bluuebunny/crossref_metadata_2025 huggingface dataset:
The Impact of COVID-19 Fatigue and Pandemic Burnout alongside Academic Stress on the Gingival Health of Dental Students
Authors: Ali Jameela , Al-ruwais Mathayel , Jawa Shahad , Ahmed Yara , Babatin Wafaa , Abdelrasoul Mohammed Roshdy
Published: May 2024

Objectives Stress has delirious effects on gingival health. Dental students experience higher levels of academic stress during their education that requires clinical and patient management skills. Coronavirus disease 2019 (COVID-19) fatigue is a type of chronic stress that has put the population under high stress for an extended period of time. This study aimed to assess the impact of pandemic burnout and fatigue on the gingival health of academically stressed dental students.

Materials and Methods This study compared junior (n = 20) and senior (n = 20) year dental students undergoing their final year exams. Gingival health was assessed by plaque index (PI), gingival index (GI), and modified papillary bleeding index (MPBI). Academic stress was measured by the dental environmental stress questionnaire, while COVID-19 burnout was judged by COVID-19 student stress questionnaire (CSSQ).

Statistical Analysis Quantitative data were expressed as mean, standard deviation and median Student's t-test was used to compare two categories for normally distributed quantitative variables, while significance of the obtained results was judged at the 5% level.

Results Gingival health evaluation revealed no significant differences in GI and PI; however, MPBI in juniors was more significant (p = < 0.001). Academic stress was significantly higher among seniors (p = 0.001); nevertheless, CSSQ showed low levels of stress toward the pandemic with no significant differences.

Conclusion Gingival diseases are multifactorial in nature; stress is a biologically influencing factor as well. Despite the evidence of high academic stresses among dental students, the impact of COVID-19 fatigue on gingival health was inconclusive and slight differences were found between junior and senior-year dental students.
Ten-Year Cardiovascular Risk Estimation through the Framingham Risk Score among Commercial Motor Vehicle Drivers with High and Low Risk of Obstructive Sleep Apnea
Authors: Sharifi Navid , Najafi Arezu , Alemohammad Zahra Banafsheh , Sadeghniiat-Haghighi Khosro
Published: May 2024

Objective Obstructive sleep apnea (OSA) and cardiovascular disease (CVD) are both major medical causes of road accidents among commercial motor vehicle (CMV) drivers. The present study aimed to determine the association of the ten-year risk of developing CVD and other cardiac risk factors with the risk of developing OSA among apparently healthy CMV drivers.

Materials and Methods The present cross-sectional study was conducted on 315 male CMV drivers. Demographic characteristics were collected, and the Epworth Sleepiness Scale (ESS), the Snoring, Tiredness, Observed Apnea, High Blood Pressure, Body Mass Index (BMI) > 35 kg/m2, Age > 50 Years, Neck Circumference > 40 cm, and Male Gender (STOP-Bang) questionnaire, and International Physical Activity Questionnaire-Short Form (IPAQ-SF) were filled out, and the ten-year CVD risk was calculated through the Framingham Risk Score (FRS) for each individual. Laboratory tests also were performed. The participants were divided into two groups based on the STOP-Bang score and FRS, and other CVD risk factors were compared, accordingly. The Chi-squared test, the Student t-test, analysis of variance (ANOVA), and logistic regression were used for the analysis.

Results The mean age of the drivers was of 45.57 (range: 30 to 70) years. In the univariate analysis, the mean age, years of driving experience, FRS, vascular age, blood pressure, diabetes mellitus, metabolic syndrome, ESS score, BMI, and circumference of the waist and hip presented a significant association with STOP-Bang score ≥ 3 (p < 0.05). The metabolic equivalents of task (METs) for total physical activity and walking (min/week), time spent sitting (h/day), lipid profiles, smoking history, vehicle type, and shift type were statistically similar in both groups. In the multivariate analysis, a high risk of OSA was independently associated with higher FRS (odds ratio: 1.92; p < 0.001).

Conclusion The STOP-Bang score presented a direct correlation with the estimated ten-year CVD risk in CMV drivers. The high risk of developing OSA among CMV drivers is accompanied by higher CVD risk factors such as old age, diabetes, hypertension, BMI, and waist and hip circumference. The FRS was statistically higher in CMV drivers with high OSA risk.
Perianal Fistulizing Crohn's Disease: Outcomes of Surgical Repairs and Current State of Stem Cell-Based Therapies
Authors: Dawes Aaron J. , Lightner Amy L.
Published: May 2024

Perianal fistulizing Crohn's disease is one of the most disabling phenotypes of Crohn's disease, due to the severe impairment in quality of life including social and personal wellbeing. A multimodal approach with patient-tailored care is the key to optimal management of this condition. Medical therapy is needed to optimize the luminal disease, and surgical intervention is required to control any associated perianal sepsis and attempt palliative or definitive fistula repair. While several medical and surgical options are available, the majority of patients continue to have symptomatic disease. Fortunately, this continues to drive novel innovations which are revolutionizing the treatment and outcomes of perianal fistulizing Crohn's disease. However, there continues to be a need for randomized trials and consistent metrics utilized for classification and treatment outcomes in order to accurately describe optimal treatment outcomes.
Scaling photonic integrated circuits with InP technology: A perspective
Authors: Wang Yi , Jiao Yuqing , Williams Kevin
Published: May 2024

