bluuebunny/crossref_metadata_2025 huggingface dataset:
A transnational multilingual language learning journey
Authors: Massó Marisol , De Costa Peter
Published: June 2023

This study presents the case of a multilingual refugee (Maji) of Kirundi, Swahili, French, and English, from Burundi living in the U.S., and examines the language ideologies and identities embedded in his transnational narratives. We analyze our focal participant’s multi-layered transnational experiences using Darvin and Norton’s (2015) model of investment that foregrounds the intersection of ideology, capital, and identity. Specifically, we center on dominant ideologies in Maji’s discourse and how he negotiated his ethnic, social class, and gendered identities. Our findings revealed that Maji, who adhered to discourses that promoted the English superiority, the prestige of dialectal forms of Swahili, Spanish, and English, and English as a global commodity displayed his awareness of language hierarchies and dominance. Yet, Maji, who drew on French for meaning-making, displayed contradictory ideas by framing French as a useless language in the U.S. as compared to English. Our study sheds light on the complexity of multilinguals’ identity construction and discusses pedagogical implications on how to support language minority students’ multilingualism.
Material, competence and meaning in the fansub community
Authors: Xueni Zhang , Binghan Zheng
Published: June 2023

Previous investigations into fansub groups have focused on their internal coherence as communities of practice and
external links to technological affordances, but research on how fansubbers interact with their social and material surroundings
is limited. This article reports on a netnographic study that showcases a novice fansubber’s construction of translating
experience. It employs practice theory to describe the composition of the fansub activity through the eyes of the netnographer as
a newcomer. This study illustrates the undertaking of translation tasks in this fansub group as co-mediated by the availability
and reproduction of materials, interaction between previously acquired and newly gained knowledge, and emergence of meanings
through membership construction. It addresses an integration of practice theory and ethnography as a promising approach to tapping
the situatedness of translation.
Monitoring of root gap change based on electrical signals of flux-cored arc welding using random convolution kernel transform
Authors: Jang Junmyoung , Lee Jaeheon , Lee Jaeyoung , Park Sang Rin , Kim Jin-young , Kim Young-Beom , Lee Seung Hwan
Published: June 2023

A monitoring technique for detecting changes in the root gap of butt joints during the flux-cored arc welding (FCAW) was proposed. FCAW experiments were conducted for both increasing and decreasing root gap conditions, and current and voltage were measured during the root-pass welding. The measured time series signals were used as input data for training Random Convolution Kernel Transform (ROCKET) algorithm, which consists of a feature extractor with multiple random kernels, and a linear classifier. A univariate model using current and voltage, respectively, and a multivariate model using both were compared, and the multivariate model showed the highest classification accuracy of 96.2%. Moreover, the classification errors were investigated by correlating the geometry of the root bead with the measured signals.
Friction stir welding of thick 7175 aluminium alloy plates for deepwater riser applications
Authors: Wang Tianhao , Reza-E-Rabby Md , Das Hrishikesh , Grant Glenn J. , Whalen Scott
Published: June 2023

To substantially reduce the cost of extracting petroleum from ultra-deepwater sources, manufacturing risers from 7175 aluminium (Al) alloys rather than steels is being considered. Friction stir welding (FSW), a solid-phase joining technique, is widely applied to 7XXX Al alloys because its mechanical properties are retained within the nugget zone. And, the primary technical objective of the current study is the development of high-strength, corrosion-resistant weldments that connect 7175 Al riser flanges and pipes. However, as the welding thickness increases, the welding speed can be greatly impeded, which lowers the manufacturing efficiency and weakens the mechanical properties in the heat affected zone (next to the nugget). Therefore, obtaining high-performance thick plate 7175 Al alloy joints via FSW is challenging. To overcome this dilemma, the current work optimises the tool design and welding parameters for achieving high-performance joints between 25.4 mm thick 7175 Al alloy plates in butt joint configuration.
Negative-to-Positive Tunnel Magnetoresistance in van der Waals Fe3GeTe2/Cr2Ge2Te6/Fe3GeTe2 Junctions
Authors: Wang Zi-Ao , Zhang Xiaomin , Zhu Wenkai , Yan Faguang , Liu Pengfei , Yuan Zhe , Wang Kaiyou
Published: June 2023

The emergent van der Waals magnetic material is a promising component for spintronic devices with novel functionalities. Here, we report a transition of negative-to-positive magnetoresistance in Fe3GeTe2/Cr2Ge2Te6/Fe3GeTe2 van der Waals all-magnetic tunnel junctions with increasing the applied bias voltage. A negative magnetoresistance is observed first in Fe3GeTe2/Cr2Ge2Te6/Fe3GeTe2 tunnel junctions, where the resistance with antiparallel aligned magnetization of two Fe3GeTe2 electrodes is lower than that with parallel alignment, which is due to the opposite spin polarizations of two Fe3GeTe2 electrodes. With the bias voltage increasing, the spin polarization of the biased Fe3GeTe2 electrode is changed so that the spin orientations of two Fe3GeTe2 electrodes are the same. Our experimental observations are supported by the calculated spin-dependent density of states for Fe3GeTe2 electrodes under a finite bias. The significantly bias voltage-dependent spin transport properties in van der Waals magnetic tunnel junctions open a promising route for designing electrical controllable spintronic devices based on van der Waals magnets.
Exotic black hole thermodynamics in third-order Lovelock gravity
Authors: Hull Brayden , Simovic Fil
Published: June 2023

