bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved Production of Large and Multi-Directional Homogeneous Optical Glass: SCHOTT N-BK7®for Challenging Applications
Authors: Rupp Fabian , Jedamzik Ralf , Dietrich Volker , Petzold Uwe
Published: October 2022

In many applications, the spatial refractive index variation – called homogeneity – within a measurement aperture either in one or two directions is important. Typical application examples are prisms in ultra-precision metrology with stability in multiple directions. Large lenses are used in artificial laser guide star systems for atmospheric correction in large telescopes. The challenge of enabling highest refractive index homogeneities requires tight control of all production steps from melting to hot forming and fine annealing. Large optical formats can be produced as singular castings in moulds up to 1.2 m in diameter and 250 mm thickness. Smaller formats are available as blocks produced in dimensions of approx. 250 x 250 x 180 mm3. A more economic and ecologic way is the production of continuous strips of glass up to approx. 500 mm width and 120 mm thickness. Recently SCHOTT has improved the homogeneity of these continuously produced jumbo strips significantly. Now homogeneity of up to H4 quality (2 ppm index maximum variation) can be provided on apertures up to approx. 900 mm x 500 mm. This paper gives an insight overview on the latest results and current state of this topic at the optical glass manufacturer SCHOTT.
3D printed FBG based sensor for vital signal monitoring – Influence of the infill printing parameters
Authors: Ferreira Alexandra , Tavares Cátia , Leitão Cátia , Lo Presti Daniela , Domingues M. Fátima , Alberto Nélia , da Silva Hugo Plácido , Antunes Paulo
Published: October 2022

The fused deposition modelling technique has been used in the production of strain sensors in which fibre Bragg gratings (FBGs) are encapsulated during the 3D printing process. This paper reports the study of the influence of the FBG position and the material filling, in this case a flexible polymer material, on the sensors’ sensitivity and overall performance. In addition, this study preliminarily evaluated the ability of the strain sensor to monitor (heart rate) HR and (respiratory rate) RR as a wearable on the wrist and as a non-intrusive solution on the back of an office chair.
Figure of Merit Comparison Between Surface Plasmon Resonance and Bloch Surface Waves
Authors: Dias Bernardo , de Almeida José M. M. , Coelho Luís C. C.
Published: October 2022

The sensing performance of two types of electromagnetic surface waves are compared, a Surface Plasmon Polariton, where a gold thin film is used, being a standard material in biosensing applications; and a Bloch Surface Wave, using a photonic crystal made of a stack of silica and titanium dioxide layers. It is verified that the sensing performance (as measured by the Figure of Merit) of the gold film is higher, even though the Bloch Surface Waves can serve specific applications due to its narrow bandwidth. At the same time, it is concluded that further research must be made in order to choose the right set of parameters that maximize the Bloch Surface Wave performance.
Influence of displacement gradients on laser speckle photography
Authors: León Schweickhardt , Andreas Tausendfreund , Dirk Stöbener , Andreas Fischer
Published: October 2022

The influence of first and second order displacement gradients on laser speckle photography is investigated in a simulative study that is supported with experimental data. The systematic error is found to scale linearly with the second order gradient, while the random error scales with the first order gradient. The gradient-based error dominates the uncertainty budget of an in-process measurement during single tooth milling close to the machined surface.
Tapered hollow-core photonic crystal fibers
Authors: Gérôme Frédéric , Osório Jonas H. , Amrani Foued , Debord Benoit , Benabid Fetah
Published: October 2022

In this communication, we will first review the recent advances of hollow-core photonic crystal fibers. Then, the possibility offered to tailor their optical properties by making tapers will be discussed.
Retracted Article: Study and development of an optical waveguide cap for biomedical application
Authors: Ferreira Margarida , Monteiro Catarina S. , Henriques Patrícia C. , Gonçalves Inês C. , Frazão Orlando
Published: October 2022

This paper has been formally retracted because it has been accidentally published the volume. Request approved by the proceedings Editor and the Publisher on October 24, 2022.
Comparison of simulation and experimental characterization of a 4-pass diode-pumped 4-active-mirrors 1053 nm laser amplifier
Authors: Hamoudi Thomas , Chesneau Hugo , Dubé Thomas , Dubois Emma , Lamy Manon , Maunier Cédric , Braud Alain , Meroni Cesare , Camy Patrice , Montant Sébastien
Published: October 2022

In this paper, we will discuss the performances of a 4-pass diode-pumped 4-active-mirrors laser amplifier. Numerical simulations along with experimental characterization paves the way to reach 1 J at 10 Hz pulse rate at 1053 nm. Both Nd :glass and Nd :Lu :CaF2 amplifier medium performances will be compared in this amplifier.
Analysis of defects on machined surfaces of aluminum alloy (Al 7075) using imaging and topographical techniques
Authors: Dahnel Aishah Najiah , Ghani Muhamad Ali Abdul , Raof Natasha A. , Mokhtar Suhaily , Khairussaleh Nor Khairusshima Muhamad
Published: October 2022

