bluuebunny/crossref_metadata_2025 huggingface dataset:
A Nonpulsatile Artificial Heart
Authors: Rafferty Edson H. , Kletschka Harold D. , Olsen Douglas A.
Published: October 2023

The concept of a nonpulsatile artificial heart is discussed. The approach used in this investigation embodies the principle of a constrained force vortex to propel the blood. This novel approach eliminates the need for the direct contact of blood with impellers and also alleviates the constrictive and mechanical forces on blood cells resulting from high levels of shear and turbulence as well as direct impaction. By eliminating the direct contact of blood with these mechanical forces and with the use of atraumatic and nonthrombogenic low temperature isotropic carbon as the material of construction, a largely atraumatic pump is made possible. The use of force vortices enables the investigators to retain the high efficiency of a centrifugal impeller pump without encountering the traumatic effects of direct impeller contact. The result is a high efficient, atraumatic, nonpulsatile blood pump. The possible effects of nonpulsatile flow in the body are reviewed. Pump optimization is discussed. Finally, implantation of the artificial heart pump into animals on an experimental basis is discussed briefly.
Flow Chamber Analyses in Cardiovascular Research: Impact of Platelets and the Intercellular Crosstalk with Endothelial Cells, Leukocytes, and Red Blood Cells
Authors: Krott Kim Jürgen , Feige Tobias , Elvers Margitta
Published: October 2023

Platelets are main drivers of thrombus formation. Besides platelet aggregate formation, platelets interact with different blood cells such as red blood and white blood cells (RBCs, WBCs) and endothelial cells (ECs), to promote thrombus formation and inflammation. In the past, the role of different proteins in platelet adhesion, activation, and aggregate formation has been analyzed using platelets/mice with a genetic loss of a certain protein. These knock-out mouse models have been investigated for changes in experimental arterial thrombosis or hemostasis. In this review, we focused on the Maastricht flow chamber, which is a very elegant tool to analyze thrombus formation under flow using whole blood or different blood cell components of genetically modified mice. Besides, the interaction of platelets with RBCs, WBCs, and ECs under flow conditions has been evaluated with regard to thrombus formation and platelet-mediated inflammation. Importantly, alterations in thrombus formation as emerged in the flow chamber frequently reflect arterial thrombosis in different mouse models. Thus, the results of flow chamber experiments in vitro are excellent indicators for differences in arterial thrombosis in vivo. Taken together, the Maastricht flow chamber can be used to (1) determine the severity of platelet alterations in different knock-out mice; (2) analyze differences in platelet adhesion, aggregation, and activation; (3) investigate collagen and non–collagen-dependent alterations of thrombus formation; and (4) highlight differences in the interaction of platelets with different blood/ECs. Thus, this experimental approach is a useful tool to increase our understanding of signaling mechanisms that drive arterial thrombosis and hemostasis.
Karzinom, Tuberkulose, atypische Pneumonie – oder vielleicht pulmonale Tularämie? Zwei Fallberichte
Authors: Kimmich Martin , Jakob Maja
Published: October 2023

Tularämie ist eine seltene aber in ländlichen Gebieten ganz Deutschlands endemische Zoonose. Ihre Manifestation bei inhalativem Infektionsweg ruft Erkrankungsbilder hervor, die zunächst an andere atypische Pneumonien, pulmonale Neoplasien oder Tuberkulose denken lassen. Wir stellen zwei für die pulmonale Manifestation typische Erkrankungsfälle vor.
Interprofessionelle Weaning-Boards und Weaning-Konsile für Langzeitbeatmungspatient*innen: Eine qualitative Studie zum wahrgenommenen Potenzial für die Patientenversorgung
Authors: Keller Sabrina , Forstner Johanna , Weis Aline , Biehler Elena , Trudzinski Franziska , Michels Julia , Neetz Benjamin , Herth Felix , Schneider Armin , Ghiani Alessandro , Szecsenyi Joachim , Wensing Michel , Poß-Doering Regina
Published: October 2023

Hintergrund Das Projekt PRiVENT hat sich zum Ziel gesetzt, die Versorgung von invasiv beatmeten Patient*innen zu verbessern und die Anzahl der außerklinischer Langzeitbeatmungspatient*innen zu reduzieren. PRiVENT bietet Intensivstationen die Möglichkeit, sich in interprofessionellen Weaning-Boards und Weaning-Konsilen mit Expert*innen aus spezialisierten Weaning-Zentren auszutauschen und das volle Weaning-Potenzial der Patient*innen auszuschöpfen. Im Rahmen der begleitenden Prozessevaluation werden die PRiVENT-Interventionskomponenten auf Nachhaltigkeit, Skalierbarkeit und Wirksamkeit untersucht sowie die interprofessionelle Zusammenarbeit zwischen Intensivstationen und den zuständigen Weaning-Zentren untersucht, um Potenziale für die Versorgung von invasiv betreuten Patient*innen identifizieren zu können.

Methode In einer qualitativen Querschnittsstudie wurden semistrukturierte, problemorientierte Interviews mit Leistungserbringenden teilnehmender Intensivstationen durchgeführt. Die Daten wurden digital aufgezeichnet, pseudonymisiert und verbatim transkribiert. Die Datenanalyse erfolgte in Anlehnung an die Thematic Analysis nach Brown und Clarke und dem Consolidated Framework for Implementation Research. Zur Organisation der Daten wurde die Software MAXQDA 2020 verwendet.

