bluuebunny/crossref_metadata_2025_split huggingface dataset:
Airworthiness Requirements for Drainage Ground Test of Flammable Liquids from Transport Aircraft
Authors: Dong Jiaxuan 
Published: August 2023

Abstract
The leakage and ignition of flammable liquids such as fuel and hydraulic liquid on transport aircraft are extremely harmful to aircraft and passengers. The drainage design is an effective means to reduce the probability of ignition and the resultant hazards if ignition does occur. The drainage test is required to show compliance with Article 25.863, and the drainage ground test must be performed before the flight test. This paper deeply studies Draft AC 25.863 and gives the airworthiness requirements for the drainage ground test of flammable liquids in combination with model practice. It provides a reference for the ground drainage compliance verification in the flammable liquid leakage area of transport aircraft.
Research on High Voltage Protection of Arc Thruster Power Control Unit
Authors: Peng Zheng , Li Zongliang , Li Ze , Song Fei , Li Zhong , Liu Yizhuo 
Published: August 2023

Abstract
The arc propulsion system needs a high-voltage (3800 V) pulse to break down the working medium in the thruster and form a stable arc. The arc thruster power control unit (ATPU) is prone to producing high voltage discharge when the high voltage pulse is output. According to the high voltage breakdown mechanism, this paper puts forward control measures to prevent the high voltage breakdown.
LEO Satellite Localization of Receiver in Motion Using Signal Frequency of Arrival
Authors: Guo Fangfang , Shen Yuyao 
Published: August 2023

Abstract
This study presents a localization algorithm for moving the receiver based on LEO satellite downlink Doppler signals. This algorithm could provide an alternative to pseudo-range based GNSS. Considering the asynchrony between satellites and the existence of a relative clock skew, we used sequential measurements at multiple receiving moments to obtain a sufficient number of observations. And we performed motion offset compensation for the receiver position and velocity at different moments. Simulation results show that the algorithm can achieve good localization accuracy.
A Digital Twin Based Residual Stress Prediction Method for Turbine Blades
Authors: Mou Sheng , Bu Kun , Liu Jun , Ren Shengjie , Zhang Ruiyuan , Bai Boxian 
Published: August 2023

Abstract
The investment casting process is the conventional method for manufacturing turbine blades, and the residual stress generated through this process is widely regarded as a critical factor that markedly impacts the quality and serviceability of turbine blades. However, real-time measurement of residual stress is extremely complex and expensive, especially for single-crystal turbine blades. Current experimental measurement techniques such as X-ray or neutron diffraction can only measure residual stresses at specific points or within a very small area. Studies on residual stress of turbine blades are mainly performed by finite element (FE) simulation, but the accuracy is difficult to guarantee due to the inability to establish accurate mathematical models for complex physical systems. To address this issue, this paper proposes utilizing a digital twin (DT) model to predict residual stresses in turbine blades. By combining real-time sensor and FE simulation data, the DT model is able to update and correct the mathematical models, resulting in more accurate predictions compared to traditional FE simulations.
A Fast Image Matching Method Based on Improved SURF
Authors: Jiang Haili , Liu Panpan , Yang Qingqing , Xu Liang , Zhang Shuai 
Published: August 2023

Abstract
In order to solve the problems of low matching accuracy, slow speed and high system overhead in image matching methods, a rotation binary descriptor construction method based on Speed Up Robust Features (SURF) feature point detection is designed by using different Fast Library for Approximate Nearest Neighbors (FLANN) parameters and the filtering mechanism to screen out wrong matches according to the types of feature descriptors constructed in different feature extraction algorithms. This method ensures scale and rotation invariant while simplifying the representation of feature descriptors and speeding up the calculation speed in the initial stage of matching by combining the binary characteristics of descriptors. Finally, the Hamming distance is used as the filtering mechanism to improve the success rate of the final matching. The experimental results show that the accuracy of image matching is improved by 1.5% and the matching time is improved by 0.116s, while the robustness of the image to noise and rotation is ensured.
Early warning signals of changing resilience in the biogeochemistry and biology of a northern hardwood forest
Authors: Contosta Alexandra R , Battles John J , Campbell John L , Driscoll Charles T , Garlick Sarah R , Holmes Richard T , Likens Gene E , Rodenhouse Nicholas L , Rogers Shannon H , Templer Pamela H , Vadeboncoeur Matthew A , Groffman Peter M 
Published: August 2023

