bluuebunny/crossref_metadata_2025 huggingface dataset:
Position, salience and rhetoric: the strategic tools employed by the main Scottish political parties in the post-devolution era
Authors: Wright Kieran
Published: May 2024

This article presents an original account of the strategic options available to political parties in the form of the position, salience and rhetoric framework. It builds upon existing accounts of party competition by conceiving of rhetorical justification as a distinct tool in the armoury of party strategists alongside the manipulation of policy position and issue salience. It applies that framework to the case of post-devolution Scotland via a quantitative text analysis of the written record of First Ministers Questions sessions in the Scottish Parliament. It shows how the main political parties in Scotland between them utilised all of the strategic tools contained within the PSR framework in the early twenty-first century up to the most recent 2021 election to the Holyrood parliament. It argues that the tactical choices the main Scottish parties made within this framework can help explain the differing electoral fortunes experienced by those parties in the post-devolution era.
Decent work and innovative work behavior of academic staff in higher education institutions: the mediating role of work engagement and job self-efficacy
Authors: Hassan Rasha S. , Amin Hala M. G. , Ghoneim Hebatallah
Published: May 2024

Decent work was proposed by International Labour Organization (ILO) as an institutional measure to address challenges faced by labor in the current competitive dynamic labor market. This study aims to investigate the impact of “decent work” dimensions on faculty members’ Innovative Work Behaviour (IWB) in higher education institutes. The study also explores the possible role of work engagement in mediating this relationship. Moreover, the study aims to discover the role of job self-efficacy in mediating the relationship between decent work and work engagement. Using the SEM (Structural Equational Modelling) method, we test our model’s hypotheses with data from 224 faculty members working in higher education institutes through the use of questionnaires. Results suggest that “decent work” was a predictor of IWB only through the full mediation of work engagement. Decent work was found to significantly impact job self-efficacy and work engagement. Furthermore, job self-efficacy was found to play an important role in promoting work engagement and acts as a mediating variable in the relationship between decent work and work engagement. Findings encourage education policymakers to implement new strategies and policies to promote higher levels of decent work for faculty members, with greater emphasis on work engagement, to enhance their IWB. This study is one of a few studies conducted in emerging economies that highlight “decent work” as an essential job resource, useful in enhancing work engagement and leading to higher IWB among faculty members in higher education institutions.
Hesitant or determined? The influence of social and environmental factors on settlement decision-making of rural in-migrants: evidence from Dali, China
Authors: Li Yali , Yan Ni , Cheng Haifan , Luo Jing , Zhou Zhengxu
Published: May 2024

The phenomenon of rural in-migration is emerging as a significant trend in various global hotspots, playing a crucial role in reshaping these rural areas from social and spatial perspectives. The decision-making process for rural in-migrants regarding settlement is complex. Although previous studies have acknowledged that settlement intentions are influenced by social and environmental factors, such as the economy, natural environment, and public service facilities, many have relied on a stated-preference approach to measure migrants’ settlement intentions. This method may overlook the inherent complexity and fluidity of the decision-making process. Drawing upon the Theory of Planned Behavior (TPB), this paper formulates questions aligned with the three stages of decision-making to examine the settlement intentions of rural in-migrants. Employing multiple linear regression analysis, the study assesses the impact of social and environmental factors on the settlement decisions of rural in-migrants in four villages surrounding Dali, a renowned rural destination in southwest China that attracts a diverse range of migrants. The findings highlight the pivotal role of public service facilities’ quality in rural villages in the decision-making process, particularly among those who have already formulated settlement plans. Additionally, the research reveals that female in-migrants place a heightened emphasis on the quality of these facilities. Furthermore, a higher level of education correlates with a broader diversity of influencing factors. As migrants age, a wider range of considerations comes into play, with the natural environment emerging as a key factor for older in-migrants. This article emphasizes the equal importance of continuously improving public service facilities, strengthening economic vitality, and protecting rural natural landscapes to support the development of rural communities.
The role of comfort, personality, and intention in smartwatch usage during sleep
Authors: Li Hongting , Xu Bingfei , Sun Zaoyi , Yan Rui , Wu Yingchao , Zhang Haimo , Zhou Keyuan , Xu Liang
Published: May 2024

The comfort of a smartwatch is recognized as a pivotal determinant affecting users’ engagement with the device. This study delved into the intricate interplay between smartwatch comfort, users’ behavioral intention, and their actual usage behavior within the specific context of sleep. Through the lens of a structural equation model, we find that the appearance and movement dimensions of comfort significantly influence users’ intention to wear the smartwatch during sleep, while other dimensions like pressure, harm, attachment, and perceived change do not show significant effects. Furthermore, this intention significantly translated into smartwatch usage behavior. Building on these insights, we subsequently embarked on an exploration of how personality traits interplay with comfort and intention to impact smartwatch usage during sleep. The moderated mediation models revealed that the personality trait of openness acts as a moderator, amplifying the relationship between smartwatch comfort and behavioral intention. Individuals with higher levels of openness exhibit increased inclination to adopt the smartwatch during sleep, even when comfort is compromised. These insights contribute to a nuanced understanding of smartwatch usage behavior and offer guidance for personalized design strategies, especially within the sleep context.
The spatial effect of low-carbon development of regional industries driven by the digital economy: evidence from Chinese cities
Authors: Zhang Tian , Zhang Rong
Published: May 2024