Ergebnisse Es wurden 14 Interviews mit den Leistungserbringenden der Intensivstationen geführt. Als positiv wahrgenommene Potenziale der Weaning-Boards und Weaning-Konsile wurden die frühzeitige Verlegung von Patient*innen in ein Weaning-Zentrum sowie die Integration von pulmologischem Fachwissen in die Routineversorgung identifiziert. Insbesondere bei schwerkranken, multimorbiden an COVID-19 erkrankten Patient*innen wurde die Expertise der Weaning-Zentren als hilfreich angesehen. Aufgrund der hohen Arbeitsbelastung konnte das Pflegepersonal nicht an den Weaning-Boards und Weaning-Konsilen teilnehmen.

Schlussfolgerung Die Interprofessionelle Zusammenarbeit zwischen Weaning-Zentren und Intensivstationen in Weaning-Boards und Weaning-Konsilen kann die Versorgung invasiv beatmeter Patient*innen verbessern. Strategien zur Förderung des Einbezugs von Pflegefachkräften sollten diskutiert und erarbeitet werden.
Zusammen unschlagbar: Als Physiotherapeutin bei den Special Olympics World Games
Authors: Jasko Annika
Published: October 2023

Vom 17. bis 25. Juni 2023 fanden in Berlin – und damit erstmalig in Deutschland – die Special Olympics World Games unter dem Motto #ZusammenUnschlagbar statt. Als Gastgeber stellte Special Olympics Deutschland die größte Delegation bei den Weltspielen. Annika Jasko ist VPT-Mitglied und hat als Physiotherapeutin vor Ort die deutschen Athletinnen und Athleten mit betreut. Im Interview gibt sie uns einen spannenden Einblick in die Arbeit mit Hochleistungssportler*innen im Wettkampfmodus.
Exploring the employment motivation, job satisfaction and dissatisfaction of university English instructors in public institutions: a Chinese case study analysis
Authors: Morris Gareth , Mo Junhua
Published: October 2023

This study considers the important areas of language teacher employment motivation, job satisfaction and dissatisfaction in state universities in China. This is an area in which there is a distinct lack of research studies. Through an exploratory case study analysis, and depth enlightening interviews, this paper considers the experiences of two outwardly successful doctorate status educators, examining their early career motives and subsequent employment satisfaction and dissatisfaction. It finds that these English instructors were driven by a diverse range of extrinsic motives to work in the Chinese public university sector. They were largely satisfied with their jobs, but they also reported dissatisfaction in certain areas. For example, they appreciated the teaching loads and respect afforded to university teachers, but harboured worries about their longer-term professional development. The study also reveals the different treatment and concerns experienced by home and expatriate university English teachers working in China. There are implications for a wide range of important pedagogic and professional areas. These range from teacher wellbeing and mental health to development and training, career management and leadership practice. On a more macro level still, there are also potential implications for institutional human resource governance.
Phase-change in topological chiral phononic crystal for directional coupling switch
Authors: Xi Feng , Tang Yuxia , Hu Li
Published: October 2023

Recently, acoustic valley Hall topological insulators have become a cutting-edge area of acoustic physics, where the topological phase transition in phononic crystals shows the presence of band inversion through the Dirac point in the momentum space. We developed a 2D hexagonal lattice chiral phononic crystal using reconfigurable construction by extending one side of the original rectangular rods. When the variation of the side length was from left to right, the topological phase transition is triggered by reopening the Dirac degeneracies beyond high-symmetry points in the first Brillouin zone. We numerically showed valley edge state’s propagation through the interface bent toward distinct chiral topological phononic crystals. Moreover, we assembled 2 × 2 cross-waveguides with a defect cavity based on double heterostructure interfaces. The simulated results verify that the phase change is achieved by the directional coupling switching. This research possibly paves the way for exploiting valley edge states to design the complex acoustic waveguide.
Determination of the ground and excited state dipole moments of ferulic and sinapic acids by solvatochromic effects and density function theory method
Authors: Sherefedin Umer , Belay Abebe , Kebede Alemu , Asemare Semahegn , Woldegiorges Kinfe , Kumela Alemayehu Getahun , Gudishe Kusse
Published: October 2023

Ferulic acid (FA) and sinapic acid (SA) are groups of phenolic acids that belong to the class of hydroxycinnamic acid. Due to their molecular structure and functional groups, these compounds exhibit a wide range of biological activities. In this research, we have determined the dipole moments of these compounds in gas and solvent phases using spectroscopic and computational methods. The change in the dipole moments of FA and SA was calculated by Bakhshiev’s, Kawski–Chamma–Viallet’s, Lippert–Mataga’s, and microscopic solvent polarity functions. The results show that the change in the dipole moment calculated using Lippert–Mataga’s method is higher than that using other methods. This is due to the fact that this method ignores the specific interactions of the solute and solvent as well as the polarizability of the solute molecule. Similarly, the ground and excited-state dipole moments were determined by theoretical quantum chemical calculations using density functional theory (DFT); the results are found to be similar to the experimental ones. In both approaches, the excited dipole moment is greater than the ground state, indicating a significant redistribution of electron densities and being more sensitive to the solvent in the excited state for both molecules. The HOMO-LUMO energy bandgaps calculated in the gas phase for FA and SA are 4.001 and 4.055 eV, respectively. In addition, electron charge density maps, UV–Vis absorption spectra, and oscillator strengths were calculated using the DFT method to obtain general information about the compounds.
Doping engineering of ZnO electron transporting layer for high performance CsPbI2Br inorganic perovskite solar cells
Authors: Li Yao , Liu Ning , Xu Zuxiong , Xu Zelin , Pan Yi , Zhang Jing , Huang Like , Hu Ziyang , Zhu Yuejin , Liu Xiaohui
Published: October 2023

