bluuebunny/crossref_metadata_2025 huggingface dataset:
Cuckoo search algorithm for the evacuation strategy of people in flash floods using a spatiotemporal conditions weight
Authors: Spyrou Evangelos D. , Anagnostopoulou Afroditi , Kappatos Vassilios
Published: October 2023

Natural disasters are responsible for the destruction of infrastructures, detrimental environmental effects as well as the loss of lives in places around the world. In particular, flash floods can be disastrous both for habitants and the environment. Flooding pollutants contaminate water and corresponding negative impacts appeared on flora, fauna and people. In addition, space in cities is becoming lesser year-by-year and rivers disappeared due to anarchic buildings in urban areas. This results in flooding as the water cannot find another route to escape other than the streets of the area. In Attica region of Greece, flooding incidents occurred after flash storms and even losses of lives have been reported. This brings up the issue of civil protection and immediate evacuation of people in case of sudden floods in populated urban areas. The first responders need to act as fast as possible to avoid losses of lives and to minimize the negative environmental impacts. In this paper, we suggest a bio-inspired algorithm based on Cuckoo Search (CS) to find the best route between hazardous places based on a weighting metric that identifies the potential danger posed by flooding. Simulation experiments were conducted to evaluate the proposed approach for improving the overall effectiveness of the evacuation procedures implemented in flood-prone areas.
Biodiesel production from edible and non-edible biomasses and its characterization
Authors: Emmanouilidou Elissavet , Lazaridou Anastasia , Mitkidou Sophia , Kokkinos Nikolaos C.
Published: October 2023

Biodiesel is considered one of the most viable renewable alternatives to its petroleum-derived counterpart. It can be produced from various sources, mainly via homogeneously alkali-catalyzed transesterification. Nevertheless, as the demand for edible oils grew for food and fuel, non-edible oils emerged as a more appealing choice for producing biodiesel. Waste cooking oils (WCOs) comprise an alternative and low-cost feedstock that are produced in vast quantities and can be used for biodiesel production. This study compares biodiesel properties produced by an uncooked sunflower oil obtained from a local bio-industry and a WCO sample collected from a fast food shop. Results showed that most biodiesel samples’ properties in both cases met the EN 14214 specifications. GC-MS chromatographs were similar in terms of fatty acid methyl esters (FAMEs) composition. However, oxidation stability for both biodiesel samples and viscosity for the WCO biodiesel sample were out of specifications. Further investigation is required to improve biodiesel properties and optimize production conditions.
Microfluidic technology for macro systems: Removal of textile dyes from wastewater in a microreactor
Authors: Svetozarević Arsović Milica , Šekuljica Nataša , Dajić Ana , Mihajlović Marina , Marković Maja , Knežević-Jugović Zorica , Mijin Dušan
Published: October 2023

Wastewater from textile industry contains considerable amount of dissolved dye that can trigger environmental issues if is not treated properly. Numerous methods have been developed to degrade recalcitrant pollutants safely and utterly. Among them, enzymatic treatment of wastewater is gaining attention due to the enzyme’s specificity, easier manipulation, and generation of less toxic by-products. Still, the cost of enzymatic systems is the main limitation keeping the biocatalysts at lab-scale. Alternative solution for reducing the cost of enzymatic reaction systems is the use of microfluidic systems, which contribute to better mixing, process intensification and cleaner production. In this study, implementation of horseradish peroxidase for removal of the textile dye Acid Violet 109 is performed in a microfluidic reactor. The microreactor consists of three plunger pump units, two mixers and PTFE tube. The process parameters: residence time, dye, hydrogen peroxide, enzyme activity, the reactors’ diameter and length were optimized. Under the optimal process conditions: 30 mg/L dye concentration, 0.8 U/mL horseradish peroxidase activity, 0.1 mM hydrogen peroxide, 0.25 mm reactor’s diameter, 97,3 % removal was achieved at residence time of 6 min. The results from this study show that enzymatic microfluidic reactors are a convenient technology for dye removal.
Fault detection of air quality measurements using artificial intelligence
Authors: Evagelopoulos Vasilis , Charisiou Nikolaos D. , Begou Paraskevi
Published: October 2023

In this work we use Artificial Intelligence (AI) for the detection of faults in air quality measurements. This is crucial in large air quality monitoring networks in particular were fault detection can be a complex and time consuming process. The proposed methodology encompasses several essential steps in anomaly detection. Data preprocessing ensures the quality and relevance of the data by applying techniques like data cleaning, outlier removal, and feature selection. The Isolation Forest model is trained using the pre-processed data, and appropriate hyperparameters are determined through cross-validation. Anomaly detection is performed using the trained model, allowing the identification of abnormal events or instances. The visualization of anomalies provides a clear representation of abnormal patterns, facilitating the interpretation and understanding of air quality data. The proposed methodology can help environmental agencies, researchers, and policymakers in identifying abnormal air quality events, enhancing the accuracy of monitoring systems, and facilitating timely interventions. This methodology can be applied to other industries also, to improve operations and reduce risk.
Sustainable Urban Mobility (SUM), a bibliometric analysis with examples from Budapest and Vienna
Authors: Qasseer Ola , Szalkai Gábor
Published: October 2023

