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The purpose of this paper is to propose a new deep learning-based model to carry out better maintenance for naval propulsion system.

This model is constructed by integrating different deep learning algorithms. The basic idea is to change the connection structure of the deep neural network by introducing a residual module, to limit the prediction output to a reasonable range. Then, connect the Deep Residual Network (DRN) with a Generative Adversarial Network (GAN), which helps achieve data expansion during the training process to improve the accuracy of the assessment model.

Study results show that the proposed model achieves a better prediction effect on the dataset. The average performance and accuracy of the proposed model outperform the traditional models and the basic deep learning models tested in the paper.

The proposed model proved to be better performed naval propulsion system maintenance than the traditional models and the basic deep learning models. Therefore, our model may provide better maintenance advice for the naval propulsion system and will lead to a more reliable environment for offshore operations.

INSTALLED with naval type machinery, which includes steam and gas turbines geared to the same propeller shaft, H.M.S. Ashanti, built by Yarrow and Company, the first ship of the new Tribal class, has recently successfully completed its contractor's sea trials. The 7,500‐S.H.P. gas‐turbine provides a high concentration of compact power and is used to supplement the steam power for high‐speed work. Being able to develop its full power from cold within a few minutes, the gas turbine also provides exceptional mobility and enables the ship, lying in harbour without steam, immediately to got under way in case of emergency.

The purpose of this paper is to give an overview of the design issues of permanent magnet machines for the hybrid electric and plug‐in electric vehicles, including railway traction and naval propulsion.

Focus is given on both synchronous permanent magnet and reluctance machines. An overview of the design rules are provided, covering the topics of: fractional‐slot windings, fault‐tolerant configurations, flux‐weakening capability, and torque quality.

The peculiarities of these machines and the advanced design considerations to fit the automotive requirements are analyzed.

The paper includes a wide description of innovative electrical machines for electric vehicles, including not only the traction capability, but also analysis of features as weight reduction, torque ripple reduction, increase of fault tolerance, and so on.

The purpose of this paper is to describe the control and regulation of input DC voltages of nine‐level neutral point clamping (NPC) voltage source inverter (VSI).

The analysis and simulation of a cascade made up of three‐phase five‐level PWM rectifier‐nine levels NPC VSI are treated. This cascade is used to feed a permanent magnet synchronous machine (PMSM) drive. First, the five‐level PWM rectifier is presented. Then a topology of nine‐level NPC VSI and the associated PWM control strategy are described. In order to discard the problem of DC link voltage fluctuations, a clamping bridge with a PI regulation has been added to the cascade. Then a field‐oriented control strategy has been implemented in the PMSM.

The obtained results are full of promise to use the inverter in high voltage and great power applications such as electric naval propulsion systems.

The application of the proposed feedback control algorithm to the studied cascade offers the possibility of stabilizing the DC voltages. The studied cascade absorbs network currents with low‐harmonic content and unity power factor. In all, the instability problems associated with use of multilevel inverters are solved.

The purpose of this paper is to review maintenance practices, tools and parameters for marine mechanical systems that can be classified as plant, machinery and equipment (PME). It provides an insight for the maintenance crew on which maintenance parameters and practices are critical for a given PME systems.

The review paper characterizes the various maintenance parameters and maintenance practices used onshore and offshore for PME and identifies the possible gaps.

A variety of maintenance techniques are being used in the marine industry such as corrective maintenance, preventive maintenance and condition-based maintenance. As marine vehicles (MV) get older, the most important maintenance parameters become maintenance costs, reliability and safety. Maintenance models that have been developed in line with marine mechanical systems have been validated using a single system, whose outcome could be different if another PME system is used for validation.

There is a limited literature on MV maintenance parameters and maintenance characterization regarding mechanical systems. The maintenance practices or strategies of marine mechanical systems should be based on maintenance parameters that suit the marine industry for a given PME.

Based on the available literature, the paper provides a variety of maintenance framework, parameters and practices for marine mechanical systems. The paper further gives an insight on what maintenance parameters, strategies and platforms are given preference in the shipping industry.

The presented research is carried out in reaction to the soaring costs of fuel and tight control over environmental issues such as carbon dioxide emissions and noise. The purpose of this paper is to study the feasibility of applying the environmental-friendly energy source in an unmanned aerial vehicles (UAVs) propulsion system.

