bluuebunny/crossref_metadata_2025 huggingface dataset:
New hybrid maximum power point tracking methods for fuel cell using artificial intelligent
Authors: Safarishaal Masoud , Sarvi Mohammad
Published: April 2023

An efficient way to raise the proton exchange membrane fuel cell’s (PEMFC’s) power generation efficiency and power supply quality is to use maximum power point tracking (MPPT). Conventional MPPT approaches often have difficulty producing an effective control effect due to the PEMFC’s inherent nonlinear characteristics. Another challenge for systems that track maximum power points is dealing with fast changes in operational conditions that affect FC’s maximum power point (MPP). The main contribution of this study is the introduction of two artificial intelligence-based MPP control approaches for fuel cells operating under rapidly changing operating conditions. These methods are based on imperialist competitive algorithm-trained neural networks and adaptive neuro-fuzzy inference systems (ANFIS) (ICA NN). The proposed approaches determine the fuel cell voltage that corresponds to the maximum power point. Following that, a fuzzy logic controller is used to modify the duty cycle of a DC/DC boost converter for FC MPP tracking. The MATLAB environment is used to run simulations. The results of the proposed method are compared with those of the conventional fuzzy method. The results demonstrate that the suggested solutions function excellently in both normal operating conditions and quickly varying operating conditions. On the other hand, the suggested approaches can quickly locate and monitor the MPP of FC. Additionally, the suggested techniques increase the FC system’s efficiency by absorbing more power.
X-ray induced electron and ion fragmentation dynamics in IBr
Authors: Ho Phay J. , Ray Dipanwita , Lehmann C. Stefan , Fouda Adam E. A. , Dunford Robert W. , Kanter Elliot P. , Doumy Gilles , Young Linda , Walko Donald A. , Zheng Xuechen , Cheng Lan , Southworth Stephen H.
Published: April 2023

Characterization of the inner-shell decay processes in molecules containing heavy elements is key to understanding x-ray damage of molecules and materials and for medical applications with Auger-electron-emitting radionuclides. The 1s hole states of heavy atoms can be produced by absorption of tunable x rays and the resulting vacancy decays characterized by recording emitted photons, electrons, and ions. The 1s hole states in heavy elements have large x-ray fluorescence yields that transfer the hole to intermediate electron shells that then decay by sequential Auger-electron transitions that increase the ion’s charge state until the final state is reached. In molecules, the charge is spread across the atomic sites, resulting in dissociation to energetic atomic ions. We have used x-ray/ion coincidence spectroscopy to measure charge states and energies of Iq+ and Brq′+ atomic ions following 1s ionization at the I and Br K-edges of IBr. We present the charge states and kinetic energies of the two correlated fragment ions associated with core-excited states produced during the various steps of the cascades. To understand the dynamics leading to the ion data, we develop a computational model that combines Monte-Carlo/Molecular-Dynamics (MC/MD) simulations with a classical over-the-barrier model to track inner-shell cascades and redistribution of electrons in valence orbitals and nuclear motion of fragments.
The fatigue effects in red emissive CdSe based QLED operated around turn-on voltage
Authors: Zhang Xin , Bao Hui , Chen Cuili , Wu Xian-gang , Li Menglin , Ji Wenyu , Wang Shuangpeng , Zhong Haizheng
Published: April 2023

The operational stability is a current bottleneck facing the quantum dot light-emitting diodes (QLEDs). In particular, the device working around turn-on voltage suffers from unbalanced charge injection and heavy power loss. Here, we investigate the operational stability of red emissive CdSe QLEDs operated at different applied voltages. Compared to the rising luminance at higher voltages, the device luminance quickly decreases when loaded around the turn-on voltage, but recovers after unloading or slight heat treatment, which is termed fatigue effects of operational QLED. The electroluminescence and photoluminescence spectra before and after a period of operation at low voltages show that the abrupt decrease in device luminance derives from the reduction of quantum yield in quantum dots. Combined with transient photoluminescence and electroluminescence measurements, as well as equivalent circuit model analysis, the electron accumulation in quantum dots mainly accounts for the observed fatigue effects of a QLED during the operation around turn-on voltage. The underlying mechanisms at the low-voltage working regime will be very helpful for the industrialization of QLED.
Dynamics of electrified liquid metal surface using shallow water model
Authors: Hara Kentaro , Shneider Mikhail N.
Published: April 2023

A shallow water model that incorporates surface tension and electric field effects is developed to investigate the dynamics of an electrified liquid surface. The computational model is verified against the Zakharov–Kuznetsov equation and is applied to study the growth and damping of the electrified liquid surface. A linear wave analysis is performed under a shallow water theory assuming an analytic solution of the electric field, similar to the Tonks–Frenkel instability. The electrified liquid surface grows or dampens based on the balance of the electric field, surface tension, and gravitational forces. The numerical results obtained from the electrified shallow water solver are in good agreement with the theoretical analysis.
Lateral p-type GaN Schottky barrier diode with annealed Mg ohmic contact layer demonstrating ideal current–voltage characteristic
Authors: Lu Shun , Deki Manato , Kumabe Takeru , Wang Jia , Ohnishi Kazuki , Watanabe Hirotaka , Nitta Shugo , Honda Yoshio , Amano Hiroshi
Published: April 2023