Sustainable Urban Mobility (SUM) is a relatively modern term that started to be used in literature after the beginning of the 21st century and has recently gained significant popularity. In this paper we analyze the main aspects of SUM term, its development, and its main concepts and keywords. We also analyze the main aspects of SUM in Budapest and Vienna and compare them. A bibliometric analysis is achieved on the extracted literature using VOSviewer and Excel software. Analyzing the two case studies is achieved through revising the published plans of SUM in both cities then comparing them. SUM term reached its peak around 2020. The main aspects which accompanied this term are related to sustainable modes, planning, and policies. Budapest and Vienna cities are heading to be more sustainable cities. However, additional steps need to be taken in this regard. Analyzing the situation in the two case studies, depending on the results of the bibliometric analysis and comparing them will help in understanding to which level they represent successful examples of sustainability in Europe. In addition to proposing some useful points to develop the process of producing SUM plans to provide a more balanced and livable urban environment.
Todesfälle in einem Wurf französischer Bulldoggen
Welpen im Zusammenhang mit dem caninen Herpesvirus 1
Authors: Schmid Sarah , Sievert Maren , Wehrend Axel
Published: October 2023

Dieser Fallbericht beschreibt das Auftreten einer caninen Herpesvirus 1-Infektion
bei einem Wurf französischer Bulldogen. Zudem wurde die Literatur zum
Thema infektiöses Welpensterben zusammengefasst. Zwei neonatale Welpen
wurden aufgrund von Dyspnoe vorgestellt. Im Verlauf der Nacht entwickelte einer
der Welpen Diarrhoe sowie ein hochgradig gestörtes Allgemeinbefinden und
wurde am nächsten Tag euthanasiert. Der zweite Welpe wurde 6 Stunden
später ebenfalls mit hochgradig gestörtem Allgemeinbefinden
euthanasiert. In der Sektion konnten Hinweise auf eine Infektion mit dem caninen
Herpesvirus gefunden werden. Dies bestätigte sich in der virologischen
Untersuchung. Dieser Fallbericht zeigt, dass auch in Deutschland die Infektion
mit dem caninen Herpesvirus als Todesursache von neugeborenen Welpen beachtet
werden muss.
Listening, reading, writing – which method leads to the best
learning outcome?
Authors: Güldenpfennig Janine , Bartel Alexander , Arlt Sebastian
Published: October 2023

Objective Innovative teaching strategies such as case-based learning and
hands-on training are more and more integrated into undergraduate veterinary
teaching. Nevertheless, it can be assumed that lectures still play an important
role in many vet schools. Nowadays, however, lectures are questioned to be
motivating and engaging enough for a long-lasting learning retention. In this
context, we compared acceptance and learning outcome of the teaching methods
reading, writing, and listening to a presentation.

Material and methods In structured settings based on a cross-over design,
151 students in their fifth year attending a 2-weeks clinical rotation at the
Clinic for Animal Reproduction were asked to read papers, listen to a
presentation by a lecturer, and to write a summary in group work. Each task
dealt with 1 of 3 topics from the field of animal reproduction. A week later,
the students were asked to complete a multiple-choice test and an evaluation
form. The test contained questions about each of the covered topics as well as a
fourth topic, which was not taught in context of this project to assess the
students’ prior knowledge.

Results The results revealed that writing a summary in group work led to
the best learning outcome, but it cannot be ruled out that learning success may
have depended to a large extent on group work. Furthermore, the results did not
differ significantly from the second-best teaching method listening to a
presentation. The teaching method students preferred most was the lecture,
followed by reading papers and writing a summary.

Conclusions We conclude that presentations by lecturers are still an
important teaching method but can be complemented by writing tasks, which may be
used in specific settings as a possible way to improve learning outcome in
veterinary education.

Conclusion for practice Our project supports the assumption that more
active, student-centered learning approaches such as writing summaries can lead
to more engagement and a better learning retention. In addition, training
writing skills is important because clinical reports and other written
communication are relevant parts of daily veterinary routine.
Diagnostischer Nutzen des Anti-Müller-Hormons in der
Kleintierpraxis
Authors: Walter Beate
Published: October 2023

Das Anti-Müller-Hormon ist ein Glykoprotein, das bei männlichen
Individuen von den Sertolizellen und bei weiblichen von den Granulosazellen
sezerniert wird. Bei Hunden und Katzen wurde es erstmals 2011 im Blutserum
bestimmt. Inzwischen konnten mehrere Studien die klinischen Anwendungen der
Anti-Müller-Hormon-Bestimmung als Parameter in der endokrinen Diagnostik
aufzeigen. Dieser Übersichtsartikel fasst den momentanen Wissensstand
über die klinischen Anwendungen der
Anti-Müller-Hormon-Bestimmung in der Kleintierpraxis zusammen und
beschreibt mögliche zukünftige diagnostische
Ansätze.
Bildgebende Diagnostik im Rahmen der Trächtigkeit beim
Hund
Authors: Zelck Alexandra B. , Köhler Claudia , Kiefer Ingmar
Published: October 2023

