Eng

Solar energy and biomass offer sustainable alternatives to meet the energy demand and reduce the environmental impact of fossil fuels. In this study, through mass and energy balances, a comparative analysis of energy, exergy, and environmental impact (LCA) was conducted on two renewable thermal sources: solar energy and coconut shell biomass, both coupled to a supercritical CO₂ Brayton cycle (sCO₂) with an organic Rankine cycle (ORC) for waste heat recovery. The sCO₂–ORC–biomass configuration showed higher exergy efficiency (41.1%) and lower exergy destruction (188.88 kW) compared to the sCO₂–ORC–solar system (23.76% and 422.63 kW). Thermal efficiency (50.6%) and net power output (131.73 kW) were similar for both sources. However, the solar system (204,055.57 kg CO₂-equi) had an 85.6% higher environmental impact than the biomass system (109,933.63 kg CO₂-equi). Additionally, the construction phase contributed ~95% of emissions in both systems, followed by decommissioning (~4.5%) and operation (~0.1%). Finally, systems built with aluminum generate a higher carbon footprint than those with copper, with differences of 2% and 3.2% in sCO₂–ORC–solar and sCO₂–ORC–biomass, respectively. This study and an economic analysis make these systems viable thermo-sustainable options for clean energy generation. Full article

A computational fluid dynamics study of the horizontal oil–water flow was performed using the Eulerian–Eulerian and mixture multiphase models in conjunction with the realizable k–ε turbulence model for the characterization of flow patterns. The experimental tests were carried out using water and mineral oil with a density of 880 kg/m³ and a viscosity of 180 cP, varying the superficial velocities of both fluids in ranges of 0.1–1.2 m/s and 0.1–0.5 m/s, respectively. The numerical model was defined under the same initial and boundary conditions as in the experiment. Moreover, the model is defined such that entering the fluids in a mixed state, the stratified pattern could form adequately with the two multiphase models. Although the Eulerian–Eulerian model, together with the geometric reconstruction scheme, allowed us to visualize the three-dimensional dispersed patterns in a very similar way to the experimental results, the mixture model did not exhibit such similarity, especially in the oil-in-water dispersions. Additionally, the Eulerian–Eulerian model was able to predict the experimental holdup values with an average error of 15.2%. Full article

The accurate counting of passengers in public transport systems is crucial for optimizing operations, improving service quality, and planning infrastructure. It can also contribute to reducing the number of public transport lines where a high number of vehicles is not needed in certain periods during the year, but also by increasing the number of lines where the need is increased. This paper provides a comprehensive review of current methodologies and technologies used for passenger counting, without the actual implementation of the automatic passenger counting system (APC), but with a proposal based on image processing and machine learning techniques and concepts, since it represents one of the most used approaches. The research explores various technologies and algorithms, like card swiping, infrared, weight and ultrasonic sensors, RFID, Wi-Fi, Bluetooth, LiDAR, thermos cameras, including CCTV cameras and traditional computer vision methods, and advanced deep learning approaches, highlighting their strengths and limitations. By analyzing recent advancements and case studies, this review aims to offer insights into the effectiveness, scalability, and practicality of different passenger counting solutions and offers a solution proposal. The research also analyzed the current General Data Protection Regulation (GDPR) that applies to the European Union and how it affects the use of systems like this. Future research directions and potential areas for technological innovation are also discussed to guide further developments in this field. Full article

Ponte de Vilanova, a masonry bridge, was built in Allariz, Galicia in the 13th–14th centuries. It is still standing. The structure, generally well preserved, shows minor deformations and wear signs caused by environmental factors. To conduct a comprehensive assessment without impacting the bridge’s integrity, drones equipped with thermal and underwater imaging technology were employed. Aerial inspections revealed vegetation growth and minor efflorescence (salt deposits) in some areas, while aerial thermography detected temperature variations along the stone joints, indicating the presence of moisture. The granite blocks comprising the bridge showed consistent quality and preservation. The underwater inspection confirmed that the bridge’s piers are well set on the riverbed, with no major damage observed, ruling out the immediate need for repair. This approach allowed a thorough evaluation of submerged parts without requiring divers, enhancing safety and reducing costs. Full article

