bluuebunny/crossref_metadata_2025 huggingface dataset:
The Psychological Impact of Colour and Music on Concentration
Authors: Singh Aliya , Stopforth Riaan , Rampath Amaan , Hands Clive
Published: December 2022

This paper details the research conducted as vacation work undertaken for Touch Prosthetics during which an electroencephalogram (EEG) headset was used to analyse psychological priming effects on subjects’ concentration levels using visual and audial stimuli. The experimental procedure consists of a visual aspect and an audial aspect during which a participant’s brain activity was measured when exposed to their self-reported favourite colour or music genre, respectively. The findings of both aspects of the experiment may have applications in an industrial environment as a measure to improve employee concentration, and consequently ensure health and safety by minimising hazards due to poor concentration.
Precise automated landing of a fixed-wing aircraft onto a moving platform
Authors: Parker Mohamed Zahier , Engelbrecht Jacobus Adriaan Albertus
Published: December 2022

This paper presents flight and guidance control systems that can accurately land a fixed-wing unmanned aerial vehicle onto a small moving platform. The flight control system uses a hybrid architecture that combines classical control with model predictive control. The guidance control system uses a guidance algorithm, waypoint scheduler and state machine to allow the aircraft to complete circuits around the airfield. A prediction algorithm calculates the touchdown point between the aircraft and the moving platform. The state machine provides references to the flight control system to allow the aircraft to reach this touchdown point. The control system is implemented in PX4 autopilot software and verified using simulation. A fixed-wing aircraft is constructed using a model airframe with a Pixhawk 4 autopilot hardware and other additional hardware components. In simulation, the control system lands the aircraft on a moving platform with an accuracy of 22 cm, while for the practical moving platform landing, the control system lands the aircraft with an accuracy of 75 cm. Preparations are being done to perform the final practical moving platform landing tests.
Powder Bed Defects Classification: An Industry Perspective
Authors: Du Rand Francois , Van Tonder Malan , Van Der Merwe Andre , Diegel Olaf , Hagedorn-Hansen Devon , Campbell Ian , Gibson Ian
Published: December 2022

The manufacture of defect-free parts has been a key discussion topic with the widespread adoption of additive manufacturing by industry. While significant research has been performed on the detection of powder bed defects, the focus has been on the classification of the defects according to defect type. However, when looking at creating a closed loop feedback system, it is important for the machine to make autonomous decisions regarding defects. The focus of this paper will be to create a defect severity classification matrix based on industry partner experience as well as published literature that can be used to autonomously classify defects
Environmental Impact Assessment of Reconditioning Titanium Alloy Powder
Authors: Dube Tsepo M. , van der Merwe Andre F. , Matope Stephen , Bissett Hertzog , Postma Jakkie , Makhofane Milton
Published: December 2022

The environmental impact was assessed for the spheroidisation process to compare its advantages versus mining titanium from the ground. Energy consumption was used to compare the environmental impact. With the introduction of spheroidisation at Necsa, there was a need to investigate the environmental impact of the process. The environmental impact of plasma spheroidisation making use of the 15 kW Tekna plasma system was investigated. Environmental impact assessment is part of a bigger study to investigate the holistic impact of the spheroidisation of titanium powder at Necsa. The study was carried out using ASTM standards, ensuring that the results from the experiments are acceptable. The primary focus of the paper was the 15-kW spheroidisation system. The energy consumption of the reconditioning of titanium alloys was compared to conventionally producing titanium. The role spheroidisation plays in the additive manufacturing lifecycle was also assessed. This life cycle assessment also included the other processes in additive manufacturing to give an overview of how the spheroidisation process can fit in and improve the additive manufacturing value stream.
Selective laser melting of CoCrMo: an evaluation of part density distribution across the build plate
Authors: Papworth S.J. , Bayode A. , Fourie J. , Kloppers CP.
Published: December 2022

Selective laser melting (SLM) employs the use of powder as the feedstock to manufacture the desired geometries in a layer-by-layer fashion. The part density of manufactured components is one factor used to evaluate part quality since the density has been shown to influence the mechanical properties of SLM components. This study investigated the effect of build location on the part density of selective laser melted CoCrMo. The results showed that the part density varied across the build platform due to the powder packing efficiency. The main role in the density variation is due to the inconsistent powder distribution and packing efficiency across the build plate, negatively affecting the part density.
Optimization of Surface Modification for Additively Manufactured AlSi10Mg Using a Vibratory Polishing Surface Finisher
Authors: Mfusi Busisiwe , Mathe-Maleboho Ntombizodwa , Makoana Washington , Popoola Patricia
Published: December 2022

Surface morphology is a significant aspect of a solid material, whether for aesthetic or functional purposes and currently, through different surface modification methods, developments have been dedicated into advancing metallic materials to improved surface characteristics. Additively manufactured aluminium alloys have demonstrated an extensive choice of appropriate characteristics for different uses desired for the aviation and space industry. However, the surface hardness and tribological properties are insufficient in these materials due to the fact that when one property is enhanced one is compromised especially after thermal treatment. This makes the significant development and modification of the surface properties very imperative for existing and forthcoming engineering applications. There are many types of surface modification techniques used, in this paper an optimization of the barrel finishing that uses ceramic polishing media for commercially build SLM produced AlSi10Mg will be explored. Gloss value, surface roughness and other characteristics will be characterized.
Numerical simulation of the effect of angular misalignment on the dynamic behaviour of bearing
Authors: Mashiyane Themba , Desai Dawood , Tartibu Lagouge
Published: December 2022

