bluuebunny/crossref_metadata_2025 huggingface dataset:
Statics and dynamics of an underwater electrostatic curved electrode actuator with rough surfaces
Authors: Lake-Speers Melinda A , Preetham Burugupally Sindhu , Hoelzle David J
Published: September 2023

Here, we present a model, design, static and dynamic testing, and analysis of an electrostatic curved electrode actuator in deionized water. The actuator is integrated within a microfluidic device designed for high throughput cell sorting. The actuator shifts the bifurcation point of a Y-shaped microfluidic channel to simultaneously increase the width of one channel while decreasing the width of another channel, thus changing the bias in hydrodynamic resistance between outlet channels. The actuator is modeled as a clamped-roller beam and the static displacement is calculated based on Rayleigh–Ritz energy methods. The model accounts for oxide growth and surface roughness that occurs during fabrication. We observe that modeling a rough contact surface improves the maximum displacement prediction to within less than 20% error from the experimental value. Additionally, the model predicts a release voltage within less than 8% error of the experimental value. We also present dynamic experiments to test the actuator displacement at frequencies from 1 to 4096 Hz and show that the actuator achieves large displacements (

>

8 µm) at high frequencies (

>

100 Hz).
Dual-wavelength dielectric metasurface for full-space light manipulations
Authors: Li Hualin , Yue Wenjing , Gao Song
Published: September 2023

Dielectric metasurfaces have been credited for their salient capability in manipulating visible light with high efficiency, yet their operations are usually specified to the transmission space with limited functionality at a specified single wavelength. In this work, we show that dielectric metasurface can also be considered as an effective platform to independently control transmitted and reflected light wavefronts with high efficiency at two distinct wavelengths. In specific, silicon meta-atoms allowing high transmission and reflection of orthogonally linear-polarized light at wavelengths of 690 nm and 750 nm along with independent 2π phase modulations are successfully established. The first demonstrated dual-functional metasurface can transform incident plane wave into focused point beam spot and focused vortex beam in transmission and reflection spaces, respectively. The spatial multiplexing strategy is further considered to enrich the functionality diversity of a single meta-device, on which two off-axis light focusing phenomena and focused vortex beams carrying opposite topological charges in either transmission or reflection spaces with reduced crosstalk are successfully witnessed. Lastly, the metasurface enabling broadband anomalous deflection further demonstrates that the device’s efficiency can be further improved with densely packed meta-atoms. Our study provides a new thought in light control, which can be further considered in the development of multi-wavelength and full-space meta-devices.
Predicting mechanical properties of CO2 hydrates: machine learning insights from molecular dynamics simulations
Authors: Zhang Yu , Song Zixuan , Lin Yanwen , Shi Qiao , Hao Yongchao , Fu Yuequn , Wu Jianyang , Zhang Zhisen
Published: September 2023

Understanding the mechanical properties of CO2 hydrate is crucial for its diverse sustainable applications such as CO2 geostorage and natural gas hydrate mining. In this work, classic molecular dynamics (MD) simulations are employed to explore the mechanical characteristics of CO2 hydrate with varying occupancy rates and occupancy distributions of guest molecules. It is revealed that the mechanical properties, including maximum stress, critical strain, and Young’s modulus, are not only affected by the cage occupancy rate in both large 51262 and small 512 cages, but also by the distribution of guest molecules within the cages. Specifically, the presence of vacancies in the 51262 large cages significantly impacts the overall mechanical stability compared to 512 small cages. Furthermore, four distinct machine learning (ML) models trained using MD results are developed to predict the mechanical properties of CO2 hydrate with different cage occupancy rates and cage occupancy distributions. Through analyzing ML results, as-developed ML models highlight the importance of the distribution of guest molecules within the cages, as crucial contributor to the overall mechanical stability of CO2 hydrate. This study contributes new knowledge to the field by providing insights into the mechanical properties of CO2 hydrates and their dependence on cage occupancy rates and cage occupancy distributions. The findings have implications for the sustainable applications of CO2 hydrate, and as-developed ML models offer a practical framework for predicting the mechanical properties of CO2 hydrate in different scenarios.
Applicability of ‘Toolkit for Safety Assessment’ tool to interventional radiology using probabilistic risk assessment techniques
Authors: Raso A L , Lopes R , Leyton F , Neves E , Ribeiro E J , Vasconcelos V , Nogueira M S
Published: September 2023

Interventional radiology brings extensive benefits to patients. Nevertheless, certain procedures may result in high doses of radiation, leading to health risks to occupationally exposed individuals (OEIs). Therefore, a more comprehensive risk analysis is essential to ensuring safety and minimising radiation exposures for all OEIs. The Toolkit for Safety Assessment (TOKSA) tool performs risk assessments based on the concepts described in ‘General Safety Requirements’ Part 3 (Radiation Protection and Safety of Radiation Sources: International Basic Safety Standards) and Part 4 (Safety Assessment for Facilities and Activities). This tool was developed based on the ‘Ibero-American Forum of Radiological and Nuclear Regulatory Agencies’ risk models and can promote the use of the risk assessment processes by OEIs. The aim of this study was to experimentally analyse the applicability of the TOKSA tool in interventional radiology with the use/support of probabilistic risk assessment techniques. The results were used to reduce the risks associated with a hemodynamics room in a hospital in Belo Horizonte, Brazil.
An SVD-based turntable calibration method with multiple reference planes segmented from point clouds
Authors: Yang Bo , Wang Zhengtuo , Xu Yuetong , Hu Songyu , Fu Jianzhong
Published: September 2023

