bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustic scattering effect prediction of helicopter fuselage based on BEM and convective FW–H equation
Authors: Wang Zeyang , Huang Jun , Yi Mingxu
Published: June 2022

The main acoustic noise source of helicopters is supposed to be the rotor blades, but the scattering effect of the helicopter fuselage sometimes cannot be ignored. For the accuracy of acoustic noise prediction and the research on the scattering affections of the helicopter fuselage, an FWH–BEM Method (FBM) based on convective FW–H equation and boundary element method (BEM) is presented for the prediction of the noise scattering effects of helicopter fuselage and the approach to the calculation of a helicopter’s acoustic noise field. In this paper, different fuselage models are adopted for the comparisons of the acoustic noise scattered by different types of fuselages. According to the discovery that helicopter fuselages with sharp edges can bring more significant acoustic scattering effects, a research on the influence of radius of curvature (RC), which reflects the sharpness of fuselage sharp edges, is also carried out. In addition, the acoustic scattering effects of the same type of fuselage but with different length, width and height ratios are also compared for discovering the influences of the fuselage size. The presented FBM is efficient to analyze the acoustic scattering effects of the helicopter fuselage and predict the acoustic noise field, taking both the rotor and the fuselage into account. Besides, the research in this paper leads to the discovery of the influence factors of the acoustic scattering effects and helps the proper selection of the fuselage in a helicopter stealth design.
Free electron harmonic generation in heavily doped semiconductors: the role of the materials properties
Authors: De Luca Federico , Ortolani Michele , Ciracì Cristian
Published: June 2022

Heavily doped semiconductors have emerged as low-loss and tunable materials for plasmonics at mid-infrared frequencies. We analyze the nonlinear optical response of free electrons and show how nonlinear optical phenomena associated with high electron concentration are influenced by the intrinsic properties of semiconductors, namely background permittivity and effective mass. We apply our recently developed hydrodynamic description that takes into account nonlinear contributions up to the third order, usually negligible for noble metals, to compare third-harmonic generation from InP, Ge, GaAs, Si, ITO and InSb. We show how free electron nonlinearities may be enhanced with a proper choice of the semiconductor.
Modeling of the Construction for the Combustion Chamber of the Gas Calorimeter in the Aspect of Exhaust Gas Homogenization in the Measuring Space
Authors: Markowski Jarosław , Olejniczak Damian , Nowacki Marcin , Mądry Jacek , Netter Krzysztof , Imilkowski Paweł
Published: June 2022

The assessment of the physicochemical parameters of fuels is particularly important in energy generation processes implemented using combustion processes. The calorific value of the fuels used is important in these processes. The calorific value of fuel is the basic parameter from which the mass of fuel necessary to generate a certain amount of energy results. Calorimeters are used to determine the calorific value of fuels. The subject of analyzes is the conceptual design of the calorimeter for gaseous fuel testing. A special element in the construction of the calorimeter is the combustion chamber. In its initial part, the gaseous fuel oxidation process is carried out, and in the final part, the required parameters are measured. In order to obtain high accuracy in the measurement of selected thermodynamic parameters, it is necessary to ensure homogeneity of the exhaust gases flowing in the measurement space. For this purpose, the construction of the combustion chamber was developed and simulation tests aimed at homogenization of exhaust gases in the chamber measuring space were carried out. An example of the construction and the tests carried out are provided in this article.
Numerical and Experimental NVH Testing of Vehicle Components – from Simple Part to Complex Assembly
Authors: Pietrusiak Damian , Wróbel Jakub , Czechowski Mateusz , Fiebig Wiesław
Published: June 2022

Increased demanding in the fields of noise pollution, human comfort and health finds its prints in the development of automotive components. The paper presents general problems of noise and vibration in the vehicles. Main sources and transfer paths are identified. The sound quality – psychoacoustic aspects are also described. In the second part of the article, authors presents an example of numerical and experimental approach to the undercarriage components testing in the field of noise and vibrations problems. Presented examples leads through the basic investigations of particular component to the investigations of complex subassemblies.
Numerical Modeling of the Mechanical Characteristics of the Magnetorheological Elastomers
Authors: Kukla Mateusz , Talaśka Krzysztof , Biszczanik Aleksandra , Górecki Jan
Published: June 2022

The paper presents the work results associated with the implementation of the developed mathematical model describing the magnetorheological elastomers mechanical characteristics under compressive stress. The employed mathematical instrument constitutes the classic viscoelastic model development, accounting in its structure for the effect of the strain amplitude together with the magnetic field induction on the measured stress values progressive characteristic. The necessity to introduce such changes was demonstrated as a result of earlier studies. Within the this work scope, the structure of the developed numerical model is presented. Further provided are the results of carried out simulations, which are finally juxtaposed and compared with the earlier experiments results. This gives ground to evaluating the proposed model accuracy.
An analysis of trauma-related CT utilization and abnormal findings in emergency department: a one-year retrospective study
Authors: Shubayr N. , Alomairy N.
Published: June 2022

