Asbestos Exposure during Gasket Removal from Aircraft Engine

We have previously evaluated asbestos exposure associated with various maintenance procedures on light aircraft. The purpose of this study was to evaluate asbestos exposure during engine maintenance on light aircraft. This test was designed to evaluate the potential for asbestos exposure to mechanics and others who remove asbestos-containing engine gaskets from reciprocating style aircraft engines. Utilized in this test was an air cooled, horizontally opposed, aviation gasoline burning engine, assembled during 1986 and operated intermittently up into 2015, having accumulated 1680 hours run time. Nearly 75% of the asbestos-containing gaskets installed during 1986 were still in place at the time of testing. Chrysotile asbestos contents of such gaskets ranged from 55% to 60% by area, for those of sheet style and 5% by area, for the spiral wound metal/asbestos style. Despite the levels of effort required to effect gasket removals, the professional aircraft mechanic was not exposed to airborne asbestos fibers at the lower limits of sampling and analytical detection achieved;all of which were substantially less than the current Occupational Safety and Health Administration Permissible Exposure Limits for asbestos. The results of this testing indicate an absence of gasket related asbestos exposure risk to mechanics who work with light aircraft engines, including those having asbestos-containing gaskets. These results are consistent with the findings of Mlyarek and Van Orden who studied the asbestos exposure risk occasioned during overhaul of larger radial style reciprocating aircraft engines [1].

The Model of“Post,Course,Competition,Certificate”Integrated Education for Electronic Information Engineering Technology Major in Higher Vocational Colleges

The core education function of higher vocational colleges is to train technical talents with high quality,so as to meet the needs of talents in the development stage of our society.Under the guidance of talent training,higher vocational colleges need to pay attention to establishing an all-round and three-dimensional education model,and promote innovation of higher vocational education on the basis of this.It is also a way to promote the innovation of higher vocational education to vigorously promote the construction of“post,course,competition,certificate”mode in the construction of education mode.Through the construction of“post,course,competition,certificate”mode,the education mode of higher vocational colleges is gradually improved,so as to strengthen the effectiveness of talent training in higher vocational colleges.Therefore,in this paper,the author puts forward some suggestions to promote the construction of the integrated education mode of the electronic information engineering technology major in higher vocational colleges,so as to help improve the talent training level of higher vocational colleges.

An Exploratory Practice of Integration of Industry and Education in High-level Programming Language Course in the Background of New Engineering

This paper analyzes some problems of the current teaching situation in the course High-level Programming Language,such as the lagging content of the course compared with technology development,the emphasis on theory rather than on practice,the low enthusiasm of students for learning,and the weak practical ability of students.In response to the needs of enterprises for talents under the background of New Engineering,especially the cultivation of students’adaptability and practical abilities towards future industries to improve students’knowledge and problemsolving abilities to keep up with the modern technology,this paper proposes the ways and methods to reform and explore the teaching content and teaching methods by integrating industry and education,assisting teaching according to industrial demands,and lowering technology barriers of new technology.The practical effect is evaluated through a survey in class and the follow-up questionnaire after class,and the results show that the effect of the practice is effective.

Research on the Construction of a Landscape Engineering Teaching Resource Library Under the“4321”Industry-Education Integration System

This paper studies and explores the construction of a teaching resource library for landscape engineering under the“4321”industry-education integration system,focusing on the construction objectives,construction paths,and construction contents,aiming to open-up the channel of school-enterprise cooperation,improve enterprise participation,and promote the reform of teaching mode and teaching methods.Establishing a practical resource library will connect and integrate students,teachers,and enterprises.A complete library of landscape-oriented teaching resources will be constructed according to the talent portraits of the industry to open-up the relationship between upstream and downstream courses,and further improve the precise fit between the cultivation of applied undergraduate talents and enterprises.

The Effect of Ignition Parameters on the Combustion Characteristics of an Aviation Piston Engine

A cylinder combustion simulation model was established for a two-stroke aviation piston engine used in a small unmanned aerial vehicle. The influence of different ignition system parameters on the combustion process of aviation kerosene was studied using this model. The research results showed that under the working conditions of 5500 r/min and 50% throttle opening, as the ignition energy increased, the peak values of average cylinder pressure and average temperature increased, and the combustion duration shortened, The advance of the combustion center of gravity increases the tendency of the engine to knock. Under the same operating conditions, as the ignition timing advances, the peak values of average pressure and average temperature in the cylinder increase, gradually approaching the top dead center, and the tendency of engine detonation increases more significantly.