Aluminum alloys 7075 (Al 7075) are widely used for various industrial components in which machining operations are often conducted during their manufacturing process. However, the machining operations could introduce defects on the machined surfaces of the components which will be carried over and may lead to either issues in the subsequent fabrication process or failure during the products' service life. This study investigates the machined surface's defects of Al 7075 underwent drilling operations using imaging and topographical techniques which include optical microscope, scanning electron microscope and 3D surface profiler. Surface roughness was analysed with respect to the surface defects to investigate the correlation between the roughness parameters and topographical features of the machined surfaces. The defects found on the machined surfaces of Al 7075 are microcrack, adhesion, feed mark and burr. Surface roughness was found to be highly influenced by topographical features particularly feed mark. Thus, in addition to measuring the roughness, inspection through imaging and 3D topographic techniques is important for analyzing the surface characteristic in order to determine the defects, hence deducing the detailed surface features and deformation caused by the drilling operations.
The dependence of speckle contrast on velocity: a numerical study
Authors: van As Kevin , Simons Bram A. , Kleijn Chris R. , Kenjeres Sasa , Bhattacharya Nandini
Published: October 2022

We study how the speckle contrast depends on scatterer velocity, with the goal of further developing laser speckle imaging as a quantitative measurement technique. To that end, we perform interferometric computer simulations on a dilute plug flow. The results of our numerical experiment, that we compare with known analytical expressions to confirm their veracity, match well at low velocities with the Gaussian expression. Finally, we address the issue of how velocity depends on speckle decorrelation time, and show that the speckle size is most likely the relevant connecting length scale.
Les multiples facettes du vieillissement : Nous n’avons pas que l’âge de nos artères
Authors: Henrard Jean-Claude
Published: October 2022

L’image dominante de la personne vieillissante est limitée à sa seule composante biologique,
et la vieillesse devient synonyme de maladie et de dépendance. Parallèlement, le
vieillissement de la population est rendu responsable de l’augmentation d’une grande partie
des dépenses de soins. Cette vision n’est-elle pas réductrice ? Nous souhaitons ici la
compléter en situant le vieillissement dans un ensemble de processus individuels et
collectifs qui se déroulent tout au long du parcours de vie. Analyser les relations complexes
entre vieillissement et santé permet de mieux comprendre les déterminants de la santé au
grand âge, et de mettre en œuvre des interventions les plus efficaces possibles.
Les différentes facettes des crises sanitaires
Authors: Gilbert Claude
Published: October 2022

Drame du sang contaminé, crise de la vache folle, plusieurs crises ont fait vaciller le système
de santé français à la fin du XXe siècle. Divers types d’analyses existent pour décrire le
phénomène des crises sanitaires. On peut les voir comme le produit de dysfonctionnements dans
la gestion des risques sanitaires, ayant par la suite un retentissement social et politique, ou
au contraire comme étant avant tout la conséquence de dynamiques sociales et politiques
initiées par des acteurs extérieurs au champ de la Santé Publique. Certaines crises peuvent
également être lues comme révélatrices de jeux de pouvoirs impliquant des acteurs du champ
même de la Santé Publique. La multiplicité de ces angles de vue montre qu’il n’est pas aisé de
décrire avec un modèle unique ce que l’on entend par « crise sanitaire ».
Lutter contre l’obésité en gouvernant les conduites des consommateurs
Authors: Bergeron Henri , Castel Patrick , Nouguez Étienne
Published: October 2022

Si, en France, le rôle des facteurs socio-structurels a été souligné au cours de la mise sur agenda1
du problème de l’obésité et du surpoids, les dispositifs déployés ont surtout visé à responsabiliser les
individus. Cette politique est en cela représentative des transformations que connaissent les pays
occidentaux, où l’on observe le déploiement de dispositifs qui visent à résoudre des problèmes publics
par le gouvernement des conduites des individus, pensés comme des consommateurs. Le cas de
l’obésité permet de souligner trois caractéristiques de ce mode de gouvernement. 1) Il tend à s’appuyer
sur des disciplines qui lui offrent une légitimation théorique et des instruments « politiquement
praticables ». 2) Il n’est pas le seul fait de l’État mais repose sur une nébuleuse d’acteurs (municipalités,
associations, industriels, chercheurs…). 3) Il s’appuie volontiers, comme l’a suggéré Foucault, sur les
dynamiques autonomes qui animent les entités individuelles ou collectives pour mieux les gouverner.
Environnement et santé : la combinatoire des expositions
Authors: Barouki Robert
Published: October 2022

L’exposome représente l’ensemble des expositions couvrant la vie entière qui peuvent influencer la
santé humaine. Il comprend les expositions physiques extérieures, le contexte psycho-social et les
régulations du milieu intérieur. Ce nouveau concept englobe l’ensemble des facteurs de risque d’origine
non génétique. De nouvelles méthodologies à large spectre (les « omiques ») permettent d’aborder, du
moins partiellement, les différentes composantes de l’exposome. À titre d’illustration, l’étude des effets
toxiques de tous les mélanges possibles de tous les produits chimiques de notre environnement n’est
pas faisable de manière systématique. En revanche, si l’on aborde la question d’un point de vue
mécanistique, le nombre de voies de toxicité biologiques est beaucoup plus limité et il est envisageable
d’étudier les interactions entre ces différentes voies. Dans tous les cas de figure, il s’agit d’un grand
défi scientifique pour les années à venir.
Mise en place d’un outil pédagogique de documentation du processus de conception architecturale
Authors: Calixte Xaviera , Cuffi Karine , Leclercq Pierre
Published: October 2022