Trauma is one of the major indications for admission to the emergency department (ED) and Computed Tomography (CT) scan requests. Understanding of CT utilization is important to reduce unnecessary imaging and radiation exposure. This study aimed to examine the utilization pattern of CT scans for trauma patients in the ED and how often traumatic abnormalities occurred. A retrospective study was conducted over a one-year period. Data for patients who were admitted to the ED and underwent CT scans for trauma indications, type of CT procedure performed, findings, and prior radiography were collected from the picture archiving and communication system. A total of 881 trauma patients underwent a CT scan as part of their investigation. Abnormalities were identified in 527 (59.9%) of cases and proportional with prior radiography [828 (94%)]. Different types of CT procedures were performed, as requested by the ED physicians, including 450 CT scans of the head, 188 for the spine, 93 for the chest, 45 CT CAP, 29 for the whole-body, 22 for the pelvis, 16 for the chest and abdomen, 13 for the extremities, and 11 for the abdomen. CT of the head was the most common procedure performed for trauma patients with 55% positive findings and may represent an opportunity for reduction of the use of CT scans, taking into consideration validated clinical decision rules. For multiple-trauma patients, a clearly defined criterion must be established to determine which CT procedure is required for these patients based on clinical indications and presentations. Therefore, for better radiation protection practices, a review and improvement of CT protocols, as well as justification and optimization, should be considered for utilization of CT scans for trauma patients.
Diagnose und Therapie der Lyme-Borreliose – alles unklar, alles schlecht?
Authors: Fingerle Volker , Sing Andreas
Published: June 2022

Die durch wenigstens fünf Borrelia (B.) burgdorferi-Arten verursachte Lyme-Borreliose ist die häufigste durch Zecken übertragene Erkrankung in Europa und den USA. Die nur bei entsprechenden Symptomen indizierte mikrobiologische Diagnostik basiert auf dem Nachweis spezifischer Antikörper aus Serum und ggf. Liquor. Nur bei unklaren Fällen sollen PCR und Anzucht aus Hautbiopsie, Liquor oder Gelenkpunktat eingesetzt werden. Für die orale Therapie stehen Amoxicillin, Doxycyclin, Cefuroxim und Azithromycin zur Verfügung, für die i. v. Therapie Cefotaxim, Ceftriaxon und Penicillin G. Eingesetztes Antibiotikum und Dauer der Therapie – 10–30 Tage – orientieren sich an der Manifestation, Schwere der Erkrankung und individueller Verträglichkeit. Die Prognose der therapierten Lyme-Borreliose ist insgesamt als gut einzuschätzen, Defektheilungen sind selbst nach länger bestehenden Erkrankungen im Kindesalter selten.
Simultaneous Modulated Accelerated Radiotherapy (SMART) with Dysphagia Aspiration-Related Structures (DARS) Sparing: Do We Have a Role for Dose Condensation in Locally Advanced Head and Neck Cancer
Authors: Valuvil Nithin Bhaskar , Vishwanath Lokesh
Published: June 2022

Introduction Concurrent chemotherapy integrated with intensity-modulated radiotherapy (IMRT) is the standard of care for locally advanced head and neck cancer. Simultaneous integrated boost technique has allowed differential doses to primary and normal structures permitting significant toxicity reduction. The current study explores the feasibility of the simultaneous modulated accelerated radiotherapy (SMART) technique to enhance cytoreduction and explore the possibility of dose intensification with radiobiologically targeted treatment condensation.

Methods Thirty patients were randomized in an open-labeled study to receive concurrent chemoradiation of 60 Gy in 25 fractions with “SMART” technique or 70 Gy in 35 fractions using conventional intensity-modulated radiotherapy simultaneous integrated boost “IMRT SIB.” The primary endpoints included comparative volumetric cytoreduction between the study and control arm assessed during the course of treatment and final response evaluation. Secondary endpoints involved the assessment of acute toxicity parameters for xerostomia, mucositis, dysphagia, and fatigue.

Results The “SMART” study arm showed comparable volumetric cytoreduction to the conventional “IMRT SIB” arm at midtreatment (p-value = 0.225) as well as toward completion (p-value = 0.476). The study arm did observe 94.4% cytoreduction of tumor volume compared with 88.05% in the conventional arm at the time of response evaluation. In spite of treatment condensation, there was no significant increase in toxicity with “SMART.” There was no difference in the frequency or duration of grade 3 mucositis in the “SMART” arm in spite of intensification (p-value = 0.728). In the “SMART” arm, there was a favorable reduction in the duration of grade ⅔ dysphagia; 2.8 weeks versus 4.6 weeks (p-value = 0.002). Even though the xerostomia was comparable in frequency and intensity, the total duration of xerostomia was 50% less (p-value = 0.001).

