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Kinetochore mutations and histone phosphorylation pattern changes accompany holo- and macro-monocentromere evolution
No full textCentromeres are essential for kinetochore assembly and spindle attachment. While chromosomes of most species are monocentric with a single centromere, a minority exhibit holocentricity, with a centromere along the chromatid length. Sporadic emergence of holocentricity suggests multiple independent transitions. To explore this, we compare the centromere and (epi)genome organization of two sister genera with contrasting centromere types: Chamaelirium luteum with large macro-monocentromeres and Chionographis japonica with holocentromeres. Both exhibit chromosome-wide histone phosphorylation patterns distinct from typical monocentric species. Kinetochore analysis reveals similar chimeric Borealin in both species, with additional KNL2 loss and NSL1 chimerism in Cha. luteum. The broad-scale synteny between both genomes supports de novo holocentromere formation in Chi. japonica. Despite sharing features with both centromere types, macro-monocentromeres do not represent a direct link between mono- and holocentromeres. We propose a model for the divergent evolution involving kinetochore gene mutations, altered histone phosphorylation patterns, and centromeric satellite DNA amplification
Application of the homogeneous relaxation model for flash boiling under sub-atmospheric pressures
No full textFlashing two-phase flows under sub-atmospheric outlet conditions in a converging–diverging nozzle are investigated using the Homogeneous Relaxation Model (HRM) within a two-phase mixture flow framework. The main objectives of this study are to conduct an in-depth investigation of low-temperature, low-pressure flash evaporation, which is essential in flash-based wastewater purification and power generation systems that utilize low-grade waste heat as an energy source, and to support the improvement of a proof-of-concept experimental setup currently being established in our laboratory through the findings of this study.
The numerical results demonstrate that the mathematical model accurately reproduces pressure and void fraction distributions reported in the literature. It also captures key flashing features—including pressure undershoots, vapor generation delays, and pressure recovery—through the relaxation-time formulation. The results indicate that flashing flow in a converging–diverging nozzle is characterized by a sharp pressure drop near the throat, followed by rapid vapor generation and partial pressure recovery in the diverging section. This behaviour is primarily governed by nozzle geometry and the large disparity in specific volumes between the liquid and vapor phases. Vapor generation increases markedly at higher inlet pressures and temperatures, driven by the greater availability of superheat energy. The simulations further reveal that the mass flow rate is highly sensitive to inlet conditions: elevated inlet temperatures intensify vapor generation and consequently reduce mass flow rate, whereas achieving both high vapor production and high mass flow rates requires sufficiently high inlet pressures. The model also predicts shorter flash-delay distances at higher pressures, indicating an earlier onset of phase change, while longer delays occur at elevated temperatures due to increased metastability. Additionally, pressure undershoots become more pronounced with higher inlet temperatures, whereas their dependence on inlet pressure is negligible. It is found that, under fixed inlet conditions, lower sub-atmospheric back pressures enhance steam generation and promote pressure recovery after the nozzle throat, while simultaneously reducing the mass flow rate and the magnitude of pressure undershoots
Coupling of SPH and Volume-of-Fluid for multiphase flow
No full textA new methodology for coupling Smoothed Particle Hydrodynamics (SPH) with a Finite Volume (FV) solver for multiphase flow is presented. The approach follows a patched-domain strategy in which the two domains are disjointly separated by a discrete coupled boundary. Consequently, the coupled SPH–FV method is able to benefit from both methods’ strengths in their respective domains. The SPH solver employs a custom scheme, whereas a preexisting FV solver employing a Volume-of-Fluid (VoF) multiphase representation is adapted with minor modifications.