The number of photonic components integrated into the same circuit is approaching one million, but so far, this has been without the large-scale integration of active components: lasers, amplifiers, and high-speed modulators. Emerging applications in communication, sensing, and computing sectors will benefit from the functionality gained with high-density active–passive integration. Indium phosphide offers the richest possible combinations of active components, but in the past decade, their pace of integration scaling has not kept up with passive components realized in silicon. In this work, we offer a perspective for functional scaling of photonic integrated circuits with actives and passives on InP platforms, in the axes of component miniaturization, areal optimization, and wafer size scaling.
Enhanced spectrum prediction using deep learning models with multi-frequency supplementary inputs
Authors: Xing Xiaohua , Ren Yuqi , Zou Die , Zhang Qiankun , Mao Bingxuan , Yao Jianquan , Xiong Deyi , Wu Liang
Published: May 2024

Recently, the rapid progress of deep learning techniques has brought unprecedented transformations and innovations across various fields. While neural network-based approaches can effectively encode data and detect underlying patterns of features, the diverse formats and compositions of data in different fields pose challenges in effectively utilizing these data, especially for certain research fields in the early stages of integrating deep learning. Therefore, it is crucial to find more efficient ways to utilize existing datasets. Here, we demonstrate that the predictive accuracy of the network can be improved dramatically by simply adding supplementary multi-frequency inputs to the existing dataset in the target spectrum predicting process. This design methodology paves the way for interdisciplinary research and applications at the interface of deep learning and other fields, such as photonics, composite material design, and biological medicine.
Fuzzy logic-driven genetic algorithm strategies for ultrasonic welding of heterogeneous metal sheets
Authors: Amale Ashvin , Singholi Ajay K. S. , P Satishkumar , Giri Jayant , Albaijan Ibrahim , Guru Ajay
Published: May 2024

There are a lot of problems with the conventional fusion welding process, so ultrasonic welding has been used for about 20 years and has helped a lot of manufacturing industries, including aviation, medicine, and microelectronics. Ultrasonic welding takes less than one second, making it suitable for mass production. Poor weld quality and joint strength are common issues that industries encounter as a result of this process. Actually, the success and quality of the welding are determined by its control parameters. This research examines the impacts of weld time, vibrational amplitude, and weld pressure on the welding of 0.6 mm thick sheets of two different metals, specifically copper and aluminum (AA2024). Responses, including tensile shear stress, weld area, and T-peel stress, are acquired through experiments that follow a full factorial design including four replicas. The highest recorded tensile shear stress was 4.34 MPa, the maximum weld area measured was 63.6 mm2, and the peak T-peel stress reached 1.22 MPa. A second-order non-linear regression model was constructed using all of these data points, which related the responses to the predictors. Due to the importance of quality in the production sector, the process parameters were determined by the combination of genetic algorithm (GA) and fuzzy logic (FL) approaches. The impact of the weld zone temperature on various quality characteristics has been investigated through experiments. It has been noted from the confirmatory test that FL produces superior output outcomes compared to the genetic algorithm, with FL achieving a fuzzy multi-performance index of 0.94 compared to 0.61 for GA. By conducting microstructural analysis, weld quality levels, including “under-weld,” “good weld,” and “over-weld,” were established.
An investigation on the jet formation and penetration characteristics of the CuCoCrFeNi high-entropy alloy liner
Authors: Li Rong-Xin , Wang Rui-Qi , Tian Quan-Wei , Zhong Xi-Ting , Song Jia-Xing , Huang Jun-Yi , Wu Jia-Xiang , Li Yu-Chun
Published: May 2024

This study performs a series of mechanical tests, quasi-static and dynamic, on CuCoCrFeNi high-entropy alloys (HEAs) using an experimental setup to explore the performance of Cu-based HEAs in shaped charges. It derives the parameters for the Johnson–Cook constitutive model through fitting. A static penetration test is conducted with a small cone angle and a thin-walled liner. The outcomes are then compared to simulation data generated by AUTODYN software. They indicated that the CuCoCrFeNi HEA liner can produce a shaped-charge jet that achieves both penetration and reaming effects when driven by explosives. In a C45 steel target, the diameter of the penetration hole is 46.43% of the charge diameter. The experimental findings align closely with the simulations, indicating discrepancies of less than 12.13% in the diameters of the penetration holes and ∼2.56% in penetration depths. Hence, the numerical simulation approach and its parameters can be utilized to investigate the penetration characteristics of Cu-based HEA jets, providing a groundwork for future optimization of HEA-shaped charge designs.
Structural framework of the Caswell Sub-basin, North West Shelf, Australia
Authors: Tsutsui Kosuke , Holford Simon , Bunch Mark , King Rosalind , McClay Ken , Schofield Nick
Published: May 2024