Utilizing data that encompass municipalities and regions within China at the prefectural level and beyond, spanning the period from 2012 to 2021, this study employed the spatial Durbin model to assess the spatial spillover impact of the digital economy in propelling low-carbon advancement within regional physical industries. This investigation elucidates the spatial spillover mechanism that underlies the low-carbon evolution of regional industries catalyzed by the digital economy and offers nuanced insights. The findings delineate the following observations: (1) The digital economy propels the low-carbon progression of indigenous physical industries and stimulates the low-carbon development of proximate regions’ physical industries through discernible spatial spillover effects. (2) The spatial spillover ramifications of the digital economy manifest a substantive correlation with urban attributes, including geographical positioning, population size, and market integration levels. Notably, municipalities situated in the southeast coastal region, those characterized by larger population sizes, and those exhibiting heightened market integration levels show greater spatial spillover effects attributable to the digital economy. (3) The safeguarding of intangible asset equity property, a pivotal institutional underpinning for fostering digital economic development, amplifies the spatial spillover effect of the digital economy in propelling low-carbon development within regional industries. (4) As geographical and spatial distances expand, the spatial spillover effect of the digital economy attenuates, indicating a diminishing influence with increasing spatial separation.
Large anisotropic room-temperature ferromagnetism in yttrium-doped HfO2 thin film
Authors: Xie Liang , Qin Yucheng , Min Yueqi , Jiang Haolan , Xie Wenqin , Yu Jianqiang , An Yanwei , Tie Xiaoyun , Zhang Jing , Fu Chen , Liu Fengguang , Zhang Hongguang , Huang Haoliang
Published: May 2024

The realization of room-temperature ferromagnetism in ferroelectric thin films based on HfO2 is a crucial step in broadening the applicability of HfO2-based materials and advancing their utility in spintronics devices. Nevertheless, the substitution of magnetic ions may lead to a reduction in resistivity, posing a challenge to the maintenance of ferroelectricity. Additionally, the resulting dilute magnetic semiconductors often exhibit relatively insignificant magnetic properties. In this study, we achieved substantial room-temperature ferromagnetism and anisotropic magnetism in epitaxial thin films of yttrium-doped HfO2 (HYO) on (111)-oriented yttrium-stabilized zirconia substrates. Remarkably, room-temperature ferromagnetism was observed in the as-grown HYO thin films, and its magnitude was significantly amplified through an annealing process. Simultaneously, the anisotropic magnetization behavior in the HYO film could be modulated by adjusting the film thickness and employing different temperature annealing procedures. The variations in anisotropic magnetization and ferromagnetism were attributed to changes in the concentration of oxygen vacancies, which were influenced by both film thickness and annealing conditions. These findings suggest that the manipulation of thickness and defects can effectively control the anisotropic ferromagnetic properties of epitaxial HYO thin films, thereby holding promise for the integration of metal-oxide semiconductors with spintronics.
Turing instability analysis and parameter identification based on optimal control and statistics method for a rumor propagation system
Authors: Li Bingxin , Zhu Linhe
Published: May 2024

This study establishes a reaction–diffusion system to capture the dynamics of rumor propagation, considering two possibilities of contact transmission. The sufficient and necessary conditions for a positive equilibrium point are provided, and the Turing instability conditions for this equilibrium point are derived. Furthermore, utilizing variational inequalities, a first-order necessary condition for parameter identification based on optimal control is established. During the numerical simulation process, the correctness of the Turing instability conditions is verified, and optimal control-based parameter identification is applied to the target pattern. Additionally, statistical methods are employed for pattern parameter identification. The identification results demonstrate that optimal control-based parameter identification exhibits higher efficiency and accuracy. Finally, both theories’ parameter identification principles are extended to a small-world network, yielding consistent conclusions with continuous space.
Environmental predictors of forest structure, tree growth and wood production for Xylocarpus granatum in mixed-species mangrove forests
Authors: Robertson Alistar I. , Zagorskis Irena , Logan Murray , Dixon Paul , Daniel Paul
Published: May 2024

Context Restored mangrove forests are threatened by the restricted range of species used. Xylocarpus granatum has excellent timber and could add value in mangrove plantings. Methods Forest structure and environmental variables were measured at 40 sites in northern Australia and Papua New Guinea. Tree growth was measured at 18 sites. Boosted regression tree modelling identified environmental predictor variables for above-ground biomass for X. granatum (AGBX), mean annual increment in diameter at breast height (DBH) for X. granatum (MAIX) and wood production (PW). Aims To determine the environmental conditions under which X. granatum has the greatest biomass and growth. Key results Increasing stem density, basal area and AGB of other tree species were most important in limiting AGBX. MAIX (range 0.03–0.55 cm year−1) was greatest when sediment redox potential was >100 mV and mean annual catchment rainfall was >4000 mm. MAIX increased with an increasing mean minimum air temperature and sediment percentage silt and percentage phosphorus. PW declined with the stem density of all species and increased with an increasing percentage silt and when sediment redox potential was >180 mV. Conclusions and implications Under optimal conditions, X. granatum grows as fast as most mangrove species and could make an excellent, harvestable addition to the species mix used in restoration projects.
Infants who are rarely spoken to nevertheless understand many words
Authors: Foushee Ruthe , Srinivasan Mahesh
Published: May 2024