An inorganic CsPbI2Br perovskite has garnered significant interest due to its outstanding photoelectrical properties in recent years. However, CsPbI2Br-based perovskite solar cells (PSCs) generally suffer from large energy loss, hindering their further development. Herein, we proposed a facile and effective approach to dope the ZnO electron transporting layer (ETL) with alkaline earth metal ions to boost the photovoltaic performance of CsPbI2Br PSCs. Particularly, the ZnO ETL doped with Ca2+ can simultaneously ameliorate electron transport, energy level alignment, and the quality of the upper CsPbI2Br film, thus resulting in faster charge extraction and suppressed charge recombination. Consequently, the ZnO:Ca-based PSC achieves a champion power conversion efficiency (PCE) of 16.39% with an excellent VOC of 1.292 V, while the control ZnO-based PSC just exhibits an inferior PCE of 14.22% with a VOC of 1.178 V. Furthermore, the ZnO:Ca-based devices also present considerable enhancements in device stability without encapsulation. Our work offers a promising strategy to mitigate the energy loss toward efficient and stable PSCs.
Electrically driven nanoantenna metasurface for coherent thermal emission
Authors: Jing Lin , Liu Xiu , Salihoglu Hakan , Luo Xiao , Yun Hyeong Seok , Wang Zexiao , Shen Sheng
Published: October 2023

Nanoantennas and their arrays (metasurfaces) provide a versatile platform for controlling the coherence of thermal emission. Conventional designs rely on global heating, which impedes emission efficiency and on-chip integration. In this work, we propose an electrically driven metasurface composed of a Yagi-Uda nanoantenna array interconnected by S-shaped electrode wires, which enables the concurrent manipulation of thermal emission spectrally and directionally. A direct simulation approach based on the Wiener-chaos expansion method is employed for quantitative analysis. Our metasurface device exhibits a narrowband emission with high directivity, which is one order higher than that of a single nanorod antenna case. The modeling framework established in this work opens a promising route for realizing coherent mid-infrared emission by metasurfaces.
Design, manufacturing, evaluation, and performance of a 3D-printed, custom-made nozzle for laser wakefield acceleration experiments
Authors: Andrianaki G. , Grigoriadis A. , Skoulakis A. , Tazes I. , Mancelli D. , Fitilis I. , Dimitriou V. , Benis E. P. , Papadogiannis N. A. , Tatarakis M. , Nikolos I. K.
Published: October 2023

Laser WakeField Acceleration (LWFA) is extensively used as a high-energy electron source, with electrons achieving energies up to the GeV level. The produced electron beam characteristics depend strongly on the gas density profile. When the gaseous target is a gas jet, the gas density profile is affected by parameters, such as the nozzle geometry, the gas used, and the backing pressure applied to the gas valve. An electron source based on the LWFA mechanism has recently been developed at the Institute of Plasma Physics and Lasers. To improve controllability over the electron source, we developed a set of 3D-printed nozzles suitable for creating different gas density profiles according to the experimental necessities. Here, we present a study of the design, manufacturing, evaluation, and performance of a 3D-printed nozzle intended for LWFA experiments.
Compressibility effects on the flow past a T106A low-pressure turbine cascade
Authors: Sengupta Aditi , Sundaram Prasannabalaji
Published: October 2023

The present numerical investigation delves into the intricate interplay between Mach number (Ms), flow characteristics, and vorticity dynamics within a T106A low-pressure turbine (LPT) blade passage. The two-dimensional (2D) compressible Navier–Stokes equations are solved using a high-accuracy, dispersion relation preserving methodology, which is validated against benchmark direct numerical simulations. Four Ms ranging from 0.15 to 0.30 are computed in order to display the intricate response of compressibility on the separation-induced transition process. The emergence and evolution of unsteady separation bubbles along the suction surface of the T106A blade are explored, revealing a growing trend with Ms. The time-averaged boundary layer parameters evaluated along the suction surface display a delayed separation with a smaller streamwise extent with increasing Ms. However, an overall increase in the blade profile loss and a decrease in turbulent mixing are observed with increasing Ms, suggesting a detrimental effect on LPT performance. Applying the compressible enstrophy transport equation (CETE) to the flow in a T106A blade passage reveals that while a linear relationship exists between Ms and certain CETE budget terms, other terms have a nuanced dependency, which paves the way for future investigations into the role of compressibility on enstrophy dynamics.
Modeling of the spray-induced wall stress acting on the ignition assistance device
Authors: Kim Sayop , Torelli Roberto , Oruganti Surya Kaundinya , Ryu Je Ir , Lee Tonghun , Kim Kenneth S. , Kweon Chol-Bum M.
Published: October 2023