The generalisation of Birkhoff’s theorem to higher dimensions in Lovelock gravity allows for black hole solutions with horizon geometries of non-constant curvature. We investigate thermodynamic aspects of these ‘exotic’ black hole solutions, with a particular emphasis on their phase transitions. We consider an extended phase space where the cosmological constant acts as a thermodynamic pressure, and examine both uncharged and U(1) charged solutions. In d = 7, black hole solutions are restricted to having constant curvature horizon base manifolds. Uncharged d = 7 black holes possess novel triple point phenomena analogous to those recently uncovered in exotic d = 6 black holes in Gauss–Bonnet gravity, while their charged counterparts generically undergo small-large black hole phase transitions. In d = 8, we find that both charged and uncharged black holes exhibit triple point behaviour and small-large black hole transitions. We also show that a wide range of ‘exotic’ horizon geometries can be ruled out due to the appearance of naked singularities.
Cosmology in Minkowski space
Authors: Lombriser Lucas
Published: June 2023

Theoretical and observational challenges to standard cosmology such as the cosmological constant problem and tensions between cosmological model parameters inferred from different observations motivate the development and search of new physics. A less radical approach to venturing beyond the standard model is the simple mathematical reformulation of our theoretical frameworks underlying it. While leaving physical measurements unaffected, this can offer a reinterpretation and even solutions of these problems. In this spirit, metric transformations are performed here that cast our Universe into different geometries. Of particular interest thereby is the formulation of cosmology in Minkowski space. Rather than an expansion of space, spatial curvature, and small-scale inhomogeneities and anisotropies, this frame exhibits a variation of mass, length and time scales across spacetime. Alternatively, this may be interpreted as an evolution of fundamental constants. As applications of this reframed cosmological picture, the naturalness of the cosmological constant is reinspected and promising candidates of geometric origin are explored for dark matter, dark energy, inflation and baryogenesis. An immediate observation thereby is the apparent absence of the cosmological constant problem in the Minkowski frame. The formalism is also applied to identify new observable signatures of conformal inhomogeneities, which have been proposed as simultaneous solution of the observational tensions in the Hubble constant, the amplitude of matter fluctuations, and the gravitational lensing amplitude of cosmic microwave background anisotropies. These are found to enhance redshifts to distant galaxy clusters and introduce a mass bias with cluster masses inferred from gravitational lensing exceeding those inferred kinematically or dynamically.
The stable and unstable oscillations of a rod attached to many springs
Authors: Abdullah Mikrajuddin , Rahmayanti Handika Dany , Yuliza Elfi , Munir Rahmawati
Published: June 2023

The oscillation equations of a multi-spring system connected to a rod are developed. Oscillations can be stable or unstable depending on the distribution of the spring constant and the number of springs. The symmetrical spring distribution with respect to the rod center tends to stabilize. The system becomes more stable as the number of springs increases. The equations of motion are identified to satisfy the Mathieu’s equation. The system could be thought of as a rough imitation of the crazy bamboo attraction, a traditional attraction by old civilization that is frequently associated with the mystical phenomenon. One spring represents one performer. The behavior of the performer’s force (opposite to the direction of the bamboo movement and providing a stronger force as the displacement of the bamboo increases) is similar to that of the spring force.
Solving an inverse source problem by deep neural network method with convergence and error analysis
Authors: Zhang Hui , Liu Jijun
Published: June 2023

For the inverse source problem of an elliptic system using noisy internal measurement as inversion input, we approximate its solution by neural network function, which is obtained by optimizing an empirical loss function with appropriate regularizing terms. We analyze the convergence of the general loss from noisy inversion input data in deep Galerkin method by the regularizing empirical loss function. Based on the upper bound of the expected loss function by its regularizing empirical form, we establish the upper bound of the expected loss function at the minimizer of the regularizing empirical noisy loss function in terms of the number of sampling points as well as the noise level quantitatively, for suitably chosen regularizing parameters and regularizing terms. Then, by specifying the number of sampling points in terms of noise level of inversion input data, we establish the error orders representing the difference between the neural network solution and the exact one, under some a-priori restrictions on the source. Finally, we give numerical implementations for several examples to verify our theoretical results.
Mechanical energy harvesting in traffic environment and its application in smart transportation
Authors: Du Ronghua , Xiao Jun , Chang Sideng , Zhao Linchuan , Wei Kexiang , Zhang Wenming , Zou Hongxiang
Published: June 2023