Theories of language development—informed largely by studies of Western, middleclass infants—have highlighted the language that caregivers direct to children as a key driver of language learning. However, some have argued that language development unfolds similarly across environmental contexts, including those in which childdirected language is scarce. This raises the possibility that children are able to learn from other sources of language in their environments, particularly the language directed to others in their environment. We explore this hypothesis with infants in an indigenous Tseltal-speaking community in Southern Mexico who are rarely spoken to, yet have the opportunity to overhear a great deal of other-directed language by virtue of being carried on their mothers’ backs. Adapting a previously established gaze-tracking method for detecting early word knowledge to our field setting, we find that Tseltal infants exhibit implicit knowledge of common nouns (Exp. 1), analogous to their US peers who are frequently spoken to. Moreover, they exhibit comprehension of Tseltal honorific terms that are exclusively used to greet adults in the community (Exp. 2), representing language that could only have been learned through overhearing. In so doing, Tseltal infants demonstrate an ability to discriminate words with similar meanings and perceptually similar referents at an earlier age than has been shown among Western children. Together, these results suggest that for some infants, learning from overhearing may be an important path toward developing language.
Escherichia coliself-organizes developmental rosettes
Authors: Puri Devina , Allison Kyle R.
Published: May 2024

Rosettes are self-organizing, circular multicellular communities that initiate developmental processes, like organogenesis and embryogenesis, in complex organisms. Their formation results from the active repositioning of adhered sister cells and is thought to distinguish multicellular organisms from unicellular ones. Though common in eukaryotes, this multicellular behavior has not been reported in bacteria. In this study, we found thatEscherichia coliforms rosettes by active sister-cell repositioning. After division, sister cells “fold” to actively align at the 2- and 4-cell stages of clonal division, thereby producing rosettes with characteristic quatrefoil configuration. Analysis revealed that folding follows an angular random walk, composed of ~1 µm strokes and directional randomization. We further showed that this motion was produced by the flagellum, the extracellular tail whose rotation generates swimming motility. Rosette formation was found to require de novo flagella synthesis suggesting it must balance the opposing forces ofAg43adhesion and flagellar propulsion. We went on to show that proper rosette formation was required for subsequent morphogenesis of multicellular chains,rpoSgene expression, and formation of hydrostatic clonal-chain biofilms. Moreover, we found self-folding rosette-like communities in the standard motility assay, indicating that this behavior may be a general response to hydrostatic environments inE. coli. These findings establish self-organization of clonal rosettes by a prokaryote and have implications for evolutionary biology, synthetic biology, and medical microbiology.
Niclosamide potentiates TMEM16A and induces vasoconstriction
Authors: Liang Pengfei , Wan Yui Chun S. , Yu Kuai , Hartzell H. Criss , Yang Huanghe
Published: May 2024

The TMEM16A calcium-activated chloride channel is a promising therapeutic target for various diseases. Niclosamide, an anthelmintic medication, has been considered a TMEM16A inhibitor for treating asthma and chronic obstructive pulmonary disease (COPD) but was recently found to possess broad-spectrum off-target effects. Here, we show that, under physiological Ca2+ (200–500 nM) and voltages, niclosamide acutely potentiates TMEM16A. Our computational and functional characterizations pinpoint a putative niclosamide binding site on the extracellular side of TMEM16A. Mutations in this site attenuate the potentiation. Moreover, niclosamide potentiates endogenous TMEM16A in vascular smooth muscle cells, triggers intracellular calcium increase, and constricts the murine mesenteric artery. Our findings advise caution when considering clinical applications of niclosamide as a TMEM16A inhibitor. The identification of the putative niclosamide binding site provides insights into the mechanism of TMEM16A pharmacological modulation and provides insights into developing specific TMEM16A modulators to treat human diseases.
Playing lato–lato is difficult and this is why
Authors: Funata Fansen Candra , Abidin Zainul
Published: May 2024

Lato–lato, a pendulum-based toy gaining popularity in Indonesian playgrounds, has sparked interest with competitions centered around maintaining its oscillatory motion. While some find it easy to play, the challenge lies in sustaining the oscillation, particularly in maintaining both ‘up and down collisions.’ Through a Newtonian dynamics numerical analysis using Python (code by ChatGPT), this study identifies two equilibrium phases—phase 1, characterized by normal pendulum motion, and phase 2, the double collision mode—using the driven oscillation model. In addition, further analysis and discussion are done using the obtained numeric data. The difficulty in remaining in phase 2 highlights the intricate hand-eye coordination required, shedding light on the toy’s appeal and the skill it demands.
Method for determining the Schottky injection barrier at the interface of a metal electrode with insulating oil or pressboard
Authors: Chen Congcong , Gao Chunjia , Qi Bo , Li Chengrong
Published: May 2024

