bluuebunny/crossref_metadata_2025 huggingface dataset:
Mass production of a dealloyed Pt3Co/C catalyst for oxygen reduction catalysis in PEMFCs
Authors: Liu Yanhui , Zhan Changhong , Zhang Juntao , Huang Xiaoqing , Bu Lingzheng
Published: December 2022

D-Pt3Co/C with remarkable ORR/MEA performances has been prepared on a large scale. This robust method can be readily extended to prepare many ternary, quaternary and quinary Pt3Co-based alloy catalysts, demonstrating great potential in PEMFCs.
A single-ion gel polymer electrolyte based on polyimide grafted with lithium 3-chloropropanesulfonyl (trifluoromethanesulfonyl) imide for high performance lithium ion batteries
Authors: Li Zhangnan , Liu Yuhan , Liang Xiaoxiao , Yu Mengxuan , Liu Baijun , Sun Zhaoyan , Hu Wei , Zhu Guangshan
Published: December 2022

A polyimide-based single-ion polymer PI-LiCPSI was prepared. PI-SIGPE obtained by compounding of PI-LiCPSI and PVDF-HFP showed good mechanical properties due to the rigid frame and strong interface, and also possessed excellent electrochemical and cycling performance.
A chemically bonded and plasmonic Z-scheme junction for high-performance artificial photosynthesis of hydrogen peroxide
Authors: Shao Teng , Chang Yuan , Li Zhuwei , Song Yurou , Jin Dingfeng , Gao Junfeng , Sun Licheng , Hou Jungang
Published: December 2022

Chemically bonded and plasmonic Z-scheme junction as a model material was produced byin situassembly of nonstoichiometric W18O49(WO) onto two-dimensional carbon nitride nanosheets (CNs) for high-performance artificial photosynthesis of H2O2.
Development of pH sensing colloidal nanoparticles and oil/water separating electrospun membranes containing oxazolidine from functional polymers
Authors: Babazadeh-Mamaqani Milad , Roghani-Mamaqani Hossein , Alidaei-Sharif Hossein , Salami-Kalajahi Mehdi
Published: December 2022

Functionalized polymers with carboxylic acid groups were synthesized and used to prepare nanoparticles and nanofibers containing oxazolidine by nanoprecipitation and electrospinning, which were used as pH sensor and oil/water separator, respectively.
A promising ultraviolet nonlinear optical crystal: Rb3Ba3Li2Al4B6O20F—crystal growth, physical properties, and 266 nm laser generation
Authors: Wang Jiankang , Wu Hongping , Hu Zhanggui , Wang Jiyang , Wu Yicheng , Yu Hongwei
Published: December 2022

The Rb3Ba3Li2Al4B6O20F crystal is a competitive ultraviolet NLO crystal, which not only can output 266 nm laser but also exhibits excellent comprehensive performances, such as large NLO coefficient, small walk-off and large acceptance angles.
The reuse of electronic components from waste printed circuit boards: a critical review
Authors: Zhao Wenting , Xu Junqing , Fei Wenlei , Liu Ziang , He Wenzhi , Li Guangming
Published: December 2022

As a key component of all electrical and electronic equipment, waste printed circuit boards (WPCBs) are an important target for waste electrical and electronic equipment (WEEE) treatment.
A bottom‐up design methodology of neural min‐sum decoders for LDPC codes
Authors: Li Guangwen , Yu Xiao , Luo Yuan , Wei Guangfen
Published: December 2022

It is known the belief propagation variants of linear codes can be readily unrolled as neural networks, after assigning learnable weights on the message‐passing edges. Contrary to the conventional top‐down training process, where the distillation occurs in the form of pruning or sharing when downsizing model is required, a new bottom‐up design methodology to augment performance of the raw min‐sum decoder of LDPC codes is proposed, by introducing incrementally a few parameters in the specific positions of corresponding neural network. Then a novel postprocessing method, devised to further improve performance, can cope with decoding failures effectively. In the training process, a simplified scheme of generating training data is presented via exploiting an approximation to the targeted mixture density, and it is found the evaluation of trained parameters converges after sufficient iterations, indicating its generality with an arbitrary designated number of iterations. Lastly, an extensive simulation of three codes carried on the AWGN or Rayleigh fading channels demonstrates the design reaches a good tradeoff of low‐complexity and comparable decoding performance.
Design procedure and optimisation methodology of permanent magnet synchronous machines with direct slot cooling for aviation electrification
Authors: Tameemi Ahmed , Degano Michele , Murataliyev Mukhammed , Di Nardo Mauro , Valente Giorgio , Gerada David , Xu Zeyuan , Gerada Chris
Published: December 2022

