bluuebunny/crossref_metadata_2025 huggingface dataset:
YES-SLAM: YOLOv7-enhanced-semantic visual SLAM for mobile robots in dynamic scenes
Authors: Liu Hang , Luo Jingwen
Published: December 2023

In dynamic scenes, moving objects will cause a significant error accumulation in robot’s pose estimation, and might even lead to tracking loss. In view of these problems, this paper proposes a semantic visual simultaneous localization and mapping algorithm based on YOLOv7. First, a light-weight network YOLOv7 is employed to acquire the semantic information of different objects in the scene, and flood filling and edge-enhanced techniques are combined to accurately and quickly separate the dynamic feature points from the extracted feature point set. In this way, the obtained static feature points with high-confidence are used to achieve the accurate estimation of robot’s pose. Then, according to the semantic information of YOLOv7, the motion magnitude of the robot, and the number of dynamic feature points in camera’s field-of-view, a high-performance keyframe selection strategy is constructed. On this basis, a robust loop closure detection method is developed by introducing the semantic information into the bag-of-words model, and global bundle adjustment optimization is performed on all keyframes and map points to obtain a global consistent pose graph. Finally, YOLOv7 is further utilized to carry out semantic segmentation on the keyframes, remove the dynamic objects in its semantic mask, and combine the point cloud pre-processing and octree map to build a 3D navigation semantic map. A series of simulations on TUM dataset and a case study in real scene clearly demonstrated the performance superiority of the proposed algorithms.
Slender defect segmentation network of workpiece surface based on deep learning
Authors: Chen Guodong , Xu Feng , Liu Guihua , Chen Chunmei , Lau Billy Pik Lik , Liu Ran , Yuen Chau
Published: December 2023

As a key part of the workpiece production process, workpiece surface defect segmentation detection plays an important role in the quality assurance of the workpiece. Aiming at the problem of low accuracy of workpiece surface slender defect segmentation, we propose a slender defect segmentation network based on feature enhancement module (FEM) and feature fusion module (FFM). Firstly, the ConvNeXt is improved and used as the backbone network. Then, the FEM is designed to obtain rich defect features. Finally, the FFM is designed to expand the receptive field and fuse shallow features with deep features to enhance the features of slender defects. The proposed method improves the segmentation accuracy of slender defects. The mean pixel accuracy) of slender defect segmentation on the self-built diode glass shell dataset and public magnetic sheet dataset is 97.87% and 94.86%, respectively. The mean Intersection over Union of slender defect segmentation is 94.32% and 83.89%, respectively. The segmentation speed reaches 43FPS, and the parameter is 7.12 M, which balances the segmentation accuracy, speed and model size.
Spatio-temporal dynamics of electrons and helium metastables in uniform dielectric barrier discharges formed in He/N2
Authors: Nawrath Niklas , Korolov Ihor , Bibinov Nikita , Awakowicz Peter , Gibson Andrew R
Published: December 2023

A uniform atmospheric pressure dielectric barrier discharge is operated in helium with an admixture (0.45%) of nitrogen. The discharge is ignited in the gas gap between a driven and a grounded electrode and propagates along the dielectric surface outside the gap. Plasma conditions are characterised with current and voltage measurements and by application of absolutely calibrated optical emission spectroscopy, with a focus on nitrogen molecular emission. Plasma parameters, namely electron density and reduced electric field, are determined with spatial and temporal resolution in the frame of a collisional-radiative model using a calibrated charge coupled device camera and Abel inversion of measured images. The density of an effective helium metastable state is calculated using the measured plasma parameters and compared with values of the

H
e

(

2

3

S

)

state density measured with tunable diode laser absorption spectroscopy.
Gallium phosphide (GaP) as a standard ultraviolet index detector: response comparison and measurements
Authors: Abdel Baset Yasmen , Hamed Sawsan , Reda Sameh , Farag Hamed , Abdel Ghany H A , Faramawy Samaa M
Published: December 2023

One of the significant metrics that has lately emerged as a result of climate change is the Ultraviolet Index (UVI). In this work, the authors established a standardized reference UVI radiometer at NIS, Egypt, and discussed the performance to cover the actual actinic spectrum. Selective commercial UVI radiometers based on the proposed detector's responsivity and spectral mismatch were compared to the standardized reference UVI radiometer. The result indicated that the established detector response covers the entire UV actinic spectrum (280–405 nm). Besides, the standardized reference UVI radiometer has the least spectrum mismatch value with the (CIE) spectral response, according to a comparison between it and the other detectors that have been evaluated. Furthermore, it has the highest occupied area under the CIE spectral response curve, which is about 73.8%, and has about 12% better performance. These findings support to use of the established detector as a reference standard for detecting UVI at the radiometry lab at NIS Egypt.
Frequency tunable switching between transmission and absorption modes based on graphene and VO2 layers at the THz range
Authors: Roumi Bita , Abdi-Ghaleh Reza , Jing Liqiao
Published: December 2023