Abstract
Resilience is the ability of ecosystems to maintain function while experiencing perturbation. Globally, forests are experiencing disturbances of unprecedented quantity, type, and magnitude that may diminish resilience. Early warning signals are statistical properties of data whose increase over time may provide insights into decreasing resilience, but there have been few applications to forests. We quantified four early warning signals (standard deviation, lag-1 autocorrelation, skewness, and kurtosis) across detrended time series of multiple ecosystem state variables at the Hubbard Brook Experimental Forest, New Hampshire, USA and analyzed how these signals have changed over time. Variables were collected over periods from 25 to 55 years from both experimentally manipulated and reference areas and were aggregated to annual timesteps for analysis. Long-term (>50 year) increases in early warning signals of stream calcium, a key biogeochemical variable at the site, illustrated declining resilience after decades of acid deposition, but only in watersheds that had previously been harvested. Trends in early warning signals of stream nitrate, a critical nutrient and water pollutant, likewise exhibited symptoms of declining resilience but in all watersheds. Temporal trends in early warning signals of some of groups of trees, insects, and birds also indicated changing resilience, but this pattern differed among, and even within, groups. Overall, ∼60% of early warning signals analyzed indicated decreasing resilience. Most of these signals occurred in skewness and kurtosis, suggesting ‘flickering’ behavior that aligns with emerging evidence of the forest transitioning into an oligotrophic condition. The other ∼40% of early warning signals indicated increasing or unchanging resilience. Interpretation of early warning signals in the context of system specific knowledge is therefore essential. They can be useful indicators for some key ecosystem variables; however, uncertainties in other variables highlight the need for further development of these tools in well-studied, long-term research sites.
A study on stabilizing mechanism of flap countermeasures mitigating VIV of a box girder bridge section
Authors: Tam Phan Duc , Katsuchi Hiroshi , Jiaqi Wang , Tamura Hiroshi , Hirao Kensho 
Published: August 2023

Abstract
As bridge spans stretch, the structure becomes more flexible and susceptible to dynamic wind effects causing harmful wind-induced vibration. The biggest issue with the design of long-span bridges is the possibility of vibration caused by vortices. This study examines the mechanism of the decrease in the amplitude of vortex-induced vibration for the box girder using a flap countermeasure. Aerodynamic countermeasures such as a flap have successfully increased bridge deck aerodynamic stability. However, their stabilizing mechanism has yet to be fully understood. Based on the proposed approach, a wind tunnel experiment and a CFD technique are used to investigate the aerodynamic instability of the bridge girder in the presence of aerodynamic countermeasures. The flow fields surrounding the bridge deck, both with and without the flap, are examined, and the experiment outcomes are compared. Flow imagery is utilized to explain and understand the modified flow properties surrounding the bridge girder in the presence of aerodynamic countermeasures that minimize vibration amplitude. Indeed, installing flaps on a girder leads to increased turbulence over the surface and at the leeward side, which disrupts vortex formation and decreases lift forces on the structure. In addition, the results revealed that the efficiency of the flap is related to the installed location of the flap and the flap length. This research provides a reliable framework for designing the flap countermeasure and significantly improves the aerodynamic stability of a deck-flap system.
Buckling analysis of functionally graded plates in thermal environment by using a meshfree method
Authors: Ngo Binh Khanh , Le Tel Doc Tu , Lo Vay Siu , Nguyen Vy Khac , Truong Thien Tich 
Published: August 2023

Abstract
In material, the pre-stress state caused by temperature variation of the working environment is one of the main reasons which cause buckling in structures. This paper aims to analyse the critical temperature rise to cause buckling in functionally graded material (FGM) under different boundary conditions. Reissner-Mindlin plate theory is employed in this paper with the radial point interpolation method (RPIM). The RPIM has the advantage compared to other meshfree methods in the satisfaction of the Kronecker delta property which allows directly imposing boundary conditions on scattered nodes. Factors affecting to thermal buckling phenomenon are investigated. The accuracy of solutions will be shown by comparing them to reliable results in previous studies
Investigation of the shear behavior of ultra-high performance concrete girder by simulation approach
Authors: Dao Cong-Binh , Mai Viet-Chinh , Vu Ngoc-Quang , Pham Hoang 
Published: August 2023

Abstract
The present study investigates the shear behavior of the Ultra High Performance Concrete girder strengthened by steel bars and stirrups by simulation approach. Utilizing the Concrete Damage Plasticity model that involves strength reduction and nonlinear behavior of the material, 3D simulation models are established and analyzed by the commercial software Abaqus. The numerical simulation model is verified by comparing the test data to ensure reliability. Numerical simulation models were then developed to investigate the relationship of shear force with parametric studies of shear span to depth ratio, steel bar ratio and stirrups spacing. Based on the obtained results, the simulation model and test results show a good agreement. The relation between the shear capacity of UHPC girder and parametric studies was also enlightened.
Application of steel frame viaduct for mountainous roads in Vietnam: Case studies in Quang Ngai Province and Lam Dong Province
Authors: Tung Dang Dang , Tuan Nguyen Canh 
Published: August 2023