Conclusions The “SMART” technique provides a radiobiologically sound, effective, and safe protocol that has the potential to improve the treatment of locally advanced head and neck cancer. The good tolerability and toxicity profile in the study arm is encouraging and facilitates further research.
Disseminated Staphylococcal Disease Complicated with Intracranial Internal Carotid Artery Mycotic Pseudoaneurysm and Cerebral Infarcts—A Rare Presentation in a Malnourished Child
Authors: Das Suman , Ray Biman Kanti , Chakraborty Uddalak , Kabiraj Sujoy
Published: June 2022

A 2.5-year-old girl child patient with moderate malnutrition presented with right forehead abscess followed by ipsilateral orbital cellulitis. She also developed a left hydropneumothorax within a week. Subsequently she had left focal onset seizures with secondary generalized status epilepticus followed by development of left hemiparesis. Neuroimaging showed infarcts of varying ages in the right cerebral hemisphere and basal ganglia. Angiography revealed right internal carotid artery pseudoaneurysm. Blood and pus cultures grew methicillin-resistant Staphylococcus aureus (MRSA). Investigations for immunodeficiency were negative. The patient received vancomycin intravenously for 6 weeks and intercostal tube drainage for hydropneumothorax. She was discharged with an antiepileptic drug and aspirin. There was complete resolution of the orbital cellulitis and hydropneumothorax and also the pseudoaneurysm on follow-up angiography 3 months later.
“Co-construction” in deliberative democracy: lessons from the French Citizens’ Convention for Climate
Authors: Giraudet Louis-Gaëtan , Apouey Bénédicte , Arab Hazem , Baeckelandt Simon , Bégout Philippe , Berghmans Nicolas , Blanc Nathalie , Boulin Jean-Yves , Buge Eric , Courant Dimitri , Dahan Amy , Fabre Adrien , Fourniau Jean-Michel , Gaborit Maxime , Granchamp Laurence , Guillemot Hélène , Jeanpierre Laurent , Landemore Hélène , Laslier Jean-François , Macé Antonin , Mellier Claire , Mounier Sylvain , Pénigaud Théophile , Póvoas Ana , Rafidinarivo Christiane , Reber Bernard , Rozencwajg Romane , Stamenkovic Philippe , Tilikete Selma , Tournus Solène
Published: June 2022

Launched in 2019, the French Citizens’ Convention for Climate (CCC) tasked 150 randomly chosen citizens with proposing fair and effective measures to fight climate change. This was to be fulfilled through an “innovative co-construction procedure”, involving some unspecified external input alongside that from the citizens. Did inputs from the steering bodies undermine the citizens’ accountability for the output? Did co-construction help the output resonate with the general public, as is expected from a citizens’ assembly? To answer these questions, we build on our unique experience in observing the CCC proceedings and documenting them with qualitative and quantitative data. We find that the steering bodies’ input, albeit significant, did not impair the citizens’ agency, creativity, and freedom of choice. While succeeding in creating consensus among the citizens who were involved, this co-constructive approach, however, failed to generate significant support among the broader public. These results call for a strengthening of the commitment structure that determines how follow-up on the proposals from a citizens’ assembly should be conducted.
Inter-particle adhesion induced strong mechanical memory in a dense granular suspension
Authors: Chattopadhyay Sebanti , Majumdar Sayantan
Published: June 2022

Repeated/cyclic shearing can drive amorphous solids to a steady state encoding a memory of the applied strain amplitude. However, recent experiments find that the effect of such memory formation on the mechanical properties of the bulk material is rather weak. Here, we study the memory effect in a yield stress solid formed by a dense suspension of cornstarch particles in paraffin oil. Under cyclic shear, the system evolves toward a steady state showing training-induced strain stiffening and plasticity. A readout reveals that the system encodes a strong memory of the training amplitude (γT) as indicated by a large change in the differential shear modulus. We observe that memory can be encoded for a wide range of γT values both above and below the yielding albeit the strength of the memory decreases with increasing γT. In situ boundary imaging shows strain localization close to the shearing boundaries, while the bulk of the sample moves like a solid plug. In the steady state, the average particle velocity v inside the solid-like region slows down with respect to the moving plate as γ approaches γT; however, as the readout strain crosses γT, v suddenly increases. We demonstrate that inter-particle adhesive interaction is crucial for such a strong memory effect. Interestingly, our system can also remember more than one input only if the training strain with smaller amplitude is applied last.
Phase transition by nanoindentation in a relaxor ferroelectric single crystal PMN-0.3PT: A phase-field investigation
Authors: Qi Changjun , Jiang Yixuan , Wang Xingzhe , Lynch Christopher S.
Published: June 2022

Nanoindentaiton testing has revealed pop-in events in load–displacement curves of relaxor single crystal PMN-0.3PT ferroelectric materials that occur when the indentation depth is small (e.g., dozens of nanometers). Although there has been speculation of an occurrence of phase transition, there is a relative lack of investigation on the domain evolution associated with the phase transition when the pop-in events appear. In the present study, nanoindentation of this material was systematically modeled using phase-field simulations, which capture the domain and phase evolution of a PMN-0.3PT ferroelectric single crystal. The results, qualitatively similar to the experimental results, revealed details of the contribution of phase transformations to pop-in events. The influence of indenter shape, size, and external electric field on the pop-in event was also examined. This work provides a computational evaluation of the effects of the phase transition mechanism in ferroelectric materials under nanoindentation and gives insight into local mechanical loading effects on these electromechanically coupled crystals.
Machine-learning effective many-body potentials for anisotropic particles using orientation-dependent symmetry functions
Authors: Campos-Villalobos Gerardo , Giunta Giuliana , Marín-Aguilar Susana , Dijkstra Marjolein
Published: June 2022

