Search Results (30)

Millimeter-wave-supported detonation (MSD) is a unique detonation phenomenon driven by a supersonically propagating ionization front, sustained by intense millimeter-wave beams. Microwave Rocket, which utilizes MSD to generate thrust from atmospheric air in a pulse detonation engine (PDE) cycle, is a promising low-cost alternative to conventional chemical propulsion systems for space transportation. However, insufficient air intake during repetitive PDE cycles has limited achievable thrust performance. To address this issue, a model equipped with a six-stage reed valve system (36 valves in total) was developed to ensure sufficient air intake, which measured 500 mm in length, 28 mm in radius, and 539 g in weight. Launch demonstration experiments were conducted using a 170 GHz, 550 kW gyrotron developed at the National Institutes for Quantum Science and Technology (QST). Continuous thrust was successfully generated by irradiating up to 50 pulses per experiment at each frequency between 75 and 150 Hz, in 25 Hz increments, corresponding duty cycles ranging from 0.09 to 0.18. A maximum thrust of 9.56 N and a momentum coupling coefficient $C_m$ of 116 N/MW were obtained. These values represent a fourfold increase compared to previous launch experiments without reed valves, thereby demonstrating the effectiveness of the reed valve configuration in enhancing thrust performance. Full article

Magnetic levitation (maglev) technology offers significant advantages for rail transport, including frictionless propulsion, reduced noise, and lower maintenance costs. However, its widespread adoption has been limited due to the need for a dedicated infrastructure incompatible with conventional rail networks. The MaDe4Rail project, funded by Europe’s Rail Joint Undertaking (ERJU), explores Maglev-Derived Systems (MDSs) as means to integrate maglev-inspired solutions into existing railway corridors with minimal modifications. This paper focuses on the so-called “hybrid MDS” configuration, which refers to levitating systems that can operate on existing rail infrastructure. Unlike current maglev systems, which require dedicated tracks, the proposed MDS system is designed to operate on conventional rail tracks, allowing for its compatibility with traditional trains and ensuring the interoperability of lines. In order to identify the most viable solution, two different configurations have been analysed. The evaluated scenario could benefit from the introduction of hybrid MDSs based on magnetic levitation, where a group of single vehicles, also called pods, is used in a virtual coupling configuration. The objective of this case study is to increase the capacity of traffic on the existing railway line by significantly reducing travel time, while maintaining a similar energy consumption to that of the current conventional trains operating on this line. Simulation results indicate that the hybrid MDS can optimise railway operations by taking advantage of virtual coupling to improve traffic flow, reducing travel times and energy consumption with the optimisation of the aerodynamic drag. The system achieves a balance between increased speed and energy efficiency, making it a viable alternative for future rail transport. An initial cost–benefit analysis suggests that the hybrid MDS could deliver substantial economic advantages, positioning it as a promising solution for enhancing European railway networks with minimal infrastructure investment. Full article

Electric and hybrid marine vessels are marking a new phase of eco-friendly maritime transport, combining electricity and traditional propulsion to boost efficiency and reduce emissions. The industry’s advancements in charging infrastructure and strict regulations help these vessels lead the way toward a sustainable and economically viable future in shipping. In this review, electric and hybrid marine vessels are discussed, including past applications and trend demonstrations. This paper systematically analyzes maritime vessels’ energy management and battery systems, highlighting advances in lithium-based and alternative battery technologies. Additionally, the review examines the impact of these technologies on sustainability and operational efficiency in the maritime industry. This paper contributes to the field by presenting a holistic view of the challenges and solutions associated with the electrification of maritime vessels, aiming to inform future developments and policymaking in this dynamic sector. Unlike many existing reviews that focus exclusively on battery chemistries or energy management algorithms, this manuscript integrates multiple aspects of maritime electrification—including propulsion types, charging infrastructure, grid systems (MVDC), EMS, BMS, and AI applications—into one cohesive systems-level review. This cross-sectional integration is particularly rare in the literature and enhances the practical value of the review for designers, policymakers, and shipbuilders. Full article

Inductive power transfer (IPT) systems are transforming railway infrastructure by enabling efficient, wireless energy transmission for electric locomotives equipped with Li-ion batteries. This technology eliminates the need for overhead power lines and third rails, offering financial and operational advantages over conventional electric propulsion systems. Despite its potential, IPT deployment in rail applications faces significant challenges, including the fragility of materials (i.e., ferrite and Litz wires), thermal management during high-power transfers, and electromagnetic interference (EMI) on the transmitter side. This study discusses several factors affecting IPT efficiency and introduces magnetic concrete as a durable and cost-effective material solution for IPT systems. Magnetic concrete combines soft ferrite powder with water and coarse aggregates to enhance magnetic functionality while maintaining structural strength comparable to conventional concrete. Its durability and optimized magnetic properties promote consistent power transfer efficiency, making it a viable alternative to traditional ferrite cores. A comparative study has been performed on non-magnetic and magnetic concrete (with 33% ferrite powder) using both permeability tests and finite element analysis (FEA). The FEA includes both thermal and electromagnetic simulations using Ansys Maxwell (v.16), revealing that magnetic concrete can improve temperature management and EMI mitigation, and the findings underscore its potential to revolutionize IPT technology by overcoming the limitations of traditional materials and enhancing durability, cost-efficiency, and power transfer efficiency. By addressing the challenges of fragility, thermal management, and shielding of the unique coil topology design presented, this study lays the groundwork for improving IPT infrastructure in sustainable and efficient rail transport systems. Full article