Im Rahmen der Trächtigkeitsüberwachung des Hundes spielen die
bildgebenden Verfahren eine entscheidende Rolle. Die Sonografie hat sich zu der
Modalität der Wahl bei der Trächtigkeitsdiagnose etabliert und
bietet die Möglichkeit, eine Trächtigkeit bereits ab dem
17.–20. Tag nach dem LH-Peak nachzuweisen. Weiterhin ermöglicht
sie eine Beurteilung der fetalen Vitalität und Entwicklung, die
Darstellung von fetalen Missbildungen und die frühzeitige Erkennung von
fetalem Stress. Hierbei kann auch die Doppler-Sonografie unterstützend
eingesetzt werden. Die Bestimmung des Wurfzeitpunktes kann über die
Beurteilung des fetalen Entwicklungsstandes und über Messungen der
fetalen und extrafetalen Strukturen erfolgen. Die Röntgendiagnostik
ermöglicht einen Trächtigkeitsnachweis ca. ab dem 43. Tag nach
dem LH-Peak und bietet eine Beurteilung der Wurfgröße und der
Größe der einzelnen Feten. Bei Geburtsstörungen und
Dystokiepatienten liefern beide Verfahren komplementär schnelle Aussagen
zu verschiedenen Fragestellungen, die die Entscheidung für einen
operativen Eingriff unterstützen und das Management von Hündin
und Welpen bestimmen.
Glycemic Variability and the Risk of Diabetic Peripheral Neuropathy:
A Meta-Analysis
Authors: Song Ying , Zhang Haiyan , Sun Ju , Long Ying , Zhang Kaixiang , Yin Qian , Duan Xiaorong
Published: October 2023

Glycemic variability (GV) has been related to complications in patients with
diabetes. The aim of the systematic review and meta-analysis was to investigate
whether GV is also associated with the incidence of diabetic peripheral
neuropathy (DPN). A systematic search of Medline, Web of Science, Embase, and
Cochrane Library database was conducted to identify relevant observational
studies with longitudinal follow-up. The Newcastle-Ottawa Scale was used for
study quality evaluation. A random-effects model was utilized to pool the
results, accounting for heterogeneity. Ten observational studies including 72
565 patients with diabetes were included. The quality score was 8–9,
indicating generally good quality of the included studies. With a mean follow-up
duration of 7.1 years, 11 532 patients (15.9%) were diagnosed as DPN.
Compared to patients with low GV, patients with high GV were associated with an
increased risk incidence of DPN (risk ratio: 1.51, 95% confidence
interval: 1.23 to 1.85, p<0.001; I2=78%). In addition,
subgroup analysis showed consistent results in patients with type 1 and type 2
diabetes, and in studies evaluating the short-term and long-term GV (p for
subgroup difference=0.82 and 0.53). Finally, results of subgroup
analysis also suggested that the association between GV and risk of DPN were not
significantly affected by study design, follow-up durations, diagnostic methods
for DPN, adjustment of mean glycated hemoglobin A1c, or study quality scores (p
for subgroup difference all>0.05). A high GV may be associated with an
increased incidence of DPN.
Contrast-enhanced ultrasound reveals perfusion differences between benign lipoma and semi-malignant atypical lipomatous tumors: A prospective clinical study
Authors: Mick Paul , Seeberger Antonia , Renkawitz Tobias , Lehner Burkhard , Hariri Mustafa , Fischer Christian , Doll Julian
Published: October 2023

Purpose Soft tissue tumors (STT) are difficult to diagnose accurately, and distinguishing between benign and malignant tumors is challenging. Lipoma is the most common STT, while atypical lipomatous tumors (ALT) can dedifferentiate into malignant lipomatous tumors like grade 1 liposarcoma and require more radical therapy. This study aims to investigate the potential of contrast-enhanced ultrasound (CEUS) to differentiate between lipoma and ALT based on tumor perfusion.

Materials and Methods We prospectively examined 52 patients who were scheduled for biopsy for suspected lipoma or ALT. The CEUS examination was performed using SonoVue as a contrast agent to quantify tumor perfusion using VueBox V7.1 software. Peak enhancement (PE), rise time (RT), wash-in perfusion index (WiPI), and wash-out rate (WoR) were used to assess contrast enhancement inside the STT.

Results Among 50 tumors examined, 30 were lipomas, and 20 were ALTs. We found significant differences in perfusion between lipomas and ALTs (PE: 49.22 ± 45.75 a.u. vs. 165.67 ± 174.80; RT: 23.86 ± 20.47s vs. 10.72 ± 5.34 s; WiPI: 33.06 ± 29.94 dB vs. 107.21 ± 112.43 dB; WoR: 2.44 ± 3.70 dB/s vs. 12.75 ± 15.80 dB/s; p<.001). ROC analysis of PE resulted in a diagnostic accuracy of 74% for the detection of an ALT, and 77% for the detection of a lipoma.

Conclusion CEUS may enhance the differential diagnosis of benign lipomas and ALTs, with ALTs showing higher levels of perfusion. If larger prospective studies confirm these findings, CEUS could enhance diagnostic accuracy, guide surgical planning, and potentially reduce unnecessary treatments for patients presenting with ambiguous lipomatous tumors like lipoma or ALT.
Thyroid Diseases and Intestinal Microbiome
Authors: Legakis Ioannis , Chrousos George P. , Chatzipanagiotou Stylianos
Published: October 2023