The Schottky injection barrier plays a crucial role in determining the charge movement and migration process, yet its electric field and temperature properties remain unclear. The precise determination of the Schottky injection barrier value is essential for understanding the charge migration dynamics at the interface between the metal electrode and the oil-pressboard insulating medium. This study introduces a computational approach to determine the Schottky injection barrier, derived from classical Schottky emission theory. The methodology employed in this research aligns with previous studies, utilizing the Schottky emission current mechanism to describe steady-state conduction current. Results indicate that the Schottky injection barrier increases with temperature, with a 17.09% rise for oil-electrode and an 8.3% increase for pressboard-electrode in the temperature range of 299 K–353 K. These temperature-dependent variations are attributed to the negative temperature dependence of the Fermi energy levels of the metal electrodes. Furthermore, the impact of electric field strength on the Schottky injection barrier is found to be minimal. By developing a bipolar charge transport simulation model and validating the injection barrier for 0.5 mm oil-immersed pressboard, this study confirms the accuracy of the calculated Schottky injection barrier. The insights provided in this research could aid in simulating charge transport and analyzing charge characteristics in oil-paper/pressboard insulation systems.
Simultaneous electric dipoles and flat-band voltage modulation in 4H-SiC MOS capacitors through HfO2/SiO2 interface engineering
Authors: Wang Xinwei , Wei Shubo , Ke Huihuang , Ye Xiaofeng , Weng Hongjin , Wong Shen Yuong , Yang Weifeng
Published: May 2024

We report an approach to simultaneously tune the electric dipoles and flat-band voltage (V
FB) of 4H-silicon carbide (SiC) metal-oxide-semiconductor (MOS) capacitors through high-k oxide dielectric interface engineering. With an additional HfO2 thin layer on atomic layer deposition (ALD) of SiO2 film, a dipole layer was formed at the HfO2/SiO2 interface, leading to a small positive shift of the V
FB of 0.3 V in 4H-SiC MOS capacitors. The Kelvin probe method was used to examine the dipole layers induced at the direct-contact oxide/4H-SiC interfaces. It was found that a minor difference of 0.3 V in the contact potential difference (V
CPD) is observed between the SiO2/4H-SiC and HfO2/SiO2/4H-SiC stacks, which signifies the presence of a weak interface dipole layer at the interface of HfO2 and SiO2. Additionally, investigation of the interface state density reveals that ALD of the HfO2 process had a negligible impact on the quality of the SiO2/4H-SiC interface, suggesting that the observed small positive V
FB shift originated from the HfO2/SiO2 interface rather than the SiO2/4H-SiC interface.
Hybrid magneto-plasmonic structure consisting of hexagonal periodic nanodisks array with giant transverse magneto-optical Kerr effect for sensing application
Authors: Wang Ziqi , Cui Xiaojian , Zhu Ruixue , Li Jianhua , Zhang Bo , Song Yujun
Published: May 2024

The present study proposes a theoretical design of the magneto-optical surface plasmon resonance (MOSPR) refractive index sensor that utilizes a magnetic field for modulating the dispersion of surface plasmon. This sensor based on the transverse magneto-optical Kerr effect (TMOKE) is constructed using a hybrid magneto-plasmonic film covered with an array of hexagonal periodic Au nanodisks. The structural parameters were optimized to obtain the Fano shape TMOKE response characterized by an extremely narrow bandwidth (0.00997°) and remarkably high amplitude (0.99). The excitation of the optimal surface plasmon resonance (SPR) and the resonance enhancement effect of multi-mode coupling enables us to achieve a surface sensitivity of 207.5 deg RIU−1 and a high figure of merit of the order of 104 RIU−1, surpassing conventional SPR and MOSPR sensors by at least one order of magnitude. The present study offers a comprehensive guideline for the design of high-performance magneto-plasmonic sensors, facilitating instrument miniaturization and manufacturing cost reduction.
Electronic structures of metal/H-diamond (111) interfaces by ab-initio studies
Authors: Xu Erqi , Xie Zhiyang , Cheng Chunmin , He Xiaofei , Shen Wei , Wu Gai , Liang Kang , Guo Yuzheng , Ju Guangxu , Cao Ruyue , Zhang Zhaofu
Published: May 2024

