bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Pyrolysis Temperature and Time on Properties of Palm Kernel Shell-Based Biochar
Authors: Mohd Hasan MH , Bachmann RT , Loh SK , Manroshan S , Ong SK 
Published: August 2019

Abstract
Pyrolysis is a thermal decomposition of biomass occurring in the absence of oxygen. Biochar (solid), bio-oil (liquid) and biogas (gas) are the typical products from pyrolysis of biomass. This endothermic process produced biochar with high carbon content. During pyrolysis, the material is heated up from ambient to a peak temperature and remains for a defined residence time. Therefore, the pyrolysis peak temperature and the residence time are the key parameters for pyrolysis. Studies on the effect of these parameters on the biochar characteristics and the pyrolysis products composition are numerous. However, there are limited findings of these parameters with palm kernel shell (PKS) as the biomass. This study focusses on the effect of the pyrolysis temperature and residence time of PKS on the yield of biochar produced and the biochar physio-chemical properties. The results showed that biochar yield decreased as the peak temperature and residence time increased. This finding is consistent with the findings by other researchers. However, those factors do not have distinct influence on biochar’s carbon content as found in other study which the peak temperature has the bigger impact instead of residence time. The effect of peak temperature or residence time on grindability; i.e. particle size of biochar after wet ball milled is insignificant. Smaller size of biochar may improve its function as reinforcing filler. As a conclusion, the optimum setup of pyrolysis is needed for a balance production in yield and biochar’s properties. It is recommended to produce biochar at higher peak temperature and shorter residence time to increase the total production. Additional analysis e.g. physical testing on the final polymer product can be used to investigate the effect of pyrolysis peak temperature and residence time.
Purification of Monomers Leads to High-Quality Lignin Macromonomers
Authors: Syed Azhar S.A.R. , Ahn Dong June 
Published: August 2019

Abstract
Purification is critical in any chemical process. The removal of impurities will produce the product in better quality and high standard. In this study, a new type of monomer was prepared by condensation polymerization of alkali lignin (AL) and methacryloyl chloride (MAC). The effect of AL/MAC ratio and the purification of MAC were investigated. The physical and chemical properties of the product obtained which is lignin methacrylate (LMA) were characterized by Fourier Transformed Infrared spectroscopy (FT-IR) and Nuclear Magnetic Resonance (1H-NMR). The result reveals that the purification was successfully removed the hydroxyl groups from the stabilizer in MAC and it is found that all the hydroxyl groups are coming from AL. The single interaction between AL and MAC has successfully enhanced the product obtain which does show no hydroxyl groups. The 1H-NMR data also showed that the purification of MAC influences the outcome. The noise and impurities were eliminated after the purification of MAC, and more pure products were obtained. This new monomer (LMA) synthesis that can be further utilized for various applications.
Numerical Simulation of the Reliability of In-Situ Eddy Current Testing Considering the Influence of Penetration Depth
Authors: Tian P Q , Zhan S Z , Feng Y W , Zhang X L , Xue X F 
Published: August 2019

Abstract
In order to study the reliability of in-situ eddy current testing, the factors affecting the in-situ eddy current detection and the signal response values are firstly determined. Then the numerical simulation model of eddy current detection is established by COMSOL, and the different values of the device and the tested structural are substituted into the simulation model to obtain the signal response value. Finally, the probability of detection (POD) curve is obtained by numerical simulation method based on function model. In this paper, based on the numerical simulation method of probability density function, the numerical simulation of eddy current testing reliability is formed. Through the in-situ eddy current testing reliability numerical simulation case, the detection probability of cracks in the structure is quantitatively affected by the penetration depth.
Identification of Key Conflict Nodes Based on Complex Network Theory
Authors: Jiawei Li , Xiangxi Wen , Libiao Zhang , Fei Liu 
Published: August 2019