Abstract
Vietnam’s mountainous highways are increasingly affected by landslides each year, with climate change being a major cause. The government has allocated significant funds to repair, rehabilitate, and maintain these highways, but conventional methods like excavation and embankment are not always effective for roads that pass through unstable, large-angle slopes that have a high risk of landslides. This results in additional rehabilitation costs following natural disasters. To address this issue, JFE Civil Engineering & Construction Corporation has developed a new solution for constructing mountainous highways in Vietnam - a viaduct that functions as a space steel frame supported by steel pipe columns and beams. Prefabricated in a factory and transported to the construction site, the steel beams are then assembled, and steel piles are driven deep into the ground for a rigid pile-to-ground connection. These proposed structures offer sustainable and cost-effective solutions for mountainous highways with minimal impact on the surrounding environment. Two case studies in Quang Ngai Province and Lam Dong Province are presented as preliminary designs to demonstrate the feasibility of this solution.
Rotating uniform eddy current probe using four rectangular excitation coils with ferrite cores for cracks detection in conductive materials
Authors: Trung Le Quang , Miyazaki Seishu , Kasai Naoya , Sekino Kouichi 
Published: August 2023

Abstract
In this study, we introduce a new rotating uniform eddy current (RUEC) probe designed to identify artificial cracks in conductive materials. The RUEC probe comprises four rectangular coils, divided into two sets of diagonally positioned coils. By providing two alternating current sources with a 90° phase difference to the two sets of coils, a RUEC distribution with uniform amplitude in all directions can be produced on the surface of the test specimen. Furthermore, ferrite cores are integrated into the four coils to enhance the crack detection ability. To confirm that the RUEC probe model produces RUECs with uniform amplitude in all directions on the test specimen surface, we conducted finite element method (FEM) simulations. We then conducted experiments with the RUEC probe to identify artificial cracks of varying sizes on the test specimen. The experimental results demonstrate that the RUEC distribution on the test specimen surface enabled successful detection of cracks in all directions with the probe.
A case study of processing abnormal GNSS monitoring data of a cable-stayed bridge in Vietnam
Authors: Le Van Hien , Vo Duy Hung 
Published: August 2023

Abstract
Global Navigation Satellite System (GNSS) plays an important role in the real-time monitoring of superstructures, especially for long-span cable-stayed bridges. Currently, GNSS has been applied to integrate a Structural Health Monitoring system (SHMs) of many long-span cable-stayed bridges worldwide through its advantages in observing a large displacement of structures and monitoring the global deformation of bridges. However, some studies of actual GNSS monitoring data of a cable-stayed bridge showed that there are a lot of abnormal data occurrences such as missing data or several abnormal data. This paper investigates the application of some methods for processing the GNSS abnormal data acquired from an actual cable-stayed bridge in Vietnam. Firstly, a long-term monitoring dataset of an actual bridge was acquired for the study experiment. A clean-short dataset was used to investigate the accuracy and applicability of some methods in the interpolation of abnormal data, for example, linear formula, Moving Average, Artificial Neural Network, and Hampel Identifier. Some criteria are used to assess the difference between the interpolated data and actual data such as Root Mean Square Error (RMSE) or correlated coefficients with temperature data. Otherwise, the applied methods were then assessed their abilities and effectiveness in real applications, for instance, creating an automatic interpolated program of abnormal data.
Study on detecting deterioration in beam structure stiffness using deformed shape
Authors: Ngo Han-Cuong , Ha Tuan Minh , Fukada Saiji , Ho Duc-Duy 
Published: August 2023

Abstract
This study presents a diagnostic technique for identifying the loss of stiffness of homogeneous beams using only the deformed shape in an effort to develop more effective building health monitoring instruments. Method based on a correlation between beam deformation at two damaged and undamaged selection states. Diagnostic indicators such as the correlation coefficient (CC) and the absolute value of the mean deviation ratio (MAPD) are extensively used to determine the presence of decreased stiffness. Using an approach based on finite element analysis, the deformation line data is computed. Various failure scenarios are proposed to evaluate the beam damage detection sensitivity of the indicators. In the case of beam damage, the CC index value is less than 1, and in the absence of damage, it is equal to 1. Similarly, for the MAPD index, the value is greater than 0 in the case of damage to the beam and 0 in the case of no assumed failure. The result demonstrates that the deformed line data can be used to calculate the assessment indicators for determining the onset of damage in homogeneous beams. Indicators that have not yet determined the location of the local stiffness decline on the beam when using input data are the deformed shape corresponding to the survey examples in this study.
Roadway departure crashes in Vietnam: identifying the sequence of events, causes, and countermeasures by applying the crash reconstruction technique
Authors: Nguyen Dinh Vinh Man , Vu Anh Tuan 
Published: August 2023

