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General aviation aircraft has a wide range of applications, and effective cost management is one of the hot spots in the research of general aviation manufacturers. The purpose of this paper is to build a flexible engineering method to predict maintenance cost of general aviation aircraft.

To establish a reasonable general aviation aircraft maintenance cost prediction model, it is necessary to analyze the influencing factors and extract the main components of maintenance cost. The maintenance cost is divided by engineering method, and the estimation model of each component cost is established. Then, the general aviation aircraft maintenance cost model is obtained. The results show that the relative error of this method is between 13% and 20%, which has a good estimation accuracy and can be effectively used to estimate the maintenance cost of general aviation aircraft.

The maintenance cost plays an important role in the life cycle cost of general aviation aircraft. Accurate cost prediction method is of great significance to the optimal design of general aviation aircraft. However, there are few prediction models suitable for maintenance cost, the proposed approach is meaningful and quite desirable.

To some extent, this method overcomes the shortage of the work on maintenance cost prediction for general aviation aircraft. The model established in this paper has certain generality, which can provide some reference for general aviation aircraft design and operation enterprises.

This paper aims to find a new method that could be applied to the high and mid-grade prosthesis knee joint.

Based on analysis, calculation, modeling, simulation and experimental study of the motion law of knee joint, this paper not only determines the structure and parameters of the knee joint and calculates the instantaneous center but also analyzes the stance stability and completes the optimization. With the help of experimental tests (fatigue test and gait curve test), the quality and performance of the designed knee joint is verified.

The experimental results show that the gait curve of the designed knee joint is much closer to health people. The designed prosthesis knee joint, with adjustable swing speed and gait curve which are close to health limb, has a better performance when compared to the ordinary knee joint with four-bar linkage structure.

This paper developed a prosthesis knee joint based on a novel design method that could be applied to the “high and mid” grade prosthesis knee joint and verified its function on an amputee performed the lower amputation, which could provide theoretical support for researches and designs related to prosthesis knee joint in future.

Applying the theory of work adjustment (TWA), the purpose of this paper is to investigate whether the effect of hierarchical plateau on the turnover intention of employees at the career establishment stage is mediated by job satisfaction and moderated by person-job fit.

A survey method was used and data were collected from 248 Chinese employees at the career establishment stage. Hierarchical regression analysis and moderated mediation analysis were used to test the hypotheses.

The results demonstrated that hierarchical plateau was positively related to the turnover intention of employees at the career establishment stage and that job satisfaction played a mediating role in the relationship. Person-job fit moderated the relationship between hierarchical plateau and job satisfaction, and the indirect effect of hierarchical plateau on turnover intention via job satisfaction.

This research offers new insights into the links between hierarchical plateau and employees’ work attitudes and withdrawal behaviour within the TWA. The results suggest that managers can lessen the negative effects of hierarchical plateau on employees’ attitudes and withdrawal behaviour by improving employees’ overall person-job fit.

The purpose of this paper is to propose an adjustable oil film thickness test rig for detecting lubrication characteristics of the slipper. The mathematical analysis of lubrication is introduced. Based on the results from the test rig, the results comparison from test rig and mathematical analysis is carried out.

This paper introduces a mechanism which can adjust the oil film thickness between the slipper and swash-plate. Feasibility is ensured, and the accuracy of test rig is guaranteed by the three-coordinate measuring machine. Three displacement sensors show the oil film thickness and its shape. The reacting force and torque resulting from oil film can be achieved by three S-type force sensors and a torque sensor, respectively.

The relative error of the reacting force is small. The relative error reduces and is acceptable when the deformation of retainer is taken into account. The thickness and tilt angle of oil film have less effect on the reacting force. However, they are significantly impact on torque.

The test rig proposed in this paper is able to adjust the oil film thickness, which is used to detecting the lubrication characteristics in pump design.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2020-0166/

This paper proposes the lubrication characteristics of the worn slipper in the slipper–swashplate pair. The mathematical analysis of lubrication characteristics of slipper with the measured surface roughness distribution is introduced. Based on the results from the test rig, it carries out the result compassion in different operating conditions.

This paper introduces the measured surface roughness distribution of new and used slippers and generates the oil film thickness distribution with it. An average flow Reynolds equation of the pressure distribution is introduced too. The experimental results are carried out on a novel adjustable oil film thickness test rig.