The human microbiome plays an integral role in health. In particular, it is
important for the development, differentiation, and maturation of the immune
system, 70% of which resides in the intestinal mucosa. Microbiome
studies conducted to date have revealed an association between disturbances in
the microbiota (dysbiosis) and various pathological disorders, including changes
in host immune status. Autoimmune thyroid diseases are one of the most common
organ-specific autoimmune disorders, with a worldwide prevalence higher than
5%. The predominant autoimmune thyroid diseases are Hashimoto’s
thyroiditis and Grave’s disease. Several factors, such as genetic and
environmental ones, have been studied. In accordance with recent studies, it is
assumed that the gut microbiome might play a significant role in triggering
autoimmune diseases of the thyroid gland. However, the exact etiology has not
yet been elucidated. The present review aims to describe the work carried out so
far regarding the role of gut microflora in the pathogenesis of autoimmune
thyroid diseases and its involvement in the appearance of benign nodules and
papillary thyroid cancer. It appears that future work is needed to elucidate
more precisely the mechanism for gut microbiota involvement in the development
of autoimmune thyroid diseases.
Solvent Selection in the Detritylation Reaction for the Solid-Phase Synthesis of Oligonucleotides
Authors: Sanghvi Yogesh S. , Yan Hongbin , Li Quanjian
Published: October 2023

This study examined the choice of solvent in the detritylation reaction for solid-phase oligonucleotide synthesis. In addition to being chemically inert under detritylation conditions, such a solvent should not bind with acid used in this reaction. These considerations explained the only two choices of solvent currently used in the detritylation reaction: dichloromethane and toluene. Other solvents, such as ethyl acetate, acetonitrile, THF, and nitromethane are shown by NMR spectroscopy to bind with trichloroacetic acid. Therefore, these are undesirable solvents for the detritylation reaction, confirmed by solid-phase synthesis experiments.
Hyperbolic reduction of the Weyl–Lanczos equations
Authors: Normann M.
Published: October 2023

We provide a new framework to find the Lanczos potential of the Weyl tensor in terms of two symmetric and spatial fields. We show that given any space time with the Einstein field equations coupled to a general matter source, a Lanczos potential can be identified by solving a symmetric hyperbolic system of evolution equations.
Autoregressive transformers for data-driven spatiotemporal learning of turbulent flows
Authors: Patil Aakash , Viquerat Jonathan , Hachem Elie
Published: October 2023

A convolutional encoder–decoder-based transformer model is proposed for autoregressively training on spatiotemporal data of turbulent flows. The prediction of future fluid flow fields is based on the previously predicted fluid flow field to ensure long-term predictions without diverging. A combination of convolutional neural networks and transformer architecture is utilized to handle both the spatial and temporal dimensions of the data. To assess the performance of the model, a priori assessments are conducted, and significant agreements are found with the ground truth data. The a posteriori predictions, which are generated after a considerable number of simulation steps, exhibit predicted variances. The autoregressive training and prediction of a posteriori states are deemed crucial steps toward the development of more complex data-driven turbulence models and simulations. The highly nonlinear and chaotic dynamics of turbulent flows can be handled by the proposed model, and accurate predictions over long time horizons can be generated. Overall, the potential of using deep learning techniques to improve the accuracy and efficiency of turbulence modeling and simulation is demonstrated by this approach. The proposed model can be further optimized and extended to incorporate additional physics and boundary conditions, paving the way for more realistic simulations of complex fluid dynamics.
In situ synthesis of C–SiO2 enhanced Pd nanoparticles for catalytic dehydrogenation of formic acid
Authors: Li Xia , Deng Min , Cao Tingting , Ma Jun , Geng Shuo , Ren Yuan , Yao Mengqin , Liu Fei , Dong Yonggang
Published: October 2023

Formic acid (FA, HCOOH), as a liquid chemical hydrogen storage carrier with low cost, high hydrogen content, and convenient storage and transportation, has attracted extensive attention. Pd-based catalysts for hydrogen production from FA are easy to aggregate and deactivate in the reaction process, which hinders the further development of FA as a hydrogen storage carrier. Therefore, the exploitation of carriers with simple preparation methods and excellent performance can effectively improve the catalytic activity of Pd-based catalysts. Porous carbon and SiO2 have been widely used for their unique structural properties, and the preparation of composite carriers by combining the advantages of both is a current research hotspot. Herein, this work synthesized C–SiO2 for the deposition of Pd nanoparticles by a one-step method, and the obtained Pd/C–SiO2 exhibits a superior FA dehydrogenation activity with a turnover frequency value of 1278 h−1 and a favorable stability with only a slight decrease in activity after five cycles.
A practical stress-based test method for evaluating reversible stress limit for critical current degradation in rare-earth barium copper oxide (REBCO) tapes
Authors: Shin Hyung-Seop , Velasco Madelene , Diaz Mark Angelo
Published: October 2023

The superior electromechanical properties of second-generation high-temperature superconducting rare-earth barium copper oxide (REBCO) coated conductor tapes make them viable candidates for high magnetic field applications. To characterize their electromechanical properties (EMPs) under operating conditions, the critical current degradation behavior of the REBCO tapes should be evaluated. Conventional evaluation methods for EMPs usually rely on a strain-based test method that utilizes an extensometer to measure the deformation induced on the coated conductor tape. This study aims to establish a practical stress-based test method that determines the reversible stress limit for critical current (Ic) degradation in REBCO tapes without using extensometers under uniaxial tension. For an efficient test procedure, Ic measurements were initially performed with broad stress intervals and then changed to narrow stress intervals before the critical current degraded irreversibly. Four commercially available REBCO tape samples were used to validate the reliability of the proposed stress-based test method. It was then assessed by comparing them with those obtained using the conventional strain-based test method. Statistical estimations were used to determine the reproducibility of the results. These results provide a basis for an international round-robin test guideline to establish a test method for measuring the electromechanical properties of high-temperature superconducting tapes at cryogenic temperatures.
Evolutionary dynamics of N-player sender-receiver game in networks with community structure
Authors: Li Wenbo , Zhu Yuying , Xia Chengyi
Published: October 2023