Electric machines are widely employed in a variety of sectors, including automotive and aerospace industry. With the rising trend towards electrification in aviation, electric machines with increased power density and efficiency are becoming key enabling technologies, requiring the development of innovative design procedures. In this study, a preliminary design procedure for Surface Mounted Permanent Magnet Synchronous Machines (SPMSMs) intensively cooled by means of oil channels placed in the stator slots is proposed. The analytical derivation of SPMSM sizing equations, including the sub‐domain model and optimisation algorithm will be reported in detail. Indeed, both the electromagnetic and thermal equations of the machine are considered for the derivation of the sizing tool. As a result, the latter allows to capture variation of the machine design not only in terms of mechanical demands, such as power and speed, but also in terms of coolant characteristics, and can be effectively employed to perform trade‐off studies at a preliminary design stage. The proposed design tool will be used for a specific case study: The design of a high‐speed machine for an aerospace hydraulic actuator. The accuracy of the proposed design tool is validated for different parameters by comparing the results to experimental measurements performed on an existing 8‐pole 9‐slot prototype SPMSM.
Increase of nuclear installations safety by better understanding of materials performance and new testing techniques development (MEACTOS, INCEFA-SCALE, and FRACTESUS H2020 projects)
Authors: Brynk Tomasz , Perosanz Lopez Francisco Javier , McLennan Alec
Published: December 2022

Research to better understand the phenomena influencing materials and components’ performance is important for increasing the safety of Generation II and III nuclear plants. A crucial step for improving nuclear safety is the development of new experimental techniques that can provide the necessary data. The three H2020 projects presented in this paper, MEACTOS (2017–2022), INCEFA-SCALE (2020–2025), and FRACTESUS (2020–2024), cover the steps needed to realize those safety improvements. The goal of the MEACTOS project is to improve the resistance of critical locations, including welds, to environmentally-assisted cracking through optimizing surface machining and treatments. The project is currently in its final stage, and the complete analysis of the data is finished. The objective of INCEFA-SCALE is to improve predictions of component fatigue lifetime when subjected to Environmentally-Assisted Fatigue (EAF). The strategy consists of producing guidance on how to appropriately accommodate variable amplitude and plant-relevant loading in EAF assessments. Increasing the understanding of the EAF mechanism based on substantial testing, characterization, and analysis program will support the INCEFA-SCALE strategy. The FRACTESUS project will validate the use of miniaturized compact tension specimens by comparing the results of master curve-oriented fracture toughness tests performed with small and large specimens. The round-robin exercises will use irradiated and non-irradiated Reactor Pressure Vessel (RPV) materials. The material selection process is complete in time for the project to enter the testing phase. The output of the project will be beneficial from a long-term operation perspective and a saving in the material amount needed for RPV surveillance programs. Even though each project is devoted to different research areas, common aspects are clearly visible. All three projects investigate phenomena that are relevant to the performance and safe operation of the nuclear plant. Moreover, each project will provide valuable databases and analyses of test results for materials relevant to components in the nuclear plant. The output of these projects will be of great value to the nuclear industry. This paper presents the current progress for each project, emphasizing the common research domains between the projects.
Development of Internet of Things (IoT) Based Monitoring of Hazardous Exhaust Compounds in Air - A Review
Authors: Bagal Shishir A. , Choudhari Nitin K. , Chaudhari A. R.
Published: December 2022

Presence of pollutants in Air is the most prominent problem globally confronted now a day. The extreme use of fueled vehicles and rapid urbanization has deteriorated the air quality. This deteriorated air contains hazardous compounds like Mono-oxides & Di-oxides of carbon, Sulphur, Nitrogen, Atmospheric Particulate Matter. Exposure to such hazardous compounds in the air for a long time can cause damage to the human health. Traditional air monitoring systems consists of monitoring stations. As far as traditional air quality monitoring methods are concerned, they are highly expensive and requires a regular maintenance. Due to these limitations, these stations are deployed in small numbers and also it provides indicative values of the sensed data. This monitored data has low resolution and precision. This paper proposes framework for the development of smart and portable system using Internet of Things (IoT) for monitoring of hazardous exhaust compounds in the air using real time. This framework consists of different types of sensors and a controller that are used for monitoring and assessment of the air quality. Also it is used to check the presence of hazardous compounds emitted by different industries and share this data through IOT. The outcome of the proposed research work can be utilized by industries as well as by other agencies to carry out an audit of hazardous exhaust components present in air, so as to take necessary precautions and to save human.
Traffic Signboard Recognition and Text Translation System using Word Spotting and Machine Learning
Authors: Usha S. M. , Kumar D. Mahesh , Mahesh H. B.
Published: December 2022

This project will help the non-native people of Karnataka to easily understand the kannada boards and travel easily. The main task of this work is to recognize the kannada traffic text boards and translate that to English language. Histogram equalization is used to find the gap between the characters. K-means clustering is used to divide the characters into different clusters then the segmented characters are passed to the pretrained model to recognize what the characters means. The model used for recognizing the traffic text is convolutional neural networks. The methodologies used here is the image augmentation, converting RGB image to grey scale and normalizing the image to reduce the noise. The validation accuracy obtained while training the model with coloured images, normalized image, grey scale image and normalized grey scale image is respectively 98.88%, 98.85%, 98.8% and 99.39% and while testing this model with kannada language, the testing accuracy obtained respectively with coloured images, normalized image, grey scale and normalized grey scale image is 95.91%, 96.58%, 95.42% and 96.98 % . In this work, word spotting method is employed for kannada language recognition. The performance of this system is faster since machine learning algorithms are used here.
Chat Application Using Homomorphic Encryption
Authors: Behera Sagarik , Kanth Ashwin , Adithya Suresh Avik , Ashwin CVR , Rani Prathuri Jhansi
Published: December 2022