Key features of the coupling include the determination of the volume fraction at the coupled boundary, the preservation of the fluid interface, and surface tension modeling in the vicinity of the coupled boundary. The method is validated against a series of benchmark cases, showing very good agreement. To our knowledge, this is the first coupled SPH–FV method that allows interface advection across the coupled boundary for multiphase flow with surface tension
Co-evaporated perovskites and incorporation into tandem solar cells
No full textDa der vom Menschen verursachte Klimawandel allmählich die sozioökonomische Politik bestimmt und vorausschauende Nationen angesichts des steigenden Energieverbrauchs Netto-Null-Emissionen anstreben, ist Solarenergie die billigste Quelle für erneuerbare Energie. Unter den Solartechnologien der nächsten Generation sind Perowskit-Solarzellen (PSC) ein aussichtsreicher Kandidat um den wachsenden Energiebedarf zu decken. Sie versprechen hohe Wirkungsgrade bei der Energieumwandlung, niedrige Materialkosten und das Potenzial, sich mit bestehenden Technologien zu Tandemsolarzellen zu kombinieren. Gasphasen-Perowskite sind besonders kompatibel mit den derzeitigen industriellen Fertigungstechnologien. Allerdings müssen grundlegende Herausforderungen bewältigt werden, damit ko-verdampfte Gasphasen-Perowskite für die Kommerzialisierung in Frage kommen. Erstens gibt es ein Wirkungsgrad-Defizit zwischen typischen ko-verdampften und lösungsgefertigten Perowskiten welches sich im Großen und Ganzen durch folgende Faktoren erklären lässt: minderwertige Materialeigenschaften, ein Mangel an kompatiblen Passivierungsmitteln und minderwertige vakuum-prozessierte Löchertransportschichten (HTLs) in der Gasphase. Darüber hinaus bedeutet das substratabhängige Wachstum von ko-verdampften Perowskiten, dass jede neue Entwicklung von Dampfphasen-HTLs auch die resultierende Perowskit/HTL-Grenzfläche verstehen muss. Schließlich ist das Verständnis der vergleichbaren optischen Eigenschaften von semitransparenten (ST) PSCs noch begrenzt, was für Tandemarchitekturen von großer Bedeutung ist. Die zweite große Herausforderung ist die Geschwindigkeit der Abscheidung. Die Ko-Verdampfung ist ein relativ langsamer Prozess mit Abscheidungsraten, die um Größenordnungen unter dem liegen, was für die Kommerzialisierung erforderlich ist. Dies ist zum Teil auf das mangelnde Verständnis des Sublimationsverhaltens organischer Kationen bei hohen Abscheidungsraten zurückzuführen. Diese Arbeit zielt darauf ab, diese Herausforderungen durch die Entwicklung effizienter ko-verdampfter PSCs zu bewältigen, einschließlich ihrer Einbindung in monolithische und mechanisch gestapelte Tandemarchitekturen, um ihre Machbarkeit zu demonstrieren.
Erstens trägt diese Arbeit durch die systematische Optimierung der optischen Eigenschaften von ST-PSC zur Entwicklung von vierpoligen Perowskit/CIGS-Tandembauelementen bei. Vorder- und rückseitig transparente leitfähige Oxide und antireflektierende Beschichtungen werden untersucht, um die NIR-Transmission zu maximieren. Dies wird durch eine Reihe von optischen Simulationen unterstützt, um das zukünftige Potenzial des optischen Managements zu bestimmen. Mit dieser Strategie lassen sich vierpolige Perowskit/CIGS-Tandemsolarzellen mit PCEs von 27,3 % für lösungsprozessierte und 23,8 % für co-verdampfte Perowskit-Absorber erzielen. Die Ergebnisse im Lösungsprozess stellen nahezu einen Weltrekord an Effizienz für 4T-Perowskit/CIGS-Tandemgeräte dar.
Zweitens wird in dieser Arbeit eine Dampfphasenabscheidungsmethode für SAM-HTLs auf Basis selbstorganisierter Monolagen entwickelt. Diese Schichten sind für die Entwicklung von p-i-n-PSCs von entscheidender Bedeutung, wurden bisher jedoch ausschließlich mit lösungsbasierten Methoden abgeschieden. Die Auswirkungen der Verdampfung auf die chemischen Eigenschaften dieser Materialien werden gründlich untersucht um sicherzustellen, dass sie sich während der Abscheidung nicht thermisch zersetzen. Anschließend werden die Grenzflächeneigenschaften zwischen aufgedampften und in Lösung hergestellten SAM-HTLs verglichen, wobei für alle untersuchten Materialien vergleichbare Grenzflächeneigenschaften sowohl mit in Lösung hergestellten als auch mit mitverdampften Perowskit-Absorbern festgestellt wurden. Die Dampfphasenabscheidung erhöht die Flexibilität dieser Materialien erheblich und ist eine inhärent konforme und skalierbare Methode.
