Article
Chemistry, Physical
Christian Wolf, Stephan Voelkers, Igor Kryukov, Markus Grass, Niklas Sommer, Stefan Boehm, Maxim Wunder, Nadine Koehler, Peter Maeckel
Summary: This paper studies the potential of directional ultrasonic wave superposition using moving sound generators for laser beam welding of high-strength steel alloys. The experiments show that a suitable superposition of ultrasonic waves by the moving sound generators can improve the distribution of AlSi particles in the melt as well as the microstructure within the weld, thus enhancing the performance of the welding.
Article
Optics
Oguz Tuncel, Hakan Aydin, Kemal Davut
Summary: This study examines the impact of heat input on the softening of the heat-affected zone (HAZ) in fiber laser welding of quenched 1.1 mm thick 22MnB5 steel. The study considers laser power (1500-2500 W) and welding speed (40-120 mm/s) as the input process variables. Results reveal that a minimum heat input of 50 J/mm is necessary for complete weld penetration. The research also finds that an increase in heat input leads to grain coarsening, which causes a 39% decrease in hardness in the HAZ region compared to the base material.
OPTICS AND LASER TECHNOLOGY
(2023)
Article
Optics
Rongrong Huang, Caiwang Tan, Yiming Sun, Xiangtao Gong, Laijun Wu, Bo Chen, Hongyun Zhao, Xiaoguo Song
Summary: The study showed that different processing windows could be obtained by changing the defocused distances to achieve varied appearances and microstructure. Increasing the laser spot diameter expanded the processing window but also led to an increase in the thickness of the interfacial intermetallic layer. During tensile-shear testing of the laser welded-brazed joints, two fracture modes were observed.
OPTICS AND LASER TECHNOLOGY
(2021)
Article
Optics
Wei Xu, Wu Tao, Haiwen Luo, Shanglu Yang
Summary: The effect of Al-Si coating on the weld bead formation, aluminum element distribution, microstructure, and mechanical properties of laser welded 22MnB5 steel joint was studied. It was found that increasing welding speed helped to reduce the concavity depth of the weld surface. The uneven distribution of aluminum element in the fusion zone during welding process resulted in softened weld and reduced hardness.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Optics
Weizhe Du, Jiejie Xu, Rongshi Xiao, Ting Huang
Summary: Laser micro-welding is different from macro-welding due to smaller weld dimensions. Research on the influence of welding modes on microstructure and corrosion resistance is lacking. This study uses a single-mode fiber laser to weld stainless steel foils, and identifies two welding modes: thermal conduction welding and penetration welding. The transient phase of laser-material interaction is caused by oxidation during penetration welding, while gas protection eliminates this phase. The conduction weld exhibits better corrosion resistance due to different heat transfer behavior compared to the penetration weld.
OPTICS AND LASER TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Wei Xu, Zhigong Jiang, Jiazhi Zhang, Wu Tao, Xuzhi Zhang, Shanglu Yang
Summary: A patented laser-filler wire welding process was developed to inhibit the formation of a-ferrite and achieve high quality laser weld in Al-Si coated 22MnB5 steels without removing the coating. The use of a designated filler wire reduced Al segregation and resulted in a microstructure of full martensite with high dislocation density. The tensile strength and elongation of the welded joint increased significantly compared to welding without a filler wire.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Optics
Jin Yang, Ming Xiao, Lingqing Wu, Zhuguo Li, Hongbing Liu, Yixuan Zhao, Wei Guo, Caiwang Tan
Summary: This study investigated the laser welding-brazing of 5052 aluminum alloys and Al-Si coated 22MnB5 steel using a Zn-22Al filler metal. The results showed that the weld appearance, interfacial microstructure, and mechanical properties were significantly affected by the laser power. The interfacial microstructure and mechanical properties changed with the increase of laser power, with the maximum tensile strength obtained at 1900 W laser power. Numerical simulations revealed the increase in interfacial temperature with the increase of laser power, resulting in the change of joint mechanical properties.
