bluuebunny/crossref_metadata_2025 huggingface dataset:
Linearly-coupled sigmoid bistable stochastic resonance for weak signal detection
Authors: Zong Ping , An Ran , Zhang Chi , Wang Hongyu
Published: May 2024

The paper focuses on developing a stochastic resonance (SR) system designed for the detection of weak signals under alpha-stable-distributed noises. Initially, in view of the strong impulsive characteristics of noises, a linearly-coupled sigmoid bistable stochastic resonance (LSBSR) system is proposed, which is constructed by potential function and sigmoid function. Through formula derivation, it is theoretically proved that the output signal-to-noise ratio (SNR) of the LSBSR system is superior to that of the classical bistable SR system. Then, a new signal processing strategy based on the LSBSR system is introduced. Simulation experiments have demonstrated that under the input SNR = −20 dB, the detection probability of the LSBSR system exceeds 95% for the alpha-stable-distributed noise with α= 1.5. When α is reduced to 0.1, the detection probability approaches 80%, significantly outperforming other detection methods. Finally, the LSBSR system is applied to detect sea-trial signals with an SNR improvement of 22.5 dB, which further validates the practicability of the proposed system.
A visual area detection algorithm based on mirror splicing for motorcycle indirect vision test
Authors: Li Yuhua , Liu Zifeng , Jiang Shan , Yang Zhiyong , Li Bowen , Zhou Zeyang
Published: May 2024

Motorcycle indirect vision devices are important safety components, and the visual area is required to meet industry standards. There is a need for effective algorithms to detect and analyze the relevant visual areas within these mirrors to enhance motorcycle safety. However, it is a challenge to test rearview mirror vision in unstructured environments given variations in illumination, occlusion, and object scale. We propose a visual area detection algorithm based on mirror stitching for a motorcycle indirect vision test. First, an edge-based VGG16-Unet (EBV16-Unet) network is employed to extract binocular mirror information and eliminate the complex background. Second, gradient-based topology-preserving image stitching and multi-band hybrid Laplacian pyramid-based image blending algorithms are utilized to complete binocular mirror information acquisition. Finally, a sequential detection method for adaptive marker color and shape features is used to establish the visual area. The EBV16-Unet algorithm achieved an accuracy of 98.63% for precision, 98.71% for recall, 98.58% for F1, and 98.37% for mean intersection-over-union (MIOU), surpassing the comparative models of PSPNet, DeepLab v3+, and HRNet and exhibited superior generalization ability. The binocular vision splicing effect experiment revealed a horizontal splicing error of 0.114322 ± 0.0674 and vertical splicing error of 0.124287 ± 0.063302, calculated using a standard checkerboard. The rearview mirror vision test operation experiment results confirm that the Motorcycle Indirect Vision Test System (MIVTS) offers convenience, simplicity and high accuracy. MIVTS successfully accomplishes the unstructured motorcycle rearview mirror vision test, thereby establishing an advanced theoretical foundation for computer vision-based automated vehicle inspection.
Identifying sub-cascades from the primary damage state of collision cascades
Authors: Bhardwaj Utkarsh , Warrier Manoj
Published: May 2024

The morphology of a collision cascade is an important aspect in understanding the formation of defects and their distribution. While the number of sub-cascades is an essential parameter to describe the cascade morphology, the methods to compute this parameter are limited. We present a method to compute the number of sub-cascades from the primary damage state of the collision cascade. Existing methods analyze peak damage state or the end of ballistic phase to compute the number of sub-cascades which is not always available in collision cascade databases. We use density based clustering algorithm from unsupervised machine learning domain to identify the sub-cascades from the primary damage state. To validate the results of our method we first carry out a parameter sensitivity study of the existing algorithms. The study shows that the results are sensitive to input parameters and the choice of the time-frame analyzed. On a database of 100 collision cascades in W, we show that the method we propose, which analyzes primary damage state to predict number of sub-cascades, is in good agreement with the existing method that works on the peak state. We also show that the number of sub-cascades found with different parameters can be used to classify and group together the cascades that have similar time-evolution and fragmentation. It is seen that the number of SIA and vacancies, % defects in clusters and volume of the cascade, decrease with increase in the number of sub-cascades.
Resistive gas sensors for the detection of NH3 gas based on 2D WS2, WSe2, MoS2, and MoSe2: a review
Authors: Mirzaei Ali , Alizadeh Morteza , Ansari Hamid Reza , Moayedi Mehdi , Kordrostami Zoheir , Safaeian Haniyeh , Lee Myoung Hoon , Kim Tae–Un , Kim Jin–Young , Kim Hyoun Woo , Kim Sang Sub
Published: May 2024

Transition metal dichalcogenides (TMDs) with a two-dimensional (2D) structure and semiconducting features are highly favorable for the production of NH3 gas sensors. Among the TMD family, WS2, WSe2, MoS2, and MoSe2 exhibit high conductivity and a high surface area, along with high availability, reasons for which they are favored in gas-sensing studies. In this review, we have discussed the structure, synthesis, and NH3 sensing characteristics of pristine, decorated, doped, and composite-based WS2, WSe2, MoS2, and MoSe2 gas sensors. Both experimental and theoretical studies are considered. Furthermore, both room temperature and higher temperature gas sensors are discussed. We also emphasized the gas-sensing mechanism. Thus, this review provides a reference for researchers working in the field of 2D TMD gas sensors.
A new approach for the regularity of weak solutions of the 3D Boussinesq system
Authors: Chamorro Diego , Mîndrilă Claudiu
Published: May 2024

