bluuebunny/crossref_metadata_2025 huggingface dataset:
Peculiarities of implementing mechanism of circular economy in the context of sustainable development of communities
Authors: Khymynets Volodymyr , Holovka Anatolii , Tsimbolynets Ganna
Published: May 2021

The article analyzes prospects for implementing mechanisms of closed-loop economy (circular economy) at local level based on strengthening material and financial base of communities, expanding their managerial powers due to decentralization. Relevant changes in the approaches to form communities’ socio-economic sphere aimed at gradual transition to circular economy have been pointed out, as well as main priorities in the framework of such transition are identified and characterized. Main directions and measures are suggested, which are aimed at achieving resource efficiency, waste processing, using secondary raw material and minimizing environmental damage in the framework of social and economic activities. Methodological principles for the study were methods of system analysis (to analyze circular economy as holistic system of interconnected elements with specific functions), generalization (to outline main directions and applied propositions for implementing circular economy at the level), comparison (to compare linear and circular models of economy).
Importance of Technical and Professional Writing Certificate Program in a Japanese Computer Science Context
Authors: Roy Debopriyo , Yasui Banri
Published: May 2021

Technical communication (TC) as a subject, and more so a department in the university curriculum are few and far between in the Japanese educational context, even with STEM education. As part of this paper, an exploratory pilot study is described explaining the overall importance of such a TC certificate program and how an optional TC feeder course could help students understand the value of the TC and professional communication (PC) discipline for a typical Japanese computer science academic context, in preparation for the job market. Further, such a TC-focused introductory feeder course helps the university administration, students and teachers better understand how computer science as a discipline should also emphasize on technical and professional writing and communication skills in the language curriculum, for better project management, and helping students develop soft skills for the market. Further, another strong argument for such coursework (offered in English as a medium of instruction) is also related to developing students’ entrepreneurial and transition skills for the market. This paper highlighted on one such rare certificate program and feeder course in the computer science (CS) department of a Japanese technical university which helped students understand the scope of the market, how technical communication as a discipline has wide-ranging opportunities, besides helping students develop basic understanding of content areas such as manual and information design, usability, content management and delivery, technical language, visualisation etc. Finally, the paper ends with a discussion of a few of the well-known TC certificate programs and TC organizational infrastructure in the US academia, and how we can catch up with that trend in Japanese higher education.
Learning Style Index: Analysis and Smartphone-based Implementation
Authors: Homma Yuki , Hamada Mohamed
Published: May 2021

Recently, research on remote system is attracting a lot of attention due to the outbreak of infectious disease in 2019. Especially in the field of education, many instructors must deliver a lecture through the internet. However, sometimes there lacks the mutual understanding between instructors and students. In this research, we propose a mobile application to analyze the learning styles for individual learners. It provides students a tool to identify their best learning style and an efficient learning method. It also helps teachers to create suitable lecture materials by indicating the learning tendencies of their classes.
Towards Developing a Teleoperation System for a Disaster Response Robot
Authors: Manawadu Udaka A. , Ogawa Hiroaki , Shishiki Keito , Funayama Yuki , Sasaki Hiroto , Suzuki Takuma , Naruse Keitaro
Published: May 2021

Standard Disaster Robotics Challenge of World Robot Summit (WRS) aims to test the ability of robots that can be used as disaster response robots. Robot Engineering Lab of the University of Aizu is developing a robotic system to address challenges in the WRS. The competition has five stages, and the teleoperation robotic system had to be developed to satisfy the requirements of each challenge. REL uses a disaster-response robot called Giraffe, which has the capability of traveling in hard terrain. Open Robot Technology Middleware uses to integrate all of the subsystems inside the robot. Each subsystem has different tasks that process video data, RGB depth data, Point Cloud Data, sensor data and, feedback data. The Robotic system includes 6 cameras and NDI Software Developer Kit used to transmit and view video streams remotely. The video stream from each camera can be viewed separately, and it gives wider control over the robot for the operator. The teleoperation robotic system was tested during a robot demonstration held in Fukushima Robot Test Field, and results were analyzed according to the WRS 2018 competition guidelines. The results were at an acceptable level.
Large Area Inspection Using 3D Point Cloud Data in a Disaster Response Robot
Authors: Ogawa Hiroaki , Shishiki Keito , Manawadu Udaka A. , Naruse Keitaro
Published: May 2021

Large area inspection using a robot is critical in a disastrous situation; especially when humans are inhabiting the catastrophic environment. Unlike natural environments, such environments lack details. Thus, creating 3D maps and identifying objects has became a challenge. This research suggests a 3D Point Cloud Data (PCD) merging algorithm for the less textured environment, aiming World Robot Summit Standard Disaster Robotics Challenge 2021 (WRS). Spider2020, a robotic system designed by the Robot Engineering Laboratory, University of Aizu, was used in this research. Detecting QR codes in a wall and merging PCD, and generating a wall map are the two main tasks in the competition. The Zxing library was used to detect and decode QR codes, and the results were quite accurate. Since the 3D mapping environment has fewer textures, decoded QR code locations are used as the PCD mapping markers. The position of the PCD file was taken from the location given by the robotic arm in Spider2020. The accuracy of merging PCD was improved by including the position of PCD files in the merging algorithm. The robotic system can be used for Large area Inspections in a disastrous situation.
Raytracing Render Switcher with Embree
Authors: Sato Rion , Cohen Michael
Published: May 2021