Cet article aborde la notion de documentation de projet mis en place dans le cadre pédagogique particulier. Aujourd’hui, les agences d’architecture et d’ingénierie mettent en place des protocoles de travail pour garder et transmettre une série d’informations capitales pour la bonne concrétisation du projet. Toutefois, nous constatons que cette approche est inexistante dans le contexte pédagogique où les objectifs sont ciblés à une phase précise de l’évolution du projet. Pourtant, il est important de conscientiser les futurs acteurs du domaine au travail d’équipe, à la communication du projet et aux différentes natures de l’information (graphique, de synthèse, documentation, etc.). Pour sensibiliser nos étudiants à cette problématique, nous avons articulé et connecté autour d’un énoncé commun les cours de deux institutions différentes : l’atelier d’architecture de master de l’Université de Liège et le projet d’ingénierie du bâtiment de l’IMT Mines Alès. Nous appuyons notre discussion, d’une part sur un état des pratiques existantes dans les ateliers d’architecture et, d’autre part, le retour de plus 5 ans d’expérience dans cette collaboration particulière.
Une approche didactique des outils BIM au service de la durabilité : vers une conception écologique numériquement assistée
Authors: Siala Aida , Halin Gilles , Bani Abdelwaheb
Published: October 2022

La compétence en Simulations de la Performance Energétique (SPE) est un atout fondamental pour un architecte. Être capable de lire des résultats de simulation et d’adapter sa conception en conséquence est devenu une capacité essentielle chez les architectes diplômés. Cependant, enseigner la SPE aux étudiants peut être difficile, souvent en raison de la complexité des logiciels et des méthodes, mais aussi de la multitude des informations qui entrent en jeu. Afin de sensibiliser au rôle des outils BIM dans l’amélioration de la performance énergétique, cet article propose et expérimente une approche d’optimisation simplifiée basée sur trois différentes méthodes de simulation. L’expérimentation de ces méthodes a démontré leur capacité à guider la prise de décision vers une conception plus performante et plus respectueuse de son environnement et a suggéré une expérimentation future plus globale de l’approche proposée.
Algorithme génétique ou automate cellulaire : le cas d’une optimisation multicritère sous contraintes pour la conception d’une enveloppe
Authors: Duclos-Prévet Claire , Guéna François , Efron Mariano
Published: October 2022

Il existe différentes méthodes génératives qui permettent une conception performancielle. Les algorithmes génétiques apparaissent comme la solution la plus populaire dans la littérature scientifique. Néanmoins, en pratique, les problèmes rencontrés nécessitent souvent une intégration de contraintes strictes que d’autres techniques génératives fonctionnant avec des règles, comme les automates cellulaires, sont plus aptes à intégrer. Dans cette étude, nous comparons l’efficacité de ces deux techniques appliquées à un même cas d’étude issu de la pratique professionnelle. Il s’agit de la conception d’une enveloppe pour une tour de bureaux à Madagascar qui intègre à la fois le confort thermique et la qualité de vue. Il ressort de cette expérience que l’approche la plus efficace est une méthode hybride qui utilise à la fois un automate cellulaire pour intégrer les contraintes, et un algorithme génétique conduisant l’optimisation multicritère.
Quality Initiative to Reduce Failed Trial of Labor after Cesarean Using Calculated VBAC Success Likelihood
Authors: Williams Frank B. , Pierce Hayley , McBride Carole A. , DeAngelis Justin , McLean Kelley
Published: October 2022

Objective Vaginal birth after cesarean can reduce morbidity associated with multiple cesarean deliveries. Failed vaginal birth after cesarean is associated with increased maternal and neonatal morbidity. The Maternal-Fetal Medicine Units Vaginal Birth After Cesarean calculator is a validated tool to predict the likelihood of successful trial of labor after cesarean. Predicted likelihood < 60% has been associated with increased maternal and neonatal morbidity. We sought to determine if formal incorporation of calculated vaginal birth after cesarean likelihood into patient-centered counseling would reduce failed vaginal birth after cesarean.

Study Design This is a quality improvement intervention at a single tertiary-care academic medical center, in which standardized patient counseling was implemented, facilitated by an electronic medical record template featuring patient-specific likelihood of vaginal birth after cesarean success. Term singleton pregnancies with history of one to two cesareans were included; those with contraindication to labor were excluded. Historical controls (January 2016–December 2018, n = 693) were compared with a postimplementation cohort (January 2019–April 2020, n = 328). Primary outcome was failed vaginal birth after cesarean.

Results Fewer patients in the postintervention cohort had a history of an arrest disorder (PRE: 48%, 330/693 vs. POST: 40%, 130/326, p = 0.03); demographics were otherwise similar, including the proportion of patients with <60% likelihood of success (PRE: 39%, 267/693, vs. POST: 38%, 125/326). Following implementation, induction of labor in patients with a <60% likelihood of successful vaginal birth after cesarean decreased from 17% (45/267) to 5% (6/125, p < 0.01). The proportion of failed vaginal birth after cesarean decreased from 33% (107/329) to 22% (32/143, p = 0.04). Overall vaginal birth after cesarean rate did not change (PRE: 32%, 222/693, vs. POST: 34%, 111/326, p = 0.52).

Conclusion An intervention targeting provider counseling that included a validated vaginal birth after cesarean success likelihood was associated with decreased risk of failed trial of labor after cesarean without affecting overall vaginal birth after cesarean rate.

