bluuebunny/crossref_metadata_2025 huggingface dataset:
Antecedents of energy consumption intention to usage by home energy management system: a case study of Galicia's homes in Spain
Authors: Al Muala Zaid A. , Bany Issa Mohammad A. , Fernández Rodríguez José Julio , Bello Bugallo Pastora M.
Published: March 2024

The residential sector is a substantial consumer of energy in Spain. A new electricity tariff was applied in Spain to make home consumers manage their energy consumption based on the variation of electricity price during the day, which contributes to energy security, increases the penetration of Renewable Energy Sources (RES) into the grid, maintains grid stability, and reduce CO2 emissions. To ensure the successful implementation of the new Demand Response (DR) program, it is necessary to investigate the factors that might affect home energy consumers to use the Home Energy Management System (HEMS). This work aims to examine the factors that affect the Spanish home energy consumers' acceptance to participate in DR, which have not been studied yet after the new electricity tariff. In addition, highlighting the role of economic benefits and environmental awareness factors in the acceptance of participating in DR using HEMS. The Technology Acceptance Model (TAM) is used in this work with four independent factors, attitude toward use as a mediating effect, and one dependent variable of intention to use, then hypotheses were set for each. The selected research method was a diagnostic survey technique through a standardized survey questionnaire distributed in person and online, that Galicia, Northwest Spain was taken as a case study. In terms of the statistical results of Probability value (P-value) and Critical Ratio (C.R.), it was found that the family's economic benefits and environmental awareness affect the attitude toward using HEMS after the new electricity tariff in Spain and attitude toward using HEMS has a significant impact on the intention to use HEMS. However, the usefulness and ease of using HEMS for managing energy consumption do not influence the consumers' attitudes toward adopting HEMS. The direct effect of usefulness on the intention of using HEMS is higher than the indirect effect through attitude. Thus, the mediating effect of the attitude to the relationships between usefulness and intention to use is not significant. The results help the Spanish policymakers to draw up policies to effectively disseminate strategies to encourage home consumers to contribute to energy security and assist energy management researchers in incorporating key factors that impact energy consumers into their proposed models. By doing so, these models can clarify the financial and environmental advantages of effective energy consumption management, thereby encouraging energy consumers to adopt more sustainable practices.
Le taux de retour en énergie (EROI) et son importance dans l’évaluation des performances des systèmes énergétiques
Authors: Bonhomme Gérard , Treiner Jacques
Published: March 2024

Satisfaire les besoins en énergie de nos sociétés, dans un contexte de lutte contre le réchauffement climatique et de perspectives d’épuisement des stocks de combustibles fossiles et de ressources minérales, requiert de mettre en œuvre des solutions alternatives à bas carbone. Le cout du MWh est sans doute un critère utile, mais des critères physiques sont indispensables pour évaluer les solutions technologiques et les scénarios énergétiques envisageables.

Le principal de ces critères fondés sur des grandeurs physiques est le « taux de retour énergétique » (EROI), qui mesure l’efficacité d’un système à fournir à la société une énergie utile pour les secteurs d’activités autres que le secteur énergétique lui-même. D’autres aspects doivent aussi être considérés, comme la disponibilité des ressources, les surfaces mobilisées, les besoins en minéraux, les risques industriels et les impacts sur l’environnement et la santé.
PET-Bildgebung bei der Entwicklung von mRNA-Vakzinen
Authors: Miederer Matthias
Published: March 2024

Beim Einsatz von immunmodulatorischen Therapien ist eine dynamische Entwicklung im Gange, mit großen Erfolgen bei einer Vielzahl von Tumorerkrankungen. Dabei stehen vereinfacht typischerweise T-Zellen im Fokus des Wirkmechanismus. Durch Interventionen in vivo oder ex vivo gelingt zunehmend eine Steuerung der T-Zell-Funktion hin zu einer tumorspezifischen Wirkung. Für die Entwicklung solcher Therapien und zur Erforschung zugrundeliegender Mechanismen kommt häufig funktionelle Bildgebung zum Einsatz, bei der z.B. Signalwege oder Zellen mit Fluoreszenzfarbstoffen in Tiermodellen dargestellt werden. Darüber hinaus besteht mit der Positronenemissionstomografie eine Bildgebung mit der funktionelle Wege in vivo zuverlässig abgebildet werden können. Somit können z.B. FDG-PET und Iod-124-PET als gut verfügbare und etablierte Methoden einen Beitrag zur Entwicklung neuer Therapien leisten. Die Vakzinierung mit mRNA ist eines der dynamischen Felder in der immunologischen Therapie, bei der immunologische Modifikationen in vivo eine Tumorwirkung erreichen können. Mittels PET konnten einzelne Aspekte dieses Wirkmechanismus abgebildet werden und somit exemplarisch das Potenzial der PET-Bildgebung bei der Entwicklung neuer Therapieansätze gezeigt werden.
Immuntherapie von Schilddrüsenkarzinomen
Authors: Essler Markus
Published: March 2024