The Caswell Sub-basin, situated within the Browse Basin in the North West Shelf constitutes one of Australia’s primary hydrocarbon producing regions, with notable gas-condensate producing fields including Ichthys and Prelude. Jurassic syn-rift sandstones are extensively distributed across the basin and serve as one of the major reservoirs. However, reservoir sequences are typically intensely faulted and exhibit heterogeneity in thickness and lithofacies, with some areas experiencing localised erosion on uplifted fault blocks (e.g. Northern Caswell Sub-basin). Hence, understanding the nature of the 3D fault patterns and their growth history is crucial for evaluating the reservoir characteristics for field development and additional exploration activities. This study, therefore, aims to evaluate the structural framework and the tectonic evolution of the Caswell Sub-basin. Detailed structural interpretation of Paleozoic and younger sequences was conducted using multiple 3D seismic datasets extending over Ichthys, Prelude, Lasseter, and Crown fields. Our study focuses mainly on Mesozoic faulting patterns and kinematics evaluated from interpreted structural maps, thickness changes of each stratigraphic interval and fault throw profiles of major bounding faults. The extensional phase during the Early–Middle Jurassic triggered the development of NE–SW trending faults and the deepening of the Brewster Graben. While, from the Late Jurassic to the Early Cretaceous, the development of E–W trending faults in the north of the Crown and Lasseter fields indicate a shift in the regional stress regime. We highlight the importance of evaluating the structural linkage from basement to cover sequences to achieve a comprehensive understanding of reservoirs and associated petroleum systems.
Ultrapotent influenza hemagglutinin fusion inhibitors developed through SuFEx-enabled high-throughput medicinal chemistry
Authors: Kitamura Seiya , Lin Ting-Hui , Lee Chang-Chun David , Takamura Akihiro , Kadam Rameshwar U. , Zhang Ding , Zhu Xueyong , Dada Lucas , Nagai Emiko , Yu Wenli , Yao Yao , Sharpless K. Barry , Wilson Ian A. , Wolan Dennis W.
Published: May 2024

Seasonal and pandemic-associated influenza strains cause highly contagious viral respiratory infections that can lead to severe illness and excess mortality. Here, we report on the optimization of our small-molecule inhibitor F0045(S) targeting the influenza hemagglutinin (HA) stem with our Sulfur-Fluoride Exchange (SuFEx) click chemistry–based high-throughput medicinal chemistry (HTMC) strategy. A combination of SuFEx- and amide-based lead molecule diversification and structure-guided design led to identification and validation of ultrapotent influenza fusion inhibitors with subnanomolar EC50cellular antiviral activity against several influenza A group 1 strains. X-ray structures of six of these compounds with HA indicate that the appended moieties occupy additional pockets on the HA surface and increase the binding interaction, where the accumulation of several polar interactions also contributes to the improved affinity. The compounds here represent the most potent HA small-molecule inhibitors to date. Our divergent HTMC platform is therefore a powerful, rapid, and cost-effective approach to develop bioactive chemical probes and drug-like candidates against viral targets.
Metaphors of love before and after marriage in proverbs and anti-proverbs
Authors: Litovkina Anna T.
Published: May 2024

In the present chapter I am going to discuss the ways how love after marriage is viewed and conceptualised in the body of
Anglo-American proverbs and anti-proverbs (or proverb transformations), as well as in proverbs from around the world. My discussion is
organised in two parts. While in the first part of the chapter I treat the paremiological issue of the metaphorical nature of
proverbs, in the second part I address the relation between love and marriage in proverbs from around the world and Anglo-American
anti-proverbs. I treat various metaphors of love which lead one to getting married (e.g., love is folly), as well as some
metaphors of love after marriage (e.g., love is war).
Stuttering in two languages
Authors: Medina Angela M. , Müller Nicole , Ball Martin J.
Published: May 2024

The purpose of this study was to describe the linguistic resources used by four Spanish-English
speaking bilingual males who stutter to convey their attitudes and experiences with bilingual stuttering. Participants
were 16, 28, 29, and 63 years of age. Analytic tools grounded in Systemic Functional Linguistic theory, namely those
based on experiential meaning and appraisal, revealed how participants structured their talk to emphasize details and
experiences of significance. Aspects of being a second language learner were described as a facilitator and a
hindrance to fluency, while stuttering was reported as having both a positive and negative impact on language
learning. Characteristics of Spanish grammar such as high frequency of vowel-initial words and morphosyntactic
structure were described as barriers to fluent speech.
Variation in phonological and morphosyntactic development in multilingual pre-schoolers
Authors: Barrière Isabelle , Shafer Valerie , van der Feest Suzanne
Published: May 2024

The present chapter investigates how the quantity of input and the linguistic characteristics of
the Heritage Language (HL), Spanish or Russian, impact the comprehension of English Subject-Verb Agreement (SVA)
(Study 1) and the production of English vowels (Study 2). In both HLs, SVA exhibits more contrastive forms than in English. Study 1 demonstrates that this HL characteristic facilitates the comprehension
of English SVA by bilingual preschoolers, more so than the percentage of exposure to English. In contrast, both HLs
exhibit a smaller and phonetically different vowel inventory compared to English. Study 2 demonstrates that the exact vowel inventory of the HL combined with amount of English exposure
helped to explain the acoustic characteristics of the productions of bilingual Spanish-English and Russian-English
preschoolers. These results have clinical and educational relevance.
Acoustic properties of word-final vowels and the acquisition of gender in Spanish-English heritage
speakers
Authors: Colantoni Laura , Pérez Leroux Ana T.
Published: May 2024