Turntables play an essential role in various industrial areas due to their ability to improve the degree of freedom of workpieces or tools. In applications where positional accuracy of the objects is required, the accuracy of the system parameters of the turntable is critical for the applications to work properly. This paper proposes a new approach to calibrating the turntable system. First, we propose an optimized RANSAC (random sample consensus) algorithm to obtain high-accuracy reference planes from multiple frames of point clouds grabbed from the reference object placed on a turntable. Second, an singular value decomposition-based two-step method is proposed to calculate the rotation axis vector and the center position of the turntable based on the reference planes extracted by the modified RANSAC algorithm. Finally, several experiments are performed to verify the proposed methods. Compared with the existing methods, our approach gets the analytical results and tries to correct the rotation angles. The experimental results show that the proposed method considerably improves calibration accuracy and efficiency without complex devices.
A Gaussian–Pearson type VII adaptive mixture distribution-based outlier-robust Kalman filter
Authors: Wang Ke , Wu Panlong , Li Xingxiu , Xie Wenhan , He Shan
Published: September 2023

Considering that existing robust filtering algorithms rely on the selection of initial values of degree of freedom (DOF) parameters in outlier interference environments and cannot effectively cope with unknown non-stationary heavy-tailed measurement noises (HMN), a Gaussian–Pearson type VII (PTV) adaptive mixture distribution-based outlier-robust Kalman filter (GPTVMAKF) is proposed. In order to determine whether the current measurement is a normal value or an outlier, a judgment factor subject to the Beta-Bernoulli distribution is introduced. PTV distribution is used to model HMN caused by outliers, and two Gamma distributions are used to model the two different DOF parameters, which can make the PTV distribution have the adaptive adjustment ability. By introducing the inverse Wishart distribution as the prior distribution of the measurement noise covariance, which is adaptively estimated to cope with the unknown time-varying measurement noises. The state and parameters are jointly estimated by variational Bayesian. Finally, the simulation experiments verify that the proposed GPTVMAKF can obtain more accurate state estimation than existing filters in the environments with varying degrees of HMN and unknown non-stationary HMN.
Fault diagnosis of coal mills based on a dynamic model and deep belief network
Authors: Weiming Yin , Yefa Hu , Guoping Ding , Kai Yang , Xuefei Chen , Xifei Cao
Published: September 2023

As the significant ancillary equipment of coal-fired power plants, coal mills are the key to ensuring the steady operation of boilers. In this study, a fault diagnosis model was proposed on the basis of a dynamic model of a coal mill and deep belief network (DBN). First, a dynamic coal mill model that considered the joint influence of drying, ventilation and grinding forces was established. Parameters in the model were identified by designing a two-phase optimization method based on the genetic algorithm. Then, this model was used for simulating the common faults of coal mills under a variety of operating conditions and obtaining extensive data. On this basis, the DBN fault diagnosis model was established and the combination of parameters was optimized by use of an orthogonal experiment. Finally, the validity of the model was verified by using the actual operation data of the coal mill. Compared with the dynamic models built in previous studies, that constructed in this paper can significantly improve the capability to simulate and analyze the coal mill. The convergence rate of the designed two-phase optimization method was improved. The experimental results show that the proposed method of coal mill fault diagnosis based on the dynamic model and DBN has an accuracy of 95%, which proves that this method has excellent application potential.
Spatially resolved chemiluminescence imaging of multiple combustion species using a single high-speed camera
Authors: James Ashley M , Agrawal Ajay K
Published: September 2023

Simultaneous chemiluminescence (CL) imaging of multiple chemical species in unsteady and/or turbulent combustion environments requires multiple high-speed camera/intensifier systems which can be cost prohibitive. This study presents a novel optical configuration for simultaneous, spatially resolved CL imaging of two species using a single high-speed camera. The superiority of the technique over existing approaches is demonstrated via a series of experiments in a methane fueled McKenna burner operated at steady and unsteady conditions. Results demonstrate capabilities of the present system to provide spatially resolved measurements of hydroxyl (OH*) and methylidyne (CH*) species without parallax or path length errors in different flame configurations.
In situ construction of N-doped Ti3C2T
x
confined worm-like Fe2O3 nanoparticles by Fe–O–Ti bonding for LIBs anode with superior cycle performance
Authors: Jiang Wei , Zhang Zhen , Yang Kai , Zhou Jun , Hu Changjian , Pan Limei , Li Qian , Yang Jian
Published: September 2023