Bearing has been used extensively in numerous applications and their unplanned failure has a consequential effect on the smooth operation of the machinery. A slight misalignment in bearing has a detrimental effect on the smooth running of most machines. Hence, the paper leverages finite element technique to simulate the consequential effect of different degrees (0.1°, 0.2°, 0.3°, 0.4°, 0.5°) of misalignment on the dynamic behaviour of a cylindrical roller bearing subjected to typical operating conditions of an airflow root blower. The results of the study show that during operation, the temperature and Hertzian stress developed increased with an increase in the degree of misalignment and operating/rotating speed, and the maximum Hertzian stress was developed on the outer ring of the bearing in all the degrees of misalignments and operational speeds considered. Thus, making the outer ring of the bearing component, the most prone to failure during operation in the presence of misalignment.
Structural and mechanical properties of monazite type LnPO4 (Ln = La, Ce, Pr and Nd)
Authors: Motsomone Lebogang , Diale Ramogohlo , Ngoepe Phuti , Koen Renier , Chauke Hasani
Published: December 2022

Monazite, as a source of raw materials, plays a significant role in the development and applications of green technologies, including medicine and energy production. It contains nuclear materials, which are challenging to extract by convectional cracking processes. However, a new method (thermal plasma cracking) has been proposed for processing monazite. The first principles calculation approach was used to investigate the theoretical structure and mechanical properties of monazite-systems to gain deeper understanding of monazite's thermodynamics and mechanical structure. The calculated lattice parameters were found to correlate well with obtained experimental values and that these monazite type systems are exceptionally mechanically stable. The results also show that there are imaginary soft modes in dispersion curves which may correspond to negative elastic constant C35 indicating vibrational instability.
Radiopraxis
Authors: Huber Evelyn
Published: December 2022

Liebe Leserinnen und Leser,

als ich von der Thieme-Projektmanagerin die Einladung zum Verfassen dieses Editorials
bekam, musste ich schmunzeln. Zwei CPD-Artikel sowie ein Artikel in der Rubrik Aus-
und Weiterbildung haben arbeits- bzw. ausbildungstechnisch Grazer Wurzeln. Ich bin
mittlerweile schon seit über 10 Jahren in der Hochschullehre und Forschung
tätig und der Bedarf an Radiologietechnolog*innen in
Österreich steigt, wie auch in anderen Ländern, rasant. Es freut
mich, dass ich als Bildungsbeauftragte Studierenden Wissen vermitteln, praktische
Erfahrungen weitergeben und ihre Entwicklung begleiten darf. Ich bin stolz, wenn
sich diese – auch Jahre nach ihrem erfolgreichen Studiums- und
Ausbildungsabschluss – bereit erklären, einen Artikel für
die Radiopraxis zu verfassen. Denn schlussendlich haben sie während des
Studiums und auch in der Berufswelt vom Wissen erfahrener Berufskolleg*innen
profitiert und erkannt, dass sie bereits so viel Wissen/Erfahrungen
gesammelt haben, dass sie dieses wiederum weitergegeben können. Im
Fachjargon wird von Wissenstransfer gesprochen. Wenn durch die Interaktion von
implizitem (z. B. Erfahrungs-/Praxiswissen) und explizitem Wissen
(z. B. Theoriewissen) neues Wissen geschaffen wird, wird dies als
Wissensspirale bezeichnet.
Editorial
Authors: Stefanski Ana-Luisa , Dörner Thomas
Published: December 2022

Liebe Kolleginnen und Kollegen

Gemeinsam mit allen Autoren des vorliegenden Heftes, freuen wir uns, Ihnen aktuelle
Aspekte zu Veränderungen im Bereich der Gerinnung bei entzündlich
rheumatischen Erkrankungen vorzustellen. Die Komplexität im Bereich der
Rheumatologie beinhaltet unterschiedliche Aktivierungszustände des
Immunsystems, welche über humorale und zelluläre Mechanismen im
Rahmen der Körperabwehr auch mit Gerinnungsaktivierung einhergehen
können. Gut bekannt sind die Arthropathie bei Hämophiliepatienten,
bei denen die sog. „Annual Bleeding Rates“ in Gelenke durch
adäquate Faktorensubstution und schließlich den
Möglichkeiten der Gentherapien revolutionär erniedrigt wurden.
Das Erleben Geistlicher Trockenheit als Glaubens- und Lebenskrise und ihre Bedeutung für die psychotherapeutische Begleitung
Authors: Büssing Arndt
Published: December 2022

Manche Lebenskrisen sind so tiefgreifend, dass sie einer professionellen psychotherapeutischen Begleitung bedürfen. Und manche Glaubenskrisen sind so belastend, dass sie einer psychotherapeutischen und geistlichen Begleitung sowie Einordnung bedürfen, um sie von der Depression abgrenzen zu können. In der Tat gibt es eine Schnittmenge zwischen dem Erleben von Phasen „Geistlicher Trockenheit“ als Ausdruck einer spezifischen Form der religiösen Verunsicherung einerseits und depressiver Gestimmtheit, emotionaler Erschöpfung sowie Verlust einer Lebensstimmigkeit andererseits. Das Erleben solcher geistlichen „Wüsten- und Dürrezeiten“ soll ausdrücklich nicht pathologisiert werden. Nicht jede Phase Geistlicher Trockenheit ist eine Depression und nicht jede Depression ist Ausdruck einer „Dunklen Nacht der Seele“ im Sinne eines „Läuterungsprozesses“, wie es der Mystiker des Mittelalters Johannes vom Kreuz beschrieb. In diesem Beitrag soll es um die Einordnung und Nachvollziehbarkeit des Erlebens gehen. Hierfür werden empirische Daten und qualitative Befunde erörtert.
Die Rolle von Religiosität und Spiritualität im Umgang mit der Erkrankung bei psychiatrischen Patienten in Kroatien und Bosnien und Herzegowina
Authors: Glavas Andrijana , Büssing Arndt , Baumann Klaus
Published: December 2022