This research introduces a novel wall-stress model called the Spray-Induced Wall Stress (SIWS) model, which considers the effects of spray-wall impingement and the resulting formation of wall stress within the Lagrangian spray modeling framework. The primary objective of this paper is to provide a mathematical description of the fundamental physics underlying the model. Subsequently, the proposed model is validated using existing experimental data. The remainder of the study focuses on the practical application of the model to an ignition assistance device. Specifically, this device is installed in a compression ignition engine and designed to enhance ignition in aviation-fueled high-altitude aircraft propulsion systems. The research sheds light on the mechanical impulse caused by the high-speed impact of the spray jet, leading to the accumulation of mechanical stress on the rigid body of the ignition assistance device. Previous studies on fluid–structure interaction have only considered the interaction between the gas phase and the solid wall. However, the SIWS model incorporates the additional impact of the impinging liquid spray jet. Consequently, the simulated stress distribution on the ignition assistance device can be estimated by considering both the gas-phase-induced term and the spray-induced term simultaneously.
Quadratic scaling bosonic path integral molecular dynamics
Authors: Feldman Yotam M. Y. , Hirshberg Barak
Published: October 2023

Bosonic exchange symmetry leads to fascinating quantum phenomena, from exciton condensation in quantum materials to the superfluidity of liquid 4He. Unfortunately, path integral molecular dynamics (PIMD) simulations of bosons are computationally prohibitive beyond ∼100 particles, due to a cubic scaling with the system size. We present an algorithm that reduces the complexity from cubic to quadratic, allowing the first simulations of thousands of bosons using PIMD. Our method is orders of magnitude faster, with a speedup that scales linearly with the number of particles and the number of imaginary time slices (beads). Simulations that would have otherwise taken decades can now be done in days. In practice, the new algorithm eliminates most of the added computational cost of including bosonic exchange effects, making them almost as accessible as PIMD simulations of distinguishable particles.
A polygenic explanation for Haldane’s rule in butterflies
Authors: Xiong Tianzhu , Tarikere Shreeharsha , Rosser Neil , Li Xueyan , Yago Masaya , Mallet James
Published: October 2023

Two robust rules have been discovered about animal hybrids: Heterogametic hybrids are more unfit (Haldane’s rule), and sex chromosomes are disproportionately involved in hybrid incompatibility (the large-X/Z effect). The exact mechanisms causing these rules in female heterogametic taxa such as butterflies are unknown but are suggested by theory to involve dominance on the sex chromosome. We investigate hybrid incompatibilities adhering to both rules in
Papilio
and
Heliconius
butterflies and show that dominance theory cannot explain our data. Instead, many defects coincide with unbalanced multilocus introgression between the Z chromosome and all autosomes. Our polygenic explanation predicts both rules because the imbalance is likely greater in heterogametic females, and the proportion of introgressed ancestry is more variable on the Z chromosome. We also show that mapping traits polygenic on a single chromosome in backcrosses can generate spurious large-effect QTLs. This mirage is caused by statistical linkage among polygenes that inflates estimated effect sizes. By controlling for statistical linkage, most incompatibility QTLs in our hybrid crosses are consistent with a polygenic basis. Since the two genera are very distantly related, polygenic hybrid incompatibilities are likely common in butterflies.
First-order quantum phase transition in the hybrid metal–Mott insulator transition metal dichalcogenide 4Hb-TaS
2
Authors: Kumar Nayak Abhay , Steinbok Aviram , Roet Yotam , Koo Jahyun , Feldman Irena , Almoalem Avior , Kanigel Amit , Yan Binghai , Rosch Achim , Avraham Nurit , Beidenkopf Haim
Published: October 2023

Coupling together distinct correlated and topologically nontrivial electronic phases of matter can potentially induce novel electronic orders and phase transitions among them. Transition metal dichalcogenide compounds serve as a bedrock for exploration of such hybrid systems. They host a variety of exotic electronic phases, and their Van der Waals nature enables to admix them, either by exfoliation and stacking or by stoichiometric growth, and thereby induce novel correlated complexes. Here, we investigate the compound 4Hb-TaS
2
that interleaves the Mott-insulating state of 1T-TaS
2
and the putative spin liquid it hosts together with the metallic state of 2H-TaS
2
and the low-temperature superconducting phase it harbors using scanning tunneling spectroscopy. We reveal a thermodynamic phase diagram that hosts a first-order quantum phase transition between a correlated Kondo-like cluster state and a depleted flat band state. We demonstrate that this intrinsic transition can be induced by an electric field and temperature as well as by manipulation of the interlayer coupling with the probe tip, hence allowing to reversibly toggle between the Kondo-like cluster and the depleted flat band states. The phase transition is manifested by a discontinuous change of the complete electronic spectrum accompanied by hysteresis and low-frequency noise. We find that the shape of the transition line in the phase diagram is determined by the local compressibility and the entropy of the two electronic states. Our findings set such heterogeneous structures as an exciting platform for systematic investigation and manipulation of Mott–metal transitions and strongly correlated phases and quantum phase transitions therein.
Cereblon influences the timing of muscle differentiation in
Ciona
tadpoles
Authors: Long Juanjuan , Mariossi Andrea , Cao Chen , Mo Zhongying , Thompson Joel W. , Levine Michael S. , Lemaire Laurence A.
Published: October 2023