The development of Fe2O3 as lithium-ion batteries (LIBs) anode is greatly restricted by its poor electronic conductivity and structural stability. To solve these issues, this work presents in situ construction of three-dimensional crumpled Fe2O3@N-Ti3C2T
x
composite by solvothermal-freeze-drying process, in which wormlike Fe2O3 nanoparticles (10–50 nm) in situ nucleated and grew on the surface of N-doped Ti3C2T
x
nanosheets with Fe–O–Ti bonding. As a conductive matrix, N-doping endows Ti3C2T
x
with more active sites and higher electron transfer efficiency. Meanwhile, Fe–O–Ti bonding enhances the stability of the Fe2O3/N-Ti3C2T
x
interface and also acts as a pathway for electron transmission. With a large specific surface area (114.72 m2 g−1), the three-dimensional crumpled structure of Fe2O3@N-Ti3C2T
x
facilitates the charge diffusion kinetics and enables easier exposure of the active sites. Consequently, Fe2O3@N-Ti3C2T
x
composite exhibits outstanding electrochemical performance as anode for LIBs, a reversible capacity of 870.2 mAh g−1 after 500 cycles at 0.5 A g−1, 1129 mAh g−1 after 280 cycles at 0.2 A g−1 and 777.6 mAh g−1 after 330 cycles at 1 A g−1.
A pedagogical approach to wavelength division multiplexing measurements using 3D printing and Arduino
Authors: Rana Ankush , Bhatnagar Shivansh , Garg Sagar , Garg Amit
Published: September 2023

We have successfully performed wavelength division multiplexing (WDM) measurements using traditional as well as innovative approaches. The results obtained are accurate and precise. Both the approaches add to the conceptual understanding of WDM for the students. The innovative approach allows students to develop the WDM experimental setup at a very low cost by using the Arduino Board. It reduces the hardware dependence of the costly instruments like function generators as well as digital storage oscilloscope besides facilitating the carrying out of experiment using RGB LED and single optical fibre. It can be used as a good classroom demonstration to explain this difficult concept. The 3D design and printing of connectors for the RGB LED, and the optical rod has made the system very robust as one can easily couple, multiplex and demultiplex the optical signals. It is to the best of our knowledge that these studies have not been reported earlier.
The impact of additive manufacturing on teaching the Archimedes experiment
Authors: Kastrati Labinot , Uka Burim , Jakupi Kaltrine , Hodolli Gezim
Published: September 2023

This study aimed to investigate the effectiveness of additive manufacturing (AM)-based teaching methods compared to traditional methods for teaching the Archimedes experiment in science education. Results showed that the AM method was significantly more effective in enhancing students’ understanding of the Archimedes principle and their ability to apply it to real world scenarios. The customisable and hands on nature of 3D printing also led to higher levels of student engagement and enjoyment. However, limitations were identified in terms of the time, resources, and cost required to set up the 3D printing experiment. Despite these limitations, our study suggests that AM has the potential to revolutionise science education by providing students with a more engaging, hands on, and customisable learning experience.
TransQA: deep hybrid transformer network for measurement-guided volumetric dose prediction of pre-treatment patient-specific quality assurance
Authors: Zeng Lingpeng , Zhang Minghui , Zhang Yun , Zou Zhongsheng , Guan Yu , Huang Bin , Yu Xiuwen , Ding Shenggou , Liu Qiegen , Gong Changfei
Published: September 2023

Objective. Performing pre-treatment patient-specific quality assurance (prePSQA) is considered an essential, time-consuming, and resource-intensive task for volumetric modulated arc radiotherapy (VMAT) which confirms the dose accuracy and ensure patient safety. Most current machine learning and deep learning approaches stack excessive convolutional/pooling operations (CPs) to predict prePSQA with two-dimensional or one-dimensional information input. However, these models generally present limitations in explicitly modeling long-range dependency for volumetric dose prediction due to the loss of spatial dose features and the inherent locality of CPs. The purpose of this work is to construct a deep hybrid network by combining the self-attention mechanism-based Transformer with modified U-Net for predicting measurement-guided volumetric dose (MDose) of prePSQA. Approach. The enrolled 307 cancer patients underwent VMAT were randomly divided into 246 and 61 cases for training and testing the model. The input data included computed tomography images, radiotherapy dose images exported from the treatment planning system, as well as the MDose distribution from the verification system. The output was the predicted high-quality voxel-wise prePSQA dose distribution. Main results: qualitative and quantitative experimental results show that the proposed prediction method could achieve comparable or better performance on MDose prediction over other approaches in terms of spatial dose distribution, dose–volume histogram metrics, gamma passing rates, mean absolute error, root mean square error, and structural similarity. Significance. The preliminary results on multiple cancer sites show that our approach can be taken as a clinical guidance tool and help medical physicists to reduce the measurement work of prePSQA.
Ring artifacts correction for computed tomography image using unsupervised contrastive learning
Authors: Wang Tangsheng , Liu Xuan , Zhang Chulong , He Yutong , Chan Yinping , Xie Yaoqin , Liang Xiaokun
Published: September 2023