In this paper, a tunable multilayer structure is proposed, which can provide reversible switching between transmission and absorption modes at the terahertz region without reconfiguration. The layered structure consists of graphene, Si, and VO2 layers. Transfer matrix method is employed to describe the optical properties of the layered structure. The switching phenomenon occurs based on the VO2 transition from insulator to metal phase by varying temperature. Furthermore, active frequency tuning by graphene chemical potential for thermally switching transmission and absorption with near-perfect intensity is observed. Incidence angular stability for TE and TM is up to

20
°

and

40
°
,

respectively. Finally, the Si layer thickness effect demonstrates that mainly defines the peak number and frequency for both functions. Theoretical implementation confirms the potential usefulness of the proposed configuration in applications such as reversibly tunable smart absorbers, filters, or thermo-optical switches for high-speed optical systems.
Penning ion source based surface modification of titanium by nitrogen ion implantation
Authors: Murtaza Ghulam , Siddique Muhammad Tariq , Shakeel-ur-Rehman  , Qayyum A , Shah Attaullah , Shah S I W
Published: December 2023

The nitrogen ions of the Penning ion source are bombarded on commercially available pure titanium substrates in pulses of about 5.6 μs duration. A thin film (∼500 nm) of multiphase titanium nitride is produced without additional heating of the substrate. The surface modification is studied for various energies of implanted ions at a low flux density. The 2.4 × 109 ions of specific energy are bombarded on the sample in each single pulse of the ion. Each sample is exposed to one thousand such pulses at a repetition rate of 0.1 Hz. The corresponding energy flux was transferred to the sample, promoting the growth of a thin nitride layer. X-ray diffraction (XRD) analysis demonstrates the formation of a monocrystalline multiphase titanium nitride thin film. The XRD spectra show the multiphase reflections of Ti4N2 (111), Ti9N3.87 (009), and Ti12N7 (0012) that depend on the energy of the ion beam. Ti4N2 is observed to be the dominant phase in this ion implantation process. The morphological and compositional changes of ion implanted samples are investigated using field emission scanning electron microscopy (SEM) along with energy dispersive x-ray spectroscopy (EDX). Raman scattering analysis of treated samples verified the XRD results. The penetration depth of nitrogen ions inside the titanium is calculated using the SRIM code. Vickers hardness has improved three times compared to the original sample.
Chaotic neural networks with complex-valued weight and its applications in electrocardiogram classification
Authors: Zhang Fangfang , Chen Luobing , Kou Lei , Hu Zhiqiang , Shu Minglei , Wang Gongming
Published: December 2023

As neural networks are easy to converge to local minimum, the ergodicity of chaotic system is helpful to tackle this problem. Besides, the real parts and imaginary parts in complex-valued chaotic systems are independent, which increase the ergodic property and unpredictability of the chaotic signals. Therefore, we propose a new chaotic neural network with complex-valued weight for electrocardiogram classification. Firstly, a complex Logistic chaotic map is put forward, and its bifurcation diagram, Lyapunov index, and chaotic attractors are analyzed. Secondly, based on the ergodicity of complex Logistic chaotic map and a novel neuron function, the learning algorithm including complex-valued weight iteration for the chaotic neural network is proposed. Finally, the MIT-BIH data-base is used to verify the proposed method. The chaotic neural network with real Logistic map and other classification methods are also adopted for comparison. The results show that our chaotic neural network has a certain improvement in the accuracy of electrocardiogram classification.
Partial regularity of suitable weak solution to a three-dimensional fractional parabolic-elliptic chemotaxis-Navier–Stokes system
Authors: Lei Yuzhu , Liu Zuhan , Zhou Ling
Published: December 2023

In this paper, we investigate a fractional parabolic-elliptic chemotaxis-Navier–Stokes system in spatial dimensions three and obtain the global existence of the suitable weak solution by a contraction mapping theorem. Furthermore, we improve the regularity of the solution through a local maximal L

p
regularity estimate for the fractional heat equation such that the suitable weak solution is smooth away from a closed set whose one-dimensional parabolic Hausdorff measure is zero, which extends the partial regularity theory of Caffarelli, Kohn and Nirenberg [10] on the Navier–Stokes equation to the fractional parabolic-elliptic chemotaxis-Navier–Stokes system.
Piecewise nonlinear resistor-capacitor shunted josephson junction circuit: dynamical and microcontroller implementation probing
Authors: Ayena Wenceslas Senakpon Coami , Venkatesh Jayaraman , Ainamon Cyrille , Ngongiah Isidore Komofor , Sekhar D Chandra , Rajagopal Karthikeyan
Published: December 2023

This paper exposes the theoretical and microcontroller implementation probing of the piecewise nonlinear resistor-capacitor shunted Josephson junction circuit (PNRCSJJC). The PNRCSJJC is characterized by no steady state when the applied current is greater than one and exhibits two steady states in which one is a focus and its counterpart a saddle-node for excitation current less than or equal to one with credit to the Routh–Hurwitz criterion. The PNRCSJJC exhibits periodic characteristics, quasi-periodic characteristics, varying structures of chaotic characteristics, and coexisting behaviors which is proved qualitatively by the microcontroller execution method. The polarity of the chaotic signal in the voltage state variable is flexibly altered by varying a constant parameter included in the rate equations of PNRCSJJC.
Hidden extreme multistability in a smooth flux-controlled memristor based four-dimensional chaotic system and its application in image encryption
Authors: Kamdoum Tamba Victor , Biamou Arsene Loic Mbanda , Tagne François Kapche , Takougang Armand Cyrille Nzeukou , Fotsin Hilaire Bertrand
Published: December 2023