Chat applications nowadays have evolved into one of the most significant and widely used applications on smart devices. They are capable of sending and receiving messages, documents, and images with zero cost to any part of the world. All the messages should be protected. All the chat applications today are used to send messages quickly and securely. The actuality of the situation is that the messages sent are not as secure as they claim to be. So, to bridge this gap, in this paper Homomorphic Encryption is used to secure the messages further while also not reducing the speed of the transaction. This paper aims to implement a Chat application using Homomorphic Encryption which adds a layer of security over end-to-end encryption.
Nosokomiale Infektionsgefährdung und Prävention in
der neurologisch-neurochirurgischen Frührehabilitation
Authors: Kramer Axel , Platz Thomas
Published: December 2022

Deutschlands Rehabilitationseinrichtungen bilden die zweite große
Säule der stationären Patientenversorgung. Die für den
Rehabilitationserfolg entscheidenden multimodalen Therapien weisen regelhaft
einen engen Kontakt der Behandelnden zu Patient*innen auf, was mit
vielfältigen Übertragungsmöglichkeiten für
Infektionen verbunden ist. Aus diesem Grund sollte zur
Infektionsprävention in der neurologisch-neurochirurgischen
Frührehabilitation (NNFR) – insbesondere wegen der im Vergleich
zu anderen Rehabilitationsformen höheren Infektionsrisiken – ein
der Patientenklientel angepasstes Präventionskonzept aufgestellt
werden.
Funktion und Rolle der KRINKO
Authors: Mehrholz Jan , Pohl Marcus
Published: December 2022

Wie arbeitet die Kommission für Krankenhaushygiene und
Infektionsprävention (KRINKO)? Wie setzt sie sich zusammen bzw. wer
arbeitet dort mit? Welche Empfehlungen werden überhaupt herausgegeben?
Und welcher Bezug besteht hier zur tagtäglichen Arbeit in der
neurologischen Rehabilitation? Prof. Marcus Pohl gibt als Mitglied der aktuellen
KRINKO Antworten.
Factors Influencing Performance in Laparoscopic Suturing and Knot Tying: A Cohort Study
Authors: Armbrust Lina , Lenz Moritz , Elrod Julia , Kiwit Antonia , Reinshagen Konrad , Boettcher Johannes , Boettcher Michael
Published: December 2022

Background Laparoscopic suturing and knot tying are regarded as some of the most difficult laparoscopic skills to learn. Training is essential to reach proficiency, but available training opportunities are limited. Various techniques to improve training have been evaluated. It appears that individual-related factors affect initial performance and response to training. Thus, the current study aimed to assess factors influencing laparoscopic-suturing and knot-tying performances.

Methods All patients were trained one-on-one (teacher–student) for 3 hours. Patients were tested before training (bowel anastomosis model) and directly after training (congenital diaphragmatic hernia or esophageal atresia model) to evaluate transferability. Primary endpoints were time, knot quality, precision, knot strength, and overall laparoscopic knotting performance. Moreover, factors such as (1) age, (2) gender, (3) handedness, (4) previous training or operative experience, (5) playing an instrument, (6) sportive activities, and (7) computer gaming which may influence the primary endpoints were assessed.

Results In total, 172 medical students or novice surgical residents were included. Training significantly improved all outcome parameters assessed in the current study. More than 50% of the patients reached proficiency after 3 hours of training. Personal factors like operative experience, playing music instruments, sportive activities, and computer gaming affected some outcome parameters. Handedness and gender affected initial performance but differences partially subsided after training. Younger participants showed a much better response to training.

Conclusion In conclusion, several factors influence initial performance and response to the training of laparoscopic suturing and knot tying. Surgeons who want to improve their laparoscopic performance, should concentrate on playing a musical instrument and performing sports rather than playing videos gaming. It appears that training is a key and more practice opportunities should be incorporated into medical school and surgical curricula. Moreover, handedness may affect the outcome but only if the training concepts are not tailored to the dominant hand of the surgeon. Future training and surgical curricula should adapt to this and tailor their concepts accordingly.
Outcomes after Surgical Treatment for Rectal Atresia in Children: Is There a Preferred Approach? A Systematic Review
Authors: de Beaufort Cunera M. C. , Derikx Joep P. M. , de Jong Justin R. , Burchell George L. , Bosscha Sterre R. J. , de Beer Sjoerd A. , van Heurn Lodewijk W. Ernest , Gorter Ramon R.
Published: December 2022