We address here the problem of regularity for weak solutions of the 3D Boussinesq equation. By introducing the new notion of partial suitable solutions, which imposes some conditions over the velocity field only, we show a local gain of regularity for the two variables

u
→

and θ.
Green synthesis and photocatalytic proficiency of tunable SnO2 nanostructures: unveiling environmental-friendly strategies for sustainable water remediation
Authors: Gupta Shalu , Kumar Rakesh
Published: May 2024

This study demonstrates a proficient and eco-friendly synthesis of SnO2 nanostructures using a hydrothermal method, without the requirement of extra surfactants. The synthesis was systematically performed by adjusting the molar ratio of stannic chloride to sodium hydroxide and varying the pH settings. It was noted that the pH value rises according to the concentration of sodium hydroxide. A comprehensive analysis was performed to characterize the resulting nanostructures, which involved studying their structural features, chemical composition, morphology, and optical properties. An x-ray diffraction analysis showed that increasing the pH values resulted in a noticeable improvement in the crystalline structure and a decrease in the density of surface defects. The SnO2 nanostructures, synthesized using different pH settings, were subsequently assessed for their photocatalytic performance in the degradation of methylene blue dye under simulated solar irradiation. Surprisingly, the nanostructure produced at higher pH levels showed outstanding results, as 97% of the dye was broken down in just 70 min when exposed to simulated solar radiation. The analysis uncovered a maximum rate constant (k) value of 0.04 min−1, determined using pseudo first-order rate kinetics. In order to better understand the photodegradation process, scavenger experiments were performed to identify the active species involved. These investigations provided valuable insights into the complex mechanisms that drive the observed photocatalytic activity. This study not only enhances the progress of SnO2 nanostructures but also highlights their potential as strong and environmentally friendly materials for effective photocatalytic applications.
Parameter characterization of variable bending stiffness module with electrostatic layer jamming based on giant electrorheological fluid
Authors: Sun Yi , Chen Ce , Liao Ningbin , Jia Wenchuan , Wang Min , Ding Jiheng , Pu Huayan , Yang Yi
Published: May 2024

Soft grippers exhibit good adaptability, but their grasping performance is limited. Variable-stiffness technology has been applied to soft grippers to address this problem. Therefore, a variable bending stiffness module (VBSM) with electrostatic layer jamming based on a giant electrorheological fluid (ELJ-GERF) for soft robots is proposed in this study, which exhibits a faster response time and a wider range of stiffness variation. A VBSM prototype is fabricated, and a theoretical model is established. The stiffness is mainly affected by the electrode quantity, overlapping area of electrode plates, insulator and conductive layers’ thickness, medium thickness and the exciting voltage. Direct current (DC) voltage experiments and alternating current (AC) voltage experiments were conducted on the test samples of filled with air (ELJ-AIR), silicone oil (ELJ-OIL), and ELJ-GERF. The experimental result show that stiffness-regulation of the VBSM can be achieved by adjusting the exciting voltage, and AC voltage being more suitable for regulating the stiffness of the VBSM than DC voltage. For AC voltage, the stiffness of ELJ-GERF increases to 53.5 times when a 4 kV voltage is applied. The stiffness variation range is about 2 to 3 times greater than that of ELJ-AIR or ELJ-OIL. Through the stiffness characterization experiment, the stiffness of the VBSM in this study is influenced by the viscosity of the GERF and the gap between the electrode plates. Through the capacitance test, the VBSM exhibits self-sensing ability. Finally, the VBSM is applied to a soft gripper, the vibration performance and variable stiffness performance in its application are verified.
Properties of NbxTi(1−x)N thin films deposited on 300 mm silicon wafers for upscaling superconducting digital circuits
Authors: Lozano Daniel Pérez , Soulié Jean-Philippe , Hodges Blake , Piao Xiaoyu , O’Neal Sabine , Valente-Feliciano Anne-Marie , Herr Quentin , Tőkei Zsolt , Kim Min-Soo , Herr Anna
Published: May 2024

Scaling superconducting digital circuits requires fundamental changes in the current material set and fabrication process. The transition to 300 mm wafers and the implementation of advanced lithography are instrumental in facilitating mature CMOS processes, ensuring uniformity, and optimizing the yield. This study explores the properties of Nb
x
Ti(1−x)N films fabricated by magnetron DC sputtering on 300 mm Si wafers. As a promising alternative to traditional Nb in device manufacturing, Nb
x
Ti(1−x)N offers numerous advantages, including enhanced stability and scalability to smaller dimensions, in both processing and design. As a ternary material, Nb
x
Ti(1−x)N allows engineering material parameters by changing deposition conditions. The engineered properties can be used to modulate device parameters through the stack and mitigate failure modes. We report characterization of Nb
x
Ti(1−x)N films at less than 2% thickness variability, 2.4% T
c variability and 3% composition variability. Film resistivity (140–375 Ωcm) shows a strong correlation with the film oxygen content, while the critical temperature T
c (4.6 K–14.1 K) is strongly affected by film stoichiometry and its microstructure has only a moderate effect on modifying T
c. Our results offer insights about the interplay between film stoichiometry, film microstructure and critical temperature.
Using machine learning to predict gamma shielding properties: a comparative study
Authors: Nahool T A , Abdelmonem A M , Ali M S , Yasser A M
Published: May 2024