With ultra-wide bandgap and outstanding thermal properties, diamond-based high-power devices have excellent application prospects. The crystal structure and electronic property of the metal/hydrogen-terminated diamond (H-diamond) interfaces have been extensively studied experimentally, but the Schottky barrier height (SBH) theory at the metal/H-diamond interface has not been systematically investigated yet. In this work, SBHs of interfaces formed by H-diamond (111) surfaces with 12 metals (Y, Sc, Mg, Ag, Al, Ti, Cu, Co, Pd, Ni, Au and Pt) are investigated using ab-initio calculations. The fitted curve of the SBH with respect to the metal work function is obtained with a Fermi pinning factor of 0.30, which is close to the empirical value of 0.36. Due to the negative electron affinity of H-diamond, Schottky contacts can be formed with low work function metals, which is useful in device design to regulate the SBH and it is relatively easier to form ohmic contacts with high work function metals, leading to low contact resistances. Our work sheds light on the rational design of diamond-based semiconductor devices with low contact resistances.
Disorder induced band gap lowering in kesterite type Cu2ZnSnSe4 and Ag2ZnSnSe4: a first-principles and special quasirandom structures investigation
Authors: Fritsch Daniel , Schorr Susan
Published: May 2024

Quaternary chalcogenides, i.e. Cu2ZnSnS4, crystallising in the kesterite crystal structure have already been demonstrated as potential building blocks of thin film solar cells, containing only abundant elements and exhibiting power conversion efficiencies of about 14.9% so far. However, due to the potential presence of several structurally similar polymorphs, the unequivocal identification of their ground state crystal structures required the application of more elaborate neutron diffraction experiments. One particular complication arose from the later identified Cu–Zn disorder, present in virtually all thin film samples. Subsequently, it has been shown experimentally that this unavoidable Cu–Zn disorder leads to a band gap lowering in the respective samples. Additional theoretical investigations, mostly based on Monte-Carlo methods, tried to understand the atomistic origin of this disorder induced band gap lowering. Here, we present theoretical results from first-principles calculations based on density functional theory for the disorder induced band gap lowering in kesterite Cu2ZnSnSe4 and Ag2ZnSnSe4, where the Cu–Zn and Ag–Zn disorder is modelled via a supercell approach and special quasirandom structures. Results of subsequent analyses of structural, electronic, and optical properties are discussed with respect to available experimental results, and will provide additional insight and knowledge towards the atomistic origin of the observed disorder induced band gap lowering in kesterite type materials.
HTR+: a novel algorithm for identifying type and polycrystal of gas hydrates
Authors: Shi Qiao , Lin Ziyan , Qu Yongxiao , Wu Jianyang , Zhang Zhisen
Published: May 2024

In this work, the hierarchical topology ring (HTR+) algorithm, an extension of the HTR algorithm, was developed for identifying gas hydrate types, cage structures, and grain boundaries (GBs) within polycrystalline structures. Utilizing molecular dynamics trajectories of polycrystalline hydrates, the accuracy of the HTR+ algorithm is validated in identifying sI, sII and sH hydrate types, hydrate grains, and GBs in multi-hydrate polycrystals, as well as clathrate cages at GBs. Additionally, during the hydrate nucleation and growth processes, clathrate cages, hydrate type, hydrate grains and ice structures are accurately recognized. Significantly, this algorithm demonstrates high efficiency, particularly for large hydrate systems. HTR+ algorithm emerges a powerful tool for identifying micro/mesoscopic structures of gas hydrates, enabling an in-depth understanding of the formation mechanisms and properties of gas hydrates.
Crystal structure, properties and pressure-induced insulator-metal transition in layered kagome chalcogenides
Authors: Du Hong , Zheng Yu , Pei Cuiying , Yim Chi-Ming , Qi Yanpeng , Zhong Ruidan
Published: May 2024

Layered materials with kagome lattice have attracted a lot of attention due to the presence of nontrivial topological bands and correlated electronic states with tunability. In this work, we investigate a unique van der Waals (vdW) material system, A
2
M
3
X
4 (A = K, Rb, Cs; M = Ni, Pd; X = S, Se), where transition metal kagome lattices, chalcogen honeycomb lattices and alkali metal triangular lattices coexist simultaneously. A notable feature of this material is that each Ni/Pd atom is positioned in the center of four chalcogen atoms, forming a local square-planar environment. This crystal field environment results in a low spin state S= 0 of Ni2+/Pd2+. A systematic study of the crystal growth, crystal structure, magnetic and transport properties of two representative compounds, Rb2Ni3S4 and Cs2Ni3Se4, has been carried out on powder and single crystal samples. Both compounds exhibit nonmagnetic p-type semiconducting behavior, closely related to the particular chemical environment of Ni2+ ions and the alkali metal intercalated vdW structure. Additionally, Cs2Ni3Se4 undergoes an insulator-metal transition (IMT) in transport measurements under pressure up to 87.1 GPa without any structural phase transition, while Rb2Ni3S4 shows the tendency to be metalized.
Remaining useful life prediction method of rolling bearings based on improved 3σ and DBO-HKELM
Authors: Gao Shuzhi , Li Zeqin , Zhang Yimin , Zhang Sixuan , Zhou Jin
Published: May 2024

