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This paper aims to experimentally evaluate the performance of a parallel hybrid propulsion system for use in small unmanned aerial vehicles (UAVs).

The objective is to combine all the individual components of the hybrid electric propulsion system (HEPS) into a modular test bench to characterize the performance of a parallel hybrid propulsion system, and to evaluate a rule-based controller based on the ideal operating line concept for the control of the power plant. Electric motor (EM) designed to supplement the power of the internal combustion engine (ICE) to reduce the overall fuel consumption, with the supervisory controller optimizing ICE torque.

The EM was able to supplement the power of the ICE to reduce fuel consumption, and proved the capability of acting as a generator to recharge the batteries drawing from ICE power. Furthermore, the controller showed that it is possible to reduce the fuel consumption with a HEPS when compared to its gasoline counterpart by running simulated representative UAV missions. The findings also highlighted the challenges to build and integrate the HEPS in small UAVs.

The modularity of the test bench allows each component to be changed to assess its impact on the performance of the system. This allows for further exploration and improvements of the HEPS in a controlled environment.

This paper aims to investigate a multi-objective electric vehicle’s (EV’s) synergetic scheduling problem in the automotive industry, where a synergetic delivery mechanism to coordinate multiple EVs is proposed to fulfill part feeding tasks.

A chaotic reference-guided multi-objective evolutionary algorithm based on self-adaptive local search (CRMSL) is constructed to deal with the problem. The proposed CRMSL benefits from the combination of reference vectors guided evolutionary algorithm (RVEA) and chaotic search. A novel directional rank sorting procedure and a self-adaptive energy-efficient local search strategy are then incorporated into the framework of the CRMSL to obtain satisfactory computational performance.

The involvement of the chaotic search and self-adaptive energy-efficient local search strategy contributes to obtaining a stronger global and local search capability. The computational results demonstrate that the CRMSL achieves better performance than the other two well-known benchmark algorithms in terms of four performance metrics, which is inspiring for future researches on energy-efficient co-scheduling topics in manufacturing industries.

This research fully considers the cooperation and coordination of handling devices to reduce energy consumption, and an improved multi-objective evolutionary algorithm is creatively applied to solve the proposed engineering problem.

This paper aims to conduct a comprehensive literature review in the tidal energy physics, the ocean environment, hydrodynamics of horizontal axis tidal turbines and bio-mimicry.

The paper provides an insight of the tidal turbine blade design and need for renewable energy sources to generate electricity through clean energy sources and less CO₂ emission. The ocean environment, along with hydrodynamic design principles of a horizontal axis tidal turbine blade, is described, including theoretical maximum efficiency, blade element momentum theory and non-dimensional forces acting on tidal turbine blades.

This review gives an overview of fish locomotion identifying the attributes of the swimming like lift-based thrust propulsion, the locomotion driving factors: dorsal fins, caudal fins in propulsion, which enable the fish to be efficient even at low tidal velocities.

Finally, after understanding the phenomenon of caudal fin propulsion and its relationship with tidal turbine blade hydrodynamics, this review focuses on the implications of bio-mimicking a curved caudal fin to design an efficient horizontal axis tidal turbine.

This paper deals with the estimation of the necessary masses of propulsion components for multirotor UAS. Originally, within the design process of multirotors, this is an iterative problem, as the propulsion masses contribute to the total takeoff mass. Hence, they influence themselves and cannot be directly calculated. The paper aims to estimate the needed propulsion masses with respect to the requested thrust because of payload, airframe weight and drag forces and with respect to the requested flight time.

Analogue to the well-established design synthesis of airplanes, statistical data of existing electrical motors, propellers and rechargeable batteries are evaluated and analyzed. Applying Rankine and Froude’s momentum theory and a generic model for electro motor efficiency factors on the statistical performance data provides correlations between requested performance and, therefore, needed propulsion masses. These correlations are evaluated and analyzed in the scope of buoyant-vertical-thrusted hybrid UAS.

This paper provides a generic mathematical propulsion model. For given payloads, airframe structure weights and a requested flight time, appropriate motor, propeller and battery masses can be modelled that will provide appropriate thrust to lift payload, airframe and the propulsion unit itself over a requested flight time.

The model takes into account a number of motors of four and is valid for the category of nano and small UAS.

The presented propulsion model enables a full numerical design process for vertical thrusted UAS. Hence, it is the precondition for design optimization and more efficient UAS.

The propulsion model is unique and it is valid for pure multirotor as well as for hybrid UAS too.

This paper aims to suggest a new thermonuclear space propulsion and electric generator for aerospace.

Methods of thermonuclear physics are used for research.

The paper applies, develops and researches mini‐sized Micro‐AB thermonuclear reactors for space propulsion and space power systems. These small engines directly convert the high‐speed charged particles produced in the thermonuclear reactor into vehicle thrust or vehicle electricity with maximum efficiency. The simplest AB‐thermonuclear propulsion offered allows spaceships to reach speeds of 20,000‐50,000 km/s (1/6 of light speed) for fuel ratio 0.1 and produces a huge amount of useful electric energy. The offered propulsion system permits flight to any planet of the solar system in a short time and to the nearest non‐Sun stars by E‐being or intellectual robots during a single human life period.

Technical limitations may be apparent.

The theory of this propulsion and electric generator is developed and possibilities researched.

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.

When comparing and contrasting different types of fixed-wing military aircraft on the basis of an energetic efficiency figure-of-merit, unmanned aerial vehicles (UAVs) dedicated to tactical medium-altitude long-endurance (MALE) operations appear to have significant potential when hybrid-electric propulsion and power systems (HEPPS) are implemented. Beginning with a baseline Eulair drone, this paper aims to examine the feasibility of retro-fitting with an Autarkic-Parallel-HEPPS architecture to enhance performance of the original single diesel engine.