Objective. Computed tomography (CT) is a widely employed imaging technology for disease detection. However, CT images often suffer from ring artifacts, which may result from hardware defects and other factors. These artifacts compromise image quality and impede diagnosis. To address this challenge, we propose a novel method based on dual contrast learning image style transformation network model (DCLGAN) that effectively eliminates ring artifacts from CT images while preserving texture details. Approach. Our method involves simulating ring artifacts on real CT data to generate the uncorrected CT (uCT) data and transforming them into strip artifacts. Subsequently, the DCLGAN synthetic network is applied in the polar coordinate system to remove the strip artifacts and generate a synthetic CT (sCT). We compare the uCT and sCT images to obtain a residual image, which is then filtered to extract the strip artifacts. An inverse polar transformation is performed to obtain the ring artifacts, which are subtracted from the original CT image to produce a corrected image. Main results. To validate the effectiveness of our approach, we tested it using real CT data, simulated data, and cone beam computed tomography images of the patient’s brain. The corrected CT images showed a reduction in mean absolute error by 12.36 Hounsfield units (HU), a decrease in root mean square error by 18.94 HU, an increase in peak signal-to-noise ratio by 3.53 decibels (dB), and an improvement in structural similarity index by 9.24%. Significance. These results demonstrate the efficacy of our method in eliminating ring artifacts and preserving image details, making it a valuable tool for CT imaging.
MISHEMT intrinsic voltage gain under multiple channel output characteristics
Authors: Canales Bruno Godoy , Perina Welder Fernandes , Martino Joao Antonio , Simoen Eddy , Peralagu Uthayasankaran , Collaert Nadine , Der Agopian Paula Ghedini
Published: September 2023

In this paper the MISHEMT device (metal/Si3N4/AlGaN/AlN/GaN - metal–insulator–semiconductor high electron mobility transistor) is studied focusing mainly on the impact of the multiple conductions on the intrinsic voltage gain (A
v). It is shown that the total drain current is composed of three different drain current components, whereof one is related to the MIS channel and the other two are related to high electron mobility transistor (HEMT) channels. The device output characteristics present double drain voltage saturation that gives rise to a double plateau in the saturation region of the output characteristics. This behavior relies also on the gate voltage, so the output characteristics and analog parameters extraction are bias dependent. The intrinsic voltage gain increases thanks to the early voltage increment in the second plateau where HEMT conduction is dominant. Electron concentration profiles were simulated in order to investigate the device saturation regime.
Development of the first Tesla class iron-based superconducting coil for high field application
Authors: Ding Hangwei , Zhao Hang , Huang Pengcheng , Yu Lei , Xu Jianyuan , Fang Zhen , Chen Zhiyou , Wang Dongliang , Zhang Xianping , Chen Wenge , Ma Yanwei
Published: September 2023

This study has, for the first time, combined iron-based superconductor (IBS) with high field insert coil technology to generate a higher magnetic field. Nine large-sized iron-based superconducting double pancake coils (DPCs) were fabricated, and their performance was evaluated at 4.2 K. Subsequently, seven DPCs with superior performance were assembled to form an IBS insert coil and tested at the 20 T background field. The test results indicated that the insert coil successfully generated above 1 T magnetic field under the 0 T, 10 T, and even 20 T background field, respectively. Notably, the poorest IBS DPC still had a critical current of about 84 A at the background field of 20 T, which outperformed all previously reported performance tests of IBS coils. This paper provides a detail introduction to the design and fabrication process of the IBS insert coil, presents the test results, and discusses them.
Numerical investigation of heat and mass transfer of the Sisko fluid in a wire-coating process with variable fluid properties
Authors: Srikantha N , Hegde Soniya
Published: September 2023

The fundamental and essential objective of the wire coating process is to reduce the shear stress and extraction force exerted on the wire from the die in order to achieve practical benefits. Therefore, the purpose of the present work is to develop a mathematical model for the wire coating process withdrawal of the wire from the die. The Sisko fluid model and the temperature-dependent thermophysical properties are taken into consideration for modelling the constitutive equation. The basic equations governing the flow are solved with the aid of the numerical method. The impact of key factors is scrutinized. The influence of shear stress on the surface of the wire and fluid flow rate are delineated. The linear regression model is formulated to explore the significance of the relationship between the amount of force required to pull the wire and flow control variables. Moreover, the heat transfer rate and shear stress rate of molten polymer are modeled using quadratic correlation models obtained through the Central Composite Design (CCD) technique. To simultaneously achieve maximum heat transfer rate and minimum shear stress rate for the melt, the ideal values of the variable viscosity parameter, Sisko fluid parameter, and Brinkman number are determined. The study reveals that the required result occurs for a low level of the variable viscosity parameter, Sisko fluid parameter, and the Brinkman number. Additionally, a sensitivity analysis has been performed. The result reveals that the shear stress rate and heat transfer rate exhibit the highest sensitivity to variations in the viscosity parameter.
The low temperature liquid metal pressure sensors
Authors: Zhou Xiao-Ping , Chen Ping
Published: September 2023