Integrated Computational Materials Engineering for the Development and Design of High Modulus Al Alloys

Integrated computational materials engineering(ICME)is to integrate multi-scale computational simulations and key experimental methods such as macroscopic,mesoscopic,and microscopic into the whole process of Al alloys design and development,which enables the design and development of Al alloys to upgrade from traditional empirical to the integration of compositionprocess-structure-mechanical property,thus greatly accelerating its development speed and reducing its development cost.This study combines calculation of phase diagram(CALPHAD),Finite element calculations,first principle calculations,and microstructure characterization methods to predict and regulate the formation and structure of composite precipitates from the design of highmodulus Al alloy compositions and optimize the casting process parameters to inhibit the formation of micropore defects in the casting process,and the final tensile strength of Al alloys reaches420 MPa and Young's modulus reaches more than 88 GPa,which achieves the design goal of the high strength and modulus Al alloys,and establishes a new mode of the design and development of the strength/modulus Al alloys.

Engineering practices for the integration of large-scale renewable energy VSC-HVDC systems

With the continuous development of power electronic devices,intelligent control systems,and other technologies,the voltage level and transmission capacity of voltage source converter (VSC)-high-voltage direct current (HVDC) technology will continue to increase,while the system losses and costs will gradually decrease.Therefore,it can be foreseen that VSC-HVDC transmission technology will be more widely applied in future large-scale renewable energy development projects.Adopting VSC-HVDC transmission technology can be used to overcome issues encountered by large-scale renewable energy transmission and integration projects,such as a weak local power grid,lack of support for synchronous power supply,and insufficient accommodation capacity.However,this solution also faces many technical challenges because of the differences between renewable energy and traditional synchronous power generation systems.Based on actual engineering practices that are used worldwide,this article analyzes the technical challenges encountered by integrating large-scale renewable energy systems that adopt the use of VSC-HVDC technology,while aiming to provide support for future research and engineering projects related to VSC-HVDC-based large-scale renewable energy integration projects.

Feature Based Machining Process Planning Modeling and Integration for Life Cycle Engineering

Machining process data is the core of computer aided process planning application systems.It is also provides essen- tial content for product life cycle engineering.The character of CAPP that supports product LCE and virtual manufacturing is an- alyzed.The structure and content of machining process data concerning green manufacturing is also examined.A logic model of Machining Process Data has been built based on an object oriented approach,using UML technology and a physical model of machin- ing process data that utilizes XML technology.To realize the integration of design and process,an approach based on graph-based volume decomposition was apposed.Instead,to solve the problem of generation in the machining process,case-based reasoning and rule-based reasoning have been applied synthetically.Finally,the integration framework and interface that deal with the CAPP integration with CAD,CAM,PDM,and ERP are discussed.

An Internet-enabled Integration of Concurrent Engineering with Co-design

In this paper,the Web-based integration methodology and framework have been developed to facilitate collabora- tive and concurrent engineering design in distributed manufacturing environments.The distributed concurrent engineering and co- design are discussed as key components in the mechanism.The related integration system is presented,which includes four function- al modules:co-design,Web-based visualization,manufacturing analysis and look-up service.It can be used for a design team geo- graphically distributed to organize a collaborative and concurrent engineering design effectively.In particular,the collaborative mechanism incorporated with Java-based and Internet-enabled technologies can generate extended strategies for design and planning. Thus,the proposed integration architecture enables the system to be generic,open and scalable.Finally,for the trend of global manufacturing,a case study of Internet-enabled collaborative optimization is introduced and a discussion on teamwork capability is made.

A CORBA-Based Integration Platform of Product Development Process Management for Concurrent Engineering

Product development process management plays an important role in concurrent engineering (CE). The integration platform is a useful tool for effectively supporting the software development and integration. Based on the analysis of practical requirements for product development process management for CE, a CORBA-based integration platform of product development process management (IP-PDPM) is designed and developed. The design principles for IP-PDPM are described. The system architecture and functions of the platform are given, the key technologies for the implementation of IP-PDPM are presented, the application integration mechanism and its implementation techniques are also detailed.

Analysis on the Talent Training Mode of Management Science and Engineering from the Perspective of Multidisciplinary Integration

In today’s era,multidisciplinary integration is the development trend of education,which breaks the field of a single discipline and lays the foundation for the development of education.Objectively speaking,with the integration of disciplines,a new interdisciplinary is formed.This new discipline is comprehensive and systematic;in addition,it integrates knowledge,technology,and methods.It is the result of the collision of different disciplines.As an applied course,Management Science and Engineering integrates multidisciplinary knowledge,such as science and technology,information science,and mathematics.Its main purpose is to solve various problems in social and economic development.It has a long-term impact on the development of contemporary multidisciplinary education.In the new era,in order to meet the requirements of social and economic development,the teaching of Management Science and Engineering should be based on the perspective of multidisciplinary integration,combined with the current characteristics and training mode of the discipline,explore new talent training paths,and then drive the development of the whole industry.