Network typology largely affects the evolutionary dynamics of collective behaviors in many real-world complex systems. As a conventional transmission model, the sender–receiver game paves the way to explore the evolution of honest signals between senders and receivers. In practice, the utilities of an agent often depend not only on pairwise interactions, but also on the group influence of players around them, and thus there is an urgent need for deeper theoretical modeling and investigations on individuals’ non-pairwise interactions. Considering the underlying evolutionary game dynamics and multiple community network structures, we explore the evolution of honest behaviors by extending the sender–receiver game to multiple communities. With the new dynamical model of the multi-community system, we perform a stability analysis of the system equilibrium state. Our results reveal the condition to promote the evolution of honest behaviors and provide an effective method for enhancing collaboration behaviors in distributed complex systems. Current results help us to deeply understand how collective decision-making behaviors evolve, influenced by the spread of true information and misinformation in large dynamic systems.
Improving cement production process with data-augmented sequence to sequence-Wasserstein generative adversarial networks model for accurate prediction of f-CaO
Authors: Zhang Ying , Liu Jinbo , Dang Hui , Zhang Yifu , Huang Gaolu , Jiao Junze , Hao Xiaochen
Published: October 2023

This paper proposes a method to address the issue of insufficient capture of temporal dependencies in cement production processes, which is based on a data-augmented Seq2Seq-WGAN (Sequence to Sequence-Wasserstein Generate Adversarial Network) model. Considering the existence of various temporal scales in cement production processes, we use WGAN to generate a large amount of f-CaO label data and employ Seq2Seq to solve the problem of unequal length input–output sequences. We use the unlabeled relevant variable data as the input to the encoder of the Seq2Seq-WGAN model and use the generated labels as the input to the decoder, thus fully exploring the temporal dependency relationships between input and output variables. We use the hidden vector containing the temporal characteristics of cement produced by the encoder as the initial state of the gate recurrent unit in the decoder to achieve accurate prediction of key points and continuous time. The experimental results show that the Seq2Seq-WGAN model can achieve accurate prediction of continuous time series of free calcium and offer direction for subsequent production planning. This method has high practicality and application prospects, and can provide strong support for the production scheduling of the cement industry.
Fast-sampling fast-ion D-alpha measurement using multi-anode photomultiplier tube in large helical device
Authors: Kawachi Y. , Ogawa K. , Osakabe M. , Kawamoto Y. , Isobe M. , Ida K.
Published: October 2023

A fast-sampling fast-ion D-alpha (F-FIDA) measurement has been developed in the large helical device in order to investigate fast ion dynamics associated with helically trapped fast-ion-driven Magnetohydrodynamic (MHD) bursts. F-FIDA consists of a multi-anode photomultiplier tube (PMT) and achieves a sampling rate of 10 kHz. During the deuterium experiment campaign in 2022, F-FIDA measured the spectrum of perpendicular fast ions, using perpendicular lines of sight. We compared F-FIDA with conventional FIDA, using an electron multiplying charge coupled device, and confirmed that the time-averaged images were generally consistent between the two. The statistical properties of the temporal evolution associated with MHD bursts were analyzed using a conditional sampling technique. The results showed that the PMT signal varied in different spatial and wavelength channels. Although the signal-to-noise ratio was poor and there was room for improvement, it could provide useful information for studies on the phase-space dynamics of fast ions.
The influence of interface contact condition on resistive switching of Au/Nb:SrTiO3 heterojunctions
Authors: Li Jialu , Guo Wei , Qiao Yadong , Yao Li , He Zhiquan , Wang Fadi , Wang Yuhang , Wang Fengping
Published: October 2023

The influence of the interface contact condition on the resistive switching (RS) effects of metal/Nb:SrTiO3 heterojunctions was investigated. Two Au/Nb:SrTiO3 samples with or without in situ substrate cleaning treatment were fabricated. Through comparative analysis of I–V hysteresis and switching performance, it was observed that the RS effect in the heterojunction formed by the in situ cleaned Nb:SrTiO3 substrate was significantly weakened. In addition, the SEM image demonstrates intimate contact between metal and the in situ cleaned substrate. In contrast, the untreated Au/Nb:SrTiO3 interface exhibits poor contact. The poor contact, as confirmed by interface AFM and CAFM images, is responsible for the resistive switching observed. Our research provides an innovative approach to elucidating the mechanism of the resistive switching effect, which will pave the way for better application of the device.
Software-defined meta-optics
Authors: Audhkhasi Romil , Fröch Johannes E. , Zhan Alan , Colburn Shane , Majumdar Arka
Published: October 2023

