bluuebunny/crossref_metadata_2025_split huggingface dataset:
Driver optimization of high power converter based on BIGT reverse conduction loss
Authors: Qi Lei , Li Ze , Zhang Xiangyu , Yang Jin , Lu Yuanfang , Wang Jingfei , Wen Fuyue , Wang Kefeng , Hu Xinyu 
Published: January 2024

AbstractBi‐mode Insulated Gate Transistor (BIGT), owing to its notable attributes in power density and compact dimensions, holds promising applications in the realm of high power converters. However, its characteristic of the voltage drop in diode mode controlled by gate‐emitter voltage poses significant challenges for low‐loss operation. This paper investigates the relationship between BIGT's on‐state voltage drop in diode mode and its gate‐emitter voltage in detail. By combining simulation and experimental analysis, recommended the gate‐emitter voltage values are provided. Furthermore, a novel driver optimization scheme is proposed to automatically lower the gate voltage during reverse conduction, which can effectively reduce the reverse on‐state losses of the BIGT. Experimental validation demonstrates a 10.6% reduction in reverse on‐state voltage drop, showcasing the efficacy of the proposed driver optimization scheme.
Stellar populations and the origin of thick disks in AURIGA simulations
Authors: Pinna Francesca , Walo-Martín Daniel , Grand Robert J. J. , Martig Marie , Fragkoudi Francesca , Gómez Facundo A. , Marinacci Federico , Pakmor Rüdiger 
Published: January 2024

Context. Recent integral-field spectroscopy observations of edge-on galaxies have led to significant progress in our knowledge of the ages and chemical compositions of thick disks. However, the origin of thick disks and their evolutionary connection with thin disks is still a matter of debate.
Aims. We provide new insights into this topic by connecting the stellar populations of thick disks at redshift z = 0 with their past formation and growth in 24 Milky Way-mass galaxies from the AURIGA zoom-in cosmological simulations. We assess the role played by mergers of satellite galaxies in the mass assembly of geometrically defined thick disks.
Methods. We projected each galaxy edge on and decomposed it morphologically into two disk components in order to geometrically define the thin and thick disks, as is usually done in observations of external galaxies. We produced age, metallicity, and [Mg/Fe] edge-on maps of the 24 galaxies. We quantified the impact of satellite mergers by mapping the distribution of ex situ stars.
Results. Thick disks are on average ∼3 Gyr older, ∼0.25 dex more metal poor, and ∼0.06 dex more [Mg/Fe]-enhanced than thin disks. Their average ages range from ∼6 to ∼9 Gyr, metallicities from ∼ − 0.15 to ∼0.1 dex, and [Mg/Fe] from ∼0.12 to ∼0.16 dex. These properties are the result of an early initial in situ formation, followed by a later growth driven by the combination of direct accretion of stars, some in situ star formation fueled by mergers, and dynamical heating of stars. The balance between these processes varies from galaxy to galaxy and impacts thick-disk ages and metallicities. The oldest thick disks (older than 8 Gyr) are hosted by galaxies with a low mass fraction of accreted stars (below 8%), while the youngest thick disks (younger than 7 Gyr) are found in galaxies with higher accreted fractions (larger than 25%). Mergers play a key role in the mass assembly of thick disks, contributing an average accreted mass fraction of ∼22% in the analyzed thick-disk-dominated regions. In two galaxies, about half of the geometric thick-disk mass was directly accreted. The mass fraction of accreted stars is lower than 10% only in four thick disks. While primordial thick disks form at high redshifts in all galaxies, young metal-rich thin disks, with much lower [Mg/Fe] abundances, start to form later but at different times (at higher or lower redshifts) depending on the galaxy.
Conclusions. We conclude that thick disks, although mostly formed in situ, grow thanks to the significant contribution of satellite mergers, especially through the direct accretion of stars. They result from the interplay of external processes with the internal evolution of the galaxy.
Precise photoionisation treatment and hydrodynamic effects in atmospheric modelling of warm and hot Neptunes
Authors: Kubyshkina Daria , Fossati Luca , Erkaev Nikolai V. 
Published: January 2024