This chapter explores whether contact-induced reduction in the inventory of Spanish unstressed
vowels due to contact with English impacts the development of gender morphology and concord in Spanish-English
bilinguals, through the comparison of recent findings from narratives elicited from bilingual adults and children born
in the US. Final unstressed /a, e, o/ were acoustically analyzed and noun phrases were grammatically analyzed. Adult
early bilinguals displayed a large degree of vocalic overlap but were highly accurate in gender. Children showed
variability in their patterns of vocalic overlap and in gender accuracy ranging between 66% to 100%. Results do not
offer a strong support for the hypothesis of a phonetic contribution to heritage gender divergence and call for
refined analyses of the interaction between phonetics and morphosyntax in gender acquisition.
A culture shift to support public involvement and engagement in research
Authors: Eberl Matthias , Cruickshank Sheena M.
Published: May 2024

The need to empower people to understand their health and well-being has never been greater. However, current research culture does not necessarily prioritize public involvement and engagement, and many scientists are left under-equipped to reap its benefits. Here, we outline both the positive need for purposeful public involvement and engagement in biomedical research and major systemic challenges. While some of our examples stem from the UK, we believe the learnings from them have global significance.
Testing an exact diffraction formula with gravitational wave source lensed by a supermassive black hole in binary systems
Authors: Guo Xiao , Cao Zhoujian
Published: May 2024

When it comes to long-wavelength gravitational waves (GWs), diffraction effect becomes
significant when these waves are lensed by celestial bodies. Typically, the traditional
diffraction integral formula neglects large-angle diffraction, which is often adequate for most of
cases. Nonetheless, there are specific scenarios, such as when a GW source is lensed by a
supermassive black hole in a binary system, where the lens and source are in close proximity,
where large-angle diffraction can play a crucial role. In our prior research, we have introduced
an exact, general diffraction integral formula that accounts for large-angle diffraction as
well. This paper explores the disparities between this exact diffraction formula and the
traditional, approximate one under various special conditions. Our findings indicate that, under
specific parameters — such as a lens-source distance of D
LS = 0.1 AU and a lens mass of
 M
L = 4 × 106
M
⊙ — the amplification factor for the exact diffraction formula is
notably smaller than that of the approximate formula, differing by a factor of approximately
 rF
≃ 0.806. This difference is substantial enough to be detectable. Furthermore, our study
reveals that the proportionality factor rF
gradually increases from 0.5 to 1 as D
LS 
increases, and decreases as M
L increases. Significant differences between the exact and
approximate formulas are observable when D
LS ≲ 0.2 AU (assuming M
L 
= 4 × 106
M
⊙) or when M
L ≳ 2 × 106
M
⊙ (assuming D
LS = 0.1 AU). These findings suggest that there is potential to validate our general
diffraction formula through future GW detections.
Fully non-Gaussian Scalar-Induced Gravitational Waves
Authors: Perna Gabriele , Testini Chiara , Ricciardone Angelo , Matarrese Sabino
Published: May 2024

Scalar-Induced Gravitational Waves (SIGWs) represent a particular class of primordial signals which are sourced at second-order in perturbation theory whenever a scalar fluctuation of the metric is present. They form a guaranteed Stochastic Gravitational Wave Background (SGWB) that, depending on the amplification of primordial scalar fluctuations, can be detected by GW detectors. The amplitude and the frequency shape of the scalar-induced SGWB can be influenced by the statistical properties of the scalar density perturbations. In this work we study the intuitive physics behind SIGWs and we analyze the imprints of local non-Gaussianity of the primordial curvature perturbation on the GW spectrum. We consider all the relevant non-Gaussian contributions up to fifth-order in the scalar seeds without any hierarchy, and we derive the related GW energy density ΩGW(f). We perform a Fisher matrix analysis to understand to which accuracy non-Gaussianity can be constrained with the LISA detector, which will be sensitive in the milli-Hertz frequency band. We find that LISA, neglecting the impact of astrophysical foregrounds, will be able to measure the amplitude, the width and the peak of the spectrum with an accuracy up to 𝒪(10-4), while non-Gaussianity can be measured up to 𝒪(10-3). Finally, we discuss the implications of our non-Gaussianity expansion on the fraction of Primordial Black Holes.
Possibility and stabilizing effect of Mo clusters in the Ni-based single-crystal superalloy
Authors: Du Yiqun , Jin Huixin , Kang Rongkai , Zhang Boya , Wang Han , Zhang Jianxin
Published: May 2024

Nickel-based single-crystal superalloys are crucial materials for the preparation of aero-engine turbine blades. Many solute elements are added to superalloys for strengthening. However, the relationship between the clustering behavior of solute atoms and the properties of nickel-based single-crystal superalloys is still unclear. Herein, we conduct first-principles calculations on γ phases with Mo−Mo and Mo−Mo−Ru clusters to reveal the possibility and stabilizing mechanism of solute clusters. Introducing Mo lowers the total energy, binding energy, and formation energy of the γ phase due to the replacement of weak Ni−Ni interaction with strong Mo−Ni bonding. Note that the γ phase containing the Mo−Mo cluster is more stable than that containing a Mo single atom, possibly owing to a wide affecting range. The Ru atom added to the γ phase can further boost system stability, and it tends to form a Mo−Mo−Ru cluster. The stabilizing impact of the Mo−Mo−Ru cluster is demonstrated to be the replacement of weak Ni−Mo interaction by the strong Ru−Mo interaction, which may be derived from the enhanced d-orbital hybridization.
All-electron basis sets for H to Xe specific for ZORA calculations: Applications in atoms and molecules
Authors: Gomes C. S. , Jorge F. E. , Canal Neto A.
Published: May 2024