We have demonstrated the fabrication process for a lateral p-type Schottky barrier diode (SBD) with the annealed Mg ohmic contact layer on a MOVPE-grown p-GaN wafer and measured the electrical characteristic of the diode. Because of the selective-area ohmic contact, the interface between the Schottky electrode and p-type GaN is well protected from any damage introduced by dry-etching or regrowth. The ideality factor of the forward current–voltage characteristic is as low as 1.09 at room temperature and an on–off ratio above 109 is also achieved. Various metals are deposited as the Schottky electrode and the work function dependence of the Schottky barrier height is confirmed with a pinning factor of 0.58. The temperature dependence of the current–voltage characteristic indicates that the GaN p-type SBD still fits the thermionic emission mode at 600 K with an ideality factor of 1.1. The reverse current of the p-SBD is also studied with the Poole–Frenkel emission model, and the trap energy level in the p-GaN is confirmed.
An improved asymptotic expansion method for fluid flow and convective heat transfer in cone-and-disk geometries with rotating cone
Authors: Shevchuk Igor V.
Published: April 2023

In this paper, an improved asymptotic expansion method has been developed to simulate fluid flow and convective heat transfer in a conical gap at small conicity angles up to 4°. Unlike previous works, the improved asymptotic expansion method was applied to the self-similar system of Navier–Stokes equations for small conicity angles. The characteristic Reynolds number varied in the range from 0.001 to 2.0. A detailed validation of the improved asymptotic expansion method compared to the self-similar solution performed for the case of cone rotation with a fixed disk demonstrated its significant advantages compared to previously known asymptotic expansion methods. For the first time, novel approximate analytical solutions were obtained for the tangential and axial velocity components, the swirling angle of the flow, tangential shear stresses on the surface of a fixed disk, as well as static pressure distribution varying in the gap height, which perfectly coincide with the self-similar solution. The accuracy of the improved asymptotic expansion method in the numerical calculation of the Nusselt number in the range of Prandtl numbers from Pr = 0.71 to Pr = 10 significantly exceeds the accuracy of the previously known asymptotic expansion methods. This enables expanding the range of Reynolds and Prandtl numbers, for which the improved asymptotic expansion method has approximately the same accuracy as the self-similar solution. The fact is confirmed that the account for the radial thermal conductivity in the energy equation in the case of small conicity angles up to 4° leads to insignificant deviations of the Nusselt number (maximum 1.5%).
Aperture-induced spectral effects in stimulated Brillouin scattering microscopy
Authors: Shaashoua Roni , Bilenca Alberto
Published: April 2023

Stimulated Brillouin scattering (SBS) microscopy is emerging as a promising approach for mechanical imaging in biological settings. It is based on a spectroscopic backscattering SBS setup, but with scanning of the sample and using higher apertures of the excitation and collection optics for adequate spatial sampling. Here, we provide direct experimental measurements and theoretical predictions of the aperture-induced spectral effects of SBS microscopy in water—a key constituent of biological systems. It is shown that with increasing numerical aperture (NA), the Brillouin frequency shift and peak gain decrease, while the Brillouin linewidth broadens asymmetrically with the commencing of an extended tail in the low frequency region for NA > ∼0.5. Further, significant distortions of the Brillouin spectral line shape are predicted for NAs close to 1, affecting the ability to retrieve spectral parameters of the Brillouin medium precisely and accurately.
Two-photon electromagnetic induction imaging with an atomic magnetometer
Authors: Maddox Benjamin , Renzoni Ferruccio
Published: April 2023

Electromagnetic induction imaging (EMI) is a contactless, nondestructive evaluation technique based on sensing the response of a target to oscillating magnetic fields as they penetrate into materials. Leveraging the enhanced performance of radio frequency atomic magnetometers (RF-AMs) at low frequencies can enable highly sensitive through-barrier EMI measurements, which, for example, can reveal concealed weaponry or inspect subsurface material defects. However, deriving this advantage requires precise control of a well-defined, low bias magnetic field with respect to the background magnetic field texture, which presents a cumbersome challenge to stabilize in real-world unshielded scenarios. Here, we implement a two-photon RF-AM scheme in a portable setup to bypass the requirement of a low bias field and achieve stable, repeatable resonances in the sub-kHz regime. The improved accessibility to lower primary field frequencies offer greater skin-depth in target materials and facilitates an enhancement of a factor of 8 in skin penetration with this portable system, detecting features behind an Al shield of 3.2 mm. The scheme also reduces the need of large compensation coils to stabilize the bias field, facilitating the implementation of compact devices.
eIF2Bδ blocks the integrated stress response and maintains eIF2B activity and cancer metastasis by overexpression in breast cancer stem cells
Authors: Gupta Malavika , Walters Beth A. , Katsara Olga , Granados Blanco Karol , Geter Phillip A. , Schneider Robert J.
Published: April 2023