Im Rahmen einer Querschnittserhebung in den Universitätskliniken von Zagreb (HR) und Sarajevo (BiH) unter Patienten mit PTBS und anderen Traumafolgeerkrankungen (TFE) sowie anderen psychischen Erkrankungen (n = 353) gehen wir der Frage nach, wie die Religiosität/Spiritualität (R/S) der Betroffenen und die empfundene Krankheitsbelastung zusammenhängen. Es zeigte sich, dass die Krankheitsbelastung bei Personen mit TFE signifikant höher war als mit anderen psychischen Erkrankungen. Zwischen ihnen besteht kein signifikanter Unterschied in der Nutzung ihrer R/S als Ressource im Umgang mit ihrer Erkrankung (SpREUK-Fragebogen). Die SpREUK-Faktoren unterscheiden sich jedoch signifikant in Abhängigkeit von der Behandlungsdauer. Wer nicht aktiv am Krieg teilnahm suchte weit mehr nach einer spirituellen Ressource, hatte größeres religiöses Vertrauen und sah Krankheit deutlich eher als eine Chance für (mögliche) Veränderung im eigenen Leben als die Kriegsteilnehmer. Bei Personen mit TFE-korreliert die Stärke der Krankheitsbelastung moderat (r > 0,40) mit allen 3 SpREUK-Faktoren, wohingegen dies nur schwach bei Personen mit anderen psychisch Erkrankten der Fall ist. Bei aktiver Kriegsteilnahme korreliert eine höhere subjektive Krankheitsbelastung ähnlich (moderat) mit einer stärkeren Suche und mehr religiösem Vertrauen in, schwächer hingegen mit der Reflexion. Die Rolle der R/S im Umgang mit der eigenen Erkrankung kann zeitlichen und biografischen Schwankungen bzw. dynamischen Entwicklungen unterliegen, bedeutet aber für die meisten eine bedeutsame Ressource. Ihre Beachtung im therapeutischen Prozess birgt über die beiden Länder hinaus Potenziale für Public Health.
Catalytic Enantioselective Inverse-Electron-Demand Diels–Alder Reaction of 2-Pyrones and Vinyl Selenides
Authors: Cai Quan , You Xin-Yu
Published: December 2022

We report an asymmetric inverse-electron-demand Diels–Alder reaction of electron-deficient 2-pyrones with various phenyl vinyl selenides catalyzed by a chiral bis(oxazoline)/Cu(OTf)2 complex. By using a side-arm-modified chiral bis(oxazoline)ligand, a variety of [2,2,2]-bicyclic lactones with phenyl selenide substituents were obtained in good to excellent yields (up to 99%) and enantioselectivities (up to 98% ee) under mild conditions. Based on this strategy, a highly concise enantioselective synthesis of the Corey lactone was accomplished.
Trends in Attempted Vaginal Delivery among Pregnancies Complicated by Gastroschisis, 2014 to 2020
Authors: Schmidt Christina N. , Wen Timothy , Friedman Alexander M. , D'Alton Mary E. , Andrikopoulou Maria
Published: December 2022

Objective Gastroschisis is a full-thickness congenital defect of the abdominal wall through which intestines and other organs may herniate. In a prior analysis, attempted vaginal delivery with fetal gastroschisis appeared to increase through 2013, although cesarean delivery remained common. The objective of this analysis was to update current trends in attempted vaginal birth among pregnancies complicated by gastroschisis.

Study Design We performed an updated cross-sectional analysis of live births from 2014 and 2020 using data from the U.S. National Vital Statistics System and evaluated trends in attempted vaginal deliveries among births with gastroschisis. Trends were evaluated using joinpoint regression. We constructed logistic regression models to evaluate the association between demographic and clinical variables and attempted vaginal delivery in the setting of gastroschisis.

Results Among 5,355 deliveries with gastroschisis meeting inclusion criteria, attempted vaginal delivery increased significantly from 68.9% to 75.1%, an average annual percent change of 1.7% (95% confidence interval [CI], 0.8–2.5). Among gastroschisis-complicated pregnancies, patients 35 to 39 years old (adjusted odds ratio [aOR], 0.53; 95% CI, 0.37–0.79) and Hispanic race/ethnicity (aOR, 0.69; 95% CI, 0.58–0.62) were at lower likelihood of attempted vaginal delivery in adjusted analyses.

Conclusion These findings suggest that vaginal delivery continues to increase in the setting of gastroschisis. Further reduction of surgical delivery for this fetal defect may be possible.

Key Points
The Synthetic Approaches to 1,2-Chlorohydrins
Authors: Hilt Gerhard
Published: December 2022

This short review highlights the hitherto realised synthetic approaches towards organic 1,2-chlorohydrins by functionalisation of alkenes (i.e., 1,2-chlorohydroxylation), which is the most prominent access route to this class of compounds. Also, some other synthetic approaches involving the reduction of α-chloroketones, the epoxide opening ring by chloride anions and the utilisation of Grignard reagents for the synthesis of these compounds and chlorination of allylic alcohols are highlighted. Finally, enzymatic reactions for the formation of chlorohydrins are briefly summarised followed by a short view on natural products containing this moiety.