This study employed machine learning (ML) algorithms to predict the linear attenuation coefficients (LACs) of materials in inorganic scintillation detectors, which are crucial for evaluating self-shielding properties. Predictions from various ML models were compared with results from the Phy-X/PSD program across different photon energies. The Gradient Boosting Regressor (GBR) model was identified as the most accurate model, achieving a testing set accuracy of 96.40%. This research showcases the potential of ML for efficiently and accurately estimating LACs, with the GBR model showing promise for applications in radiation detection and material science.
Effect of relaxation on the transfer of orbital angular momentum via four-wave mixing process in the four-level double lambda atomic system
Authors: Kumar Rohit , Manchaiah Dixith , Ahmad Mobassir , Easwaran Raghavan K
Published: May 2024

In this work, we have theoretically studied the resonant four-wave mixing (FWM) in a four-level double Lambda (Λ) atomic system in connection with orbital angular momentum (OAM) transfer from probe to generated signal beam. The effect of the relaxation process is studied in the forward as well as backward FWM. Based on the semiclassical model, our analysis shows a strong dependence of conversion efficiency on spontaneous decay and decoherence rates. From the intensity and phase profile, we have confirmed the OAM nature of the generated signal beam. The physical explanation is given for the dependence of efficiency on the decay rate of the excited atomic state. We have shown that decoherence present in the system always leads to a deleterious effect on conversion efficiency. Our presentation treats forward and backward FWM in a unified way in the context of OAM transfer and sheds light on the parameter dependence of conversion efficiency.
An excellent super-polarization-independent optical directional coupler based on dual-core photonic crystal fibre with a bandwidth of 390 nm
Authors: Zou Hui , Xu Jianjie , Jiang Menglin , Chen Yu
Published: May 2024

In this work, a novel structure of dual-core photonic crystal fibre (PCF) is proposed to realize the super-polarization-independent optical directional coupler, based on the feasibility of optical fibre manufacturing process and the need of practical application into account. The introduced fluorine-doped elliptical cores with a rotation angle of 45 degrees successfully realize the super-polarization-independent coupling performance within the effective wavelength range of 1230–1620 nm, with a difference in coupling ratios between two polarized lights of less than 0.004%. In other words, it counteracts the negative effects of the introduction of dual cores on the structure’s symmetry. This greatly reduces the difference in coupling ratio between the two polarization states and effectively eliminates the polarization-dependence of the dual-core PCF. In addition, when compared to traditional elliptical air holes, the solid elliptical structure offers greater ease of control, making manufacturing less challenging. Consequently, this innovative structure is poised for widespread adoption in today’s optical communication networks.
Reversible image secret sharing based on quantum logistic mapping and Chinese remainder theorem
Authors: Yang Yu-Guang , Liu Chang , Zhou Yi-Hua , Shi Wei-Min , Jiang Dong-Hua , Liao Xin
Published: May 2024

A reversible image secret sharing algorithm is proposed based on quantum logistic mapping and Chinese remainder theorem. In this algorithm, the hash value of the original image is generated using the SHA-3 algorithm, and then encrypted using the RSA algorithm to obtain the encrypted hash value and the public key, which are the initial values in the quantum logistic mapping equations. Next, the quantum logistic mapping algorithm will be utilized to generate the chaotic sequence. After scrambling the original image matrix with the chaotic sequence, the pre-encryption part will be completed. Finally, the cover images are binarized and then the pre-encrypted secret image is embedded into them, adding the Chinese remainder theorem. According to the simulation results, the present algorithm improves the key sensitivity of Chinese remainder theorem-based image secret sharing and has high robustness to salt and pepper noise and cut-off attack.
Research on water equivalence and angle dependence of medical POF scintillation dosimeters
Authors: Yu Junchang , Zhang Qing , Zhao Kexin , Zhang Hongquan
Published: May 2024

In radiation dosimetry and medical dosimetry, optical fiber dosimeters have great advantages in application due to their small size and long transmission distance. However, in some low-dose radiation environments, the water inequivalence error and angle error of optical fiber dosimeters can have significant impacts that cannot be ignored. In this paper, the effects of ray energy, ray solid angle and optical fiber probe size on water inequivalence error and angle error are analyzed by using Monte Carlo simulation. Due to the complexity of the influencing factors of the angle error, which is difficult to be analyzed precisely and quantitatively, a correction method based on BP neural network is proposed. The final validation results demonstrate that the correction scheme can reduce the total angle error of the optical fiber dosimeter to

2.72
%
.
Semiclassical dynamics of a superconducting circuit: chaotic dynamics and fractal attractors
Authors: Stirpe Davide , Manninen Juuso , Massel Francesco
Published: May 2024

We study here the semiclassical dynamics of a superconducting circuit constituted by two Josephson junctions in series, in the presence of a voltage bias. We derive the equations of motion for the circuit through a Hamiltonian description of the problem, considering the voltage sources as semi-holonomic constraints. We find that the dynamics of the system corresponds to that of a planar rotor with an oscillating pivot. We show that the system exhibits a rich dynamical behaviour with chaotic properties and we present a topological classification of the cyclic solutions, providing insight into the fractal nature of the dynamical attractors.
Compressive sensing–based optical two-frequency continuous wave time-of-flight ranging system
Authors: Thanh Vu Tung , Tran Thuc Van , Pham Quang Duc
Published: May 2024