Breast cancer (BC) metastasis involves cancer stem cells (CSCs) and their regulation by micro-RNAs (miRs), but miR targeting of the translation machinery in CSCs is poorly explored. We therefore screened miR expression levels in a range of BC cell lines, comparing non-CSCs to CSCs, and focused on miRs that target translation and protein synthesis factors. We describe a unique translation regulatory axis enacted by reduced expression of miR-183 in breast CSCs, which we show targets the eIF2Bδ subunit of guanine nucleotide exchange factor eIF2B, a regulator of protein synthesis and the integrated stress response (ISR) pathway. We report that reduced expression of miR-183 greatly increases eIF2Bδ protein levels, preventing strong induction of the ISR and eIF2α phosphorylation, by preferential interaction with P-eIF2α. eIF2Bδ overexpression is essential for BC cell invasion, metastasis, maintenance of metastases, and breast CSC expansion in animal models. Increased expression of eIF2Bδ, a site of action of the drug ISRIB that also prevents ISR signaling, is essential for breast CSC maintenance and metastatic capacity.
Optimal inference of molecular interaction dynamics in FRET microscopy
Authors: Kamino Keita , Kadakia Nirag , Avgidis Fotios , Liu Zhe-Xuan , Aoki Kazuhiro , Shimizu Thomas S. , Emonet Thierry
Published: April 2023

Intensity-based time-lapse fluorescence resonance energy transfer (FRET) microscopy has been a major tool for investigating cellular processes, converting otherwise unobservable molecular interactions into fluorescence time series. However, inferring the molecular interaction dynamics from the observables remains a challenging inverse problem, particularly when measurement noise and photobleaching are nonnegligible—a common situation in single-cell analysis. The conventional approach is to process the time-series data algebraically, but such methods inevitably accumulate the measurement noise and reduce the signal-to-noise ratio (SNR), limiting the scope of FRET microscopy. Here, we introduce an alternative probabilistic approach, B-FRET, generally applicable to standard 3-cube FRET-imaging data. Based on Bayesian filtering theory, B-FRET implements a statistically optimal way to infer molecular interactions and thus drastically improves the SNR. We validate B-FRET using simulated data and then apply it to real data, including the notoriously noisy in vivo FRET time series from individual bacterial cells to reveal signaling dynamics otherwise hidden in the noise.
FOXO-mediated repression of Dicer1 regulates metabolism, stress resistance, and longevity in
Drosophila
Authors: Sánchez Juan A. , Ingaramo María C. , Gervé María P. , Thomas Maria G. , Boccaccio Graciela L. , Dekanty Andrés
Published: April 2023

The adipose tissue plays a crucial role in metabolism and physiology, affecting animal lifespan and susceptibility to disease. In this study, we present evidence that adipose Dicer1 (Dcr-1), a conserved type III endoribonuclease involved in miRNA processing, plays a crucial role in the regulation of metabolism, stress resistance, and longevity. Our results indicate that the expression of Dcr-1 in murine 3T3L1 adipocytes is responsive to changes in nutrient levels and is subject to tight regulation in the
Drosophila
fat body, analogous to human adipose and hepatic tissues, under various stress and physiological conditions such as starvation, oxidative stress, and aging. The specific depletion of Dcr-1 in the
Drosophila
fat body leads to changes in lipid metabolism, enhanced resistance to oxidative and nutritional stress, and is associated with a significant increase in lifespan. Moreover, we provide mechanistic evidence showing that the JNK-activated transcription factor FOXO binds to conserved DNA-binding sites in the
dcr-1
promoter, directly repressing its expression in response to nutrient deprivation. Our findings emphasize the importance of FOXO in controlling nutrient responses in the fat body by suppressing Dcr-1 expression. This mechanism coupling nutrient status with miRNA biogenesis represents a novel and previously unappreciated function of the JNK-FOXO axis in physiological responses at the organismal level.
Intransitivity as a dynamic assembly engine of competitive communities
Authors: Vandermeer John , Perfecto Ivette
Published: April 2023

Historically, those ecological communities thought to be dominated by competitive interactions among their component species have been assumed to exhibit transitive competition, that is, a hierarchy of competitive strength from most dominant to most submissive. A surge of recent literature takes issue with this assumption and notes that some species in some communities are intransitive, where a rock/scissors/paper arrangement characterizes some components of some communities. We here propose a merging of these two ideas, wherein an intransitive subgroup of species connects with a distinct subcomponent that is organized hierarchically, such that the expected eventual takeover by the dominant competitor in the hierarchy is thwarted, and the entire community can be sustained. This means that the combination of transitive and intransitive structures can maintain many species even when competition is strong. Here, we develop this theoretical framework using a simple variant on the Lotka–Volterra competition equations to illustrate the process. We also present data for the ant community in a coffee agroecosystem in Puerto Rico, that appears to be organized in this way. A detailed study on one typical coffee farm illustrates an intransitive loop of three species that seems to maintain a distinct competitive community of at least 13 additional species.
ANN for design and fabrication of ENi-P-nano TiO2 coatings on AH36 steel
Authors: Anthoni Sagaya Selvan R. , Thakur Dinesh G. , Salunkhe Sachin
Published: April 2023