1 Introduction

2 Applications for the Synthesis of 1,2-Chlorohydrins

2.1 Chlorohydroxylation of Alkenes

2.2 Reduction of Chloroketones

2.3 Metalorganic Reagents

2.4 Epoxide Ring Opening

2.5 Chlorination of Allylic Alcohols

2.6 Biochemical Methods

2.7 Selected Applications in Natural Product Total Synthesis

3 Conclusion
Sensitivity and Specificity of the Newborn Infant Parasympathetic Evaluation Index in Pain Assessment of Very Low Birth Weight Infants
Authors: Uberos Jose , Campos-Martinez Ana , Ruiz-López Aida , Fernandez-Marín Elizabeth , García-Serrano Jose Luis
Published: December 2022

Objective This article describes the results of a study investigating the sensitivity and specificity of the Newborn Infant Parasympathetic Evaluation (NIPE) index for detecting the physiological changes resulting from nociception in painful procedures in very low birth weight (VLBW) infants.

Study Design A prospective observational study was carried on of 44 newborns at 23 to 32 weeks' gestational age. The sensitivity and specificity of the NIPE index are analyzed using a receiver operating characteristic curve. Most of the painful procedures performed were skin-lancing and venipunctures. Nonpainful procedures consist of no intervention, with an interval of at least 1 hour with painful procedures in each newborn.

Results The accuracy of the NIPE index to diagnose mild nociceptive stimulation in VLBW newborns is 73.2%.

Conclusion The NIPE index is a useful technique for assessing nociceptive stimulation in newborns, presenting less observer-dependent variability than other pain assessment scales.

Key Points
Liouville-type theorems for the stationary compressible barotropic and incompressible inhomogeneous Navier–Stokes equations
Authors: Liu Pan
Published: December 2022

The present paper is dedicated to the Liouville-type problem for the three-dimensional stationary compressible barotropic Navier–Stokes equations and incompressible inhomogeneous Navier–Stokes equations. We show that velocity u is trivial under some suitable assumptions stated in terms of BMO−1 spaces.
Slow passage through a Hopf-like bifurcation in piecewise linear systems: Application to elliptic bursting
Authors: Penalva J. , Desroches M. , Teruel A. E. , Vich C.
Published: December 2022

The phenomenon of slow passage through a Hopf bifurcation is ubiquitous in multiple-timescale dynamical systems, where a slowly varying quantity replacing a static parameter induces the solutions of the resulting slow–fast system to feel the effect of the Hopf bifurcation with a delay. This phenomenon is well understood in the context of smooth slow–fast dynamical systems; in the present work, we study it for the first time in piecewise linear (PWL) slow–fast systems. This special class of systems is indeed known to reproduce all features of their smooth counterpart while being more amenable to quantitative analysis and offering some level of simplification, in particular, through the existence of canonical (linear) slow manifolds. We provide conditions for a PWL slow–fast system to exhibit a slow passage through a Hopf-like bifurcation, in link with possible connections between canonical attracting and repelling slow manifolds. In doing so, we fully describe the so-called way-in/way-out function. Finally, we investigate this slow passage effect in the Doi–Kumagai model, a neuronal PWL model exhibiting elliptic bursting oscillations.
Performance improvement of space-resolved extreme ultraviolet spectrometer by use of complementary metal-oxide semiconductor detectors at the Experimental Advanced Superconducting Tokamak
Authors: Cheng Yunxin , Zhang Ling , Morita Shigeru , Hu Ailan , Wu Zhenwei , Xu Zong , Duan Yanmin , Xu Liqing , Zhong Long , Zhang Fengling , Zhang Wenmin , Zhao Zihang , Zhao Weikuan , Li Zhengwei , Liu Haiqing
Published: December 2022

Two pairs of space-resolved extreme ultraviolet (EUV) spectrometers working at 5–138 Å with different vertical observation ranges of −7 ≤ Z ≤ 19 and −18 ≤ Z ≤ 8 cm have been newly developed to observe the radial profile of impurity line emissions and to study the transport of high-Z impurity ions intrinsically existing in EAST tokamak plasmas. Both spectrometers are equipped with a complementary metal-oxide semiconductor (CMOS) detector (Andor Marana-X 4.2B-6, Oxford Instruments) with sensitive area of 13.3 × 13.3 mm2 and number of pixels equal to 2048 × 2048 (6.5 × 6.5 µm2/pixels). Compared to the currently operating space-resolved EUV spectrometers with a charge-coupled detector (CCD: 1024 × 255 pixels, 26 × 26 µm2) working at 30–520 Å, this spectrometer’s performance was substantially improved by using the CMOS detector. First, the spectral resolution measured at full width at half maximum was improved in the whole wavelength range, e.g., Δλ1/2_CMOS = 0.092 Å and Δλ1/2_CCD = 0.124 Å at C VI 33.73 Å and Δλ1/2_CMOS = 0.104 Å and Δλ1/2_CCD = 0.228 Å at Mo XXXI 115.999 Å, thus enabling a more accurate analysis of spectra with complicated structure such as tungsten unresolved transition array in the range 45–65 Å. Second, the temporal resolution was largely improved due to the high-speed data acquisition system of the CMOS detector, e.g., Δt_CMOS = 15 ms/frame and Δt_CCD = 200 ms/frame at routine operation in the radial profile measurement. Third, signal saturation issues that occurred when using the old CCD sensor during impurity accumulation now disappeared entirely using the CMOS detector due to lower exposure time at high readout rates, which largely improved the observation performance in similar impurity burst events. The above-mentioned performance improvements of the space-resolved EUV spectrometer led to a rapid change in the W XXXIII (52.22 Å) radial profile during a single cycle of low-frequency sawtooth oscillation with fst = 5–6 Hz at a sufficient detector count rate.
Global existence of smooth solutions to a full Euler–Poisson system in one space dimension
Authors: Liu Cunming
Published: December 2022