Als nächstes werden in dieser Arbeit die Grenzflächenwechselwirkungen untersucht, die zwischen SAM-HTLs, einschließlich aufgedampfter SAM-HTLs, und ko-verdampften Perowskiten auftreten. Aufgrund des substratabhängigen Wachstums von ko-verdampften Perowskiten ist das Verständnis dieser Wechselwirkungen entscheidend für die Entwicklung aller Dampfphasen-PSCs mit SAM-HTLs. Mit Hilfe verschiedener Techniken wird die Form dieser Wechselwirkung als Wasserstoffbrückenbindung zwischen Phosphonsäuren und Grenzflächenhalogeniden bewertet, die sich in erster Linie auf den Einbau organischer Kationen in den Perowskit auswirkt. Darüber hinaus werden die Auswirkungen dieser Wechselwirkung auf das Wachstum des Perowskits und die photovoltaischen Eigenschaften untersucht. Diese Wechselwirkung stellt eine bisher unbekannte Form der Substratwechselwirkung bei ko-verdampften Perowskiten dar und erweitert das Verständnis dieses wichtigen Parameters erheblich.
Schließlich werden in dieser Arbeit die Auswirkungen einer erhöhten Abscheidungsrate auf co-verdampfte Perowskite auf Formamidinium (FA)-Basis untersucht. Die potenzielle Zersetzung des FA-Kations ist für die Erzielung kommerziell nutzbarer Abscheidungsraten von Perowskiten von großer Bedeutung. Wir stellen fest, dass thermische Schwankungen innerhalb des Tiegels zu einer selektiven Zersetzung des Materials führen, der sich bei hohen Raten auf die Eigenschaften der Bauteile auswirkt. Es werden drei Methoden vorgeschlagen und bewertet, um diese Einschränkung zu verringern. Dazu gehören die Verwendung zusätzlicher organischer Quellen, die Vorkonditionierung des organischen Materials und das Design des Tiegels. Darüber hinaus werden durch den Einbau von Perowskiten mit niedriger und hoher Abscheidungsrate in monolithische Tandems weitere potenzielle Probleme mit hohen Abscheidungsraten untersucht. Diese Arbeit liefert wichtige Erkenntnisse darüber, was erforderlich ist, um die Abscheidungsraten von ko-verdampften Perowskiten sinnvoll zu erhöhen
Multi-Objective Reinforcement Learning with Shielding for Control and Safety in Power Grids
No full textTraditional model-based methods relying on precise modeling are sensitive to errors and rapidly changing conditions, causing unstable control. Furthermore, real-world problems often involve conflicting objectives, requiring multi-objective reinforcement learning (MORL) in order to facilitate adaptability. However, MORL and single-objective RL (SORL) research often address these challenges separately due to the lack of a unified framework. To bridge this gap, we present eGridLVGym, an open-source collection of two test environments for managing low-voltage grids. The first environment models a household with rooftop photovoltaics, battery storage, electric vehicle charging, and a heat pump. The second extends this to a feeder grid with seven points of common coupling, representing diverse portfolios of distributed energy resources. These environments support system-wide flexibility dispatch while ensuring safety through soft and hard constraints that penalize or restrict unsafe actions. We evaluate eight state-of-the-art SORL algorithms (A2C, DDPG, PPO, SAC, TD3, Recurrent PPO, TQC, and TRPO), a grid code shielding approach, and the MORL algorithm CAPQL. Our results demonstrate that the best SORL algorithm reduces transformer overload from 93% to 75% and cuts economic costs to 122%, while the default-weighted MORL outperforms the rule-based controller by 77% in economic cost
Data-driven artificial intelligence applications for tyre-road-noise prediction and road condition monitoring: A review and future directions
No full textNoise is an important environmental issue that affects quality of life and health, especially in urban areas. With the widespread adoption of electric vehicles, engine noise inside the car has decreased significantly, making tyreroad noise the main noise source, which also accounts for a large proportion of traffic noise. The powerful tool that is artificial intelligence (AI) has emerged in recent years for noise management and monitoring. AI-based systems can classify noise sources, create noise maps and develop control strategies. As a result, some studies
have focused on improving road, vehicle mechanics, and tyre textures and improving the sound quality of tyreroad noise. However, research specifically on tyre-road noise prediction is quite limited. Studies in the literature have generally focused on predicting road damage, surface quality and weather conditions, with less emphasis on tyre-road noise prediction. Many of these studies estimate tyre-road noise by modeling. However, it is not possible for modeling to capture real environment data. Therefore, more data-based studies on tyre-road noise
optimization, monitoring and prediction are needed in this area. This paper focuses on data-based studies and is a discussion of techniques such as data acquisition, feature extraction and selection, and artificial intelligence
algorithms that have been or could be used in this area. Data-driven artificial intelligence methods, such as deep learning, are highlighted for their significant potential in tyre-road noise monitoring and prediction. As a result, future research is expected to focus more on deep learning applications, opening new perspectives for further development in this field.