Thalidomide has a dark history as a teratogen, but in recent years, its derivates have been shown to function as potent chemotherapeutic agents. These drugs bind cereblon (CRBN), the substrate receptor of an E3 ubiquitin ligase complex, and modify its degradation targets. Despite these insights, remarkably little is known about the normal function of cereblon in development. Here, we employ
Ciona
, a simple invertebrate chordate, to identify endogenous Crbn targets. In
Ciona, Crbn
is specifically expressed in developing muscles during tail elongation before they acquire contractile activity.
Crbn
expression is activated by Mrf, the ortholog of MYOD1, a transcription factor important for muscle differentiation. CRISPR/Cas9-mediated mutations of
Crbn
lead to precocious onset of muscle contractions. By contrast, overexpression of
Crbn
delays contractions and is associated with decreased expression of contractile protein genes such as troponin. This reduction is possibly due to reduced Mrf protein levels without altering
Mrf
mRNA levels. Our findings suggest that Mrf and Crbn form a negative feedback loop to control the precision of muscle differentiation during tail elongation.
From data to theory
Authors: Janda Laura A. , Endresen Anna , Zhukova Valentina , Mordashova Daria , Rakhilina Ekaterina
Published: October 2023

The semantic classification of over 2,200 constructions in the Russian Constructicon has emerged objectively from
empirical analysis. The resulting semantic classification comports with and goes beyond frame semantics, revealing complex
patterns of related constructions verified against corpus data and by a panel of native speakers. Our model of a constructicon can
inform and complement existing approaches with additional findings. We detail our discovery procedure and the semantic
relationships that link constructions. While our methods and findings are based on a single language, they can serve as a basis
for cross-linguistic comparison in the field of Construction Grammar and constructicography research.
Evidential propositions as situational scenarios
Authors: Reda Ghsoon
Published: October 2023

This study examines the interpretation of evidential propositions using insights from theLexical Constructional Model(LCM), including its recent classification of situational scenarios (cognitive models) into three sub-types: descriptive, attitudinal and regulatory. The aim is to show that processing the meaning of an evidential proposition can require profiling parts of all three types of situational scenarios– a process that is activated (at the lexical-constructional, discourse and implicational levels) by such cognitive operations asechoing,contrastandmetonymy. This is consistent with the principles ofRelevanceaccording to which the contextual information required for interpreting the speaker’s explicit/implicit meaning (i.e., explicating/implicating it) is not limited to a particular knowledge type or source (encyclopaedic, socio-cultural, religious and so on). The study, thus, complements work on evidentiality by going beyond its features, markers and behaviour in discourse to focus on the interpretation of evidential propositions in connection with cognitive models and operations.
Determination of Work Function for p- and n-Type 4H-SiC Single Crystals via Scanning Kelvin Probe Force Microscopy
Authors: Li 李 Hui 辉 , Wang 王 Guobin 国宾 , Yang 杨 Jingyu 靖宇 , Zhang 张 Zesheng 泽盛 , Deng 邓 Jun 俊 , Du 杜 Shixuan 世萱
Published: October 2023

Silicon carbide (SiC) is a promising platform for fabricating high-voltage, high-frequency and high-temperature electronic devices such as metal oxide semiconductor field effect transistors in which many junctions or interfaces are involved. The work function (WF) plays an essential role in these devices. However, studies of the effect of conductive type and polar surfaces on the WF of SiC are limited. Here, we report the measurement of WFs of Si- and C-terminated polar surfaces for both p-type and n-type conductive 4H-SiC single crystals by scanning Kelvin probe microscopy (SKPFM). The results show that p-type SiC exhibits a higher WF than n-type SiC. The WF of a C-terminated polar surface is higher than that of a Si-terminated polar surface, which is further confirmed by first-principles calculations. By revealing this long-standing knowledge gap, our work facilitates the fabrication and development of SiC-based electronic devices, which have tremendous potential applications in electric vehicles, photovoltaics, and so on. This work also shows that SKPFM is a good method for identifying polar surfaces of SiC and other polar materials nondestructively, quickly and conveniently.
Black holes and hot shells in the Euclidean path integral approach to quantum gravity
Authors: Lemos José P S , Zaslavskii Oleg B
Published: October 2023

We study a spherical black hole surrounded by a hot self-gravitating thin shell in the canonical ensemble, i.e. a black hole and a hot thin shell inside a heat reservoir acting as a boundary with its area and temperature fixed. To work out the quantum statistical mechanics partition function of this matter-black hole system, from which the thermodynamics of the system follows, we use the Euclidean path integral approach to quantum gravity that identifies the path integral of the gravitational system with the partition function itself. In a semiclassical evaluation of the path integral, one needs to compute the classical action of the system. From the action, one finds the result that the total entropy, given by the sum of black hole and matter entropies, is a function of the gravitational radius of the system alone. So, the black hole inside the shell has no direct influence on the total entropy. One also finds the free energy which is equal to the action times the temperature, the thermodynamic energy, and the temperature stratification along the system. Another important result is that the heat reservoir temperature is composed of a free function of the gravitational radius of the system, which acts as a reduced temperature equation of state, divided by the redshift function at the reservoir. Upon the specification of the reduced temperature, the solutions for the gravitational radii of the system compatible with the boundary data can be found. In addition, it is found that the black hole inside the shell has two possible horizon radii. The first law of thermodynamics is then identified, and it is shown that the first law is satisfied by the system as whole, it is realized by the matter in the hot shell, and it is also applicable to the black hole. The thermodynamic stability analysis is performed through the calculation of the system’s heat capacity. By specifying the available temperature free function as the Hawking temperature equation of state of the gravitational radius of the system, which itself is not a black hole, one finds a remarkable exact mechanical and thermodynamic solution. With the exact solution in hand one establishes that pure black hole spaces, hot shell with a black hole spaces, pure hot shell spaces, and hot flat spaces are phases that cohabit in the ensemble, with some of them acting as thermodynamic mimickers. This exact thermodynamic solution for a black hole with a self-gravitating hot shell is not only of interest in itself, but can also be seen as a model to situations involving black holes interacting with hot gravitons and other hot particles. The study of the high temperature limits for the system also reveals several important aspects.
Multivariate intrinsic wave-characteristic decomposition and its application in gear fault diagnosis
Authors: Zhou Jie , Cheng Junsheng , Yang Yu , Peng Yanfeng
Published: October 2023