We introduce a way of implementing physically-based renderers that can switch rendering methods with a raytracing library. Various physically-based rendering (PBR) methods can generate beautiful images that are close to human view of real world. However, comparison between corresponding pairs of pixels of image pairs generated by different rendering methods is necessary to verify whether the implementation correctly obeys mathematical models of PBR. For comparison, result images must be same scene, same resolution, from same camera angle. We explain fundamental theory of PBR first, and present overview of a library for PBR, Embree, developed by Intel, as a way of rendering-switchable implementation. Finally, we demonstrate computing result images by a renderer we developed. The renderer can switch rendering methods and be extended for other method implementations.
Envisioning IoT applications in a smart city to underpin an effective municipal strategy: The smartbin project
Authors: Ziouzios Dimitris , Baras Nikolaos , Dasygenis Minas , Tsanaktsidis Constantinos
Published: May 2021

Due to the Earth’s population rapid growth and the modern lifestyle, the urban waste creation rate constantly increases.Organic waste, which forms a significant part of municipal solid waste, has caused increasing environmental concerns. Recycling is the only way to make a sustainable environment. According to estimations from the United States Environmental Protection Agency, around 24 percent of the total waste can be composted. Instead, most of it is land filled and incinerated. By composting organic waste,we can preserve resources and produce a valuable by-product that can be used as a locally produced fertilizer. In this paper, we propose a solution: a low-cost and effective Smart Compost Bin that utilizes modern technologies, such as environmental sensors and the LoRaWAN protocol to assist with the compost process.A centralized Information System collects measurements from smart bins that can be deployed anywhere and can further assist with the waste collection process. We have performed several experiments with our smart bin prototype, evaluated its efficiency and concluded that it is a feasible solution.
West African Polyrhythm: culture, theory, and representation
Authors: Frishkopf Michael
Published: May 2021

In this paper I explicate polyrhythm in the context of traditional West African music, framing it within a more general theory of polyrhythm and polymeter, then compare three approaches for the visual representation of both. In contrast to their analytical separation in Western theory and practice, traditional West African music features integral connections among all the expressive arts (music, poetry, dance, and drama), and the unity of rhythm and melody (what Nzewi calls “melo-rhythm”). Focusing on the Ewe people of south-eastern Ghana, I introduce the multi-art performance type called Agbekor, highlighting its poly-melo-rhythms, and representing them in three notational systems: the well-known but culturally biased Western notation; a more neutral tabular notation, widely used in ethnomusicology but more limited in its representation of structure; and a context-free recursive grammar of my own devising, which concisely summarizes structure, at the possible cost of readability. Examples are presented, and the strengths and drawbacks of each system are assessed. While undoubtedly useful, visual representations cannot replace audio-visual recordings, much less the experience of participation in a live performance.
Umrüsten und Gas geben – Als Ergotherapeut im Autohaus
Authors: Ganter Thomas
Published: May 2021

Thomas Ganter hat einen besonderen Arbeitsplatz: ein Autohaus. Dort stellt der Ergotherapeut umgebaute Pkw für Personen zusammen, die aufgrund einer Behinderung oder Krankheit kein herkömmliches Auto nutzen können.
Familienzeit mit Kindern im Lockdown – Occupational Disruption
Authors: Hofmann Tabea , Sander Lea , Willert Lisa
Published: May 2021

In ihrer Bachelorarbeit befassten sich Tabea Hofmann, Lea Sander und Lisa Willert mit dem Freizeiterleben von Familien mit Kindern im Grundschulalter. Dabei legten sie ihren Fokus auf die Durchführung der gemeinsamen Familienfreizeit während des ersten Lockdowns der Corona-Pandemie. Sie interessierte besonders der Umgang mit der aus den Maßnahmen resultierenden Occupational Disruption.
Endlich wieder gut schlafen – Ergotherapie für eine gute Schlafhygiene
Authors: Droth Barbara , Staub Cristina
Published: May 2021

Im Schlaf erholen sich Körper und Geist, wir verarbeiten den Tag und stärken unser Abwehrsystem. Leider haben immer mehr Menschen Schwierigkeiten beim Ein- oder Durchschlafen. Hier können Ergotherapeuten ansetzen und gemeinsam mit den Betroffenen Maßnahmen für einen erholsamen Schlaf erarbeiten.
Update Breast Cancer 2021 Part 2 – Advanced Stages, Long-Term Consequences and Biomarkers
Authors: Ditsch Nina , Stickeler Elmar , Behrens Annika , Belleville Erik , Fasching Peter A. , Fehm Tanja N. , Hartkopf Andreas D. , Jackisch Christian , Janni Wolfgang , Kolberg-Liedtke Cornelia , Kolberg Hans-Christian , Lüftner Diana , Lux Michael P. , Müller Volkmar , Schneeweiss Andreas , Schütz Florian , Schulmeyer Carla E. , Tesch Hans , Thomssen Christoph , Uleer Christoph , Untch Michael , Welslau Manfred , Wöckel Achim , Wurmthaler Lena A. , Würstlein Rachel , Thill Marc , Aktas Bahriye
Published: May 2021