Context. Observational breakthroughs in the field of exoplanets in the last decade have motivated the development of numerous theoretical models, such as those describing atmospheres and mass loss, which is believed to be one of the main drivers of planetary evolution.
Aims. We outline for which types of close-in planets in the Neptune-mass range the accurate treatment of photoionisation effects is most relevant, particularly with respect to atmospheric mass loss and the parameters relevant for interpreting observations, such as temperature and ion fraction.
Methods. We developed the Cloudy e Hydro Ancora INsieme (CHAIN) model, which combines our 1D hydrodynamic upper atmosphere model with the non-local thermodynamical equilibrium (NLTE) photoionisation and radiative transfer code Cloudy accounting for ionisation, dissociation, detailed atomic level populations, and chemical reactions for all chemical elements up to zinc. The hydro-dynamic code is responsible for describing the outflow, while Cloudy solves the photoionisation and heating of planetary atmospheres. We applied CHAIN to model the upper atmospheres of a range of Neptune-like planets with masses between 1 and 50 M⊕, also varying the orbital parameters.
Results. For the majority of warm and hot Neptunes, we find slower and denser outflows, with lower ion fractions, compared to the predictions of the hydrodynamic model alone. Furthermore, we find significantly different temperature profiles between CHAIN and the hydrodynamic model alone, though the peak values are similar for similar atmospheric compositions. The mass-loss rates predicted by CHAIN are higher for hot strongly irradiated planets and lower for more moderate planets. All differences between the two models are strongly correlated with the amount of high-energy irradiation. Finally, we find that the hydrodynamic effects significantly impact ionisation and heating.
Conclusions. The impact of the precise photoionisation treatment provided by Cloudy strongly depends on the system parameters. This suggests that some of the simplifications typically employed in hydrodynamic modelling might lead to systematic errors when studying planetary atmospheres, even at a population-wide level.
Can the giant planets of the Solar System form via pebble accretion in a smooth protoplanetary disc?
Authors: Lau Tommy Chi Ho , Lee Man Hoi , Brasser Ramon , Matsumura Soko 
Published: January 2024

Context. Prevailing N-body planet formation models typically start with lunar-mass embryos and show a general trend of rapid migration of massive planetary cores to the inner Solar System in the absence of a migration trap. This setup cannot capture the evolution from a planetesimal to embryo, which is crucial to the final architecture of the system.
Aims. We aim to model planet formation with planet migration starting with planetesimals of ~10−6−10−4 M⊕ and reproduce the giant planets of the Solar System.
Methods. We simulated a population of 1000-5000 planetesimals in a smooth protoplanetary disc, which was evolved under the effects of their mutual gravity, pebble accretion, gas accretion, and planet migration, employing the parallelized N-body code SyMBAp.
Results. We find that the dynamical interactions among growing planetesimals are vigorous and can halt pebble accretion for excited bodies. While a set of results without planet migration produces one to two gas giants and one to two ice giants beyond 6 au, massive planetary cores readily move to the inner Solar System once planet migration is in effect.
Conclusions. Dynamical heating is important in a planetesimal disc and the reduced pebble encounter time should be considered in similar models. Planet migration remains a challenge to form cold giant planets in a smooth protoplanetary disc, which suggests an alternative mechanism is required to stop them at wide orbits.
HdC and EHe stars through the prism ofGaiaDR3
Authors: Tisserand P. , Crawford C. L. , Soon J. , Clayton G. C. , Ruiter A. J. , Seitenzahl I. R. 
Published: January 2024

Context. Upon its release theGaiaDR3 catalogue has led to tremendous progress in multiple fields of astronomy by providing the complete astrometric solution for nearly 1.5 billion sources.Aims. We analysed the photometric and astrometric results for Hydrogen-deficient Carbon (HdC), Extreme Helium (EHe), and DYPer type stars to identify any potential biases. This analysis aimed to select stars suitable for kinematic and spatial distribution studies.Methods. We investigated the information obtained from theGaiaimage parameter determination (IPD) process, which was cross-matched withGaialight curves. One main objective was to understand the impact of photometric declines in R Coronae Borealis (RCB) stars onGaiaastrometry.Results. Based on the evidence gathered, we have reached the conclusion that the astrometric fits for numerous RCB stars, including R CrB itself, are not valid due to theGaiapoint spread function (PSF) chromaticity effect in both shape and centroid. The astrometric results of all stars with a significant time-dependent colour variation should be similarly affected. RCB stars might thus be promising sources to correct this effect in futureGaiareleases. Furthermore, after validating theGaiaastrometric results for 92 stars, we observed that the majority of HdC and EHe stars are distributed across the three old stellar structures, the thick disk, the bulge and the halo. However, we have also uncovered evidence indicating that some HdC and EHe stars exhibit orbits characteristic of the thin disk. This is also particularly true for all DYPer type stars under study. Finally, we have produced a list of star memberships for each Galactic substructure, and provided a list of heliocentric radial velocities and associated errors for targets not observed byGaiaDR3.Conclusions. We are beginning to observe a relationship between kinematics, stellar population, and metallicity in RCB and EHe stars. That relation can be explained, within the double degenerate scenario, by the large range in the delay time distribution expected from population synthesis simulations, particularly through the HybCO merger channel.
Optimization of systems of industrial ventilation – case study
Authors: Drăgoescu Răzvan , Cămărășescu Alexandru 
Published: January 2024