This paper introduces and investigates the dynamic analysis of a four-dimensional chaotic system based on a flux-controlled memristor and its application in image encryption. The analysis of equilibrium points of the system shows that it has no equilibrium points and therefore belongs to the family of systems with hidden attractors. It is demonstrated by computational simulations that the system under study experiences rich and complicated dynamics such as coexisting hidden attractors, hidden extreme multistability, offset boosting dynamics and antimonotonicity. A physical circuit that can reproduce the complex behaviors of the system is constructed and realized. The results are in agreement with those from computational simulations. According to the interesting features of the system, it is exploited to generate random bits for image encryption. The robustness and efficiency of the designed image encryption algorithm are tested by providing some statistical tests and security performances. It is found that the designed image encryption algorithm is efficient and robust compared to other image encryption algorithms investigated in some other recent related works.
Inside the Jaynes–Cummings sum
Authors: Pavlik S I
Published: December 2023

It is shown that the atomic inversion in the Jaynes–Cummings model has an exact representation as an integral over the Hankel contour. For a field in a coherent state, the integral is evaluated using the saddle point method. The trajectories of saddle points as a function of time are on the branches of the multi-valued Lambert function. All of them start at the initial moment of time, but make the maximum contribution to the inversion at different times. If the collapse and the first revival are clearly distinguished, then subsequent revivals are determined by the comparable contributions of several trajectories.
Modification of the dipole in arrival directions of ultra-high-energy cosmic rays due to the Galactic magnetic field
Authors: Bakalová A. , Vícha J. , Trávníček P.
Published: December 2023

The direction and magnitude of the dipole anisotropy of ultra-high-energy cosmic rays with energies above 8 EeV observed by the Pierre Auger Observatory indicate their extragalactic origin. The observed dipole on Earth does not necessarily need to correspond to the anisotropy of the extragalactic cosmic-ray flux due to the effects of propagation in the Galactic magnetic field. We estimate the size of these effects via numerical simulations using the CRPropa 3 package. The Jansson-Farrar and Terral-Ferrière models of the Galactic magnetic field are used to propagate particles within the Galaxy. We identify allowed directions and amplitudes of the dipole outside the Galaxy that are compatible with the measured features of the dipole on Earth for various mass composition scenarios at the 68% and 95% confidence level.
Extracting spinning wormhole energy via Comisso-Asenjo process
Authors: Ye Xu , Wang Chao-Hui , Wei Shao-Wen
Published: December 2023

Recently, Comisso and Asenjo demonstrated that rapid magnetic reconnection is a promising approach to extract spinning black hole energy. In this paper, we focus on extracting spinning wormhole energy via such mechanism. The study shows that it is indeed possible to extract rotating energy from a spinning wormhole with small regularization parameter ℓ of the central singularity. The efficiency and power of the energy extraction are also evaluated. Quite different from the Kerr black hole, the spin of the wormhole can take arbitrarily large value. However, the increase in wormhole spin not always improves the efficiency and power of energy extraction. By further comparing with the Kerr black hole, we find the wormhole is more efficient when the magnetic reconnection happens within radial distance r/M < 1. These studies reveal the features of extracting spinning wormhole energy, and more underlying properties are expected to be disclosed for the horizonless objects.
Impact of different interaction behavior on epidemic spreading in time-dependent social networks
Authors: Huang 黄 Shuai 帅 , Chen 陈 Jie 杰 , Li 李 Meng-Yu 梦玉 , Xu 徐 Yuan-Hao 元昊 , Hu 胡 Mao-Bin 茂彬
Published: December 2023

We investigate the impact of pairwise and group interactions on the spread of epidemics through an activity-driven model based on time-dependent networks. The effects of pairwise/group interaction proportion and pairwise/group interaction intensity are explored by extensive simulation and theoretical analysis. It is demonstrated that altering the group interaction proportion can either hinder or enhance the spread of epidemics, depending on the relative social intensity of group and pairwise interactions. As the group interaction proportion decreases, the impact of reducing group social intensity diminishes. The ratio of group and pairwise social intensity can affect the effect of group interaction proportion on the scale of infection. A weak heterogeneous activity distribution can raise the epidemic threshold, and reduce the scale of infection. These results benefit the design of epidemic control strategy.
Chimera states of phase oscillator populations with nonlocal higher-order couplings
Authors: Wu 伍 Yonggang 勇刚 , Yu 余 Huajian 华健 , Zheng 郑 Zhigang 志刚 , Xu 徐 Can 灿
Published: December 2023