The Berry curvature in the framework of current density functional theory for molecules in external magnetic fields
No full textIn this work, we investigate the quantum geometry framework for molecules in external magnetic fields. For electronic ground states, the linear response formalism through which the quantum geometric tensor can be computed was described by Culpitt et al. [J. Chem. Phys. 156, 044121 (2022)], and this work expands their framework to current density functional theory. We show that for nuclear displacements, the Fubini–Study metric can be connected to the diagonal Born–Oppenheimer correction. Furthermore, we examine the effects of external magnetic fields on the molecular Berry curvature. For selected systems, we investigate how different density functional approximations compare to both full configuration interaction and Hartree–Fock theory. Finally, the convergence of the Berry curvature with respect to the numerical grid is estimated for different functionals, highlighting some known deficiencies of modern density functional approximations
Environmental dynamics recorded at Dupljaja loess section (southeastern Carpathian Basin, northern Serbia)
No full textThe Dupljaja loess-palaeosol sequence in the southeasternmost sector of the Banat Loess Plateau, Serbia, is of significant palaeoenvironmental importance. Situated within the southeastern Carpathian (Middle Danube) Basin, it provides valuable insights into the climatic evolution during the last glacial period and role of the southeastern Carpathians as a potential migration corridor for early humans across Europe.
The stratigraphic pattern of the Dupljaja section mirrors analogous profiles in the northern Serbia, based on luminescence dating and the correlation of magnetic record with the Marine Oxygen Isotope stratigraphy. Importantly, the grain size data from the section provides crucial insight into regional dust accumulation dynamics. Three distinct depositional modes are identified: finer modes were dominant in the Holocene and late last glacial intervals, whereas a coarser mode prevailed in the Marine Isotope Stage (MIS) 3 interval. To better understand these variations in grain size records, we have undertaken a comparative analysis of regional palaeoclimate model data between the Last Glacial Maximum (LGM) and typical Greenland Stadial and Interstadial conditions. Model results indicate slightly drier regional climate conditions during the LGM than during stadial, while granulometry data suggests that the deposition of coarser loess during MIS 3 is related to drier conditions in the local source area (the Danube River alluvial plain), resulting in coarser material available for aeolian action. We propose that the drier hydroclimate of the Danube Palaeolithic corridor associated with steppic environmental conditions between ∼53–37 ka may have facilitated migrations of anatomically modern humans from Asia into Europe
Nucleation-Mediated Aluminum Deposition/Stripping for Long-Life Molten Salt Aluminum Batteries
No full textMolten salt aluminum batteries (MSABs) hold significant promise for grid-scale energy storage due to the low cost and high capacity of the aluminum anode. However, an aluminum dendrite stemming from nonuniform electrodeposition leads to safety and stability issues. Here, we describe a membrane electrode with predeposited aluminum metal featuring surface-mediated nucleation and growth behavior for operation in alkali chloroaluminate melt electrolytes. The introduction of TiN, as aluminophilic sites, facilitates the initial growth of aluminum on TiN by forming Al–N bonding, thereby enabling uniform aluminum nucleation and mediated growth along the TiN/C fiber, resulting in reversible and dendrite-free aluminum plating/stripping. The TiN/C@Al electrode enables symmetric cells to maintain stable cycling for over 850 h (10.0 mA cm; 5.0 mA h cm) and shows high rate performance at up to 30.0 mA cm. The Al-graphite cell using a TiN/C@Al anode demonstrates long-term stability over 7000 cycles at 2.0 A g and enhanced rate capability with 72.2 mA h g even at 5.0 A g. To validate practical scalability, we designed an Ah-level TiN/C@Al-based molten salt Al-graphite pouch cell. This approach offers a scalable pathway for overcoming the limitations of state-of-the-art anodes in MSABs, enabling high-performance and cost-effective energy storage solutions