A segmented basis set of quadruple zeta valence quality plus polarization functions (QZP) for H through Xe was developed to be used in conjunction with the ZORA Hamiltonian. This set was augmented with diffuse functions to describe electrons farther away from the nuclei adequately. Using the ZORA-CCSD(T)/QZP-ZORA theoretical model, atomic ionization energies and bond lengths, harmonic vibrational frequencies, and atomization energies of some molecules were calculated. The addition of core-valence corrections has been shown to improve the agreement between theoretical and experimental results for molecular properties. For atomization energies, a similar observation emerges when considering spin-orbit couplings. With the augmented QZP-ZORA set, static mean dipole polarizabilities of a set of atoms were calculated and compared with previously published recommended and experimental values. Performance evaluations of the ZORA and Douglas–Kroll–Hess Hamiltonians were made for each property studied.
Unit one is intrusive
Authors: Flater David
Published: May 2024

The SI brochure’s treatment of quantities that it regards as dimensionless, with the associated unit one, requires certain physical quantities to be regarded as simply numbers. The resulting formal system erases the nature of these quantities and excludes them from important benefits that quantity calculus provides over numerical value calculations, namely, that accidental confusion of different units and different kinds of quantities is sometimes prevented. I propose a better treatment that entails removing from the SI brochure those prescriptions that conflict with common practices in the treatment of dimensionless quantities, especially the definition and use of non-SI dimensionless units that are distinguished by kind.
Innovative Cesiation Deriving Incredible 145 mA Beam from J-PARC Cesiated RF-Driven H− Ion Source
Authors: Ueno A
Published: May 2024

In NIBS2022, the stable 8 hours operation of the J-PARC cesiated RF-driven H− ion source (IS) in a test-stand with a 69.9 keV 120 mA beam and a beam duty factor of 4 % (1 ms x 40 Hz) was reported. However, the Cesiation condition was produced after many times and rather large amount of Cs and H2Os injections. The fluctuation of the H− ion beam intensity (IH
−) in a pulse and the transverse emittances were rather larger than those for the previous 65 keV 110 mA operation. The plasma electrode temperature (TPE) of 254 °C much higher than that not only for the usual J-PARC IS (about 70 °C) but also for the standard cesiated H− ion sources (180 ∼ 200 °C) suggested the existence of novel H2O mediated cesiation surviving against the high TPE. In this paper, the J-PARC IS improvements based upon a hypothesis of the best cesiation constituted of sub monolayer H2O (chemically bound with Mo) mediated cesiation and Cs half monolayer on remaining surface are presented. The innovative cesiation derived a 76.5 keV 145 mA beam stably with the small beam fluctuation and transverse emittances suitable for Radio Frequency Quadrupole LINACs of high energy LINACs. The measured results of the 145 mA / 83 mA beam, extraction electrode current and RF waveforms, parameter trends of an 8 hours 145 mA operation and the transverse emittances are presented. The optimum TPE was increased from 70 °C to 230 °C. Furthermore, the beam intensity for the J-PARC IS operation energy of 52.5 keV was increased from 72 mA to 83 mA, which was consistent with the 1.5 power perveance law on the beam energy compared with 145 mA for 76.5 keV.
Investigation of plasma chamber erosion in an RF ion source
Authors: George A , Melanson S , Dehnel M , Hoehr C
Published: May 2024

Filament driven plasma sources are widely used to produce ion beams, but they require frequent maintenance due to the limited filament lifetime. External radio-frequency (RF) coupled ion source offers a filament-free plasma and hence better maintenance. However, one of the issues encountered during the development of a planar external RF-powered ion source at D-Pace was the erosion of its copper plasma chamber and subsequent formation of copper deposits on the Aluminum Nitride (AlN) RF window. The copper deposits on the RF window deteriorate the power coupling between the external antenna and the plasma. This paper investigates the erosion of the plasma chamber and describes some of the methods used to control the deposition of copper on the RF window.
Roadmap for the increase of beam brilliance from ECRIS and Microwave Discharge Ion Sources
Authors: Neri Lorenzo , Bilotta G , Boscarino S , Castro G , Celona L , Coco A , Comunian M , Grespan F , Leonardi O , Miraglia A , Russo G , Sorbello G , Gammino S
Published: May 2024