Vertical Integration and Reverse Engineering of Agricultural Enterprises

This paper studies the potential effects of agricultural enterprise's vertical integration and reverse engineering on downstream firms.Suppliers who invest reverse engineering technology can exploit customer's information. An integrated supplier can obtain at no cost the information from its subsidiary. Based on repeated game and considered corporate " good" or " bad" type,this paper analysis supplier's selection and downstream investment in innovation. The results showed that: when the cost is higher than the threshold value no company invest in reverse engineering,when the cost is lower than the threshold value the integration company invest in reverse engineering; in the second period,vertical integration reduce the downstream independent enterprise's innovation investment and profits,integrated enterprise increase innovation investment and profits; during the first period of the game,the independent downstream firms being " completely foreclosure".

An efficient method for train-track-substructure dynamic interaction analysis by implicit-explicit integration and multi-time-step solution

In this work,a method is put forward to obtain the dynamic solution efficiently and accurately for a large-scale train-track-substructure(TTS)system.It is called implicit-explicit integration and multi-time-step solution method(abbreviated as mI-nE-MTS method).The TTS system is divided into train-track subsystem and substruc-ture subsystem.Considering that the root cause of low effi-ciency of obtaining TTS solution lies in solving the alge-braic equation of the substructures,the high-efficient Zhai method,an explicit integration scheme,can be introduced to avoid matrix inversion process.The train-track system is solved by implicitly Park method.Moreover,it is known that the requirement of time step size differs for different sub-systems,integration methods and structural frequency response characteristics.A multi-time-step solution is pro-posed,in which time step size for the train-track subsystem and the substructure subsystem can be arbitrarily chosen once satisfying stability and precision demand,namely the time spent for m implicit integral steps is equal to n explicit integral steps,i.e.,mI=nE as mentioned above.The numeri-cal examples show the accuracy,efficiency,and engineering practicality of the proposed method.

Aircraft Engine Gas Path Fault Diagnosis Based on Hybrid PSO-TWSVM

Twin support vector machine(TWSVM)is a new development of support vector machine(SVM)algorithm.It has the smaller computation scale and the stronger ability to cope with unbalanced problems.In this paper,TWSVM is introduced into aircraft engine gas path fault diagnosis.The generalization capacity of Gauss kernel function usually used in TWSVM is relatively weak.So a mixed kernel function is used to improve performance to ensure that the TWSVM algorithm can better balance a strong generalization ability and a good learning ability.Experimental results prove that the cross validation training accuracy of TWSVM using the mixed kernel function averagely increases 2%.Grid search is usually applied in parameter optimization of TWSVM,but it heavily depends on experience.Therefore,the hybrid particle swarm algorithm is introduced.It can intelligently and rapidly find the global optimum.Experiments prove that its training accuracy is better than that of the classical particle swarm algorithm by 5%.

Numerical Analysis and Verification of the Gas Jet from Aircraft Engines Impacting a Jet Blast Deflector

The process of the gas jet from aircraft engines impacting a jet blast deflector is not only a complex fluid–solid coupling problem that is not easy to compute, but also a safety issue that seriously interferes with flight deck envi?ronment. The computational fluid dynamics(CFD) method is used to simulate numerically the impact e ect of gas jet from aircraft engines on a jet blast deflector by using the Reynolds?averaged Navier?Stokes(RANS) equations and turbulence models. First of all, during the pre?processing of numerical computation, a sub?domains hybrid meshing scheme is adopted to reduce mesh number and improve mesh quality. Then, four di erent turbulence models includ?ing shear?stress transport(SST) k-w, standard k-w, standard k-ε and Reynolds stress model(RSM) are used to compare and verify the correctness of numerical methods for gas jet from a single aircraft engine. The predicted values are in good agreement with the experimental data, and the distribution and regularity of shock wave, velocity, pressure and temperature of a single aircraft engine are got. The results show that SST k?w turbulence model is more suitable for the numerical simulation of compressible viscous gas jet with high prediction accuracy. Finally, the impact e ect of gas jet from two aircraft engines on a jet blast deflector is analyzed based on the above numerical method, not only the flow parameters of gas jet and the interaction regularity between gas jet and the jet blast deflector are got, but also the thermal shock properties and dynamic impact characteristics of gas jet impacting the jet blast deflector are got. So the dangerous activity area of crew and equipments on the flight deck can be predicted qualitatively and quantitatively. The proposed research explores out a correct numerical method for the fluid–solid interaction during the impact process of supersonic gas jet, which provides an e ective technical support for design, thermal ablation and structural damage analysis of a new jet blast deflector.