In den letzten Jahren hat die Immuntherapie mit „checkpoint-inhibitoren“ (CI) wie Pebrolizumab, Ipilimumab und Nivulomab die
Behandlung von metastasierten malignen Melanomen, dem „non-small-cell-lung-cancer“ (NSCLC) und anderen bis dahin unzureichend
therapierbaren Tumorentitäten erheblich verbessert, wenn nicht gar revolutioniert. Zahlreiche
prospektive und randomisierte Studien belegen dies mit hoher Evidenz. Bei der Therapie mancher
Tumorentitäten spielen CI allerdings keine zentrale Rolle. Hierzu gehören die
Schilddrüsenkarzinome. Ein Grund hierfür ist die Effektivität der Behandlung mit primärer
Operation und ablativer Radioiodtherapie. Die Prognose der meisten Schilddrüsenkarzinome ist
durch diese Therapieoptionen mit 5-Jahres-Überlebensraten von mehr als 95% sehr günstig.
Klinische Studien mit CIs sind daher in diesem Bereich wohl wenig relevant, da sie auch bei
positivem Ergebnis das Überleben nur unwesentlich verbessern könnten. Die Prognose der
schlecht differenzierten-, iodnegativen, anaplastischen und medullären Schilddrüsenkarzinome
ist hingegen weit ungünstiger. Es wurden zwar Multikinaseinhibitoren wie Lenvatinib, Sorafenib
und Cabozantinib mit einer Verbesserung des „progressionsfreien Überlebens“ (PFS) zur
Behandlung zugelassen, keines dieser Medikamente hatte jedoch Einfluss auf das Gesamtüberleben
(OS). Zudem sind die MKIs für viele Patienten wenig verträglich und anfällig für die
Entwicklung von Resistenzen. Es ist naheliegend, dass die Immuntherapie am ehesten für
Patientengruppen getestet werden sollte, die nicht (mehr) für eine Operation oder
Radioiodtherapie infrage kommen und für die keine Option einer Therapie mit MKIs mehr besteht.
In diesem Zusammenhang wurden global zahlreiche Studien gestartet, von denen allerdings nur
wenige bereits publiziert wurden. In Zukunft sind jedoch evidenzbasierte immuntherapeutische
Optionen für die Schilddrüsenmalignome zu erwarten. Es ist erfreulich, dass die erste
erfolgreiche klinische Studie zur Immuntherapie des anaplastischen Schilddrüsenkarzinoms
(ATLEB-Studie) von einer deutschen Arbeitsgruppe durchgeführt wurde.
Begleitende Autoimmunphänomene bei Hashimoto-Thyreoiditis
Authors: Schinner Sven
Published: March 2024

Autoimmune Schilddrüsenerkrankungen sind häufig: Die Hashimoto-Thyreoiditis tritt häufiger als der Morbus Basedow auf und hat eine Prävalenz von ca. 1% in Deutschland (definiert nach Antikörpernachweis und typischem Ultraschallbefund). Die Prävalenz von Positivität für Schilddrüsenantikörper ist mit ca. 7% deutlich höher.

Diese Erkrankungen können Teil von Autoimmunsyndromen sein. Dies bedeutet, dass es zu einer Häufung verschiedener Autoimmunerkrankungen in einer Person oder einer Familie kommen kann.

Es können endokrine Organe (Schilddrüse, Nebenschilddrüsen, Nebennieren, Pankreas, Ovarien), aber auch nicht endokrine Organe betroffen sein: Hierzu zählen die chronische mukokutane Candidiasis, Typ-A-Gastritis, Alopezie, Vitiligo, Zöliakie und Myasthenia gravis.

Nach der Kombination dieser Autoimmunerkrankungen ergeben sich Hinweise auf definierte sogenannte polyglanduläre Autoimmunsyndrome.

Man definiert das polyglanduläre Autoimmunsyndrom Typ 1 (APS-1) mit den Leiterkrankungen chronische mukokutane Candidiasis, Hypoparathyreoidismus und Morbus Addison.

Weiterhin das polyglanduläre Autoimmunsyndrom Typ 2 (APS-2) mit den Leiterkrankungen Diabetes mellitus Typ 1, autoimmune Schilddrüsenerkrankung (Hashimoto-Thyreoiditis/Morbus Basedow) und Morbus Addison.

Im Prinzip können diese Erkrankungen zu jedem Lebenszeitpunkt auftreten, wobei es aber Altersgipfel gibt, wann sich die Erkrankungen und Syndrome typischerweise manifestieren.
Sarkoidose – Mechanismen und Bildgebung
Authors: Gaertner Florian Christoph , Skowasch Dirk
Published: March 2024

Die Sarkoidose ist eine granulomatös-entzündliche Multisystemerkrankung, die sich am häufigsten in der Lunge und in den mediastinalen Lymphknoten manifestiert, prinzipiell jedoch jedes Organsystem betreffen kann. Die Vielzahl der möglicherweise betroffenen Organsysteme und die daraus resultierende häufig unspezifische Symptomatik kann die klinische Diagnostik vor Herausforderungen stellen. Schwerwiegende Komplikationen der Sarkoidose sind insbesondere die Entwicklung einer Lungenfibrose sowie bei kardialer Beteiligung die Entwicklung einer Herzinsuffizienz und das Auftreten maligner Herzrhythmusstörungen. Die radiologische Bildgebung, insbesondere die Computertomografie, ist in erster Linie zur Darstellung der pulmonalen Beteiligung und der mediastinalen Lymphadenopathie geeignet. Der MRT kommt insbesondere ein Stellenwert in der Diagnostik der ZNS-Beteiligung einer Sarkoidose zu sowie in der Beurteilung möglicher kardialer Sarkoidosemanifestationen. Bezüglich der nuklearmedizinischen Diagnostik der Sarkoidose liegt der Schwerpunkt auf der FDG-PET/CT, die Szintigrafie mit Gallium-67-Zitrat besitzt keinen relevanten Stellenwert mehr. Prinzipiell kann die FDG-PET/CT eine Sarkoidosebeteiligung in einer Vielzahl von Organsystemen darstellen, besondere Bedeutung kommt der FDG-PET/CT jedoch in der Diagnostik einer kardialen Sarkoidosebeteiligung zu sowie in der Identifikation möglicher Biopsielokalisationen zur Diagnosesicherung und der in Beurteilung der entzündlichen Aktivität im Rahmen eines Therapiemonitorings. Nachteile der FDG-PET/CT im Rahmen der kardialen Sarkoidosediagnostik liegen in der absoluten Notwendigkeit einer diätetischen Patientenvorbereitung, die insbesondere durch die Compliance der Patienten eingeschränkt sein kann. Spezifischere PET-Tracer, die keine spezifische Patientenvorbereitung erfordern, können sich hier als hilfreich erweisen, wie z.B. [68Ga]Ga-DOTATOC zur Darstellung der Expression des Somatostatinrezeptors auf Entzündungszellen.
Den Horizont Erweitern – Ausbildungspraktikum in Jordanien
Authors: Schenk Anca
Published: March 2024

