kashiwazaki Takahiro , Umeki Takeshi , Takase Kan , Asavanant Warit , Yoshikawa Jun-ichi , Furusawa Akira
Published: September 2024

Providing a cloud service for optical quantum computing requires stabilizing the optical system for extended periods. It is advantageous to construct a fiber-based system, which does not require spatial alignment. However, fiber-based systems are instead subject to fiber-specific instabilities. For instance, there are phase drifts due to ambient temperature changes and external disturbances and polarization fluctuations due to the finite polarization extinction ratio of fiber components. Here, we report the success of measuring squeezed light with a fiber system for 24 h. To do this, we introduce stabilization mechanics to suppress fluctuations in the fiber system and an integrated controller to automatically align the entire system. The squeezed light at a wavelength of 1545.3 nm is measured every 2 min, where automated alignments are inserted every 30 min. The squeezing levels with an average of −4.42 dB are recorded with an extremely small standard deviation of 0.08 dB over 24 h. With the technologies developed here, we can build complicated optical setups with the fiber-based system and operate them automatically for extended periods, which is promising for cloud service of quantum computation.
Dynamic event-triggered quantized secure output consensus of heterogeneous multi-agent systems under DoS attacks
Authors: Deng Furong , Xu Chengjie , Guan Zhi-Hong , Chen Gang
Published: September 2024

This paper investigates secure output consensus problem of heterogeneous multi-agent systems (HMASs) under denial-of-service (DoS) attacks. First, an adaptive dynamic compensator depending on local measurement information is designed for tracking the signal of the virtual exosystem. Second, for mitigating network communication load, a novel adaptive control protocol is developed by introducing dynamic event-triggered control and quantized control strategies. Moreover, Zeno behavior can be eliminated under the proposed scheme. Third, the secure output consensus of HMASs under DoS attacks can be guaranteed by satisfying the designed sufficient conditions. Finally, simulation is shown to verify reliability of the proposed control protocol and theory.
Spectral decomposition for collective Thomson scattering based on an improved genetic algorithm
Authors: Zhang Jingshuo , Lan Ting , Zeng Qingbin , Wu Zhengwei , Zhuang Ge , Xie Jinlin
Published: September 2024

Collective Thomson scattering (CTS) is a diagnostic technique that obtains ion temperature and ion composition of plasma by spectral decomposition from scattering spectra. Bayesian estimation and least squares fitting are usually applied in this spectral decomposition process. Nevertheless, these spectral decomposition methods strongly rely on measurements of other diagnostic systems, and the measurement errors of other systems would influence the spectral decomposition results. In this article, an improved genetic algorithm is applied to decompose the scattering spectra of CTS. By analyzing the sensitivity of plasma parameters, the width and slope of the scattering spectrum are found to be strongly associated with ion temperature. Based on this correlation relation, a new fitness function is designed to provide a more precise estimation of ion temperature. Meanwhile, adaptive crossover and mutation operators are introduced to solve the premature convergence problem. This improved genetic algorithm with the new fitness function can obtain a more precise ion temperature from scattering spectra of CTS and does not rely on the measurement of other diagnostic systems, which has an extensive application prospect in data processing of CTS.
Study on dynamic imbibition mechanism of matrix-fracture in three dimensions tight sandstone based on level set method
Authors: Fu Hongtao , Song Kaoping , Zhao Yu , Liang Lihao , Song Qingjia , Guo Hu
Published: September 2024

Tight oil reservoirs require fracturing techniques to create complex fracture networks for efficient development. It is frequently accompanied by a dynamic matrix-fracture imbibition process, promoting enhanced recovery. At present, the mechanism of three dimensions (3D) matrix-fracture dynamic imbibition at the pore scale has not been fully elucidated. In this paper, the dynamic imbibition process of oil-water two phases in matrix-fracture was simulated based on the Navier–Stokes equations, and the level set method was used to capture the real-time interfacial changes between the two phases. It was found that during matrix-fracture dynamic imbibition process, oil-phase droplets in a single pore remain in the pore mainly due to the “stuck” effect. Cluster residual oil in the pore space is mainly retained due to the “flow around” effect. Continuous residual oil in the deeper regions of the matrix is due to insufficient capillary force. Water phase in the micro-confinement space of a tight reservoir intrudes into the pore space along the pore corners, forming the “fingering” phenomenon is beneficial for enhancing the efficiency of micro-dynamic imbibition. It differs from cognition obtained in the micro-view space during conventional water flooding. The enhancement of imbibition efficiency is often accompanied by the occurrence of fluctuations in the average pressure within the matrix. Therefore, a method involving impulse type of high-frequency and short-period for supplemental energy and imbibition is suggested to enhance recovery in tight sandstone reservoirs. This study reveals the detailed mechanisms of oil-water two-phase transport at different stages in the dynamic imbibition process and holds significant guiding implications for enhancing recovery in this type of reservoirs.
Testing the optical components for the National Ignition Facility time-resolved soft x-ray opacity spectrometer (OpSpecTR)
Authors: Wallace M. S. , Peterson A. E. , Opachich Y. P. , Dutra E. C. , Knight R. A. , Heinmiller J. M. , Dzenitis D. M. , Posadas R. , Miller A. G. , Moy K. , Urbatsch T. J. , Johns H. M. , Heeter R. F. , Perry T. S.
Published: September 2024