DID Code:A Bridge Connecting the Materials Genome Engineering Database w让h Inheritable Integrated Intelligent Manufacturing

A data identifier(DID)is an essential tag or label in all kinds of databases—particularly those related to integrated computational materials engineering(ICME),inheritable integrated intelligent manufacturing(I3M),and the Industrial Internet ofThings.With the guidance and quick acceleration of the developme nt of advanced materials,as envisioned by official documents worldwide,more investigations are required to construct relative numerical standards for material informatics.This work proposes a universal DID format consisting of a set of build chains,which aligns with the classical form of identifier in both international and national standards,such as ISO/IEC 29168-1:2000,GB/T 27766-2011,GA/T 543.2-2011,GM/T 0006-2012,GJB 7365-2011,SL 325-2014,SL 607-201&WS 363.2-2011,and QX/T 39-2005.Each build chain is made up of capital letters and numbers,with no symbols.Moreover,the total length of each build chain is not restricted,which follows the formation of the Universal Coded Character Set in the international standard of ISO/IEC 10646.Based on these rules,the proposed DID is flexible and convenient for extendi ng and sharing in and between various cloud-based platforms.Accordingly,classical two-dimensional(2D)codes,including the Hanxin Code,Lots Perception Matrix(LP)Code,Quick Response(Q.R)code,Grid Matrix(GM)code,and Data Matrix(DM)Code,can be constructed and precisely recognized and/or decoded by either smart phones or specific machines.By utilizing these 2D codes as the fingerprints of a set of data linked with cloud-based platforms,progress and updates in the composition-processing-structure-property-performance workflow process can be tracked spontaneously,paving a path to accelerate the discovery and manufacture of advanced materials and enhance research productivity,performance,and collaboration.

Prediction of Aircraft Engine Health Condition Parameters Based on Ensemble ELM

In view of aircraft engine health condition parameters prediction,an ensemble ELM based prediction approach is proposed in this paper. In the approach,the AdaBoost. RT algorithm is improved to adjust its threshold adaptively,and is utilized as the basic framework to establish the ensemble learning model using ELM as weak learners. The proposed approach is evaluated through the prediction of the actual engine fuel flow deviation time series,and the results demonstrate that this approach is feasible for the prediction of aircraft engine health condition parameters. The performance of the proposed approach is compared with single ELM, single process neural network ( PNN) ,and a similar ensemble ELM based approach using AdaBoost. RT as basic framework. The results show that,the proposed approach is more accurate than single ELM and single PNN,and no worse than the ensemble prediction approach for contrast,furthermore,the given approach is more convenient for practical application. Therefore,the proposed approach is better suited to the prediction of aircraft engine health parameters.

A Generative Adversarial Nets Method for Monitoring Data Generation on Aircraft Engines

A sufficient sample size of monitoring data becomes a key factor for describing aircraft engines state.Generative adversarial nets(GAN)can be used to expand the sample size based on the existing state monitoring information.In the paper,a GAN model is introduced to design an algorithm for generating the monitoring data of aircraft engines.This feasibility of the method is illustrated by an example.The experimental results demonstrate that the probability density distribution of generated data after a large number of network training iterations is consistent with the probability density distribution of monitoring data.The proposed method also effectively demonstrates the generated monitoring data of aircraft engine are in a reasonable range.The method can effectively solve the problem of inaccurate performance degradation evaluation caused by the small amount of aero?engine condition monitoring data.

THE ENGINEERING PREDICTION FOR AIRCRAFT NOISE

The acoustic emission from an aircraft during the flight is a dynamic process. The emitting acoustic power and received mean square acoustic pressure are functions of time. The paper deals with this problem as a quasi-steady one. The whole process is resolved into several elementary procedures, for example, the flight trajectory, the geometric relation between the noise sources and observers, the noise source characteristics, the air propagation and ground effect. Two calculation examples are given in the paper, one for a long-range passenger with high bypass-ratio turbofan engine, and the other for a 3-leaved propeller. The composition of aircraft noise, its time history, frequency spectrum and directivity can be clearly described by these curves. It may be useful for the designer to perform the acoustic design of his aircraft layout.

Ensemble Recurrent Neural Network-Based Residual Useful Life Prognostics of Aircraft Engines

Residual useful life(RUL)prediction is a key issue for improving efficiency of aircraft engines and reducing their maintenance cost.Owing to various failure mechanism and operating environment,the application of classical models in RUL prediction of aircraft engines is fairly difficult.In this study,a novel RUL prognostics method based on using ensemble recurrent neural network to process massive sensor data is proposed.First of all,sensor data obtained from the aircraft engines are preprocessed to eliminate singular values,reduce random fluctuation and preserve degradation trend of the raw sensor data.Secondly,three kinds of recurrent neural networks(RNN),including ordinary RNN,long shortterm memory(LSTM),and gated recurrent unit(GRU),are individually constructed.Thirdly,ensemble learning mechanism is designed to merge the above RNNs for producing a more accurate RUL prediction.The effectiveness of the proposed method is validated using two characteristically different turbofan engine datasets.Experimental results show a competitive performance of the proposed method in comparison with typical methods reported in literatures.