The concept of green and sustainable development is driving the convergence of transportation systems and energy technologies. New energy harvesting technology (EHT) is an important way of the development in the green intelligent transportation system. Comparing with the power supply via batteries or cables, it has the advantages of convenient, sustainable, green and low carbon to harvest mechanical energy from the traffic environment and convert it into electrical energy to power the widely distributed small electromechanical systems. There are many studies on mechanical energy harvesting in traffic environment, few of them have comprehensively discussed these studies and their applications in the intelligent transportation. This paper first outlines the principles, methods, and energy management strategies of the mechanical energy harvesting in the traffic environment. The advantages, disadvantages, and applicability of various EHTs are comprehensively and systematically analyzed from vehicle and road dimensions. The applications of EHT was discussed includes: self-powered traffic control, self-powered vehicle-road collaboration and self-powered health monitoring of traffic infrastructure. Finally, the challenges and prospects of mechanical EHT and applications in the traffic environment are discussed. Mechanical energy harvesting in traffic environment has broad application prospects in intelligent transportation, while improving the output power and reliability of the energy harvesting system is the key to its wide application in intelligent transportation systems.
On the interplay of body-force distributions and flow speed for dielectric-barrier discharge plasma actuators
Authors: Hehner Marc T , Coutinho Gonçalo , Santos Pereira Ricardo B , Benard Nicolas , Kriegseis Jochen
Published: June 2023

The dielectric-barrier discharge plasma actuator is a well-established device commonly operated in boundary-layer airflows for active flow control. In the present experimental investigation, their ability to cause momentum transfer to the surrounding fluid is analyzed by means of spatio-temporal body-force distributions in both quiescent air and external airflow conditions. The work is motivated by the limitation to quiescent-air operating conditions of frequent previous efforts. Available analytical velocity-information-based force derivation approaches are contrasted to investigate the actuator performance under conditions of their area of application. Results of body force in quiescent air, in agreement with literature, confirm the major taken assumption for Navier–Stokes-based body-force formulations—a negligible pressure gradient. However, the previous circumstance turns out as an invalid assumption for plasma actuation encountering an external airflow. These outcomes coincide with the findings in the numerical work of (2015 Numerical investigation of plasma-actuator force-term estimations from flow experiments J. Phys. D: Appl. Phys.
48 395203), following the recommendation to apply a vorticity-equation-based approach under such conditions. Furthermore, the shape of the spatio-temporal body-force distribution is observed to undergo changes when the airflow speed increases. On the other hand, the integral force magnitude is found to remain approximately constant. Moreover, the choice of phase resolution of the discharge cycle has an implication on the accuracy of the temporal force evolution, therefore, clarifying the importance of a priori defining the type of body-force analysis in an experiment; i.e. integral force magnitude, time-averaged or time-resolved evaluation. As a promising finding of utmost importance for the actuator performance, the actuator remains as effective as in quiescent air under presence of the external airflow, which immediately renders the actuator fluid-mechanic efficiency to increase for increasing airflow speed.
Molecular dynamics simulation of cathode crater formation in the cathode spot of vacuum arcs
Authors: Yang Haonan , Shen Shuhang , Xu Ruoyu , Zhou Mingyu , Yan Joseph , Wang Zhongdong
Published: June 2023

A three-dimensional model based on molecular dynamics has been developed to describe the formation of a single cathode spot in vacuum arcs. The formation of the cathode spot is assumed to be controlled by the plasma ions, the effect of which is simulated in LAMMPS through the process of ion bombardment. The cathode is represented by structured copper atoms, while the ions are continuously injected into the domain with a certain velocity towards the cathode surface. Ion bombardment leads to the appearance of a crater, which is caused by the accumulation of pressure effect against the relaxation of substrate temperature. The size of the crater is found to be determined by the spatial distribution of the injected ions. The formation of the cathode spot is also scrutinised by electron emission from the cathode surface with variable surface temperature during the cathode spot development process. In addition, the evaporated atoms forming the metal vapour are observed. This study provides a description of the formation of the cathode spot at microscale, which shall be helpful to further studies of the arc rooting and arc contact (electrode) erosion in vacuum environment.
Effects of the voltage ramp rate on the conduction characteristics of HfO2-based resistive switching devices
Authors: García H , Vinuesa G , García-Ochoa E , Aguirre F L , González M B , Jiménez-Molinos F , Campabadal F , Roldán J B , Miranda E , Dueñas S , Castán H
Published: June 2023

Memristive devices have shown a great potential for non-volatile memory circuits and neuromorphic computing. For both applications it is essential to know the physical mechanisms behind resistive switching; in particular, the time response to external voltage signals. To shed light in these issues we have studied the role played by the applied voltage ramp rate in the electrical properties of TiN/Ti/HfO2/W metal–insulator–metal resistive switching devices. Using an ad hoc experimental set-up, the current–voltage characteristics were measured for ramp rates ranging from 100 mV s−1–1 MV s−1. These measurements were used to investigate in detail the set and reset transitions. It is shown that the highest ramp rates allow controlling the resistance values corresponding to the intermediate states at the very beginning of the reset process, which is not possible by means of standard quasistatic techniques. Both the set and reset voltages increase with the ramp rate because the oxygen vacancies movement is frequency dependent so that, when the ramp rate is high enough, the conductive filaments neither fully form nor dissolve. In agreement with Chua’s theory of memristive devices, this effect causes the device resistance window to decrease as the ramp rate increases, and even to vanish for very high ramp rates. Remarkably, we demonstrate that the voltage ramp rate can be straightforwardly used to control the conductance change of the switching devices, which opens up a new way to program the synaptic weights when using these devices to mimic synapses for neuromorphic engineering applications. Moreover, the data obtained have been compared with the predictions of the dynamic memdiode model.
Temperature dependence of semi-hard iron silicide rare-earth free magnet
Authors: Siraj Haq , Hong Jisang
Published: June 2023