This review summarises and discusses significant aspects of recently published studies on patient treatment in advanced breast cancer and on biomarkers in breast cancer. In recent years, a large number of drugs for all molecular subtypes have been developed up to phase III trials. With regard to immune checkpoint inhibitors in metastasised breast cancer, the recent discussion has centred on the best candidate for combined chemotherapy. The oral taxanes could become a new type of oral chemotherapies. There is a growing body of data on biomarkers for the use of CDK4/6 inhibitors, which could also signify further development for other molecular subtypes. New substances have been developed for metastatic HER2+ breast cancer that still result in good remission even after massive prior treatment and/or cerebral metastasis. Similarly, knowledge is growing about targeted therapies with antibody-drug conjugates (ADC) against Trop-2, which could bolster our therapeutic armoury in triple-negative breast cancer (TNBC). In addition, the clinical focus is on understanding how to maintain fertility after breast cancer treatment. Here, pooled analyses provide new insights.
Iron-Driven Alterations on Red Blood Cell-Derived Microvesicles Amplify Coagulation during Hemolysis via the Intrinsic Tenase Complex
Authors: Jongerius Ilse , Zeerleder Sacha S. , Delvasto-Núñez Laura , Roem Dorina , Bakhtiari Kamran , van Mierlo Gerard , Meijers Joost C. M.
Published: May 2021

Hemolytic disorders characterized by complement-mediated intravascular hemolysis, such as autoimmune hemolytic anemia and paroxysmal nocturnal hemoglobinuria, are often complicated by life-threatening thromboembolic complications. Severe hemolytic episodes result in the release of red blood cell (RBC)-derived proinflammatory and oxidatively reactive mediators (e.g., extracellular hemoglobin, heme, and iron) into plasma. Here, we studied the role of these hemolytic mediators in coagulation activation by measuring factor Xa (FXa) and thrombin generation in the presence of RBC lysates. Our results show that hemolytic microvesicles (HMVs) formed during hemolysis stimulate thrombin generation through a mechanism involving FVIII and FIX, the so-called intrinsic tenase complex. Iron scavenging during hemolysis using deferoxamine decreased the ability of the HMVs to enhance thrombin generation. Furthermore, the addition of ferric chloride (FeCl3) to plasma propagated thrombin generation in a FVIII- and FIX-dependent manner suggesting that iron positively affects blood coagulation. Phosphatidylserine (PS) blockade using lactadherin and iron chelation using deferoxamine reduced intrinsic tenase activity in a purified system containing HMVs as source of phospholipids confirming that both PS and iron ions contribute to the procoagulant effect of the HMVs. Finally, the effects of FeCl3 and HMVs decreased in the presence of ascorbate and glutathione indicating that oxidative stress plays a role in hypercoagulability. Overall, our results provide evidence for the contribution of iron ions derived from hemolytic RBCs to thrombin generation. These findings add to our understanding of the pathogenesis of thrombosis in hemolytic diseases.
Applications of Fecal Microbiota Transplantation: Emphasis on Clostridioides difficile Infections
Authors: Signorette Juliana Peloso , Oliveira Rômulo Tadeu Dias de , Montiel José Maria , Longo Priscila Larcher
Published: May 2021

Objective This study aimed to perform a comprehensive review of clinical trials using fecal microbiota transplantation in cases of Clostridioides difficile infection.

Methods This manuscript reviews clinical studies published from 2003 to 2020 at the Scientific Electronic Library Online (SciELO Brazil), Latin American and Caribbean Health Sciences Literature (LILACS) and US National Library of Medicine (MedLine/PubMed) databases using the descriptors antibiotic/antimicrobial, Clostridium difficile/Clostridioides difficile, intestinal microbiota/intestinal microbiome and fecal transplantation.

Results Interventions on microbiota include the use of probiotics, prebiotics, and fecal microbiota transplantation as therapeutic methods. Results show that fecal microbiota transplantation is an excellent alternative for the treatment of recurrent C. difficile infections.
Hospital Admissions from the Emergency Department and Subsequent Critical Care Interventions for Influenza during Pregnancy
Authors: Krenitsky Nicole , Wen Timothy , Cham Stephanie , Venkatesh Kartik K. , Attenello Frank , Mack William J. , D'Alton Mary , Friedman Alexander M.
Published: May 2021

Objective The objectives of this study were to determine (1) whether obstetrical patients were more likely to be admitted from the emergency department (ED) for influenza compared with nonpregnant women, and (2) require critical care interventions once admitted.

Study Design Using data from the 2006 to 2011 Nationwide Emergency Department Sample, ED encounters for influenza for women aged 15 to 54 years without underlying chronic medical conditions were identified. Women were categorized as pregnant or nonpregnant using billing codes. Multivariable log linear models were fit to evaluate the relative risk of admission from the ED and the risk of intensive care unit (ICU)-level interventions including mechanical ventilation and central monitoring with pregnancy status as the exposure of interest. Measures of association were described with adjusted risk ratios (aRRs) with 95% confidence intervals (CIs).

Results We identified 15.9 million ED encounters for influenza of which 4% occurred among pregnant women. Pregnant patients with influenza were nearly three times as likely to be admitted as nonpregnant patients (aRR = 2.99, 95% CI: 2.94, 3.05). Once admitted, obstetric patients were at 72% higher risk of ICU-level interventions (aRR = 1.72, 95% CI: 1.61, 1.84). Of pregnant women admitted from the ED, 9.3% required ICU-level interventions such as mechanical ventilation or central monitoring. Older patients and those with Medicare were also at high risk of admission and ICU-level interventions (p < 0.01).