Rectal atresia (RA) affects only 1 to 2% of all children with anorectal malformations. No consensus on optimal treatment strategy is yet achieved. Therefore, the aim of this systematic review is to summarize all surgical interventions for RA and outcomes described in the current literature. A literature search was conducted in PubMed, Embase, Web of Science, and Cochrane Library on January 24, 2022. All studies describing treatment for RA in children (< 18 years) were included. Operation technique and postoperative complications were listed. Only descriptive analysis was anticipated. Quality of the studies was assessed using Johanna Briggs Institute critical appraisal checklist for case reports and series. The search yielded 6,716 studies of which, after duplicate removal, 4,028 were excluded based on title and abstract screening. After full-text assessment, 22 of 90 studies were included, yielding 70 patients. Posterior sagittal anorectoplasty (PSARP) and pull-through were most performed (43/70 and 18/70 patients, respectively). Four patients experienced postoperative complications: anal stenosis (n = 1), anastomotic stenosis (n = 2), and death due to a pulmonary complication (n = 1). In the low-quality literature available, most patients with RA are treated with PSARP or pull-through technique. A low complication rate of both has been described but follow-up was often not mentioned. Larger well-designed studies should be performed to determine optimal treatment strategy for children with RA. This study reflects level of evidence V.
Integrating a Patient Engagement App into an Electronic Health Record-Enabled Workflow Using Interoperability Standards
Authors: Lobach David F. , Boxwala Aziz , Kashyap Nitu , Heaney-Huls Krysta , Chiao Andrew B. , Rafter Thomas , Lomotan Edwin A. , Harrison Michael I. , Dymek Chris , Swiger James , Dullabh Prashila
Published: December 2022

Background Patient use of mobile health applications is increasing. To promote patient-centered care, data from these apps must be integrated into clinician workflows within the electronic health record (EHR). Health Level 7 Fast Healthcare Interoperability Resources (FHIR) offers a standards-based application programming interface (API) that may support such integration.

Objective We aimed to use interoperability standards to integrate a patient mobile application (coronavirus 2019 [COVID-19] Tracker) with an EHR. The COVID-19 Tracker engages patients by sending introductory and reminder text messages, collecting vital signs and symptom data from COVID-19 patients, and providing actionable guidance if concerning issues are identified. This case report explored the use of FHIR APIs to integrate the app into EHR-enabled clinical workflows.

Methods The authors used notes from project meetings and from semistructured discussions among the application development team to track the design and implementation processes. Seven points of integration between the application and the EHR were identified, and approaches using FHIR to perform these integrations were delineated.

Results Although this clinical decision support integration project benefited from its standards-based approach, many challenges were encountered. These were due to (1) partial implementation of the FHIR standard in the EHR, particularly, components needed for patient engagement applications; (2) limited experience with the adoption of FHIR standards; and (3) gaps in the current FHIR standard. Alternative approaches, often not based on interoperability standards, were developed to overcome these limitations.

Conclusion Despite the challenges encountered due to the early stages of FHIR development and adoption, FHIR standards provide a promising mechanism for overcoming longstanding barriers and facilitating the integration of patient engagement apps with EHRs. To accelerate the integration of apps into clinical workflows, additional components of the FHIR standard must be implemented within the EHR and other clinical systems. Continued expansion of available FHIR resources will help with tighter workflow integration.
Parameter range estimation and uncertainty analysis for high strain rate material response via model fusion
Authors: James J. R. , Gonzales M. , Gerlt A. R. C. , Payton E. J. , John R. , Arroyave R. , Allaire D. L.
Published: December 2022

The dynamic stress–strain response of a material can be described by a number of different models of varying fidelity. However, an individual model’s ability to replicate the dynamic stress–strain response of a material can be hindered by experimental variability. Reification, an approach to fusing models and experimental data with inherent scatter, is presented. It is then used to determine the optimum parameters of the Johnson–Cook (JC) and Zerilli–Armstrong (ZA) models using a fusion of Split-Hopkinson Pressure Bar (SHPB) data and the JC and ZA models fit to the SHPB data using a traditional approach. The output of the fused model is a dataset that represents a “best-guess” sampling of the possible stress–strain response of a high strength steel. In the present work, the dynamic response of a newly developed steel, AF9628, is evaluated. Under the reification framework, the experimental variability and limitations of the mathematical model expressions are addressed by the optimized sampling of data and combined fitting process. The JC and ZA models are then re-fit to partitions of the fused dataset, which bound the responses of the traditionally fit JC and ZA models. The behavior of the re-fit models and the traditionally fit models are compared via a simulated Taylor anvil test.
Ferromagnetism enhancement by increasing oxygen vacancies in Co-doped ZnO thin films
Authors: Udagawa Kota , Murayama Mariko , Zhao Xinwei
Published: December 2022