Anca Schenk absolvierte im dritten Ausbildungsjahr ein Praktikum in Jordanien und berichtet von ihren Eindrücken. In Amman, der jordanischen Hauptstadt, erhielt sie einen interessanten Einblick in die Ergotherapie am Jordan University Hospital und sammelte viele neue Erfahrungen und Erkenntnisse – für die Ausbildung und das Leben.
Drei Tage Ergo-Erleben – ergotage 2024
Authors: Holtmeier Lisa
Published: March 2024

Vom 26. bis zum 28. Januar 2024 zeigten sich die ergotage im Rahmen der TheraPro in neuer Formation: Angelehnt an die Thieme-Fachzeitschriften fand neben dem Neuroreha-Tag und dem ergopraxis-Tag auch die Premiere des Handreha-Tages statt. Jeweils 250–300 Besucher*innen erweiterten in Stuttgart ihr Wissen und vernetzten sich mit Kolleg*innen.
Verständliches und anwenderfreundliches Manual – ETpro
Authors: Kranz Florence
Published: March 2024

Mit dem ETpro steht Ergotherapeut*innen ein Dokumentationstool zur Verfügung, das gesetzliche Anforderungen erfüllt und auf einem zeitgemäßen professionellen Selbstverständnis basiert. Um dieses Tool tatsächlich in ihrer Praxis nutzen zu können, müssen Ergotherapeut*innen die Erläuterungen im zugehörigen Manual verstehen und umsetzen können. Achim Hallmanns und Fritz Winklmeier haben in ihrer Bachelorarbeit untersucht, inwieweit diese Voraussetzungen erfüllt sind.
The multifaceted influence of multidisciplinary background on placement and academic progression of faculty
Authors: Lyu Wenjing , Huang Yuanhao , Liu Jin
Published: March 2024

This study delves into the implications of faculty’s multidisciplinary educational backgrounds on their academic placement and upward mobility, and underscores the moderating effects of gender and academic inbreeding. Grounded in the theories of knowledge recombination and limited attention, the study finds that having a multidisciplinary background tends to challenge favorable academic placements and upward mobility. However, it also shows that male faculty and those who have graduated from the same institution where they work (academic inbreeding) are better at overcoming these challenges. Additionally, elite universities seem to have a higher regard for multidisciplinary backgrounds. This study provides insights for individuals navigating academic careers and offers valuable information for university leaders and policymakers.
What do you do or with whom? Understanding happiness with the tourism experience: an AI approach applied to Instagram
Authors: Blanco-Moreno Sofía , González-Fernández Ana M. , Muñoz-Gallego Pablo Antonio , Egger Roman
Published: March 2024

More and more tourists are sharing their experiences on their social media through a combination of photos, texts, and hashtags. But there is a scarcity of studies in literature on analyzing tourists’ visual content in relation to tourism destinations. To address this gap in literature, this study explores how and with whom users express the greatest happiness in holiday destinations, and how they share it with their community, through a mixed methods approach composed of analysis of images, text, and metadata. This approach allows us to address the objective of this research, which is the prediction of the happiness felt by tourists during their experience, using innovative techniques that allow the independent variables to be obtained. To predict tourist satisfaction, two sources of data, photos and texts, are analyzed: a novel approach and little explored in the literature, but necessary due to the interaction of both variables. This study applies various artificial intelligence analyses on visual content (deep learning), and textual and metadata content (machine learning) to 39,235 Instagram posts shared by tourists since the emergence of Instagram thirteen years ago, at a cultural and gastronomic tourist destination. The findings of the visual content analysis showed that socialization and company, that is, traveling and interacting with people, was a key aspect of a positive tourism experience. In addition, the gender of the people with whom they traveled, and the tourist’s narcissism were also key aspects in the generation and expression of positive emotions. Regarding the analysis of the textual content, the results showed that when tourists enjoyed a positive experience, they became more involved in the generation of content, that is, they showed their happiness through positive words.
Designing workflows for materials characterization
Authors: Kalinin Sergei V. , Ziatdinov Maxim , Ahmadi Mahshid , Ghosh Ayana , Roccapriore Kevin , Liu Yongtao , Vasudevan Rama K.
Published: March 2024