The requirements for future accelerator chains need to increase the injected beam brilliance significantly, still keeping high the beam quality in terms of reliability, reproducibility and stability. A roadmap for ion source development may consist of several steps: plasma simulation, multiphysics simulation of each system component, high-level control system, plasma characterization, beam characterization, data analysis and, again, plasma simulation. The cycle starts and ends with plasma simulation because it is the instrument that shows how different phenomena take part in the plasma and beam formation and because, in such a way, the accuracy grows with each cycle. Commercial multiphysics simulation tools are essential for adequately designing all ion source equipment: magnets, intense electrostatic field regions, microwave propagation and coupling, thermal dissipation and vacuum. The dependence of source performances from source parameters (magnetic field profile, gas pressure, microwave power) has been widely investigated using a high-level control system[1] able to test tens of thousands of source configurations without human interaction. This characterization technique allowed us to identify a new magnetic configuration, High Stability Microwave Discharge Ion Sources[2], that produces a beam with high stability, intensity and brilliance. The plasma simulation tool we developed discloses the role of two types of electrostatic waves in plasma formation and their correlation to stability. The simulation provides a complete view of ions and electrons energy and density distributions, the formation of the plasma meniscus and the beam extraction. The paper will present the results obtained with this development procedure on Microwave Discharge Ion Sources and how we started to apply it to the Electron Cyclotron Resonance Ion Sources development.
Beam divergence of RF negative hydrogen ion sources for fusion
Authors: Wimmer C. , Barnes M. , den Harder N. , Navarro A. , Nocentini R. , Orozco G. , Wünderlich D. , Heinemann B. , Fantz U. , Serianni G. , Veltri P.
Published: May 2024

Neutral beam injectors (NBI) for fusion facilities have strict requirements on the beam divergence (7 mrad for the ITER NBI at 1 MeV). Measurements of the single beamlet divergence of RF negative ion sources (at lower beam energy < 100 keV) show significantly higher values (9–15 mrad), also larger than filament arc sources at similar beam energies. This opened up questions whether the higher divergence is caused by different measurement or evaluation techniques, whether it is a direct cause of the RF source, e.g. due to a higher temperature of negative ions or an oscillating extraction meniscus, and whether it is a problem at all after full acceleration. In a joint effort between the labs modeling and diagnostic capabilities at the NNBI test facilities have been strongly extended and evaluation methods benchmarked. Particularly challenging is the strong increase in beamlet divergence at a lower filling pressure, seen both in filament arc and RF sources.

Beside the source and beam investigations carried out in SPIDER (with selected, isolated apertures rather than the total of 1280 apertures) at Consorzio RFX, the IPP test facilities ELISE (640 apertures) and BATMAN Upgrade (70 apertures) contribute to the physics understanding of the beam optics in RF sources. The determination of the beam divergence is not straight-forward because effects originating from measuring the divergence of multiple beamlets (Beam Emission Spectroscopy) and/or constraints from the individual diagnostic (lateral heat conductance in CFC tiles) lead to difficulties. Still, the divergence requirement is not met at the limited total beam energy available at ELISE and BATMAN Upgrade (< 60kV). However, variation of the beam energy show a decrease of the divergence for higher energies and beam simulation for the ITER NBI accelerator predict that the divergence requirement will be met after full acceleration of the negative ion beam.
Development of air-cooled plasma grid system for long-pulse negative ion beam acceleration with ITER-relevant perveance
Authors: Kisaki M. , Tanaka Y. , Suzuki K. , Hiratsuka J. , Murayama M. , Ichikawa M. , Tobari H. , Kashiwagi M.
Published: May 2024

Long pulse beam experiment has been carried out with a multi-aperture and five-stage accelerator with the same gap length, the same aperture interval, and the same aperture diameter as ITER accelerator in order to demonstrate ITER-relevant beam of 230 Am−2 and 870 keV. An actively cooled plasma grid (PG) with compressed air has been newly developed to maintain the PG temperature within suitable range for surface production of hydrogen negative ion (H–) and to realize the stable H– production. It is confirmed that the air-cooled PG has a capability to control the PG temperature within target range for 300 s with feedback control of the air flow rate. The stable beam acceleration with ITER relevant perveance has been successfully achieved for 300 s at 275 keV with PG cooling, 100 s at 500 keV, and 10 s at 750 keV without PG cooling.
Producing intense uranium ion beam for RIKEN RI beam factory
Authors: Higurashi Y , Saquilayan G Q , Ohnishi J , Haba H , Nagatomo T
Published: May 2024

Intense highly charged uranium (U) ion beams were produced using RIKEN 28 GHz superconducting electron cyclotron resonance (ECR) ion source in a high-temperature oven (HTO). We used a double-oven system to ensure ample vapor supply. Moreover, we optimized the vapor delivery into the plasma at a constant microwave power input. Consequently, we achieved intense U-ion beams, specifically 250 eμA for U35+, 36 eμA for U46+, and 10 eμA for U54+, at an injected microwave power of approximately 3000 W. This achievement stems from recent advancements, notably the optimization of the material consumption rates aimed at maximizing beam intensity, which we briefly review here.
For intense proton beam production with compact ion sources: the ALISES ion source family developed at CEA Saclay
Authors: Tuske O , Delferriere O , Dubois A , Gauthier Y , Harrault F , Sauce Y , Thibeau T
Published: May 2024

The production of intense proton beams in CEA Saclay started in the 90’s with the development of the SILHI source to inject the IPHI accelerator. This ECR ion source is still in operation nowadays. ECR plasma is a well-known heating process and plasma chamber internal dimensions were investigated in order to reduce size and maintenance time. In 2012 R&D investigations on those simple plasma chamber parameters were started with the design of the first ALISES ion source that will give birth to a new source family still in progress today. This paper will summarize the different steps of this development.
First ion source at ISOL@MYRRHA with an improved thermal profile - Theoretical considerations
Authors: Hurier S , Rijpstra K , Ramos J P , Popescu L , Cocolios T E , Mancheva R , Chrysalidis K , Rothe S , Au M , Koliatos A
Published: May 2024