A time-of-flight–based ranging system constructed using an intensity-modulated light source and photodetectors (PDs) is proposed. In the proposed system, the carrier wave, which comprises two cosine waves with different frequencies in the megahertz range, is reconstructed from a few samples obtained using PDs with kilohertz sampling rates using the compressive sensing technique. This allows the system to measure distances with very high accuracy and extends the measurement range while maintaining the accuracy of an existing system that uses a single-frequency carrier.
Electronic, elastic, and thermodynamic properties of complex hydrides XAlSiH (X = Sr, Ca, and Ba) intended for hydrogen storage: an ab-initio study
Authors: Ammi H , Charifi Z , Baaziz H , Ghellab T , Bouhdjer L , Adalla S
Published: May 2024

The mechanical and thermodynamic properties of polyanionic hydrides XAlSiH (X = Sr, Ca, and Ba) were evaluated using density functional theory (DFT). The thermal parameters of XAlSiH hydrides, such as the Grüneisen parameter γ, heat capacity, and thermal expansion coefficient, were computed for the first time. The quasi-harmonic Debye model was used to determine these parameters over a range of pressures (0–40 GPa) and temperatures (0–1000 K). The gravimetric hydrogen storage capacities for BaAlSiH, SrAlSiH, and CaAlSiH were found to be 0.52%, 0.71%, and 1.05%, respectively. The hydrogen desorption temperatures for these compounds were also simulated at 748.90 K, 311.57 K, and 685.40 K. Furthermore, semiconducting behavior with an indirect bandgap value between 0.2 and 0.7 eV was exhibited by these compounds using the GGA and LDA approximation, and between 0.7 and 1.2 eV using the mBJ-GGA and mBJ-LDA approximation. Accurate elastic constants for single crystals were obtained from the calculated stress–strain relationships. The elastic constants for the XAlSiH compounds were significantly higher than those for other hydrides. The [001] direction was more compressible than the [100] direction in the hexagonal structure of XAlSiH. A lower bulk modulus than metallic hydrides was exhibited by these materials, indicating that XAlSiH compounds (X = Sr, Ca, and Ba) were highly compressible. The melting temperature for CaAlSiH was higher than that for SrAlSiH and BaAlSiH. Consequently, the decomposition temperature for XAlSiH (X = Sr and Ba) at which hydrogen was released from a fuel cell was lower than that for CaAlSiH. The bonding behavior of CaAlSiH was more directional than that of SrAlSiH and BaAlSiH. Brittle materials were XAlSiH (X = Sr, Ca, and Ba). Our PBE calculations yield linear compressibility and orientation-dependent Young’s modulus. Materials composed of hexagonal XAlSiH (where X represents Sr, Ca, or Ba elements) exhibit anisotropy in Young’s modulus but isotropy in bulk modulus.
Scaling solutions as Early Dark Energy resolutions to the Hubble tension
Authors: Copeland Edmund J. , Moss Adam , Sevillano Muñoz Sergio , White Jade M.M.
Published: May 2024

A wide class of scalar field models including Quintessence and K-essence have the
attractive property of tracker regimes, where the energy density stored in the field evolves so as
to mimic that of the dominant background component. During this evolution, for a brief period of
time, there is an increase in the energy density of the field as it spirals in towards its
attractor solution. We show that when the peak of this energy density occurs around the epoch of
equality, we can address a key requirement of early dark energy (EDE), postulated as a solution to
the Hubble tension. In particular we demonstrate how this can occur in a wide class of
Quintessence, axion and K-essence models, before showing that the Quintessence models suffer in
that they generally lead to sound speeds incompatible with the requirements of EDE, whereas the
K-essence and axion models can do a better job of fitting the data.
A self-similar model of galaxy formation and dark halo relaxation
Authors: Velmani Premvijay , Paranjape Aseem
Published: May 2024

We develop a spherical self-similar model for the formation of a galaxy through gas collapsing in an isolated self-gravitating dark matter halo. As is well known, the self-similarity assumption makes the problem eminently tractable by reducing it to a system of ordinary differential equations. We improve upon the existing literature on self-similar collapse in two ways. First, we include the effects of radiative cooling and the formation of a pseudo-disk at the center of collapse, in a parametrised manner. More importantly, we solve for the evolution of gas and dark matter simultaneously and self-consistently using a novel iterative approach. As a result, our model produces shell trajectories of both gas and dark matter that qualitatively agree with the results of full hydrodynamical simulations of self-gravitating systems. We discuss the impact of various ingredients such as the accretion rate, gas equation of state, disk radius and cooling rate amplitude on the evolution of the gas shells, although we leave the inclusion of stellar and black hole activity to future work. The self-consistent evolution of gas and dark matter allows us to study the response (or `quasi-adiabatic relaxation') of the dark matter trajectories to the presence of collapsing gas, an effect that has gained increasing importance recently in the context of precision estimates of small-scale statistics like the matter power spectrum. Our default configuration produces a relaxation relation in qualitative agreement with that seen in cosmological hydrodynamical simulations, and further allows us to easily study the impact of the model ingredients mentioned above. As an initial application, we vary one ingredient at a time and find that the accretion rate and gas equation of state have the largest impact on the relaxation relation, while the cooling amplitude plays only a minor role. Our model thus provides a convenient framework to rapidly explore the coupled nonlinear impact of multiple astrophysical processes on the mass and velocity profiles of dark matter in galactic halos, and consequently on observables such as rotation curves and gravitational lensing signals.
Suppression of matter density growth at scales exceeding the cosmic screening length
Authors: Eingorn M. , Yilmaz E. , Yükselci A.E. , Zhuk A.
Published: May 2024