This paper presents the development of an Artificial Intelligence (AI)-based integrated dynamic hybrid PV-H₂ energy system model together with a reflective comparative analysis of its performance versus that of the commercially available HOMER software. In this paper, a novel Particle Swarm Optimization (PSO) dynamic system model is developed by integrating a PSO algorithm with a precise dynamic hybrid PV-H₂ energy system model that is developed to accurately simulate the hybrid system by considering the dynamic behaviour of its individual system components. The developed novel model allows consideration of the dynamic behaviour of the hybrid PV-H₂ energy system while optimizing its sizing within grid-connected buildings to minimize the levelized cost of energy and maintain energy management across the hybrid system components and the grid in feeding the building load demands. The developed model was applied on a case-study grid-connected building to allow benchmarking of its results versus those from HOMER. Benchmarking showed that the developed model’s optimal sizing results as well as the corresponding levelized cost of energy closely match those from HOMER. In terms of energy management, the benchmarking results showed that the strategy implemented within the developed model allows maximization of the green energy supply to the building, thus aligning with the net-zero energy transition target, while the one implemented in HOMER is based on minimizing the levelized cost of energy regardless of the green energy supply to the building. Another privilege revealed by benchmarking is that the developed model allows a more realistic quantification of the hydrogen output from the electrolyser because it considers the dynamic behaviour of the electrolyser in response to the varying PV input, and also allows a more realistic quantification of the electricity output from the fuel cell because it considers the dynamic behaviour of the fuel cell in response to the varying hydrogen levels stored in the tank. Full article

A game problem of structural design is defined as a problem of playing against external circumstances. There are two classes of players, namely the “ordinal” and “cardinal” players. The ordinal players, designated as the “operator” and “nature”, endeavor to, respectively, minimize or maximize the payoff function, operating within the constraints of limited resources. The fundamental premise of this study is that the action of player “nature” is a priori unknown. Statistical decision theory addresses decision-making scenarios where these probabilities, whether or not they are known, must be considered. The solution to the substratum game is expressed as a value of the game “against nature”. The structural optimization extension of the game considers the value of the game “against nature” as the function of certain parameters. Thus, the value of the game is contingent upon the design parameters. The cardinal players, “designers”, choose the design parameters. There are two formulations of optimization. For the single cardinal player, the pursuit of the maximum and minimum values of the game reduces the problem of optimal design. In the second formulation, there are multiple cardinal players with conflicting objectives. Accordingly, the superstratum game emerges, which addresses the interests of the superstratum players. Finally, the optimal design problems for games with closed forms are presented. The game formulations could be applied for optimal design with uncertain loading, considering “nature” as the source of uncertainty. Full article

Neural networks (NNs) have revolutionized various fields, including aeronautics where it is applied in computational fluid dynamics, finite element analysis, load prediction, and structural optimization. Particularly in optimization, neural networks and deep neural networks are extensively employed to enhance the efficiency of genetic algorithms because, with this tool, it is possible to speed up the finite element analysis process, which will also speed up the optimization process. The main objective of this paper is to present how neural networks can help speed up the process of optimizing the geometries and composition of composite structures (dimension, topology, volume fractions, reinforcement architecture, matrix/reinforcement composition, etc.) compared to the traditional optimization methods. This article stands out by showcasing not only studies related to aeronautics but also those in the field of mechanics, emphasizing that the underlying principles are shared and applicable to both domains. The use of NNs as a surrogate model has been demonstrated to be a great tool for the optimization process; some studies have shown that the NNs are accurate in their predictions, with an MSE of $1\times {10}^{-5}$ and MAE of 0.007%. It has also been observed that its use helps to reduce optimization time, such as up to a speed 47.5 times faster than a full aeroelastic model. Full article