In the early stages of gear faults, the background noise in the signal is pronounced, making it challenging to fully assess the health status of equipment based on a single-channel signal. Processing multi-channel signals proves beneficial for extracting fault information comprehensively. Adaptive multivariate signal decomposition methods, such as multivariate empirical mode decomposition (MEMD) and multivariate local characteristic-scale decomposition (MLCD), employ a fixed multivariate mean curve extraction method for signal decomposition. Consequently, these methods often exhibit suboptimal performance when decomposing different multi-channel signals. This study defines nine multivariate mean curve extraction methods and introduces the multivariate intrinsic wave-characteristic decomposition (MIWD) method based on the principles of mean curve optimization and an adaptive projection method. MIWD dynamically optimizes the multivariate mean curve during the decomposition process, resulting in superior performance in terms of decomposition accuracy, capability, and orthogonality compared to MEMD and MLCD. Furthermore, we apply MIWD to gear fault diagnosis, and simulation and experimental results affirm the superiority of MIWD.
Cross-device target migration intelligent diagnosis method of wind power gearbox faults
Authors: Guo Panpan , Cui Ben , Zhang Wenbin
Published: October 2023

The current convolutional neural network (CNN) deep learning algorithm for wind power gearbox fault diagnosis requires a substantial amount of high-quality tagged data from testbeds to achieve accurate results. However, it may not perform well in practical engineering scenarios where there is limited fault tag data and incomplete fault information. To overcome this challenge, a novel approach utilizing cross-device target transfer for intelligent diagnosis of wind turbine gearbox faults is proposed. This method transforms the fault diagnosis of wind turbine gearboxes into an image recognition and classification task. Initially, the source domain gearbox testbed data is subjected to dimension transformation using the Gramian angular difference field technique, resulting in the generation of small sample two-dimensional images. This transformation simulates the limited fault tag data scenario encountered in practical engineering. Once the fault features have been augmented, the small sample source domain gearbox testbed data is fed into the IConvNeXt deep CNNs. These CNNs are interconnected and specifically designed for the field. They aim to extract and recognize fault features, thereby creating a pre-training model. The pre-training model is then transferred to the target domain wind power gearbox data for fault diagnosis experiments. The results of these experiments demonstrate the significant effectiveness of the proposed method in recognizing faults in small sample wind power gearboxes within the target domain. Overall, this method successfully achieves the goal of intelligent fault diagnosis through target transfer. It addresses the challenge of limited fault tag data and incomplete fault information, thereby enhancing the performance of CNNs in practical engineering scenarios.
Impact of local chemical ordering on deformation mechanisms in single-crystalline CuNiCoFe high-entropy alloys: a molecular dynamics study
Authors: Shuang Siyao , Liang Yanxiang , Zhang Xie , Yuan Fupin , Kang Guozheng , Zhang Xu
Published: October 2023

High-entropy alloys (HEAs), composed of multiple constituent elements with concentrations ranging from 5% to 35%, have been considered ideal solid solution of multi-principal elements. However, recent experimental and computational studies have demonstrated that complex enthalpic interactions among constituents lead to a wide variety of local chemical ordering (LCO) at lower temperatures. HEAs containing Cu typically decompose by forming of Cu-rich phases during annealing, thus affecting mechanical properties. In this study, CuNiCoFe HEA was chosen as a model with a tendency for Cu segregation at low temperatures. The formation of LCO and its impact on the deformation behaviors in the single-crystalline CuNiCoFe HEA were studied via molecular dynamics simulations. Our results demonstrate that CuNiCoFe HEA decomposes by Cu clustering, in agreement with prior experimental and computational studies, owing to insufficient configuration entropy to compete against the mixing enthalpy at lower temperatures. A softening in ultimate stress in the LCO models was observed compared to the random solid solution models. The softening is due to the lower unstable stacking fault energy, which determines the nucleation event of dislocations, thereby rationalizing the dislocation nucleation in the Cu-rich regions and the softening of the overall ultimate strength in the LCO models. Additionally, the inhomogeneous FCC–BCC transformation is closely associated with concentration inhomogeneity. CuNiCoFe HEA with LCO can be regarded as composites, consisting of clusters with different properties. Consequently, concentration inhomogeneity induced by LCO profoundly impacts the mechanical properties and deformation behaviors of the HEA. This study provides insights into the effect of LCO on the mechanical properties of CuNiCoFe HEAs, which is crucial for developing HEAs with tailored properties for specific applications.
Machine learning based phase prediction and powder metallurgy assisted experimental validation of medium entropy compositionally complex alloys
Authors: Das Priyabrata , Pandey Pulak Mohan
Published: October 2023