An improved 3σ method and dung beetle algorithm optimization hybrid kernel extreme learning machine-based (DBO-HKELM) approach for predicting the remaining useful life (RUL) of rolling bearings was suggested in order to increase prediction accuracy. Firstly, multi-dimensional degradation feature data is extracted from bearing vibration data. Considering the influence of noise signal on the prediction accuracy, an improved kernel principal component analysis method is proposed to reduce the noise of degraded features. Then, an improved 3σ method is proposed to determine the starting point of bearing degradation by combining bearing vibration signal data. Lastly, a DBO-HKELM life prediction model was put forth. The parameters of hybrid kernel extreme learning machine were optimized by dung beetle algorithm, and appropriate kernel parameters and regularization coefficient were selected. The feature set of degradation indicators is input into the trained model to output the bearing RUL prediction results starting from the determined degradation starting point. Multiple data sets were used to verify that the new RUL prediction method significantly improves the prediction accuracy.
Design of SEE-Tolerant analog switch chip with a novel diode structure
*
Authors: Huang Wei , Liu HongXia , Xu Qing
Published: May 2024

This paper proposes a novel circuit-level design in order to enhance the radiation tolerance of an analog switch integrated circuit. After analyzing the mechanisms of single-particle sensitivity in a high-voltage analog switch chip fabricated using a commercial 1 μm complementary metal–oxide–semiconductor process, a diode unit was employed to reduce the V
GS (voltage between the gate and the base) of the parasitic triode within the metal–oxide–semiconductor field-effect transistor of the switch. This reduction lowered the probability of activating the parasitic triode in response to single-event effect (SEE). Subsequently, single-particle irradiation experiments proceeded with the high-voltage analog switch chip, both with and without the diode unit. In the unreinforced device, the current of the power supply reached 100 mA within 11 s of single-particle irradiation at 75.8 MeV•cm2 mg−1. In contrast, in the reinforced device, the current of the power supply remained relatively stable under irradiation at both 37.2 and 75.8 MeV•cm2 mg−1. These findings indicate that the reinforced analog switch chip exhibits an SEE tolerance exceeding 75.8 MeV•cm2 mg−1, highlighting its potential to enhance the radiation tolerance of analog switches.
Optical crosstalk of protective cover on MPPC array for TOF PET detector
Authors: Yoshida Eiji , Obata Fujino , Yamaya Taiga
Published: May 2024

Objective. Time-of-flight (TOF) is an important factor that directly affects the image quality of PET systems, and various attempts have been made to improve the coincidence resolving time (CRT) of PET detectors. For independent readout detectors, the timing is acquired for each silicon photomultiplier (SiPM), so they are less sensitive to diffused scintillation light, resulting in a better CRT. Further improvement can be expected if the light can be focused on a single SiPM. However, existing SiPM arrays have a thin protective cover on the SiPM and the gap between the SiPMs is filled with either air or the protective cover, so the light must diffuse through the cover. In this work, we investigated optical crosstalk in the protective cover to improve the CRT. Approach. We used 3.1 × 3.1 × 20 mm3 fast LGSO crystals and 3 mm square 8 × 8 multi pixel photon counter (MPPC) arrays. Pitch of the MPPCs was 3.2 mm and thickness of the protective cover on them was 150 μm. To reduce diffusion of scintillation light in the protective cover, the part of the inactive areas on the MPPC array were optically separated using reflective material. Specifically, 50, 100, 150, and 350 μm deep grid-shaped slits were made along the inactive area of the MPPCs and they were filled with BaSO4 powder as the reflective material. Main results. Coincidence counts were measured with a pair of TOF detectors, and the CRT was shorter with a deeper slit depth. The CRT before improvement was 235 ps, and using the cover having the 350 μm deep slits filled with reflective material lowered the CRT to 211 ps. Significance. Up to 10% of the scintillation light was diffused to other MPPCs by the protective cover, and the CRT was degraded by 10% due to optical crosstalk of the cover. The proposed method promises to improve the CRT of the TOF detector.
Deformable anthropomorphic pelvis phantom for dose accumulation verification
Authors: Wong Yun Ming , Koh Calvin Wei Yang , Lew Kah Seng , Chua Clifford Ghee Ann , Yeap Ping Lin , Zhang Ee Teng , Ong Ashley Li Kuan , Tuan Jeffrey Kit Loong , Ng Bing Feng , Lew Wen Siang , Lee James Cheow Lei , Tan Hong Qi
Published: May 2024

Objective. The validation of deformable image registration (DIR) for contour propagation is often done using contour-based metrics. Meanwhile, dose accumulation requires evaluation of voxel mapping accuracy, which might not be accurately represented by contour-based metrics. By fabricating a deformable anthropomorphic pelvis phantom, we aim to (1) quantify the voxel mapping accuracy for various deformation scenarios, in high- and low-contrast regions, and (2) identify any correlation between dice similarity coefficient (DSC), a commonly used contour-based metric, and the voxel mapping accuracy for each organ. Approach. Four organs, i.e. pelvic bone, prostate, bladder and rectum (PBR), were 3D printed using PLA and a Polyjet digital material, and assembled. The latter three were implanted with glass bead and CT markers within or on their surfaces. Four deformation scenarios were simulated by varying the bladder and rectum volumes. For each scenario, nine DIRs with different parameters were performed on RayStation v10B. The voxel mapping accuracy was quantified by finding the discrepancy between true and mapped marker positions, termed the target registration error (TRE). Pearson correlation test was done between the DSC and mean TRE for each organ. Main results. For the first time, we fabricated a deformable phantom purely from 3D printing, which successfully reproduced realistic anatomical deformations. Overall, the voxel mapping accuracy dropped with increasing deformation magnitude, but improved when more organs were used to guide the DIR or limit the registration region. DSC was found to be a good indicator of voxel mapping accuracy for prostate and rectum, but a comparatively poorer one for bladder. DSC > 0.85/0.90 was established as the threshold of mean TRE ⩽ 0.3 cm for rectum/prostate. For bladder, extra metrics in addition to DSC should be considered. Significance. This work presented a 3D printed phantom, which enabled quantification of voxel mapping accuracy and evaluation of correlation between DSC and voxel mapping accuracy.
Study of impurity C transport and plasma rotation in negative triangularity on the TCV tokamak
Authors: Bagnato F , Duval B P , Sauter O , Coda S , Karpushov A , Merle A , Labit B , Fevrier O , Pau A , Mykytchuk D , Porte L , Ball J
Published: May 2024