One of the main objectives of modern cosmology is to explain the origin and evolution of cosmic structures at different scales. The principal force responsible for the formation of such structures is gravity. In a general relativistic framework, we have shown that matter density contrasts do not grow over time at scales exceeding the cosmic screening length, which corresponds to a cosmological scale of the order of two to three gigaparsecs at the present time, at which gravitational interactions exhibit an exponential cut-off. This is a purely relativistic effect.
To demonstrate the suppression of density growth, we have performed N-body simulations in a box with a comoving size of 5.632 Gpc/h and obtained the power spectrum of the mass density contrast. We have shown that it becomes independent of time for scales beyond the screening length as a clear manifestation of the cosmic screening effect.
Star Image Centering with Deep Learning. II. HST/WFPC2 Full Field of View
Authors: Casetti-Dinescu Dana I. , Baena-Gallé Roberto , Girard Terrence M. , Cervantes-Rovira Alejandro , Todeasa Sebastian
Published: May 2024

We present an expanded and improved deep-learning (DL) methodology for determining centers of star images on Hubble Space Telescope/Wide-Field Planetary Camera 2 (WFPC2) exposures. Previously, we demonstrated that our DL model can eliminate the pixel-phase bias otherwise present in these undersampled images; however that analysis was limited to the central portion of each detector. In the current work we introduce the inclusion of global positions to account for the point-spread function (PSF) variation across the entire chip and instrumental magnitudes to account for nonlinear effects such as charge transfer efficiency. The DL model is trained using a unique series of WFPC2 observations of globular cluster 47 Tuc, data sets comprising over 600 dithered exposures taken in each of two filters—F555W and F814W. It is found that the PSF variations across each chip correspond to corrections of the order of ∼100 mpix, while magnitude effects are at a level of ∼10 mpix. Importantly, pixel-phase bias is eliminated with the DL model; whereas, with a classic centering algorithm, the amplitude of this bias can be up to ∼40 mpix. Our improved DL model yields star-image centers with uncertainties of 8–10 mpix across the full field of view of WFPC2.
A generalized presentation of multi-caloric effects based on exterior derivative theory and its applications
*
Authors: Yin Jun
Published: May 2024

The emerging concept of multi-caloric effects, introduced in 2010, entails the application of multiple interplay fields to a thermodynamic system. While multi-caloric effects are the main focus of experimental endeavors, theoretical considerations fall short of providing a thorough understanding. This paper introduces a comprehensive presentation on multi-caloric effects, employing the method and theory of exterior derivative formations. It addresses every aspect of thermodynamic systems, showcasing its applicability to multi-caloric materials (both single-phase and multi-phase materials), and its adaptability to different scenarios (either in single or multiple force fields). The formulation of Maxwell relationships, characterized by their generality and universality, enables a clear prediction in entropy and temperature, facilitating a distinct identification between independent and interdependent contributions from multi-caloric effects. These insights hold significant importance in designing and developing specialized thermodynamic materials, optimizing functional performances and exploring innovative mechanisms.
Experimental evidence for the drift wave nature of the weakly coherent mode in ASDEX Upgrade I-mode plasmas
Authors: Herschel M. , Happel T. , Wendler D. , Griener M. , Kalis J. , Fischer R. , Manz P. , Stroth U. ,   the ASDEX Upgrade Team
Published: May 2024

The improved energy confinement mode (I-mode) is a potential candidate for future fusion power plants, as it combines ELM-free operation with good confinement. The unusual edge transport and turbulence in this regime is still not fully understood. This study analyzes the turbulent structure of the weakly coherent mode (WCM) in ASDEX Upgrade. Measurements from Doppler back-scattering and a thermal helium beam diagnostic are used to determine velocities of the background plasma and the WCM over multiple discharges. A phase velocity of the WCM of the order of 2–5 km s−1 in the electron diamagnetic drift direction is found, quantitatively close to a drift wave assuming negligible temperature fluctuations. A good agreement with a previously proposed mechanism behind the I-mode regime is observed. This marks the first experimental verification of a specific understanding of the WCM and the I-mode regime.
Experimental and simulation analysis of Weakly Coherent Modes in I-mode discharges on EAST
Authors: Liu Y.J. , Liu Z.X. , Xia T.Y. , Zhang T. , Liu A.D. , Liu J. , Deng C.C. , Ye K.X. , Geng K.N. , Li G.S. , Long F.F. , Li J.Y. , Li P.C. , Yang K.N. , Zang Q. , Ti A. , Zhao H.L. , Liu H.Q. , Li H. , Xie J.L. , Lan T. , Mao W.Z. , Zhou C. , Ding W.X. , Zhuang G. , Liu W.D. , Li G.Q. , Gao X.
Published: May 2024