Opacity measurements are being carried out at the Z-facility at Sandia National Laboratories and at the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory. The current soft x-ray Opacity Spectrometer (OpSpec) used on the NIF uses two elliptically bent crystals in time-integrated mode on either an image plate or a film. Plans are under way to expand these opacity measurements into a mode of time-resolved detection, called OpSpecTR. Previously, considerations for the available hCMOS detector size and photometrics led to a crystal geometry redesign and the use of a grazing angle x-ray mirror. The mirror acts as a low-pass x-ray energy filter, reducing the contribution of higher energy x rays. The first tests of the mirror and the crystal for OpSpecTR are presented here. The size of the mirror reflection and the reflectivity is tested using a Manson x-ray source. The mirror coupled with the new elliptical crystal shape demonstrates OpSpecTR’s spectral coverage. The results from the x-ray optics performance testing are shown along with the intended design.
Data-driven discrete fractional chaotic systems, new numerical schemes and deep learning
Authors: Wu Guo-Cheng , Wu Zhi-Qiang , Zhu Wei
Published: September 2024

Parameter estimation is important in data-driven fractional chaotic systems. Less work has been reported due to challenges in discretization of fractional calculus operators. In this paper, several numerical schemes are newly derived for delay fractional difference equations of Caputo and Riemann–Liouville types. Then, loss functions are constructed and unknown parameters of the discrete fractional chaotic system are estimated by a neural network method. Parameter estimation results demonstrate high accuracy compared with real values. Robust analysis is provided under different noise levels. It can be concluded that this paper provides an efficient deep learning method based on fractional discrete-time systems.
Quasi-one-dimensional non-equilibrium method for shock tube and stagnation line flows
Authors: Clarke J. , Brody S. , Steer J. , McGilvray M. , Di Mare L.
Published: September 2024

Shock tube experiments are used to investigate non-equilibrium thermochemistry and radiative processes in reacting gas hypersonic flows. Boundary layer and shock structure are known to influence the spatial variation of the test slug state properties. This work derives and validates a novel method for viscous, quasi-one-dimensional, non-equilibrium flow in a shock tube assuming constant shock speed. The proposed method fully resolves the shock structure. Mirels' estimate for boundary layer growth around the test slug determines the dilation rate at the centerline. This, along with relevant boundary conditions, appropriately models core flow in a shock tube. The flow equations are discretized by finite differences on a staggered grid. The resulting highly non-linear set of algebraic equations is solved by Newton iterations. The Jacobian matrix is block tridiagonal with a Schur complement, allowing efficient inversion. This culminates in a unique and computationally efficient quasi-one-dimensional method offering improved modeling of the physical characteristics of shock tube experiments. Results of a 3 km/s, 66.6 Pa argon test case solved by a viscous, axisymmetric Navier–Stokes solution had agreement with the proposed method in temperature and pressure profiles to within 2% and post-shock velocity to within 15%. Reacting gas shock tube experiments in synthetic air and synthetic Titan atmospheres were analyzed. Radiance values in the non-equilibrium and equilibrium regions were compared under various assumptions for the shock structure and radial velocity distribution. These results highlight the necessity of a dedicated shock tube solver when analyzing shock tube thermochemistry, particularly when determining reaction rates and relaxation parameters.
A venting resonator emitting monochromatic periodic traveling waves in dispersive media
Authors: Jain U.
Published: September 2024

Dynamically stable traveling periodic waves are notoriously difficult to realize experimentally. Manifestations of such waves inherently become unstable in any dispersive medium, whether it be at continuum length scales in fluid mechanics, in electrodynamics, or in nonlinear optics. Here, a simple experimental system is proposed where Stokes waves are emitted from a resonator whose cavity accommodates standing waves of same wavelength that is emitted out. A single characteristic wavelength is found for each driving frequency despite the coexistence of standing and traveling waves, external noise, and potentially parasitic reflections. The system's response is shown to be reliable at very small values of quality factor. A unique utility of this model system is suggested in that such a venting resonator can be used as an inhibitor of modulation instability in dispersive medium where an engineering application demands stable periodic traveling waves. Some parallels are drawn with other unbounded resonators found in society, whereby their leakiness is central to their application, such as the role of air-filled cavity to achieve impedance matching in stringed musical instruments, or energy harvesting from oscillating fluid columns in nature.
Simultaneous vector magnetometry based on fluorescence polarization of NV centers ensemble in diamond
Authors: Li Mingxin , Yuan Heng , Fan Pengcheng , Wang Sixian , Shen Jihongbo , Xu Lixia
Published: September 2024