Designing optimal ENi-P-nano TiO2 with higher surface hardness is time-consuming and expensive. Thus, this study is aims to develop the optimal optimiser-based ANN model to forcast Vickers hardness for newer process parametric combinations and find the ideal  combination before manufacture. Consequently, three ANN model were devised using ADAM, AdaMax, and RMSprop optimisers with identical data set for training and testing. mean Squared Error (MSE) and R2 values were used to compare and assess their performance. Rectified Linear Unit (ReLU) is used to provide nonlinearity to  the neural network's output since the activation function affects ANN model performance. The study also highlights hyperparameter setting's  impact on optimiser performance. The ADAM-based ANN model was determined as optimal design through comparing the predicted and experimental Vickers hardness for the unknown combinations using Taguchi DOE. In addition, FESEM and XRD micrographs confirmed the optimal coating's morphology and phases. This study results shown   the compatibility of utilising ANN-based prediction models for ENi-P-nanoTiO2 coating design and prediction, however future research much incoporates more process parameters and their level ranges.
Laser shock peening rounds influencing microstructural and mechanical properties of 300M steel
Authors: Xiong Yi , Zhou Tian , Chen Zheng-ge , Wu Yong-li , Zha Xiao-qin , Li Yong , Wang Shu-bo , Singh Harishchandra , Huttula Marko , Cao Wei
Published: April 2023

Laser shock peeing (LSP) was introduced to produce surface gradient structures on 300M steel to improve its performance, service life and related workpiece safety. The influences of LSP rounds on microstructural and mechanical properties were investigated to optimise the LSP processing. Smoother surface, surface nanocystallization, and gradient structure, hardness, compressive residue stress was observed LSP. Strength and plasticity of 300M steel improved significantly due to the surface changes induced by one round of LSP. However, excessive LSP rounds tend to deteriorate the surface roughness and mechanical properties despite increased surface nanocrystallization, hardening zone depth and compressive residual stress.
CCQM-K68.2019, nitrous oxide (N2O) in air, ambient level, final report
Authors: Viallon J , Choteau T , Flores E , Idrees F , Moussay P , Wielgosz R I , Lim J S , Lee Jeongsoon , Lee Jinbok , Moon Dongmin , Wijk J I T van , Persijn S , Veen A M H van der , Efremova O V , Konopelko L , Kustikov Y , Kolobova A , Klimov A , Bi Z , Cecelski C , Carney J , Toman B , Possolo A , Hall B , Brewer P , Worton D , Saarnio K , Aaltonen H , Tshilongo J , Mogale D Mphara , Mphaphuli G , Marebane P Mohweledi
Published: April 2023

Main text

The key comparison CCQM-K68.2019 was aimed at evaluating the level of comparability of laboratories' capabilities for preparing nitrous oxide in air primary reference mixtures at ambient amount fractions, in the range 320 nmol mol−1 to 350 nmol mol−1.

The comparison was coordinated by the BIPM and the KRISS. It consisted in the simultaneous comparison of a suite of 2n primary gas standards, two standards to be prepared by each of the n participating laboratories. Two independent analytical methods were used by the BIPM to analyse the amount fraction of N2O in air, namely Gas Chromatography with an Electron Capture Detector (GC−ECD) and Quantum Cascade Laser Absorption Spectroscopy (QCLAS).

Since the circulation of the Draft A report in April 2021, four meetings took place with participants to discuss the mathematical treatment of the comparisons results, and several models were proposed. The model chosen by participants is the Bayesian Errors−In−Variables regression with shades of dark uncertainty. In this final report, the Key Comparison Reference Values were obtained with this model, with calculations performed by B Toman and A Possolo.

The key comparison CCQM-K68.2019 is considered to present an analytical challenge and therefore classified as Track C comparison in the CCQM nomenclature.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Inverse problems of damped wave equations with Robin boundary conditions: an application to blood perfusion
Authors: Fang Yan-Long , Lesnic Daniel , Alosaimi Moataz
Published: April 2023

Knowledge of the properties of biological tissues is essential in monitoring any abnormalities that may be forming and have a major impact on organs malfunctioning. Therefore, these disorders must be detected and treated early to save lives and improve the general health. Within the framework of thermal therapies, e.g. hyperthermia or cryoablation, the knowledge of the tissue temperature and of the blood perfusion rate are of utmost importance. Therefore, motivated by such a significant biomedical application, this paper investigates, for the first time, the uniqueness and stable reconstruction of the space-dependent (heterogeneous) perfusion coefficient in the thermal-wave hyperbolic model of bio-heat transfer from Cauchy boundary data using the powerful technique of Carleman estimates. Additional novelties consist in the consideration of Robin boundary conditions, as well as developing a mathematical analysis that leads to stronger stability estimates valid over a shorter time interval than usually reported in the literature of coefficient identification problems for hyperbolic partial differential equations. Numerically, the inverse coefficient problem is recast as a nonlinear least-squares minimization that is solved using the conjugate gradient method (CGM). Both exact and noisy data are inverted. To achieve stability, the CGM is stopped according to the discrepancy principle. Numerical results for a physical example are presented and discussed, showing the convergence, accuracy and stability of the inversion procedure.
Evaluation of the transdermal permeation and anticancer effects of plasma-activated Aristoflex AVC hydrogel in an artificial skin model
Authors: Jing Xixi , Wu Tong , Liu Dingxin , Zhang Hao , Xu Shengduo , Zhang Jishen , Wang Zifeng , Zhou Renwu , Xu Dehui , Xu Han , Wang Xiaohua , Rong Mingzhe , Zhao Yan
Published: April 2023