When a strictly dissipative term arises in the energy equation, the Cauchy problem for Euler–Poisson systems admits global smooth solutions for small initial data. This was proved in previous studies. In this paper, we study a stability problem for a full Euler–Poisson system without dissipation in the energy equation. We prove the global existence of smooth solutions near constant equilibrium states in one space dimension. The stability results are obtained for both one-fluid and two-fluid Euler–Poisson systems. In our proof of these results, we show an L2 energy equality in Euler coordinates. Then, we establish energy estimates of derivatives of the solution in Lagrangian coordinates by a characteristic technique. These estimates together with the equivalence of smooth solutions between the two coordinates yield the global existence of the solution.
Investigation of long-term light stability of negative charge injected into oxide-nitride-oxide passivation stack of crystalline silicon solar cells
Authors: Chen Christopher , Hwang Jeong-Mo , Ok Young-Woo , Choi Wook-Jin , Upadhyaya Vijaykumar , Rounsaville Brian , Rohatgi Ajeet
Published: December 2022

A negatively charged oxide-nitride-oxide stack for field-effect passivation of crystalline silicon solar cells is discussed. The negative charge was injected into the stack by a plasma charge injection technology. Charge stability was studied by exposing samples to AM1.5 simulation visible light and full-spectrum light at temperatures ranging from 55 to 78 °C for up to 300 h. Charge injection and loss were quantified based on shifts in the flatband voltage of capacitance–voltage curves measured with a mercury probe. The most probable mechanism of charge loss was found to be diffusion of negative charged hydrogen atoms through nitride and bottom oxide. The optimum recipe for each layer of the stack was investigated to minimize the loss of injected charge. The flatband voltage decay of the optimized stack was found to fit a power-law trend, suggesting the dispersive transport of hydrogen atoms with a dispersion parameter of ∼0.06–0.07. The optimized stack is projected to maintain a negative charge density of about 3.6 × 1012 cm−2 or more after 25 years of field operation in an environment such as Arizona, which would be sufficient for field-effect passivation under one-sun illumination. The high stability of the negative injected charge makes the plasma charging technology a safer and lower cost alternative to Al2O3-passivation technology commonly used to passivate p-type surfaces.
Forecasting and diagnostics of critical states in platform-vibrator with shock
Authors: Lizunov P. , Pogorelova O. , Postnikova T.
Published: December 2022

A platform-vibrator with shock is a low-frequency machine used in the construction industry for compaction and molding of large concrete products. Its mathematical model is a two-degree-of-freedom two-body vibro-impact system with a soft impact. Some changes in its parameters can increase the machine performance and improve the product quality, but these same changes may lead to the emergence of critical states, such as coexisting regimes in hysteresis zone, chaotic motion, intermittency and crisis-induced intermittency, crises, and transient chaos. Some of them can be undesirable and dangerous. This article shows their diagnostics and recognition, the possibility of their prediction, as well as the criterion determining the set of parameter ranges where critical states can occur. Diagnostics is carried out both by traditional tools and by the less common ones, such as the construction of fractal structures and wavelet characteristics.
Surface trap characteristics of polyimide and effect of surface charge accumulation on surface flashover
Authors: Li Guochang , Hu Kai , Sun Weixin , Wei Yanhui , Li Shengtao , Lei Qingquan
Published: December 2022

Charge accumulation on the surface of insulation dielectric used in high voltage DC equipment is one of the important causes of surface flashover. Surface charge accumulation is closely related to surface trap characteristics. In this paper, the surface trap energy level distribution of polyimide (PI) was calculated and analyzed by the corona charging method and surface potential decay method. Besides, electron and hole trap characteristics were studied by changing the polarity and amplitude of the charging voltage. Furthermore, the influence of surface charge polarity and quantity on the flashover voltage was researched. Experimental results indicate that the energy level of traps corresponding to the maximum trapped charge density ranges around 0.94 eV. In addition, the energy level of the hole trap is slightly higher than that of the electron trap. The maximum charge density captured by the electron trap and hole trap is about 1.17 × 1021 and 1.03 × 1021 eV−1 m−3, respectively. The polarity of the surface charge can influence the conductivity characteristics of PI, the surface heterocharge reduces the volume conductivity by about 80% while the surface homocharge improves the volume conductivity of PI by about 6.4 times. Besides, both negative and positive surface charges can improve surface conductivity. The polarity of surface charge influences the flashover characteristics of PI, the flashover voltage increases by about 37.8% with the increase of homocharge density and decreases by about 23.8% with the increase of heterocharge density, which is related to the change of electric field near the cathode caused by surface charge accumulation.
Dissipative solitons stabilized by nonlinear gradient terms: Time-dependent behavior and generic properties
Authors: Descalzi Orazio , Carvalho M. I. , Facão M. , Brand Helmut R.
Published: December 2022