The demolishing of concrete structures such as bridges, tunnels, buildings, and pavements has become a common activity due to reasons such as renovation, rehabilitation, retrofitting, or simply ending the service life of these structures. This upsurge has brought major challenges in managing construction demolition waste (CDW). Traditional demolition techniques are often characterized by high environmental impacts, inefficiency in waste management, and safety concerns. This paper critically reviews traditional and emerging concrete structure demolition technologies in terms of efficiency, safety, environmental impact, waste minimization, and material recyclability. A detailed review of manual demolition, mechanical demolition, implosion, and relatively new techniques such as static blasting, diamond wire sawing, soundless chemical demolition agents, hydro demolition, electrical discharge technology, demolition robots, and microwave heating is conducted. The key findings of this paper are that various alternative technologies have significant advantages over their traditional counterparts by offering minimum environmental pollution, improvements in on-site safety, and a possibility for materials to be reused and recycled. For instance, hydro demolition and diamond wire sawing are very efficient and accurate, meaning that actual waste management is highly improved. This paper underlines that the choice of demolition methods adapted to project needs is crucial for the development of sustainable CDW management. Such findings are useful to practitioners and policymakers who have to make fully informed decisions to promote environmental sustainability and resource conservation goals. Full article

Smart technologies are increasingly used in agriculture, with drones becoming one of the key tools in agricultural production. This study aims to evaluate affordable drones for agricultural use in the Posavina region, located in northern Bosnia and Herzegovina. To determine which drones deliver the best results for small and medium-sized farms, ten criteria were used to evaluate eight drones. Through expert evaluation, relevant criteria were first established and then used to assess the drones. The selected drones are designed for crop monitoring and are priced under EUR 2000. Using the fuzzy A-SWARA (Adapted Step-wise Weight Assessment Ratio Analysis) method, it was determined that the most important criteria for drone selection are control precision, flight autonomy, and ease of use, all of which are technical attributes. The fuzzy MARCOS method revealed that the best-performing drones are also the most affordable. The drones D5, D4, and D8 demonstrated the best results. These findings were confirmed through comparative analysis and sensitivity analysis. Their features are not significantly different from those of more expensive models and can, therefore, be effectively used for smart agriculture. This study demonstrates that drones can be a valuable tool for small farms, helping to enhance agricultural practices and productivity. Full article

This study explores the feasibility of preparing a one-part alkali-activated binder produced from tungsten-molybdenum (W-Mo) tailings with sodium metasilicate (SM). A series of alkali-activated mortar samples were prepared, and the effects of the water/binder (W/B) ratio and mixture proportion on mechanical properties were investigated. Additionally, the microstructure and composition of the alkali-activated W-Mo tailings were characterized by using a combination of scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy techniques. Optimal results were achieved with a W/B ratio of 0.35 and a formulation containing 20% by weight of SM. Under these conditions, the cured samples exhibited an unconfined compressive strength of 11.2 MPa and a bulk density of 1726 kg/m³ after 28 days. The findings show the potential to advance tungsten-molybdenum mine waste upcycling and contribute to the production of environmentally sustainable building materials. Full article

A membrane unit for gas separation is not available in most process simulators, and therefore it needs to be built manually. However, the developed units are based on assumptions, and the system is solved numerically. The accuracy of these models with industrial data is rarely discussed in the literature, but it is needed to confirm the reliability of process simulators. In this work, the membrane unit was developed in two different simulation software such as the commercial UniSIM^® and the freeware CAPE-OPEN to CAPE-OPEN (COCO). In UniSIM^®, the membrane module was built internally using a component splitter, spreadsheet, and adjust functions. In COCO, the membrane unit was developed by program coding with the external computational software, Scilab. The developed membrane units were assessed with field data for fuel gas conditioning. Results show that the membrane unit was easier to build in UniSIM^® but when calculating the flowrate and composition of all compounds at the permeate and retentate sides, UniSIM^® gives an error of 17.4% while COCO gives a slightly lower error of 17.1%. The high error was related to the effects of plasticization and concentration polarization, which were not taken into consideration in the mathematical model. Full article