Key Points
Bridged Peptide Analogue of RA-VII, an Antitumor Bicyclic Hexapeptide
Authors: Hitotsuyanagi Yukio , Hinosawa Taka-aki , Nakagawa Yoshie , Ito Sho , Lee Ji-Ean , Hasuda Tomoyo
Published: October 2022

A bridged peptide analogue of RA-VII was designed, in which the α carbons of residues 1 and 4 were linked by a tetramethylene chain to restrict the conformational freedom of the backbone of the 18-membered cyclopeptide. This peptide analogue was synthesized by a ring-closing metathesis reaction of [l-2-allylglycine-1, l-2-allylglycine-4]RA-VII and a subsequent hydrogenation of the resulting olefinic compound. Compared with RA-VII, the analogue showed much weaker cytotoxic activity toward human promyelocytic leukemia HL-60 cells and human colon carcinoma HCT-116 cells, which may be accounted for by the difference in the orientation of the Tyr-6 phenyl ring plane between the analogue and RA-VII.
Padronização de modelo animal para o estudo da necrose isquêmica da cabeça femoral na doença de Legg-Calvé-Perthes
Authors: Miashiro Edson Hidenori , Zanella Luis Francisco , Cardoso Guilherme Schiess , Silva Gislene dos Santos , de Angelis Kauana , de Almeida Silvio Henrique Maia
Published: October 2022

Objetivo Testar um modelo experimental para necrose isquêmica da cabeça femoral na doença de Legg-Calvé-Perthes avaliando a marcha, exames de imagens e morfohistologia.

Métodos Operaram-se 11 leitões. Induziu-se a necrose por cerclagem no colo femoral direito. Dividiram-se os leitões em grupo A com 8 animais, sacrificando-se dois na 2ª, 4ª, 6ª e 8ª semanas, respectivamente; e grupo B, com 2 animais (sham), submetidos ao procedimento cirúrgico sem a cerclagem do colo femoral direito. A classificação da marcha utilizada foi a de Etterlin. Os fêmures congelados foram submetidos à radiografia digital e tomografia computadorizada. Mediram-se a altura e largura da epífise e o coeficiente epifisário nos tempos de estudo. Realizou-se, microscopia de luz e imunohistoquímica com TGF-β1.

Resultados Um animal morreu por sepse no grupo A. Neste grupo, observou-se claudicação em todos os animais. Na radiografia digital e tomografia computadorizada observaram-se: esclerose óssea, alargamento do colo femoral direito, achatamento, colapso e fragmentação da cabeça femoral direita. Todos os valores da altura da epífise e coeficiente epifisário da cabeça femoral direita foram menores que os contralaterais, nos quais observaram-se condrócitos desordenados e separados por lacunas. Observou-se redução da expressão do TGF-β1 com 2 e 6 semanas nas cabeças femorais direitas e nas esquerdas com oito. No grupo B, não ocorreram sinais de necrose e a marcha foi normal.

Conclusões O modelo apresentado reproduziu a necrose macroscopicamente, na radiografia digital, tomografia computadorizada e microscopia. A avaliação da marcha demonstrou boa correlação com os demais achados de isquemia.

Nível de Evidência V. Estudos diagnósticos.
Hipervigilância postural e percepção da postura correta sentada em indivíduos com e sem dor lombar
Authors: de Oliveira Eduardo Lima , Coutinho Paula Fernanda Ferreira , Braga Uiara Martins , Barsante Leonardo Drumond
Published: October 2022

Objetivos Verificar se há diferença na hipervigilância postural sentada em indivíduos com e sem dor lombar. Além disso, observar se há diferença na percepção da postura correta sentada entre indivíduos com dor lombar e sem dor lombar.

Métodos O presente estudo possui delineamento observacional transversal, como tamanho amostral de 92 indivíduos, posteriormente divididos igualmente em dois grupos (com dor lombar e sem dor lombar). Foram utilizados dois instrumentos: a escala de hipervigilância para analisar a frequência que voluntários corrigem a postura sentada no dia; e o quadro de posturas para investigar a percepção dos voluntários sobre a postura correta sentada. Os dados foram submetidos ao teste de Normalidade de Shapiro-Wilk. Para comparar os valores da Escala de Hipervigilância foi utilizado o teste de Mann-Whitney e o teste Qui-quadrado e exato de Fisher para avaliação da postura correta sentada.

Resultados Não houve diferença significativa entre a hipervigilância postural sentada entre indivíduos com dor lombar e sem dor lombar. Não houve diferença significativa entre a escolha da postura correta sentada entre o grupo de indivíduos com e sem dor lombar.

Conclusão Não há diferença entre a escolha da postura correta sentada e quantidade de hipervigilância postural em indivíduos com ou sem dor lombar.
Was It a Case of “Flatbush Diabetes” with Severe Hypertriglyceridemia?
Authors: Al-Nuaimi Mouza Mohammed , Ismail Mohamed Milad , Elhouni Ali
Published: October 2022

We present a case of a morbidly obese 27 years male patient who was admitted with sudden onset abdominal pain and crashed into diabetic ketoacidosis as new-onset diabetes and discuss the possible etiology of this combined picture of acute pancreatitis and severe hypertriglyceridemia. Flatbush diabetes was, meanwhile, thought of due to his morbid obesity that in turn raised our suspicion of acute insulin-requiring type 2 diabetes mellitus versus T1 diabetes mellitus. Ketosis-prone diabetes or Flatbush diabetes is a syndrome in which diabetes commences with ketoacidosis in patients who are glutamic acid decarboxylase and antiislet cell antibody negative and have no known precipitating causes. They are usually middle-aged, overweight, or mildly obese, and in many reports, they are likely to be male with a family history of type 2 diabetes mellitus; they present with new-onset severe hyperglycemia and ketosis or frank diabetic ketoacidosis. After intensive initial insulin therapy, many patients become insulin-independent and can be well controlled on diet plus oral medications or, more rarely, diet alone.
Ramadan Fasting in Health and Disease in 2021: A Narrative Review
Authors: Hassan-Beck Reem , Hafidh Khadija , Badi Amal , Dougman Khaled , Karmo Mazn , Mir Ruqqia , Beshyah Salem A.
Published: October 2022

Introduction: The literature on the health aspects of Ramadan fasting (RF) is widely spread in many journals.

