bluuebunny/crossref_metadata_2025 huggingface dataset:
Performances des coopératives agricoles innovantes : le cas de la valorisation de la figue de Barbarie par Nopaltec en Algérie
Authors: Boumali Noure El Imene , Mamine Fateh , Cheriet Foued , Montaigne Etienne
Published: January 2023

Cette étude met en lumière l’impact de l’innovation sur l’orientation-marché et les performances d’une coopérative de valorisation des coproduits du figuier de barbarie en Algérie. Alors que la question des performances de l’entreprenariat collectif a été largement débattue, elle l’a été beaucoup moins pour des coopératives innovantes. Dans ce travail, nous mettons l’accent sur les performances de ce modèle d’entreprenariat fondé sur la réappropriation d’innovations techniques. Dans ce sens, notre analyse cherche à étendre la recherche empirique antérieure sur les performances des coopératives agricoles en introduisant l’orientation vers le marché et une évaluation plus globale des performances socioéconomiques des coopératives innovantes comme Nopaltec. Nos résultats portant sur les « autres » performances – rôle dans l’appropriation collective et la diffusion de l’innovation, structuration de la filière, fonctions socio-politique et territoriale de la coopérative – plaident pour une lecture élargie des performances des structures coopératives agricoles.
CHICADE nuclear facility: a collaborative technological platform, dedicated to the expertise and characterisation of nuclear wastes
Authors: David Olivier , Carre Dominique , Genin Mathieu , Vigneau Olivier
Published: January 2023

CHICADE (CHimie CAractérisation DEchets – Chemistry CAracterization Wastes) is one of the nuclear facilities of the Energy Division of the French Alternative Energies and Atomic Energy Commission (CEA/DES). The CEA/DES is responsible for structuring and piloting the research programmes on energy at CEA. It involves its own institutes of research and those of other divisions. CHICADE is part of the Directorate for Nuclear Dismantling, Services and Waste Management. The Laboratory of Expertise and Destructive characterization is set up in the Basic Nuclear Facility – N° 156 called “CHICADE” where heavy equipment is used. The laboratory brings together both skills and means of characterization, using destructive methods on nuclear waste packages. It also carries out measurements on the whole waste package (gas release measurements, leaching tests). After a short presentation of the CEA and the Cadarache Centre, this publication aims to present the CHICADE facility and present the types of expertise on nuclear waste that are conducted there, i.e., measurement of the diffusion coefficient, inventories, leaching test, permeability measurement, gas measurements, radiochemistry, imaging. In conclusion, CHICADE is a nuclear facility with unique equipment, allowing exhaustive expertise to be carried out in a single location, benefiting from cross and complementary methods.
Judging Urgency in 343 Ectopic Pregnancies Prior to Surgery – The Importance of Transvaginal Sonographic Diagnosis of Intraabdominal Free Blood
Authors: Pape Janna , Bajka Anahita , Seifert Burkhardt , Asmis Lars , Imesch Patrick , Metzler Julian , Burkhardt Tilo , Condous George , Samartzis Eleftherios Pierre , Bajka Michael
Published: January 2023

Objectives Assessing urgency in ectopic pregnancies (ECP) remains controversial since the disorder covers a large clinical spectrum. Severe conditions such as acute abdomen or hemodynamic instability are mostly related to intra-abdominal blood loss diagnosed as free fluid (FF) on transvaginal sonography (TVS). The aims of the current study were to investigate the value of FF and to assess other potentially predictive parameters for judging urgency.

Methods Retrospective cohort analysis on prospectively collected cases of proven ECP (n = 343). Demographics, clinical and laboratory parameters, and findings on TVS and laparoscopy (LSC) were extracted from the digital patient file. FF on TVS and free blood (FB) in LSC were evaluated. Low urgency was defined as FB (LSC) < 100 ml and high urgency as FB (LSC) ≥ 300 ml. The best subset of variables for the prediction of FB was selected and predictors of urgency were evaluated using receiver operator characteristic (ROC) curves.

Results Clinical symptoms, age, β-HCG, hemoglobin (HB) preoperative, and FF were examined in multivariate analysis for the cutoff values of 100 ml and 300 ml. FF was the only independent predictor for low and high urgency; HB preoperative was only significant for high urgency offering marginal improvement. ROC analysis revealed FF as an excellent discriminatory parameter for defining low (AUC 0.837, 95% CI 0.794–0.879) and high urgency (AUC 0.902, 95 % CI 0.860–0.945).

Conclusion Single assessment of FF on TVS is most valuable for judging urgency. However, the exact cutoff values for a low- and high-risk situation must still be defined.
Quality Control of Nitrogen Multiple Breath Washout in a Multicenter
Pediatric Asthma Study
Authors: Nitsche Catharina , Frauchiger Bettina Sarah , Thiele Dominik , Oestreich Marc-Alexander , Husstedt Berrit Liselotte , Grychtol Ruth Margarethe , Maison Nicole , Foth Svenja , Meyer Meike , Jakobs Nikolas , Bahmer Thomas , Hansen Gesine , von Mutius Erika , Kopp Matthias
Published: January 2023

Background Nitrogen multiple breath washout (N2MBW) is a lung function
test increasingly used in small airway diseases. Quality criteria have not yet
been globally implemented and time-consuming retrospective overreading is
necessary. Little data has been published on children with recurrent wheeze or
asthma from multicentered studies.