In the reported study, thin films of ZnO doped with 10 wt. % Co were fabricated by pulsed laser deposition under different oxygen partial pressures. The results of x-ray photoelectron spectroscopy show that the valence state of the Co ions is 2+ and that the number of oxygen vacancies is increased by lowering the oxygen partial pressure during deposition. The results of UV–visible absorption spectroscopy show that the Co2+ ions substitute for the Zn sites in the ZnO lattice. Ferromagnetism in the Co-doped ZnO thin films is observed up to 300 K. Furthermore, the saturation magnetization increases as the oxygen partial pressure decreases, indicating a strong correlation between the number of oxygen vacancies and the saturation magnetization. This suggests that ferromagnetism in Co-doped ZnO can be enhanced by simply controlling the oxygen partial pressure that causes oxygen vacancies. Furthermore, how the mechanism for the expression of ferromagnetism can be explained by the bound magnetic polaron model is discussed.
Sign reversal of the anomalous Hall effect in antiperovskite (110)-oriented Mn3.19Ga0.81N1−δ film
Authors: Han Huimin , Sun Ying , Shi Kewen , Yuan Xiuliang , Ren Jie , Cui Jin , Hu Dongmei , Zhang Kaiqi , Wang Cong
Published: December 2022

Antiperovskite compounds with abundant magnetic phase transitions provide an ideal platform for exploring nontrivial magnetotransport responses. In this study, the anomalous Hall effect (AHE) in an antiperovskite (110)-oriented Mn3.19Ga0.81N1−δ film up to room temperature was observed, and an unusual sign reversal was detected in the Hall measurements. The AHE reversal suggests that the carrier reversal corresponds to a magnetic transition from a ferrimagnetic order to noncollinear antiferromagnetic order at about 240 K. Analysis of the scaling relation of AHE indicates that the sign reversal originates from the transition from the skew scattering dominated AHE to the intrinsic mechanism dominated AHE. These findings will inspire effective control of the magnetic configuration and innovative applications for manipulating carrier transport in spintronic memory devices based on antiperovskite films.
Chemical order transitions within extended interfacial segregation zones in NbMoTaW
Authors: Aksoy Doruk , McCarthy Megan J. , Geiger Ian , Apelian Diran , Hahn Horst , Lavernia Enrique J. , Luo Jian , Xin Huolin , Rupert Timothy J.
Published: December 2022

Interfacial segregation and chemical short-range ordering influence the behavior of grain boundaries in complex concentrated alloys. In this study, we use atomistic modeling of a NbMoTaW refractory complex concentrated alloy to provide insight into the interplay between these two phenomena. Hybrid Monte Carlo and molecular dynamics simulations are performed on columnar grain models to identify equilibrium grain boundary structures. Our results reveal extended near-boundary segregation zones that are much larger than traditional segregation regions, which also exhibit chemical patterning that bridges the interfacial and grain interior regions. Furthermore, structural transitions pertaining to an A2-to-B2 transformation are observed within these extended segregation zones. Both grain size and temperature are found to significantly alter the widths of these regions. An analysis of chemical short-range order indicates that not all pairwise elemental interactions are affected by the presence of a grain boundary equally, as only a subset of elemental clustering types are more likely to reside near certain boundaries. The results emphasize the increased chemical complexity that is associated with near-boundary segregation zones and demonstrate the unique nature of interfacial segregation in complex concentrated alloys.
A numerical investigation of flow dynamics inside wall cavity and strut cavity placed in supersonic airflows
Authors: Dhankarghare A. A. , Jayachandran T. , Muruganandam T. M.
Published: December 2022

A study on flow dynamics in strut cavity and wall cavity in different freestream Mach numbers using numerical simulations has been conducted. A strut cavity is the space between two struts longitudinally aligned next to each other, and a wall cavity is the cavity in the wall. Our earlier results showed that both cavities exhibited oscillations for low values of supersonic Mach numbers, while oscillations decreased for high values. However, the strut cavity responded better to the change in Mach number than the wall cavity. The present work explores wave propagation and wave interactions inside the cavities in different Mach number flows. It is shown that the flow velocity inside a cavity affects wave propagation. Secondary recirculation inside the cavities has been discussed. The work also revisits the process of wave generation inside the cavities. Furthermore, an insight into the vortex propagation along the cavity length has also been provided. The results suggest that the vortex velocity may not remain uniform throughout the cavity length and may depend on the flow Mach number. Finally, the mass exchange between the cavity and the freestream is described and compared for different cavities. Flow particles are tracked in the shear layer and inside the cavity to suggest the locations of mass exchange.
Simultaneous determination of Young's modulus and Poisson's ratio in metals from a single surface using laser-generated Rayleigh and leaky surface acoustic waves
Authors: Canfield Ryan , Ziaja-Sujdak Aleksandra , Pitre John J. , O’Donnell Matthew , Ambrozinski Lukasz , Pelivanov Ivan
Published: December 2022

Material elastic moduli are used to assess stiffness, elastic response, strength, and residual life. Ultrasound (US) measurements of propagation wave speeds (for longitudinal and shear waves) are now primary tools for non-destructive evaluation (NDE) of elastic moduli. Most US techniques measure the time-of-flight of through-transmission signals or reflected signals from the back wall. In both cases, an independently determined sample thickness is required. However, US methods are difficult for complex (non-flat) samples. When the local thickness is unknown, the propagation speed cannot be determined. On the other hand, the propagation speed of Rayleigh waves can be calculated without knowledge of sample thickness, but another independent measurement is still required to compute both Young's modulus and Poisson's ratio. We present a comprehensive theoretical background, numerical simulations, and experimental results that clearly show that when the material density is assumed known, both elastic constants of an isotropic metal sample can be determined with laser-ultrasound by tracking two types of surface propagating waves without any sample contact (both signal excitation and detection are performed optically). In addition to a conventional surface, or Rayleigh, acoustic wave, a leaky surface wave can also be launched with nanosecond laser pulses in the thermoelastic regime of excitation (i.e., without material ablation) close to the source that propagates along the sample surface with speed close to that of bulk longitudinal waves. Samples can be of arbitrary shape and their thickness need not be measured.
The propulsion of tandem flapping foil following fishtailed flapping trajectory
Authors: Swain Prafulla Kumar , Barik Ashok K. , Dora Siva Prasad , Resapu Rajeswara
Published: December 2022