Industrial ventilation involves a deep knowledge of fluid dynamics, in the modern computerized version, three-dimensional heat propagation, complex fluid flow, equilibrium state and transient conditions, operating problems, contamination inside or outside the installations, etc.
Industrial buildings generally comprise large spaces with varied sources of damage. The type of sources and their location depend on the technological process in each section. In order to dilute the harms, to ensure the environmental conditions necessary for the protection of the work and the realization of the microclimate required by the production process, through the industrial ventilation installations large air flows are carried.
The design of the ventilation systems in the industrial sections requires a thorough knowledge of the technological process, of the machines and their location, the nature and quantity of the damages, the environmental conditions required from the technological point of view and of the labor protection.. In order to optimize the industrial ventilation systems, an industrial ventilation installation for exhausting and neutralizing VOC emissions was chosen. The optimization of the ventilation installation was possible with the help of the pressure loss balancing methodology.
Aspects Regarding the Certification of Electrical Equipment Used in Potentially Explosive Environments in Accordance with EU Directive 2014/34
Authors: Rad Marcel Daniel , Szido Sorin 
Published: January 2024

EU Directive 2014/34 establishes the standards for the certification of electrical equipment used in potentially explosive atmosphere.
The EU has established standards for the certification of electrical equipment used in potentially explosive atmosphere. EU Directive 2014/34 sets out the requirements for certification and compliance. The directive applies to all electrical equipment to be used in potentially explosive atmosphere. The directive applies to manufacturers of electrical equipment and their authorized representatives. The directive sets out the safety requirements that electrical equipment must meet before it can be certified for use in potentially explosive atmosphere. The directive classifies potentially explosive atmosphere into three categories: Zone 0, Zone 1 and Zone 2. The directive also sets out requirements for marking electrical equipment that has been certified for use in potentially explosive atmosphere.
Certification of electrical equipment involves testing the equipment to ensure that it meets safety requirements. Testing is performed by certified testing laboratories. Testing laboratories are accredited by the relevant national accreditation bodies. The testing laboratories follow the procedures laid down in the directive for testing electrical equipment. Testing includes testing the equipment for electrical safety, mechanical safety and thermal safety. The testing also includes testing the equipment for its ability to prevent ignition of potentially explosive atmospheres.
Explosion risk assessment - an important chapter of the explosion protection document
Authors: Radu Mirela Ancuta , Jurca Adrian Marius 
Published: January 2024

In order to improve the safety and health protection of workers who may be exposed to a potential risk due to explosive atmospheres, in every industrial area where such atmospheres may occur, the employer shall ensure the development and updating of a document called Explosion Protection Document. The main chapter of this document is the Explosion Risk Assessment.
Risk assessment is a complex process that involves identifying the risk, analyzing the risk and estimating the risk, the main purpose of assessing the level of risk being to establish the necessary protection measures to reduce it to acceptable levels.
This paper identifies the factors that may influence the level of risk of explosions in the workplace in order to establish the protection measures required to reduce the risk to acceptable levels.
Explosion risk assessment must be performed by competent persons with knowledge of technical, electrical and mechanical engineering and who understand the general principles of explosion protection.
The specific risks encountered at workplaces in the mines of the Jiu Valley and their correlation with the levels of danger
Authors: Matei Andrada Denisa , Morar Marius Simion , Cioara Cristian Raul 
Published: January 2024

In order to ensure an appropriate level of security and health in underground mining works, it is necessary to apply some methods of diagnosing the situation of the work system/workplace, from the aspect of work security, which involves:

-knowing the risk factors of occupational injury and illness;
-the ranking of risk factors in relation to the potential seriousness of the consequences on the executor;
-identification and ranking of preventive measures to be applied.