Abstract
The current methods of detecting flight conflicts are difficult to grasp the overall conflict situation in the air, which is not conducive to the controllers to make accurate judgment on different conflict situations. In this paper, a method to identify key nodes of flight conflict based on complex network theory is proposed. Firstly, a conflict situation network model was built based on the ACAS protection area model. Then node degree centrality, closeness centrality and PageRank were used to evaluate the comprehensive importance of all nodes in the conflict situation network by AHP method. And we can find out the key conflict locations and conflict aircrafts based on the evaluation results of the index. The simulation results show that the model can effectively identify the key conflict aircrafts and positions in the airspace. And It can help controllers fully grasp the air security situation by classifing the air conflict situation levels.
Research on Height and Diameter of Doppler VHF Omnidirectional Beacon in Complex Environment
Authors: Fei Liang , Yue Hu , Yuankai Li 
Published: August 2019

Abstract
With the development of community around Doppler VHF omnidirectional beacon(DVOR), more and more DVORs are restricted, and even severely disabled. The DVOR’s counterpoise can be elevated to improve the coverage. But raising counterpoise will cause some problems such as null and worse bearing error. The paper research the lateral multipath, longitudinal multipath, height and diameter of counterpoise from the null, the first Fresnel zone, signal coverage, bearing error combing surrounding buildings and terrain, providing some technical means for improve or eliminate nulls and bearing error in construction of DVOR, and pre-evaluating whether it can pass the flight inspection after the completion of construction.
Long Time Integration for High Speed Target Detection Based on Radonkt-LVT
Authors: Chen Jie , Wu Qi , Zhang Yue , Chen Zengping 
Published: August 2019

Abstract
In this paper, a computationally efficient long-time integration and parameters estimation method via Keystone transform(KT), Radon Transform(RT) and Lv’s Transform(LVT) is proposed. Firstly, the KT-Radon is used to eliminate the range cell migration(RCM) of the echo after pulse compression, then using LVT to obtain the long-time integration and parameters estimation of high-speed target with acceleration motion. Compared with the GRFT algorithm, the proposed method only needs one dimensional search for range. Compared with the KT-FRFT algorithm, there is no need to search Doppler fold factor in this proposed method. So the proposed method doesn’t suffer from huge computation cost and obtain a good tradeoff between the computational cost and detection performance in comparison with the above algorithms. Finally, several experiments are provided to demonstrate the effectiveness of RadonKT -LVT.
A Fast and Collision Avoidance Distributed TDMA Schedule Based on the Multi-Arms Bandit
Authors: Zheng ChaoYi , Huang ShengChun , Li TaiLi 
Published: August 2019

Abstract
In this paper, we propose a novel distributed TDMA protocol based on the Multi-Arms Bandit model for the dynamic UAVs environment. Because of the frequent topology changes of UAVs, we consider a distributed communication protocol, which do not require the maintenance of accurate network topology information. Through the adaptive interaction between nodes, perceiving the surrounding topology environment and learning from historical experience, each node in the network can transmit information in a fast collision-free way. Also, the MAB model is utilized in our protocol, so that the time slot can obtain sufficient multiplexing rate through multiple rounds of node selection. Experiments show that the protocol can achieve better throughput and fast enough convergence speed, even in the case of high network density, and scales well with the size of the network.
A Modified KNN Indoor WiFi Localization Method With K-median Cluster
Authors: Lan Wei , Li Hongxin 
Published: August 2019

Abstract
Because of the serious attenuation and multi-path effect of GPS signal, outdoor-positioning technology can not be applied in complex indoor environment. Through the study of K-Nearest Neighbor applied in WiFi positioning, according to the problem that the time complexity of KNN algorithm increases linearly with the quantity of samples, this paper combined clustering algorithm with KNN optimized the similarity measure in fingerprint feature space and proposed a efficient indoor target location algorithm . Experimental results showed that the algorithm improved the positioning accuracy, had strong robustness to noise and more importantly, the positioning time was effectively shortened and it can meet the requirements of practical applications.
Electromagnetic Thermal Coupling Simulation Analysis of Silicon Carbide Shock Absorber
Authors: Xiaofang Yin , Xiaoning Liu , Jiayong Qin , Chunlin Du 
Published: August 2019