Plasma-activated hydrogels have promising application prospects in the field of transdermal penetration therapy, such as subcutaneous tumours, due to their long-lasting, slow-release properties and ability to be easily applied to skin. In this study, surface air plasma was used to prepare plasma-activated Aristoflex AVC hydrogel (PAH) and plasma-activated water (PAW) by irradiation. The characteristics of PAH and PAW were further studied in terms of reactive oxygen species (ROS) storage, transdermal permeation, and in vitro anticancer effects in an artificial skin model. The experimental results showed that PAH had a prolonged storage time of ROS and more transdermal permeation of ROS through artificial skin in Franz diffusion cell after 30 h compared to PAW, which means PAH could be superior to PAW for long-term applications on the skin surface. The in vitro anticancer effects of PAH in an artificial skin model were also better than those of PAW, reducing the viability of A375 cells without causing damage to HaCaT cells. Our study shows that PAH is superior to PAW in body-surface coating applications and can be used for subcutaneous anticancer applications.
A novel non-contact, magnetic-based stress inspection technology and its application to stress concentration zone diagnosis in pipelines
Authors: He Tengjiao , Liao Kexi , Leng Jihui , He Guoxi , Zhu Hongdong , Zhao Shuai
Published: April 2023

During their construction and long-term operation, stress concentration zones (SCZs) will inevitably occur in buried pipelines. This may cause pipe leakage or fracture failures. Therefore, it is essential to inspect and identify the precise position and stress damage degree of SCZs. Non-contact pipeline magnetic-based stress inspection (PMSI) is an important topic in the field of oil and gas pipeline stress inspection. In order to determine the response of a non-contact magnetic gradient signal to the stress damage of SCZs, we establish a PMSI model to analyze the three-dimensional magnetic signals of SCZs. The effects of changes to the axial stress value, the stress concentration length, the detection height and the gradiometer jitter are also studied. In addition, the PMSI is carried out on a 10.3 km liquefied natural gas buried pipeline, which is validated by the excavation inspection results. The results indicate that the x component of the magnetic gradient signal, Gx
, shows sinusoidal fluctuation near a SCZ, and the y and z components, Gy
and Gz,
each reach a peak value. The G
max value, the maximal magnetic gradient modulus, increases with the severity and length of the SCZs. As a result, two level-II SCZs and two level-III SCZs are identified.
Real-time measurement of minimum cross-sectional area and radius of curvature of miniature plate specimens using a high-speed laser profiler for calculating true stress-true strain curves
Authors: Kato Taichiro , Ruan Xiaoyong , Nozawa Takashi
Published: April 2023

True stress-true strain curves are fundamental for designing and analyzing structures such as fusion reactors. These curves are typically obtained by conducting tensile tests on round bar specimens. However, due to material dimension limitations, plate specimens are sometimes used instead of round bar specimens. Obtaining true stress-true strain curves experimentally from plate specimens can be challenging. To address this challenge, this study aims to obtain true stress-true strain curves of miniature plate specimens using both analytical and experimental methods. The analytical method involved inverse finite element method (FEM), while the experimental method utilized real-time measurement of the minimum cross-sectional area and radius of curvature of a miniature plate specimen with a high-speed laser profiler. Comparing the true stresses obtained from the analytical and experimental methods, we found that the difference was typically within 5%. These findings suggest that inverse FEM and laser profilometry are effective methods for determining the true stress-true strain of miniature plate specimens.
Intelligent indoor localization based on CSI via radio images and deep learning
Authors: Zhang Yunwei , Fan Mochan , Xu Chendong
Published: April 2023

The universality of intelligent indoor localization based on WIFI has increasingly emerged as a multifold challenge. However, in practical applications, its indoor localization accuracy is limited by noises, diffractions, and multipath effects. To overcome these drawbacks, we design a new intelligent indoor localization system based on channel state information (CSI) of the wireless signal from multiple-input multiple-output (MIMO): IILC. In IILC, the initial amplitude information is first processed in the measured CSI data, which can effectively suppress the impact from noise and other interferences. Next, we devised a method to construct radio images. It can fully use space-frequency and time-frequency information from CSI-MIMO to obtain more location information. Next, we design a new deep learning network to determine the optimal effectiveness of radio image classification. Subsequently, a mixed norm is proposed to impose sparsity penalty and overfit constraint on the loss function, making the valuable feature units active and the others inactive. The experimental results verify that the IILC system exhibits excellent performance. The overall localization accuracy of the IILC in the office scene can reach 97.10%, and the probability of localization error within 1.2 m is 86.21%.
Measurement of bearing reaction force by distributed strain variation
Authors: Wang Rui , Kong Chengcheng , Zhang Yudong , Yu Wennian , Huang Wenbin , Wang Liming
Published: April 2023