Experimental science is enabled by the combination of synthesis, imaging, and functional characterization organized into evolving discovery loop. Synthesis of new material is typically followed by a set of characterization steps aiming to provide feedback for optimization or discover fundamental mechanisms. However, the sequence of synthesis and characterization methods and their interpretation, or research workflow, has traditionally been driven by human intuition and is highly domain specific. Here, we explore concepts of scientific workflows that emerge at the interface between theory, characterization, and imaging. We discuss the criteria by which these workflows can be constructed for special cases of multiresolution structural imaging and functional characterization, as a part of more general material synthesis workflows. Some considerations for theory–experiment workflows are provided. We further pose that the emergence of user facilities and cloud labs disrupts the classical progression from ideation, orchestration, and execution stages of workflow development. To accelerate this transition, we propose the framework for workflow design, including universal hyperlanguages describing laboratory operation, ontological domain matching, reward functions and their integration between domains, and policy development for workflow optimization. These tools will enable knowledge-based workflow optimization; enable lateral instrumental networks, sequential and parallel orchestration of characterization between dissimilar facilities; and empower distributed research.
Chaos in gene regulatory networks: Effects of time delays and interaction structure
Authors: Öztürk Dilan , Atay Fatihcan M. , Özbay Hitay
Published: March 2024

In biological system models, gene expression levels are typically described by regulatory feedback mechanisms. Many studies of gene network models focus on dynamical interactions between components, but often overlook time delays. Here we present an extended model for gene regulatory networks with time delayed negative feedback, which is described by delay differential equations. We analyze nonlinear properties of the model in terms of chaos and compare the conditions with the benchmark homogeneous gene regulatory network model. Chaotic dynamics depend strongly on the inclusion of time delays, but the minimum motifs that show chaos differ when both original and extended models are considered. Our results suggest that, for a particular higher order extension of the gene network, it is possible to observe chaotic dynamics in a two-gene system without adding any self-inhibition. This finding can be explained as a result of modification of the original benchmark model induced by previously unmodeled dynamics. We argue that the inclusion of additional parameters in regulatory gene circuit models substantially enhances the likelihood of observing non-periodic dynamics.
Coherent x-ray spontaneous emission spectroscopy of conical intersections
Authors: Jadoun Deependra , Kowalewski Markus
Published: March 2024

Conical intersections are known to play a vital role in many photochemical processes. The breakdown of the Born–Oppenheimer approximation in the vicinity of a conical intersection causes exciting phenomena, such as the ultrafast radiationless decay of excited states. The passage of a molecule through a conical intersection creates a coherent superposition of electronic states via nonadiabatic couplings. Detecting this coherent superposition may serve as a direct probe of the conical intersection. In this paper, we theoretically demonstrate the use of coherent spontaneous emission in samples with long-range order for probing the occurrence of a conical intersection in a molecule. Our simulations show that the spectrum contains clear signatures of the created coherent superposition of electronic states. We investigate the bandwidth requirements for the x-ray probes, which influence the observation of coherent superposition generated by the conical intersection.
Optimization of the optical path length amplitude for interferometric photothermal gas and aerosol sensing considering advection: A theoretical study
Authors: Radeschnig Ulrich , Bergmann Alexander , Lang Benjamin
Published: March 2024

Photothermal spectroscopy, and more specifically photothermal interferometry (PTI), is a highly sensitive technique for measuring gas and aerosol concentrations. Numerous implementations of different PTI configurations have demonstrated the versatility of the technique. This theoretical study presents a comprehensive analysis and an optimization of the PTI optical path length (OPL) amplitude using characteristic times. We investigate how the OPL amplitude depends on the dimensions and orientations of the interferometer laser beam and the continuous-wave excitation laser beam. This analysis quantifies the impact of advection on the OPL amplitude based on the relative orientation of the two laser beams and the gas flow direction. It is analytically shown that the possibilities for photothermal OPL amplitude optimization are limited when thermal diffusion is dominant. Theoretically, advection has the potential to double or cancel the OPL amplitude, depending on the specific configurations. In summary, we provide an in-depth understanding of the design and parameter considerations required when tailoring and optimizing a PTI sensor for different fields of applications.
A correction method for radial distortion and nonlinear response of infrared cameras
Authors: Shu Shuangbao , Fu Yufeng , Liu Shenglin , Zhang Yuzhong , Zhang Tengda , Wu Tianqi , Gao Xinyu
Published: March 2024

The key feature of non-contact temperature measurement provided by infrared (IR) cameras underpins their versatility. However, the accuracy of temperature measurements with IR cameras depends on imaging quality due to their non-contact nature, such as the lens, body temperature, and measurement environment. This paper addresses the correction of radial distortion and nonlinear response issues in IR cameras. To address radial distortion, we have designed a passive checkerboard calibration board specifically for infrared cameras. This board is used to calibrate the IR camera and derive the necessary camera parameters. Subsequently, these parameters are applied during the actual measurement process to rectify radial distortion effectively. Building on the radial distortion correction method mentioned above, we propose a multi-point segmented calibration approach that considers different temperature ranges and imaging regions. This method alleviates the issue of reduced temperature measurement accuracy due to variations in camera responses by computing gain and offset coefficient matrices for each temperature range. Experimental results demonstrate the effectiveness of the calibration board in correcting radial distortion in IR cameras, with a mean reprojection error of less than 0.16 pixels. Regarding the nonlinear response problem, the introduced method significantly reduces the relative error in temperature measurement. In the verification phase, spanning from 100 to 500 °C, the average relative error in temperature measurement decreases by 0.49% from 1.61% before and after correction, which highlights a substantial improvement in temperature measurement accuracy. This work gives a useful reference to improve the imaging quality and temperature measurement accuracy using infrared cameras.
In situ single-molecule investigations of the impacts of biochemical perturbations on conformational intermediates of monomeric α-synuclein
Authors: Huang Wenmao , Liu Jingzhun , Le Shimin , Yao Mingxi , Shi Yi , Yan Jie
Published: March 2024