Methods Children with wheeze or asthma and healthy controls were included
in the longitudinal All Age Asthma Cohort (ALLIANCE). To assess ventilation
inhomogeneity, N2MBW tests were performed in five centers from 2013 until 2020.
All N2MBW tests were centrally overread by one center. Multiple washout
procedures (trials) at the visit concluded to one test occasion. Tests were
accepted if trials were technically sound (started correctly, terminated
correctly, no leak, regular breathing pattern) and repeatable within one test
occasion. Signal misalignment was retrospectively corrected. Factors that may
impact test quality were analyzed, such as experience level.

Results N2MBW tests of n=561 participants were analyzed leading to
n=949 (68.3%) valid tests of n=1,390 in total.
Inter-center test acceptability ranged from 27.6% to 77.8%.
End-of-test criterion and leak were identified to be the most common reasons for
rejection. Data loss and uncorrectable signal misalignment led to rejection of
58% of trials in one center. In preschool children, significant
improvement of test acceptability was found longitudinally
(χ2(8)=18.6; p=0.02).

Conclusion N2MBW is feasible in a multicenter asthma study in children.
However, the quality of this time-consuming procedure is dependent on experience
level of staff in preschool children and still requires retrospective
overreading for all age groups.
Frontal Sinus Mucosa Bacteriological Features: Evaluation after Unintentional Opening in Neurosurgery
Authors: Sato Hiroki , Ooigawa Hidetoshi , Suzuki Kaima , Yanagawa Taro , Lepic Milan , Otsuka Munehiro , Fushihara Goji , Kurita Hiroki
Published: January 2023

Objectives The bacteriological features of the frontal sinus mucosa may impose significant complications in neurosurgery, when breached unintentionally. This study aimed to investigate the bacterial flora in patients undergoing frontal craniotomy for cerebrovascular substrate surgery.

Design This is a single-center prospective study.

Setting When mucosal laceration occurred, the patients underwent frontal sinus reconstruction with mucosa reconstruction, preserving the nasofrontal duct.

Participants We enrolled eight consecutive patients who underwent bifrontal craniotomy associated with frontal sinus mucosa laceration.

Main Outcome Measures A portion of the mucosa was extracted during the reconstructive procedure and was sent for microbiological analysis.

Results None of the patients presented with the bacterial flora in the mucosal cultures. No patient experienced postoperative cerebrospinal fluid leakage or meningitis. One patient with a clinical history of chronic maxillary sinusitis presented with a subcutaneous abscess around the forehead at 9 months postoperatively. The patient rapidly recovered after receiving oral administration of antibiotics.

Conclusions Our findings demonstrated that the frontal sinuses were maintained in an aseptic environment in all cases. The results may encourage the development and wider use of transfrontal sinus approaches.
Hexafluoroisopropanol-Induced Facial Selectivity in a Hindered Diels–Alder Reaction
Authors: Kornfilt David J. P. , Chamberlain Brian T. , Wagner Florence F. , Chataigner Isabelle , Spezia Riccardo
Published: January 2023

BRD4780 is a small molecule that can selectively clear mutant MUC1-fs protein in mucin kidney disease models. Prior syntheses of BRD4780 were unsuitable for preparation on large scale. In this manuscript, HFIP is described as a unique solvent that allowed the key Diels–Alder reaction to proceed with >20:1 endo diastereoselectivity, enabling the kg-scale preparation of BRD4780 for further studies.
Single-Center Experience of Pulmonary Endarterectomy for Chronic Thromboembolic Pulmonary Hypertension: The Results from the Tabriz University Medical Sciences (TUMS) CTEPH Program
Authors: Parvizi Rezayat , Bilehjani Eisa , Mahmoudian Babak , Koohi Ata , Shojaan Hooriah , Ansarin Khalil , Rashidi Farid
Published: January 2023

Introduction Pulmonary endarterectomy (PEA) remains the preferred and potentially curative option for patients with chronic thromboembolic pulmonary hypertension (CTEPH). This study aimed to report the results of PEA for CTEPH in a tertiary center in Tabriz, Iran.

Methods We analyzed the results of 42 CTEPH patients undergoing PEA, who were enrolled in the Tabriz University of Medical Sciences (TUMS-CTEPH) from January 2016 to October 2020. The main outcome measures included the New York Heart Association (NYHA) functional classification, the 6-Minute Walk Distance, hemodynamic measures in right heart catheterization, morbidity, and mortality.

Results There was a significant improvement in the NYHA function class (2.6 ± 0.5 vs 1.1 ± 0.34), mean pulmonary arterial pressure (47.1 ± 13 vs 27.9 ± 8 mm Hg), cardiac output (4.3 ± 1.06 vs 5.9 ± 1.2 L/min), and pulmonary vascular resistance (709.4 ± 297.5 vs 214 ± 77 dyn s/cm5). Fifteen patients (35%) developed complications. The most common complication (10 [23%]) was reperfusion injury. Also, postsurgical mortality was 4% during hospital admission and 1-year follow-up.