In this work, we develop a detailed analysis of the current outlook for electric vehicle charging technology, focusing on the various levels and types of charging protocols and connectors used. We propose a charging station for electric cars powered by solar photovoltaic energy, performing the analysis of the solar resource in the selected location, sizing the photovoltaic power plant to cover the demand completely, and exploring different configurations such as grid connection or physical and virtual electric energy storage. Despite the current development applying for specific working conditions, operating voltage, charging rate, power demand, etc., the proposed configuration is modular, adaptable, and resilient. The simulated system operates within the 360 V to 800 V range of direct current for charging the electric vehicles, with a selectable power range between 20 and 180 kW. The basic layout includes four charging poles, each servicing all working voltages. An oversized PV plant powers the charging station at any time of the year, saving money compared to the alternative of the electric storage unit. In addition, we build simulation tools and algorithms that optimize the design of future projects, providing a solid basis for sustainable energy infrastructure planning and design. Full article

This study aimed to quantify the postures and muscle activity while parks and gardens workers operated ride-on mowers during a typical shift. Eight participants operated ride-on mowers in the same park but on different terrains (flat and undulating). Body postures and muscle activity were collected wirelessly and unobtrusively. Participants adopted a forward-flexed seated posture with the predominant movement being head rotation. Oscillatory movements (20–40° from neutral) of the thorax in all three planes of movement were noted in all participants. Low levels (<30% MVIC) of muscle activity were recorded in all muscles tested. These levels were elicited for most (>90%) of the recording time. Higher (>50% MVIC) activation levels were interspersed through the data, but these were not sustained. There was no difference in posture or muscle activity between the flat and undulating terrain. The forward-flexed posture combined with vibration can increase the risk of discomfort and injury in the low back while ride-on mowing. The low levels of muscle activity suggest participants did not actively brace for the occupational situation and task. The large inter-participant difference in posture attests to subjective variation to accommodate muscular stress, and this may not be optimal for injury mitigation. Full article

Industrial architecture is the result of the integration of complex planning and construction, with the goal of attaining an optimal arrangement of building processes toward the creation of a quality working environment. The subject of research focuses on the architecture of light-industry buildings and product warehouses and includes sustainable smart concepts and laboratories for modern industry with high-quality production and working environments. All of this is expressed in the creation of architecture as a result of the meaningful dialogue among the components of architectural design. The goal of this research is to determine the main categories of the interaction of industrial architecture and construction and, at the same time, to provide an answer to the main research question of what the application determinates are in a given relationship: environment—architectural expression—construction. The quantitative and qualitative methods of research are focused on the choice, definition, and correlation (dialogue) of the elements of architecture and construction, in dependence on the character of the industrial activity. The research outputs, in the form of diagrams and illustrative graphic displays, make a contribution toward the visual interpretation of the architecture/construction relationship and the methodological basis for the creative process of designing industrial architecture within the context of contemporary trends. Their use in engineering and architecture education is of undoubted significance. Full article

Concrete production has increasingly used seawater to overcome the challenge of freshwater scarcity. Although the use of seawater in concrete still has a controversial reputation, it is a promising application, particularly when combined with mineral admixtures such as natural zeolitic tuffs (ZT). This paper aims to investigate the effect of using locally quarried ZT on the strength of unreinforced concrete mixed and/or cured using seawater. The mix proportions of the concrete were selected to obtain the optimum combination for the M20 grade of concrete with a water-to-cement ratio of 0.69. Moreover, 150mm-cubes and cylinders of 100 mm diameter by 200mm height were cast from the concrete mixtures, which contain 0%, 5%, 7.5%, 10%, and 25% of ZT as a partial replacement of silica sand. Splitting tensile tests and compressive strength tests were conducted on these specimens at 7, 28, and 90 days. The results show the harmful effect of seawater on the strength of plain concrete (without ZT) at 7, 28, and 90 days of curing, especially when seawater is used in both mixing and curing of the concrete. However, adding ZT in seawater-based concrete improved its strength apparently, especially at early curing ages. For example, using 10% of ZT as a partial replacement of silica sand increased the compressive strength of seawater based-concrete by 105.4%, 28.3%, and 34.6% after 7, 28, and 90 days of curing, compared with concrete without ZT and produced using seawater. These results contribute to the enhancement of the sustainability of both freshwater and concrete material through the use of ZT in producing concrete, particularly in areas where freshwater is scarce or expensive. Full article