ISOL@MYRRHA will be a new Radioactive Ion Beam (RIB) facility in Belgium based on the Isotope Separation On-Line (ISOL) technique, and established within the framework of MYRRHA, the world’s first large-scale accelerator driven system project at power levels scalable to industrial systems. The surface ion source, or hot cavity, is chosen as initial source for its reliability and simple design. To account for the higher flux of atoms through this cavity, a theoretical study of the processes within the ion source is discussed here, based on theoretical equations and thermal-electric simulations. In the past, the temperature was clearly identified as a key element to this source, but with the assumption that it remains constant throughout the cavity. Nonetheless, more recent thermal-electric simulations have revealed that the source Ohmic heating leads to temperature gradients along the cavity tube. The temperature profile impact on ionisation in the hot cavity will be reviewed here.
New Technique of Injecting Radioactive Ions into Charge Breeding ECR Ion Source
Authors: Tabacaru G , Ärje J , Kolhinen V , Roeder B , Kim G , May D , Clark H
Published: May 2024

Cyclotron Institute at Texas A&M University started a project to develop the reacceleration of radioactive ions using the two operational cyclotrons and a Charge Breeding ECR ion source. The radioactive ions are produced primarily via (p,n) reactions using the IGISOL technique. The reaction products are transported into a Charge Breeder ECR ion source where their charge state is boosted from 1+ to higher charge states. The transport of the radioactive products and the injection into the ion source are very important for the efficiency of charge breeding. Two techniques have been used: acceleration–deceleration method (classic) and low - energy RF-only sextupole ion guide transport and injection method (innovative technique). The last method appears to be very efficient and great charge breeding efficiency was observed. The presentation of the entire project, the new injection technique, experimental results, and future plans will be discussed.
Pulse-stretching out of the CANREB EBIS
Authors: Cavenaile M. , Charles C.R.J. , Kester O. , Schultz B.E. , Ames F. , Kanungo R.
Published: May 2024

The CANadian Rare isotope facility with Electron-Beam ion source (CANREB) at TRIUMF is set to deliver rare isotope beams in high charge states. In the Electron Beam Ion Source (EBIS) ions are charge-bred by collisions with an electron beam of up to 500 mA. A strong magnetic field (up to 6T) maximizes the overlap between ions and electron beam and increases the breeding efficiency. Ion confinement is maintained by a combination of an electrostatic field and the electron beam space-charge potential. Ions are released by lowering the trapping potential with a step function. The system is operated at a pulse repetition frequency up to 100 Hz. Due to the short trap length, this fast extraction scheme produces pulses shorter than 10 µs with high instantaneous rates that can saturate detectors in experiments. Stretching the pulse can be done using a slowly varying voltage function to modify trap electrode potentials instead of a step function. The ideal function produces a pulse with a flat top distribution and can be calculated by knowing the ion energy distribution inside the trap. The latest pulse-stretching results will be discussed including the latest pulse duration up to 1.4 ms that have been produced. The slow extraction scheme has also been used for a measurement of the effective energy distribution of the ions inside the trap.
Production of negative ion beams through charge transfer between negative hydrogen ion beams and non-metallic gases
Authors: Paul A , Melanson S , Junginger T , Dehnel M
Published: May 2024

Negative ion beam applications in tandem accelerators are used for nuclear research, environmental studies, materials analysis, medical treatments, and ion implantation in semiconductor devices. Conventional methods for generating negative ions for tandem accelerators rely on metallic vapors (typically alkali) for charge exchange, which pose challenges like contamination, electrical shorting and breakdowns, and maintenance issues. To address these drawbacks, this work explores an alternative approach to produce negative ions using a non-metallic charge exchange process. It involves directing negative hydrogen ions into neutral gases within a specially designed charge exchange cell equipped with an electrostatic accelerator. The method is applied to various gas targets, including He, H2 and O2, to accelerate and measure resulting negative ions. This innovative approach aims to mitigate contamination concerns associated with metallic vapor double-charge exchange methods and explore novel avenues for negative ion production through charge transfer. Any newly formed negative ion beam current conversion ratios from the incident H− beam will be reported as progress in this research.
A protype of compact and high-yield DD neutron generator
Authors: Chen L H , Cui B Q , Ma R G , Tang B , Ma Y J , Zhang Y F , Ma X , Lee W , Wang Y F
Published: May 2024

Neutron generators are widely utilized in various fields, including scientific research, activation analysis, and detection of IED or drugs, due to their high neutron yield, safety, and flexibility. In this paper, we report about the development of a compact and high-yield dd neutron generator based on an Electron Cyclotron Resonance (ECR) ion source at the China Institute of Atomic Energy. The ion source to produce a high-intensity ion beam, which is used to bombard a water-cooled solid metal target. By means of the (D, D) nuclear reaction, 2.5MeV neutrons are generated. We describe the detailed design of this compact dd neutron generator and present the preliminary measurement results of its neutron yield, as measured by a calibrated 3He neutron detector. The generator has been tested for nearly 300 hours, demonstrating stable operation without any component damage. With its compact size, high yield, and long lifespan, this generator could meet the demand for a 2.5MeV neutron source in many scientific research and select industrial applications.
Numerical study of gas-solid two-phase flow in the snout of continuous hot-dip galvanizing process
Authors: Sun Chuhao , Lin Ying , Cao Jiayong , Tang Chenglong , Wang Xuemin
Published: May 2024