Conclusion Pregnancy confers three times the risk of admission from the ED for influenza and pregnant women are significantly more likely to require ICU-level medical interventions compared with women of similar age. These findings confirm the significant disease burden from influenza in the obstetric population and the public health importance of reducing infection risk.

Key Points
Measuring Variation in Interpregnancy Interval: Identifying Hotspots for Improvement Initiatives
Authors: Karakash Scarlett D. , Main Elliott K. , Chang Shen Chih , Shaw Gary M. , Stevenson David K. , Gould Jeffrey B.
Published: May 2021

Objective The study aimed to determine if single year birth certificate data can be used to identify regional and hospital variation in rates of short interpregnancy interval (IPI < 6 months).

Study Design IPI was estimated for multiparous women ages 15 to 44 years with singleton live births between 2015 and 2016. Perinatal outcomes, place of birth, maternal race, and data for IPI calculations were obtained by using birth certificates. IPI frequencies are presented as observed rates.

Results The cohort included 562,039 multiparous women. Short IPI rates were similar to those obtained with analyses by using linked longitudinal data and confirmed the association with preterm birth. Short IPI rates varied by race and Hispanic nativity. There was substantial hospital (0.8–9%) and regional (2.9–6.2%) variation in short IPI rates.

Conclusion IPI rates can be reliably obtained from current year birth certificate data. This can be a useful tool for quality improvement projects targeting interventions and rapidly assessing their progress to promote optimal birth spacing.

Key Points
The Association between the Number of Vacuum Pop-Offs and Adverse Neonatal Outcomes
Authors: Sakowicz Allie , Zahalka Salwa J. , Miller Emily S.
Published: May 2021

Objective Obstetrical vacuum manufacturers have long recommended a maximum of two to three pop-offs be allowed before abandoning the procedure. However, there is a paucity of evidence on the safety of vacuum-assisted vaginal delivery in relation to the number of pop-offs to support this recommendation. Our objective was to examine whether the number of pop-offs in a vacuum-assisted vaginal delivery was associated with adverse neonatal outcomes.

Study Design This is a retrospective cohort study of women who underwent a trial of a vacuum-assisted vaginal delivery at a single tertiary care institution between October 2005 and June 2014. Maternal and fetal factors associated with the number of pop-offs were examined in bivariable analyses. Multivariable analyses were performed to determine the independent association of the number of pop-offs with adverse neonatal outcomes.

Results Of the 1,730 women who met inclusion criteria, 1,293 (74.7%) had no pop-offs, 240 (13.9%) had one pop-off, 128 (7.4%) had two pop-offs, and 69 (4.0%) had three or more pop-offs. Neonatal scalp/facial lacerations, intracranial hemorrhage, seizures, central nervous system depression, and neonatal intensive care unit admission were all associated with the number of pop-offs in bivariable analyses. In multivariable analyses, compared to no pop-offs, having any vacuum pop-offs was associated with an increased odds of adverse neonatal outcomes. However, there was not a consistent dose–response relationship.

Conclusion While having vacuum pop-offs in a vacuum-assisted vaginal delivery was associated with an increased risk of adverse neonatal outcomes, there did not appear to be a dose-dependent association with the number of pop-offs.

Key Points
Sleep among Obstetrics and Gynecology Trainees: Results from a Yoga-Based Wellness Initiative
Authors: Babbar Shilpa , Williams Karen B. , Cheng An-Lin
Published: May 2021

Objective This study aimed to determine the feasibility of using a wrist-based fitness tracking device to assess sleep among Obstetrics and Gynecology (OBGYN) trainees who engaged in a yoga-based wellness program. We also sought to evaluate the effects of yoga on sleep.

Study Design A quality improvement initiative consisting of an 8-week wellness program of weekly yoga classes, nutrition, and physical challenges was implemented for OBGYN residents and Maternal–Fetal Medicine fellows. The Polar A370 fitness tracker device was provided and synced to the Polar Flow for Coach program for inclusion. Data obtained included total and restful sleep from each night the device were worn. Pre- and post-assessment of the Pittsburg Sleep Quality Index (PSQI) were compared. Linear mixed models were used to estimate and test the effect of yoga on sleep while controlling for on-call shifts.

Results Of the 15 participants who synced their device, 13 (87%) were included for analysis. Sleep data from 572 nights were analyzed. The mean (SD) total sleep was 434.28 (110.03) minutes over the 8 weeks. A minimum of 7 hours (420 minutes) of total sleep occurred 59.3% of the time. After controlling for Friday or Saturday night on-call, those who attended yoga class had a significantly greater total sleep (yoga: 425.14 minutes [41.89], no yoga: 357.33 [43.04] minutes; p = 0.04). There was no significant change in the mean global PSQI score after the program (pre: 5.0 [1.6], post: 5.1 [2.5], p = 0.35).

Conclusion Wearable fitness monitors provide insight into sleep patterns displayed during training and can serve as a tool to identify those who are sleep deprived and assist in the evaluation of trainee wellness. Training programs are encouraged to provide access to yoga and mindfulness interventions to improve sleep and possibly clinical performance.