The chimera states underlying many realistic dynamical processes have attracted ample attention in the area of dynamical systems. Here, we generalize the Kuramoto model with nonlocal coupling incorporating higher-order interactions encoded with simplicial complexes. Previous works have shown that higher-order interactions promote coherent states. However, we uncover the fact that the introduced higher-order couplings can significantly enhance the emergence of the incoherent state. Remarkably, we identify that the chimera states arise as a result of multi-attractors in dynamic states. Importantly, we review that the increasing higher-order interactions can significantly shape the emergent probability of chimera states. All the observed results can be well described in terms of the dimension reduction method. This study is a step forward in highlighting the importance of nonlocal higher-order couplings, which might provide control strategies for the occurrence of spatial–temporal patterns in networked systems.
Source localization in signed networks with effective distance
Authors: Ma 马 Zhi-Wei 志伟 , Sun 孙 Lei 蕾 , Ding 丁 Zhi-Guo 智国 , Huang 黄 Yi-Zhen 宜真 , Hu 胡 Zhao-Long 兆龙
Published: December 2023

While progress has been made in information source localization, it has overlooked the prevalent friend and adversarial relationships in social networks. This paper addresses this gap by focusing on source localization in signed network models. Leveraging the topological characteristics of signed networks and transforming the propagation probability into effective distance, we propose an optimization method for observer selection. Additionally, by using the reverse propagation algorithm we present a method for information source localization in signed networks. Extensive experimental results demonstrate that a higher proportion of positive edges within signed networks contributes to more favorable source localization, and the higher the ratio of propagation rates between positive and negative edges, the more accurate the source localization becomes. Interestingly, this aligns with our observation that, in reality, the number of friends tends to be greater than the number of adversaries, and the likelihood of information propagation among friends is often higher than among adversaries. In addition, the source located at the periphery of the network is not easy to identify. Furthermore, our proposed observer selection method based on effective distance achieves higher operational efficiency and exhibits higher accuracy in information source localization, compared with three strategies for observer selection based on the classical full-order neighbor coverage.
Controlled thermally-driven mass transport in carbon nanotubes using carbon hoops
Authors: Li 李 Yaolong 耀隆 , Li 李 Songyuan 松远 , Wang 王 Meifen 美芬 , Zhang 张 Renliang 任良
Published: December 2023

Controlling mass transportation using intrinsic mechanisms is a challenging topic in nanotechnology. Herein, we employ molecular dynamics simulations to investigate the mass transport inside carbon nanotubes (CNT) with temperature gradients, specifically the effects of adding a static carbon hoop to the outside of a CNT on the transport of a nanomotor inside the CNT. We reveal that the underlying mechanism is the uneven potential energy created by the hoops, i.e., the hoop outside the CNT forms potential energy barriers or wells that affect mass transport inside the CNT. This fundamental control of directional mass transportation may lead to promising routes for nanoscale actuation and energy conversion.
Research on Residual Flux Measurement Method for Power Transformers
Authors: Chen Haotian , Dou Zhenlan , Yu Jiang , Chen Wei , Sun Pei , Zhang Chunyan
Published: December 2023

The residual flux of power transformers is an important factor affecting the inrush current. In order to solve the problem of residual flux measurement of power transformers, this paper proposes an indirect measuring method of residual flux based on the first peak value of inrush current. Through the investigation of the relationship between the inrush current, closing angle and residual flux, the value of residual flux can be measured by measuring the inrush current with controlled closing angle of different conditions, and the accuracy and validity of the residual flux measurement method is verified by experiment.
Improving the Flexibility of the Distribution Network Based on the Robust Chance Constraint Method
Authors: Chen Zhengping , Huang Minghua , Chen Feixiong , Li Wenzong , Shao Zhenguo , Xu Zhengqi , Wang Fangdong , Su Weiqi
Published: December 2023

While the large-scale access to distributed new energy brings economic and environmental benefits, its inherent uncertainty characteristics also trigger problems such as voltage overruns and fluctuations. In order to effectively solve the adverse effects of large-scale grid connection of distributed new energy, this paper proposes the optimization method of regional autonomy capacity based on the robust chance constraint model. First, the regional autonomy capacity measurement method based on distribution robust optimization is studied, and the regional autonomy robust chance constraint model containing distributed energy is constructed. Second, the active distribution network scheduling model is studied to achieve the optimization of regional self-energy capacity. Finally, simulation examples show that the proposed approach can fully utilize the flexible resources within the distribution network and effectively improve the autonomy of the distribution network park.
Multi-time Optimal Dispatch of AC-DC Hybrid Microgrid with Spatiotemporal Discrepancy
Authors: Chen Hao , Lin Yi , Guo Chuangxin
Published: December 2023