In the hot-dip galvanizing process for strip steel, zinc vapor oxidizes and forms zinc ash in the snout. Given that the snout connects the annealing furnace, the zinc ash will return to the annealing furnace with the gas, affecting the upstream process. The gas-solid two-phase flow regularity in the snout is the key issue for zinc ash control. In this paper, the snout of a hot-dip galvanizing production line was taken as the physical model. The two-phase flow was simulated by the Euler-Lagrange method and the zinc ash particles were simulated via the discrete phase model (DPM). The results show that several vortex regions exist in the snout due to the forced convection caused by the moving strip and changes in flow channel sizes. There exist differences in the movement of zinc ash with different diameters. Small zinc ash has a strong tracking performance with the gas. Large zinc ash is easy to remain in the snout. In addition, orthogonal analysis was conducted to determine the optimal parameter combination. The research results provide theoretical guidance for the operation scheme of the gas circulation system.
Analysis of time sequence and load of pulling rope mechanism of type D-knotter
Authors: Guo Jiayu , Cen Haitang
Published: May 2024

To solve the problem that the rope pulling plate may be delayed in the actual work of the knotter, the influence of the change of the timing of the rope pulling mechanism on the knotter forming performance was studied and analyzed. The dynamic model of the flexible bundling of the knotting machine is established using the Bushing connection of RecurDyn. The timing of the bundling machine homing is controlled by modifying the driving function of the bundling machine, and the positive pressure of the hook pliers is obtained by measuring the contact force between the bundle and the hook pliers. The results of the contact force curve show that the maximum positive pressure of the hook pliers for the normal homing of the rope plate is 290.43 N. The maximum value of the sudden change of tension can reach 837.17 N, which proves that the change in the timing of the rope pulling mechanism has a significant influence on the positive pressure of the hook pliers.
Influence of post-welding heat treatment on microstructure and peculiarity of 10Cr9Mo1VNb boiler steel welded by hot wire TIG
Authors: Li Qin , Lai Chun-Ming , Huang Yan
Published: May 2024

Hot wire tungsten noble gas (HW-TIG) soldering tests are conducted on 10Cr9Mo1VNb boiler steel with multi-layer and multi-pass, and the soldered joints are subjected to post-weld heat treatment (PWHT) at different temperatures and times from 740°C to 790°C and 1 hour to 4 hours. The influence of PWHT on the microstructure and peculiarity of the joints are analyzed by using hardness, metallography, room temperature tensile testing, Charpy impact testing, SEM, and other experimental methods. The results show that the PWHT can transform the martensite formed in the welding process into tempered martensite, which can significantly improve the uniformity of the microstructure and peculiarity of each area of the joint. When subjected to heat treatment at 740°C, both strength and ductility improve with the increase of heat treatment time, while the plasticity gets a slight decrease. However, when subjected to heat treatment at 790°C, strength, plasticity, and ductility decrease with the increase of time, mainly due to the carbide coarsening such as M23C6 in the joint.
Experimental study of penetration for the analysis of pre-cut free surface parameters in rock materials based on response surface methods
Authors: Xu Futong , Lu Jingjing , Zhou Hui , Fang Haibo , He Longpeng
Published: May 2024

The strength of intact rock material is reduced after it has been cut by techniques such as water jets, based on which the use of disc cutter hobs for rock-breaking by hobbing has good economic results. The kerf is the free surface created by water jet cutting. The kerf depth, kerf spacing, and kerf angle are the main parameters affecting the rock-breaking force of the disc cutter, which can be simplified as the normal penetration load of the indenter. To investigate the effect of prefabricated notch parameters on the penetration load and the sensitivity of the response of penetration load to each factor, response surface tests were carried out on sandstone and granite specimens, and every factor’s impact on the penetration load was examined. The results showed that: (1) The single factor analysis and interactive analysis of the prefabricated kerf parameters for sandstone and granite samples showed that the penetration load was negatively correlated with kerf depth and kerf angle, and positively correlated with kerf spacing within the set range of the test. (2) The difference in rock strength can also affect the penetration load of the samples. In the prefabricated kerf-assisted rock-breaking test, for the high-strength rock samples represented by granite, increasing the prefabricated kerf depth can reduce the penetration load of the samples more effectively.
Experimental study on surface roughness processed by ultrasonic surface rolling process
Authors: Wang Haojie , Wang Xiaoqiang
Published: May 2024

In order to explore the formation principle of microscopic morphology of the lower surface of USRP, USRP theoretical analysis and processing experiments are carried out. Firstly, the spatial motion trajectory of tool head by USRP is established to reveal formation principle of surface morphology. Additionally, this experiment employs a single-factor experimental design method. The influence law of process parameters and surface roughness is obtained. The results show that the workpiece speed affects the circumferential machining density of the part, and the feed speed affects the axial density of the part. Surface roughness initially decreases and subsequently increases with rising amplitudes and static pressure. It gradually rises with improvement of feed rate and rotational speed. This provides a new way to adjust the surface topography of USRP in the future.