Pressure measurement of geotechnical constructions subjected to low temperature plays significant roles in the safety and stability of geotechnical engineering activities. However, the research of pressure sensors in low temperature environment is lacked. In this work, a Galinstan liquid metal pressure sensor under low temperature condition is developed to detect pressure in geotechnical engineering. The elastomer PDMS (polydimethylsiloxane) is employed as the base material. Micro-channels are carved using microfluidic soft lithography technology. The liquid metal is filled as a conductor, and a spring steel case is used for encapsulation. The theoretical relationship between the resistance and pressure is derived, and the theoretical resistance values are compared with experimental resistance values to verify the accuracy of theoretical derivations. The key performance indexes of the designed sensor, such as the compliance, repeatability and hysteresis, are experimentally investigated. The numerical results show that the applied pressure can be uniformly transmitted to the internal PDMS chip with the help of the liquid buffer layer. The experimental results imply that this developed sensor with liquid buffer layer has high curve compliance, good repeatability and low hysteresis in low temperature environment, which provides effective tools for the pressure monitoring of geotechnical constructions subjected to low temperature.
Surface structured silver-copper bimetallic nanoparticles by irradiation of excimer laser pulses to bilayer thin films
Authors: Naranji Elham , Aliannezhadi Maryam , Panahibakhsh Somayeh
Published: September 2023

Optical chips based on plasmonic bimetal nanoparticles are of particular interest for various applications, including optical sensors, as well as plasmon-enhanced fluorescence and plasmon-enhanced Raman scattering due to their extraordinary optical properties. In the paper, the formation of the bimetallic nanoparticles on the BK7 substrate and tuning of the LSPR wavelengths by irradiation of excimer laser pulses (193 nm output wavelength and 15 ns temporal pulse linewidth) to silver-copper thin films deposited by the physical vapor deposition (PVD) method is studied. Applying four and five ArF laser pulses with the fluence of 140 mJ cm−2 leads to the formation of spherical Ag-Cu nanoparticles and clusters, respectively, with several LSPR peaks in the UV and visible ranges. Also, sharp and intense LSPR peaks in the 560 to 700 nm spectral range are observed in the absorption spectra of the produced samples with four laser pulses which indicates the ability of the method for tuning the LSPR wavelength. Furthermore, the highest enhancement in the Raman scattering of R6G solution is provided using this sample as a substrate for Raman spectroscopy. Therefore, the laser-produced spherical Ag-Cu NPs by these parameters of laser irradiation can be a good candidate for applications based on LSPR, and Raman or fluorescence enhancement.
Quantum coherence resourced by the strong nuclear quadrupolar interaction
Authors: Çakmak Selçuk , Gençten Azmi , Altintas Ferdi
Published: September 2023

We propose a setup for studying the quantum coherence properties of a quadrupolar nucleus using the nuclear magnetic resonance platforms We consider powder samples labeled with 23Na and oriented with respect to the static magnetic field. By using the l
1-norm of coherence, we examine the quantum coherence in the Zeeman basis at thermal equilibrium. Non-zero coherence is found to result from the strong nuclear quadrupolar spin interactions. It is also shown that higher coherence is created as the quadrupolar interaction coefficient increases. We also discuss the stability of coherence in a possible measurement process in order to use it as a potential resource in any quantum computation protocol.
Effects of confining pressure and pore pressure on multipole borehole acoustic field in fluid-saturated porous media
Authors: Zhao 赵 Zhi-Qiang 志强 , Liu 刘 Jin-Xia 金霞 , Liu 刘 Jian-Yu 建宇 , Cui 崔 Zhi-Wen 志文
Published: September 2023

In-situ stress is a common stress in the exploration and development of oil reservoirs. Therefore, it is of great significance to study the propagation characteristics of borehole acoustic waves in fluid-saturated porous media under stress. Based on the acoustoelastic theory of fluid-saturated porous media, the field equation of fluid-saturated porous media under the conditions of confining pressure and pore pressure and the acoustic field formula of multipole source excitation in open hole are given. The influences of pore pressure and confining pressure on guided waves of multipole borehole acoustic field in fluid-saturated porous media are investigated. The numerical results show that the phase velocity and excitation intensity of guided wave increase significantly under the confining pressure. For a given confining pressure, the phase velocity of the guided wave decreases with pore pressure increasing. The excitation intensity of guided wave increases at low frequency and then decreases at high frequency with pore pressure increasing, except for that of Stoneley wave which decreases in the whole frequency range. These results will help us get an insight into the influences of confining pressure and pore pressure on the acoustic field of multipole source in borehole around fluid-saturated porous media.
Characteristic analysis of 5D symmetric Hamiltonian conservative hyperchaotic system with hidden multiple stability
Authors: Huang 黄 Li-Lian 丽莲 , Ma 马 Yan-Hao 衍昊 , Li 李 Chuang 创
Published: September 2023