Key Points
Zentrallager von Asklepios: Versorgung auf neuem Niveau
Authors: Lang Michael
Published: May 2021

Die Asklepios Kliniken errichten zurzeit ihr neues Zentrallager in Bad Oldesloe. Nach der Fertigstellung soll es nicht nur die eigenen Einrichtungen, sondern auch Krankenhäuser außerhalb des Konzerns,Arztpraxen und den Consumerbereich mit medizinischen Produkten beliefern.
Blow up criterion for the 2D full compressible Navier–Stokes equations involving temperature in critical spaces
Authors: Fan Jie , Jiu Quansen , Wang Yanqing , Xiao Yuelong
Published: May 2021

In this paper, we derive some new blow up criterion for the 2D full compressible Navier–Stokes equations in terms of the density and the temperature in critical spaces. This is an improvement of corresponding results obtained by Wang and Zhang [Appl. Math. Comput. 232, 719–726 (2014)].
Local well-posedness for the isentropic compressible MHD system with vacuum
Authors: Fan Jishan , Zhou Yong
Published: May 2021

In this work, we prove the local well-posedness of strong solutions to the isentropic compressible magnetohydrodynamics system with vacuum in a bounded domain Ω⊂R3.
Two oscillation states in free/hard bilayered nano-pillars
Authors: Yuan X. , Lu Z. , Zhang Z. , Cheng M. , Liu J. , Wang D. , Xiong R
Published: May 2021

The magnetization oscillation driven by spin transfer torque (STT) in a nano-pillar composed of a large in-plane anisotropy fixed layer and a soft free layer is studied. It is found that instead of frequency continuously changing with current as most nano-oscillators do, this kind of nano-oscillator can only oscillate in two stable states with specific frequencies. In each state, the frequency is almost invariant with current density. The oscillation state could be easily manipulated by the magnetization state of the free layer or an applied pulse magnetic field as the working current density is lower than a critical value (Jc). The critical current density and the frequency difference of the two states can be tuned by the saturation magnetization (Ms) of the two layers and the anisotropy constant K of fixed layer. Phase-locked oscillation is obtained in a two-nanopillar system, suggesting that it may be possible to amplify the oscillation signal by building an array of this kind of nanopillar system. This kind of STT-based nano-oscillator may have various applications in the field of spintronics.
Waiting-time dependent non-equilibrium phase diagram of simple glass- and gel-forming liquids
Authors: Zepeda-López Jesús Benigno , Medina-Noyola Magdaleno
Published: May 2021

Under numerous circumstances, many soft and hard materials are present in a puzzling wealth of non-equilibrium amorphous states, whose properties are not stationary and depend on preparation. They are often summarized in unconventional “phase diagrams” that exhibit new “phases” and/or “transitions” in which time, however, is an essential variable. This work proposes a solution to the problem of theoretically defining and predicting these non-equilibrium phases and their time-evolving phase diagrams, given the underlying molecular interactions. We demonstrate that these non-equilibrium phases and the corresponding non-stationary (i.e., aging) phase diagrams can indeed be defined and predicted using the kinetic perspective of a novel non-equilibrium statistical mechanical theory of irreversible processes. This is illustrated with the theoretical description of the transient process of dynamic arrest into non-equilibrium amorphous solid phases of an instantaneously quenched simple model fluid involving repulsive hard-sphere plus attractive square well pair interactions.
Existence and multiplicity of solutions for logarithmic Schrödinger equations with potential
Authors: Shuai Wei
Published: May 2021

We study the logarithmic Schrödinger equation with the sign-changing potential function. It is known that the corresponding functional is not well defined in H1(RN), but by imposing some condition on V(x), we can show that the functional is well defined in a subspace of H1(RN). Then, the existence and multiplicity of solutions is obtained by using variational methods. We remark that the existence of solutions is deeply influenced by the sign of Q(x).
A broadband acoustic panel based on double-layer membrane-type metamaterials
Authors: Nguyen Huy , Wu Qian , Chen Jiaji , Yu Yukai , Chen Hui , Tracy Sharon , Huang Guoliang
Published: May 2021

Low-frequency noise is a growing problem in large structures of modern transportation technologies. In this study, we report a large-scale acoustic panel made of double-layer membrane-type metamaterials (DMAMs) for broadband noise reduction. A complete theoretical model based on the unit cell is fully developed and extended for finite multi-celled membrane-type acoustic metamaterial (MAMs) array. A large-scale acoustic panel constructed from 8 × 8 DMAM unit cells is proposed. To deal with the global compliance of the large-scale support structure, the double-layer panel frame structure with large bending stiffness is designed to shift the global resonances to higher frequencies and provide an efficient way to well maintain the MAM's performance. Moreover, the double-layer configuration further guarantees ultra high transmission loss within the frequency range of interest. Experiments are carried out to validate the analytical and numerical predictions. Excellent transmission loss ranging from 20 to 59 dB within ten third octave bands (0.32–2.5 kHz) is observed, deeply breaking the mass density law. We believe the proposed design and the associated theoretical model could serve as an efficient tool for designing acoustic metamaterial-based panels and soundproof walls with high noise reduction in low/middle frequency regions.
Radiographic areal density measurements on the OMEGA EP laser system
Authors: Stan Camelia V. , Saunders Alison M. , Hill Matthew P. , Lockard Tom , Mackay Kyle , Ali Suzanne J. M. , Rudd Robert E. , McNaney James , Eggert Jon , Park Hye-Sook
Published: May 2021