It has always been a challenge to implement the natural flyer and swimmer kinematics into human-made aero/hydro vehicles for the enhancement of their performance. The propulsive performance of underwater vehicles can be enhanced by following the fishtailed kinematics. In the present study, a two-dimensional simulation has been performed on a tandem flapping foil by altering the simple flapping trajectory motion to a fishtailed trajectory by varying the Strouhal number (St) in the range of 0.1–0.5. The effect of the inter-foil spacing and phasing between the foils on wake interaction is also investigated. The results show that fishtailed trajectory motion and inter-foil spacing of 2cm–3cm (where cm is the mean chord length) between the foils would enhance the propulsive efficiency of the downstream foil by up to 41%. The unfavorable spacing between the foils results in adverse wake interaction, which reduces the propulsive efficiency compared to solo flapping foil.
Application and effect analysis of renewable energy in a small standalone automatic observation system deployed in the polar regions
Authors: Wang Jin , Dou Yinke , Zuo Guangyu , Lan Musheng , Chang Xiaomin , Yang Bo , Du Zhiheng , Yu Miaoyuan , Mao Qingyang
Published: December 2022

Considering the difficulty of power supply for automatic observation equipment in the polar regions, this paper introduced a small standalone renewable energy system with wind–solar co-generation as the energy supply scheme. Mathematical models were given, including solar photovoltaic panels, wind turbines, solar irradiance, wind energy density, and renewable energy assessment. ERA-Interim atmospheric reanalysis data were used to evaluate solar energy resources, and the synergistic effect of wind–solar resources on renewable energy was also analyzed and discussed. The system composition of the small standalone renewable energy system was proposed in this study. This system deployed near Zhongshan Station was taken as the object of investigation to analyze the operation performance of each component of the system in different months, and the technical feasibility of the system has also been verified. The results showed that the wind–solar resources in the polar regions had a synergistic effect, which can provide an effective and feasible scheme for the power supply of automatic observation equipment. Through research and analysis, it was found that each component of the renewable energy system, including photovoltaic panels, wind turbines, and batteries, could meet the long-term power supply requirements of automatic observation regardless of the polar periods, polar day or polar night. This paper can not only provide theoretical and data support for the application of small independent renewable energy systems in the polar regions but also provide feasible solutions for clean energy supply of the systems and equipment for independent observation stations deployed in uninhabited islands and alpine regions.
Reduced effective magnetization and damping by slowly relaxing impurities in strained γ-Fe2O3 thin films
Authors: Müller Manuel , Scheufele Monika , Gückelhorn Janine , Flacke Luis , Weiler Mathias , Huebl Hans , Gepraegs Stephan , Gross Rudolf , Althammer Matthias
Published: December 2022

Magnetically ordered insulators are of key interest for spintronics applications, but most of them have not yet been explored in depth regarding their magnetic properties, in particular with respect to their dynamic response. We study the static and dynamic magnetic properties of epitaxially strained γ-Fe2O3 (maghemite) thin films grown via pulsed-laser deposition on MgO substrates by SQUID magnetometry and cryogenic broadband ferromagnetic resonance experiments. SQUID magnetometry measurements reveal hysteretic magnetization curves for magnetic fields applied both in- and out of the sample plane. From the magnetization dynamics of our thin films, we find a small negative effective magnetization in agreement with a strain induced perpendicular magnetic anisotropy. Moreover, we observe a non-linear evolution of the ferromagnetic resonance-linewidth as a function of the microwave frequency and explain this finding with the so-called slow relaxor model. We investigate the magnetization dynamics and non-linear damping mechanisms present in our samples as a function of frequency and temperature and in particular, observe a sign change in the effective magnetization from the transition of the magnetic anisotropy from a perpendicular easy axis to an easy in-plane anisotropy for reduced temperatures. Its nonlinear damping properties and strain-induced perpendicular anisotropy render γ-Fe2O3 an interesting material platform for spintronics devices.
The protein escape process at the ribosomal exit tunnel has conserved mechanisms across the domains of life
Authors: Bui Phuong Thuy , Hoang Trinh Xuan
Published: December 2022