Conservative chaotic systems have unique advantages over dissipative chaotic systems in the fields of secure communication and pseudo-random number generator because they do not have attractors but possess good traversal and pseudo-randomness. In this work, a novel five-dimensional (5D) Hamiltonian conservative hyperchaotic system is proposed based on the 5D Euler equation. The proposed system can have different types of coordinate transformations and time reversal symmetries. In this work, Hamilton energy and Casimir energy are analyzed firstly, and it is proved that the new system satisfies Hamilton energy conservation and can generate chaos. Then, the complex dynamic characteristics of the system are demonstrated and the conservatism and chaos characteristics of the system are verified through the correlation analysis methods such as phase diagram, equilibrium point, Lyapunov exponent, bifurcation diagram, and SE complexity. In addition, a detailed analysis of the multistable characteristics of the system reveals that many energy-related coexisting orbits exist. Based on the infinite number of center-type and saddle-type equilibrium points, the dynamic characteristics of the hidden multistability of the system are revealed. Then, the National Institute of Standards and Technology (NIST) test of the new system shows that the chaotic sequence generated by the system has strong pseudo-random. Finally, the circuit simulation and hardware circuit experiment of the system are carried out with Multisim simulation software and digital signal processor (DSP) respectively. The experimental results confirm that the new system has good ergodicity and realizability.
Distributed Control Software for the Active Surface System of Tian-ma Radio Telescope
Authors: Zhang Dong , Zhao Rong-Bing , Yan Zhen , Shang-Guan Wei-Hua , Ye Qian , Shen Zhi-Qiang , Liu Qing-Hui , Wang Jin-Qing , Fu Li , Zhang Chu-Yuan , Song Dong-Fang , Liu Si-Yu
Published: September 2023

The Tian-ma Radio Telescope (TMRT) applies an Active Surface System (ASFS), which corrects for large-scale deformations due to gravity and thermal on the primary reflector. The centralized and automated management of the ASFS using software has become a challenge, for which we have developed the TMRT Active Surface System Control Software (TASCS). This paper describes the design and implementation of TASCS for device control, status monitoring, human-computer interaction, and data management functionalities. TASCS adopts the open-source Tango Controls framework and distributes middleware technology to realize real-time automated adjustment of the primary reflector through remote centralized control of a large number of actuators. At present, it has been successfully deployed on the TMRT and has played an important role in Event Horizon Telescope observations.
Feather-inspired flow control device across flight regimes
Authors: Othman Ahmed K , Nair Nirmal J , Goza Andres , Wissa Aimy
Published: September 2023

Bio-inspired flow control strategies can provide a new paradigm of efficiency and adaptability to overcome the operational limitations of traditional flow control. This is particularly useful to small-scale uncrewed aerial vehicles since their mission requirements are rapidly expanding, but they are still limited in terms of agility and adaptability when compared to their biological counterparts, birds. One of the flow control strategies that birds implement is the deployment of covert feathers. In this study, we investigate the performance characteristics and flow physics of torsionally hinged covert-inspired flaps mounted on the suction side of a NACA2414 airfoil across different Reynolds numbers, specifically 200,000 and 1,000. These two Reynolds numbers are representative of different avian flight regimes where covert feathers have been observed to deploy during flight, namely cruising and landing/perching. We performed experiments and simulations where we varied the flap location, the hinge stiffness, and the moment of inertia of the flap to investigate the aerodynamic performance and describe the effects of the structural parameters of the flap on the aerodynamic lift improvements. Results of the study show up to 12% lift improvement post-stall for the flapped cases when compared to the flap-less baseline. The post-stall lift improvement is sensitive to the flap’s structural properties and location. For instance, the hinge stiffness controls the mean deflection angle of the flap, which governs the resulting time-averaged lift improvements. The flap moment of inertia, on the other hand, controls the flap dynamics, which in turn controls the flap’s lift-enhancing mechanism and how the flap affects the instantaneous lift. By examining the time-averaged and instantaneous lift measurement, we uncover the mechanisms by which the covert-inspired flap improves lift and highlights similarities and differences across Reynolds numbers. This article highlights the feasibility of using covert-inspired flaps as flow control across different flight missions and speeds.
Biomimetic intruder tip design for horizontal penetration into a granular pile
Authors: Sandeep C S , Evans T Matthew
Published: September 2023

In nature, woodpeckers peck trees with no reported brain injury. A highly functional system comprising a hyoid bone, smooth skull, straight pointed beak with varying lengths of upper and lower beak bones, and rhamphotheca is one of the adaptations that enable efficient pecking. Soil penetration is an energy-intensive procedure used in civil infrastructure applications and is often followed by pushing, impact driving, and digging. This study uses discrete element modeling to evaluate the effect of woodpecker beak mimetic intruder tip design with wedge offsets on lift and drag forces during horizontal penetration into granular piles. The findings show that the wedge offsets of the intruder have a negligible effect on drag forces. By contrast, lift forces can be manipulated by adjusting the top and bottom offsets of the intruder, which can be used to guide the intruder upward, downwards, or horizontally. Furthermore, as the width of the intruder increased, the lift and drag forces also increased.
Fish-inspired robotic algorithm: mimicking behaviour and communication of schooling fish
Authors: Connor Jack , Joordens Matthew , Champion Benjamin
Published: September 2023