α-Synuclein aggregation is a common trait in synucleinopathies, including Parkinson's disease. Being an unstructured protein, α-synuclein exists in several distinct conformational intermediates, contributing to both its function and pathogenesis. However, the regulation of these monomer conformations by biochemical factors and potential drugs has remained elusive. In this study, we devised an in situ single-molecule manipulation approach to pinpoint kinetically stable conformational intermediates of monomeric α-synuclein and explore the effects of various biochemical factors and drugs. We uncovered a partially folded conformation located in the non-amyloid-β component (NAC) region of monomeric α-synuclein, which is regulated by a preNAC region. This conformational intermediate is sensitive to biochemical perturbations and small-molecule drugs that influencing α-synuclein's aggregation tendency. Our findings reveal that this partially folded intermediate may play a role in α-synuclein aggregation, offering fresh perspectives for potential treatments aimed at the initial stage of higher-order α-synuclein aggregation. The single-molecule approach developed here can be broadly applied to the study of disease-related intrinsically disordered proteins.
n-type semiconductor with energy storage made from chitosan
Authors: Fukuhara Mikio , Yokotsuka Tomonori , Kayamori Shunsuke , Isogai Akira , Hashida Toshiyuki
Published: March 2024

Chitosan, obtained from crustaceans such as crabs and shrimp, has been mainly used in medicine; however, no studies on its use in electronic applications with semiconducting and large storage properties have been reported. Here, we report an n-type semiconducting biomaterial with energy storage properties of 694.4 mJ/m2 consisting of a chitosan nanofiber (ChNF) film with N-type negative resistance. The ChNF generates an alternative-current wave with a frequency of 7.8 MHz at a threshold voltage of 187 MV/m from a direct-current voltage source, with the switching effect of a third-order resistance change. This is due to the Gunn effect, caused by the repeated voltage-induced generation of a strong electric field domain (electric double layer) at the cathode and its disappearance at the anode of the ChNF device. Electron spin resonance spectral analysis showed that conducting electrons of the ChNF were identified as radicals on the aminyl radical, N·H. Paper electronics made from marine products are a great boon to a renewable society.
Molecular driving forces for water adsorption in MOF-808: A comparative analysis with UiO-66
Authors: Frank Hilliary O. , Paesani Francesco
Published: March 2024

Metal–organic frameworks (MOFs), with their unique porous structures and versatile functionality, have emerged as promising materials for the adsorption, separation, and storage of diverse molecular species. In this study, we investigate water adsorption in MOF-808, a prototypical MOF that shares the same secondary building unit (SBU) as UiO-66, and elucidate how differences in topology and connectivity between the two MOFs influence the adsorption mechanism. To this end, molecular dynamics simulations were performed to calculate several thermodynamic and dynamical properties of water in MOF-808 as a function of relative humidity (RH), from the initial adsorption step to full pore filling. At low RH, the μ3-OH groups of the SBUs form hydrogen bonds with the initial water molecules entering the pores, which triggers the filling of these pores before the μ3-OH groups in other pores become engaged in hydrogen bonding with water molecules. Our analyses indicate that the pores of MOF-808 become filled by water sequentially as the RH increases. A similar mechanism has been reported for water adsorption in UiO-66. Despite this similarity, our study highlights distinct thermodynamic properties and framework characteristics that influence the adsorption process differently in MOF-808 and UiO-66.
Time dependent vibrational electronic coupled cluster (VECC) theory for non-adiabatic nuclear dynamics
Authors: Bao Songhao , Raymond Neil , Nooijen Marcel
Published: March 2024

A time-dependent vibrational electronic coupled-cluster (VECC) approach is proposed to simulate photo-electron/UV-VIS absorption spectra as well as time-dependent properties for non-adiabatic vibronic models, going beyond the Born–Oppenheimer approximation. A detailed derivation of the equations of motion and a motivation for the ansatz are presented. The VECC method employs second-quantized bosonic construction operators and a mixed linear and exponential ansatz to form a compact representation of the time-dependent wave-function. Importantly, the method does not require a basis set, has only a few user-defined inputs, and has a classical (polynomial) scaling with respect to the number of degrees of freedom (of the vibronic model), resulting in a favorable computational cost. In benchmark applications to small models and molecules, the VECC method provides accurate results compared to multi-configurational time-dependent Hartree calculations when predicting short-time dynamical properties (i.e., photo-electron/UV–VIS absorption spectra) for non-adiabatic vibronic models. To illustrate the capabilities, the VECC method is also successfully applied to a large vibronic model for hexahelicene with 14 electronic states and 63 normal modes, developed in the group by Aranda and Santoro [J. Chem. Theory Comput. 17, 1691, (2021)].
Numerical study of positive temperature coefficient heating on the lithium-ion battery at low temperature
Authors: Mu Mingfei , Sui Pengxiao , Kou Guiyue , Ding Bin , Han Zilin , Sun Kai , Zhang Qiang , Hu Xiaodong
Published: March 2024