Materials and Methods: This is a narrative review of data obtained from the PubMed database (National Library of Medicine, Bethesda, Maryland, United States). We used the search term “Ramadan fasting,” and relevant records were examined. The publications are narrated thematically.

Results: The publications spanned fundamental, clinical, professional, cultural, and advocacy facets. The publications crossed conventional disciplinary lines and geographical locations and appeared in journals with different access systems. The contents are presented under the themes that emerged depending on the retrieved literature. This year basic coverage included changes in physiology and nutrition during Ramadan. However, the clinical issues included a wide range of topics. These included the impact of RF on nonalcoholic fatty liver disease and adjustments needed in endocrine replacement therapy for hypothyroidism and adrenal insufficiency. Coverage also included chronic kidney disease. The impact on maternal health, fetal well-being, and long-term effects of RF exposures were addressed in several studies. Studies in cardiovascular medicine focused on blood pressure and cardiovascular risk factors. Sports medicine and athletes' well-being received somewhat prominent coverage. The impact on renal function, particularly in patients with chronic kidney disease, was investigated by a few authors. Several groups addressed the eyes' structure and function, neurological conditions, especially headache disorders, and hematological and oncological conditions. Finally, the impact of RF on several aspects of mental health and well-being was addressed by various groups.

Conclusions: Health aspects of RF received a sustained academic interest with a broad spectrum in 2021. This narration provides an overview of the year's scholarly health-related literature on various aspects of health and disease. It should help researchers and clinicians catch up quickly with the health concerns during Ramadan.
Algebraic derivation of the energy eigenvalues for the quantum oscillator defined on the sphere and the hyperbolic plane
Authors: Srivastava Atulit , Soni S. K.
Published: October 2022

We give an algebraic derivation of eigenvalues of energy of a quantum harmonic oscillator on the surface of constant curvature, i.e., on the sphere or on the hyperbolic plane. We use the method proposed by Daskaloyannis [J. Math. Phys. 42, 1100–1119 (2001)] for fixing the energy eigenvalues of two-dimensional quadratically superintegrable systems by assuming that they are determined by the existence of a finite-dimensional representation of the polynomial algebra of motion integral operators. The tool for realizing representations is the deformed parafermionic oscillator. The eigenvalues of energy are calculated, and the result derived by us algebraically agrees with the known energy eigenvalues calculated by using classical analytical methods. This assertion, which is the main result of this article, is demonstrated by a detailed presentation. We also discuss the qualitative difference of the energy spectra on the sphere and on the hyperbolic plane.
Theory of asymmetric and piezotronically modified double Schottky barriers
Authors: Kaufmann Benjamin , Supancic Peter
Published: October 2022

We present a theoretical model for double Schottky barriers at zinc oxide grain boundaries that accounts for piezotronically modified barrier heights resulting in generally asymmetric current–voltage (I–V) characteristics with respect to the applied electrical field direction. The model is based on charge distributions in the vicinity of the barrier and its related electrical potential distributions and can be considered as a generalization of the famous model of Blatter and Greuter. The natural asymmetry of current with respect to forward and reverse bias can be explained by different grain orientations and donor densities. The previously experimentally found change of I–V curves due to the application of mechanical loads can be reproduced via the piezotronic effect, leading to changes in the barrier potential profile due to piezoelectrically induced surface charges. Also, the I–V characteristics of degraded grain boundaries can be interpreted in terms of asymmetric changes in the donor densities. In addition, a second approach is presented that is able to explain experimental data of asymmetric I–V curves of wide grain boundaries with different surface terminations (O and Zn-polar).
Theoretical and experimental research on valve-less piezoelectric pump with arc-shaped tubes
Authors: Yan Qiufeng , Yin Yongkang , Wang Le , Wang Hongmei , Sun Wanting
Published: October 2022

In order to apply a valve-less piezoelectric pump in navigation equipment, this work first revealed a valve-less piezoelectric pump with arc-shaped tubes and then researched the relationship between the main structural parameters of arc-shaped tubes and the output flow rate. According to the velocity difference between clockwise and counterclockwise directions of liquid in circular arc-shaped tubes, the flow characteristics of liquid in circular arc-shaped tubes are analyzed in this paper, and the velocity difference model and flow equation of a piezoelectric pump are established. By using three-dimensional printing technology, five types of prototypes with different parameters were made, and the experimental research was carried out. The results show that at the optimal frequency, the pump output flow is the largest. The output flow is proportional to the driving voltage, the base circle radius, and the cross section area of the pipe. The low-cost and miniaturized navigation equipment made by using the piezoelectric pump has potential application value in unmanned aerial vehicle and intelligent vehicle navigation.
Planar laser induced fluorescence mapping of a carbon laser produced plasma
Authors: Dorst R. S. , Constantin C. G. , Schaeffer D. B. , Pilgram J. J. , Niemann C.
Published: October 2022