Medium entropy alloys (MEAs) are a subset of compositionally complex alloys whose mixing entropy lies between R and 1.5 R where R is the universal gas constant. The properties of MEAs largely depend on the phases present in the alloy such as solid solution (SS), solid solution + intermetallic (SS + IM) and amorphous (AM). Hence, the correct prediction of phases can enable the efficient selection of material compositions with anticipated properties. In this paper, three machine learning (ML) algorithms viz. k nearest neighbors (KNNs), artificial neural network (ANN), and random forest (RF) were employed for the ternary phase classification problem. An MEA dataset was constructed by utilizing all reported MEAs till February 2023 to the best of authors’ knowledge. The study implied that the use of only three features (mixing enthalpy, atomic size mismatch, and a strain energy related parameter) were sufficient for the phase prediction in MEAs. Among the three ML algorithms, ANN had the highest macro averaged F1 score (86.7%) and accuracy (87.3%) in predicting the phases in MEAs, while RF has the lowest macro F1 score (84.67%) and accuracy (84.8%). However, for phase prediction between single phase SS and multi-phase SS (binary classification), distance-based algorithm (KNN) was found to be suitable. The prediction performance of ML model over a completely unseen data was assessed in the case study section. The experimentally determined phase details of three new MEA compositions fabricated by powder metallurgy route was also included in the unseen dataset. The SS and AM phases were correctly labeled nine times out of eleven instances by using ANN model. However, the model prediction for SS + IM phase was found to be less reliable (three out of five correct) owing to its relatively poor F1 score.
Polyvinyl alcohol-based economical triboelectric nanogenerator for self-powered energy harvesting applications
Authors: Amini Sebghatullah , Muktar Ahmed Rumana Farheen Sagade , Ankanathappa Sangamesha Madanahalli , Sannathammegowda Krishnaveni
Published: October 2023

Triboelectric nanogenerators (TENGs) have emerged as a promising alternative for powering small-scale electronics without relying on traditional power sources, and play an important role in the development of the internet of things (IoTs). Herein, a low-cost, flexible polyvinyl alcohol (PVA)-based TENG (PVA-TENG) is reported to harvest low-frequency mechanical vibrations and convert them into electricity. PVA thin film is prepared by a simple solution casting technique and utilized to serve as the tribopositive material, polypropylene film as tribonegative, and aluminum foil as electrodes of the device. The dielectric-dielectric model is implemented with an arch structure for the effective working of the PVA-TENG. The device showed promising electrical output by generating significant open-circuit voltage, short-circuit current, and power . Also, PVA-TENG is subjected to a stability test by operating the device continuously for 5000 cycles. The result shows that, the device is mechanically durable and electrically stable. Further, the as-fabricated PVA-TENG is demonstrated to show feasible applications, such as charging two commercial capacitors with capacitances 1.1 and 4.7 μF and powering green light-emitting diodes. The stored energy in the 4.7 μF capacitor is utilized to power a digital watch and humidity and temperature sensor without the aid of an external battery. Thus, the PVA-TENG facilitates ease of fabrication, robustness, and cost-effective strategy in the field of energy harvesting for powering lower-grid electronics by demonstrating their potential as a sustainable energy source.
Dose reduction in dynamic synaptic vesicle glycoprotein 2A PET imaging using artificial neural networks
Authors: Li Andi , Yang Bao , Naganawa Mika , Fontaine Kathryn , Toyonaga Takuya , Carson Richard E , Tang Jing
Published: October 2023

Objective. Reducing dose in positron emission tomography (PET) imaging increases noise in reconstructed dynamic frames, which inevitably results in higher noise and possible bias in subsequently estimated images of kinetic parameters than those estimated in the standard dose case. We report the development of a spatiotemporal denoising technique for reduced-count dynamic frames through integrating a cascade artificial neural network (ANN) with the highly constrained back-projection (HYPR) scheme to improve low-dose parametric imaging. Approach. We implemented and assessed the proposed method using imaging data acquired with 11C-UCB-J, a PET radioligand bound to synaptic vesicle glycoprotein 2A (SV2A) in the human brain. The patch-based ANN was trained with a reduced-count frame and its full-count correspondence of a subject and was used in cascade to process dynamic frames of other subjects to further take advantage of its denoising capability. The HYPR strategy was then applied to the spatial ANN processed image frames to make use of the temporal information from the entire dynamic scan. Main results. In all the testing subjects including healthy volunteers and Parkinson’s disease patients, the proposed method reduced more noise while introducing minimal bias in dynamic frames and the resulting parametric images, as compared with conventional denoising methods. Significance. Achieving 80% noise reduction with a bias of −2% in dynamic frames, which translates into 75% and 70% of noise reduction in the tracer uptake (bias, −2%) and distribution volume (bias, −5%) images, the proposed ANN+HYPR technique demonstrates the denoising capability equivalent to a 11-fold dose increase for dynamic SV2A PET imaging with 11C-UCB-J.
Ionization of uracil molecule in collisions with 2.5-MeV/u Si12+ ions
Authors: Maurya Sanjeev Kumar , Chakraborty Debasmita , Bhogale Abhijeet , Bagdia Chandan , Ghag Kalpesh , Gulyás Laszlo , Tribedi Lokesh C
Published: October 2023