This paper reports the recent observation of a weakly coherent mode (WCM) within a conventional reflectometer on EAST and successfully determines its poloidal wavenumber range. During the transition from the L-mode to I-mode, the line-averaged density remains nearly unchanged while a significant change is observed in the electron cyclotron emission (ECE) signals at the boundary. The difference between the signals for the two channels at the edge increased, coinciding with the appearance of the WCM and a simultaneous rise in the boundary electron temperature. Further investigation unveiled the modulating role of edge temperature ring oscillation (ETRO) (Liu et al 2020 Nucl. Fusion
60 126016) on high-frequency density fluctuations. Statistical results unveil an inverse relationship between the centeral frequency of the WCM and q
95. Simulation results provide additional insights, demonstrating that the simulated ‘WCM’ in the density fluctuations aligns with experimental data in terms of center frequency. Additionally, the radial distribution of the simulated ‘WCM’ closely corresponds to regions with the strongest electron temperature gradients. Finally, through a cross-correlation analysis of the simulated fluctuations, the following phase relationship for the wavenumber range of ‘WCM’ was observed:

α

T
~

e

>

α

n
~

i

∼

α

ϕ
~

>

α

T
~

i

.
In-beam test results of an RPC-based module for position-sensitive neutron detectors with timing readout
Authors: Canezin G. , Margato L.M.S. , Morozov A. , Blanco A. , Saraiva J. , Lopes L. , Fonte P. , Lai Chung Chuan , Svensson Per-Olof , Markaj G. , Piegsa Florian M.
Published: May 2024

Recently we have proposed a new concept of a thermal neutron
detector based on resistive plate chambers and 10B4C solid
neutron converters, enabling to readout with high resolution in both
the 3D position of neutron capture and the neutron time of flight
(ToF). In this paper, we report the results of the first beam tests
conducted with a new neutron RPC detection module, coupled to the
position readout units of a new design. The main focus is on the
measurements of the neutron ToF and identification of the converter
layer where the neutron is captured, giving the position along the
beam direction.
Evaluating the effects of different tree species on enhancing outdoor thermal comfort in a post-industrial landscape
Authors: Vatani Mehran , Kiani Kamyab , Mahdavinejad Mohammadjavad , Georgescu Matei
Published: May 2024

A frequently emphasized strategy to reduce the burden of heat in cities across the world is the implementation of street trees. Here, we examine the effects of deciduous and coniferous tree deployment on meteorological variables and pedestrian thermal comfort through analysis of the new dynamic thermal comfort (dPET) index, using the latest version of the computational fluid dynamics model ENVI-met. We performed on site observational measurements of air temperature (Ta), relative humidity (Rh), wind speed (Ws), and mean radiant temperature (MRT) at five different locations on the hottest day of summer 2023, in a post-industrial urban landscape located in Tehran, Iran. Observations were used to evaluate ENVI-met simulation performance and served as a baseline against which sensitivity experiments—based on a minimum (35%) and maximum (75%) intervention scenario for deciduous and coniferous trees—were compared against. Our analysis indicates that 35% and 75% deployment reduced Ta by 1.2 °C and 4.2 °C, respectively, for deciduous tree species, compared to a 0.9 °C and 3.1 °C reduction for coniferous species, during the hottest day of summer 2023. The maximum deployment scenario decreased MRT by approximately 60 °C and 43 °C for deciduous and coniferous tree deployment, respectively. The maximum tree deployment scenario decreased dPET by nearly 16 °C and 14 °C for deciduous and coniferous trees, respectively, during the time of day that diurnal heating is maximized. Our findings highlight micrometeorological and personalized thermal comfort effects associated with variable tree species type and extent through examination of a pedestrian’s ambulatory experience across diverse urban microclimates in a region of the world that is particularly understudied.
Phase space geometry of general quantum energy transitions
Authors: de Almeida Alfredo M Ozorio
Published: May 2024

The mixed density operator for coarsegrained eigenlevels of a static Hamiltonian is represented in phase space by the spectral Wigner function, which has its peak on the corresponding classical energy shell. The action of trajectory segments along the shell determine the phase of the Wigner oscillations in its interior. The classical transitions between any pair of energy shells, driven by a general external time dependent Hamiltonian, also have a smooth probability density. It is shown here that a further contribution to the transition between the corresponding pair of coarsegrained energy levels, which oscillates with either energy, or the driving time, is determined by four trajectory segments (two in the pair of energy shells and two generated by the driving Hamiltonian) that join exactly to form a closed compound orbit (CCO). In its turn, this sequence of segments belongs to the semiclassical expression of a compound unitary operator that combines four quantum evolutions: a pair generated by the static internal Hamiltonian and a pair generated by the driving Hamiltonian. The CCOs are shown to belong to continuous families, which are initially seeded at points where the classical flow generated by both Hamiltonians commute.
Probabilistic approach of solving burnup problems
Authors: Bala K A , Omar M R , Chin K F
Published: May 2024