The ribosomal exit tunnel is the primary structure affecting the release of nascent proteins at the ribosome. The ribosomal exit tunnels from different species have elements of conservation and differentiation in structural and physico-chemical properties. In this study, by simulating the elongation and escape processes of nascent proteins at the ribosomal exit tunnels of four different organisms, we show that the escape process has conserved mechanisms across the domains of life. Specifically, it is found that the escape process of proteins follows the diffusion mechanism given by a simple diffusion model, and the median escape time positively correlates with the number of hydrophobic residues and the net charge of a protein for all the exit tunnels considered. These properties hold for 12 distinct proteins considered in two slightly different and improved Gō-like models. It is also found that the differences in physico-chemical properties of the tunnels lead to quantitative differences in the protein escape times. In particular, the relatively strong hydrophobicity of E. coli’s tunnel and the unusually high number of negatively charged amino acids on the tunnel’s surface of H. marismortui lead to substantially slower escapes of proteins at these tunnels than at those of S. cerevisiae and H. sapiens.
Influence of chemistry and structure on interfacial segregation in NbMoTaW with high-throughput atomistic simulations
Authors: Geiger Ian , Luo Jian , Lavernia Enrique J. , Cao Penghui , Apelian Diran , Rupert Timothy J.
Published: December 2022

Refractory multi-principal element alloys exhibiting promising mechanical properties such as excellent strength retention at elevated temperatures have been attracting increasing attention. Although their inherent chemical complexity is considered a defining feature, a challenge arises in predicting local chemical ordering, particularly in grain boundary regions with an enhanced structural disorder. In this study, we use atomistic simulations of a large group of bicrystal models to sample a wide variety of interfacial sites (grain boundary) in NbMoTaW and explore emergent trends in interfacial segregation and the underlying structural and chemical driving factors. Sampling hundreds of bicrystals along the [001] symmetric tilt axis and analyzing more than one hundred and thirty thousand grain boundary sites with a variety of local atomic environments, we uncover segregation trends in NbMoTaW. While Nb is the dominant segregant, more notable are the segregation patterns that deviate from expected behavior and mark situations where local structural and chemical driving forces lead to interesting segregation events. For example, incomplete depletion of Ta in low-angle boundaries results from chemical pinning due to favorable local compositional environments associated with chemical short-range ordering. Finally, machine learning models capturing and comparing the structural and chemical features of interfacial sites are developed to weigh their relative importance and contributions to segregation tendency, revealing a significant increase in predictive capability when including local chemical information. Overall, this work, highlighting the complex interplay between the local grain boundary structure and chemical short-range ordering, suggests tunable segregation and chemical ordering by tailoring grain boundary structure in multi-principal element alloys.
Versatile focal field design using cascaded artificial neural network
Authors: Luan Guangrui , Lin Jian
Published: December 2022

Both forward and inverse design methods have been developed for focal field engineering, which has applications in many areas including super-resolution imaging and optical lithography, high-density optical storage, and particle manipulation. However, a certain method is normally targeted at a unique focal field distribution. Here, we report on a versatile focal field design method based on a cascaded artificial neural network (CANN) for the inverse design of focal field distributions in a high numerical aperture focusing system. The CANN consists of a forward and an inverse artificial neural network. Once trained properly, the CANN can predict modulation phase patterns for multiple focal field distributions. We demonstrate the effectiveness of the CANN by the design of focal field distributions along the optical axis including a uniform optical needle and an anti-point spread function with lengths up to 14 wavelengths and multiple focal spots with controllable intensities as well as those in the focal plane including flat-top and sub-diffraction focal spots.
Paint drop spreading on wood and its enhancement by an in-plane electric field
Authors: Granda Rafael , Yurkiv Vitaliy , Mashayek Farzad , Yarin Alexander L.
Published: December 2022

Experimental observations of drops of water with aniline dye softly located or impacting onto balsa wood substrates were used to elucidate the effect of an in-plane electric field (at a high voltage of 10 kV applied) on drop behavior. The top and side views were recorded simultaneously. The short-term recordings (on the scale of a few ms) demonstrated a slight effect of the applied in-plane electric field. In some trials, a greater number of finger-like structures were observed along the drop rim compared to the trials without voltage applied. These fingers developed during the advancing motion of the drop rim. The long-term recording (on the scale of ∼10 s) was used to evaluate the wettability-driven increase in the area-equivalent radius of the wetted area. These substrates had grooves in the inter-electrode or the cross-field directions. The groove directions affected the wettability-driven spreading and imbibition. The wettability-driven spreading in the long term was a much more significant effect than the effect of the electric field, because the imbibition significantly diminished the drop part above the porous surface, which diminished, in turn, the electric Maxwell stresses, which could stretch the drop. A simplified analytical model was developed to measure the moisture transport coefficient responsible for liquid imbibition in these experiments. Furthermore, the phase-field modeling of drops on balsa was used to illustrate how a change in the contact angle from hydrophobic to hydrophilic triggers drop imbibition into balsa wood.
Phase diagrams—Why they matter and how to predict them
Authors: Chew Pin Yu , Reinhardt Aleks
Published: December 2022