We present measurements of ion velocity distribution profiles obtained by laser induced fluorescence (LIF) on an explosive laser produced plasma. The spatiotemporal evolution of the resulting carbon ion velocity distribution was mapped by scanning through the Doppler-shifted absorption wavelengths using a tunable, diode-pumped laser. The acquisition of these data was facilitated by the high repetition rate capability of the ablation laser (1 Hz), which allowed for the accumulation of thousands of laser shots in short experimental times. By varying the intensity of the LIF beam, we were able to explore the effects of fluorescence power against the laser irradiance in the context of evaluating the saturation vs the non-saturation regime. The small size of the LIF beam led to high spatial resolution of the measurement compared to other ion velocity distribution measurement techniques, while the fast-gate operation mode of the camera detector enabled the measurement of the relevant electron transitions.
Lattice Boltzmann very large eddy simulations of a turbulent flow over covered and uncovered cavities
Authors: Mourão Bento Hugo F. , VanDercreek Colin P. , Avallone Francesco , Ragni Daniele , Snellen Mirjam
Published: October 2022

Microphone measurements in a closed test section wind tunnel are affected by turbulent boundary layer (TBL) pressure fluctuations. These fluctuations are mitigated by placing the microphones at the bottom of cavities, usually covered with a thin, acoustically transparent material. Prior experiments showed that the cavity geometry affects the propagation of TBL pressure fluctuations toward the bottom. However, the relationship between the cavity geometry and the flowfield within the cavity is not well understood. Therefore, a very large-eddy simulation was performed using the lattice Boltzmann method. A cylindrical, a countersunk and a conical cavity are simulated with and without a fine wire-cloth cover, which is modeled as a porous medium governed by Darcy's law. Adding a countersink to an uncovered cylindrical cavity is found to mitigate the transport of turbulent structures across the bottom by shifting the recirculation pattern away from the cavity bottom. Covering the cavities nearly eliminates this source of hydrodynamic pressure fluctuations. The eddies within the boundary layer, which convect over the cover, generate a primarily acoustic pressure field inside the cavities and thus suggesting that the pressure fluctuations within covered cavities can be modeled acoustically. As the cavity diameter increases compared to the eddies' integral length scale, the amount of energy in the cut-off modes increases with respect to the cut-on modes. Since cut-off modes decay as they propagate into the cavity, more attenuation is seen. The results are in agreement with experimental evidence.
Time-resolved near backscatter imaging system on Laser MegaJoule
Authors: Trauchessec V. , Drouet V. , Chollet C. , Cornet P. , Masclet-Gobin I. , Chardavoine S. , Prunet P. , Duchastenier W. , Diaz R. , Le Deroff L. , Wrobel R. , Depierreux S.
Published: October 2022

The newly operating near-backscattering imaging (NBI) system on the Laser MegaJoule (LMJ) is briefly described with emphasis on the temporally resolved measurements and their synchronization with the LMJ laser pulse through target shots taken as part of the diagnostic commissioning campaign. The NBI measures the stimulated Brillouin and Raman scattered light around two quadruplets (one inner and one outer) of the upper LMJ hemisphere. The temporal resolution is achieved with a unique system: a specifically designed wide-open optical lens images 40 points of a diffuser onto an array of optical fibers with the scattered light recorded on a multiplexed photodiode array.
Strong electro-optic effect in Mg incorporated ZnO thin films
Authors: Yuan X. , Yamada T. , Meng L.
Published: October 2022

a-axis oriented ZnMgO epitaxial thin films with a strong linear electro-optic (EO) effect were developed by radio frequency magnetron sputtering. The Mg incorporation into ZnO thin films not only obviously increases the transmittance at the wavelength range of 400–800 nm but also reduces the leakage current by 3–6 orders of magnitude. Furthermore, with the increase in the Mg content, the linear EO response enhances significantly. In particular, the derived effective EO coefficient rc of the Zn0.72Mg0.28O thin film is (7.6 ± 0.2) pm/V, which is over three times larger than the reported values for ZnO-based thin films and over twice larger than that of ZnO single crystals. The results and discussion conclude that an enhanced intrinsic contribution can be responsible for the increase in rc with Mg incorporation. These findings open the way for the ZnO-based thin films to EO devices in optical communication and optical interconnects.
Water-tolerant solid polymer electrolyte with high ion-conductivity for simplified battery manufacturing in air surroundings
Authors: Liu Jie , Zhang Lifang , Cao Yufeng , Wang Zhenkang , Xia Xinyao , Zhou Jinqiu , Shen Xiaowei , Zhou Xi , Qian Tao , Yan Chenglin
Published: October 2022

The humidity-sensitive electrolytes necessitate the stringent conditions of lithium battery manufacturing and, thus, increase the fabrication complexity and cost. We herein report a water-tolerant solid polymer electrolyte (WT-SPE) with high Li+ conductivity (2.08 × 10−4 S cm−1 at room temperature) and electrochemically stable window (up to 4.7 V vs Li/Li+), which utilizes moisture to initiate rapid polymerization and form dense structures to achieve a facile battery manufacturing in humid air without the need of a glovebox. Molecular dynamics simulations attribute this hydrophobic behavior to the hindered transfer of a water molecule in dense WT-SPE. A stable SEI layer composed of a polymeric framework and other organic/inorganic small molecular compounds contributes to the sustainable operation of batteries. As a result, the Li|WT-SPE|LiCoO2 cells manufactured in the air exhibit a high initial capacity of 192 mA h g−1 at 0.1C and an excellent capacity retention for 300 cycles at 1C. The great advantage significantly simplifies the battery assembly process in air environment and can also maintain good interfacial contact between an electrolyte and electrodes thanks to in situ initiated polymerization, which shows great superiority and promise in the alternatives of traditional liquid and polymer electrolytes for low-cost and facile fabrication of batteries in ambient atmosphere.
Numerical investigation of a propeller operating under different inflow conditions
Authors: Wang Lianzhou , Luo Wanzhen , Li Mijian
Published: October 2022