Conclusion This is the first single-center report of PEA from Iran. Post-PEA and 1-year survival were acceptable as a referral center. PEA can be performed safe with low mortality. Greater awareness of PEA and patients' access to experienced CTEPH centers are important issues.
Implementation of Eye-Tracking Technology to Monitor Clinician Fatigue in Routine Clinical Care: A Feasibility Study
Authors: Kadhim Bashar , Khairat Saif , Li Fangyong , Gross Isabel T. , Nath Bidisha , Hauser Ronald G. , Melnick Edward R.
Published: January 2023

Background Physician fatigue increases the likelihood of medical errors. Eye-tracking technology offers an unobtrusive and objective way to measure fatigue but has only been implemented in controlled settings.

Objective Our objective was to determine the feasibility of capturing physiological indicators of fatigue using eye-tracking technology in a real-world clinical setting.

Methods A mixed-methods feasibility study was performed in a convenience sample of clinicians practicing in an urban, academic emergency department from November 11 to December 15, 2021. Outcomes included fatigue assessed at the beginning and end of each shift via eye-tracking (with low scores indicating greater fatigue) and self-report.

Results Among 15 participants, self-reported fatigue and task load increased from the beginning to the end of their shift (fatigue visual analog scale [FVAS] 3.7–4.6, p = 0.04; physician task load [PTL] 97.7–154.3, p = 0.01). It was feasible to collect eye-tracking data at a fixed computer workstation with twice daily calibration and 61% capture of reliable data when the clinician was working at the study computer. Eye-tracking metrics did not change significantly from the beginning to the end of the shift. Eye metric fatigue score was associated with the change in PTL score (r 0.59, p = 0.02) but not FVAS. This association persisted after adjusting for age, gender, and role, with every 10-point increase in PTL, there was a 0.02-point increase in fatigue score (p = 0.04).

Conclusion It is unclear whether the inability to detect fatigue via eye-tracking in routine clinical care was due to confounding factors, the technology, study design, sample size, or an absence of physiological fatigue. Further research and advances in functionality are needed to determine the eye-tracking technology's role in measuring clinician fatigue in routine care.
Robotic-Assisted Laparoscopic Complete Mesocolic Excision
Authors: Sahin Inci , Baca Bilgi
Published: January 2023

Complete mesocolic excision (CME) with central vascular ligation is a relatively new technique in the surgical treatment of right-sided colon cancer. Although the technique was originally designed for open surgery, minimally invasive CME has quickly been embraced by colorectal surgeons. Robotic-assisted laparoscopic surgery has some certain advantages over open and standard laparoscopic surgery, and is increasingly utilized in colorectal surgery. In this review, the technical aspects and outcomes of robotic-assisted laparoscopic complete mesocolic excision will be described.
Patients With Significant Medical Comorbidities May Benefit from Unicompartmental Knee Arthroplasty Over Total Knee Arthroplasty
Authors: Pascual-Leone Nicolas , Sloan Matthew , Shah Vivek M. , Sheth Neil P.
Published: January 2023

Many studies have compared outcomes in total knee arthroplasty (TKA) versus unicompartmental knee arthroplasty (UKA); however, to the authors' knowledge, there is no study evaluating complication rates in patients with significant comorbidities. The purpose of this retrospective study was to compare the incidence of postoperative complications, readmission and reoperation rates, length of stay (LOS), and discharge location for patients with significant medical comorbidities undergoing TKA versus UKA. Using the NSQIP database from 2008 to 2018, patients were identified by CPT code (27447 or 27446) and admission diagnostic code of primary osteoarthritis and included in the study if they had an American Society of Anesthesia score greater than or equal to 3. Chi-square test was used to compare categorical variables and t-test for continuous variables. Multivariate regression was used to compare outcomes of interest between groups. A total of 167,054 patients were analyzed with 97.3% undergoing TKA. TKA patients had a greater overall complication rate than those undergoing UKA (p < 0.001). Readmission rates were approximately 1.5 times higher in TKA compared with UKA (p = 0.002), while no statistically significant difference was discovered in reoperation rates (p = 0.868). TKA was also associated with decreased rates of same day discharge, discharge within 24 hours of surgery, and discharge home (p < 0.001, <0.001, and <0.001, respectively). This study found an increase in complication rates, readmission rates, and LOS, along with a lower likelihood of discharge home when undergoing a TKA. These findings suggest that patients with significant medical comorbidities at baseline may benefit from UKA over TKA when anatomically indicated.
Quality of a master’s degree in education in Ecuador
Authors: Ambrós-Pallarés Alba , Puig Marta Sabariego , Moreno Concepción Fuentes
Published: January 2023

This study assesses the quality of a Master’s Degree in education in Ecuador, a program delivered jointly by three institutions (the Ecuadorian Ministry of Education, the National Education University of Ecuador and the University of Barcelona) from 2017 to 2019. The study adopts a multi-dimensional definition of quality that encompasses organization, teaching and trainees’ satisfaction with the value of the course for their professional development. A survey was conducted among 308 trainee teachers using an online questionnaire featuring both open and closed questions. The descriptive analysis of the variables was performed with SPSS and the qualitative information was analyzed using Nvivo12. The findings showed evidence of quality in organization, administration and teaching, in addition to trainee satisfaction with the personal and professional benefits of the course. The study concludes with recommendations for adapting the pedagogical and didactic contents of the master’s degree to the Ecuadorian context and modifying the organization of the face-to-face phase. Evidence is also offered of the value of blended learning and suggestions are made for ongoing institutional self-evaluation to ensure continued improvements and internal regulation in Ecuadorian higher education, and to further develop the government’s Good Living program.
Global existence and wave breaking for a stochastic two-component Camassa–Holm system
Authors: Chen Yajie , Miao Yingting , Shi Shijie
Published: January 2023