In view of the low gravimetric specific energy performance attributes of batteries in the foreseeable future, the best approach was found to be one in which the Parallel-HEPPS architecture has the thermal engine augmented by an organic rankine cycle (ORC). For this study, with the outer mould lines fixed, the goal was to increase endurance without increasing the Eulair drone maximum take-off weight beyond an upper limit of +10%. The intent was to also retain take-off distance and climb performance or, where possible, improve upon these aspects. Therefore, as the focus of the work was on power scheduling, two primary control variables were identified as degree-of-hybridisation for useful power and cut-off altitude during the en route climb phase. Quasi-static methods were used for technical sub-space modelling, and these modules were linked into a constrained optimisation algorithm.

Results showed that an Autarkic-Parallel-HEPPS architecture comprising an ORC thermal energy recovery apparatus and high-end year-2020 battery, the endurance of the considered aircraft could be increased by 11%, i.e. a total of around 28 h, including de-icing system, in-flight recharge and emergency aircraft recovery capabilities. The same aircraft with the de-icing functionality removed resulted in a 20% increase in maximum endurance to 30 h.

Although the adoption of Series/Parallel-HEPPS only solutions do tend to generate questionable improvements in UAV operational performance, combinations of HEPPS with energy recovery machines that use, for example, an ORC, were found to have merit. Furthermore, such architectural solutions could also offer opportunity to facilitate additional functions like de-icing and emergency aircraft recovery during engine failure, which is either not available for UAVs today or prove to be prohibitive in terms of operational performance attributes when implemented using a conventional PPS approach.

This technical paper highlights a new degree of freedom in terms of power scheduling during climbing transversal flight operations. A control parameter of cut-off altitude for all types of HEPPS-based aircraft should be introduced into the technical decision-making/optimisation/analysis scheme and is seen to be a fundamental aspect when conducting trade-studies with respect to degree-of-hybridisation for useful power.

The purpose of this paper is to demonstrate how opting for multiple contributors to the lowC economy and introducing new intelligent solutions allows a smooth transition to renewable fuels. Undoubtedly, biofuels are no longer everybody's darling. This is partly owed to the need to produce bio fuels at the lowest possible price and absent sustainability regulations or their enforcement like the European parliament initiated by banning bio fuels with not sufficient evidence of saving CO₂. But on the other hand, the end of cheap oil is clearly visible and it is clear that second generation lowC fuels may by no means be able to replace all of the worlds growing fuel consumption in a few years.

The paper presents a tri‐fold approach which has originated of two EU‐projects (SUGRE and RECODRIVE) based on reduction of the propulsion demand, intelligent powertrain configuration and the use of residues and waste as feedstock. The RECODRIVE approach tested in the European project with the same name introduces a quality management in fleet management which comprises procurement, driving and maintenance. This approach comprising also logistics should be able to reduce the propulsion demand at least by 10 per cent targeting 30 per cent and more.

Hybrid power trains are regenerating the braking energy and are reducing the propulsion demand by 15‐25 per cent in stop'n go traffic in cities. Parallel or power split hybrids may operate with phlegmatized and thus more efficient combustion engines, but serial hybrid electric power trains drive this characteristics, the extreme which is helpful introducing alternative fuels. They decouple the production of energy from the throttle command and allow for a more steady operation of the internal combustion engine.

By employing a serial hybrid power train simpler low‐RPM engines may be used which are modified to run on plant oils and other alternative fuels which are difficult to use in modern highly performing diesel engines. By reducing the propulsion demand, a higher share of alternative fuels based on natural feedstock may be achieved. This feedstock may be also amended by better utilising waste. The paper describes two examples. In Graz, used frying oil is collected to feed a transesterification plant and in Linköping waste from the meat industry is collected to produce biogas.

The approach enables the transport sector to increase the independence on oil at short‐term without the risk of putting a lot of venture capital in the wrong fuel or engine technology. The serial hybrid electric concept remains the basis for future solutions working on different end energy like hydrogen.

THE effect of the propulsive efficiency is analysed for all speed regions and methods for obtaining optimum propulsive efficiency for any speed and environmental conditions are investigated for different type vehicles. Also, the importance of the propulsive efficiency is compared to other factors such as weight of power plant, specific fuel consumption, specific power ratio, specific thrust ratio, etc. Finally, on the basis of considering all power plant factors, it is shown how to achieve optimum propulsion for any vehicle at required operating conditions.

The paper seeks to propose and analyze a new electrostatic ramjet space engine.

The upper atmosphere (85‐1,000 km) is extremely dense in ions (millions per cubic cm). The interplanetary medium contains positive protons from the solar wind. A charged ball collects the ions (protons) from the surrounding area and a special electric engine accelerates the ions to achieve thrust or decelerates the ions to achieve drag. The thrust may have a magnitude of several Newtons. If the ions are decelerated, the engine produces a drag and generates electrical energy. The theory of the new engine is developed.

It is shown that the proposed engine driven by a solar battery (or other energy source) cannot only support satellites in their orbit for a very long time but can also work as a launcher of space apparatus. The latter capability includes launch to high orbit, to the Moon, to far space, or to the Earth's atmosphere (as a return thruster for space apparatus or as a killer of space debris). The proposed ramjet is very useful in interplanetary trips to far planets because it can simultaneously produce thrust or drag and large electric energy using the solar wind.

Two scenarios, launch into the upper Earth atmosphere and an interplanetary trip, are simulated and the results illustrate the excellent possibilities of the new concept.