The nitrogen-vacancy (NV) centers ensemble has extensive application prospects in vector-magnetic-field measurement due to its accurate and fixed spatial orientations along the crystallographic axes of diamonds. However, to address signals of NV centers along all four axes, a large bias magnetic field sufficient to spectrally separate their resonances is typically inevitable, which may affect the magnetic substance under test and require multiple-frequency microwaves to interrogate signals of the four axes. Here, we demonstrate an NV-based simultaneous vector magnetometer that works at a bias field as low as just separating the resonant peaks of |ms=±1 states and utilizes a single-frequency microwave. By simultaneously detecting the fluorescence at specific optical polarization angles in three orthogonal directions and determining the transformation matrix in advance, all the Cartesian components of the magnetic field under test are distinguished. The experimentally achieved magnetic-field sensitivity is 63 nT/Hz, and the bias field is reduced to around 11 Gauss (still reducible by narrowing the linewidth) in ambient conditions. The proposed methods dramatically reduce the bias field for NV-based simultaneous vector magnetometers and potentially expand their applications in biological science, materials science, and industrial noninvasive detection.
Application of cross-channel multiscale permutation entropy in measuring multichannel data complexity
Authors: Li Weijia , Shen Xiaohong , Li Yaan , Chen Zhe , Shen Yupeng
Published: September 2024

Entropy is a pivotal concept in nonlinear dynamics, revealing chaos, self-organization, and information transmission in complex systems. Permutation entropy, due to its computational efficiency and lower data length requirements, has found widespread use in various fields. However, in the age of multi-channel data, existing permutation entropy methods are limited in capturing cross-channel information. This paper presents cross-channel multiscale permutation entropy algorithm, and the proposed algorithm can effectively capture the cross-channel information of multi-channel dataset. The major modification lies in the concurrent frequency counting of specific events during the calculation steps. The algorithm improves phase space reconstruction and mapping, enhancing the capability of multi-channel permutation entropy methods to extract cross-channel information. Simulation and real-world multi-channel data analysis demonstrate the superiority of the proposed algorithm in distinguishing different types of data. The improvement is not limited to one specific algorithm and can be applied to various multi-channel permutation entropy variants, making them more effective in uncovering information across different channels.
Lattice Boltzmann modeling of natural circulation loop with emphasis on non-Boussinesq mechanism
Authors: Zhang Jinsong , Wu Yongyong , Gui Nan , Liu Zhiyong , Yang Xingtuan , Tu Jiyuan , Jiang Shengyao
Published: September 2024

The natural circulation loop is crucial for the safe and stable operation of nuclear reactors and other applications. Traditional numerical algorithms, based on the Boussinesq approximation, have limitations when dealing with large temperature differences and density disparity, and they do not fully address fluid compressibility. This paper adopts the decoupled and stabilized lattice Boltzmann method (DSLBM) with a non-Boussinesq algorithm to study the natural circulation loop. The DSLBM provides a detailed flow description under large temperature and density differences, incorporating the pseudopotential multiphase model, temperature equation, and state equation, without relying on assumptions. The study examines the loop's performance under various temperature differences, central height differences, and heating source lengths, focusing on mass flow rate, driving head, and heating power. It reveals the energy performance, flow characteristics, and heat transfer properties of the loop, highlighting the physical mechanisms involved. Comparison with the empirical formulation of the incompressible equation from the theoretical aspect shows that when the temperature difference coefficient is lower than 0.15, the two methods are not much different from each other. When the temperature difference coefficient reaches 0.2, 0.3, and 0.4, the difference between the two methods is 9.47%, 19.11%, and 42.64%, respectively. Consequently, the Boussinesq approximation can be compensated by DSLBM, which proves the value of the application of the algorithm in exploiting the compressibility of fluids. The dimensionless fitting correlation with greater universality is obtained, which helps to predict the properties of the natural circulation loop with varying temperature differences, friction coefficients, and geometric structures. The research in this paper will lay the foundation for optimizing the system design of the natural circulation loop and improving energy utilization efficiency.
A note on Taylor–Couette style flows with two parallel inner cylinders
Authors: Carlotti P.
Published: September 2024