Spherically symmetric atom-centered descriptors of atomic environments have been widely used for constructing potential or free energy surfaces of atomistic and colloidal systems and to characterize local structures using machine learning techniques. However, when particle shapes are non-spherical, as in the case of rods and ellipsoids, standard spherically symmetric structure functions alone produce imprecise descriptions of local environments. In order to account for the effects of orientation, we introduce two- and three-body orientation-dependent particle-centered descriptors for systems composed of rod-like particles. To demonstrate the suitability of the proposed functions, we use an efficient feature selection scheme and simple linear regression to construct coarse-grained many-body interaction potentials for computationally efficient simulations of model systems consisting of colloidal particles with an anisotropic shape: mixtures of colloidal rods and non-adsorbing polymer coils, hard rods enclosed by an elastic microgel shell, and ligand-stabilized nanorods. We validate the machine-learning (ML) effective many-body potentials based on orientation-dependent symmetry functions by using them in direct coexistence simulations to map out the phase behavior of colloidal rods and non-adsorbing polymer coils. We find good agreement with the results obtained from simulations of the true binary mixture, demonstrating that the effective interactions are well described by the orientation-dependent ML potentials.
How capture affects polymer translocation in a solitary nanopore
Authors: Seth Swarnadeep , Bhattacharya Aniket
Published: June 2022

DNA capture with high fidelity is an essential part of nanopore translocation. We report several important aspects of the capture process and subsequent translocation of a model DNA polymer through a solid-state nanopore in the presence of an extended electric field using the Brownian dynamics simulation that enables us to record statistics of the conformations at every stage of the translocation process. By releasing the equilibrated DNAs from different equipotentials, we observe that the capture time distribution depends on the initial starting point and follows a Poisson process. The field gradient elongates the DNA on its way toward the nanopore and favors a successful translocation even after multiple failed threading attempts. Even in the limit of an extremely narrow pore, a fully flexible chain has a finite probability of hairpin-loop capture, while this probability decreases for a stiffer chain and promotes single file translocation. Our in silico studies identify and differentiate characteristic distributions of the mean first passage time due to single file translocation from those due to translocation of different types of folds and provide direct evidence of the interpretation of the experimentally observed folds [M. Gershow and J. A. Golovchenko, Nat. Nanotechnol. 2, 775 (2007) and Mihovilovic et al., Phys. Rev. Lett. 110, 028102 (2013)] in a solitary nanopore. Finally, we show a new finding—that a charged tag attached at the 5′ end of the DNA enhances both the multi-scan rate and the uni-directional translocation (5′ → 3′) probability that would benefit the genomic barcoding and sequencing experiments.
A complete classification of sub-shocks in the shock structure of a binary mixture of Eulerian gases with different degrees of freedom
Authors: Ruggeri Tommaso , Taniguchi Shigeru
Published: June 2022

The shock structure in a binary mixture of polyatomic Eulerian gases with different degrees of freedom of a molecule is studied based on the multi-temperature model of rational extended thermodynamics. Since the system of field equations is hyperbolic, the shock-structure solution is not always regular, and discontinuous parts (sub-shocks) can be formed. For given values of the mass ratio and the specific heat of the constituents, we identify the possible sub-shocks as the Mach number M0 of the shock wave and the equilibrium concentration c0 of the constituents change. In the plane (c0, M0), we identify the possible regions for the sub-shock formation. The analysis is obtained to verify when the velocity of the shock wave meets a characteristic velocity in the unperturbed or perturbed equilibrium states, which gives a necessary condition for the sub-shock formation. The condition becomes necessary and sufficient when the velocity of the shock becomes greater than the maximum characteristic velocity in the unperturbed state, namely, the regions with no sub-shocks, a sub-shock for only one constituent, or sub-shocks for both constituents are comprehensively classified. The most interesting case is that the lighter molecule has more degrees of freedom than that of the heavy one. In this situation, the topology of the various regions becomes different. We also solve the system of the field equations numerically using the parameters in various regions and confirm whether the sub-shocks emerge or not. Finally, the relationship between an acceleration wave in one constituent and the sub-shock in the other constituent is explicitly derived.
Exceptional point shifted by Kerr effect in anti-parity-time symmetry system
Authors: Chen Tuoyu , Xiao Zhisong , Jiang Shuo , Li Wenxiu , Li Jincheng , Wang Yuefei , Wang Xiaochen , Huang Anping , Zhang Hao
Published: June 2022

With respect to parity-time symmetry, an anti-parity-time (APT) symmetric system exhibits much easier readout mechanism due to its real frequency splitting. Generally, such systems need to be operated at exceptional points (EPs) to obtain the best performance. However, strict conditions to locate APT symmetric systems at their EPs precisely put restraints on their practical applications. To overcome this problem, we propose a scheme to manipulate EPs in APT symmetric configuration by the Kerr effect. It is demonstrated that operating EPs by self-phase modulation alone will impede frequency splitting caused by external perturbations, while cross-phase modulation can enhance the response to measurable perturbations. We also investigate the thermal effect induced by high light intensity, which could reduce the power to manipulate EPs. This proposed scheme can pave a new way for fabricating devices based on APT symmetry.
Prediction of drag components on rough surfaces using effective models
Authors: Jain Sahaj , Sudhakar Y.
Published: June 2022