In this paper, we study the stochastic two-component Camassa–Holm shallow water system on R and T≔R/2πZ. We first establish the existence, uniqueness, and blow-up criterion of the pathwise strong solution to the initial value problem with nonlinear noise. Then, we consider the impact of noise on preventing blow-up. In both nonlinear and linear noise cases, we establish global existence. In the nonlinear noise case, the global existence holds true with probability 1 if a Lyapunov-type condition is satisfied. In the linear noise case, we provide a lower bound for the probability that the solution exists globally. Furthermore, in the linear noise and the periodic case, we formulate a precise condition on initial data that leads to blow-up of strong solutions with a positive probability, and the lower bound for this probability is also estimated.
Electron spin resonance on a 2D van der Waals CrBr3 uniaxial ferromagnet
Authors: Clemente Gabriele , Moret Massimo , del Águila Andrés Granados , Hussain Muhammad , Sofer Zdeněk , Zhou Jiayuan , Liu Xue , Fanciulli Marco , Moro Fabrizio
Published: January 2023

We report on the electron spin resonance (ESR) properties of a van der Waals bulk CrBr3 single crystal. Angular- and temperature-dependent studies are performed in the range of the critical temperature for ferromagnetic order. The angular-dependent data enable the determination of a strong uniaxial magnetic anisotropy constant, K, with the easy axis of magnetization being parallel to the crystallographic c axis. The peak-to-peak ESR linewidth below the Curie temperature shows contributions from the term (3 cos2 θ−1)2, thus suggesting the occurrence of long-wavelength (q → 0) modes of spin fluctuations typical for 2D systems. Finally, we analyze the temperature dependence of the double integrated ESR intensity, resonance field, and linewidth for the direction of the magnetic field parallel and perpendicular to the c easy axis. We determine Weiss's constant and the thermal dependence of K and observe the crossover region from linewidth narrowing to broadening approaching the critical temperature. Finally, we discuss our findings in the view of the potential application of CrBr3 in perpendicular magnetic tunneling junctions.
Frequency response of cantilevered plates of small aspect ratio immersed in viscous fluids
Authors: Shen Naijian , Chakraborty Debadi , Sader John E.
Published: January 2023

Comprehensive theoretical models for the dynamic response of slender cantilevered beams immersed in fluid have been widely reported, while the distinct behavior of wide cantilevered plates has received comparatively little attention. In this article, we develop an exact analytical theory for the resonant response of rectangular cantilevered plates of zero length-to-width aspect ratio that are immersed in unbounded viscous fluids. Unlike the opposite slender limit of large aspect ratio, the hydrodynamic load experienced by zero-aspect-ratio cantilevered plates is inherently non-local, which can strongly affect the individual mode shapes of the plate. In addition, finite-element-method simulations are reported for two- and three-dimensional cases of zero and finite aspect ratio, respectively. Accuracy of the present theory and that of Atkinson and Manrique de Lara [J. Sound Vib. 300, 352 (2007)] for small viscosity and zero aspect ratio is assessed using the former simulations. The latter simulations are used to clarify the regime of validity of the present theory as a function of aspect ratio, along with that of existing theory for slender (large aspect ratio) beams. The results of this study are expected to be of practical importance to micro- and nano-electromechanical system design and their applications.
Observation of filaments in mega-ampere dense plasma focus within pure deuterium by means of simultaneous schlieren and interferometry diagnostics
Authors: Kubes P. , Paduch M. , Auluck S. , Sadowski M. J. , Cikhardt J. , Klir D. , Kravarik J. , Malir J. , Munzar V. , Novotný J. , Rezac K. , Szymaszek A. , Tomaszewski K.
Published: January 2023

Fifteen-frames interferometric diagnostics at the PF-1000 facility was enhanced by adding four frames of the schlieren diagnostics and by splitting of four channels in the optical delay line. This setup enabled the visualization of gradients in the plasma density perpendicular to the direction of the diagnostic laser beam, and their relationship with larger structures visualized by using laser interferometry. The schlieren pictures showed filamentary structures of submillimeter 200–300 μm diameter in shots performed with pure deuterium filling. Filaments were observed in a thin (millimeter-thick) lateral-boundary layer, in lobules, and in internal fast transforming regions of the dense plasma column. Their high-density gradients and location in the regions of recorded (or inferred) currents indicated local concentrations of the magnetic field and current distribution. Millimeter- and submillimeter-size sources of fast charged particles, which were identified in the recorded ion pinhole pictures, have been conjectured to be a manifestation of high local concentrations of the magnetic energy.
Moiré-induced bandgap tuning by varying electric dipole in InSe/CuSe vertical heterostructure
Authors: Li Bo , Bagheri Tagani Meysam , Izadi Vishkayi Sahar , Yang Yumu , Wang Jing , Tian Qiwei , Zhang Chen , Zhang Li , Yin Long-Jing , Tian Yuan , Zhang Lijie , Qin Zhihui
Published: January 2023