Motor vehicles in transport, as one of the important sectors of the economy, emit a significant amount of carbon dioxide and other products in the form of exhaust gases, which are harmful to human health. The emission of exhaust gases from motor vehicles is limited by appropriate regulations in accordance with environmental goals, such as the Paris Climate Agreement. Reduced emissions and fuel (energy) consumption is mainly achieved by applying modern technologies for the production of internal combustion engines; transitioning to cleaner fuels, such as renewable natural gas or biomethane; and using alternative propulsion systems. Biomethane stored in a liquid state in on-board reservoirs has advantages in truck transport, ships, and air traffic. The reason for this is due to the higher concentration of energy per unit volume of the reservoirs and the lower storage pressure and thus higher safety compared to the high-pressure storage option (compressed biomethane). The presented research is related to a proposition regarding the design of drive systems of city buses using biomethane as fuel in cases when fuel is stored on-board the vehicle as gas in a compressed aggregate state. In this study, the results of a calculation method regarding the roof-supporting structure of an experimental bus with gas reservoirs under higher pressure are discussed as well. This study also presents the possibility of reducing harmful emissions if biomethane is used instead of conventional fuels as a transitional solution to electric-powered vehicles. For the sake of comparison, it is suggested that the engaged energy and the amount of produced carbon dioxide emissions within the drive systems of different fuels are calculated according to the recommendations of the standard EN16258:2012. Full article

The aim of our study is to review the new vehicle diagnostic requirements that support economical and environmentally friendly operation. Vehicle technology is undergoing continuous and significant changes. At the same time, it is not enough to develop energy-efficient and environmentally friendly technologies; they must be operated in proper technical conditions and with proper driving techniques. Accordingly, new, innovative procedures are constantly needed for the economical and environmentally friendly operation of vehicles, and it is important to emphasize that vehicle diagnostics must also follow these changes! The practical applications of our publication and our research focus on several areas. This research is particularly important in the case of public transport vehicles and transport fleets. An important practical aspect is that large transport companies also achieve significant cost savings and, at the same time, contribute to environmentally friendly transport. The publication represents a new direction in vehicle diagnostics and research and development; this is the ECO-Diagnostics discussed in the material. ECO-Diagnostics is a procedure that takes into account both ecological and economic factors during vehicle diagnostic tests. Vehicle diagnostics, as an independent, professional, and scientific field, began to develop in the 1970s. This field of research experiences a paradigm shift, on average, every 20 years. Today, an epochal shift is taking place, with the development and spread of alternative propulsion systems (e.g., electric, hydrogen, or gas) and autonomous vehicles being the main areas of focus. The changes in vehicle technology must be followed by vehicle diagnostics too. Some of the already-known diagnostic methods (e.g., for internal combustion engines) can be included in this category, but new methods are also needed to enable the economical and environmentally friendly operation of vehicles. These facts make it important and urgent to define and research this area. Research in this area is particularly important for public transport vehicles and transport fleets. It is not enough to develop energy-efficient and environmentally friendly technologies: they must be operated in the right technical condition and with the right driving techniques for the intended purpose. This will help large transport companies to achieve significant cost savings and contribute to the environmentally friendly transport of passengers and goods. A major new area in vehicle diagnostics needs to be introduced and expanded. ECO-Diagnostics is a new category that has not been used before, and it also marks a new area of research and development. The article presents the basics of categorization and supports them with its own research results and application examples. As an introduction, a systematic overview of vehicle diagnostics as a whole is also provided. This is important (and novel) as no such systematic overview is available in the technical and scientific literature. The new category should also be included in this scheme. In parallel with the development of vehicles and diagnostic procedures, the methods and their context covered by the umbrella term ECO-Diagnostics (in ecological and economic terms) should, of course, be constantly expanded. Artificial intelligence can play an important role in this process. In the future, there will be a strong demand for the development of procedures in the field of ECO-Diagnostics. For both economic and environmental reasons, it is urgent and important to research and develop procedures in this category. This fact will also influence the work of researchers in the future. Full article