The assessment of the risk level is a systematic examination of all aspects of the work process, undertaken in order to eliminate the sources that could cause bodily harm, which constitute the basis for the substantiation of measures to prevent and combat risks. For this reason, all those involved in the work process must be consulted in the risk assessment process.
Specific risk monitoring aims to carry out a pre-accident type assessment of the risk of occupational injury and illness using assessment criteria that are based on quantitative risk assessment.
Pflegebedürftigkeit analysieren – Potential der Daten
aus Pflegebegutachtungen des Medizinischen Dienstes Bayern für Public
Health-Forschung und -Praxis
Authors: Schütz Johanna , Redlich Marie-Christin , Fischer Florian 
Published: January 2024

Zusammenfassung
Hintergrund Ungeachtet der Implikationen des demografischen Wandels
existiert in Deutschland bislang noch keine systematische und vergleichbare
Differenzierung einer Pflegeberichterstattung auf kleinräumiger Ebene,
in welcher die Situation der ambulanten pflegerischen Versorgung abgebildet
wird. Daher ist das Ziel dieses Beitrags, Erkenntnisse der Pflegebegutachtung
des Medizinischen Dienstes Bayern darzustellen und daraus Ableitungen
für eine zukünftige Pflegeberichterstattung zu ziehen.
Methodik Für die Analyse wurden anonymisierte
Pflegeerstbegutachtungen des Medizinischen Dienstes Bayern des Jahres 2019
exemplarisch mittels deskriptiver Methoden ausgewertet. Die Studie beschreibt
die Charakteristika von Personen mit Pflegegradempfehlung, die Verteilung der
Pflegegrade, medizinische Diagnosen sowie Grad der Selbstständigkeit in
den Lebensbereichen.
Ergebnisse Die begutachteten Personen weisen ein Durchschnittsalter von 80
Jahren auf. Zum Zeitpunkt der Erstbegutachtung lebte der größte
Anteil der Personen mit zugewiesenem Pflegegrad in einer ambulanten
Wohnsituation. Pflegegrad (PG) 1 (geringe Beeinträchtigung der
Selbständigkeit oder der Fähigkeiten) erhielten 35,1%
der Versicherten, PG 2 (erhebliche Beeinträchtigungen) 43,1%, PG
3 (schwere Beeinträchtigungen) 16,6%, PG 4 und 5 (schwerste
Beeinträchtigungen) wurden jeweils im niedrigen einstelligen
Prozentbereich bei der Erstbegutachtung vergeben (3,9% bzw.
1,4%). Bei den medizinischen Diagnosen dominierten v. a.
Störung des Ganges und der Mobilität, nicht näher
bezeichnete Demenz, Herzinsuffizienz sowie Senilität. Insbesondere die
Lebensbereiche ‚Mobilität‘ und ‚Gestaltung des
Alltagslebens sowie sozialer Kontakte‘ sind mit Einschränkungen
bei den Pflegebedürftigen verbunden.
Schlussfolgerung Die beim Medizinischen Dienst vorliegenden Daten
können eine hohe Relevanz für Gesundheitsforschung und -politik
einnehmen und eine Grundlage für die Interventionsplanung im
Pflegebereich bieten.
Mikrobielle Belastung der Umgebung während der Anwendung der Hochfrequenz-Jetventilation in der Bronchoskopie
Authors: Luecke Eva , Brunner Juliane , Stegemann-Koniszewski Sabine , Kaasch Achim , Bauer Katja , Geginat Gernot , Hachenberg Thomas , Schilling Thomas , Schwarze Lisa-Lisett , Schreiber Jens 
Published: January 2024

Zusammenfassung
Hintergrund Die Hochfrequenz-Jetventilation (HFJV) wird in der pneumologischen Endoskopie für starre, diagnostische und therapeutische Bronchoskopien genutzt. Unklar ist hierbei, inwieweit durch den ungehinderten Atemgasstrom aus der Lunge des Patienten eine mikrobielle Belastung der Umgebungsluft entsteht.