The performance of lithium-ion batteries may decline at cold temperatures, leading to reduced capacity and electrolyte freezing. To ensure proper operation of energy storage stations in cold regions, heating methods must be designed to maintain batteries at 283.15 K while limiting the temperature difference to less than 5 K. Theoretical analysis and simulation of a battery heating method were conducted using a 22 Ah lithium iron phosphate battery as the research object at 253.15 K. A heating method was designed using Positive Temperature Coefficient (PTC) aluminum plate heaters. Results showed that under the condition of an ambient temperature of 253.15 K and a discharge rate of 1 C, five 120 W PTCs could increase the peak temperature to 283.46 K at 1000 s. The heating method was further optimized by changing the PTC number (2, 3, and 4) and size (corresponding to 120%, 100%, 80%, and 60% of the lithium-ion battery dimensions), and it was found that by using 3 PTC heating plates with 80% size, the maximum temperature could be increased to 289.85 K and the average temperature difference was 4.82 K at 1000 s, meeting the needs of battery operation. The heating method was shown to be effective in rapidly increasing the battery temperature at lower ambient temperatures (243.15, 253.15, and 263.15 K), increasing the rate of temperature increase by 32.4% at 243.15 vs 253.15 K and 45.2% at 263.15 K.
Numerical investigation of the aerodynamic performance and loss mechanism in a low bypass ratio variable cycle engine fan
Authors: Fan Zhonggang , Yang Chen , Ba Dun , Zhang Min , Du Juan
Published: March 2024

The aerodynamic performance of the variable cycle engine fan changes sharply during mode transition. Investigating the variations of flow structure and understanding the loss mechanism are helpful in providing guidance for the fan design. Three-dimensional models of single bypass and double bypass compression systems are established, and static pressure is applied at the bypass stream outlet to simulate the opening of the mode selection valve. The characteristic band of variable cycle engine fan is obtained by gradually increasing the bypass stream pressure while maintaining specific values for the core stream pressure. Results show that the overall performance of the double bypass configuration, without bypass recirculation, is almost identical to that of the conventional single bypass configuration during the throttling process. With the increase in bypass pressure, the shock wave and the trajectory of tip leakage vortex gradually move forward, thereby increasing the blockage region induced by the interaction between the shock and tip leakage vortex. In addition, the performance of fan with reverse flow is also calculated. The recirculation causes the operating point to move closer to the stability limit, reducing the isentropic efficiency. Additionally, the recirculation changes the radial distribution of axial velocity and total pressure, leading to inlet distortion in the core driven fan stage. Furthermore, the loss mechanism is clarified by modeling the splitter and conducting entropy generation analysis. The sharp expansion of bypass stream could cause severe flow separation, and reducing the curvature of casing can effectively suppress the viscous shear loss.
Investigations on affinity law under gas–liquid conditions in multistage radial and mixed-flow multiphase pumps
Authors: Chang Liang , Yang Chenyu , Su Xiaobin , Dai Xiaoyu , Xu Qiang , Guo Liejin
Published: March 2024

Affinity laws have been widely used in pump design and simulation under high-temperature and corrosive conditions. By applying such laws, it is possible to shorten development cycles and reduce test costs. However, current applications of affinity laws are still limited to liquid conditions. In this paper, expressions for affinity laws and their applicability are investigated for multistage radial and mixed-flow multiphase pumps under gas–liquid conditions. A high-pressure (30 MPa) gas–liquid experimental platform is constructed, and three-stage and 25-stage radial pumps and a 15-stage mixed-flow pump are investigated, with specific speeds of 107 and 216. With gas compressibility taken into account, the gas–liquid two-phase flow rate, head, and power, and the corresponding dimensionless hydraulic coefficients, are defined for multiphase pumps. The deterioration of gas–liquid pressurization performance is found to be divided into three processes with different dynamic mechanisms, corresponding to three flow patterns. The inlet gas volume fraction of pump is used to judge dynamic similarity. At the same inlet gas volume fractions λ1 = λ2, when the gas–liquid flows in two pumps have the same flow pattern, dynamic similarity will be satisfied. The affinity law that is established shows good applicability to the three-stage radial multiphase pump, with goodness of fit R2 larger than 0.9 for the two-phase Ψm–Φm and Πm–Φm performance curves. Finally, experimental results indicate that the affinity law also has good applicability to multiphase pumps with different stage numbers and blade structures under gas–liquid conditions.
Effect of dust size distribution and nonadiabatic charge variation on dispersion relation for linear waves in inhomogeneous complex plasmas
Authors: Fu Jun , Zhang Liping , Zhang Meilin
Published: March 2024

This paper explores linear waves’ instability in nonuniform complex plasmas with dust size distribution and non-adiabatic dust charge fluctuation. For this purpose, the dispersion relation is obtained with the aid of linearizing the hydrodynamic equations governing the properties of linear waves. The contribution of physical parameters such as inhomogeneity, nonadiabatic dust charge fluctuation, and dust size distribution to the features of dust acoustic waves is examined at great length. The numerical results show that the present research results are very important in the phenomenon of space astrophysical and experimental plasmas.
Terahertz super-radiance from picosecond electron bunches moving through a micro-undulator
Authors: Ginzburg N. S. , Vilkov M. N. , Malkin A. M. , Sergeev A. S. , Bandurkin I. V. , Fedotov A. E. , Peskov N. Yu. , Loginov P. V.
Published: March 2024