AC-DC hybrid microgrid with high permeability of renewable energy and its special system structure poses a challenge to the rational dispatch of AC-DC hybrid microgrid. To solve the problem, a multi-time period stochastic optimization of AC-DC hybrid microgrid scheduling strategy is proposed in this paper, which considers spatiotemporal differences. In the day-ahead optimal stage, the comprehensive consideration of the operating costs and characteristics of each distributional unit and bidirectional AC/DC power converter in the microgrid, a backup plan is developed to cope with the uncertainties of wind and AC/DC loads. In the intra-day scheduling stage, multi-scenario analysis technology is used to simulate the uncertainty of wind and AC and DC loads, and the intra-day rolling optimization dispatch model is constructed to ensure the validity of the day-ahead plan and fully suppress the power fluctuations caused by the day-ahead forecasting errors. Finally, by an example, the results show that the method can effectively deal with the influence of multi-uncertainties of the AC-DC hybrid microgrid.
Simulation calculation of guano fault hazardous areas in overhead transmission lines in power systems
Authors: Mao Xiaopo , Cui Qiuju , Ye Jianfeng , Li Xin , Deng Dehui , Zhou Guangyuan , Li Chaohui , Gao Liang , Yang Haibo , Yan Weiming
Published: December 2023

Guano flashover is the most typical type of bird damage fault, which can be divided into two types based on the formation mechanism: guano spatial flashover and guano pollution flashover. These two types of flashover are harmful to almost all levels of transmission lines. For 110 kV level transmission lines, guano flashover faults account for over 90% of all bird damage faults. Among them, guano space flashover has caused tripping faults in multiple foreign ultra-high voltage lines. From this, it can be seen that finding the mechanism of bird manure fault formation and formulating corresponding preventive measures are of great significance for the safe operation of transmission lines.
Research on the fault diagnosis method of AC power supply in substations based on a synchronous digital sampling technology
Authors: Fan Dehe , Li Xinhai , Wang Fan , Xiao Xing
Published: December 2023

In order to improve the accuracy and efficiency of AC power supply fault diagnosis in substations, a fault diagnosis method of AC power supply in substations based on synchronous digital sampling technology is proposed and designed in this study. Based on the IEC 61850-9-2 communication protocol, the same sampling of the status data of the substation AC power supply is realized first. Then, in order to improve the fault diagnosis effect, the data is pre-processed such as de-noising and de-redundancy. Finally, the substation AC power supply fault diagnosis is carried out based on Dempster/Shafer (D-S). The experimental results show that for different types of faults, the diagnosis accuracy of the proposed method is higher than 95.5%, and the diagnosis time is less than 1.31 ms.
A Distributed Dispatch Method for Power Distribution Networks Considering Large-scale Connected Electric Vehicles
Authors: Zheng Li , Tan Wenzhuo
Published: December 2023

The connection of large-scale electric vehicles (EVs) to power distribution networks leads to challenges such as increased peak loads and communication difficulty. To address this challenge, in this paper, a distributed dispatch method is suggested for power distribution networks that take the connection of large-scale EVs into account. First, a distributed dispatch framework is developed for the power distribution network. Subsequently, resources such as EVs, distributed photovoltaics (PVs), and micro gas turbines (MGTs) are considered to construct an optimal dispatch model, and the alternating direction multipliers method (ADMM) is applied to achieve a distributed solution. Finally, the performance of the suggested approach is tested on a modified IEEE 33-bus model.
Optimal Scheduling of New Energy and Thermal Power Combined Operation System
Authors: Zhao Duoxian , Ma Ming , Yuan Chen , Zhu Hongyi
Published: December 2023

Nowadays, the power grid with a high proportion of renewable energy is increasingly popular. Taking a new energy power system including wind power (WP), photovoltaic power (PP), and pumped storage power (PSP) as an example, in order to solve the problem of resource waste such as massive WP-PP abandonment and power losses caused by the randomness and volatility of new energy, this paper establishes a combined power generation model of WP-PP-PSP-thermal power (TP). It achieves the goal of minimum network loss and minimum WP-PP abandonment in the combined power generation system according to the characteristics of PSP and considering various constraints and distribution network reconfiguration. Then, the second-order cone relaxation (SOCR) technology is used to transform the model into a mixed second-order cone programming model. Finally, the design scheme is tested by the improved IEEE 33-bus system, and the effectiveness of the algorithm is analyzed. The results show that peak cutting and valley filling can be realized when PSP energy is added to the WP-PP grid connection system.
An acceleration and optimization method of edge computing using filter level pruning
Authors: Liao Gaofeng , He Yong , Lu Lin , Ye Guangxian , Yuan Hanjie , Jiang Tianhang , Chen Liang , Tan Haiao , Luo Jianbin , Zhang Jiawei
Published: December 2023

In order to reduce the complexity of the network and the amount of floating-point computation, this paper proposes an efficient target detection algorithm. Firstly, we use the feature of deep separable convolution to reduce the amount of calculation and design a target detection network structure. Based on the new network structure, the filter is pruned by using the size of the L1 norm value as the threshold to further compress the network model. Then it is deployed on the embedded GPU platform of the edge device for verification, and excellent algorithm performance is achieved. The combination of deep separable convolution and filter-level pruning greatly improves the computational performance of the target detection algorithm on the edge device.
Enhancement of nerve regeneration through schwann cell-mediated healing in a 3D printed polyacrylonitrile conduit incorporating hydrogel and graphene quantum dots: a study on rat sciatic nerve injury model
Authors: Hoveizi Elham
Published: December 2023