The stacked two layered materials with a lattice constant mismatch and/or with a twist angle relative to each other can create a moiré pattern, modulating electronic properties of pristine materials. Here, we combine scanning tunneling microscopy/spectroscopy and density functional theory calculations to investigate the moiré potential induced bandgap tuning in an InSe/CuSe vertical heterostructure synthesized by a two-step of molecular beam epitaxy. Scanning tunneling microscopy measurements demonstrate the heterostructure with a superlattice periodicity of ∼3.48 nm and a twist angle of about 11° between the monolayers. Scanning tunneling spectroscopy record on the different stacking sites of the heterostructure reveals the bandgap of the InSe is location-dependent and a variation of 400 meV is observed. Density functional theory calculations reveal that the moiré-induce electric dipole in the monolayer InSe is the key factor for tuning the bandgap. Moreover, charge transfer between CuSe and InSe also contributes to the bandgap variation due to its stacking. We also show that the moiré potential not only can tune the bandgap of InSe but also can vanish the Dirac nodal line of CuSe in some stackings. Our explorations provide valuable information in understanding electronic properties of two-dimensional moiré materials.
Polyimide dynamically compressed to decomposition pressures: Two-wave structures captured by velocimetry and modeling
Authors: Huber R. C. , Dattelbaum D. M. , Lang J. M. , Coe Joshua D. , Peterson J. H. , Bartram B. , Gibson L. L.
Published: January 2023

We performed a series of six plate impact experiments on polyimide and modeled them using new reactant and products equations of state combined with an Arrhenius rate model. The first experiment was diagnosed with embedded electromagnetic velocity gauges through which we directly observed attenuation of the lead shock to an approximately constant state over a propagation distance of roughly 4 mm. Simulated gauge profiles were in excellent qualitative agreement with experiment and suggested a sluggish chemical reaction that did not proceed to completion. The remaining five experiments were conducted in a transmission geometry and diagnosed velocimetrically at the sample/window interface. All five of these yielded profiles with a sharp shock followed by a more gradual approach to maximum interface velocity that was “rounded” to varying degree. These profiles proved difficult to interpret unambiguously due to the convolution of the reactive wave upon first shock with reflection of the lead wave and reshock or release by the window. Comparison with thermochemical calculations strongly suggests that the point of maximum interface velocity corresponds to the equilibrium reshock or release locus. We discuss the implications of this point for the practice of impedance matching based on the reflected Hugoniot of reactive materials such as polymers. The reactant and thermochemical products equations of state are developmental SESAME tables 97710 and 97720, respectively.
An active straight waveguide polarization rotator in single crystal thin film barium titanate-on-insulator
Authors: Cao Yu , Ng Jun Da , Lin Hong-Lin , Tan Siew Li , Danner Aaron
Published: January 2023

Electro-optic materials play an essential role in telecommunications. In active devices like Mach–Zehnder modulators, typically the diagonal Pockels coefficients are employed to induce an optical phase shift through electrical tuning of the refractive index along an optic axis. On the other hand, waveguide polarization rotators are usually passive devices where asymmetric structures or specially designed couplers are used. In this Letter, we exploit off diagonal Pockels coefficients to demonstrate an active straight waveguide polarization rotator using a c-axis single crystal thin film barium titanate (BTO)-on-insulator, with a maximum power conversion of ∼30% from the input TE (or TM) mode into its orthogonal mode observed. The device is switched on or off through an applied voltage and is demonstrated in a simple straight waveguide. A TM output extinction ratio of 26.1 dB is achieved in the device with a TE input. The r51 value in the BTO thin film is estimated to be around 600 pm/V. This work adds a different polarization rotation scheme to the active photonics family.
Influence of wavelength and accumulated fluence at picosecond laser-induced surface roughening of copper on secondary electron yield
Authors: Bez Elena , Himmerlich Marcel , Lorenz Pierre , Ehrhardt Martin , Gunn Aidan Graham , Pfeiffer Stephan , Rimoldi Martino , Taborelli Mauro , Zimmer Klaus , Chiggiato Paolo , Anders André
Published: January 2023

Ultrashort-pulse laser processing of copper is performed in air to reduce the secondary electron yield (SEY). By UV (355 nm), green (532 nm), and IR (1064 nm) laser-light induced surface modification, this study investigates the influence of the most relevant experimental parameters, such as laser power, scanning speed, and scanning line distance (represented as accumulated fluence) on the ablation depth, surface oxidation, topography, and ultimately on the SEY. Increasing the accumulated laser fluence results in a gradual change from a Cu2O to a CuO-dominated surface with deeper micrometer trenches, higher density of redeposited surface particles from the plasma phase, and a reduced SEY. While the surface modifications are less pronounced for IR radiation at low accumulated fluence (<1000 J/cm2), analogous results are obtained for all wavelengths when reaching the nonlinear absorption regime, for which the SEY maximum converges to 0.7. Furthermore, independent of the extent of the structural transformations, an electron-induced surface conditioning at 250 eV allows a reduction of the SEY maximum below unity at doses of 5×10-4 C/mm2. Consequently, optimization of processing parameters for application in particle accelerators can be obtained for a sufficiently low SEY at controlled ablation depth and surface particle density, which are factors that limit the surface impedance and the applicability of the material processing for ultrahigh vacuum systems. The relations between processing parameters and surface features will provide guidance in treating the surface of vacuum components, especially beam screens of selected magnets of the Large Hadron Collider or of future colliders.
Free energy barriers for anti-freeze protein engulfment in ice: Effects of supercooling, footprint size, and spatial separation
Authors: Farag Hossam , Peters Baron
Published: January 2023