Searching for rare-earth free permanent magnet attracts extensive research interests due to diverse technological applications and other subtle issues. Here, the temperature dependent magnetic properties of Fe5SiC structure are explored. The Fe5SiC has a critical temperature of 710 K with perpendicular magnetic anisotropy. The magnetic anisotropy constant and coercive field are monotonically decreased with increasing temperature. For instance, the magnetic anisotropy constant is 0.42 MJ m−3 at zero Kelvin and reduced to 0.24 MJ m−3 and 0.06 MJ m−3 at 300 K and 600 K. The coercive field becomes 0.7 T at 0 K. With increasing the temperatures, it is suppressed to 0.42 T and 0.20 T at 300 K and 600 K, respectively. Overall, the Fe5SiC system has a (BH)max of 417 kJ m−3 at zero Kelvin. The (BH)max is decreased at high temperature. Nonetheless, we obtain the (BH)max of 234 kJ m−3 at 300 K. Since the Fe5SiC shows better permanent magnetic (PM) property than the conventional ferrites and also CeCo5. This finding may indicate that the Fe5SiC can be a potential candidate as a Fe-based gap PM between ferrite and Nd–Fe–B (or Sm–Co) at room temperature.
Effect of internal interface layer on dielectric properties of doped Ba0.6Sr0.4TiO3 thin films and its simulation in filters
Authors: Wang Hong-zhe , Li Bo
Published: June 2023

Effect of the internal interface layer on the dielectric properties of doped Ba0.6Sr0.4TiO3 (BST) films and their simulation research in filters. Based on the interfacial effect in the multi-layer ferroelectric thin film, a different number of internal interface layers was proposed and introduced into the Ba0.6Sr0.4TiO3 thin film. First, Ba0.6Sr0.4Ti0.99Zn0.01O3 (ZBST) sol and Ba0.6Sr0.4Ti0.99Mg0.01O3 (MBST) sols were prepared using the sol-gel method. Ba0.6Sr0.4Ti0.99Zn0.01O3/Ba0.6Sr0.4Ti0.99Mg0.01O3/Ba0.6Sr0.4Ti0.99Zn0.01O3 thin films with 2 layer internal interface layer, 4 layer internal interface layer and 8 layer internal interface layer were designed and prepared (I2, I4, I8). The effects of the internal interface layer on the structure, morphology, dielectric properties, and leakage current behavior of the films were studied. The results showed that all the films were of the cubic perovskite BST phase and had the strongest diffraction peak in the (110) crystal plane. The surface composition of the film was uniform, and there was no cracked layer. When the bias of the applied DC field was 600 kV cm−1, the high-quality factor values of the I8 thin film at 10 MHz and 100 kHz were 111.3 and 108.6, respectively. The introduction of the internal interface layer changed the leakage current of the Ba0.6Sr0.4TiO3 thin film, and the I8 thin film exhibited the minimum leakage current density. The I8 thin-film capacitor was used as the tunable element to design a fourth-step ‘tapped’ complementary bandpass filter. When the permittivity was reduced from 500 to 191, the central frequency-tunable rate of the filter was 5.7%.
Dual-contrast photon-counting micro-CT using iodine and a novel bismuth-based contrast agent
Authors: Amato Carlo , Susenburger Markus , Lehr Samuel , Kuntz Jan , Gehrke Nicole , Franke Danielle , Thüring Thomas , Briel Andreas , Brönnimann Christian , Kachelrieß Marc , Sawall Stefan
Published: June 2023

Objectives. To characterize for the first time in vivo a novel bismuth-based nanoparticular contrast agent developed for preclinical applications. Then, to design and test in vivo a multi-contrast protocol for functional cardiac imaging using the new bismuth nanoparticles and a well-established iodine-based contrast agent. Approach. A micro-computed tomography scanner was assembled and equipped with a photon-counting detector. Five mice were administered with the bismuth-based contrast agent and systematically scanned over 5 h to quantify the contrast enhancement in relevant organs of interest. Subsequently, the multi-contrast agent protocol was tested on three mice. Material decomposition was performed on the acquired spectral data to quantify the concentration of bismuth and iodine in multiple structures, e.g. the myocardium and vasculature. Main results. In the vasculature, the bismuth agent provides a peak enhancement of 1100 HU and a half-life of about 260 min. After the injection, it accumulates in the liver, spleen and intestinal wall reaching a CT value of 440 HU about 5 h post injection. Phantom measurements showed that the bismuth provides more contrast enhancement than iodine for a variety of tube voltages. The multi-contrast protocol for cardiac imaging successfully allowed the simultaneous decomposition of the vasculature, the brown adipose tissue and the myocardium. Significance. The new bismuth-based contrast agent was proven to have a long circulation time suitable for preclinical applications and to provide more contrast than iodine agents. The proposed multi-contrast protocol resulted in a new tool for cardiac functional imaging. Furthermore, thanks to the contrast enhancement provided in the intestinal wall, the novel contrast agent may be used to develop further multi contrast agent protocols for abdominal and oncological imaging.
Hydrogenated amorphous silicon high flux x-ray detectors for synchrotron microbeam radiation therapy
Authors: Large Matthew J , Bizzarri Marco , Calcagnile Lucio , Caprai Mirco , Caricato Anna Paola , Catalano Roberto , Cirrone Giuseppe A P , Croci Tommaso , Cuttone Giacomo , Dunand Sylvain , Fabi Michele , Frontini Luca , Gianfelici Benedetta , Grimani Catia , Ionica Maria , Kanxheri Keida , Lerch Michael L F , Liberali Valentino , Martino Maurizio , Maruccio Giuseppe , Mazza Giovanni , Menichelli Mauro , Monteduro Anna Grazia , Moscatelli Francesco , Morozzi Arianna , Pallotta Stefania , Papi Andrea , Passeri Daniele , Pedio Maddalena , Petringa Giada , Peverini Francesca , Piccolo Lorenzo , Placidi Pisana , Quarta Gianluca , Rizzato Silvia , Rossi Alessandro , Rossi Giulia , de Rover Vincent , Sabbatini Federico , Servoli Leonello , Stabile Alberto , Talamonti Cinzia , Tosti Luca , Villani Mattia , Wheadon Richard J , Wyrsch Nicolas , Zema Nicola , Petasecca Marco
Published: June 2023