We study the time-dependent behavior of dissipative solitons (DSs) stabilized by nonlinear gradient terms. Two cases are investigated: first, the case of the presence of a Raman term, and second, the simultaneous presence of two nonlinear gradient terms, the Raman term and the dispersion of nonlinear gain. As possible types of time-dependence, we find a number of different possibilities including periodic behavior, quasi-periodic behavior, and also chaos. These different types of time-dependence are found to form quite frequently from a window structure of alternating behavior, for example, of periodic and quasi-periodic behaviors. To analyze the time dependence, we exploit extensively time series and Fourier transforms. We discuss in detail quantitatively the question whether all the DSs found for the cubic complex Ginzburg–Landau equation with nonlinear gradient terms are generic, meaning whether they are stable against structural perturbations, for example, to the additions of a small quintic perturbation as it arises naturally in an envelope equation framework. Finally, we examine to what extent it is possible to have different types of DSs for fixed parameter values in the equation by just varying the initial conditions, for example, by using narrow and high vs broad and low amplitudes. These results indicate an overlapping multi-basin structure in parameter space.
Tuning superconductivity of Bi2Sr2CaCu2O8+x by fluoride ion intercalation with LaF3 gate dielectric
Authors: Wang Heng , Cao Zongzheng , Zhu Yuying , Liao Menghan , Gu Genda , Xue Qi-Kun , Zhang Ding
Published: December 2022

We demonstrate fluorine intercalation into Bi2Sr2CaCu2O8+x (BSCCO) flakes, as thick as 100 nm, by back-gating a single crystalline LaF3 substrate. Element-sensitive analysis not only confirms the presence of fluorine in BSCCO after gating but also reveals lateral diffusion of fluorine in BSCCO. Transport measurements further demonstrate the hole-doping effect of fluoride ions in BSCCO through effective modulation of the superconducting transitions. Our work introduces a distinct type of ions (F−) that can be intercalated into materials via solid state back-gating. It broadens the toolbox of ion back-gating and is useful for addressing exotic phenomena in the heavily hole doped regime.
Chaotic heteroclinic networks as models of switching behavior in biological systems
Authors: Morrison Megan , Young Lai-Sang
Published: December 2022

Key features of biological activity can often be captured by transitions between a finite number of semi-stable states that correspond to behaviors or decisions. We present here a broad class of dynamical systems that are ideal for modeling such activity. The models we propose are chaotic heteroclinic networks with nontrivial intersections of stable and unstable manifolds. Due to the sensitive dependence on initial conditions, transitions between states are seemingly random. Dwell times, exit distributions, and other transition statistics can be built into the model through geometric design and can be controlled by tunable parameters. To test our model’s ability to simulate realistic biological phenomena, we turned to one of the most studied organisms, C. elegans, well known for its limited behavioral states. We reconstructed experimental data from two laboratories, demonstrating the model’s ability to quantitatively reproduce dwell times and transition statistics under a variety of conditions. Stochastic switching between dominant states in complex dynamical systems has been extensively studied and is often modeled as Markov chains. As an alternative, we propose here a new paradigm, namely, chaotic heteroclinic networks generated by deterministic rules (without the necessity for noise). Chaotic heteroclinic networks can be used to model systems with arbitrary architecture and size without a commensurate increase in phase dimension. They are highly flexible and able to capture a wide range of transition characteristics that can be adjusted through control parameters.
Room-temperature multiferroicity in GaFeO3 thin film grown on (100)Si substrate
Authors: Goswami Sudipta , Mishra Shubhankar , Dana Kausik , Kumar Mandal Ashok , Dey Nitai , Pal Prabir , Satpati Biswarup , Mukhopadhyay Mrinmay , Kumar Ghosh Chandan , Bhattacharya Dipten
Published: December 2022

Room-temperature magnetoelectric multiferroicity has been observed in c-axis oriented GaFeO3 thin films (space group Pna21), grown on economic and technologically important (100)Si substrates by a pulsed laser deposition technique. Structural analysis and comprehensive mapping of the Ga:Fe ratio across a length scale range of 104 reveals coexistence of epitaxial and chemical strain. It induces formation of finer magnetic domains and large magnetoelectric coupling—a decrease in remanent polarization by ∼21% under ∼50 kOe. Magnetic force microscopy reveals the presence of both finer (<100 nm) and coarser (∼2 μm) magnetic domains. Strong multiferroicity in epitaxial GaFeO3 thin films, grown on a (100)Si substrate, brighten the prospect of their integration with Si-based electronics and could pave the way for development of economic and more efficient electromechanical, electrooptic, or magnetoelectric sensor devices.
Enhanced directional extraction of very cold neutrons using a diamond nanoparticle powder reflector
Authors: Chernyavsky S. M. , Dubois M. , Korobkina E. , Lychagin E. V. , Muzychka A. Yu. , Nekhaev G. V. , Nesvizhevsky V. V. , Nezvanov A. Yu. , Strelkov A. V. , Zhernenkov K. N.
Published: December 2022

For more than a decade, detonation nanodiamond (DND) powders have been actively studied as a material for efficient reflectors of very cold neutrons (VCNs) and cold neutrons. In this work, we experimentally demonstrate, for the first time, the possibility of enhanced directional extraction of a VCN beam using a reflector made of fluorinated DND powder. With respect to the theoretical flux calculated from an isotropic source at the bottom of the reflector cavity, the gain in the VCN flux density along the beam axis is ∼10 for the neutron velocities of ∼57 and ∼75 m/s. The use of such reflectors for enhanced directional extraction of VCN from neutron sources will make it possible to noticeably increase the neutron fluxes delivered to experiments and expand the scope of VCN applications.
Nonlinear dynamics of discontinuous uncertain oscillators with unilateral constraints
Authors: Fu Chao , Zheng Zhaoli , Zhu Weidong , Xie Zhongliang , Qin Weiyang , Lu Kuan
Published: December 2022