We suggest using emission from the photoinjector-formed electron bunches moving through micro-undulators for generation of powerful super-radiant pulses in the terahertz/far infrared frequency range. Within the time-domain quasi-optical approach, we demonstrate the spatial coherence of emission with narrow angular spectrum from the electron bunches with transverse size limited by the Fresnel parameter NF ∼ 1, when the diffraction effects together with slippage provide synchronization of radiation from the entire volume of the extended bunch. For picosecond-duration, 5 MeV, 250 pC electron bunches, and a micro-undulator with a period of 3 mm, the peak power of 15 THz SR pulses can be about of 20 MW.
Cu-doping induced tuning of magnetic properties and phase transformation in MnBi alloys
Authors: Yang Yang , Xu Hui Yu , Da Lu Shun , Xiang Zhen , Chen Lin Feng , Li Cheng Yu , Truong Nguyen Xuan , Lu Wei
Published: March 2024

This study investigates the effect of Cu doping on the magnetic properties of MnBi alloy at sub-ambient temperatures. The Curie temperatures (Tc) were observed at 175.2 and 161.6 K for Mn52Bi45Cu3 and Mn51Bi45Cu4 alloys, respectively. The Mn55Bi45 sample demonstrates a notable saturation magnetization (Ms) of 72 emu/g, reaching 90% of the theoretical value, indicating the successful synthesis of high-purity ferromagnetic low-temperature phase MnBi. Compared to Mn55Bi45, all Cu-doped samples exhibit higher coercivity (Hc) within the temperature range of 10–200 K. In particular, the sample with 4 at. % Cu exhibits an Hc of 7.4 kOe at 10 K, which is 37 times higher than that of the MnBi sample (0.2 kOe), and it remains significantly higher than that of the 0–3 at. % Cu-doped samples, even at 200 K. Further details of this investigation are presented in this paper.
Review of Scientific Instruments New Products
Authors: Mandelis Andreas
Published: March 2024

In order to supplement manufacturers’ information, this department will welcome the submission by our readers of brief communications reporting measurements on the physical properties of materials which supersede earlier data or suggest new research applications.
Design of continuous repeater power transmission coil for wireless power transfer system for EVs with consideration of vehicle deviation
Authors: Saito A. , Oishi Y. , Miyahara S. , Sato F. , Matsuki H.
Published: March 2024

In recent years, EVs have become increasingly popular around the world, and research on wireless power supply technology for EV driving has progressed accordingly. In order to realize this wireless power transfer system for EVs on a real scale, it is necessary to lengthen the power transfer section per power transfer unit and to secure a sufficient power transfer section with a small number of power transfer units as a whole. To solve this problem, the single coil method, in which one coil is lengthened, has been proposed. However, as the coil length increases, resistance loss increases and efficiency decreases. Therefore, a repeater coil system has been proposed. In this in-transit power-feeding system, it is necessary to consider transient phenomena when the EV to be fed deviates from the feeding lane. Therefore, we propose a new repeater coil configuration on the transmission side that assumes a no-load condition. In this study, a new repeater coil system combining rectangular coils and orthogonal coils is proposed, which enables stable feeding of power to EVs by rectangular coils and response to transient phenomena. A comparison was also made with the single coil method that has been studied previously.
Green ammonia can be a clean energy source
Authors: Kramer David
Published: March 2024

The world’s second-most-produced chemical is poised to grow beyond its use in fertilizers to become an efficient medium to carry green hydrogen across the oceans.
Absolute energy levels of liquid water from many-body perturbation theory with effective vertex corrections
Authors: Tal Alexey , Bischoff Thomas , Pasquarello Alfredo
Published: March 2024

We demonstrate the importance of addressing the Γ vertex and thus going beyond theGWapproximation for achieving the energy levels of liquid water in many-body perturbation theory. In particular, we consider an effective vertex function in both the polarizability and the self-energy, which does not produce any computational overhead compared with theGWapproximation. We yield the band gap, the ionization potential, and the electron affinity in good agreement with experiment and with a hybrid functional description. The achieved electronic structure and dielectric screening further lead to a good description of the optical absorption spectrum, as obtained through the solution of the Bethe–Salpeter equation. In particular, the experimental peak position of the exciton is accurately reproduced.
Torsional force microscopy of van der Waals moirés and atomic lattices
Authors: Pendharkar Mihir , Tran Steven J. , Zaborski Gregory , Finney Joe , Sharpe Aaron L. , Kamat Rupini V. , Kalantre Sandesh S. , Hocking Marisa , Bittner Nathan J. , Watanabe Kenji , Taniguchi Takashi , Pittenger Bede , Newcomb Christina J. , Kastner Marc A. , Mannix Andrew J. , Goldhaber-Gordon David
Published: March 2024