Owing to the multiscale nature and the consequent high-computational cost associated with simulations of flows over rough surfaces, effective models are being developed as a practical means of dealing with such flows. Existing effective models focus primarily on accurately predicting interface velocities using the slip length. Moreover, they are concerned mainly with flat interfaces and do not directly address the drag computation. In this work, we formulate the Transpiration-Resistance model in polar coordinates and address the challenge of computing drag components on rough surfaces. Like the slip length, we introduce two constitutive parameters called shear and pressure correction factors that encompass information about how the total drag is partitioned into viscous and pressure components. Computation of these non-empirical parameters does not necessitate solving additional microscale problems; they can be obtained from the same microscale problem used for the slip-length calculation. We demonstrate the effectiveness of the proposed parameters for the Couette flow over rough surfaces. Moreover, using the flow over a rough cylinder as an example, we present the accuracy of predicting interface velocity and drag components by comparing the effective model results with those obtained from geometry-resolved simulations. Numerical simulations presented in this paper prove that we can accurately capture both viscous and pressure drag over rough surfaces for flat- and circular-interface problems using the proposed constitutive parameters.
Ternary organic solar cells: Insights into charge and energy transfer processes
Authors: Zhang Tianyi , Gasparini Nicola
Published: June 2022

Recent advances demonstrate the efficacy of ternary strategy in organic solar cells. Such excitement is achieved by synergistic improvement in both charge dynamics and energetics. The third component serves as a bridging unit to systematically optimize the charge migration, exciton lifetime, recombination, and nanomorphology. Primarily focusing on the tactics for addressing energy transfer, charge transfer, and voltage losses, specific relationship between kinetics and energetics evolution has been thoroughly analyzed upon addition of the third component. We propose that the future design should be beyond simply complementing absorption, but rather focus on how the guest molecular could specifically address the charge and energy profile. With fine control of morphology, the maximum potential of ternary blends can be realized toward highly efficient organic solar cells.
Data-driven reduced order modeling for parametrized time-dependent flow problems
Authors: Ma Zhengxiao , Yu Jian , Xiao Ruoye
Published: June 2022

This paper proposes a nonintrusive reduced basis (RB) method based on dynamic mode decomposition (DMD) for parameterized time-dependent flows. In the offline stage, the reduced basis functions are extracted by a two-step proper orthogonal decomposition algorithm. Then, a novel hybrid DMD regression model that combines windowed DMD and optimized DMD is introduced for the temporal evolution of the RB coefficients. To improve the stability of this method for complex nonlinear problems, we introduce a threshold value to modify the DMD eigenvalues and eigenvectors. Moreover, the interpolation of the coefficients in parameter space is conducted by a feedforward neural network or random forest algorithm. The prediction of the RB solution at a new time/parameter value can be recovered at a low computational cost in the online stage, which is completely decoupled from the high-fidelity dimension. We demonstrate the performance of the proposed model with two cases: (i) laminar flow past a two-dimensional cylinder and (ii) turbulent flow around a three-dimensional SD7003 airfoil. The results show reasonable efficiency and robustness of this novel reduced-order model.
A two-step search and run response to gradients shapes leukocyte navigation in vivo
Authors: Georgantzoglou Antonios , Poplimont Hugo , Walker Hazel A. , Lämmermann Tim , Sarris Milka
Published: June 2022

Migrating cells must interpret chemical gradients to guide themselves within tissues. A long-held principle is that gradients guide cells via reorientation of leading-edge protrusions. However, recent evidence indicates that protrusions can be dispensable for locomotion in some contexts, raising questions about how cells interpret endogenous gradients in vivo and whether other mechanisms are involved. Using laser wound assays in zebrafish to elicit acute endogenous gradients and quantitative analyses, we demonstrate a two-stage process for leukocyte chemotaxis in vivo: first a “search” phase, with stimulation of actin networks at the leading edge, cell deceleration, and turning. This is followed by a “run” phase, with fast actin flows, cell acceleration, and persistence. When actin dynamics are perturbed, cells fail to resolve the gradient, suggesting that pure spatial sensing of the gradient is insufficient for navigation. Our data suggest that cell contractility and actin flows provide memory for temporal sensing, while expansion of the leading edge serves to enhance gradient sampling.
Experimental Test of Contextuality Based on State Discrimination with a Single Qubit
Authors: Zhang Qiuxin , Zhu Chenhao , Wang Yuxin , Ding Liangyu , Shi Tingting , Zhang Xiang , Zhang Shuaining , Zhang Wei
Published: June 2022

Exploring quantum phenomena beyond predictions of any classical model has fundamental importance to understand the boundary of classical and quantum descriptions of nature. As a typical property that a quantum system behaves distinctively from a classical counterpart, contextuality has been studied extensively and verified experimentally in systems composed of at least three levels (qutrit). Here we extend the scope of experimental test of contextuality to a minimal quantum system of only two states (qubit) by implementing the minimum error state discrimination on a single 171Yb+ ion. We observe a substantial violation of a no-go inequality derived by assuming non-contextuality, and firmly conclude that the measured results of state discrimination cannot be reconciled with any non-contextual description. We also quantify the contextual advantage of state discrimination and the tolerance against quantum noises.
Study of electron impact elastic scattering from Kr@C60 and Xe@C60 using a fully relativistic approach
Authors: Mahato Dibyendu , Sharma Lalita , Baral Saumyashree , Saha Subhasish , Jose Jobin , Srivastava Rajesh
Published: June 2022