Abstract
This paper introduces a set of absorbing equipment used in 3.2GHz band vacuum high and low temperature environment. Through the finite element method modeling, COMSOL Multiphysics multi-physics simulation software analyzes the electromagnetic thermal coupling capability. The simulation results show that the absorbing properties of the silicon carbide pyramidal absorbing material are good. If the loss caused by the electrical conductivity of silicon carbide is considered, the absorbing performance of the silicon carbide pyramid will be greatly improved to -40dB. The simulation calculation model combines the electromagnetic field with the thermal, and gives the temperature curve and the isothermal contour dynamic diagram of the pyramid. It provides theoretical guidance for practical engineering applications.
Study on Sequent Test Effects of Atomic Oxygen/thermal Cycling
Authors: Zhai R Q , Tian D B , Jiang L X , Xia Y , Li X Y , Li Y 
Published: August 2019

Abstract
Two kinds of unidirectional laminates made from carbon/epoxy composite named M40/DFA-1 & M40/DFA-N3(nano TiO2 contained) are selected to study the different effects between different test sequences of atomic oxygen/thermal cycling. Based on the ground simulating test of atomic oxygen and thermal cycling, several kinds of tests and analysis are conducted, such as surface morphology observation, mass loss test, inter-laminar shear strength test, and X-ray photoelectron analysis of surface components. After the exposure of atomic oxygen and thermal cycling, surface erosions is observed on both of the materials, in addition, mechanical properties are both changed. It must be highlight that, under the condition of 1.5×1020 atoms/cm2 AO and 200 thermal cycles within the range of -150°C∼+150°C, different sequences lead to different results, either the extend or the tendency. In which, samples under AO+TC sequence exhibited relatively higher mass loss and erosion rate as well as more severe mechanical performance degradation.
Initialization Method of Nozzle Flow Field Based on One-Dimensional Isentropic Theory and the Study of Its Application
Authors: Zhao HaiLong , Peng Ke , Zhang WeiHua , Fan YuZhu , Jie JinLiang 
Published: August 2019

Abstract
The two-dimensional axisymmetric nozzle is initialized by two methods which are the hybrid initialization method of the commercial computational fluid dynamics software Fluent and the initialization program based on the one-dimensional isentropic theory. The first-order upwind format is combined with the SA model to solve the two-dimensional axisymmetric nozzle under the same boundary conditions. The convergence process is obtained in the process of numerical calculation, and the influence of two different initialization methods on the convergence process is analysed. The results show that the initialization method based on the one-dimensional isentropic theory effectively improves the convergence of the nozzle numerical model calculation process, accelerates the convergence speed and improves the calculation efficiency.
Research on Safety Risk Evolution of Military Aviation System Based on ANP-SD
Authors: Wang Qiang , Liu Qiuhan , Xia Ruicong , Huang Yingjie 
Published: August 2019

Abstract
With the development of equipment, the complexity of China’s military aviation system continues to increase. The system risk is transformed from the initial independent risk factor to the cross-influence risk factor, which makes the system risk control difficult. In order to maintain the safety level of military aviation system, the factors affecting the safety level of the system are analysed from five aspects: personnel, machine, environment, management and logistics. The analytic hierarchy process (ANP) is used to construct the model of the system risk factors and the system dynamics method is used to establish the risk evolution simulation model, and quantitatively analyse the sensitivity of risk factors to explore the basic rule of risk evolution.
Application of Fault Diagnosis Expert System for Unmanned Vehicle Safety
Authors: Chen ChunPing , Zhang Lin , Wang Jie , Zhang Jie 
Published: August 2019