Despite recent technological advancements, effective healing from sciatic nerve damage remains inadequate. Cell-based therapies offer a promising alternative to autograft restoration for peripheral nerve injuries, and 3D printing techniques can be used to manufacture conduits with controlled diameter and size. In this study, we investigated the potential of Wharton’s jelly-derived mesenchymal stem cells (WJMSCs) differentiated into schwann cells, using a polyacrylonitrile (PAN) conduit filled with fibrin hydrogel and graphene quantum dots (GQDs) to promote nerve regeneration in a rat sciatic nerve injury model. We investigated the potential of WJMSCs, extracted from the umbilical cord, to differentiate into schwann cells and promote nerve regeneration in a rat sciatic nerve injury model. WJMSCs were 3D cultured and differentiated into schwann cells within fibrin gel for two weeks. A 3 mm defect was created in the sciatic nerve of the rat model, which was then regenerated using a conduit/fibrin, conduit covered with schwann cells in fibrin/GQDs, GQDs in fibrin, and a control group without any treatment (n = 6/group). At 10 weeks after transplantation, motor and sensory functions and histological improvement were assessed. The WJMSCs were extracted, identified, and differentiated. The differentiated cells expressed typical schwann cell markers, S100 and P75. In vivo investigations established the durability and efficacy of the conduit to resist the pressures over two months of implantation. Histological measurements showed conduit efficiency, schwann cell infiltration, and association within the fibrin gel and lumen. Rats treated with the composite hydrogel-filled PAN conduit with GQDs showed significantly higher sensorial recovery than the other groups. Histological results showed that this group had significantly more axon numbers and remyelination than others. Our findings suggest that the conduit/schwann approach has the potential to improve nerve regeneration in peripheral nerve injuries, with future therapeutic implications.
Extreme cold events in Europe under a reduced AMOC
Authors: Meccia Virna L , Simolo Claudia , Bellomo Katinka , Corti Susanna
Published: December 2023

There is a consensus that a weakened Atlantic Meridional Overturning Circulation (AMOC) decreases mean surface temperature in the Northern Hemisphere, both over the ocean and the continents. However, the impacts of a reduced AMOC on cold extreme events have not yet been examined. We analyse the impacts of a reduced AMOC strength on extreme cold events over Europe using targeted sensitivity experiments with the EC-Earth3 climate model. Starting from a fully coupled ocean-atmosphere simulation in which the AMOC was artificially reduced, a set of atmosphere-only integrations with prescribed sea surface temperature and sea-ice cover was conducted to evaluate the effects of weakly and strongly reduced AMOC strength. Despite overall cooling, reduced AMOC leads to fewer winter cold spells in Europe. We find that the weakened AMOC intensifies near-surface meridional gradient temperature in the North Atlantic and Europe, thus providing the energy to boost the jet stream. A stronger jet stream leads to less atmospheric blocking, reducing the frequency of cold spells over Europe. Although limited to the output of one model, our results indicate that a reduced AMOC strength may play a role in shaping future climate change cold spells by modulating the strength of the jet stream and the frequency of atmospheric blocking.
The discreet charm of the discrete series in dS2
Authors: Anninos Dionysios , Anous Tarek , Pethybridge Ben , Şengör Gizem
Published: December 2023

We study quantum field theories placed on a two-dimensional de Sitter spacetime (dS2) with an eye on the group-theoretic organization of single and multi-particle states. We explore the distinguished role of the discrete series unitary irreducible representation (UIR) in the Hilbert space. By employing previous attempts to realize these states in free tachyonic scalar field theories, we propose how the discrete series may contribute to the Källén–Lehmann decomposition of an interacting scalar two-point function. We also study BF gauge theories withSL(N,R)gauge group in dS2and establish a relation between the discrete series UIRs and the operator content of these theories. Although present at the level of the operators, states carrying discrete series quantum numbers are projected out of the gauge-invariant Hilbert space. This projection is reminiscent of what happens for quantum field theories coupled to semiclassical de Sitter gravity, where we must project onto the subspace of de Sitter invariant states. We discuss how to impose the diffeomorphism constraints on local field-theory operators coupled to two-dimensional gravity in de Sitter, with particular emphasis on the role of contact terms. Finally, we discuss an SYK-type model with a random two-body interaction that encodes an infinite tower of discrete series operators. We speculate on its potential microscopic connection to theSL(N,R)BF theory in the large-Nlimit.
Spider cone: a novel behavior of cobweb-like excretions of Conus geographus
Authors: De Guzman S H , Bacho H A , Cawaling L R , Taylor D , Saguil N A
Published: December 2023