Objective. Microbeam radiation therapy (MRT) is an alternative emerging radiotherapy treatment modality which has demonstrated effective radioresistant tumour control while sparing surrounding healthy tissue in preclinical trials. This apparent selectivity is achieved through MRT combining ultra-high dose rates with micron-scale spatial fractionation of the delivered x-ray treatment field. Quality assurance dosimetry for MRT must therefore overcome a significant challenge, as detectors require both a high dynamic range and a high spatial resolution to perform accurately. Approach. In this work, a series of radiation hard a-Si:H diodes, with different thicknesses and carrier selective contact configurations, have been characterised for x-ray dosimetry and real-time beam monitoring applications in extremely high flux beamlines utilised for MRT at the Australian Synchrotron. Results. These devices displayed superior radiation hardness under constant high dose-rate irradiations on the order of 6000 Gy s−1, with a variation in response of 10% over a delivered dose range of approximately 600 kGy. Dose linearity of each detector to x-rays with a peak energy of 117 keV is reported, with sensitivities ranging from (2.74 ± 0.02) nC/Gy to (4.96 ± 0.02) nC/Gy. For detectors with 0.8 μm thick active a-Si:H layer, their operation in an edge-on orientation allows for the reconstruction of micron-size beam profiles (microbeams). The microbeams, with a nominal full-width-half-max of 50 μm and a peak-to-peak separation of 400 μm, were reconstructed with extreme accuracy. The full-width-half-max was observed as 55 ± 1 μm. Evaluation of the peak-to-valley dose ratio and dose-rate dependence of the devices, as well as an x-ray induced charge (XBIC) map of a single pixel is also reported. Significance. These devices based on novel a-Si:H technology possess a unique combination of accurate dosimetric performance and radiation resistance, making them an ideal candidate for x-ray dosimetry in high dose-rate environments such as FLASH and MRT.
An AI-based universal phantom analysis method based on XML-SVG wireframes with novel functional object identifiers
Authors: Sakaamini Ahmad , Van Slyke Alexander , Partouche Julien , Wu Tianming , Wiersma Rodney D
Published: June 2023

Objective. Quality assurance (QA) testing must be performed at regular intervals to ensure that medical devices are operating within designed specifications. Numerous QA phantoms and software packages have been developed to facilitate measurements of machine performance. However, due to the hard-coded nature of geometric phantom definition in analysis software, users are typically limited to the use of a small subset of compatible QA phantoms. In this work, we present a novel AI-based universal Phantom (UniPhan) algorithm that is not phantom specific and can be easily adapted to any pre-existing image-based QA phantom. Approach. Extensible Markup Language Scalable Vector Graphics (XML-SVG) was modified to include several new tags describing the function of embedded phantom objects for use in QA analysis. Functional tags include contrast and density plugs, spatial linearity markers, resolution bars and edges, uniformity regions, and light-radiation field coincidence areas. Machine learning was used to develop an image classification model for automatic phantom type detection. After AI phantom identification, UniPhan imported the corresponding XML-SVG wireframe, registered it to the image taken during the QA process, performed analysis on the functional tags, and exported results for comparison to expected device specifications. Analysis results were compared to those generated by manual image analysis. Main results. XML-SVG wireframes were generated for several commercial phantoms including ones specific to CT, CBCT, kV planar imaging, and MV imaging. Several functional objects were developed and assigned to the graphical elements of the phantoms. The AI classification model was tested for training and validation accuracy and loss, along with phantom type prediction accuracy and speed. The results reported training and validation accuracies of 99%, phantom type prediction confidence scores of around 100%, and prediction speeds of around 0.1 s. Compared to manual image analysis, Uniphan results were consistent across all metrics including contrast-to-noise ratio, modulation-transfer function, HU accuracy, and uniformity. Significance. The UniPhan method can identify phantom type and use its corresponding wireframe to perform QA analysis. As these wireframes can be generated in a variety of ways this represents an accessible automated method of analyzing image-based QA phantoms that is flexible in scope and implementation.
Study of particle acceleration by Laguerre–Gaussian ultra intense laser plasma interactions
Authors: Culfa O , Sagir S , Satilmis I
Published: June 2023