Abstract
In order to ensure the safety of the underwater unmanned vehicle (UUV) and reduce the risk of damage or loss during operation, the safety system will be equipped on the UUV. It can accurately locate the fault when the submersible encounters dangerous situations, such as equipment failure and cabin flooding, assess the dangerous situation and make emergency measures, so as to help the underwater unmanned submersible realize self-rescue. Fault diagnosis expert system is a knowledge-based fault diagnosis method, which is suitable for complex systems with incomplete knowledge. However, because the working environment of the underwater unmanned underwater vehicle is very complex and the fault types are diverse and change in real time, the traditional fault diagnosis expert system may not meet the response time requirements of the safety system due to the long response time required. Therefore, the finite state machine technology is applied to the diagnostic expert system to improve the response speed of the diagnostic expert system, and at the same time make the system more flexible and convenient to expand its functions. In addition, the model-based design method was applied to establish the model of the security system in stateflow, and the model verification was carried out. With the help of PLC Coder tool, the code of the target controller was generated and the algorithm was deployed.
Structural Design and Difficulties of Solar UAV
Authors: Zhang W W , Zhang L G , Yan Z W , Wang L 
Published: August 2019

Abstract
The design of high-altitude and long-endurance solar aircraft is obviously different from that of conventional aircraft. Its unique energy system and operating conditions make it necessary to carefully weigh the key technical details in design. The structure has a great influence on the endurance performance of solar aircraft. The structure weight can be roughly estimated by the proportion of the airborne energy system to the total weight of the aircraft, so as to optimize the structure. Through the analysis of several typical solar aircraft, it can be concluded that the aerodynamic layout and structure design have a great impact on the flight time and performance of solar aircraft. Finally, the challenges faced by solar aircraft are presented, which can provide reference for the design of solar aircraft in the future and help.
Research on the Variation Analysis Model for CFRP Assembly
Authors: Yu Jianfeng , Huang Shuhan , Zhang He 
Published: August 2019

Abstract
The conventional error analysis model is based on Key Characteristics (KC) tree [1] and the nominal 3D assembly model. Before the actual execution of assembly process, the potential interferences and out-of-tolerance problems are simulated and predicted. Then the tolerance and assembly schemes of the parts are optimized accordingly. This method requires statistical deviation data of parts and it can only give a rough probability for mass production case. In this paper, the common CAT technologies, variation analysis and optimization method are presented with an example of wing box model in 3DCS. Based on KC tree and optimizing theories a model analysis method is proposed to improve the performance in the case of multi-material part assembly processes.
Human Interface Research of Civil Aircraft Cockpit Based on Touch Control Technology
Authors: Yang Wen , Sun Qin , Gao Xiaolong , Dong Dayong , Ma Xianchao 
Published: August 2019

Abstract
Touch screen technology is an important direction of the aircraft cockpit technology development. More and more touch screen test units are applied in the cockpit. However, most of the touch screen interface design is only a simple copy of the physical interface, which does not bring any benefits to the aircraft, but will cause some safety effects. Fundamentally speaking, these test units did not consider the impacts of flight crew operating procedures, human factors, flight scenes, and other factors on touch screen technology. This paper gives some advantages and disadvantages analysis for the touch control technology and provides a new concept of cockpit overhead control panel based on the touch control technology. The overhead touch control panel can not only effectively reduce the workload of the pilot, reduce the weight of the system, but also ensure the same flight safety with the physical panel. Keywords. Touch Control, Human Factor, Workload, Hybrid Layout, Ergonomics Evaluation.
A CAS Message Simulation Module Used in Civil Aircraft for Air Management System Failure Diagnosis
Authors: Haiyan Xi 
Published: August 2019