We describe two orthogonal radiography geometries at the OMEGA EP laser facility, which we refer to as side-on and face-on radiography. This setup can be used to determine quantitative information about the areal densities in solid, particulate, or liquid samples. We show sample images from these two different platforms that use the radiography diagnostic, one of material microjetting by the Richtmeyer–Meshkov instability and one of a deforming tin sample by the Rayleigh–Taylor instability, demonstrating the versatile applicability of such measurements in the field of high-energy density physics. The analytical methodology behind the quantitative Rayleigh–Taylor face-on radiography is also demonstrated and can be applied to other types of samples.
On exactly self-similar turbulent boundary layers and single-layer scaling
Authors: Patwardhan Saurabh S. , Ramesh O. N.
Published: May 2021

Turbulent boundary layers are traditionally thought to obey two layer scaling. However, it was shown by Dixit and Ramesh [J. Fluid Mech. 615, 445–475 (2008)] that the so-called sink flow turbulent boundary layer obeys a Blasius-like scaling all through the boundary layer. We make this single layer scaling as an operational definition for perfectly equilibrium flow and derive equations for a general class of equilibrium flows with permeable walls allowing suction and blowing of fluid. Using the above definition, constraints required to be satisfied by such equilibrium turbulent boundary layers are derived and discussed in detail. Using direct numerical simulations (DNS), we demonstrate the existence of such turbulent boundary layers, and various properties of these boundary layers are studied in detail. In particular, it is shown that the mean velocity profiles and other turbulent statistics display excellent similarity, and various boundary layer parameters in such boundary layers vary systematically with the magnitude of blowing/suction parameter. By extension, it is also demonstrated by DNS that higher order moments (up to third order moments) also display streamwise self-similarity. We believe that this is an important result where self-similarity is demonstrated for the first time for higher moments of fluctuating velocity. The non-universality of the log-law coefficients in favorable pressure gradient flows is already known [S. A. Dixit and O. N. Ramesh, J. Fluid Mech. 615, 445–475 (2008) and Chauhan et al., in Proceedings of 11th EUROMECH European Turbulence Conference on Turbulence, Porto, Portugal (Springer Proceedings in Physics, 2007), pp. 239–241]. We demonstrate their non-universal nature in equilibrium boundary layers with suction and blowing using the present direct numerical simulations. Remarkably, the ratio of Reynolds shear stress (u′v′¯) to streamwise (u′2¯) and spanwise turbulent intensity (w′2¯) in these boundary layers is constant over the log-region in the mean velocity profile even though u′2¯, w′2¯, and u′v′¯ by themselves show variation with y+ in the log region, indicative of the absence of inactive motion in these flows. It is shown that the dominance of active motion and more importantly the absence of inactive motion leads to a universality of scaling that manifests as a single layer Blasius scaling with self-similarity in such flows. Equivalently, it could also be seen as a single layer scaling with all variables all through the boundary layer. This would mean that the friction velocity scales the entire boundary layer, which could be taken to suggest equivalence of attached eddies with the active component of motion.
Microscopic electroelastic modeling of a spin transition with symmetry breaking
Authors: Slimani Ahmed , Boukheddaden Kamel
Published: May 2021

A theoretical approach combining Monte-Carlo and molecular-dynamics techniques is developed to deal with the structural anisotropy upon the spin transition in molecular materials. The simulations were done on a 2D lattice, where the cells have two structural symmetries: square-shaped (non-degenerated) at a low spin (LS) state and a diamond-shaped (degenerated) at a high spin (HS) state. We investigated the thermally induced spin transition and the relaxation of a metastable HS state trapped at low temperatures. We demonstrated that the structural parameters have a crucial impact on the spin transition, and by adjusting the lattice and the elastic parameters, we were able to generate a two-step thermally induced spin transition. The analysis of magnetic and structural properties pointed out that the symmetry breaking reduces significantly the cooperativity between the lattice’s cells. The maps of the difference between cell diagonals reveal an auto-organized HS lattice with an alternation of different symmetries over the state, confirming the symmetry breaking when switching from an LS to HS state. The mechanical relaxation of an LS lattice containing HS defects shows an anisotropic distribution of the elastic energy, channelized over the shortest paths toward the borders of the lattice. The interaction between two HS defects placed in a LS lattice is as well investigated as a function of their separating distance for different symmetries of the HS state. We demonstrated that the HS symmetry impacts the HS/LS elastic barrier as well as the dependence of the relaxed elastic energy on the distance separating two HS defects introduced in an LS lattice.
Functional bionanomaterials for cell surface engineering in cancer immunotherapy
Authors: Ma Sheng , Xu Yudi , Song Wantong
Published: May 2021

The cell surface is the forward position in cancer immunotherapy, with surface ligand and receptor interactions between various cells for determining immune privilege or recognition. Therefore, cell surface engineering (CSE) that manipulates the surface interactions between the immune effector cells (IECs) and tumor cells represents a promising means for eliciting effective anticancer immunity. Specifically, taking advantage of the development in biomaterials and nanotechnology, the use of functional bionanomaterials for CSE is attracting more and more attention in recent years. Rationally designed functional biomaterials have been applied to construct artificial functional modules on the surface of cells through genetic engineering, metabolic labeling, chemical conjugation, hydrophobic insertion, and many other means, and the CSE process can be performed both ex vivo and in vivo, on either IECs or tumor cells, and results in enhanced anticancer immunity and various new cancer immunity paradigms. In this review, we will summarize the recent exciting progresses made in the application of functional bionanomaterials for CSE especially in establishing effective recognition and interaction between IECs and tumor cells.
Inverse design of a Helmholtz resonator based low-frequency acoustic absorber using deep neural network
Authors: Mahesh K. , Kumar Ranjith S. , Mini R. S.
Published: May 2021