In this work, simulations of multi-petawatt lasers in the range of ∼0.2 PW–∼100 PW with varying Laguerre–Gaussian (LG) azimuthal modes as well as linearly polarized (LP) and circularly polarized (CP) laser beams striking near critical density targets were studied by using three-dimensional particle in cell (PIC) codes. Particle acceleration mechanisms have a dependence on laser polarization and it affects the energy gained by the particles. It is known that laser pulses can be polarized helically by applying the LG distribution function to the fundamental Gaussian laser profile. In this study, differently polarized laser beams with varying powers were employed to study laser driven particle acceleration and compares accelerated charged particles’ energy spectra and angular distribution. It is seen that LG laser beams can accelerate higher energetic particles due to higher conversion efficiency compared to LP and CP laser beams. It is also seen that LG laser beams can collimate ions with a narrower spread compared to LP and CP beams. Furthermore, ions can have a smaller divergence angle with increasing azimuthal mode index when the laser is LG polarized. We also studied the energy deposition of these particles in a water cell obtained by the PIC codes for different laser parameters by using Geant4 Monte Carlo simulations which suggests that LG laser beam can be useful for the future hadron therapy applications.
Efficient modeling of electron kinetics under influence of externally applied electric field in magnetized weakly ionized plasma
Authors: Janalizadeh Reza , Pervez Zaid , Pasko Victor P
Published: June 2023

We present a theory based on the conventional two-term (i.e. Lorentzian) approximation to the exact solution of the Boltzmann equation in non-magnetized weakly ionized plasma to efficiently obtain the electron rate and transport coefficients in a magnetized plasma for an arbitrary magnitude and direction of applied electric field

E
⃗

and magnetic field

B
⃗

. The proposed transcendental method does not require the two-term solution of the Boltzmann equation in magnetized plasma, based on which the transport parameters vary as a function of the reduced electric field

E

/

N

, reduced electron cyclotron frequency

ω

c
e

/

N

, and angle

∠

E
⃗

,

B
⃗

between

E
⃗

and

B
⃗

vectors, where N is the density of neutrals. Comparisons between the coefficients derived from BOLSIG+’s solution (obtained via the two-term expansion when

B
⃗

≠
0

) and coefficients of the presented method are illustrated for air, a mixture of molecular hydrogen (H2) and helium (He) representing the giant gas planets of the Solar System, and pure carbon dioxide (CO2). The new approach may be used in the modeling of magnetized plasma encountered in the context of transient luminous events, e.g. sprite streamers in the atmosphere of Earth and Jupiter, in modeling the propagation of lightning’s electromagnetic pulses in Earth’s ionosphere, and in various laboratory and industrial applications of nonthermal plasmas.
Coupled electro-aeroelastic energy harvester model based on piezoelectric transducers, VIV-galloping interaction and nonlinear switching circuits
Authors: Priore Emiliano Del , Romano Giovanni Paolo , Lampani Luca
Published: June 2023

Miniaturization, multi-functionality, and low power consumption are key features in the development of electronic devices today. These characteristics open up the possibility for the development of small, self-powered systems. Piezoelectric materials have emerged as a promising solution due to their ability to convert mechanical energy into electrical energy from the surrounding environment, such as wind. In this research work, we investigate an aeroelastic piezoelectric energy harvester based on the interaction between vortex-induced vibrations and galloping. The device, a bimorph cantilevered beam with a square-section bluff body attached to its tip, produces mechanical oscillations that are extracted by various electrical circuits, including a nonlinear switching interface. A numerical model, implemented in a Simulink environment, is developed to solve the coupled electro-aeroelastic problem for each electrical interface. The results are compared to experimental data collected from wind tunnel tests conducted at various wind velocities and load resistances, and a satisfactory correlation is observed. The validated model is finally used to carry out a parametric analysis aimed at optimizing the performance of the harvester in a low wind speed range. This investigation could contribute to a better understanding of an aeroelastic harvesting system and potentially assist in the optimization of design parameters and electrical interfaces for specific applications.
Scaling superconducting quantum chip with highly integratable quantum building blocks
Authors: Cai Xiao , Zhou Boyi , Wu Yanfu , Li Shuming , Dong Yuqian , Feng Jiagui , Xiong Kanglin
Published: June 2023

Designing and fabricating large-scale superconducting quantum chips with increasing number of qubits is a pressing challenge for the quantum computing. Here, we propose a three-dimensional stacked chip architecture comprised with quantum building blocks. In which, two primary types of blocks are the qubit block and the coupling block. They are designed as functional parts that can be utilized within the same footprint across multiple levels of the chip stack in the vertical direction. Common technological problems, such as the sensitivity of capacitors and coupling strengths to fabrication parameters, and dielectric losses from interfaces, can be addressed at the intra-block or block level efficiently. Once a library of standard blocks is designed and verified, they can be selected and arranged into arrays on chips at the placing stage of the design flow for specific quantum applications. Such chip structure and design protocol will reduce the design difficulty, and promote the reuse of standard blocks, thus paving the way for chips for noisy intermediate-scale quantum computing and quantum error correction.
Unification of the four forces in the Spin(11,1) geometric algebra
Authors: Hamilton Andrew J S , McMaken Tyler
Published: June 2023