This work investigates the flow physics in propeller wakes to better understand how propeller wakes evolve under different inflow conditions from near field to far field. A rotating propeller is numerically modeled by using a dynamic overset technique that involves the improved delayed detached-eddy simulation method. To validate the numerical approach, its results are compared against experimentally determined thrust and torque coefficients and flow fields. The results show that, compared with uniform inflow, turbulent inflow significantly modifies the morphology of the vortex system behind the propeller. Under turbulent-inflow conditions, turbulent structures appear around the boundary layer of the propeller blades and interact with the boundary layer flow of the propeller blades, leading to instability and diffusion of primary tip vortices shed by the blade tips. Multiple local pairing in the circumferential direction leads to the rapid breakdown of the tip vortex system, accompanied by the generation of numerous secondary vortex structures. Tip vortices quickly lose coherence in the middle field and far field and tend to be homogeneously distributed when there is inflow turbulence. The present study gives a deeper insight into the flow physics driving the tip vortex pairing process for a propeller operating under uniform- and turbulent-inflow conditions.
Tunable, strain-controlled nanoporous phosphorene membrane for highly efficient and selective H2/CH4 and H2/CO2 sieving: A combined molecular dynamics simulation and density functional theory study
Authors: Duan Mengru , Zeng Shuming , Gu Zonglin
Published: October 2022

Using a combined approach of molecular dynamics simulation and density functional theory, we develop a phosphorene nanopore to realize the tunable H2 sieving from mixtures with CH4 or CO2 via introducing the in-plane tensile strain. Our results show that 0%–10% strains exerted on the phosphorene membrane ensures a fast permeation of H2 while completely prohibiting the passage of CH4, demonstrating high efficiency and selectivity. Thanks to the outstanding mechanical flexibility of phosphorene, the strain tension can be utilized to easily control the pore size by which the permeance speed of H2 can be controlled in real time. However, all strained pores allow the passage of CO2, indicating a weaker strain regulation for H2/CO2 sieving by the phosphorene pore. Density functional theory calculations further confirm that the transport of H2 is energetically more favorable than CH4 and CO2 to traverse all phosphorene pores. Our findings exploit a flexible phosphorene membrane for real-time tunable H2/CH4 separation by controlling the in-plane strain.
Numerical investigation of micro-droplets mixing in electrowetting-on-dielectric digital microfluidics: The merging process and frequency response
Authors: Wei Yaming , Zou Jianfeng , Zhou Chenglin , Li Feng , Zhao Ziting
Published: October 2022

In this study, we numerically investigate the mixing of two sessile micro-droplets in open electrowetting-on-dielectric (EWOD) digital microfluidics. The mixing process is composed of the merging and the subsequent oscillation process achieved by applying alternating voltage (AC voltage) to the droplet with desired frequency and amplitude. The numerical results show excellent agreement with previous numerical and experimental studies. The focus of this study is probing into the effects of the merging process on the subsequent AC voltage-actuated oscillation of the droplet. It is observed that the merging process breaks the azimuthal symmetry of the droplet and, hence, introduces the sectoral mode to the subsequent AC voltage-actuated oscillation. The frequency dependence of the enhancement and dissipation of the sectoral oscillation is quantitatively investigated. Furthermore, the sectoral oscillation inherited from the merging process is confirmed to have little impact on the zonal oscillation of the droplet. The oscillation-based mixing enhancement of the droplet is numerically verified.
Control and mitigation of microwave crosstalk effect with superconducting qubits
Authors: Wang Ruixia , Zhao Peng , Jin Yirong , Yu Haifeng
Published: October 2022

Improving gate performance is vital for scalable quantum computing. Universal quantum computing also requires gate fidelity to reach a high level. For a superconducting quantum processor, which operates in the microwave band, the single-qubit gates are usually realized with microwave driving. The crosstalk between microwave pulses is a non-negligible error source. In this article, we propose an error mitigation scheme to address this crosstalk issue for single-qubit gates. There are three steps in our method. First, by controlling the detuning between qubits, the microwave induced classical crosstalk error can be constrained within the computational subspace. Second, by applying the general decomposition procedure, the arbitrary single-qubit gate can be decomposed as a sequence of X and virtual Z gates. Finally, by optimizing the parameters in virtual Z gates, the error constrained in the computational space can be corrected. Using our method, no additional compensation signals are needed, arbitrary single-qubit gate time will not be prolonged, and the circuit depth containing simultaneous single-qubit gates will also not increase. The simulation results show that, in a specific regime of qubit–qubit detuning, the infidelities of simultaneous single-qubit gates can be as low as that without microwave crosstalk.
Investigation of hemocompatibility and vortical structures for a centrifugal blood pump based on large-eddy simulation
Authors: Liu Yangwei , Xie Nan , Tang Yumeng , Zhang Yan
Published: October 2022