OPTICS AND LASER TECHNOLOGY
(2023)
Article
Optics
M. H. Razmpoosh, M. Shehryar Khan, A. Ghatei Kalashami, A. Macwan, E. Biro, Y. Zhou
Summary: The study demonstrates that laser beam defocusing can successfully alleviate excessive weld concavity during laser welding of Zn-coated 22MnB5 steel, thereby improving the dynamic loading performance of the welds.
OPTICS AND LASER TECHNOLOGY
(2021)
Article
Automation & Control Systems
Mariane Chludzinski, Rafael Eugenio dos Santos, Cristina Churiaque, Marta Ortega-Iguna, Jose Maria Sanchez-Amaya
Summary: Aluminium alloys have eco-friendly characteristics, such as almost unlimited recyclability, that are related to global environmental issues. However, the high thermal conductivity and low melt point of these alloys pose challenges in exploring their full benefits. This study used pulsed laser welding to analyze the effect of welding parameters on AA5083 aluminium alloy sheets. Statistical methods were employed to develop sound welds with minimal defects and high penetration depth. Variation in peak power, spot diameter, and pulse duration resulted in an optimal parameter arrangement, and the use of different pulse shapes helped mitigate crack formation and pores, ultimately achieving crack-free spot welds.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2022)
Article
Materials Science, Multidisciplinary
Xiaoou Zhu, Zhanqi Liu, Guili Yin, Haijiang Wang, Jingtao Ren
Summary: The influence of magnetic field on the microstructure and properties of laser wire-filled welded joints of 1.5 mm automotive 22MnB5 steel was investigated. The results showed that a 5 mT and 15 mT steady magnetic field promoted the flow of molten pool, reduced the width of the welded joint, decreased the grain size of the coarse grain region, and improved the overall hardness of the welded joint. However, different magnetic induction intensities had different effects on the solid phase transformation of the weld, with 15 mT inducing the formation of lath martensite and lower bainite, resulting in higher mechanical properties.
MATERIALS RESEARCH EXPRESS
(2023)
Article
Materials Science, Multidisciplinary
Danfeng Zhang, Youqiong Qin, Feng Zhao, Min Liang
Summary: Laser welding of Al-Si coated 22MnB5 hot stamping steel/galvanized steel with different laser power, welding speed, and coating conditions was studied in this research. The changes in weld appearance, microstructure, and mechanical properties of the joints were analyzed. Higher laser power or lower welding speeds resulted in wider bead width and more intense weld pool flow, affecting the diffusion of Al and mechanical properties of the joints.
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
(2022)
Article
Chemistry, Physical
Hongwei Sun, Jialei Zhu, Benshun Zhang, Chao Liu, Chunyu Miao, Kai Wang, Xiaoxin Zhao
Summary: This paper developed the optimization of laser-MAG hybrid welding parameters for 10CrNi3MoV ship steel. The regression model associated with welding parameters was established based on response indices such as penetration and tensile strength. The optimized parameters were determined to be laser power of 3700 W, welding speed of 0.8 m/min, and wire feeding speed of 7 m/min. The maximum penetration achieved was 8 mm, meeting the mechanical performance inspection standards.
Article
Engineering, Multidisciplinary
Xiaobing Cao, Zhou Li, Xiongfeng Zhou, Zhi Luo, Ji'an Duan
Summary: The quantitative analysis of resistance spot welded 5052 aluminum to Al-Si coated boron steel was conducted using response surface methodology and genetic algorithm, optimizing parameters and verifying significance and accuracy. The optimized sample exhibited a sound appearance and improved shear strength, indicating the significant role of Al Si coating in RSW of aluminum to steel.
Article
Materials Science, Multidisciplinary
Feng Zhao, Youqiong Qin, Danfeng Zhang, Min Liang
Summary: By using laser lap welding with filler wire, the accumulation of delta-ferrite can be suppressed and the dilution of the Al-Si coating can be adjusted, resulting in improved weld appearance and mechanical properties.
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
(2022)
Article
Materials Science, Multidisciplinary
Ping Yao, Hongyan Lin, Wei Wu, Heqing Tang
Summary: In wire and arc additive manufacturing (WAAM), the double-pulse mode shows better performance by stirring the molten pool, achieving finer microstructure, and better properties; increasing the duty ratio leads to higher heat input, resulting in decreased height, increased width, reduced hardness and tensile strength of the specimens.