SO(10), or equivalently its covering group Spin(10), is a well-known promising grand unified group that contains the standard-model group. The spinors of the group Spin(N) of rotations in N spacetime dimensions are indexed by a bitcode with [N/2] bits. Fermions in Spin(10) are described by five bits yzrgb, consisting of two weak bits y and z, and three colour bits r, g, b. If a sixth bit t is added, necessary to accommodate a time dimension, then the enlarged Spin(11, 1) algebra contains the standard-model and Dirac algebras as commuting subalgebras, unifying the four forces. The minimal symmetry breaking chain that breaks Spin(11, 1) to the standard model is unique, proceeding via the Pati-Salam group. The minimal Higgs sector is similarly unique, consisting of the dimension 66 adjoint representation of Spin(11, 1); in effect, the scalar Higgs sector matches the vector gauge sector. Although the unified algebra is that of Spin(11, 1), the persistence of the electroweak Higgs field after grand symmetry breaking suggests that the gauge group before grand symmetry breaking is Spin(10, 1), not the full group Spin(11, 1). The running of coupling parameters predicts that the standard model should unify to the Pati-Salam group Spin(4)
w
× Spin(6)
c
at 1012 GeV, and thence to Spin(10, 1) at 1015 GeV. The grand Higgs field breaks t-symmetry, can drive cosmological inflation, and generates a large Majorana mass for the right-handed neutrino by flipping its t-bit. The electroweak Higgs field breaks y-symmetry, and generates masses for fermions by flipping their y-bit.
Twin-image-free compressive holography with autofocusing from single subsampled hologram
Authors: Zhang Cheng , Zhou Jiaxuan , Wu Feng , Wei Sui
Published: June 2023

Compressive-sensing-based twin-image-free approach is only capable to achieve twin-image-free reconstruction under 2D-2D imaging model with the full-sampling condition. In this paper, a compressive holography approach with autofocusing from a single-shot subsampled hologram is proposed. On the one hand, a subsampling mechanism is introduced to establish a subsampled compressive holographic imaging model; On the other hand, an eigenvalues-based autofocusing algorithm is combined with compressive-sensing to achieve autofocus reconstruction under subsampling condition in compressive holography. In addition, a multi-scale search algorithm is proposed to improve the accuracy of autofocus. Numerical experiments verify the feasibility of our proposed approach in terms of precisely autofocusing and twin-image-free reconstruction from single-shot subsampled holograms.
Improved diffractive-imaging based image encryption scheme in 3D space
Authors: Shan Mingguang , Xu Yanjun , Zhong Zhi , Liu Bin , Yu Lei , Xie Yongqiang , Liu Lei
Published: June 2023

In this paper, we present an improved diffractive-imaging-based image encryption scheme in 3D space. In this cryptosystem, the plaintext is divided into several sub-images by binary amplitude masks and then diffused into 3D space at different axial positions for encryption, which confuses the relation between the plaintext and the ciphertext to make the chosen-plaintext attack no longer work. For the decryption, we develop a modified iterative retrieval algorithm to retrieve a decrypted image with high quality. Additionally, this cryptosystem obtains higher security without increasing the amount of the ciphertext. Compared with previous diffractive-imaging-based image encryption schemes, the key space is enlarged so greatly that this cryptosystem can resist the brute force attack. Furthermore, this scheme can significantly reduce the computation and retrieve a decrypted image with high-quality.
Tunable nonlinear absorption and optical limiting behavior of NaBi(MoxW1−xO4)2 single crystals with ratio of Molybdenum/Tungsten
Authors: Pepe Yasemin , Yildiz Elif Akhuseyin , Isik Mehmet , Karatay Ahmet , Gasanly Nizami , Elmali Ayhan
Published: June 2023

The compositional effect of Mo/W ratio on linear, nonlinear absorption and optical limiting behavior of the NaBi(MoxW1−xO4)2 single crystals grown by Czochralski technique was investigated. X-ray diffraction patterns of the studied crystals presented well-defined peaks associated with the tetragonal crystalline structure. The nonlinear absorption performance and optical limiting threshold were determined using an open-aperture Z-scan technique. A theoretical model including one photon absorption (OPA), two photon absorption (TPA) and free carrier absorption was used to determine the nonlinear absorption parameters. All of the results showed that defect states, which strongly affect nonlinear absorption (NA) and optical limiting behaviors, can be tuned with the Mo/W ratio, enabling NaBi(MoxW1−xO4)2 single crystals to be used in desired optoelectronic applications. Linear optical absorption analysis revealed that bandgap energy and defect states can be tuned by changing the Mo/W ratio in the crystal structure. The obtained results showed that all the studied crystals had NA behavior and the nonlinear absorption coefficient decreased with increasing Mo/W ratio. Sequential TPA is the main NA mechanism for these crystals due to the fact that the incident light energy is lower than the bandgap energies and the existence of the real intermediate state around 2.32 eV.
Band gap characteristics of multi-functional lattice metamaterials with adjustable thermal expansion and Poisson's ratio
Authors: Liu Hongliang , Jiang Yihuang , Xu Weikai , Wang Wei , Yu Xiaoming
Published: June 2023