The flow in the gap between an inner and outer cylinder presents a variety of regimes, which are well explored. In the present work, we attempt to explore a more complex flow, with two parallel co-rotating inner cylinders. The rationale behind this arrangement was the following: in terms of base two-dimensional flow, close to each inner cylinder, the base flow resembles a laminar Couette flow, and close to the outer cylinder, the flow may again resemble a Couette flow, with the two inner cylinders being seen as a single source of momentum, while in the middle point between the inner cylinder, there is stagnation saddle point with two incoming and two out coming streamlines, creating a zone with a high shear where interaction of Taylor–Couette style rolls is expected. The experiment allowed to identify six regimes: for Re<50, presence of the base two-dimensional flow; for 50<Re<70, the first regime of steady rolls, equivalent to Taylor vortices; for 70<Re<110, vortices become unsteady; for 110<Re<170, in the stretched zone, the flow is unsteady while the same fluid parcels are then stabilized when leaving the stagnation point region and slowed down toward the outer wall; when Re>170, there is the onset of turbulent rolls, with loss of spatial periodicity and apparition of turbulence; and finally a second type of steady rolls occurs for a sudden start of cylinders and 50<Re<60.
Thermal performance analysis of sinusoidal corrugated channels: A comparative study of thermo-hydraulic and entropy generation
Authors: Al-Daamee Fatimah Q. , Hamza Naseer H. , Khan M. Ijaz , Al-Dossari Mawaheb
Published: September 2024

The physical properties of working fluids—in terms of the Prandtl number—play a crucial role in determining their thermal performance in the internal flow, especially their viscosity. This study first considers the thermo-hydraulic and entropy generation of a sinusoidal corrugated channel in two configurations: symmetrical (raccoon) and asymmetrical (serpentine). Results are presented for different ranges of operating parameters, such as 100≤Re≤700 and 0.72≤Pr≤90, and for geometrical parameters such as the wave amplitude-to-wavelength ratio 0.2≤α≤0.6. In addition, the results of the two channels were compared with each other's and with the straight channel. Control transport equations are solved using finite element methods. It was found that the flow inside the wavy channels generated re-circulatory reigns, and their size was affected by the wave parameters as well as the Reynolds number. Also, employing high values of Pr extremely enhanced the heat transfer rate (HTR) of the wavy channels over the straight for all values of α and for both raccoon and serpentine channels. In addition, the results indicated that raccoon channels have higher HTR and performance factor compared to the serpentine channel. Finally, the thermal entropy generation dominated over the viscous entropy generation and its decrease with both Reynolds number and Prandtl number for raccoon and serpentine channels. This study focused on the heat transfer enhancement of the corrugated channels due to their importance in many industrial applications where the heat dissipation is critical to their work, including heat exchangers and heat sinks. Thus, the current numerical simulation primarily suggests utilizing the raccoon channel over the serpentine one, due to its higher thermal performance and nearly the same total entropy generation.
Review on spray characteristics of liquid–liquid injectors in liquid rocket engines
Authors: Xie Yu , Zhang Jiaqi , Sun Mingbo , Wu Jiping , Li Peibo , An Bin , Liang Changhai , Wang Taiyu , Cheng Peng , Chen Jikai , Wang Jiaoru , Li Menglei
Published: September 2024

Impinging-jet injectors, liquid–liquid coaxial swirl injectors, and liquid–liquid pintle injectors are representative liquid–liquid injectors in liquid rocket engines (LRE). For these liquid–liquid injectors, the atomization processes all involve the liquid impingement, including jet–jet, sheet–sheet, and jets/sheet–sheet impingement, respectively. After impingement, a liquid sheet forms and fragments. Based on these similarities, reviewing published literature on the spray characteristics of these three liquid–liquid injectors in LRE is necessary and will facilitate the investigation of spray characteristics of liquid–liquid pintle injectors to meet the progress of variable-thrust LRE. This review covers the following aspects of these injectors: basic spray morphology, liquid sheet characteristics and disintegration mechanisms, and atomization characteristics. For impinging-jet injectors, rim instability and impact wave play crucial roles in spray morphology and disintegration. Jet Weber number is of great importance for liquid sheet breakup length and mean droplet diameter. In the case of liquid–liquid coaxial swirl injectors, the overall spray morphology is similar to that of pressure swirl injectors, but it may feature two separate liquid sheets. The recess length strongly influences spray morphology, spray angle, breakup length, and Sauter mean diameter. Liquid–liquid pintle injectors can be simplified to injection element, in which the spray morphology resembles a cloak-like shape. In a complete pintle injector, the spray forms a conical liquid sheet. Momentum ratio proves to be the most significant parameter for predicting spray angle. Although the review indicates substantial progress has been made in understanding spray characteristics of liquid–liquid injectors, there remain several shortcomings that require further research, particularly for pintle injectors, which can be learned from the other two injectors.