Article
Polymer Science
Yasir Raza, Hassan Raza, Arslan Ahmad, Moinuddin Mohammed Quazi, Muhammad Abid, Monis Raza Kazmi, S. M. Ashrafur Rahman, Z. M. Zulfattah, I. M. Rizwanul Fattah
Summary: The study focused on analyzing and optimizing the tensile properties of graphene-polystyrene nanocomposites, demonstrating that the incorporation of graphene in the polystyrene matrix significantly improves its mechanical properties. The concentration of graphene was identified as a critical parameter, with the optimized combination being 0.60 wt.% graphene, 10 minutes of sonication time post-mixing, and a sonication temperature of 25 degrees Celsius. The results showed a maximum increase of 97.36% in ultimate tensile strength, 82.70% in elongation, and 174.08% in elastic modulus compared to pristine polystyrene.
JOURNAL OF POLYMER RESEARCH
(2021)
Review
Energy & Fuels
M. Naveed, A. Arslan, H. M. A. Javed, T. Manzoor, M. M. Quazi, T. Imran, Z. M. Zulfattah, M. Khurram, I. M. R. Fattah
Summary: This study provides a detailed review and critical analysis of the use of vegetable oils as cutting fluids, highlighting their comparable performance to mineral oil-based products and proposing solutions to potential issues. It emphasizes the benefits of vegetable oil-based cutting fluids and discusses the selection of non-edible vegetable oils to avoid shortages of edible oils.
Article
Engineering, Mechanical
A. Q. Zaifuddin, F. Zulhilmi, M. H. Aiman, M. M. Quazi, M. Ishak
Summary: The study focused on increasing the surface roughness of titanium alloy through laser surface modification (LSM), which resulted in improved energy absorption capabilities. It was found that increasing laser power during LSM process significantly enhanced surface roughness and increased laser heating temperature.
JOURNAL OF MECHANICAL ENGINEERING AND SCIENCES
(2021)
Article
Engineering, Electrical & Electronic
M. Nasir Bashir, Hafiz Muhammad Saad, Muhammad Rizwan, M. M. Quazi, Muhammad Mahmood Ali, Arslan Ahmed, Asad A. Zaidi, Manzoore Elahi M. Soudagar, A. S. M. A. Haseeb, Sumsun Naher
Summary: Due to the toxic properties of lead, the use of lead-free solder materials has become a necessary trend in the electronic packaging industry. This study focuses on the suppression of brittleness in Sn-58Bi alloy by adding different percentages of Sn powder. The results show that the dissolution of Sn particles significantly improves the mechanical strength and strain value of the Sn-58Bi alloy.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2022)
Article
Engineering, Electrical & Electronic
M. Nasir Bashir, A. S. M. A. Haseeb, Saif Wakeel, Muhammad Ali Khan, M. M. Quazi, Niaz Bahadur Khan, Arslan Ahmed, Manzoore Elahi M. Soudagar
Summary: This study investigates the effect of Ni and Co nanoparticle-doped flux on the microstructure of the solder joint. The results show that the addition of Ni and Co nanoparticle-doped flux can reduce the size of IMC particles and beta-Sn grains in the eutectic region, leading to improved mechanical and structural properties of the joint.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2022)
Article
Engineering, Mechanical
Varun Goel, Naresh Kumar, Paramvir Singh, M. A. Fazal, M. M. Quazi
Summary: The present study investigates the effect of fuel on engine wear by comparing the friction and wear characteristics of Jasmine biodiesel and its blends with diesel. The results show that biodiesel exhibits better lubricity and reduces wear compared to diesel.