The surface roughness of the worn slipper enlarges the reacting force and torque only if the oil film thickness is small. When the ratio of oil film thickness to the root mean square of surface roughness is much smaller than 3, the influence of it on torque is obvious.

Different surface roughness of worn slipper proposed in this paper has an influence on the lubrication characteristics. As the slipper is worn after a period of use, the changed lubrication characteristics should be considered in the slipper design.

This paper aims to propose the slipper/swash plate pair loaded with a step motor-spring mechanism to reduce the energy consumption under different rotating rate conditions. The relationship between the operating conditions, oil film thickness and energy consumption is analyzed. The system dynamic model of the slipper/swash plate pair loaded with a step motor-spring mechanism is introduced. Based on the results of the experiment, the PI controller and step motor-spring mechanism are useful for reducing energy consumption.

This paper introduces the energy consumption of the slipper/swash plate pair. A system dynamic model of the slipper/swash plate pair loaded with a step motor-spring mechanism is introduced too. In the experiment, three step motor and S-type force sensor are used to control the oil film thickness.

PI controller and the step motor-spring mechanism are useful for controlling the oil film thickness and reducing the energy consumption under different rotating rate conditions. The accuracy of the oil film thickness control is acceptable and the response time is a bit long

PI controller and the step motor-spring mechanism are useful for controlling the oil film thickness and reducing the energy consumption under different rotating rate conditions. The accuracy of the oil film thickness control is acceptable and the response time is a bit long.

The paper aims to extend the knowledge base for design and optimization of Star grain which is well known for its simplicity, reliability and efficiency. Star grain configuration is considered to be among the extensively used configurations for the past 60 years. The unexplored areas of treatment of ballistic constraints, non-neutral trace and freedom from use of generalized design equations and sensitivity analysis of optimum design point are treated in detail to bridge the gap. The foremost purpose is to expand the design domain by considering entire convex Star family under both neutral and non-neutral conditions.

This research effort optimizes Star grain configuration for use in Solid Rocket Motors with ballistic objective function (effective total impulse) and parametric modelling of the entire convex Star grain family using solid modelling module. Internal ballistics calculations are performed using equilibrium pressure method. Optimization process consists of Latinized hypercube generated initial population and Swarm Intelligence optimizer’s ability to search design space. Candidate solutions are passed to solid modelling module to simulate the burning process. Optimal design points, critical geometrical and important ballistic parameters (throat diameter, burn rate, characteristic velocity and propellant density) are then tested for sensitivities through Monte Carlo simulation.

The proposed approach takes the design of Star grain configuration to a new level with introduction of parametric modelling and sensitivity analysis, thus, offering practical optimum design points for use in various mission scenarios. The proposed design and optimization process provides essential data sets which can be useful prior to the production of large number of solid rocket motors. Results also advocate the adequacy of design from engineering perspective and practicality.

Results showed that few design parameters are sensitive to uncertainties. These uncertainties can be investigated in future by a robust design method.

Monte Carlo simulation can prove to be vital considering the production of a large number of motor units and enlightens the necessity to obtain statistical data during manufacturing.

This paper fulfils long-sought requirement on getting free from use of generalized set of equations for commonly used Star grain configurations.

This paper explores perspectives of elite female athletes competing at world championship sports events, hosted in extreme climatic conditions. From the athlete perspective, it examines the implications of decisions by global sports federations when selecting host cities and the subsequent impacts upon elite athletes competing in unfavourable climates.

Using an exploratory case study approach at the 2019 IAAF World Athletics Championships in Doha, Qatar, this paper explores insider perspectives of four elite female participants competing in the Marathon. Adopting the “elite interviewing” technique, and based on event participant experiences, the paper prioritises the perspective and “voice” of the athlete.

Four key themes emerged from the data. These were (1) the importance of training and preparation; (2) unique challenges of competition day; (3) elite athlete retrospection; and (4) prioritising the perspectives of elite athletes at international sports events. The findings highlight the challenges of managing athlete preparation and performance at world championship events hosted in extreme climatic conditions.

The sample size for this study whilst relatively small is unique. This reflects challenges accessing elite athletes, their reluctance to be interviewed, and the small pool of elite athlete talent available. Given these practical barriers, this represents a good sample size.

This paper secures unique insider access to elite level female endurance athletes competing at world championship events. The study makes a contribution to knowledge in event studies by introducing concepts of “elite event interviewing” and the “athlete-event paradox”.