In the present work, a detailed study has been reported on electron impact elastic scattering from krypton (Kr) and xenon (Xe) atoms when confined in two different types of C60 potentials viz (a) hard annular square well (ASW) and (b) diffused Gaussian annular square well (GASW). The Dirac equations are solved using these potentials for encaged Kr and Xe in C60. First, bound state Dirac–Fock wave functions of these encaged Kr and Xe atoms are found by utilizing modified general relativistic atomic structure package and thereafter, the charge densities and static potentials of the endohedral Kr@C60 and Xe@C60 are obtained. Further, using these, the Dirac equations are solved by the relativistic partial wave phase shift analysis method and the scattering amplitudes in terms of phase shifts are obtained. Thereafter, the electron elastic differential and integrated cross sections of Kr@C60 and Xe@C60 along with the C60 are calculated in the range of 0.1–15 eV incident electron energies. Presently, no experimental and theoretical results are available to compare our electron scattering cross section results from Kr@C60 and Xe@C60; thus, we have shown the cross section results obtained from ASW and GASW potential and compared them.
Catalyst-free production of ammonia by means of interaction between a gliding arc plasma and water surface
Authors: Indumathy B , Ananthanarasimhan J , Rao Lakshminarayana , Yugeswaran S , Ananthapadmanabhan P V
Published: June 2022

This work reports a study on using a gliding arc plasma reactor to produce ammonia from nitrogen plasma and a water medium without using a catalyst. During the gliding arc plasma discharge, a plasma plume was formed, and vibrational and rotational excitation was observed at the tip of the plasma plume that touched the water below. This arrangement helped the formation of ammonia. The ammonia concentration was 2.12–5.69 ppm, and its production rate varied in the range of 0.63–0.68 mg h−1, having energy efficiency in the range of 0.0249–0.0268 g-NH3 kWh−1, depending on the plasma exposure time. The vibrational temperature increased from 2632 K (near the gas entry zone) to 3778 K (at the tip of the plasma plume interacting with the water), corroborated by the enhanced distribution of electron energy for vibration excitation (≈24%), compared to that for electronic excitation (≈0.03%). The electron temperature dropped from 1.38 eV to 0.76 eV at the plasma zone interacting with the water. This work demonstrates the application of gliding arc plasmas to generate eco-friendly ammonia (green ammonia), and the reactor proves to be promising for further optimization in the future.
Low-profile linear polarization conversion metasurfaces using degenerate modes for high selectivity
Authors: Du Junsa , Deng Lianwen , Qiu Leilei , Tang Chao , Li Chen , Li Yuhan , Gao Xiaohui , Huang Shengxiang
Published: June 2022

In this paper, two ultrathin polarization conversion metasurfaces (PCMs) were designedfor linear polarization of electromagnetic waves. A method of controlling degenerate modes was applied for enhanced selectivity. The surface resonator is a square patch etched with orthogonal cross-slots. Adjustment of the cross-slot size is beneficial as it introduces a perturbation factor and controls the splitting of the degenerate modes. The constructed dual-mode single-band and four-mode dual-band PCMs with different pairs of degenerate modes can efficiently reflect linear polarized waves to the orthogonal polarization counterpart in the range of 5.89–6.4 GHz and 5.88–6.30 GHz/8.19–8.59 GHz, respectively. Current distribution and an equivalent circuit model were studied to reveal the polarization conversion mechanism. Finally, experiments were implemented to verify the near unity cross-polarization conversion efficiency at the corresponding bands. Given the PCM’s advanced performance of low profile and high selectivity, it has great potential applications in controlling the polarization state of microwaves.
Methodologies for model parameterization of virtual CTs for measurement uncertainty estimation
Authors: Binder Felix , Bircher Benjamin A , Laquai René , Küng Alain , Bellon Carsten , Meli Felix , Deresch Andreas , Neuschaefer-Rube Ulrich , Hausotte Tino
Published: June 2022

X-ray computed tomography (XCT) is a fast-growing technology for dimensional measurements in industrial applications. However, traceable and efficient methods to determine measurement uncertainties are not available. Guidelines like the VDI/VDE 2630 Part 2.1 suggest at least 20 repetitions of a specific measurement task, which is not feasible for industrial standards. Simulation-based approaches to determine task specific measurement uncertainties are promising, but require closely adjusted model parameters and an integration of error sources like geometrical deviations during a measurement. Unfortunately, the development of an automated process to parameterize and integrate geometrical deviations into XCT models is still an open issue. In this work, the whole processing chain of dimensional XCT measurements is taken into account with focus on the issues and requirements to determine suitable parameters of geometrical deviations. Starting off with baseline simulations of different XCT systems, two approaches are investigated to determine and integrate geometrical deviations of reference measurements. The first approach tries to iteratively estimate geometric deviation parameter values to match the characteristics of the missing error sources. The second approach estimates those values based on radiographs of a known calibrated reference object. In contrast to prior work both approaches only use a condensed set of parameters to map geometric deviations. In case of the iterative approach, some major issues regarding unhandled directional dependencies have been identified and discussed. Whereas the radiographic method resulted in task specific expanded measurements uncertainties below one micrometre even for bi-directional features, which is a step closer towards a true digital twin for uncertainty estimations in dimensional XCT.
A novel resistivity measurement method for a homogeneous cylinder shape based on the vdP configuration
Authors: Ma Deliang , Chen Mengfei , Xie Yifei , Feng Huaiping , Chang Jianmei
Published: June 2022