The energy and angular distribution of electron emission from a RNA base molecule, uracil (C
4
H
4
N
2
O
2), are investigated in collisions with 2.5-MeV/u Si12+ ions under high perturbation strength. The absolute double differential cross sections (DDCS) are measured using electron spectroscopy for emission angles between 20° to 160° in the electron energy range 1-620 eV. The single differential cross sections (SDCS) are evaluated by integrating the DDCS over emission angles or energies. The measured cross sections (DDCS and SDCS) are compared with the state-of-the-art continuum distorted wave-eikonal initial state (CDW-EIS) theoretical model. The DDCS obtained by the CDW-EIS is found to provide better agreement with the measurements in the backward angles. With an increase in perturbation strength from 0.5 to 1.19 a.u., the DDCS is found to increase by 10 times in comparison to the earlier reported uracil data for 3.5-MeV/u bare C-ions [Phys. Rev. A 87, 032716 (2013)]. The significant enhancement in the TCS is found for the total cross section in case of Si12+ ions over that predicted by a scaling law as derived for lower charge state projectiles. The forward-backward angular asymmetry is found to increase monotonically with the velocity of emitted electrons and shows very good agreement with the model. For a comparative study, the DDCS is also measured for oxygen molecule using same ion impact, which is found to be about ten times lower than that for the uracil. The forward-backward angular asymmetry for oxygen is found to be almost the same as uracil.
Comprehensive investigation of sputtering deposition pressure effects on a-InGaZnO Schottky diodes
Authors: Kurtuluş Gürkan , Asar Tarık , Özçelik Süleyman
Published: October 2023

The effects of Ar sputtering deposition pressure on the optical, structural, morphological, and electrical properties of amorphous InGaZnO thin films were investigated. The InGaZnO thin films, which have amorphous structures determined by grazing incidence x-ray diffraction, contained In, Ga, Zn, and O confirmed by secondary ion mass spectrometry method. Additionally, when the thicknesses of the deposited thin films are examined, it was seen that the profilometer measurement results of the crater formed by secondary ion mass spectrometer and scanning electron microscope measurement results are nearly similar, and it is approximately 100 nm. The surface roughness, obtained from Atomic Force Microscopy results, show that decreased up to a particular value with the increase of the working pressure, and then the surface roughness increased. The optical band gaps of the films were obtained in the range of 3.50 eV−3.58 eV via Tauc relation by using the Ultraviolet-Visible measurements carried out in the wavelength range of 200 nm−1100 nm. It was seen that the optical band gap was decreased with the increase in Ar pressure. The electrical properties of InGaZnO thin film-based Schottky diodes, such as the barrier height, ideality factor, saturation current, series resistance, and shunt resistance, have also been studied comprehensively. The electrical results showed that diode properties change with increasing deposition pressure.
Novel reconstruction method of angle-limited backprojection (ALBP) for low-dose dental panoramic X-ray imaging
Authors: Yang Hyesun , Shim Jiyong , Jeon Duhee , Cho Hyosung
Published: October 2023

Panoramic radiography is a popular two-dimensional X-ray imaging modality in dentistry. It
produces a single image of the overall facial view, including the maxillary and mandibular arches
and supporting structures. Panoramic images are typically reconstructed using the shift-and-add
(SAA) algorithm, in which only structures within a certain image layer are in focus, and others
are out of focus on the panoramic image. As the clinical use of panoramic radiography has grown
rapidly, radiologists are continuously seeking ways to reduce the radiation dose to patients. This
study proposes a novel panoramic reconstruction method called the angle-limited backprojection
(ALBP) algorithm for low-dose panoramic X-ray imaging. In ALBP, X-rays that meet the angular
criterion established in this study are selected from the measured panoramic projection data and
then backprojected onto the spherical voxels placed along the dental arch, as in a typical
computed tomography reconstruction. The angular criterion selects X-rays that pass through a given
spherical voxel and simultaneously have directional vectors within a prespecified angular range
concerning the directional vector at the corresponding source position. To validate the efficacy
of the proposed reconstruction method, we conducted a numerical simulation and experiment and
investigated the image characteristics. Panoramic images were reconstructed using the SAA and ALBP
algorithms with full and half (i.e., half radiation dose) panoramic projections, and their image
quality was quantitatively evaluated using the intensity profile and universal quality index
(UQI). The image quality of the ALBP with half projections was similar to that of the SAA with
full projections, indicating the efficacy of the proposed method. Accordingly, our results
demonstrated the potential for radiation dose reduction in panoramic X-ray imaging.
Morawetz’s contributions to the mathematical theory of transonic flows, shock waves, and partial differential equations of mixed type
Authors: Chen Gui-Qiang
Published: October 2023

This article is a survey of Cathleen Morawetz’s contributions to the mathematical theory of transonic flows, shock waves, and partial differential equations of mixed elliptic-hyperbolic type. The main focus is on Morawetz’s fundamental work on the nonexistence of continuous transonic flows past profiles, Morawetz’s program regarding the construction of global steady weak transonic flow solutions past profiles via compensated compactness, and a potential theory for regular and Mach reflection of a shock at a wedge. The profound impact of Morawetz’s work on recent developments and breakthroughs in these research directions and related areas in pure and applied mathematics are also discussed.