JOURNAL OF THE BRAZILIAN SOCIETY OF MECHANICAL SCIENCES AND ENGINEERING
(2022)
Article
Engineering, Electrical & Electronic
M. Nasir Bashir, Niaz Bahadur Khan, Shahid Bashir, Abdul Faheem Khan, M. M. Quazi, Mustabshirha Gul, Saif Wakeel, Hafiz Muhammad Saad
Summary: Migration of Cu atoms from the cathode side to the anode side causes void formation in the solder joint, which is the root cause of electromigration failures in lead-free solder joints. This study investigates the effects of Zn nanoparticle-doped flux on the mechanical properties of SAC305 solder joint under high current density. The results show that the addition of Zn nanoparticle-doped flux improves the mechanical strength of the solder joint and suppresses Cu migration, preventing fracture path shift.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2023)
Article
Metallurgy & Metallurgical Engineering
M. F. M. Yusof, M. M. Quazi, S. A. A. Aleem, M. Ishak, M. F. Ghazali
Summary: This study improves weld defect identification by incorporating Z-score-based thresholding into the wavelet denoising algorithm for the pre-processing of sound signals. The introduction of the Z-score threshold significantly reduces the dispersion trend of sound features, leading to a more accurate classification of weld defects.
WELDING IN THE WORLD
(2023)
Article
Materials Science, Multidisciplinary
Abdul Ahad Hussain, Kashif Kamran, Maryam Hina, Mubashera Ishaq, Muhammad Y. Naz, Shahid Bashir, Nadeem Sarwar, Moinuddin Mohammed Quazi
Summary: Electrokinetics is effective in removing contaminants, but its field-scale applications are limited by the high energy cost. This study investigates the energy consumption of electrokinetics by varying the initial salt concentration and treatment time of soil specimens contaminated with different concentrations of sodium chloride. The results show that the removal of Na+ is higher than Cl- for specimens with lower salt concentration, but the opposite is true for specimens with higher salt concentration. The electroosmotic flow and salt ions removal rates decrease with increasing treatment time due to the development of acidic and alkaline environments in soil.
MATERIALS RESEARCH EXPRESS
(2023)
Article
Green & Sustainable Science & Technology
A. Shehzad, A. Arslan, F. Rehman, M. M. Quazi, S. I. Butt, M. Jamshaid
Summary: This study investigates the corrosion behavior of automotive materials in bio-based fuels. The Response Surface Methodology (RSM) is used to evaluate the corrosion rates of copper, aluminium, and stainless steel when exposed to chicken fat-based biodiesel. It was found that copper, aluminium, and stainless steel showed minimum corrosion rate at a blend percentage of 5.86% and maximum corrosion rate at blend percentage of 34.14% when immersed for 920 hours. The surface morphology of the materials was investigated, revealing that copper was the most corrosive material followed by aluminium and stainless steel 316 l in chicken fat oil-based biodiesel.
SUSTAINABLE ENERGY TECHNOLOGIES AND ASSESSMENTS
(2023)
Article
Engineering, Mechanical
M. H. Zul, M. Ishak, R. M. Nasir, M. H. Aiman, M. M. Quazi
Summary: The aim of this study was to investigate the effect of laser-textured surfaces on enhancing the wear performance of Ti6Al4V. Laser texturing was applied to the sample with preset parameter values. The results showed that the laser-textured surface of Ti6Al4V exhibited a significant improvement in wear rate compared to the original surface.
INTERNATIONAL JOURNAL OF AUTOMOTIVE AND MECHANICAL ENGINEERING
(2023)
Editorial Material
Biochemistry & Molecular Biology
Mohammadamin Ezazi, M. M. Quazi, Hossein Taheri
Review
Biochemistry & Molecular Biology
Mohammadamin Ezazi, M. M. Quazi
Summary: The industrialization in the last century has led to a significant increase in water pollution, particularly from oil contaminants and discharges from various industries. Treating the large volumes of oily wastewater effectively has become a major challenge. This article provides a brief review of recent advancements in oil-water separation membranes modified with two-dimensional materials, highlighting MXenes, graphenes, metal-organic frameworks, and covalent organic frameworks. The review covers their backgrounds, concepts, fabrication methods, and the latest representative studies, and concludes by discussing the challenges and future research directions.
Article
Materials Science, Multidisciplinary
M. Y. Yuserny, M. H. Aiman, M. M. Quazi, M. Ishak, J. Shamini
Summary: Brazing is a 5000 year old joining process that still faces advanced challenges today. Laser brazing offers unique advantages, such as the ability to joint dissimilar materials, and indirect laser brazing can minimize the formation of a brittle intermetallic compound layer. This study investigates the viability of indirect laser brazing between Ti6Al4V and 316L stainless steel.