Nonlinear dynamics of discontinuous oscillators with unilateral constraints and non-random parametric uncertainties are investigated. Nonlinear oscillators considering single- and double-sided constraints are carefully constructed to exhibit rich bifurcations, such as period-doubling and Neimark–Sacker bifurcations. In deterministic amplitude–frequency responses, both hardening and softening effects are induced by non-smooth contact-type nonlinearities. Stabilities of the solutions are determined by the shooting method and the monodromy matrix. To effectively quantify the behaviors of nonlinear oscillators in the presence of parametric uncertainties, a non-intrusive surrogate function aided by arc-length ratio interpolation is constructed. Simulation results demonstrate variabilities of nonlinear responses under different non-random uncertainties. Moreover, an accuracy verification is provided to verify the effectiveness of the non-intrusive uncertainty propagation method. It is found that the surrogate function in combination with the arc-length ratio technique has high accuracy and evolutions of turning points are captured satisfactorily regardless of complex interactions of nonlinearities and uncertainties. The findings and methodologies reported are meaningful to general nonlinear systems having complex motions, paving the road for more in-depth investigations into uncertain nonlinear dynamics.
Experimental analysis of direct contact condensation during vertical injection of steam onto a subcooled water pool
Authors: Patel Saurabh , Guleria Sharey Deep , Pati Aniket , Kumar Parmod
Published: December 2022

Experiments have examined the phenomenon of direct contact condensation when steam is injected vertically into the subcooled water pool. The investigation is carried out by varying the steam mass flow rate and submergence depth of the steam injection pipe in the range of 10–50 kg/h and 1–13 cm, respectively. The behavior of the bubble that appeared at the pipe outlet, transient heat transfer coefficient, pressure variation in the steam injection pipe, and its associated frequency have been analyzed. The images captured by high-speed camera showed different bubble shapes. The overall cycle time of bubble evolution has decreased with an increase in the mass flow rate and increased with an increase in the pipe submergence depth. The time-averaged heat transfer coefficient increased with an increase in the mass flow rate and decreased with the rise of the pipe submergence depth. The pressure drop within the steam injection pipe shows the parabolic variation with an increase in the mass flow rate and is slightly influenced by the submergence depth due to changes in interfacial structures within the pipe. The peak frequency associated with the pressure has increased with an increase in the mass flow rate and decreased with an increase in the pipe submergence depth at higher mass flow rates. The fast Fourier transform of interfacial area of the larger bubble at the pipe outlet shows that the first peak frequency lies between 0.5 and 5 Hz, and the second peak frequency lies in the range of 25–30 Hz.
(β-deformed) Hurwitz–Kontsevich model and affine Yangian of gl(1)
Authors: Wang Na
Published: December 2022

In this paper, we use the affine Yangian of gl(1) to describe the (β-deformed) Hurwitz–Kontsevich model. We find that the W-operators of the (β-deformed) Hurwitz–Kontsevich model can be represented by the generators ek, fk of the affine Yangian of gl(1), and their actions on Schur functions or Jack polynomials can be obtained from the 3D Young diagram representation of the affine Yangian of gl(1).
Spin-wave spectra in antidot lattice with inhomogeneous perpendicular magnetic anisotropy
Authors: Moalic M. , Krawczyk M. , Zelent M.
Published: December 2022

Magnonic crystals are structures with periodically varied magnetic properties that are used to control collective spin-wave excitations. With micromagnetic simulations, we study spin-wave spectra in a 2D antidot lattice based on a multilayered thin film with perpendicular magnetic anisotropy (PMA). We show that the modification of the PMA near the antidot edges introduces interesting changes to the spin-wave spectra, even in a fully saturated state. In particular, the spectra split into two types of excitations: bulk modes with amplitude concentrated in a homogeneous part of the antidot lattice and edge modes with an amplitude localized in the rims of reduced PMA at the antidot edges. Their dependence on the geometrical or material parameters is distinct, but at resonance conditions fulfilled, we found strong hybridization between bulk and radial edge modes. Interestingly, the hybridization between the fundamental modes in bulk and rim is of magnetostatic origin, but the exchange interactions determine the coupling between higher-order radial rim modes and the fundamental bulk mode of the antidot lattice.
Reconstructing turbulent velocity information for arbitrarily gappy flow fields using the deep convolutional neural network
Authors: Zhang Fan , Hu Haibao , Ren Feng , Zhang Heng , Du Peng
Published: December 2022