The evolution of complex flow structures has a large impact on the hemocompatibility of the centrifugal blood pump. In this study, the hemodynamic performance and the hemocompatibility of a centrifugal blood pump are investigated based on large-eddy simulation (LES). Comparisons are conducted between the LES results and the results predicted by the renormalization group (RNG) k−ε model and delayed detached eddy simulation (DDES) methods. The local trace criterion is utilized to analyze the vortical structures within the blood pump. Results show that the tip leakage vortex, the Taylor–Couette flow, and the flow separation are the most important flow structures in the blood pump. These structures have a significant influence on the hemodynamic performance and hemocompatibility. Quantitative comparison between the hemodynamic performance and the hemocompatibility is conducted between DDES, RNG k−ε, and LES results. Little difference is shown between DDES and LES results, while the RNG k−ε model tends to underestimate the pressure and hemolysis due to adopting the steady-state approach, and the assumption of isotropy and equilibrium turbulence transport. In detail, the accuracy of RANS in predicting the strength of the main vortical structures is insufficient, which tends to underestimate the leakage vortex strength and overestimate the Taylor vortex strength. Furthermore, an analysis of the relationship between hemocompatibility and vortical structures indicates that the interaction between the boundary layer and the vortical structures, such as leakage vortex and Taylor vortex, induces more blood damage, while the blood damage caused by vortical structures in the mainstream is limited.
Coupled charge and energy transfer dynamics in light harvesting complexes from a hybrid hierarchical equations of motion approach
Authors: Fay Thomas P. , Limmer David T.
Published: October 2022

We describe a method for simulating exciton dynamics in protein–pigment complexes, including effects from charge transfer as well as fluorescence. The method combines the hierarchical equations of motion, which are used to describe quantum dynamics of excitons, and the Nakajima–Zwanzig quantum master equation, which is used to describe slower charge transfer processes. We study the charge transfer quenching in light harvesting complex II, a protein postulated to control non-photochemical quenching in many plant species. Using our hybrid approach, we find good agreement between our calculation and experimental measurements of the excitation lifetime. Furthermore, our calculations reveal that the exciton energy funnel plays an important role in determining quenching efficiency, a conclusion we expect to extend to other proteins that perform protective excitation quenching. This also highlights the need for simulation methods that properly account for the interplay of exciton dynamics and charge transfer processes.
Migration and rheotaxis of elliptical squirmers in a Poiseuille flow
Authors: Liu Chen , Ouyang Zhenyu , Lin Jianzhong
Published: October 2022

The migration and rheotaxis of elliptical squirmers (a swimmer self-propels by imposing a given tangential velocity at its surface) in a Poiseuille flow are simulated numerically. The phase diagrams are employed to illustrate the effect of the aspect ratio (AR=0.2–1.0) and the Reynolds number of the squirmer (Rep=0.05–4.0), the self-propelling strength (β=−11 to 9), and the blockage ratio (κ=0.09–0.25) on the stable movement and orientation evolution of the elliptical squirmers. Five typical migration modes (including the stable sliding, periodic tumbling, damped swinging, periodic swimming, and chaotic migrating modes) and three rheotaxis states (including the stable, sub-stable, and unstable states) are identified. This pattern also exists for the locomotion of a pair of squirmers. It is found that, with increasing |β| and β≥5 or β≤−11 and κ≥0.21, the squirmers migrate in the more stable modes and rheotaxis states. With increasing Rep (Rep≥2.5), this pattern can also be found when the locomotion of two squirmers is considered, but it shows the opposite effect for an individual squirmer. In addition, a squirmer with a smaller AR is more easily to be trapped by the sidewall with yeq/H=0.18, θeq/π=1.5 because it is difficult to orient. Accordingly, a larger AR yields a migration, which is more easily along the centerline of the flow with yeq/H=0.5, θeq/π=1.0. It is interesting that the squirmers with AR = 0.2 almost maintain upstream oriented as they are usually attracted by the sidewall.
Instability mechanisms of thermocapillary liquid bridges between disks of unequal radii
Authors: Li Hao , Zeng Zhong , Zhang Liangqi , Liu Hao , Liu Yong , Wang Yue , Xiao Yao , Yin Linmao
Published: October 2022

In this paper, we explore thermocapillary liquid bridges between two disks of unequal radii with Prandtl numbers Pr of 0.0258 (mercury) and 0.068 (gallium arsenide) to gain insight into the underlying instability mechanism. In the context of Legendre's spectral element method, we determine critical conditions via linear stability analysis and then identify the instability mechanism through energy analysis. For the mercury bridge (Pr = 0.0258), our analysis suggests that the flow instability undergoes an oscillatory bifurcation for radius ratios in the range of 0.5 ≤ Γr ≤ 0.66. In particular, we found three transitions between two-dimensional steady axisymmetric flow and three-dimensional stationary flow by further increasing the radius ratio to 0.73 ≤ Γr ≤ 0.76. For the gallium arsenide liquid bridge (Pr = 0.068), the instability is always an oscillatory bifurcation in the whole computational interval. Furthermore, our observations identify six instability modes with different mechanisms. All instability modes in the mercury bridge (Pr = 0.0258) are purely hydrodynamic, but the thermocapillary mechanism cannot be ignored in the gallium arsenide liquid bridge (Pr = 0.068) because of the enhanced Pr effect.