LASERS IN ENGINEERING
(2021)
Article
Materials Science, Multidisciplinary
A. Q. Zaifuddin, M. H. Aiman, M. M. Quazi, M. Ishak, J. Shamini
Summary: This study investigated the effect of laser surface texturing parameters on the surface morphology and roughness of Ti6Al4V, finding that an increase in laser power along with a decrease in frequency and scan speed can lead to increased surface roughness. Additionally, the impact of surface roughness on laser heating temperature was also studied, revealing that a rougher surface can result in a significantly higher maximum temperature compared to a polished surface due to energy scattering and absorption amplification.
LASERS IN ENGINEERING
(2021)
Article
Engineering, Multidisciplinary
Sicheng Jiao, Shixiang Wang, Minge Gao, Min Xu
Summary: This paper presents a non-contact method of thickness measurement for thin-walled rotary shell parts based on a chromatic confocal sensor. The method involves using a flip method to obtain surface profiles from both sides of the workpiece, measuring the decentration and tilt errors of the workpiece using a centering system, establishing a unified reference coordinate system, reconstructing the external and internal surface profiles, and calculating the thickness. Experimental results show that the method can accurately measure the thickness of a sapphire spherical shell workpiece and is consistent with measurements of other materials.
Article
Engineering, Multidisciplinary
Rajeev Kumar, Sajal Agarwal, Sarika Pal, Alka Verma, Yogendra Kumar Prajapati
Summary: This study evaluated the performance of a CaF2-Ag-MXene-based surface plasmon resonance (SPR) sensor at different wavelengths. The results showed that the sensor achieved the maximum sensitivity at a wavelength of 532 nm, and higher sensitivities were obtained at shorter wavelengths at the expense of detection accuracy.
Article
Engineering, Multidisciplinary
Attilio Di Nisio, Gregorio Andria, Francesco Adamo, Daniel Lotano, Filippo Attivissimo
Summary: Capacitive sensing is a widely used technique for a variety of applications, including avionics. However, current industry standard Capacitive Level Sensors (CLSs) used in helicopters perform poorly in terms of sensitivity and dynamic characteristics. In this study, novel geometries were explored and three prototypes were built and tested. Experimental validation showed that the new design featuring a helicoidal slit along the external electrode of the cylindrical probe improved sensitivity, response time, and linearity.
Article
Engineering, Multidisciplinary
Kai Yang, Huiqin Wang, Ke Wang, Fengchen Chen
Summary: This paper proposes an effective measurement method for dynamic compaction construction based on time series model, which enables real-time monitoring and measurement of anomalies and important construction parameters through simulating motion state transformation and running time estimation.
Article
Engineering, Multidisciplinary
Hui Fu, Qinghua Song, Jixiang Gong, Liping Jiang, Zhanqiang Liu, Qiang Luan, Hongsheng Wang
Summary: An automatic detection and pixel-level quantification model based on joint Mask R-CNN and TransUNet is developed to accurately evaluate microcrack damage on the grinding surfaces of engineering ceramics. The model is effectively trained on actual micrograph image dataset using a joint training strategy. The proposed model achieves reliable automatic detection and fine segmentation of microcracks, and a skeleton-based quantification model is also proposed to provide comprehensive and precise measurements of microcrack size.
Review
Engineering, Multidisciplinary
Sang Yeob Kim, Da Yun Kwon, Arum Jang, Young K. Ju, Jong-Sub Lee, Seungkwan Hong
Summary: This paper reviews the categorization and applications of UAV sensors in forensic engineering, with a focus on geotechnical, structural, and water infrastructure fields. It discusses the advantages and disadvantages of sensors with different wavelengths and addresses the challenges of current UAV technology and recommendations for further research in forensic engineering.
Article
Engineering, Multidisciplinary
Anton Nunez-Seoane, Joaquin Martinez-Sanchez, Erik Rua, Pedro Arias
Summary: This article compares the use of Mobile Laser Scanners (MLS) and Aerial Laser Scanners (ALS) for digitizing the road environment and detecting road slopes. The study found that ALS data and its corresponding algorithm achieved better detection and delimitation results compared to MLS. Measuring the road from a terrestrial perspective negatively impacted the detection process, while an aerial perspective allowed for scanning of the entire slope structure.