Abstract
Air management system is one of the most important airborne systems on civil aircraft, which is responsible for controlling aircraft bleed air, cabin pressure control, wing anti-icing, cabin ventilation and temperature control. And the air management control system is the brain and neural network of the entire air management system. The air management control system control the various subsystems of the air management system and control the air management system to work together with other interfaced systems. Air management system control logic and interface signals are the key points and most difficulty parts in air management system control. For this highly complex system, failure diagnosis is most important and difficult part in ground test and flight test. Usually faults are reflected on the CAS message and synoptic pages as the alarms. However, the causes of such alarms may be varied. The traditional trouble shooting approach is to check the control specification documents which are complicated and hard to find the root cause. If there is a CAS message simulation module database that can be quickly traced back to the trigger logic of any one of the alarms, and the signal relationship between the alarms is displayed, the control logic of the system is clearly displayed, the failure diagnosis would became simple and intuitive. Based on the above design intention with referring to control specification, this paper created a set of air management system alarm models by using Matlab/Simulink. These alarm models are used for system troubleshooting and design’s optimization. Finally, an application of cabin pressure control alarm with both trouble shooting and optimization is introduced.
Corrosion Detection for Large Steel Structure base on UAV Integrated with Image Processing System
Authors: Chen Qingcheng , Wen Xiang , Lu Shujie , Sun Dongxiao 
Published: August 2019

Abstract
Large cranes and other outdoor large steel structures need to be checked regularly to ensure their safety, and corrosion detection is one of the most important inspection item. Traditional manual inspection has many disadvantages including high labour intensity, low efficiency and low detection accuracy. In this paper, a novel corrosion detection method based on UAV intelligent image recognition is proposed. The six-rotor UAV can collect the photos of the steel structure device safely and reliably. With the intelligent corrosion recognition algorithm proposed in this paper, infection such as background noise can be eliminated, and the corrosion area in the image can be identified automatically with high precision. A test device has been built and the results show that the device and method can identify the corrosion area effectively.
Mechanism and Characteristics of High-Frequency Pulsed Jet Circulation Control
Authors: Zhan Ren , Zhang Deng-cheng , Zhang Yan-hua , Zheng Wu-ji , Li Yi-wen 
Published: August 2019

Abstract
Conventional circulation control technology presents problems in certain situations. Pulsed jet circulation control appears to be a feasible alternative to solve such problems, especially for the high-frequency pulsed jet (HFPJ). To acquire the aerodynamic characteristics of the HFPJ and reveal the mechanism behind it, numerical simulation is conducted using a verified computational fluid dynamics (CFD) method. The action mode of the pulsed jet characterized by equilibrium and oscillation is proposed according to the analysis of a dynamic procedure. Lift and drag characteristics are obtained, defining the critical frequency to demarcate high and low frequencies. An oscillation function is also established to illustrate the difference between the characteristics of the HFPJ and a low-frequency pulsed jet (LFPJ) by analyzing the simulation results. The pressure distribution and flow field in the simulation results explain the stall characteristic of the HFPJ. Series results indicate the HFPJ demonstrates superior lift augmentation and drag reduction compared to the LFPJ and steady jets.
Mission Capability Assessment of 3D Printing Cubesats
Authors: Chen Zhiyong , Zosimovych Nickolay 
Published: August 2019

Abstract
With the successful development of integrated technologies, many spacecraft subsystems have been continuously miniaturized, and CubeSats have gradually become the main executors of space science exploration missions. It is a new challenge to combine the CubeSat design with 3D printing. Compared with traditional manufacturing through machining, 3D printing technology has several advantages including short period of manufacturing, high accuracy in manufacturing small parts and low cost. The research task of this paper is a LEO (Low Earth Orbit) CubeSat mission, with a maximum acceleration of 5 g during the launch process, the internal operating temperature range of the CubeSat is from 0 to 40 °C, external temperature from -80 to 100 °C. The environmental factors were fully considered in the CubeSat design process, the impact load received during the CubeSat launch process and the working environment after reaching orbit were simulated and analyzed by ANSYS after the design parameters were obtained to verify the feasibility of the design.