Currently, the majority of UAVs are still powered by conventional combustion engines. An electric propulsion system is most commonly found in civilian micro and mini UAVs. The UAV classification is reviewed in this study. This paper focuses mainly on application of electric propulsion systems in UAVs. Investigated hybrid energy systems consist of fuel cells, Li-ion batteries, super-capacitors and photovoltaic (PV) modules. Current applications of fuel cell systems in UAVs are also presented.

The conducted research shows that hybridization allows for better energy management and operation of every energy source onboard the UAV within its limits. The hybrid energy system design should be created to maximize system efficiency without compromising the performance of the aircraft.

The presented study highlights the reduction of the energy consumption, necessary to perform the mission and maximizing of the endurance with simultaneous decrease in emissions and noise level.

The conducted research studies the feasibility of implementing the environmental-friendly hybrid electric propulsion systems in UAVs that offers high efficiency, reliability, controllability, lack of thermal and noise signature, thus, providing quiet and clean drive with low vibration levels. This paper highlights the main challenges and current research on fuel cell in aviation and draws attention to fuel cell – electric system modeling, hybridization and energy management.

Cooldown of fuel inside a horizontal cylinder (i.d. approximately equal to that of a pylon tank) was modelled with a mixture of 50% glycerine and 50% water (Ti = 65°C). Safety considerations and poor optical qualities at low temperatures precluded fuel from being used in these experiments. The test was started by suddenly imposing a nominal 10°C external temperature field (flowing tap water) on the aluminium skin. Fluid velocities and temperatures were measured during the transient near the mid‐length plane of the cylinder, where end effects were reduced. Therefore, the physical situation at this plane was considered amenable to a 2‐D analysis. Tests were conducted with a full partially full tank and included tests with the tank tilted 10° from the horizontal to determine axial convection effects; this angle approximates an angle of attack during cruise. Tilting the tank produced temperatures at the elevated end which were significantly higher than those at the lowered end, especially for the bottom ½ of the tank where the ΔT between ends was as high as 5°C 30 minutes after the start of test.

PHOENICS, a general 3‐D Navier‐Stokes computer program, was used to simulate cooling and freezing of jet fuel stored in airplane fuel tanks. A 3‐D analysis is required for fuel tanks of arbitrary geometry exposed to time dependent and nonuniform boundary temperatures. The work reported in this paper concentrated on 2‐D simulations of fuel cooling and freezing in a wing tank and external (pylon) tanks as a step toward the 3‐D analysis. Significant progress has been made on obtaining plausible solutions over the entire range of conditions considered. The same model, with appropriate changes for fuel properties, could also be used to predict fuel heating in airplane fuel tanks during supersonic flight conditions.

The discipline of Human Factors is concerned to contribute to the Safety and Effectiveness of systems by the integration of scientific knowledge about human beings into total system design. The aim of this specialised two‐week course is to provide, for senior personnel in aviation, a review of human factors in relation to the design and operation of transport aircraft.

The background of missile costs is discussed. Missiles are new and very costly. Developments in this field have been subjected to political vicissitudes which have often upset long‐term developments. Missile technology is on the frontier of science and there is no background of knowledge to draw on; much basic and expensive research is required. Missile engineering models are complex in detail and assembly, and therefore costly, and constant change occurs while making and testing the model. The complexity and functional requirements of missile parts are running a parallel race with the machines and processes being developed to fabricate the materials required. The usually small runs required in missile production again add to costs. Imposed on all these activities is the requirement that reliability of near 100 per cent is needed and in no case can reliability be allowed to be secondary to cost. The inflight life and shelf conditions for a missile are usually fairly well established and 100 per cent reliability for a short operating life with a long shelf life are the real requirements. There is a considerable tendency to overdesign for reliability. Some costly features of design such as finest finish, closest tolerances and highest strength are carried over by habit from aircraft design and are not always required in missiles. Having examined some causes of high costs, a programme for cost reduction is set out. Costs can be reduced by: (i) earlier freezing of designs making changes only in groups of several changes at wider intervals, (ii) making a more realistic approach to reliability designs, (iii) selecting tolerances in a more analytical manner according to individual needs, (iv) selecting materials on the basis of actual design requirements instead of using the very best materials available even when the short life makes them unnecessary, (v) avoiding tool‐room methods in production engineering, (vi) setting work standards on as many operations as possible and enforcing them to the greatest degree possible, (vii) selecting the best type of workers to make the transition from development models to production missiles as smooth as possible, and (viii) setting up rigid systems and parts designation procedures for handling production parts. Finally, methods of organizing research and development and production for bridging the gap between engineering design and production are proposed.