This study aims to present a novel flocking algorithm for robotic fish that will aid the study of fish in their natural environment. The algorithm, fish-inspired robotic algorithm (FIRA), amalgamates the standard flocking behaviors of attraction, alignment, and repulsion, together with predator avoidance, foraging, general obstacle avoidance, and wandering. The novelty of the FIRA algorithm is the combination of predictive elements to counteract processing delays from sensors and the addition of memory. Furthermore, FIRA is specifically designed to work with an indirect communication method that leads to superior performance in collision avoidance, exploration, foraging, and the emergence of realistic behaviors. By leveraging a high-latency, non-guaranteed communication methodology inspired by stigmergy methods inherent in nature, FIRA successfully addresses some of the obstacles associated with underwater communication. This breakthrough enables the realization of inexpensive, multi-agent swarms while concurrently harnessing the advantages of tetherless communication. FIRA provides a computational light control algorithm for further research with low-cost, low-computing agents. Eventually, FIRA will be used to assimilate robots into a school of biological fish, to study or influence the school. This study endeavors to demonstrate the effectiveness of FIRA by simulating it using a digital twin of a bio-inspired robotic fish. The simulation incorporates the robot’s motion and sensors in a realistic, real-time environment with the algorithm used to direct the movements of individual agents. The performance of FIRA was tested against other collective flocking algorithms to determine its effectiveness. From the experiments, it was determined that FIRA outperformed the other algorithms in both collision avoidance and exploration. These experiments establish FIRA as a viable flocking algorithm to mimic fish behavior in robotics.
Rayleigh–Bénard convection in mono and hybrid nanoliquids in an inclined slot
Authors: Gayathri M , Pranesh S , Siddheshwar P G
Published: September 2023

Linear stability analysis is conducted to investigate the longitudinal and transverse rolls (TRs) generated in Rayleigh–Bénard convection in mono and hybrid nanoliquids confined between two infinite inclined parallel slots. Thermophysical properties of six mono nanoliquids and fifteen hybrid nanoliquids are calculated for different volume fractions (0.5%, 1%, 2%) using phenomenological laws and mixture theory. The shooting method is used to solve boundary eigenvalue problems to obtain the eigenvalues for 16 different boundary conditions. It is observed that as the inclination angle is increased, it delays the onset of longitudinal rolls in the case of all boundary conditions. However, it advances the onset of TRs except when the lower plate is adiabatic. The addition of mono and hybrid nanoparticles results in the advancement of the onset of convection. The addition of SWCNT and SWCNT—

Al
2

O
3

accelerates the onset of convection the most while Cu and Cu-Ag accelerates the onset of convection the least amongst the mono and hybrid nanoparticles considered in the study.
Determination of optimum parameters for measuring sea level using GNSS Interferometric Reflectometry: A Case study of Port Klang, Malaysia
Authors: Idris Ahmad Hilmi Mohamad , Sulaiman Saiful Aman , Tahar Khairul Nizam , Natnan Shahrul Reza , Satirapod Chalermchon
Published: September 2023

This paper presents a new approach of measuring sea level height using Global Navigation Satellite Systems GNSS Interferometric Reflectometry (GNSS-IR) by method of Signal to Noise Ratio (SNR) data analysis from a single geodetic receiver. The study location was selected at Port Klang Tide Gauge (PKTG) station, Malaysia. The purpose of this study was to identify the optimum criteria for the parameters involved to get the best accuracy of reflected heights. The accuracy of reflected height derived from SNR information is strongly dependent on the value of parameters used for quality control. The parameters involved shall achieve the best possible frequency correlated with the sea surface. There are 5 parameters were identified such as estimation of the satellite's azimuth and elevation angle, identify noise frequency range, selection of frequency amplitude power, and calculation of the peak frequency to noise ratio using the Lomb-Scargle periodogram (LSP). The optimum value of each parameter is important to get accurately selected reflector heights and then produce a quality local sea level time series.
Cycling Route Mapping via Cartography and GIS Techniques
Authors: Mustapha Nurul Iffah , Rasam Abdul Rauf Abdul , Saraf Noraain Mohamed , Idris Roslina , Wakijan Azizah
Published: September 2023