Anti-freeze proteins (AFPs) protect organisms at freezing conditions by attaching to the ice surface and arresting its growth. Each adsorbed AFP locally pins the ice surface, resulting in a metastable dimple for which the interfacial forces counteract the driving force for growth. As supercooling increases, these metastable dimples become deeper, until metastability is lost in an engulfment event where the ice irreversibly swallows the AFP. Engulfment resembles nucleation in some respects, and this paper develops a model for the “critical profile” and free energy barrier for the engulfment process. Specifically, we variationally optimize the ice–water interface and estimate the free energy barrier as a function of the supercooling, the AFP footprint size, and the distance to neighboring AFPs on the ice surface. Finally, we use symbolic regression to derive a simple closed-form expression for the free energy barrier as a function of two physically interpretable, dimensionless parameters.
Coupling between a turbulent outer flow and an adjacent porous medium: High resolved Particle Image Velocimetry measurements
Authors: Härter J. , Martínez D. S. , Poser R. , Weigand B. , Lamanna G.
Published: January 2023

The existence of large-scale turbulent structures within a porous medium, generated through the interaction with a turbulent outer flow, is a highly debated topic, albeit most of the analysis is based on computational studies. This study contributes to the ongoing discussion by providing detailed point-measurements of the velocity in both regions by means of Particle Image Velocimetry (PIV). Two porous models of different porosity are investigated at three Reynolds numbers. The design of the experiments is based on theoretical studies to guarantee the presence of an unperturbed viscous layer at the interface (alias permeability Reynolds numbers of order one). Under these conditions and in compliance with theoretical predictions, the PIV data show the rapid dumping of turbulent fluctuations within the first pore cavities and can be used to validate closure models for volume-averaged computational studies. A point-data analysis is applied in the interfacial region by requiring continuity of tangential velocity and shear stress. The presence of the attached viscous layer implies that the coupling condition for momentum transfer must be controlled by shear, leading to the well-known Beavers and Joseph coupling condition. PIV data corroborate this statement and show the close interdependency between the penetration depth of the outer flow in the porous media and the characteristics of the vortical secondary flows induced by the strain rate at the pore scale. Consequently, the Beavers and Joseph-slip coefficient depends only upon the topology of the porous medium, at least as long as no transition to a perturbed mixing layer occurs at the interface.
Plasma elongation effect on the parity change in global electromagnetic ion temperature gradient modes and intrinsic rotation generation
Authors: Kaang Helen H. , Kim S. S. , Kang J. , Jhang Hogun , Kim Juhyung , Ko S. H.
Published: January 2023

A study is made of the effect of plasma elongation (κ) on parity of a global electromagnetic (EM) ion temperature gradient mode and intrinsic rotation generation. An odd parity component of the mode is generated by global EM effects and increases with β (=plasma thermal energy/magnetic energy), enhancing the symmetry breaking and subsequent Reynolds stress [Kaang et al., Phys. Plasmas 25, 012505 (2018)]. The plasma elongation is shown to diminish the parity change via the reduction in the effective ion temperature gradient by a factor α=1−E′, where E=r(κ−1)/(κ+1). A quasi-linear analysis indicates that plasma elongation can weaken the generation of intrinsic torque induced by the global EM effect as a result of the decline of the parity change.
Sparsity of the electron repulsion integral tensor using different localized virtual orbital representations in local second-order Møller–Plesset theory
Authors: Wang Zhenling , Aldossary Abdulrahman , Head-Gordon Martin
Published: January 2023

Utilizing localized orbitals, local correlation theory can reduce the unphysically high system-size scaling of post-Hartree–Fock (post-HF) methods to linear scaling in insulating molecules. The sparsity of the four-index electron repulsion integral (ERI) tensor is central to achieving this reduction. For second-order Møller–Plesset theory (MP2), one of the simplest post-HF methods, only the (ia|jb) ERIs are needed, coupling occupied orbitals i, j and virtuals a, b. In this paper, we compare the numerical sparsity (called the “ragged list”) and two other approaches revealing the low-rank sparsity of the ERI. The ragged list requires only one set of (localized) virtual orbitals, and we find that the orthogonal valence virtual-hard virtual set of virtuals originally proposed by Subotnik et al. gives the sparsest ERI tensor. To further compress the ERI tensor, the pair natural orbital (PNO) type representation uses different sets of virtual orbitals for different occupied orbital pairs, while the occupied-specific virtual (OSV) approach uses different virtuals for each occupied orbital. Our results indicate that while the low-rank PNO representation achieves significant rank reduction, it also requires more memory than the ragged list. The OSV approach requires similar memory to that of the ragged list, but it involves greater algorithmic complexity. An approximation (called the “fixed sparsity pattern”) for solving the local MP2 equations using the numerically sparse ERI tensor is proposed and tested to be sufficiently accurate and to have highly controllable error. A low-scaling local MP2 algorithm based on the ragged list and the fixed sparsity pattern is therefore promising.
Fine-structure of electromagnetic radiation reflected from the O–X mode conversion zone in magnetized plasma
Authors: Shalashov A. G. , Gospodchikov E. D.
Published: January 2023