Rapid advancements in autonomous systems and the Internet of Things have necessitated the development of compact and low-power image sensors to bridge the gap between the digital and physical world. To that end, sub-wavelength diffractive optics, commonly known as meta-optics, have garnered significant interest from the optics and photonics community due to their ability to achieve multiple functionalities within a small form factor. Despite years of research, however, the performance of meta-optics has often remained inferior compared to that of traditional refractive optics. In parallel, computational imaging techniques have emerged as a promising path to miniaturize optical systems, albeit often at the expense of higher power and latency. The lack of desired performance from either meta-optical or computational solutions has motivated researchers to look into a jointly optimized meta-optical–digital solution. While the meta-optical front end can preprocess the scene to reduce the computational load on the digital back end, the computational back end can in turn relax requirements on the meta-optics. In this Perspective, we provide an overview of this up-and-coming field, termed here as “software-defined meta-optics.” We highlight recent contributions that have advanced the current state of the art and point out directions toward which future research efforts should be directed to leverage the full potential of subwavelength photonic platforms in imaging and sensing applications. Synergistic technology transfer and commercialization of meta-optic technologies will pave the way for highly efficient, compact, and low-power imaging systems of the future.
Regulation of nanosecond pulse breakdown process by vertical magnetic field
Authors: Li Yutai , Fu Yangyang , Zhang Zhijin , Liu Zhigang , Hu Qin , Zou Xiaobing , Wang Xinxin , Jiang Xingliang
Published: October 2023

Effects of vertical magnetic field on the breakdown process of the nanosecond pulse discharge in atmospheric air are studied via two-dimensional particle-in-cell/Monte Carlo collision simulations. The numerical model is chosen and defined reasonably, with reference to experimental situations and literature reports. It is shown that when the applied magnetic field is strong enough, the evolutionary characteristics of the ionization channel are greatly affected due to the Lorentz force on charged particles. The impact is manifested macroscopically by the slowing down of the ionization channel evolution speed, the ionization channel shift, and the improvement of the discharge uniformity. At the microscopic level, the impact is mainly reflected in the regulation of the highest-energy electrons and the regulation of the overall electron energy distribution. That is, the adoption of a strong vertical magnetic field is capable of suppressing the generation of energetic electrons. The authors' results explicitly demonstrate the regulation of vertical magnetic field on the breakdown process of the nanosecond pulse discharge, which provides more comprehensive knowledge for the atmospheric air gap nanosecond pulse discharge physics and the theoretical basis for application design.
Signature of functional enzyme dynamics in quasielastic neutron scattering spectra: The case of phosphoglycerate kinase
Authors: Hassani Abir N. , Haris Luman , Appel Markus , Seydel Tilo , Stadler Andreas M. , Kneller Gerald R.
Published: October 2023

We present an analysis of high-resolution quasi-elastic neutron scattering spectra of phosphoglycerate kinase which elucidates the influence of the enzymatic activity on the dynamics of the protein. We show that in the active state the inter-domain motions are amplified and the intra-domain asymptotic power-law relaxation ∝t−α is accelerated, with a reduced coefficient α. Employing an energy landscape picture of protein dynamics, this observation can be translated into a widening of the distribution of energy barriers separating conformational substates of the protein.
Droplet impact on a microhole through a partially wetting surface
Authors: Alam Md. Nur E. , Tan Hua
Published: October 2023

In this study, we thoroughly investigate the impact dynamics of water droplets on a partially wetting substrate with a single hole. By conducting experiments using de-ionized water droplets and high-speed imaging, we observe various outcomes, including downward jetting without pinch-off, jetting with single and multiple pinch-offs, and the intriguing emergence of an upward jet during droplet recoil. A regime map is constructed to establish the relationship between the dynamics of the jet and the Weber number. We find the small amount of liquid leakage through the hole has a negligible effect on the maximum spreading of the droplet. We analyze the behavior of the downward jet resulting from droplet impact in terms of its length, speed, and breakup characteristics. The scaling relation between the maximum jet length before its breakup and the Weber number is derived and compared with experimental data. We find that the growth of the downward jet length follows a consistent power-law relationship with time regardless of impact velocity, while the maximum jet velocity scales linearly with the impact velocity, confirming the hydrodynamic focusing theory. The size of the head satellite droplet formed during the jet pinch-off process remains nearly constant across different Weber numbers. Additionally, we investigate the volume of ejected liquid through the microhole, observing an initial increase with the Weber number followed by a saturation point. The occurrence of the upward jet during droplet recoil is a significant finding, and we analyze its diameter, height, and velocity in relation to the Weber number.
Characterization of superconducting through-silicon vias as capacitive elements in quantum circuits
Authors: Hazard T. M. , Woods W. , Rosenberg D. , Das R. , Hirjibehedin C. F. , Kim D. K. , Knecht J. M. , Mallek J. , Melville A. , Niedzielski B. M. , Serniak K. , Sliwa K. M. , Yost D. R. W. , Yoder J. L. , Oliver W. D. , Schwartz M. E.
Published: October 2023

The large physical size of superconducting qubits and their associated on-chip control structures presents a practical challenge toward building a large-scale quantum computer. In particular, transmons require a high-quality-factor shunting capacitance that is typically achieved by using a large coplanar capacitor. Other components, such as superconducting microwave resonators used for qubit state readout, are typically constructed from coplanar waveguides, which are millimeters in length. Here, we use compact superconducting through-silicon vias to realize lumped-element capacitors in both qubits and readout resonators to significantly reduce the on-chip footprint of both of these circuit elements. We measure two types of devices to show that through-silicon vias are of sufficient quality to be used as capacitive circuit elements and provide a significant reduction in size over existing approaches.
On the relationship between solid particle attractors and thermal inhomogeneities in vibrationally driven fluid-particle systems
Authors: Santhosh Balagopal Manayil , Lappa Marcello
Published: October 2023