This paper presents a new approach to solve nuclear burnup problems using a probabilistic method. Unlike the traditional methods that rely on complex matrix exponential calculations, the proposed method tracks the transformation of nuclei over a period of time, enabling the estimation of nuclide concentrations. The method is implemented in a C++ program CNUCTRAN and verified against the Chebyshev Rational Approximation Method (CRAM). Three sample calculations are presented, showing a detailed comparison of results obtained using CNUCTRAN and CRAM48. The relative error analysis emphasizes the accuracy of the probabilistic method, with the most significant error observed below 0.001%. The computational efficiency is discussed in terms of CPU time, indicating that CNUCTRAN requires more CPU time than CRAM but with improved accuracy as the time step decreases. The numerical results for various burnup problems demonstrate the accuracy and efficiency of the probabilistic method, making it a promising alternative for simulating realistic nuclear transmutations.
Depth dose measurement by using Al2O3 OSL dosimeters in high energy photons in the presence of air cavity and density inhomogeneity
Authors: Fahmi Mohd Yusof Mohd , Sauki Amirah , Ateqah Suzaini Nur , Nazirah Abdullah Arifah , Bazlie Abd Kadir Ahmad , Mohd Isa Norriza
Published: May 2024

Air cavities and tissue density inhomogeneity significantly affects the distribution of radiation doses, potentially resulting in adverse consequences such as cancer recurrence. This research aims to assess the accuracy of Al2O3 optically stimulated luminescence (OSL) dosimeters in measuring doses within varying thicknesses of air cavities (3, 5, and 8 cm) and tissue inhomogeneity of low and high density simulated by the lung and bone phantoms. An expanded polystyrene (EPS) was employed in homogeneous solid water® phantoms to simulate the air cavity. The percentage depth-dose (PDD) curves at 6 MV photons were obtained in both presence of air cavity and density inhomogeneity and compared to that in the EBT3 radiochromic film dosimeters and treatment planning system (TPS). The results indicated that the presence of an air cavity and tissue inhomogeneity affected the depth dose measured in OSL dosimeters, EBT3 films and TPS. OSLD and TPS showed good agreement at the centre of the cavity, which is within ±5% but could not estimate scattered radiation to the distal and proximal surfaces of the air cavity. The obtained p-values showed no significant differences of dose measured in OSL dosimeters compared to those in EBT3 films and TPS. The Kruskal Wallis test and Mann-Whitney showed no significant difference between OSL dosimeters, EBT3 film and TPS in the measurement of depth doses in the presence of density inhomogeneity. The overall results indicated the suitability of OSL dosimeters as indirect dosimeters for the measurements of depth dose in the presence of air cavity and tissue density inhomogeneity
Changes in crystallinity of sago palm (Metroxylon sago spp.) waste during cellulose extraction
Authors: Yacob N. , Yusof M.R. , Mohamed A.Z. , Badri K.
Published: May 2024

Sago palm (Metroxylon sago spp.) is one of the major agricultural plants in Malaysia. Sago pith waste (SPW), which is left behind after sago starch extraction, is disposed of by washing off into the nearby river. Reuse of SPW provides a solution to the problem of discarding the waste. In this study, cellulose has been extracted from SPW. The fibers were pretreated with 2% of aqueous sodium hydroxide (NaOH) solution before bleaching with an acidified sodium chlorite (NaClO2) and acetate buffer solution. The influence of NaOH and bleaching treatment on the cellulose crystallinity of SPW has been investigated using chemical analysis, Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD). From XRD analysis, the crystallinity index (CI) was calculated. The CI of SPW increased significantly by 110% after the chemical treatments. The FTIR analysis proved the dissolution of the non-cellulosic components by NaOH and NaClO2 treatments.
A study on surface air Beryllium-7 concentration at radionuclide station in Tanah Rata, Cameron Highlands (MYP42) during southwest monsoon seasons in Malaysia
Authors: Fauzi Haris Mohd , Norwawi Norita Md. , Hafez Mohd Isa Mohd , Rawi Mohamed Zin Muhammad , Zulfakar Zolkaffly Muhammed , Ta’at Azlai
Published: May 2024

Beryllium-7 (Be-7) is a significant radionuclide, primarily produced through cosmic ray interactions with atmospheric elements. Its study can provide insights into atmospheric processes and transport mechanisms. This research investigates the concentration of Be-7 in surface air at the Radionuclide Station (MYP42) located in Tanah Rata, Cameron Highlands, Malaysia, during the Southwest Monsoon season using data from the Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO) from 2011 to 2021. Meteorological parameters of the study area, such as wind direction, wind speed, humidity, and precipitation, are considered to understand their influence on radionuclide dispersion and deposition. The results from this study are aimed to contribute to the understanding of atmospheric dynamics in the Cameron Highlands region and may have implications for broader atmospheric and environmental studies. The study results suggest no statistically significant variation in Be-7 concentration during the southwest monsoon season, demonstrating minimal fluctuations within and outside the monsoon period. Such insights are crucial for the region’s scientific research and environmental management.
CTBT data for environmental radiological monitoring: a preliminary study in Malaysia
Authors: Baharuddin B , Yii M W , Yusof N F , Jaffary N A M , Kamaruddin A H C , Bakar A I A , Halmi A S Z M , Sanusi M S M. , Johan J S
Published: May 2024