The linear coupling between the ordinary and extraordinary waves in the vicinity of the plasma cutoff is used for the heating of overdense plasma in toroidal magnetic devices. If the mode coupling is not perfect, there is reflected ordinary wave radiation. In this paper, we analyze the structure of this radiation in a realistic case of an incident beam with a finite aperture. It is shown that reflection from the evanescent layer in inhomogeneous gyrotropic plasma results in wave distributions with a non-zero-angular momentum. A helicity of the reflected beam results in unusual effects, at least in the plasma electrodynamics, which are identified and discussed.
Experimental investigations of gas–liquid two-phase flow in a horizontal mini pipe: Flow regime, void friction, and frictional pressure drops
Authors: Zhang Jingzhi , Lei Li , Cheng Cheng , Huang Chonghai , Xiao Qi , Xin Gongming , Wang Man
Published: January 2023

Experimental studies of air–water two-phase flows in a mini tube with an inner diameter of 3.12 mm have been conducted in terms of the flow pattern, void fraction, and pressure gradients. The fluid velocities range from 0.065 to 21.78 m/s and from 0.109 to 1.835 m/s, respectively. A right-angle prism is applied to capture images simultaneously from two perpendicular directions. Three-dimensional gas–liquid interfaces are reconstructed with the obtained images from two directions. The gas void fraction is investigated using this method, which is experimentally validated with the quick closing valves method. Three flow patterns are obtained in the present work, which is bubbly, slug, and annular flows. The Probability Density Functions of the cross-sectional void fraction show that the intermittent flow has two peaks and the annular flow has only one peak. Volumetric void fraction is affected by the flow pattern and the flow rate. However, at very high gas velocities, volumetric void fraction is independent of the liquid rate. A new frictional pressure drop correlation is proposed based on the experimental data.
Characterization and predictive modeling of a trajectory-oriented dual-mode scramjet combustor
Authors: Zhou Ruixu , Li Tuo , Li Xinyang , Lian Huan
Published: January 2023

Linear and nonlinear characteristics of a dual-mode scramjet combustor are investigated in ground-simulated acceleration and deceleration trajectory experiments. The experiments were conducted in the direct-connected transient flight trajectory simulator 1 at the Institute of Mechanics, Chinese Academy of Sciences. High-frequency pressure measurements, the schlieren, and CH* chemiluminescence high-speed imaging were applied for the diagnostics. Based on the quantitative analysis, the physical processes of acceleration and deceleration in general represent similar nonlinear characteristics. The linear characteristics are limited to the low-frequency oscillation period in the presence of physical governing mechanisms. A nonlinear predictive model of the dual-mode scramjet combustor based on historical measurements is proposed due to its generality for the acceleration and deceleration trajectory.
Comparative heat transfer analysis on Fe3O4–H2O and Fe3O4–Cu–H2O flow inside a tilted square porous cavity with shape effects
Authors: Thirumalaisamy K. , Ramachandran Sivaraj
Published: January 2023

The objective of this paper is to investigate the energy transmission rate's features of the natural convective radiative Fe3O4–H2O nanofluid and Fe3O4–Cu–H2O hybrid nanofluid flow in a tilted square porous cavity under the influence of heat source/sink. The marker and cell method is adopted to solve the system of partial differential equations. The outcomes explore that in the existence of heat source, by augmenting the volume fraction of spherical-, cylindrical-, column-, and lamina-shaped nanoparticles from 1% to 5% in water, the average heat transfer rate is boosted by 6.07%, 8.36%, 9.89%, and 14.95%, respectively. In the existence of heat sink, the increment is noticed as 2.67%, 3.68%, 4.37%, and 6.64%, respectively. Therefore, the shape of the nanoparticles considerably varies the heat transfer rate. In the existence of heat source, by magnifying the volume fraction of spherical-, cylindrical-, column-, and lamina-shaped Fe3O4–Cu nanoparticles from 1% to 5% in water, the mean heat transfer rate is magnified by 7.23%, 11.03%, 14.15%, and 31.36%, respectively. In the existence of heat sink, the magnification is detected as 3.18%, 4.87%, 6.27%, and 14.09%, respectively. This result confirms that the proper combination of nanoparticles considerably enhances the heat transfer characteristics of base fluids. The findings of this study may be helpful for a better understanding of hydrothermal features of thermal systems such as heat exchangers, helical heat sinks, solar collectors, periodic pin-fins, mini shell and tube heat exchangers, plate evaporators, photothermal cancer treatment, and microvascular vessels using various unitary and hybrid nanofluids.
Characteristics of cavitation evolution through a butterfly valve under transient regulation
Authors: Zhang Guang , Wang Wei Wei , Zhang Hao Tian , Kim Heuy-Dong , Lin Zhe
Published: January 2023