The present analysis extends earlier authors' work [Crewdson et al., “Two-dimensional vibrationally-driven solid particle structures in non-uniformly heated fluid containers,” Chaos 32, 103119 (2022); M. Lappa, “Characterization of two-way coupled thermovibrationally driven particle attractee,” Phys. Fluids 34(5), 053109 (2022); M. Lappa and T. Burel, “Symmetry breaking phenomena in thermovibrationally driven particle accumulation structures,” ibid.32(5), 053314 (2020); and M. Lappa, “The patterning behavior and accumulation of spherical particles in a vibrated non-isothermal liquid,” ibid.26(9), 093301 (2014)] on the existence of solid particle attractee in thermovibrational flow in order to identify new physical principles and enable increased control over the ability of particles to target desired locations into the host fluid. The causality between the thermal boundary conditions and the multiplicity and morphology of emerging particle structures is discussed, and new fundamental topological concepts are harnessed through the combination of two-dimensional and three-dimensional simulations. It is shown that the threefold relationship among the inclination of vibrations, the multi-directional nature of the imposed temperature gradient, and the dimensionality of the system itself can open up new pathways for additional classes of attractors. These can manifest themselves as compact particle structures or completely disjoint sets, apparently behaving as they were driven by different clustering mechanisms (coexisting in the physical space, but differing in terms of characteristic size, shape, and position). A variety of new solutions are presented for a geometry as simple as a cubic enclosure in the presence of localized spots of temperature on otherwise uniformly heated or cooled walls. In order to filter out possible asymmetries due to fluid-dynamic instabilities induced by the back influence of the solid mass on the fluid flow, the analysis is conducted under the constraint of one-way coupled phases.
Effects of roll motion on linear and nonlinear gap resonances in a moonpool excited by various incident-wave heights
Authors: Jing Penglin , He Guanghua , Chen Bangqi , Zhang Cheng , Ng Bingfeng
Published: October 2023

The linear and nonlinear gap resonances in a free-rolling moonpool are investigated using a two-dimensional in-house code based on the constrained interpolation profile method. This study primarily focuses on the effects of roll motion on hydrodynamic characteristics, taking into account both the linear gap resonance and the nonlinear process-driven gap resonances. The analysis of the incident-wave height is conducted to illustrate the relationship between higher-order harmonics and nonlinear gap resonances. Numerical results demonstrate that the resonant frequency is insensitive to the roll motion. However, the roll response plays an important role in influencing the vertical wave loads on the barges and affecting the energy conversion pattern in the fluid field. According to the analysis of the incident-wave height parameter, the magnitudes of resonance at the linear and nonlinear resonant points are approximately in sub-linear and superlinear relationships with the incident-wave height, respectively. Moreover, the vortex shedding modes around the entrance of the free-rolling moonpool gradually transit from being dominated by the pairs of vortices to being dominated by the single vortex as the gap resonance changes from linear to quartic.
White light emitting devices with high color rendering index and electrically adjustable color temperature
Authors: Zhao Hao , Zhao Yijun , Sheng Yuhang , Zhu Dan , Xing Fangjian , Liu Cihui , Di Yunsong , Zhang Yi , Zhou Weiping , Luo Guangsheng , Zhang Xiaowei , Gan Zhixing
Published: October 2023

Herein, we report a rare earth-free white light emitting composite for applications in solid-state lighting, which is made up of carbon nitride (CN) and Mn2+-doped perovskite quantum dots (PQDs). The correlated color temperature (CCT) is adjustable from 18 088 to 2926 K by varying the ratio of the two components. When the PQDs content is 2.88%, the white light emitting diode (W-LED) based on the CN/PQDs composite shows a competitive color rendering index of 88, a CCT of 5737 K, and a chromaticity coordinate of (0.327, 0.33), which is close to the standard white light. The light conversion efficiency of the composite is around 10%, which is attributed to the high photoluminescence efficiencies of the two components and weak photon reabsorption between them. Moreover, the CCT can be tuned from 4750 to 7315 K by changing the repetition frequency of the electrical input.
Run-and-tumble oscillator: Moment analysis of stationary distributions
Authors: Frydel Derek
Published: October 2023

When it comes to active particles, even an ideal gas model in a harmonic potential poses a mathematical challenge. An exception is a run-and-tumble particles (RTP) model in one dimension for which a stationary distribution is known exactly. The case of two dimensions is more complex, but the solution is possible. Incidentally, in both dimensions the stationary distributions correspond to a beta function. In three dimensions, a stationary distribution is not known but simulations indicate that it does not have a beta function form. The current work focuses on the three-dimensional RTP model in a harmonic trap. The main result of this study is the derivation of the recurrence relation for generating moments of a stationary distribution. These moments are then used to recover a stationary distribution using the Fourier–Lagrange expansion.
Simplicial graviton from selfdual Ashtekar variables
Authors: Wieland Wolfgang
Published: October 2023