Bearing is a crucial transmission component of aero-engines under high-speed and heavy-load conditions. To design a roller bearing with high loading capacity and reliability, it is essential to focus on the relationship between the external load state (reaction force) and the internal load distribution (load distribution). Therefore, a measurement method for bearing reaction force using load distribution and radial basis function neural network is presented in this study. Unlike conventional static reaction force measurement methods, both the direction and magnitude of the reaction force are considered in the proposed method without modifications to bearing. First, an experimental system is designed to investigate the load distribution in a roller bearing under different reaction forces using strain variation measurements. Then, a finite element analysis is conducted, and simulation results of the strain variations at three interested points match well with the experimental measurements. Finally, a radial basis function neural network with strong nonlinear fitting ability is applied to construct the mapping relationship between strain variation and reaction force. The results demonstrate that the proposed method can predict the reaction force with high accuracy based on the strain variation at three measuring points.
Calculating the Sun radius using a projection tube, a smartphone and a geometry software
Authors: Arias Maritza , Caerols Hugo , Asenjo Felipe A
Published: April 2023

We revisit the known experiment of using the solar projection along a tube in order to calculate the Sun’s radius. However, we propose several features that greatly improve the precision in the measurements. We discuss how the shape of the performation hole affect the results, and what is the best way to construct it. We also discuss how the examination of the measurements can be performed through photographs taken with smartphones, and their analysis using different free softwares. We also propose how a general theory can be formulated to determine the radius of the Sun with only measurements made with this kind of experiment, without any external parameter to the apparatus. Its usefulness and applicability is also considered. With all these additions to this known experience, this work is focused in taking advantage of the strength of smartphones and software technologies to get powerful and precise astronomical results as an educational tool.
2D medical image synthesis using transformer-based denoising diffusion probabilistic model
Authors: Pan Shaoyan , Wang Tonghe , Qiu Richard L J , Axente Marian , Chang Chih-Wei , Peng Junbo , Patel Ashish B , Shelton Joseph , Patel Sagar A , Roper Justin , Yang Xiaofeng
Published: April 2023

Objective. Artificial intelligence (AI) methods have gained popularity in medical imaging research. The size and scope of the training image datasets needed for successful AI model deployment does not always have the desired scale. In this paper, we introduce a medical image synthesis framework aimed at addressing the challenge of limited training datasets for AI models. Approach. The proposed 2D image synthesis framework is based on a diffusion model using a Swin-transformer-based network. This model consists of a forward Gaussian noise process and a reverse process using the transformer-based diffusion model for denoising. Training data includes four image datasets: chest x-rays, heart MRI, pelvic CT, and abdomen CT. We evaluated the authenticity, quality, and diversity of the synthetic images using visual Turing assessments conducted by three medical physicists, and four quantitative evaluations: the Inception score (IS), Fréchet Inception Distance score (FID), feature similarity and diversity score (DS, indicating diversity similarity) between the synthetic and true images. To leverage the framework value for training AI models, we conducted COVID-19 classification tasks using real images, synthetic images, and mixtures of both images. Main results. Visual Turing assessments showed an average accuracy of 0.64 (accuracy converging to

50
%

indicates a better realistic visual appearance of the synthetic images), sensitivity of 0.79, and specificity of 0.50. Average quantitative accuracy obtained from all datasets were IS = 2.28, FID = 37.27, FDS = 0.20, and DS = 0.86. For the COVID-19 classification task, the baseline network obtained an accuracy of 0.88 using a pure real dataset, 0.89 using a pure synthetic dataset, and 0.93 using a dataset mixed of real and synthetic data. Significance. A image synthesis framework was demonstrated for medical image synthesis, which can generate high-quality medical images of different imaging modalities with the purpose of supplementing existing training sets for AI model deployment. This method has potential applications in many data-driven medical imaging research.
Assessment of relevant pinch magnitudes of plasma focus devices based on non-uniform internal distributions of density and temperature
Authors: Giovachini R , Barbaglia M , Abraham-Ekeroth R M , Clausse A
Published: April 2023

A novel model of the dense z-pinch of a plasma focus (PF) discharge is presented, assuming Gaussian radial distributions of density and temperature inside the pinch. The model is used to assess the temperature, size and lifetime of the focus conflating with available experimental data gathered from discharges in Deuterium performed in the PF PACO with three cathode configurations. The resulting estimations were mean pinch temperatures between 1 and 12 keV, and pinch durations between 10 and 120 ns, each magnitude decreasing and increasing with the filling pressure, respectively. Moreover, the relation found between the mean pinch radius and temperature,

⟨

r

p

⟩

and

⟨

T

p

⟩

, is consistent with an adiabatic compression given by

⟨

r

p

⟩

⟨

T

p

⟩

3

/

4

≅
1.2
−
1.6

mm keV3/4. The estimated width of the Gaussian profile is in agreement with spectroscopic images obtained in another small device.
Impact of pyrolysis temperature on physicochemical properties of carbon nitride photocatalyst
Authors: Kamble Gopichand , Ganai Abdul Majeed , Lakshmi Devatade Vijaya , Rao N Nageswara , Rajarikam Nagaraju , Rao Pallapothula Venkateswar
Published: April 2023