International regulations and market demand for zero-emission transportation are accelerating the adoption of sustainable solutions in the shipping industry. Wind-Assisted Propulsion Systems (WAPSs) present a promising alternative, as elaborated on in the EU-funded Orcelle Wind project. This paper deals with the integration of wing sails into the conceptual design of a Very Large Crude Carrier (VLCC) using a parametric, multi-objective optimization framework. The results reveal that optimized VLCC designs with WAPSs can achieve over 20% reductions in fuel consumption and greenhouse gas emissions compared to conventional designs. Additionally, the obtained optimized designs exhibit notable differences in the main design characteristics and hull form compared to conventional designs, highlighting the importance of multi-objective optimization in the early design stage to tap the potential of WAPS technologies and wind propulsion. Full article

Cruise ships function as a means of transport while simultaneously accommodating thousands of guests, providing a holiday experience with various entertainment options. This translates to high energy requirements for propulsion and hotel operations, typically covered by the combustion of fossil fuels. The operation of cruise vessels with fossil fuels contributes to carbon dioxide and also local harmful emissions in ports when shore power connections are not available. To enable cleaner and sustainable cruising, alternative technologies and fuels must be adopted. The present study evaluated the applicability of hydrogen fuel in combustion engines in a Meraviglia-class cruise ship. The fuel consumption of the ship was based on a real operation in Europe. This study examined how fuel energy in the form of LH₂ could be stored on the ship for a European cruise route and concludes that 3700 m³ of storage space would be needed to accommodate the liquid hydrogen. The mass of the LH₂ would only be one-third of that of fossil fuels, but the weight of the LH₂ tanks would most likely increase the total weight of the hydrogen storage. Additional new technologies and combined power production could significantly reduce the amount of LH₂ to be stored. Full article

Due to the reduction in diesel propulsion on railway networks across the world, it is essential to consider the introduction of an alternative propulsion where electrification would not be feasible. The introduction of alternative propulsions may influence the technological processes of train processing and interrupt its quantification methodology, due to their specific operational requirements. The problem of the quantification of technological processes of train processing is not sufficiently solved even in the field of conventional propulsions; therefore, the aim of this paper is to propose a unique methodological procedure for the quantification of selected processes of train processing operated by multiple units with a conventional or alternative propulsion. The new process quantification methodology enables the duration determination of a specific process, which can be simply determined for multiple units of different length and propulsion under local conditions. The duration determination is based on the final formula or its graphical representation. The function is based on data obtained by analysing the evaluated workflow of a model and multiple units using the PERT network analysis method. The proposed methodological procedure is verified by different types of propulsions through a case study using real values. The application of the methodology can prevent the risks related to non-compliance of the required technological times and at the same time increase the sustainability of the operation stability of railway passenger transport. Full article

We are currently seeing how new marine fuels are being introduced, such as Liquefied Natural Gas (LNG), Liquefied Petroleum Gas (LPG), hydrogen, ammonia, methanol, batteries, etc., for the propulsion of the world fleet with the aim of complying with the increasing IMO emissions regulations. The frenetic effort made by shipping companies to decarbonize maritime transport must be followed by an unstoppable adaptation of ports from the historical supply of only fuel and diesel to covering the demands of new fuels, ensuring their renewable origin; onshore power supply (OPS); or even the storage of captured CO₂. This article compiles the current environmental regulations applied to maritime transport to provide an analysis of the current situation and a link between vessels’ requirements to comply with such regulations and port environmental infrastructure. This work demonstrates that technological development is growing faster onboard vessels than at ports. It is demonstrated that except for the case of LNG, the theoretical shipping fuel world demand of each type of alternative fuel cannot be absorbed by current world production, where we found big gaps between supply and demand of up to 96.9%. This work concludes that to speed up this process, ports will need European aid as well as private investment. It is proposed that for the next steps, the port system needs to provide the required infrastructure to vessels on time, which inevitably means improvements in competitiveness and governance to promote the blue economy and the concept of smart ports, attracting main international shipping lines with a complete decarbonization hub on their routes by taking advantage of the geostrategic role of the Iberian ports. At the same time, the port governance model must be more flexible in the decision-making process, anticipating changes in maritime regulations with the challenge of coordinating public and private interests, serving as a link, once again, between ship and society. Full article

Recently, major climate events highlighted the increasing need to use sustainable technologies in the transportation domain. Energy production infrastructure, storage, and propulsion systems still rely on non-sustainable technology for economic growth. Therefore, this study reviews the modern transportation propulsion systems and transportation infrastructure components, describing the possible outcomes for several future directions based on prototypes and study advances. The in-production vehicles were reviewed for providing immediate, robust, and renewable solutions for the existing non-sustainable transportation infrastructure. The study continues with extended-capability vehicles and their limitations and vulnerability based on the current infrastructural circumstances. An alternative energy transfer infrastructure has been concluded to possibly provide the necessary capabilities to approach a neutral carbon footprint and mitigate ongoing climate adverse events. The hypothetical prototype uses distance energy transfer to bypass the described environmental constraints and provide a direction for achieving a possibly sustainable and economically evolving infrastructure. Full article