Carbon impurity transport is studied in the TCV tokamak using a charge exchange recombination diagnostic. TCVs flexible shaping capabilities were exploited to extend previous impurity transport studies to negative triangularity (δ < 0). A practical way of studying light impurity transport (like C, TCVs main impurity species due to graphite tiled walls) is to investigate the correlations between the impurity ion gradients that, in this study, highlighted significant differences between positive (PT) and negative δ (NT) plasma configurations. δ scans (

−
0.6
<
δ
<
+
0.6

) were performed in limited configurations, but displayed little correlation between C temperature, rotation and density gradients for positive δ. This stiff response for δ > 0 changes for negative δ, where the evolution of

∇

v

tor

was accompanied by variations of

∇

n

C

over a range of negative δ, showing that transport, in NT, is affected by velocity gradients. Similar δ scans were performed with additional NBH (Neutral Beam Heating), with power steps ranging from 0.25 MW to 1.25 MW, highlighting increased momentum confinement in negative δ. Finally, the evolution of intrinsic plasma toroidal rotation across linear to saturated ohmic confinement regime (LOC/SOC) transitions was explored at δ < 0, expanding previous studies performed in TCV for

δ
>

0 (Bagnato et al 2023 Nucl. Fusion
63 056006). Toroidal rotation reversal was not observed for δ < 0, despite clear LOC/SOC transitions, confirming that these two phenomena occur concomitantly only in a restricted number of cases and under specific conditions.
Trends in mass utilization of a magnetically shielded Hall thruster operating on xenon and krypton
Authors: Su Leanne L , Marks Thomas A , Jorns Benjamin A
Published: May 2024

The trends in mass utilization with increasing discharge voltage and current are investigated for a magnetically shielded Hall thruster operating on xenon and krypton. A 9 kW class shielded thruster is operated with discharge voltages from 300 to 600 V and discharge currents from 15 to 30 A on xenon and krypton. Experimental measurements of discharge current, thrust, anode efficiency, and ion velocity as a function of axial position are used to calibrate a multi-fluid 2D Hall thruster code at all operating conditions. The results of these calibrated simulations are employed to interrogate the plasma properties inside the thruster channel. A simplified 0D model for mass utilization evaluated on spatial averages of the simulated plasma parameters is employed to interpret the response of this efficiency mode with power for each propellant. It is found that with both higher voltage and current, mass utilization increases for both gases and their relative gap in this efficiency decreases. This can be attributed to the higher plasma densities and ionization rate coefficients at high voltage, and solely to higher plasma densities at high current. The driving factors for the increase in mass utilization are examined in the context of its nonlinear response to internal plasma properties. The behavior of mass utilization is also discussed in context of the gap in overall efficiency between the propellants. Finally, the implications of these results for improving the performance of high power Hall thrusters operating on krypton are examined.
Electron trapping efficiency of a magnetron sputtering cathode
Authors: Salahshoor Mostafa
Published: May 2024

A common feature of all types of magnetron sputtering (MS) assemblies is an effective confinement of electrons by an appropriate combination of electric and magnetic fields. Therefore, studying the motions of electrons in the fields of magnetron assemblies is of particular importance. Here, we systematically analyze the electrons motions in front of a typical DC MS cathode. We first calculate the profiles of the magnetron’s magnetic field for balanced and two types of unbalanced configurations. Then, we compute the profiles of the cathode’s electric field before the gas discharge and after the plasma formation. A semi-analytical model is utilized to compute the plasma potential. We then track the motions of electrons released from the target and electrons produced through impact ionization of the background gas in the prescribed fields. A Monte Carlo model is implemented to consider electron-gas collisions and a mixed boundary condition is employed to account for electron-wall interactions. The study analyzes the impact of field profiles on the cathode’s efficiency in trapping electron by examining electron escape from the magnetic trap and electron recapture at the target surface. It is shown that the presence of plasma in all configurations leads to a significant increase in the trapping efficiency and the ionization performance, as well as a decrease in the recapture probability. These effects are attributed to the high electric field developed in the cathode sheath. Moreover, we statistically analyze the trapping efficiency by illustrating the spatial distributions of electrons locations in both axial and radial dimensions. It is demonstrated that during their azimuthal drift motion, the electrons released from the middle region at the target surface have the smallest range of axial and radial locations, in all configurations in the absence of plasma. Finally, the impact of field profiles on the average energies of electrons is discussed.
Incorporation of zinc oxide and cobalt doped zinc oxide nano-rods in commercial sunscreen sample to optimize its UV-ray absorption
Authors: Ansari Komal , Riaz Rehana , Gull Fatima , Atiq Haleema
Published: May 2024