The electrical resistivity method for a cylinder shape is an essential method for reflecting physical properties. However, the use of a nondestructive resistivity method with the circumferential cross-section arrangement for working components remains challenging. This paper provides a simple novel resistivity method for a cylinder shape based on the van der Pauw configuration, with four electrodes placed near the middle cross-section layer of shape. First, the theoretical solution formulae for the electrostatic potential function in the cylindrical coordinate system are derived. Then, the effect of the electrode and shape size is analysed. The results show that the electrode height is less than 1% of the cylinder height and the radian angle is less than 10°, where the electrode size effect on the correction factor (CF) can be ignored, and CF rarely depends on the cylinder shape. Finally, a prototype is designed, and the proposed method is verified in laboratory tests using geomaterials. The performance of the proposed method for fine soil at high moisture contents is found to be better than that at low moisture contents.
Global existence of weak solutions to viscoelastic phase separation: part II. Degenerate case
Authors: Brunk Aaron , Lukáčová-Medvid’ová Mária
Published: June 2022

The aim of this paper is to prove global in time existence of weak solutions for a viscoelastic phase separation. We consider the case with singular potentials and degenerate mobilities. Our model couples the diffusive interface model with the Peterlin–Navier–Stokes equations for viscoelastic fluids. To obtain the global in time existence of weak solutions we consider appropriate approximations by solutions of the viscoelastic phase separation with a regular potential and build on the corresponding energy and entropy estimates.
Doubly nonlinear Schrödinger ground states on metric graphs
Authors: Boni Filippo , Dovetta Simone
Published: June 2022

We investigate the existence of ground states at prescribed mass on general metric graphs with half-lines for focussing doubly nonlinear Schrödinger equations involving both a standard power nonlinearity and delta nonlinearities located at the vertices. The problem is proved to be sensitive both to the topology and to the metric of the graph and to exhibit a phenomenology richer than in the case of the sole standard nonlinearity considered by Adami et al (2015 Calc. Var.
54 743–61; 2016 J. Funct. Anal.
271 201–23). On the one hand, we identify various topological features responsible for existence/non-existence of doubly nonlinear ground states in specific mass regimes. On the other hand, we describe the role of the metric in determining the interplay between these different topological properties.
Development and implementation of an automatic air delineation technique for MRI-guided adaptive radiation therapy
Authors: Ahunbay Ergun , Parchur Abdul K , Paulson Eric , Chen Xinfeng , Omari Eenas , Li X Allen
Published: June 2022

Objective. Auto-delineation of air regions on daily MRI for MR-guided online adaptive radiotherapy (MRgOART) of abdominal tumors is challenging since the air packets occur randomly and their MR intensities can be similar to some other tissue types. This work reports a new method to auto-delineate air regions on MRI. Approach. The proposed method (named DIFF method) consists of (1) generating a combined volume V

comb
, which is a union of the air-containing organs on a reference MR image offline, (2) transferring V

comb
from the reference MR to a daily MR via DIR, (3) combining the transferred V

comb
with a region of high DIR inaccuracy, and (4) applying a threshold to the obtained final combined volume to generate the air volumes. The high DIR inaccuracy region was calculated from the absolute difference between the deformed daily and the reference images. This method was tested on 36 abdominal daily MRI sets acquired from 7 patients on a 1.5 T MR-Linac. The performance of DIFF was compared with alternative auto-air generation methods that (1) does not account for DIR inaccuracies, and (2) uses rigid registration instead of DIR. Main results. The results show that the proposed DIFF method can be fully automated and can be executed within 25 s. The Dice similarity coefficient of manual and DIFF auto-generated air contours was >92% for all cases, while it was 90% for the alternative auto-delineation methods. Dosimetrically, the auto-generated air regions using DIFF resulted in practically identical DVHs as those generated by using manual air contours. Significance. The DIFF method is robust and accurate and can be implemented to automatically consider the inter- and intra- fractional air volume variations during MRgOART for abdominal tumors. The use of DIFF method improves dosimetric accuracy as compared to other methods, especially beneficial for the patients with large daily abdominal air volume variations.
Self-supervised learning for multi-center magnetic resonance imaging harmonization without traveling phantoms
Authors: Chang Xiao , Cai Xin , Dan Yibo , Song Yang , Lu Qing , Yang Guang , Nie Shengdong
Published: June 2022