Given the increase in air traffic, the main challenges in aircraft design are in-flight emissions and noise heard by the community. These problems have thus far been solved by incremental improvements in aerodynamics, engine technology and operation. To dramatically reduce aviation’s carbon footprint towards an environmentally friendly air transport system, alternative propulsion concepts are one of the promising areas of research and first applications. In this context, the goal of integrating a hybrid-electric powertrain with a suitable airframe is to increase efficiency while reducing in-flight emissions, reduce noise for the community, drive down direct operating costs and increase reliability. This article presents an inexpensive approach to testing small, manned aircraft with a hybrid fuel–electric propulsion system. First, the design assumptions of the research flying platform are presented. Next, modifications of the existing two-seater glider are analyzed. These modifications are necessary to fit the fuel–electric hybrid propulsion system. The analysis allows us to select the elements of an appropriate hybrid electric system. It also shows that this type of small experimental propulsion system can be mounted on a two-seater aerobatic glider without significant structural modifications and still comply with the most important points of the Certification Standard-22. Finally, the design of the ground test stand for the propulsion system is described. It is believed that a thorough examination of the propulsion system on the ground will reveal both the advantages and disadvantages of the system. This should facilitate the successful installation of the system under study on a flying aircraft. Full article

The trend in the development of maritime and river propulsion systems is to make a transition from hydrocarbon to more environmentally friendly solutions. This contributes positively to the solution of the problems identified by the International Maritime Organization (IMO) regarding the high emissions of polluting gases emitted by maritime transportation. Currently, there is a wide variety of systems available due to the development of mobility technologies focused on decarbonization. This paper presents an analysis of technological alternatives for boats with electromobility applications and propulsion systems in the waterway field. First, a description of the operation of boats with electric motors, the different energy sources, and the alternative propulsion options is presented. Then, the electromobility technologies are characterized, analyzing the different configurations between the power source and the propulsion system. The results show a comparative table of technologies and their advantages and disadvantages. In addition, the most environmentally friendly technologies present significant challenges for large-scale implementation due to their recent development. In the short term, hybrid systems technologies present advantages over the others, as current systems are available, with the addition of equipment with higher efficiency and lower environmental impact. Full article

This article presents a review of cutting-edge technologies poised to shape the future of railway transportation systems, focusing on enhancing their intelligence, safety, and environmental sustainability. It illustrates key aspects of the energy-transport-information/communication system nexus as a framework for future railway systems development. Initially, we provide a review of the existing challenges within the realm of railway transportation. Subsequently, we delve into the realm of emerging propulsion technologies, which are pivotal for ensuring the sustainability of transportation. These include innovative solutions such as alternative fuel-based systems, hydrogen fuel cells, and energy storage technologies geared towards harnessing kinetic energy and facilitating power transfer. In the following section, we turn our attention to emerging information and telecommunication systems, including Long-Term Evolution (LTE) and fifth generation New Radio (5G NR) networks tailored for railway applications. Additionally, we delve into the integral role played by the Industrial Internet of Things (Industrial IoT) in this evolving landscape. Concluding our analysis, we examine the integration of information and communication technologies and remote sensor networks within the context of Industry 4.0. This leveraging of information pertaining to transportation infrastructure promises to bolster energy efficiency, safety, and resilience in the transportation ecosystem. Furthermore, we examine the significance of the smart grid in the realm of railway transport, along with the indispensable resources required to bring forth the vision of energy-smart railways. Full article

The current rapid technological change identifies the evolution of people’s transportation as one of the primary effects. Hybrid-electric propulsion reveals potential advantages, including fuel savings, lower pollution, and reduced noise emissions. It is becoming a viable alternative propulsion technology for ground and marine applications and the aviation sector. Hybrid-electric propulsion systems can meet the high demands of next-generation aircraft in terms of lower operating costs, economy, and fuel efficiency while maintaining high flight performance. Introducing similar disruptive technologies requires an evolution of the traditional certification approach and associated means of compliance. Even if it starts with evaluating a hybrid propulsion system, the proposed process can also be adopted in other areas where disruptive technologies need to be adopted, such as H2 fuel systems and active wings, to summarize some potential applications. The Certification Approach for Disruptive Technologies adopts a top–down process, reversing and mixing the usual certification approach currently used for aircraft. It is based on a safety assessment fully integrated into the system’s development. The result of this process will consist of a list of gaps in certification requirements, their classification based on gap solution impact, and proposals to close those gaps. Full article