The current development of science and technology has put increased demands on the versatility of metamaterials. In this paper, the band gap characteristics of a lattice metamaterial that can simultaneously modulate thermal expansion and Poisson’s ratio are studied, the dispersion characteristics of elastic waves propagating in periodic lattice metamaterials are analyzed, and the effects of different structures and parameters on the band gap are discussed. The results indicate that the configuration has excellent band gap properties while satisfying the tunable coefficient thermal expansion (CTE)and Poisson’s ratio functions. Through reasonable material selection and shape design, it is expected to achieve a multi-objective win-win for specific thermal expansion properties, Poisson’s ratio, and band gap design, resulting in better tunability and versatility of the metamaterial.
Sensing strategy based on random slot semiconductor laser
Authors: Jia Xiaoqin , Wang Yufei , Liu Guangqiang , Zhou Xuyan , Zhang Jianxin , Dong Fengxin , Gong Kai , Zhang Run
Published: June 2023

A photonic sensor based on a random slot surface-emitting semiconductor laser is theoretically demonstrated by utilizing multi-order diffraction. The results show that the variation of far-field local speckles at single wavelength lasing can be utilized to confirm the refractive index of the substances and the flow velocity of erythrocytes in capillaries. The similarity of the intensity contrast is the other protocol to measure the flow velocity of erythrocytes. Additionally, the similarity of the spectral contrast at multiple wavelengths lasing can be used to determine the concentration of erythrocytes in capillaries. The random slot semiconductor laser may provide a new and flexible platform for versatile active sensing.
Estimating cross-field particle transport at the outer midplane of TCV by tracking filaments with machine learning
Authors: Han W. , Offeddu N. , Golfinopoulos T. , Theiler C. , Terry J.L. , Wüthrich C. , Galassi D. , Colandrea C. , Marmar E.S.
Published: June 2023

Cross-field transport of particles in the boundary region of magnetically confined fusion plasmas is dominated by turbulence. Blobs, intermittent turbulent structures with large amplitude and a filamentary shape appearing in the scrape-off layer (SOL), are known from theoretical and experimental studies to be the main contributor to the cross-field particle transport. The dynamics of blobs differs depending on various plasma conditions, including triangularity (δ). In this work, we analyze triangularity dependence of the cross-field particle transport at the outer midplane of plasmas with

δ
=
+
0.38

, +0.15, −0.14, and −0.26 on the Tokamak à Configuration Variable, using our novel machine learning (ML) blob-tracking approach applied to gas puff imaging data. The cross-field particle flux determined in this way is of the same order as the overall transport inferred from KN1D, GBS, and SOLPS-ITER simulations, suggesting that the blobs identified by the ML blob-tracking account for most of the cross-field particle transport in the SOL. Also, the ML blob-tracking and KN1D show a decrease in the cross-field particle transport as δ becomes more negative. The blob-by-blob analysis of the result from the tracking reveals that the decrease of cross-field particle transport with decreasing δ is accompanied by a decrease in the number of blobs in a fixed time, which tend to have larger area and lower radial speed. Also, the blobs in these plasmas are in the connected sheath regime, and show a velocity scaling consistent with the two-region model.
NEXT-White results and roadmap towards a ton-scale detector
Authors: Novella Pau
Published: June 2023

The goal of the NEXT collaboration is the sensitive search of the neutrinoless double beta decay of 136Xe at the Laboratorio Subterráneo de Canfranc. A first large-scale prototype of a high-pressure gas-Xenon electroluminescent TPC, NEXT-White, was operated from 2016 to 2021. This 4–kg radiopure detector has proven the outstanding performance of the NEXT technology in terms of the energy resolution (<1% FWHM at 2.6 MeV) and the topology-based background rejection. After measuring the relevant backgrounds and their spatial origin, the NEXT-White data collected with 136Xe-enriched and 136Xe-depleted gas have been used to perform a measurement of the two-neutrino mode of the double beta decay. A novel technique based on a direct background subtraction yields a half-life of

2.34

−
0.46

+
0.80

(
stat
)

−
0.17

+
0.30

(sys)
×

10

21

yr

. This result is consistent with the half-life derived from a background-model-dependent approach. Scaling the technological solutions of NEXT-White, the NEXT-100 detector is being constructed during 2022 and will start the physics data taking in 2023. Holding 100 kg of 136Xe and with a background index below 5×10−4 counts/keV/kg/year, NEXT-100 will perform the first competitive search for the neutrinoless double beta decay within the NEXT roadmap. After 3 years of data taking, a sensitivity to the half-life of 6×1025 yr at 90% C.L. will be achieved. The design for a future ton-scale detector, NEXT-HD, is being carried out in paralel. Operating with low-difussion gas mixtures and a reduced background budget, NEXT-HD will reach sensitivities above 1027 yr. A promising R&D line aims at eventually equiping the NEXT techonlogy with 136Ba-tagging capabilities, opening the doors for a truly background-free experiment.