In a stack of atomically thin van der Waals layers, introducing interlayer twist creates a moiré superlattice whose period is a function of twist angle. Changes in that twist angle of even hundredths of a degree can dramatically transform the system’s electronic properties. Setting a precise and uniform twist angle for a stack remains difficult; hence, determining that twist angle and mapping its spatial variation is very important. Techniques have emerged to do this by imaging the moiré, but most of these require sophisticated infrastructure, time-consuming sample preparation beyond stack synthesis, or both. In this work, we show that torsional force microscopy (TFM), a scanning probe technique sensitive to dynamic friction, can reveal surface and shallow subsurface structure of van der Waals stacks on multiple length scales: the moirés formed between bi-layers of graphene and between graphene and hexagonal boron nitride (hBN) and also the atomic crystal lattices of graphene and hBN. In TFM, torsional motion of an Atomic Force Microscope (AFM) cantilever is monitored as it is actively driven at a torsional resonance while a feedback loop maintains contact at a set force with the sample surface. TFM works at room temperature in air, with no need for an electrical bias between the tip and the sample, making it applicable to a wide array of samples. It should enable determination of precise structural information including twist angles and strain in moiré superlattices and crystallographic orientation of van der Waals flakes to support predictable moiré heterostructure fabrication.
Genome copy number predicts extreme evolutionary rate variation in plant mitochondrial DNA
Authors: Zwonitzer Kendra D. , Tressel Lydia G. , Wu Zhiqiang , Kan Shenglong , Broz Amanda K. , Mower Jeffrey P. , Ruhlman Tracey A. , Jansen Robert K. , Sloan Daniel B. , Havird Justin C.
Published: March 2024

Nuclear and organellar genomes can evolve at vastly different rates despite occupying the same cell. In most bilaterian animals, mitochondrial DNA (mtDNA) evolves faster than nuclear DNA, whereas this trend is generally reversed in plants. However, in some exceptional angiosperm clades, mtDNA substitution rates have increased up to 5,000-fold compared with closely related lineages. The mechanisms responsible for this acceleration are generally unknown. Because plants rely on homologous recombination to repair mtDNA damage, we hypothesized that mtDNA copy numbers may predict evolutionary rates, as lower copy numbers may provide fewer templates for such repair mechanisms. In support of this hypothesis, we found that copy number explains 47% of the variation in synonymous substitution rates of mtDNA across 60 diverse seed plant species representing ~300 million years of evolution. Copy number was also negatively correlated with mitogenome size, which may be a cause or consequence of mutation rate variation. Both relationships were unique to mtDNA and not observed in plastid DNA. These results suggest that homologous recombinational repair plays a role in driving mtDNA substitution rates in plants and may explain variation in mtDNA evolution more broadly across eukaryotes. Our findings also contribute to broader questions about the relationships between mutation rates, genome size, selection efficiency, and the drift-barrier hypothesis.
Tertiary folds of the SL5 RNA from the 5′ proximal region of SARS-CoV-2 and related coronaviruses
Authors: Kretsch Rachael C. , Xu Lily , Zheludev Ivan N. , Zhou Xueting , Huang Rui , Nye Grace , Li Shanshan , Zhang Kaiming , Chiu Wah , Das Rhiju
Published: March 2024

Coronavirus genomes sequester their start codons within stem-loop 5 (SL5), a structured, 5′ genomic RNA element. In most alpha- and betacoronaviruses, the secondary structure of SL5 is predicted to contain a four-way junction of helical stems, some of which are capped with UUYYGU hexaloops. Here, using cryogenic electron microscopy (cryo-EM) and computational modeling with biochemically determined secondary structures, we present three-dimensional structures of SL5 from six coronaviruses. The SL5 domain of betacoronavirus severe-acute-respiratory-syndrome-related coronavirus 2 (SARS-CoV-2), resolved at 4.7 Å resolution, exhibits a T-shaped structure, with its UUYYGU hexaloops at opposing ends of a coaxial stack, the T’s “arms.” Further analysis of SL5 domains from SARS-CoV-1 and MERS (7.1 and 6.4 to 6.9 Å resolution, respectively) indicate that the junction geometry and inter-hexaloop distances are conserved features across these human-infecting betacoronaviruses. The MERS SL5 domain displays an additional tertiary interaction, which is also observed in the non-human-infecting betacoronavirus BtCoV-HKU5 (5.9 to 8.0 Å resolution). SL5s from human-infecting alphacoronaviruses, HCoV-229E and HCoV-NL63 (6.5 and 8.4 to 9.0 Å resolution, respectively), exhibit the same coaxial stacks, including the UUYYGU-capped arms, but with a phylogenetically distinct crossing angle, an X-shape. As such, all SL5 domains studied herein fold into stable tertiary structures with cross-genus similarities and notable differences, with implications for potential protein-binding modes and therapeutic targets.
The mass gap in five dimensional Einstein–Gauss–Bonnet black holes: a geometrical explanation
Authors: Hansraj C , Goswami R , Maharaj S D
Published: March 2024

It is well known that, unlike in higher dimensional general relativity (GR), we cannot have a black hole with an arbitrarily small mass in five dimensional Einstein–Gauss–Bonnet gravity. When we study the dynamical black hole formation via the radiation collapse in the radiating Boulware–Deser spacetime in five dimensions, the central zero mass singularity is weak, conical and naked, and the horizon forms only when a finite amount of matter, that depends on the coupling constant of the Gauss–Bonnet term, falls into the central singularity. To understand this phenomenon transparently and geometrically, we study the radiating Boulware–Deser spacetime in five dimensions using a 1+1+3 spacetime decomposition, for the first time. We find that the geometric and thermodynamic quantities can be expressed in terms of the gravitational mass and the Gauss–Bonnet (GB) parameter and separate each of them into their Gauss–Bonnet and matter parts. Drawing comparisons with five dimensional GR at every step, we explicitly show how the mass gap arises for a general mass function M(v) and what functions for M(v) make certain geometrical quantities well defined at the central singularity. We show in the case of self-similar radiation collapse in the modified theory, the central singularity is not a sink for timelike geodesics and is extendable. This clearly demonstrates how the GB invariant affects the nature of the final state of a continual collapse in this modified theory.