Detailed and reliable flow information is the basis for understanding and further mediating turbulent flows. Due to experimental limitations, such as the absence of seeding particles owing to an inhomogeneous tracer distribution or obstructed optical paths, gappy flow-field data frequently appear with diverse shapes. To resolve this problem, we propose herein the use of a convolutional neural network (CNN) model to reconstruct the velocity field with the missing information of wall-confined turbulent flows. We consider the example of a turbulent channel flow with a frictional Reynolds number Reτ=180 and use machine learning to attain the given objective. High-fidelity numerical data obtained by direct numerical simulation based on the lattice Boltzmann equation are used to generate the datasets required for network training, where data in randomly located square or rectangular regions are masked to provide a maximally realistic instantaneous gappy flow field. The results show that the missing information in gappy regions can be effectively reconstructed for both instantaneous and temporally continuous flow fields. Furthermore, the results are insensitive to the missing locations, even if the locations vary with time. The L2 relative error of the reconstructed instantaneous flow field is generally around 2%. Furthermore, an analysis based on the kinetic-energy spectrum and proper orthogonal decomposition verifies that the reconstructed data are physically consistent with the ground truth. The extracted dominating modes have a maximum relative error level of 10−3. The results obtained herein verify that the proposed CNN model provides complete and reliable data for gappy flows and are physically consistent with physical data.
Comprehensive evaluation of human-derived anti-poly-GA antibodies in cellular and animal models of
C9orf72
disease
Authors: Jambeau Melanie , Meyer Kevin D. , Hruska-Plochan Marian , Tabet Ricardos , Lee Chao-Zong , Ray-Soni Ananya , Aguilar Corey , Savage Kitty , Mishra Nibha , Cavegn Nicole , Borter Petra , Lin Chun-Chia , Jansen-West Karen R. , Jiang Jie , Freyermuth Fernande , Li Nan , De Rossi Pierre , Pérez-Berlanga Manuela , Jiang Xin , Daughrity Lilian M. , Pereira João , Narayanan Sarav , Gu Yuanzheng , Dhokai Shekhar , Dalkilic-Liddle Isin , Maniecka Zuzanna , Weber Julien , Workman Michael , McAlonis-Downes Melissa , Berezovski Eugene , Zhang Yong-Jie , Berry James , Wainger Brian J. , Kankel Mark W. , Rushe Mia , Hock Christoph , Nitsch Roger M. , Cleveland Don W. , Petrucelli Leonard , Gendron Tania F. , Montrasio Fabio , Grimm Jan , Polymenidou Magdalini , Lagier-Tourenne Clotilde
Published: December 2022

Hexanucleotide G
4
C
2
repeat expansions in the
C9orf72
gene are the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia. Dipeptide repeat proteins (DPRs) generated by translation of repeat-containing RNAs show toxic effects in vivo as well as in vitro and are key targets for therapeutic intervention. We generated human antibodies that bind DPRs with high affinity and specificity. Anti-GA antibodies engaged extra- and intra-cellular poly-GA and reduced aggregate formation in a poly-GA overexpressing human cell line. However, antibody treatment in human neuronal cultures synthesizing exogenous poly-GA resulted in the formation of large extracellular immune complexes and did not affect accumulation of intracellular poly-GA aggregates. Treatment with antibodies was also shown to directly alter the morphological and biochemical properties of poly-GA and to shift poly-GA/antibody complexes to more rapidly sedimenting ones. These alterations were not observed with poly-GP and have important implications for accurate measurement of poly-GA levels including the need to evaluate all centrifugation fractions and disrupt the interaction between treatment antibodies and poly-GA by denaturation. Targeting poly-GA and poly-GP in two mouse models expressing G
4
C
2
repeats by systemic antibody delivery for up to 16 mo was well-tolerated and led to measurable brain penetration of antibodies. Long-term treatment with anti-GA antibodies produced improvement in an open-field movement test in aged
C9orf72
450
mice. However, chronic administration of anti-GA antibodies in AAV-(G
4
C
2
)
149
mice was associated with increased levels of poly-GA detected by immunoassay and did not significantly reduce poly-GA aggregates or alleviate disease progression in this model.
Tracking water dimers in ambient nanocapsules by vibrational spectroscopy
Authors: Hwang Alexander Y. , Chikkaraddy Rohit , Grys David-Benjamin , Scherman Oren A. , Baumberg Jeremy J. , de Nijs Bart
Published: December 2022

Nanoconfined few-molecule water clusters are invaluable systems to study fundamental aspects of hydrogen bonding. Unfortunately, most experiments on water clusters must be performed at cryogenic temperatures. Probing water clusters in noncryogenic systems is however crucial to understand the behavior of confined water in atmospheric or biological settings, but such systems usually require either complex synthesis and/or introduce many confounding external bonds to the clusters. Here, we show that combining Raman spectroscopy with the molecular nanocapsule cucurbituril is a powerful technique to sequester and analyze water clusters in ambient conditions. We observe sharp peaks in vibrational spectra arising from a single rigid confined water dimer. The high resolution and rich information in these vibrational spectra allow us to track specific isotopic exchanges inside the water dimer, verified with density-functional theory and kinetic population modeling. We showcase the versatility of such molecular nanocapsules by tracking water cluster vibrations through systematic changes in confinement size, in temperatures up to 120° C, and in their chemical environment.
Surface coating by mechanofusion modulates bulk charging pathways and battery performance of Ni-rich layered cathodes
Authors: Hou Dong , Han Jiaxiu , Geng Chenxi , Xu Zhengrui , AlMarzooqi Modhi M. , Zhang Jin , Yang Zhijie , Min Jungki , Xiao Xianghui , Borkiewicz Olaf , Wiaderek Kamila , Liu Yijin , Zhao Kejie , Lin Feng
Published: December 2022

Ni-rich layered oxides as high-capacity battery cathodes suffer from degradation at high voltages. We utilize a dry surface modification method, mechanofusion (MF), to achieve enhanced battery stability. The simplicity, high yield, and flexibility make it cost-effective and highly attractive for processing at the industrial scale. The underlying mechanisms responsible for performance improvement are unveiled by a systematic study combining multiple probes, e.g., 3D nano-tomography, spectroscopic imaging, in situ synchrotron diffraction, and finite element analysis (FEA). MF affects the bulk crystallography by introducing partially disordered structure, microstrain, and local lattice variation. Furthermore, the crack initiation and propagation pattern during delithiation are regulated and the overall mechanical fracture is reduced after such surface coating. We validate that MF can alter the bulk charging pathways. Such a synergic effect between surface modification and bulk charge distribution is fundamentally important for designing next-generation battery cathode materials.