Conus geographus is a specialized nocturnal cone snail that has evolved to engulf several target fish at once. A newly discovered behavior was observed wherein it releases cobweb-like excretions. This study focuses on characterizing this behavior from visual media as well as identifying the factors triggering the releases of cobweb-like excretions. Data from observations were then analyzed together with previously published C. geographus data and data from arachnids to determine similarities and their relationship between adaptation and evolution. Comparisons revealed that the first factor for releasing the cobweb-like excretions would be mobilization, which is the descending ability of C. geographus using the projections that may be similar to the abseiling spiders of Theridiidae and Araneidae. Next factor is the defense mechanism wherein the cone snail’s siphon was compared to spiders with trichobothria, which are used for mechanoreception. The last considered factor is an additional feeding strategy. In the observed visual media, the C. geographus wrapped an aerator with its excretions similar to the entangling mechanism for feeding specific species of spiders. Gathered information revealed that the cobweb-like excretions were used for mobility, defense mechanism, and feeding strategy, as C. geographus is highly susceptible to adaptation due to its neurological abilities. The compared data showed similarities between geography cone snails and spiders, suggesting a strong linkage between the two phyla that shows a convergent evolutionary relationship.
Digital and circular technologies for climate-smart and sustainable agriculture: the case of Vietnamese coffee
Authors: Nguyen Van Duy , Pham Tri Cong , Pham Thu Thuy , Phan Anh N.
Published: December 2023

This comprehensive article addresses the pressing challenges confronting the global agriculture, primarily driven by climate change and resource constraints. With a focus on promoting climate-smart and sustainable agricultural practices, the study explores the transformative potential of emerging technologies, e.g., the innovative use of digital technologies like Internet of Things, Artificial Intelligence, and Blockchain, showcasing real-world examples of their benefits, and circular technologies, e.g., waste-to-value practices. The challenges of population growth, climate change, environmental impact, and the plight of smallholder farmers are elucidated. Climate-Smart Agriculture initiatives supported by the World Bank Group demonstrate practical efforts in addressing these challenges, aligning with sustainable development goals. Here, we introduce an innovative and smart agriculture (INNSA) platform for the creation and operation of sustainable coffee value chain in Vietnam as a case of study. Thought-provoking questions for future research conclude the review, encouraging interdisciplinary collaboration. In summary, this article provides a compelling case for adopting sustainable agricultural practices through digital and circular technologies, offering a roadmap for global agriculture’s transformation and resilience in the face of climate change.
Artificial intelligence-based solutions for coffee leaf disease classification
Authors: Pham Tri Cong , Nguyen Van Duy , Le Chi Hieu , Packianather Michael , Hoang Van-Dung
Published: December 2023

Coffee is one of the most widely consumed beverages and the quantity and quality of coffee beans depend significantly on the health and condition of coffee plants, particularly their leaves. The automation of coffee leaf disease classification using AI is an essential need, providing not only economic benefits but also contributing to environmental conservation and creating better conditions for sustainable coffee cultivation. Through the application of AI, early disease detection is facilitated, thereby reducing pest and disease control costs, minimizing crop losses, increasing coffee productivity and product quality, and promoting environmental preservation. Many studies have proposed AI algorithms for coffee disease classification. However, numerous algorithms employ classical algorithms, while some utilize deep learning, the current state-of-the-art in computer vision. The challenge lies in the fact that when using deep learning, a substantial amount of data is required for training. The design of deep learning architectures to enhance model accuracy while still working with a small training dataset remains an area of ongoing research. In this study, we propose deep learning-based method for coffee leaf disease classification. We propose the combination of different deep convolutional neural networks to further improve overall classification performance. Early and late fusion have been conducted to evaluate the effectiveness of the pre-trained model. Our experimental results demonstrate that the ensemble method outperforms single-model approaches, achieving high accuracy and precision in BRACOL coffee disease leaf.
Applying 10 MeV e-Beam Irradiation to Improve the Microbiological Quality of Dried Anchovy Products
Authors: Thanh Thao Pham Thi , Minh Tuan Hoang Sy
Published: December 2023

This study evaluates the efficacy of e-beam irradiation in anchovy drying from an initial moisture content of 78 ± 1% wb to 20 ± 1% wb. The anchovy was irradiated with a 10 MeV energy level and doses ranging from 3 to 7 kGy, with air temperatures of around 30°C. Microbial quality was assessed at the Intertek laboratory before and after irradiation. Results showed that parameters such as Clostridium perfringens, Coliforms, E. coli, Salmonella spp., Staphylococcus aureus, Vibrio parahaemolyticus Bacteria, Yeasts and Moulds, and TPC (30°C) met the expected results at a dose of 7 kGy, demonstrating the quality of anchovy products for export. This study highlights the potential of e-beam irradiation in the inactivation of pathogenic microorganisms without compromising food quality in anchovy products.
Species composition of macromolluscs in Barangay Talao-talao, Lucena, Quezon province, Philippines
Authors: Bernabe J R , Acebron K J B , Tejamo C V , Aggabao M J D , Bantigue P C , Guinto A , Caril A , Saguil N A
Published: December 2023