Cycling has been embraced as a mode of transportation with numerous health and environmental benefits, yet it is underfunded and needs more priority in many central cities in Malaysia. Despite a will from the Shah Alam City Council (MBSA) to enhance sustainable transport, cycling requires being accorded its due position in urban areas. It implies the presence of bottlenecks and barriers in the cycle route map. A cycling or bike map is designed specifically for cyclists addressed in the city using cartography and Geographical Information System (GIS) techniques. Four stages of operations were applied in the study, including a preliminary study, data collection, data processing and data visualization. The first result identified the significant criteria and features of the cycling route map since there are no specific features or concepts in designing the ideal cycling route map of the city. The criteria include the essential elements of cartography, the ideal design of cartography content and principle and relevant features in a standard cycling map. A proposed cycling route map was created with significant features such as route routes, route information, point of interest, land use and sign, and designated cycle route. The map testing revealed that the proposed map was practical since respondents had positive feedback. Having a suitable cycling map will benefit the cyclist to become one of the modes of transportation in the city.
The Exploratory Study of Normalized Indicator of Heat Vulnerability Index (HVI) By Using Functional Relationship
Authors: Latif Siti Zubaidah Abdul , Salleh Siti Aekbal , Salim Pauziyah Mohamad , Saraf Noraain Mohamed , Halim Maisarah Abdul , Idris Ahmad Norhisyam , Mustaha Emad , Pintor Lynlei
Published: September 2023

Extreme urban heat, a major environmental stressor caused by urbanisation, poses a substantial hazard to human health and well-being. The environmental, demographic, and health-related risk factors for heat stress must be identified as the urban population grows. As a result, this study provides insight into city people’ heat susceptibility and its extent at the district level. This examination was carried out using a multivariate index that included evaluations of the exposure, sensitivity, and coping ability components. Using nine indicators for three different characteristics, this study examined data on the spatial distribution from diverse sources such as satellite imaging processing and quantitative analysis output. This study employed a normalised indicator method that used functional relationships to normalise all of the indicators in the unit or a scale-free method. The index’s value of each parameter is then processed using weightage formula. Kuala Lumpur district has been rated as the most vulnerable to heat, followed by Petaling and Hulu Langat, according to the heat vulnerability index produced. The findings demonstrated a regional pattern of heat vulnerability, with significant differences between individual spatial indexes. While exposure and adaptive capacities have a distinct regional pattern, sensitivity has a more complicated spatial pattern. All factors were statistically significant as markers in the development of the heat vulnerability index, according to this study. In a highly dynamic metropolitan region, these criteria can be used for both urban planning and suggesting special strategies to reduce heat dangers.
Spatial Distribution and the Influence of Surface Temperature and Green Area on Sea Turtle Nesting Sites in Peninsular Malaysia
Authors: Fadli S N , Idris N H , Osman M J , Othman N , Ishak M H I
Published: September 2023

Malaysia is home to four of the seven sea turtles in the world, with Malaysian islands being one of the potential areas for sea turtle landing and nesting. However, sea turtles are classified as endangered species because they face extinction mainly due to land use changes, human marine activities, and environmental factors. As a result, they are now among the most important resources for ecotourism. Green turtles are the most prevalent species (endangered), while the hawksbill turtle is one of the world’s most seriously endangered marine turtle species today. Hence, considering the importance of improving turtle habitat in Malaysia, this study investigated the sea turtle’s nesting site preference in Peninsular Malaysia using spatial analysis. The objectives of this study are (1) to map sea turtle nesting sites in Peninsular Malaysia for five years (from 2017-2021) and (2) to identify the influence of surface temperature and landscape characteristics on sea turtle nesting habitats. This study used the binomial regression method to determine the significant environmental factors such as temperature, distance from the green area and the coastal line that could influence the preference for sea turtle habitat. The results show a positive relationship between temperature and that more sea turtles will nest and land in the area with the higher temperature. Also, more sea turtles prefer to land and nest near green areas. These findings confirmed the influence of green areas in turtle nesting sites in Peninsular Malaysia. It could assist the authorities in further understanding the importance of green areas in turtle nesting site preference and developing a mitigation plan to protect sea turtle habitat.
Landslide Susceptibility Mapping in Ampang Jaya: Comparing Probabilistic Method and Weighted Overlay Method
Authors: Samsul Siti Nur Aishah , Idris Roslina , Zulkarnain Siti Hafsah , Ahmad Che Bon , Rasam Abdul Rauf , Idris Mohd Rizal
Published: September 2023

When it came time to produce the map, the entire district of Ampang Jaya was chosen as the area for the research. These two approaches gave very different results in terms of accuracy. The results of the map were categorised using a range of different classification techniques, some of which include Natural Breaks and Equal Interval, respectively. Various landslide susceptibility hazard zoning results were found when the two different classification systems were applied to the data. These zoning areas need to go through an accuracy assessment process in order to be validated. The accuracy of the model was evaluated by comparing the findings about the historical locations of landslide occurrences with the findings regarding the susceptibility hazard locations of potential landslide areas. Because the accuracy of the Probabilistic technique was 66.67% for Equal Interval and 73.33% for Natural Breaks, respectively, this demonstrates that the Probabilistic method produces more dependable results than the Weighted Overlay method produces. Therefore, the accuracy assessment results indicate that the probabilistic method provides more reliable information for accuracy assessment than the Weighted Overlay method. This is due to the fact that the result of the accuracy assessment obtained from Weighted Overlay is significantly lower than that obtained from Probabilistic for each classification technique.