Material und Methoden Nach Beginn der HFJV (15 min) bei 16 starren Bronchoskopien wurden direkt am distalen Endoskopausgang, auf Untersucherhöhe (40 cm über dem Endoskopausgang), in 2 m Abstand vom Endoskop im Raum sowie am Zuluftauslass des Untersuchungsraums Luftkeimmessungen mit einem RCS-Luftkeimsammler vorgenommen. Anschließend erfolgten die Bestimmung der Anzahl und Art der isolierten Erreger in den Luftproben sowie eine Keimbestimmung in der bronchoalveolären Lavageflüssigkeit (BALF) aus der Patientenlunge.

Ergebnisse Direkt am distalen Ende des Endoskops und auf Untersucherhöhe in 40 cm Entfernung wurde eine erhöhte Keimdichte (136 und 114 KBE/m3) nachgewiesen, die mit zunehmendem Abstand vom Bronchoskop deutlich abnahm (in 2 m Entfernung 98 KBE/m3 und am Zuluftauslass 82 KBE/m3). Die am häufigsten nachgewiesenen Bakterien waren Staphylococcus spp., Micrococcus spp. und Bacillus spp. In der BALF konnten nur in 4 von 16 Proben Erreger kultiviert werden, jedoch wurden dieselben Erreger in der BALF und der Umgebungsluft nachgewiesen.

Schlussfolgerungen Bei der Durchführung einer starren Bronchoskopie, bei der die Patienten mit einem offenen HFJV-System kontrolliert mechanisch ventiliert werden, entsteht eine erhöhte Erregerbelastung der Umgebungsluft und damit eine potenzielle Gefahr für den Untersucher.
Glovebox-assisted magnetic force microscope for studying air-sensitive samples in a cryogen-free magnet
Authors: Zhang Yuchen , Zhao Kesen , Zheng Shaofeng , Wang Jihao , Zhang Jing , Feng Qiyuan , Wang Ze , Gao Jianhua , Hou Yubin , Meng Wenjie , Lu Yalin , Lu Qingyou 
Published: January 2024

Most known two-dimensional magnets exhibit a high sensitivity to air, making direct characterization of their domain textures technically challenging. Herein, we report on the construction and performance of a glovebox-assisted magnetic force microscope (MFM) operating in a cryogen-free magnet, realizing imaging of the intrinsic magnetic structure of water and oxygen-sensitive materials. It features a compact tubular probe for a 50 mm-diameter variable temperature insert installed in a 12 T cryogen-free magnet. A detachable sealing chamber can be electrically connected to the tail of the probe, and its pump port can be opened and closed by a vacuum manipulator located on the top of the probe. This sealing chamber enables sample loading and positioning in the glove box and MFM transfer to the magnet maintained in an inert gas atmosphere (in this case, argon and helium gas). The performance of the MFM is demonstrated by directly imaging the surface (using no buffer layer, such as h-BN) of very air-sensitive van der Waals magnetic material chromium triiodide (CrI3) samples at low temperatures as low as 5 K and high magnetic fields up to 11.9 T. The system’s adaptability permits replacing the MFM unit with a scanning tunneling microscope unit, enabling high-resolution atomic imaging of air-sensitive surface samples.
Cosmology from the vacuum
Authors: Antonini Stefano , Simidzija Petar , Swingle Brian , Van Raamsdonk Mark 
Published: January 2024

Abstract
We argue that standard tools of holography can be used to describe fully non-perturbative microscopic models of cosmology in which a period of accelerated expansion may result from the positive potential energy of time-dependent scalar fields evolving towards a region with negative potential. In these models, the fundamental cosmological constant is negative, and the Universe eventually recollapses in a time-reversal symmetric way. The microscopic description naturally selects a special state for the cosmology. In this framework, physics in the cosmological spacetime is dual to the vacuum physics in a static planar asymptotically AdS Lorentzian wormhole spacetime, in the sense that the background spacetimes and observables are related by analytic continuation. The dual spacetime is weakly curved everywhere, so any cosmological observables can be computed in the dual picture via effective field theory without detailed knowledge of the UV completion or the physics near the big bang. In particular, while inflation may explain the origin of perturbations in the cosmology picture, the perturbations can be deduced from the dual picture without any knowledge of the inflationary potential.