Degradation of upland vegetation and the continuous environmental insults on coastal ecosystems negatively impact the inhabiting molluscs. In particular, macromolluscs present in the intertidal zones of coastal communities in the Philippines are directly affected by human activities and the fast-changing climate. However, a limited number of studies have investigated the effects of habitat alteration and degradation on the composition and diversity of the Philippines’ intertidal molluscs. Thus, this study assessed the species composition of macromolluscs in Lucena, Quezon, and the underlying environmental and habitat factors that may dictate the presence and abundance of these marine animals. To address these concerns, handpicking and purposive sampling of marine molluscs were conducted in the entire intertidal region of the sampling site. This study reported 62 different species at the intertidal zones of Lucena, Quezon, with species originating from the family Olividae being the most abundant organism among the sampled gastropod and bivalve species in the area. Analysis of the observational differences in molluscan habitat may highlight ecological factors affecting the diversity and abundance of the intertidal fauna. Continuous use of the shoreline for traditional fishing and the close proximity of the port of Lucena and human habitation to the coastal zone may also serve as underlying factors to the lack of live mollusc samples in the intertidal region nearest to the port. Together, these findings suggest a high species composition and abundance of macromolluscs inhabiting the intertidal zone of Lucena, Quezon, highlighting the drastic effects of changing marine ecosystems on the ability of various species to occupy a specific area in the marine environment.
Optimization of microwave-assisted heat pump drying parameters of Vietnamese black tiger shrimp using the response surface methodology
Authors: Le Nhu-Chinh , Tran Thi-Bao-Tien
Published: December 2023

This article uses response surface methodology (RSM) to optimize the microwave drying process of black tiger shrimp to ensure drying time is shortened, energy consumption is reduced, and product quality is better. Therefore, the study’s primary objectives were defined as drying time, rehydration rate, and energy consumption. The main optimal parameters affecting the above goals were air temperature (20 ÷ 40) °C, air velocity (1÷2) m/s, and microwave power (100 ÷ 500) W. The research results show that the optimal drying conditions for the best quality of dried black tiger shrimp and the highest drying productivity are a drying temperature t of 34.74 °C, a drying airspeed V of 1.87 m/s, a microwave power MW of 135.78 W and a humidity relative humidity of (15 ÷ 17)% with characterized by maximum desirability function (0.993). Furthermore, the experimental results demonstrate the completed product values with a drying time of 13.7 minutes, a rehydration ratio 2.33, and a specific energy consumption of 3.23 kWh/kgH2O. This study would contribute to developing technical capabilities for designing microwave-assisted heat pump dryers applicable to such high-valued foodstuffs.
Assessment of dissimilar friction stir welded AA6061/SS316 for sustainable industry
Authors: Ho Huy Huu , Nguyen Quan Minh , Duong Hao Dinh , Tran Tra Hung
Published: December 2023

Energy and environmental issues have played an important role in developing sustainable industries. The incorporation of lightweight materials into various structures enables a reduction in both weight and fuel consumption, resulting in saving energy. So, the selection of material and joining techniques have contributed significantly in these problems. This paper focused on the assessment of dissimilar lap-joint between AA6061 to SS316 using green technology as friction stir welding. The effect of welding parameters on the properties of joints was assessed. The test results showed that the welding interface is sensitive to rotational speed. The joint with the highest strength is approximately 6200 N at 700 rpm. In this case, the joint was fractured in heat effected zone on the aluminum side. The welding interface was revealed by using scanning electron microscope and energy-dispersive X-ray spectroscopy images to analyze the joint quality.
Estimation of the required power of bow thruster based on numerical simulation
Authors: Danh Bui Thanh , Mai Linh Hoang Thi , Hai Ha Nguyen Thi
Published: December 2023

The paper presents the results of hydrodynamic characteristics of bow thruster (thrust coefficient K

T
, torque coefficient K

Q
) in various pitch angles using RANSE method and compared to the experiment data provided by Maritime Advanced Research Centre (CTO S.A.), Gdansk, Poland. The required power of the bow thruster is estimated based on those numerical simulations. To get a better energy efficiency, the thrust-to-power ratio with pitch angle can be compared. The simulation of a rotating propeller is done using the sliding mesh approach. The k-epsilon turbulence model is utilized with commercial code ANSYS CFX when analyzing bow thruster performance. The results show that the difference between numerical and experiment results is quite high. Moreover, the power and the thrust-to-power ratio increase with the pitch angles and the bow thruster performs the best efficiency at the pitch angle of around 19°.
Effects of material strain rate, impulse profile on damage evolution of steel plates subjected to repeated pressures
Authors: Huynh V-V , Dang X-P , Quach H N , Le N A V , Le C L , Truong D D
Published: December 2023

This study deals with a numerical estimation of the damage evolution of steel plates used in ships and offshore structures due to repeated slamming-induced pressures. The numerical analysis model was developed using finite element ABAQUS software. Subsequently, the validated model was extended to investigate the effects of material strain rate and impulse profile on the damage evolution of plates having actual scantlings. Different strain rate models were used, and several types of impulse profiles that can be used to simplify the actual slamming pressure were adopted. In the simulation, the material strain hardening was defined for the plate model, and the impulsive pressures were applied uniformly over the plate while it was fully clamped at four edges. The results showed that a large effect of the material strain rate on the damage evolution of the plate was noticed for only several first impacts, while the effect of the impulse profile is remarkable for whole impact events. The occurrence of the pseudo-shakedown phenomenon of steel plates was examined accordingly. The results can be useful for the design of ships and offshore structures against slamming.