As the key control equipment for the transmission of the fluid medium, butterfly valves are widely used in transmission systems of media in the energy, chemical industry, metallurgy, aerospace engineering, and other fields, playing an important role in the stability and reliability of system operation. When the flow cross section suddenly changes, the pressure rapidly decreases the downstream, leading to cavitation in butterfly valves. Cavitation causes serious erosion and damage in the valve core and pipeline surface, resulting in leakage and noise problems in butterfly valves, which seriously affects the regulation performance and lifetime of butterfly valves. In this study, numerical analyses are conducted to investigate cavitation evolution at the transient regulation of a butterfly plate through a butterfly valve model. Moreover, the effects of the valve opening degree and rotating speed on the cavitation volume and distribution, rate of cavitation volume change, growth–collapse rate of cavitation, and correlation between cavitation and vortex in the opening and closing processes of butterfly valves are investigated. Due to the influence of transient regulation and flow hysteresis, the characteristic parameters and evolution of cavitation exhibit different behaviors in the opening and closing processes of butterfly valves.
Electronic transport in copper–graphene composites
Authors: Subedi Kashi N. , Nepal Kishor , Ugwumadu Chinonso , Kappagantula Keerti , Drabold D. A.
Published: January 2023

We investigate electronic transport properties of copper–graphene (Cu–G) composites using a density-functional theory (DFT) framework. Conduction in composites is studied by varying the interfacial distance of copper/graphene/copper (Cu/G/Cu) interface models. Electronic conductivity of the models computed using the Kubo–Greenwood formula shows that the conductivity increases with decreasing Cu–G distance and saturates below a threshold Cu–G distance. The DFT-based Bader charge analysis indicates increasing charge transfer between Cu atoms at the interfacial layers and the graphene with decreasing Cu–G distance. The electronic density of states reveals increasing contributions from both copper and carbon atoms near the Fermi level with decreasing Cu–G interfacial distance. By computing the space-projected conductivity of the Cu/G/Cu models, we show that the graphene forms a bridge to the electronic conduction at small Cu–G distances, thereby enhancing the conductivity.
Numerical simulation on the shock wave focusing detonation process in the semicircle reflector
Authors: Du Peng , Xue Rui , Yang Zhao , Liu Bing , Zhu Shaohua
Published: January 2023

Shock wave focusing is considered a new type of initiation method that does not require external ignition devices. For this method, understanding the shock wave/flame interaction accurately is one of the critical issues for revealing the ignition and triggering mechanisms during shock wave focusing processes. In this study, numerical simulations were carried out to investigate the detailed flow field evolution of the focusing process with kerosene as fuel. Two detonation initiation modes were found during the shock wave focusing processes, which were the direct initiation mode and the reflected shock wave collision initiation mode, respectively. At the detonation wave propagation stage, the primary detonation wave decouples and fails to propagate out of the cavity. The multiple initiation phenomenon occurs in the cavity, and it dominated detonation waves to propagate outside of the cavity to accomplish one thermal cycle. There is no positive correlation between jet temperature and detonation wave propagation velocity. When the jet temperature is low, the detonation wave velocity dominated by the multiple initiation mode is the fastest. The analysis of the shock wave focusing process under different jet velocities showed that when the jet velocity was lower than 2 Ma, the decoupling of the primary detonation wave failed to induce multiple detonation waves. Driven by the vortex in the semicircular cavity, the flame is almost stationary, which means the failure of the detonation wave propagation process.
Structural, electronic, and magnetic properties of CoFeVGe-based compounds: Experiment and theory
Authors: Kharel Parashu , Lehmann Zachary , Baker Gavin , Stuelke Lukas , Valloppilly Shah , Shand Paul M. , Lukashev Pavel V.
Published: January 2023

We have carried out a combined theoretical and experimental investigation of both stoichiometric and nonstoichiometric CoFeVGe alloys. In particular, we have investigated CoFeVGe, Co1.25Fe0.75VGe, Co0.75Fe1.25VGe, and CoFe0.75VGe bulk alloys. Our first principles calculations suggest that all four alloys show ferromagnetic order, where CoFeVGe, Co1.25Fe0.75VGe, and Co0.75Fe1.25VGe are highly spin polarized with spin polarization values of over 80%. However, the spin polarization value of CoFe0.75VGe is only about 60%. We have synthesized all four samples using arc melting and high-vacuum annealing at 600 °C for 48 hours. The room temperature x-ray diffraction of these samples exhibits a cubic crystal structure with disorder. All the samples show single magnetic transitions at their Curie temperatures, where the Curie temperature and high field (3T) magnetization are 288 K and 42 emu/g; 305 K and 1.5 emu/g; 238 K and 39 emu/g; and 306 K and 35 emu/g for CoFeVGe, Co1.25Fe0.75VGe, Co0.75Fe1.25VGe, and CoFe0.75VGe, respectively.
Adapting the ‘First 2000 Days maternal and child healthcare framework’ in the aftermath of the COVID-19 pandemic: ensuring equity in the new world
Authors: Mendoza Diaz Antonio , Brooker Ron , Cibralic Sara , Murphy Elisabeth , Woolfenden Sue , Eapen Valsamma
Published: January 2023

The purpose of this perspective article is to emphasise the importance of the ‘First 2000 Days’ policy of life from conception to age five, and to propose new directions in which the policy’s implementation could be extended for the benefit of children and families. The proposed approach highlights principles of responsiveness, integration, sustainability and equity, specifying initiatives that embody the kind of innovation each principle aspires to. The article also proposes innovations in data collection and linkages that would strengthen the implementation of first 2000 days policies and frameworks. This perspective proposes a framework that could improve health systems implementation of services in the first 5 years of life, by proposing a well-coordinated continuum of services with integrated physical and digital solutions. This has the potential to transform how the health system monitors and responds to children and families’ needs in the critical early years of life during and beyond the current pandemic.