Polymeric carbon nitride (CN) materials are exigent in a wide variety of photocatalytic applications. Although CN has unique optoelectronic properties, poor surface area and limited light absorption are major bottlenecks in the exploration of CN photocatalysts. In this study, we present a facile template or patterning agent free route to high surface area CN scaffolds by varying the thermal pyrolysis temperature. As the pyrolysis temperature increased from 550 °C to 700 °C, a drastic improvement in visible light absorbance as well as surface area was noted. The photoactivity of the prepared material evaluated for visible-light induced dye degradation demonstrated that the pyrolysis temperature of CN governs its photocatalytic performance. A pyrolysis temperature of 680 °C was found to be sub-optimal to realize better optoelectronic properties. As prepared, high surface area materials were also used for low-pressure CO2 uptake studies, which again supplemented the excellent results for high temperature processed CN. Besides, the photoluminescence and electrochemical analysis indicate that high temperature pyrolysis significantly reduces charge carrier recombination of CN catalysts.
Electrochemical etching modes of 4H-SiC in KOH solutions
Authors: Yang Shangyu , Zhao Siqi , Chen Junhong , Li Yunkai , Yan Guoguo , Guan Min , Zhang Yang , Sun Guosheng , Zeng Yiping , Liu Xingfang
Published: April 2023

Electrochemical etching is a promising wet etching technology for preparing porous structures and the flat surface etching of 4H-SiC. In this study, the effects of current density and KOH concentration on the etching of 4H-SiC were investigated. We found that the respective mechanisms for preparing porous structures and flat surface etching differed. The porous and flat etching modes were proposed to clarify the mechanistic differences. In addition, we achieved an etch rate of 1 μm h−1 in flat etching mode, and the sample surface was improved for 4H-SiC applications in the field of optoelectronics and microelectronics through the thermal oxidation of SiC.
Performance-based model-free adaptive finite-time control for shape memory alloy actuated swing platform
Authors: Liu Hongshuai , Xiao Jichun , Cheng Qiang , Hao Lina , Gao Haoze
Published: April 2023

Shape memory alloy (SMA), a kind of smart material, can be used as an actuator in many fields; however, its strong nonlinearity and parameter uncertainty hinders its application in high-tracking accuracy tasks. This paper addresses the tracking control problem of the SMA actuated swing platform suffering from completely unknown nonlinear model information and prescribed finite-time error constraints. First, the equivalent dynamic linearization model of the swing platform is established, and the unknown disturbance is estimated and compensated by the extended state observer. Meanwhile, a novel discrete-time performance function is proposed, and the prescribed finite-time tracking error constraints are transformed into a new equivalent unconstrained task. Second, the model-free adaptive sliding mode controller is designed using the unconstrained error, and the complete control law, including sliding mode control law and equivalent control law, is derived. Third, the stability of the closed-up swing platform is guaranteed by employing the Lyapunov method. Finally, experiments reveal that the proposed method is preferable.
Development and assessment of simplified analytical method for current distribution among REBa2Cu3O
y
parallel conductors in armature windings for fully superconducting rotating machines
Authors: Miura S , Kobun A , Masuda Y , Miyazaki H , Kawagoe A , Sasa H , Yoshida K , Sato S , Iwakuma M
Published: April 2023

Fully superconducting rotating machines employing REBa2Cu3O
y
(REBCO, RE = rare earth elements or Y) superconducting armature and field coils, are particularly interesting for aircraft applications, owing to their high output power density (kW kg−1). To achieve high current capability in superconducting coils, we have proposed a cabling design for transposed multi-strand parallel conductors. In the parallel conductor design, the REBCO strands are insulated from each other, except for both terminal ends, and transposed during the winding process to achieve uniform current distribution by cancellation of interlinkage magnetic flux between the strands. In this study, a simplified analytical method considering inductances was developed based on Laplace’s equation in cylindrical coordinates to roughly calculate the current distributions of multi-strands under armature coil conditions. The validity of the analytical method was investigated through current distribution measurements of the sample coils wound with two-strand parallel conductors. Consequently, the analytical method was validated with approximately 10% deviation under the experimental coil conditions. To establish a more accurate analysis method, certain improvements are needed.
Anion type-dependent confinement effect on glass transitions of solutions of LiTFSI and LiFSI
Authors: Zhang Jinbing , Wang Fengping , Cao Zexian , Wang Qiang
Published: April 2023

We present findings on the effect of nanometer-sized silica-based pores on the glass transition of aqueous solutions of lithium bis(trifluoromethane)sulfonimide (LiTFSI) and lithium difluorosulfimide (LiFSI), respectively. Our experimental results demonstrate a clear dependence of the confinement effect on the anion type, particularly for water-rich solutions, in which the precipitation of crystalized ice under cooling process induces the formation of freeze-concentrated phase confined between pore wall and core ice. As this liquid layer becomes thinner, the freeze-concentrated phase experiences glass transition at increasingly higher temperatures in solutions of LiTFSI. However, differently, for solutions of LiFSI and LiCl, this secondary confinement has a negligible effect on the glass transition of solutions confined wherein. These different behaviors emphasize the obvious difference in the dynamic properties’ response of LiTFSI and LiFSI solutions to spatial confinement and particularly to the presence of the hydrophilic pore wall.
Effects of resistivity and viscosity on dynamic evolution and radial position change of m/n = 3/1 double tearing mode
Authors: Lu X.Q. , Guo W. , Ma Z.W. , Zhang H.W. , Guo W.F.
Published: April 2023