Objective. With the progress of artificial intelligence (AI) in magnetic resonance imaging (MRI), large-scale multi-center MRI datasets have a great influence on diagnosis accuracy and model performance. However, multi-center images are highly variable due to the variety of scanners or scanning parameters in use, which has a negative effect on the generality of AI-based diagnosis models. To address this problem, we propose a self-supervised harmonization (SSH) method. Approach. Mapping the style of images between centers allows harmonization without traveling phantoms to be formalized as an unpaired image-to-image translation problem between two domains. The mapping is a two-stage transform, consisting of a modified cycle generative adversarial network (cycleGAN) for style transfer and a histogram matching module for structure fidelity. The proposed algorithm is demonstrated using female pelvic MRI images from two 3 T systems and compared with three state-of-the-art methods and one conventional method. In the absence of traveling phantoms, we evaluate harmonization from three perspectives: image fidelity, ability to remove inter-center differences, and influence on the downstream model. Main results. The improved image sharpness and structure fidelity are observed using the proposed harmonization pipeline. It largely decreases the number of features with a significant difference between two systems (from 64 to 45, lower than dualGAN: 57, cycleGAN: 59, ComBat: 64, and CLAHE: 54). In the downstream cervical cancer classification, it yields an area under the receiver operating characteristic curve of 0.894 (higher than dualGAN: 0.828, cycleGAN: 0.812, ComBat: 0.685, and CLAHE: 0.770). Significance. Our SSH method yields superior generality of downstream cervical cancer classification models by significantly decreasing the difference in radiomics features, and it achieves greater image fidelity.
Two plasmon decay instability stimulated by large-incidence-angle laser in inertial confinement fusion
Authors: Lian C-W , Ji Y , Yan R , Cao S-H , Ren C , Wan Z-H , Yang D , Ding Y-K , Zheng J
Published: June 2022

The two-plasmon-decay instability (TPD) in the large-incidence-angle regime is studied via fluid and particle-in-cell (PIC) simulations. It is found that the TPD threshold in this regime within a narrow incidence angle range close to 60∘ can be orders of magnitude lower than the normal-incidence threshold. A threshold formula is proposed for this regime and is verified by fluid and PIC simulations. PIC simulations show significant laser absorption and energetic electron generation once TPD is excited. The incident angle and the laser spot size have a significant influence on the TPD in the large-incidence-angle regime. The low threshold and significant hot electron generation in this regime pose potentially unexpected preheating risks to inertial confinement fusion.
Magnetised and unmagnetized axisymmetric particle-in-cell simulations of ion energy distributions in cathodic vacuum arcs
Authors: Ryan Alexander , Bilek Marcela , Cairns Iver H , McKenzie David R
Published: June 2022

Cathodic arcs are electrical discharges consisting of a succession of discrete pulses of energetic plasma travelling from the surface of a cathode toward an anode. Currently, there are no vacuum arc simulations where spots are continuously generated with a set frequency, including the far-field plasma jet, with the inclusion of kinetic behaviour for both ions and electrons. The VSim 11 particle-in-cell software was used to simulate specific vacuum arcs as axisymmetric, electrostatic, and fully kinetic, from the initial generation of each cathode spot to the streaming plasma discharge at a far field, validating the predictions against experimental data. The models were configured to match the experimental arc gun of Zohrer et al and the Mevva V experiment with the cathode materials Al and Nb. The ion and electron velocity data were collected at the far edge of the simulation domain, analogous to a physical energy detector. The simulations successfully predicted the evolution of ion charge state energy distributions, showing peak unmagnetized ion energies that agree with prior experimental data, resulting in a mean error of 3% for Al and Nb. A peak in the electrostatic potential is observed above the cathode surface, supporting the potential hump theory as the cause of the higher-than-expected ion energies observed in cathodic arc discharges. Lower than expected relative energies between ion charge states are observed, matching prior experimental results, with this coupling of ion charge states attributed to non-stationary electrostatic wave–particle interactions, as the use of collisionless simulations rules out Coulombic ion friction. Magnetised simulations incorporated a statically powered short solenoid equivalent to the coil used in the Mevva V experiment to create a diverging magnetic nozzle. The magnetised simulation results demonstrate an annular jet of magnetically confined plasma and indicate an increase in nonstationary electrostatic effects including wave–particle interactions.
The Gamow shell model with realistic interactions: a theoretical framework for ab initio nuclear structure at drip-lines
Authors: Michel Nicolas , Li Jianguo , Xu Furong
Published: June 2022

Ab initio approaches are among the most advanced models to solve the nuclear many-body problem. In particular, the no-core–shell model and many-body perturbation theory have been recently extended to the Gamow shell model framework, where the harmonic oscillator basis is replaced by a basis bearing bound, resonance and scattering states, i.e. the Berggren basis. As continuum coupling is included at basis level and as configuration mixing takes care of inter-nucleon correlations, halo and resonance nuclei can be properly described with the Gamow shell model. The development of the no-core Gamow shell model and the introduction of the

Q

¯

ˆ

-box method in the Gamow shell model, as well as their first ab initio applications, will be reviewed in this paper. Peculiarities compared to models using harmonic oscillator bases will be shortly described. The current power and limitations of ab initio Gamow shell model will also be discussed, as well as its potential for future applications.