The design of low-frequency sound absorbers with broadband absorption characteristics and optimized dimensions is a pressing research problem in engineering acoustics. In this work, a deep neural network based inverse prediction mechanism is proposed to geometrically design a Helmholtz resonator (HR) based acoustic absorber for low-frequency absorption. Analytically obtained frequency response from electro-acoustic theory is deployed to create the large dataset required for training and testing the deep neural network. The trained convolutional neural network inversely speculates optimum design parameters corresponding to the desired absorption characteristics with high fidelity. To validate, the inverse design procedure is initially implemented on a standard HR based sound absorber model with high accuracy. Thereafter, the inverse design strategy is extended to forecast the optimum geometric parameters of an absorber with complex features, which is realized using HRs and a micro-perforated panel. Subsequently, a quasi-perfect low-frequency acoustic absorber having minimum thickness and broadband characteristics is deduced. Importantly, it is demonstrated that the proposed absorber, comprising four parallel HRs and a microperforated panel, absorbed more than 90% sound in the frequency band of 347–630 Hz. The introduced design process reveals a wide variety of applications in engineering acoustics as it is suitable for tailoring any sound absorber model with desirable features.
Behavior of synchronous and asynchronous spatially oscillating planar liquid jets in tandem
Authors: Arote Ashish , Bade Mukund , Banerjee Jyotirmay
Published: May 2021

Understanding the behavior of oscillating liquid jets in tandem is vital for improving the efficacy of numerous industrial applications. An interpretation of their behavior in the terms of development, associated instability, and interactions when used in tandem remains unclear. Therefore, the present study reports the numerical investigations on spatially oscillating liquid jets in tandem. Numerical simulations are carried out by solving Navier–Stokes equations coupled with volume of fluid method to track the air–water interface. The development of the tandem jets, growth in amplitude of oscillation, and interaction between the coherent structures is analyzed for both synchronous and asynchronous liquid jets in tandem. Moreover, the effect of nozzle spacing on these parameters is also reported in the present study. It is demonstrated that a decrease in the nozzle spacing destabilizes these jets and promotes an early merging between them. This decrease in nozzle spacing also improves the stream-wise entrainment of the surrounding fluid. Furthermore, synchronous jets are found to be more stable as compared to asynchronous jets owing to a relatively constant spacing between the two jets. Asynchronous jets provide better fluid entrainment than synchronous jets owing to their higher amplitude of oscillation and stronger jet front interactions. Moreover, it is demonstrated that these interactions at the jet front give rise to a staggered vortex front in asynchronous jets, whereas the vortex front remains symmetric in synchronous jets.
Direct CVD growth of MoS2 on chemically and thermally reduced graphene oxide nanosheets for improved photoresponse
Authors: Fan Huacheng , Wang Jia , Li Xiya , You Hui , Li Xinzhe , Pei Chengjie , Huang Xiao , Li Hai
Published: May 2021

The direct chemical vapor deposition (CVD) of transition metal dichalcogenides (TMDCs) on graphene or graphene oxide (GO) allows for the scalable production of van der Waals heterostructures (vdWHs). Herein, considering that the CVD growth of TMDCs depends largely on the surface property of the substrate, we compared chemically reduced GO (CrGO) and thermally reduced GO (TrGO) as substrates to induce the CVD growth of MoS2 without a seeding promoter. On monolayer (1L) to three-layer CrGO and TrGO nanosheets, more triangular MoS2 flakes were found on CrGO than on TrGO. This is because CrGO with less surface defects could promote the growth of MoS2 as compared to TrGO, which normally carries more defects. Such a difference was not obvious when the thickness of CrGO and TrGO nanosheets exceeded five layer. As a demonstration, the obtained MoS2@1L-CrGO and MoS2@1L-TrGO vdWH nanosheets showed much higher photosensitivities as compared to the 1L CrGO and TrGO nanosheets under both the blue and red laser irradiation. In particular, MoS2@1L-CrGO with a higher density of MoS2 showed larger photosensitivity than MoS2@1L-TrGO. In addition, rolling up the MoS2@1L-CrGO and MoS2@1L-TrGO vdWH nanosheets into MoS2@CrGO and MoS2@TrGO vdWH nanoscrolls further enhanced their photosensitivities, largely due to the presence of multiple vdWH interfaces in the scrolled structure. Our work demonstrates that the reduction in surface defects of chemically modified graphene oxide promotes the deposition of MoS2 to form vdWHs and related scroll structures, which are promising for optoelectronics and flexible electronics.
Plasma parameters in very high frequency argon plasmas mixed with nitrogen at atmospheric pressure
Authors: Yasutake Kiyoshi , Yoshida Kazushi , Ohmi Hiromasa , Kakiuchi Hiroaki
Published: May 2021