In perturbative gravity, it is straight-forward to characterize the two local degrees of freedom of the gravitational field in terms of a mode expansion of the linearized perturbation. In the non-perturbative regime, we are in a more difficult position. It is not at all obvious how to construct Dirac observables that can separate the gauge orbits. Standard procedures rely on asymptotic boundary conditions or formal Taylor expansions of relational observables. In this paper, we lay out a new non-perturbative lattice approach to tackle the problem in terms of Ashtekar’s self-dual formulation. Starting from a simplicial decomposition of space, we introduce a local kinematical phase space at the lattice sites. At each lattice site, we introduce a set of constraints that replace the generators of the hypersurface deformation algebra in the continuum. We show that the discretized constraints close under the Poisson bracket. The resulting reduced phase space describes two complex physical degrees of freedom representing the two radiative modes at the discretized level. The paper concludes with a discussion of the key open problems ahead and the implications for quantum gravity.
An ultra-thin multifunctional chiral metasurface with asymmetric transmission, cross-polarization conversion, and circular dichroism for Ku- and K-band applications
Authors: Ahmed Afzal , Cao Qunsheng , Khan Muhammad Ismail , Sajjad Muhammad , Ahmed Fahad
Published: October 2023

In this paper, a bi-layered ultra-thin multifunctional chiral metasurface is proposed to obtain asymmetric transmission (AT), cross-polarization conversion (CPC), and circular dichroism (CD). The multifunctional chiral metasurface realizes an AT with more than 70% efficiency over a Ku-band frequency range from 14.3 to 15.8 GHz, while in the operating frequency band from 13.5 to 16.2 GHz, the CPC ratio is above 90%. In addition, the metasurface exhibits CD in the K-band with a CD parameter of 0.6 at 24 GHz. Furthermore, the functionalities of AT and CPC are stable with changes in the incident angle of up to 60° for both transverse-electric and transverse-magnetic electromagnetic waves. For verification of the anticipated concept, the proposed chiral metasurface is fabricated and measured. The proposed design can be used for potential applications in the Ku- and K-bands for satellite communication and radar.
ASTOR: the imaging beamline of the Argentine Neutron Beam Laboratory
Authors: Vega N A , Bertalot F M , Bazzana S , Peirone M , Santisteban J
Published: October 2023

The ASTOR instrument is a state-of-the-art neutron imaging instrument being developed by LAHN (Laboratorio Argentino de Haces de Neutrones or Argentinian Laboratory of Neutron Beams) to be installed on one of the cold neutron beams of the 30MW open pool reactor RA-10, currently under construction at the outskirts of Buenos Aires. ASTOR will have direct view to a D2 cold source and will include a primary collimator at 2.5m from its surface. Its design includes a beam conformation room with a set of exchangeable secondary collimators to further collimate the beam, and several devices (solid state filters, a velocity selector and a double crystal monochromator) to tailor the energy spectrum for specific applications. Downstream the beam, it will have an experimental room with ample space for objects and samples, and L/D ratios in the range 120-1500 with calculated fluxes of 3.7x108 n/cm2s and 2.4x106 n/cm2s respectively (E<25meV) and a maximum field of view of 25x25 cm2. It will also count with two rectangular pinholes to obtain increased resolution in one dimension without substantially decreasing the flux.
New Measurements on Borated Neutron Imaging Screens at Budapest Neutron Centre (BNC)
Authors: Schillinger B , Chuirazzi W , Cool S , Craft A , Kis Z , Szentmiklósi L , Tengattini A
Published: October 2023

The most commonly used screens for neutron imaging consist of 6LiF+ZnS. This type of screen yields the highest light output per detected neutron. For high resolution, gadolinium-oxisulfide (Gadox) screens are employed, which have a much higher detection efficiency, but a light output much lower than LiF+ZnS that measurements are often limited by photon statistics. Screens using boron as neutron sensitive material have not been very successful in the past but recently, a new preparation method was introduced that combines light output 5-6 times higher than Gadox with detection efficiency larger than LiF+ZnS. Previous measurements were performed at FRM II, Garching, and ILL, Grenoble, which already matched a Gadox screen in resolution, but still contained too many inhomogeneities in the detector material’s grains to produce an optimized detector. We report about the most recent measurements of new borated screens produced with an improved milling process at the NORMA facility at Budapest Neutron Centre (BNC), in comparison to a high resolution Gadox screen.
Neutron autoradiography with nuclear tracks detectors: an imaging technique for Boron Neutron Capture Therapy
Authors: Portu Agustina M , Espain Maria S , Viglietti Julia S , Martin Gisela Saint
Published: October 2023

Boron Neutron Capture Therapy (BNCT) is a radiation treatment modality for cancer based on the 10B(n,α)7Li (BNC) reaction. Knowledge of the spatial location of boron atoms is essential when considering a BNCT treatment, since the BNC reaction products cause lethal damage in a range comparable to cell diameter. Neutron autoradiography is a technique able to provide this information with high resolution at relatively low cost. First a boron-loaded biological matrix is laid on a nuclear track detector (NTD). By irradiating this assembly with thermal neutrons, the emitted particles of the BNC reaction produce damaged zones in the NTD along each incident ion trajectory, and by mapping these nuclear tracks boron spatial distribution in the sample can be assessed. In our laboratory, we have established different approaches: high fluence autoradiography (HFA), to observe boron microdistribution through differences in shades of gray; quantitative autoradiography (QTA), which allows the correlation between track density measurements and boron concentration; and UV-C sensitization of polymers (UVC-a), which produces an imprint of the biological material in the NTD, thus improving the spatial resolution. Moreover, we aim to develop a technique using commercial CMOS sensors in order to simultaneously detect the BNC events and the image of the biological sample during irradiation. The objective of this work is to describe the mentioned approaches and to discuss future perspectives.