Understanding the thermodynamic stability and metastability of materials can help us to, for example, gauge whether crystalline polymorphs in pharmaceutical formulations are likely to be durable. It can also help us to design experimental routes to novel phases with potentially interesting properties. In this Perspective, we provide an overview of how thermodynamic phase behavior can be quantified both in computer simulations and machine-learning approaches to determine phase diagrams, as well as combinations of the two. We review the basic workflow of free-energy computations for condensed phases, including some practical implementation advice, ranging from the Frenkel–Ladd approach to thermodynamic integration and to direct-coexistence simulations. We illustrate the applications of such methods on a range of systems from materials chemistry to biological phase separation. Finally, we outline some challenges, questions, and practical applications of phase-diagram determination which we believe are likely to be possible to address in the near future using such state-of-the-art free-energy calculations, which may provide fundamental insight into separation processes using multicomponent solvents.
A novel approach to preventing SARS-CoV-2 transmission in classrooms: A numerical study
Authors: Pal Anish , Biswas Riddhideep , Pal Ritam , Sarkar Sourav , Mukhopadhyay Achintya
Published: December 2022

The education sector has suffered a catastrophic setback due to the ongoing COVID pandemic, with classrooms being closed indefinitely. The current study aims to solve the existing dilemma by examining COVID transmission inside a classroom and providing long-term sustainable solutions. In this work, a standard 5 × 3 × 5 m3 classroom is considered where 24 students are seated, accompanied by a teacher. A computational fluid dynamics simulation based on OpenFOAM is performed using a Eulerian–Lagrangian framework. Based on the stochastic dose–response framework, we have evaluated the infection risk in the classroom for two distinct cases: (i) certain students are infected and (ii) the teacher is infected. If the teacher is infected, the probability of infection could reach 100% for certain students. When certain students are infected, the maximum infection risk for a susceptible person reaches 30%. The commonly used cloth mask proves to be ineffective in providing protection against infection transmission, reducing the maximum infection probability by approximately 26% only. Another commonly used solution in the form of shields installed on desks has also failed to provide adequate protection against infection, reducing the infection risk only by 50%. Furthermore, the shields serve as a source of fomite mode of infection. Screens suspended from the ceiling, which entrap droplets, have been proposed as a novel solution that reduces the infection risk by 90% and 95% compared to the no screen scenario besides being completely devoid of fomite infection mode. The manifestation of infection risk in the domain was investigated, and it was found out that in the case of screens the maximum infection risk reached the value of only 0.2 (20% infection probability) in 1325 s.
Comparison of acoustic and hydrodynamic cavitation: Material point of view
Authors: Hofmann Julien , Thiébaut Charles , Riondet Michel , Lhuissier Pierre , Gaudion Sylvain , Fivel Marc
Published: December 2022

This study investigated the difference in mechanical response of the martensitic stainless steel X3CrNiMo13-4/S41500/CA6 NM QT780 between hydrodynamic and acoustic cavitation erosion. The results show that acoustic cavitation erosion generates small pits at a high temporal frequency on the material, while hydrodynamic cavitation erosion produces larger pits at a lower frequency. Acoustic cavitation erosion tests have been performed using a 20 kHz ultrasonic horn located at 500 μm in front of a specimen. This experimental setup, known as an indirect method, is inspired from the ASTM G32 standard. Hydrodynamic cavitation erosion tests were conducted with classic experimental conditions of a PREVERO device: a cavitation number of 0.87 corresponding to a flow velocity of 90 m s−1 and an upstream pressure of 40 bars. In addition, for a given exposure time, the percentage of surface covered by the pits is smaller for acoustic cavitation than for hydrodynamic cavitation. Three successive steps have been identified during the damage process: persistent slip bands (PSB) first appear on the surface, cracks initiate and propagate at the PSB locations and nonmetallic interfaces, and finally, parts of the matter are torn off. A careful time examination of the same small area of the exposed sample surface by scanning electron microscopy reveals that acoustic cavitation is faster to initiate damage than hydrodynamic cavitation.
Basic postulates of some coordinate transformations within material media
Authors: Weng Zi-Hua
Published: December 2022

This paper aims to explore the physical quantities of several invariants, including the basic postulates of some types of crucial coordinate transformations, conservation laws, and continuity equations, in the electromagnetic and gravitational fields. Maxwell first utilized quaternions to describe the electromagnetic theory. Subsequent scholars make use of octonions to study the physical properties of electromagnetic and gravitational fields simultaneously, including the octonion field strength, field source, angular momentum, torque, and force. When an octonion coordinate system transforms rotationally, the scalar part of one octonion will remain unchanged, although the vector part of the octonion may alter. In the octonion space O, some invariants can be derived from this octonion property. A part of these invariants can be selected as the basic postulates of Galilean transformation or Lorentz transformation. Similarly, several invariants can be derived from the octonion property in the transformed octonion space Ou, and the invariants can be chosen as the basic postulates of a few new types of coordinate transformations. Furthermore, the combination of invariants in the octonion spaces can be applied as the basic postulates of some new coordinate transformations, relevant to the norm of physical quantities. Through the analysis, it is easy to find that each conserved quantity has its preconditions from the perspective of octonion spaces. This is helpful to deepen the further understanding of the physical properties of conservation laws and other invariants.