A recently reported procedure [Yoshida et al., J. Appl. Phys. 128, 133303 (2020)] for estimating plasma parameters in atmospheric-pressure (AP) Ar plasma has been extended to be applicable for Ar-N2 AP plasma. Amplitudes of current density and voltage between the electrodes and power absorbed in the plasma have been obtained by three-dimensional computer simulation of the whole system. The only needed input parameters for the simulation are input power and capacitance gaps in the matching unit. Using an inhomogeneous plasma model and a power balance relation, the central electron density (n0) and the collisional energy loss per electron–ion pair created (ɛc) have been estimated. In this study, to estimate the average electron temperature (Te), ɛc as a function of Te has been calculated from the cross-sectional data set on electron impact reactions in the range applicable for the present plasma condition. In the low Te range (<1 eV) where ɛc has not been well reported, we have calculated ɛc(Te) as a function of N2 concentration in Ar taking the vibrational and rotational excitations of N2 molecules into account. From the experiments and analyses of Ar-N2 AP plasma generation, it is found that n0 decreases drastically with increasing N2 concentration while Te increases slightly. Also, it is found that n0 increases with increasing input power (P) such as n0∝P1.9 while Te increases gradually. Based on the N2 concentration and input power dependences of Te and n0, some guidelines for selecting effective AP plasma nitridation conditions have been discussed.
A high-order implicit least square-based finite difference-finite volume method for incompressible flows on unstructured grids
Authors: Liu Y. Y. , Shu C. , Zhang H. W. , Yang L. M.
Published: May 2021

In this study, a high-order implicit least squares-based finite difference-finite volume (ILSFD-FV) method with a lattice Boltzmann flux solver is presented for the simulation of two-dimensional incompressible flows on unstructured grids. In this method, a high-order polynomial based on Taylor series expansion is applied within each control cell, where the unknown spatial derivatives at each cell center are approximated by the least squares-based finite difference scheme. The volume integral of the high-order polynomial over the control cell results in a pre-multiplied coefficient matrix in the time-dependent term. This makes the high-order method be implicit in nature. With this feature, a high-order implicit Runge–Kutta time integration scheme, namely, the explicit first-stage singly diagonally implicit Runge–Kutta (ESDIRK) scheme, is applied to obtain the time-accurate solutions for flow problems. The non-linear system of equations arising from each ESDIRK stage except for the first explicit stage is solved by a dual time stepping approach. A matrix-free lower-upper symmetric Gauss–Seidel solver is then used to efficiently march the solution in the pseudo time. The present high-order ILSFD-FV method is verified and validated by both steady and unsteady 2D incompressible flow problems. Numerical results indicate that the developed implicit method outperforms its explicit counterpart in terms of the convergence property and computational efficiency. The speedup ratio of the computational effort is about 3–22.
Distinguishing different excitation pathways in two-dimensional terahertz-infrared-visible spectroscopy
Authors: Vietze Laura , Backus Ellen H. G. , Bonn Mischa , Grechko Maksim
Published: May 2021

In condensed molecular matter, low-frequency modes (LFMs) associated with specific molecular motions are excited at room temperature and determine essential physical and chemical properties of materials. LFMs, with typical mode energies of up to ∼500 cm−1 (62 meV), contribute significantly to thermodynamic parameters and functions (e.g., heat capacity and entropy) and constitute the basis for room temperature molecular dynamics (e.g., conformational fluctuations and change). LFMs are often analyzed indirectly by the measurement of their effect on specific high-frequency modes (HFMs); the LFM–HFM coupling is reflected in the lineshape, as well as in the spectral and angular diffusion of the HFM. Two-dimensional terahertz-infrared-visible (2D TIRV) spectroscopy allows measuring the LFM–HFM coupling directly and can thereby provide new insights into the strength and nature of the coupling and the character of LFMs. However, the interference between the different signals generated by different excitation pathways can complicate 2D TIRV spectra, preventing a straightforward analysis. Here, we develop an experimental method to distinguish different excitation pathways in 2D TIRV spectroscopy and plot them separately in different quadrants of a 2D spectrum. We validate this method by measuring the spectra of CaF2 and nitrogen gas. For CaF2, only sum-frequency mixing between infrared and terahertz fields generates the signal. In contrast, for N2, only difference-frequency mixing is observed. We then use this method to separate sum- and difference-frequency pathways in the 2D TIRV spectrum of liquid water, verifying the previous interpretation of the lineshape of the 2D TIRV spectrum of water.
Single-photon detection in the mid-infrared up to 10 μm wavelength using tungsten silicide superconducting nanowire detectors
Authors: Verma V. B. , Korzh B. , Walter A. B. , Lita A. E. , Briggs R. M. , Colangelo M. , Zhai Y. , Wollman E. E. , Beyer A. D. , Allmaras J. P. , Vora H. , Zhu D. , Schmidt E. , Kozorezov A. G. , Berggren K. K. , Mirin R. P. , Nam S. W. , Shaw M. D.
Published: May 2021

We developed superconducting nanowire single-photon detectors based on tungsten silicide, which show saturated internal detection efficiency up to a wavelength of 10 μm. These detectors are promising for applications in the mid-infrared requiring sub-nanosecond timing, ultra-high gain stability, low dark counts, and high efficiency, such as chemical sensing, LIDAR, dark matter searches, and exoplanet spectroscopy.