The effects of the plasma resistivity and viscosity on the dynamic evolution of the m/n = 3/1 double tearing mode (DTM) are studied and analyzed quantitatively using the CLT (Ci-Liu-Ti, which means magnetohydrodynamics in Chinese) code. In this work, we mainly focus on the change in the radial positions and the oscillatory dynamics of the magnetic islands grown on the two rational surfaces. We conduct a systematic investigation on the effect of viscosity on the DTM dynamics, which has rarely been studied before. From the results of the study, it is observed that the time required for entering the explosive phase decreases with decreasing viscosity. In the nonlinear phase, the kinetic energy exhibits an oscillatory behavior due to the magnetic flux injection and magnetic reconnection, and the oscillation amplitude is suppressed for a large viscosity due to dissipation. The effects of the plasma resistivity and viscosity on the change in the radial positions of magnetic islands are systematically explained. The change in the radial positions of magnetic islands occurs in an abrupt growth phase before the kinetic energy reaches its maximum value. Multiple position changes take place with a relatively higher reconnection rate and magnetic flux injection at low viscosity damping. A large range of radial vortices formed as a result of the change in the positions may have a positive effect on the transport.
Energy and particle balance during plasma detachment in a long-leg divertor configuration
Authors: Masline R. , Krasheninnikov S.I.
Published: April 2023

Comprehensive studies of energy and particle balances in the transition to plasma detachment in an alternative divertor configuration with long outer legs are shown. Numerical simulations are performed with the 2D code suite SOLPS 4.3, using a disconnected double null grid with narrow, tightly baffled long poloidal leg divertors at the outer lower target and outer upper target. A particle count scan is performed using the ‘closed gas box’ model, where the tunable parameter in the simulations is the total number of deuterium particles in the simulation space and all other parameters are held fixed, including a constant input power and trace neon impurity radiation, to assess the physics of the transition to detachment in the system as the particle count increases. Three main aspects of the physics of divertor detachment are addressed: the criteria for the local onset of divertor detachment in each of the divertors, the distribution of heat flux and other plasma parameters between the four divertors as each divertor transitions to detachment, and the role of perpendicular transport in the transition to the detached regime. A synergistic mechanism by which the cross-field transport is reduced by factors associated with the onset of plasma recombination effects is identified. These results are compared to the existing understanding of the physics of the transition to plasma detachment in standard divertors.
Willingness to cooperate in shared natural resource management is linked to group identification through perceived efficacy and group norms
Authors: Rabinovich Anna , Walker Lindsay , Gohil Deepali , Njagi Tim , Currie Thomas E
Published: April 2023

Cooperative management of shared natural resources is one of the most urgent challenges the world is facing today. While there have been advances in understanding institutional design features that enable sustainable management, there are few field studies that provide theory-based insights into social psychological predictors of willingness to cooperate around shared resources. Here, we address this issue in the context of shared land management in pastoralist community conservancies in Kenya. In a large survey of individuals from different conservancies, we test a path model that links willingness to cooperate to how strongly respondents identified with their conservancy. This relationship is mediated by how efficient conservancies were perceived to be, and to what extent other people in the community were perceived to share cooperative norms. The results also point towards several parameters that may be conducive to developing stronger conservancy identification: transparency of purpose, motive alignment, sense of ownership, and demonstrating benefit. The findings provide insights into the social psychological processes that impact whether cooperative outcomes can be achieved in real-world shared resource settings, and offer practical implications for strengthening governance within pastoralist conservancies and related shared natural resource management contexts.
Reply to the Comment on ‘The operational foundations of PT-symmetric and quasi-Hermitian quantum theory’
Authors: Alase Abhijeet , Karuvade Salini , Maria Scandolo Carlo
Published: April 2023

This document is our reply to the Comment (Miloslav Znojil 2023 J. Phys. A: Math. Theor.
56 038001) on our recent work titled ‘The operational foundations of PT-symmetric and quasi-Hermitian quantum theory’. The original Comment consists of three addenda to our work. The first addendum claims that our work is ill-motivated as the motivating question, namely whether PT-symmetric quantum theory extends the standard quantum theory, was already answered in the literature. The second addendum points to some missing references in our work, and the third addendum suggests what constraints could lead to an extension of standard quantum theory. In our reply, we explain that the claim in the first addendum is a result of a misinterpretation of our motivating question. When interpreted correctly, the third addendum in the Comment in itself elaborates on why our motivating question is interesting and relevant. We also briefly comment on the prospects of an extension of standard quantum theory along the lines suggested in the third addendum. As our response to the second addendum, we explain our rationale behind citing certain references while leaving out others.