In the last two decades, the ozone layer in the atmosphere has been depleted, and the sun rays are now more harmful to human skin because they no longer filters it completely. Long-term exposure to harmful ultraviolet rays (UV-rays), which have wavelengths between 220 nm and 380 nm, causes catastrophic damage to skin cells. Sunscreens are therefore absolutely necessary to protect the skin. The co-precipitation method was used to synthesize both pure and cobalt-doped zinc oxide nano structures. In sunscreens, these nanostructures serve as a UV filter. The obtained nano structures have been characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), and diffuse reflectance spectroscopy (DRS). The ability of a sunscreen sample containing nano structures to yield results for a period of various hours at different temperatures (20 °C, 30 °C, and 50 °C) has been tested. According to XRD results, prepared samples exhibits hexagonal wurtzite crystalline structures and are of 22 nm in size for pure zinc oxide and 20 nm in size for cobalt- doped zinc oxide. SEM was used to find morphologies, i.e., nano rods (NRs) at 200 nm and 2 μm. DRS provided evidence of sunscreen’s endurance, with a 97% absorption of UV-rays at 50 °C for up to 6 h when incorporated with NRs. In order to boost UV-ray absorption in sunscreen, nanotechnology has been successfully applied.
Emergent cosmology in 4D Einstein Gauss Bonnet theory of gravity
Authors: Gohain Mrinnoy M , Bhuyan Kalyan
Published: May 2024

In this paper, in an FLRW background and a perfect fluid equation of state, we explore the possibility of the realization of an emergent scenario in a 4D regularized extension of Einstein-Gauss-Bonnet gravity, with the field equations particularly expressed in terms of scalar-tensor degrees of freedom. By assuming non-zero spatial curvature (k = ± 1), the stability of the Einstein static universe (ESU) and its subsequent exit into the standard inflationary scenario is tested through different approaches. In terms of dynamical systems, a spatially closed universe rather than an open universe shows appealing behaviour to exhibit a graceful transition from the ESU to standard cosmological history. We found that under linear homogeneous perturbations, for some constraints imposed on the model parameters, the ESU is stable under those perturbations. Moreover, it is noted that for a successful graceful transition, the equation of state ω must satisfy the conditions −1 < ω < 0 and ω < − 1 for closed and open universes, respectively. Furthermore, the ESU is seen to be neutrally stable under matter perturbation in the Newtonian gauge.
A discretization-free deep neural network-based approach for advection-dispersion-reaction mechanisms
Authors: Uslu Tuna Hande , Sari Murat , Cosgun Tahir
Published: May 2024

This study aims to provide insights into new areas of artificial intelligence approaches by examining how these techniques can be applied to predict behaviours for difficult physical processes represented by partial differential equations, particularly equations involving nonlinear dispersive behaviours. The current advection-dispersion-reaction equation is one of the key formulas used to depict natural processes with distinct characteristics. It is composed of a first-order advection component, a third-order dispersion term, and a nonlinear response term. Using the deep neural network approach and accounting for physics-informed neural network awareness, the problem has been elaborately discussed. Initial and boundary conditions are added as constraints when the neural networks are trained by minimizing the loss function. In comparison to the existing results, the approach has produced qualitatively correct kink and anti-kink solutions, with losses often remaining around 0.01%. It has also outperformed several traditional discretization-based methods.
Invariant analysis of the two-cell tumor growth model in the brain
Authors: Hussain Akhtar , Usman Muhammad , Zaman F D
Published: May 2024

In this study, we explore the invariance properties of a tumor growth model involving two distinct cell populations. These populations are characterized by different diffusion coefficients but share a common killing rate. This particular model serves as a representation of tumor growth within the brain. By employing the Lie group method, we unveil a two-dimensional symmetry algebra for cases where both diffusion coefficients are allowed to vary arbitrarily. Interestingly, this method reveals a nine-dimensional symmetry algebra when the diffusion coefficients are held constant. In both scenarios involving varying and constant diffusion coefficients, we conduct similarity reductions to deduce group invariant solutions, thus elucidating the model’s behavior. Notably, our findings demonstrate that the tumor’s growth remains exponential irrespective of the presence or absence of a killing rate. This remarkable phenomenon holds for various configurations of diffusion coefficients. To validate our observations, we employ Mathematica simulations, which corroborate the model’s exponential growth behavior and emphasize the role of killing rates, diffusion coefficients, and growth rate parameters in driving this exponential trend. Also, the conserved flows and conserved quantities of the model are demonstrated.