Abstract
The horizontal curve segment is where traffic crashes often occur in rural areas of Vietnam. Although many safety countermeasures have been implemented, their effectiveness still needs to improve. The main reason is that the implemented countermeasures are unfit for the crash causes. More specifically, determining crash causes and contributory factors to the severity of crashes needs to be more accurate because of the need for more critical data and specialized analytical tools. This study applies the crash reconstruction technique to simulate, reconstruct, and analyze crashes that occurred at horizontal curve segments to address the abovementioned issues. The study results have reproduced the sequence of events, crash causes, and contributory factors to the severity of roadway departure crashes of four-wheeled vehicles in rural areas. This research is a scientific foundation to help researchers choose the suitable technique to reconstruct traffic crashes and identify the appropriate solutions for enhancing traffic safety at horizontal curve segments in Vietnam.
Proposed severity ranking for ASTM E3303-21 protocol to quantify asphalt pavement cracking from automated 3D surveys
Authors: Nguyen Teron , Pin Kelvin Lee Yang , Tan Jun Yew , Ho Nyok Yong 
Published: August 2023

Abstract
Cracking is one of the essential indicators to evaluate pavement surface conditions; however, it is challenging to rate pavement cracking automatically from 3D digital images. Recently, a two-level automated crack rating system was proposed for pavement management in Singapore where Level 1 provides detailed crack information including cracking extent, types, and severity. Level 2 is a macro-indicator ranging from 0 to 5 based on crack extent over a 10-m length pavement section, with 0 being excellent condition and 5 being very bad condition. On the other hand, the new ASTM E3303-21 standard has introduced the Pavement Surface Cracking Metric which is a dimensionless measure equivalent to crack density and the Pavement Surface Cracking Index which provides ratings of pavement cracking ranging from 0 to 100, with 0 being the worst possible condition and 100 being the best possible condition. This study was conducted to compare and potentially bridge the gaps between the two mentioned cracking rating methods. Cracking data were collected from the Singapore road network using the Laser Crack Measurement System-2 (LCMS-2). Based on the study findings, three severity ranks (low, medium, and high) were proposed to facilitate the inclusion of the ASTM E3303-21 cracking protocol into Pavement Condition Index calculations.
Effects of PET and RFCC on the dynamic modulus, phase angle, and complex viscosity of asphalt concrete
Authors: Do Cao-Phan , Le Anh-Thang , Nguyen Manh-Tuan 
Published: August 2023

Abstract
With economic and social development, the total amount of domestic and industrial solid waste discharged is considerable. In 2020, Vietnam generated about 2.2 million tons of plastic waste and 2 million tons of industrial solid waste. And most of them are landfilled and take a long time to decompose. This has dramatically affected the environment, costly land resources, and considerable transportation, burial, and management costs of those landfills. Therefore, many scientists have studied to recycle these wastes. There are two approaches to using recycled waste in hot mix asphalt (HMA). Waste plastic changes the properties of the asphalt binder, and solid waste replaces coarse particles in an asphalt mixture. During the research on using recycled waste for asphalt concrete, PET (Poly Ethylene Terephthalate) and RFCC (Residue Fluid Catalytic Cracking) were chosen for the study. This paper presents a study on the influence of PET (with 0.2% content in HMA) and RFCC (with 5% content in HMA) on the viscoelastic property of asphalt concrete based on dynamic modulus, phase angle, and complex viscosity values. At high temperatures, HMA using PET and RFCC exhibit complete elastic behavior (φ ≈ 50) in contrast to the viscous elastic behavior of the control sample (φ ≈ 150). Compared control sample, RFCC significantly increased the stiffness of HMA at low and high temperatures; with the dynamic modulus of HMA using RFCC increased 1.1 times at low and 1.6 times at high temperatures; the viscosity of HMA using RFCC and PET decreased 10 times and 7 times at low temperatures.
Evaluating potential expansion and strength of compacted steel slag aggregates at different compaction density
Authors: Nguyen Cuong T. , Pham Phuong N. , Nam Huynh Phuong , Le Chau D. 
Published: August 2023

Abstract
Steel slag aggregates can be utilized as unbound materials for road bases or as fine/coarse aggregates in asphalt/cement paving concrete. However, the availability of free lime (f-CaO) in the materials is detrimental to volumetric stability, affecting the strength or durability of resulting paving products incorporating steel slag aggregates. This paper investigates the potential expansion of fine and coarse steel slag aggregates compacted at different compaction densities. The experimental results exhibited a higher stability of the coarse granular mixture exposed to water than the fine one. Also, more compaction increased expansibility in the fine mix, especially at high compaction density. Furthermore, the graded steel slag aggregate exhibited higher strength than the other aggregates. The findings provide reference information on the useability of steel slag in cement-based materials, like the replacement of coarse aggregate is better than the fine ones in volume stability of steel slag concrete.