Numerous anthropogenic nuclear activities in the Asia Pacific have exposed the region to radiological contamination risks, dating back to nuclear testing in 1946, with the most recent nuclear tests by North Korea. Additionally, the region had faced two major nuclear reactor disasters: the 1986 Chernobyl incident and the 2011 TEPCO Fukushima Nuclear Power accident. The latter led to the release of long-lived fission products from nuclear reactors, primarily volatile iodine and caesium isotopes into the atmosphere. These events have raised significant concerns for the international community, particularly neighbouring countries like Malaysia. Understanding atmospheric processes is essential for assessing the potential pathways of anthropogenic radionuclide transport and its impacts. Which later can be used to devise effective monitoring and mitigation strategies. This study, part of an environmental radiological monitoring initiative, utilises data from the CTBTO database. It aims to create a comprehensive mapping of anthropogenic radionuclide concentrations, focusing on Americium-241 (241Am), Caesium-137 (137Cs), Strontium-90 (90Sr), and Plutonium isotopes (239+240Pu) fallout in the Malaysia-South China Sea region. However, according to the CTBTO database, relevant anthropogenic radionuclide detected more than three years after the Fukushima incident is 137Cs. Employing ArcGIS and CTBTO data, the study examines the influence of the Northeast and Southwest Monsoons on 137Cs concentration mapping. these findings contribute to a global understanding of radionuclide distribution, with initial results showing the presence of detected anthropogenic radionuclide 137Cs in the Malaysian environment. The 2014 pattern became a piece of preliminary evidence that the Northeast Monsoon had slightly elevated concentrations in the Malaysian environment, indicating its influence on radionuclide movement
Generating real-scene hologram through light field imaging and deep learning
Authors: Wang Rui , Ai Lingyu , Wang Yinghui , Zhu Xiaolong , Ni Yuqing , Cho Myungjin
Published: May 2024

Addressing the challenge of acquiring holograms from real-world scenes, this study introduces a novel approach leveraging light field cameras to capture light field data, which is subsequently transformed into authentic scene holograms. This methodology integrates light field imaging technology with a pre-trained deep neural network. To compensate for the limitations inherent in camera hardware, a super-resolution algorithm is employed. The conversion of light field information into RGB-D data facilitates its input into the deep neural network, enabling the inference of corresponding real-world scene holograms. Empirical evidence demonstrates that the system is capable of inferring high-resolution (1920 × 1080) real-world scene holograms within a timeframe of 5 s, utilizing hardware comprising an NVIDIA RTX 3060.
The detection of unconventional quantum oscillations in insulating 2D materials
Authors: Wu Sanfeng
Published: May 2024

In strongly correlated quantum materials, electrons behave in ways that often extend beyond the confines of conventional Fermi-liquid theory. Interesting results include the observation of low-temperature metallic behavior in systems that are highly resistive. Here we provide an overview of experiments in which insulators exhibit characteristics of a metal such as the Shubnikov–de Haas-like quantum oscillations, focusing on recent findings in the correlated insulating states of two-dimensional WTe2. We discuss the status of current research, clarify the debates and challenges in interpreting the experiments, rule out extrinsic explanations and discuss promising future directions.
Optimization of investment portfolios of Chinese commodity futures market based on complex networks
Authors: Huang Ke , Ke Lifei , Zhang Zuominyang , Li Qiumei , Sun Jifeng
Published: May 2024

Futures trading in developing countries is now attracting more attention since investors may easily generate more excess return compared to the markets in developed countries, especially in Chinese market. In this paper, we analyzed the relationship between the centrality of commodity in the Chinese commodity futures market network and the optimal weight of each commodity in a portfolio, empirically examined the market systemic factors and commodity idiosyncratic factors that affect the centrality of commodity, and evaluated the effect of network structure on the optimization of commodity portfolio selection under the mean-variance framework. We found that the commodities with high network centrality are often related to industrial products with high volatility and small portfolio weights. We put forward a kind of commodity futures investment strategy based on this network and results showed that cumulative yield is better than other benchmark portfolios. The main contribution of this paper is to apply complex network theory to optimize futures portfolio selection by establishing the relationship between portfolio weight and commodity centrality in Chinese market, which is still under explored.
Low-loss α-tantalum coplanar waveguide resonators on silicon wafers: fabrication, characterization and surface modification
Authors: Lozano D P , Mongillo M , Piao X , Couet S , Wan D , Canvel Y , Vadiraj A M , Ivanov Ts , Verjauw J , Acharya R , Van Damme J , Mohiyaddin F A , Jussot J , Gowda P P , Pacco A , Raes B , Van de Vondel J , Radu I P , Govoreanu B , Swerts J , Potočnik A , De Greve K
Published: May 2024

The performance of state-of-the-art superconducting quantum devices is currently limited by microwave dielectric loss at different interfaces. α-tantalum is a superconductor that has proven effective in reducing dielectric loss and improving device performance due to its thin low-loss oxide. Here, we demonstrate the fabrication of high-quality factor α-tantalum coplanar-waveguide resonators directly on pristine 300 mm silicon wafers over a variety of metal deposition conditions and perform a comprehensive material and electrical characterization study. Additionally, we apply a surface treatment based on hydrofluoric acid that allows us to modify different resonators surfaces, leading to a reduction in two-level system loss in the devices by a factor of three. This loss reduction can be entirely attributed to the removal of surface oxides. Our study indicates that large scale manufacturing of low-loss superconducting circuits should indeed be feasible and suggests a viable avenue to materials-driven advancements in superconducting circuit performance.