Article
Engineering, Multidisciplinary
Nur Luqman Saleh, Aduwati Sali, Raja Syamsul Azmir Raja Abdullah, Sharifah M. Syed Ahmad, Jiun Terng Liew, Fazirulhisyam Hashim, Fairuz Abdullah, Nur Emileen Abdul Rashid
Summary: This study introduces an enhanced signal processing scheme for detecting mouth-click signals used by blind individuals. By utilizing additional band-pass filtering and other steps, the detection accuracy is improved. Experimental results using artificial signal data showed a 100% success rate in detecting obstacles. The emerging concepts in this research are expected to benefit radar and sonar system applications.
Article
Engineering, Multidisciplinary
Jiqiang Tang, Shengjie Qiu, Lu Zhang, Jinji Sun, Xinxiu Zhou
Summary: This paper studies the magnetic noise level of a compact high-performance magnetically shielded room (MSR) under different operational conditions and establishes a quantitative model for magnetic noise calculation. Verification experiments show the effectiveness of the proposed method.
Review
Engineering, Multidisciplinary
Krzysztof Bartnik, Marcin Koba, Mateusz Smietana
Summary: The demand for miniaturized sensors in the biomedical industry is increasing, and optical fiber sensors (OFSs) are gaining popularity due to their small size, flexibility, and biocompatibility. This study reviews various OFS designs tested in vivo and identifies future perspectives and challenges for OFS technology development from a user perspective.
Article
Engineering, Multidisciplinary
Yue Wang, Lei Zhou, Zihao Li, Jun Wang, Xuangou Wu, Xiangjun Wang, Lei Hu
Summary: This paper presents a 3-D reconstruction method for dynamic stereo vision of metal surface based on line structured light, overcoming the limitation of the measurement range of static stereo vision. The proposed method uses joint calibration and global optimization to accurately reconstruct the 3-D coordinates of the line structured light fringe, improving the reconstruction accuracy.
Article
Engineering, Multidisciplinary
Jaafar Alsalaet
Summary: Order tracking analysis is an effective tool for machinery fault diagnosis and operational modal analysis. This study presents a new formulation for the data equation of the second-generation Vold-Kalman filter, using separated cosine and sine kernels to minimize error and provide smoother envelopes. The proposed method achieves high accuracy even with small weighting factors.
Article
Engineering, Multidisciplinary
Tonglei Cao, Kechen Song, Likun Xu, Hu Feng, Yunhui Yan, Jingbo Guo
Summary: This study constructs a high-resolution dataset for surface defects in ceramic tiles and addresses the scale and quantity differences in defect distribution. An improved approach is proposed by introducing a content-aware feature recombination method and a dynamic attention mechanism. Experimental results demonstrate the superior accuracy and efficiency of the proposed method.
Article
Engineering, Multidisciplinary
Qinghong Fu, Yunxi Lou, Jianghui Deng, Xin Qiu, Xianhua Chen
Summary: Measurement and quantitative characterization of aging-induced gradient properties is crucial for accurate analysis and design of asphalt pavement. This research proposes the composite specimen method to obtain asphalt binders at different depths within the mixture and uses dynamic shear rheometer tests to measure aging-induced gradient properties and reveal internal mechanisms. G* master curves are constructed to investigate gradient aging effects in a wide range. The study finds that the composite specimen method can effectively restore the boundary conditions and that it is feasible to study gradient aging characteristics within the asphalt mixture. The study also observes variations in G* and delta values and the depth range of gradient aging effects for different aging levels.
Article
Engineering, Multidisciplinary
Min Li, Kai Wei, Tianhe Xu, Yali Shi, Dixing Wang
Summary: Due to the limitations of ground monitoring stations in China for the BDS, the accuracy of BDS Medium Earth Orbit (MEO) satellite orbits can be influenced. To overcome this, low Earth orbit (LEO) satellites can be used as additional monitoring stations. In this study, data from two LEO satellites were collected to improve the precise orbit determination of the BDS. By comparing the results with GPS and BDS-2/3 solutions, it was found that including the LEO satellites significantly improved the accuracy of GPS and BDS-2/3 orbits.