The potential for energy efficiency in office buildings is critical, especially in regions facing rapid climate change impacts. This study investigates the use of phase change materials (PCMs) and double-skin façades (DSFs) to optimize energy performance in office buildings in Iran, a country with significant energy demands for heating and cooling. Utilizing Building Information Modeling (BIM) and EnergyPlus 24.1.0 software, we evaluated energy consumption trends across climate scenarios from 1981 to 2030. The findings underscore the rising energy demand due to global temperature increases and demonstrate that integrating PCMs and DSFs can mitigate energy consumption. This research highlights the importance of region-specific building strategies to achieve energy-efficient designs and contributes practical insights for developing sustainable energy policies in Iran. Full article

The decarbonization of industrial energy systems which comprise different networks (such as steam, water, electric power, fuel sources) is crucial for mitigating climate change and achieving sustainability goals. This paper presents a comprehensive methodology integrated in an open-source in-house tool for the coupled design and operation optimization of energy systems in industrial settings. The proposed approach integrates advanced optimization techniques with modeling of energy systems including properties like mass flow and temperature to simultaneously optimize both design parameters and operational strategies. The methodology encompasses the optimized integration of various energy technologies, such as renewable energy technologies, energy storage, and power-to-heat technologies while considering changing operational conditions and variable energy demand and supply. A multi-objective optimization framework is employed to balance conflicting targets, such as minimizing greenhouse gas emissions, operational costs, and ensuring system reliability. The in-house tool application considering a case study based on a food industry process demonstrates the effectiveness of the proposed approach in significantly reducing carbon footprints as well as operational and investment costs compared to traditional low-fidelity methods incorporated in commercial tools. The optimized concept achieved through the in-house tool has shown 8.5% less emission (EMI) compared to the optimized designs of the commercial tool. It shows 36% reduction in CO₂ emissions compared to the existing facility of the case study. The optimized energy concept can be implemented in the existing facility with a payback period of 4.6 years. The outcomes of the selected use-case highlight the importance of coordinated design and operation decisions in achieving optimal performance and sustainability in industrial energy systems. It also shows an ideal workflow for making optimized design decisions to decarbonize industry with novel energy concepts. Thus, this work provides a robust foundation for future research and practical applications aimed at accelerating the transition towards low-carbon industrial processes. Full article

Aluminium metal matrix composites (AMMCs) using alumina (Al₂O₃) and silicon carbide (SiC) as reinforcement elements are gaining significant interest in various applications because of their excellent properties. In this study, Al₂O₃/SiC with compositions (0.5 wt.%, 1.5 wt.%, and 2.5 wt.% for each) were used as reinforcement elements in an aluminium alloy (AA2024-T6). The samples prepared were AA2024-T6 + (0.5Al₂O₃/0.5SiC), AA2024-T6 + (1.5Al₂O₃/1.5SiC), and AA2024-T6 + (2.5Al₂O₃/2.5SiC) using a stir-casting technique. The experimental study included density calculation mechanical properties, such as tensile strength, compressive strength and hardness. The study also included a microstructure examination of the fracture surface of the tensile specimens. The results showed that incorporating Al₂O₃/SiC as reinforcement materials into aluminium AA2024-T6 significantly improved its properties. Hence, increasing the reinforcement with compositions of 2.5Al₂O₃/2.5SiC into AA2024-T6 showed a drop in density and increased mechanical properties, such as ultimate tensile strength, compressive strength and hardness, compared to the base alloy (AA2024-T6). Furthermore, the scanning electron microscopy analysis revealed the uniform distribution of the reinforcement particles resulting in strong bonding with the matrix. The findings suggest that Al₂O₃/SiC reinforced with AA2024-T6 can be used in applications where a combination of lightweight and high strength is needed. Full article

The coordinated operation of multiple jet devices enhances the efficiency of technological processes and thrust vector control systems, enabling the resolution of various practical challenges. Traditional jet control systems regulate the thrust vector in the direction from +20° to −20° in a 3D space. For the first time, this study considers, from a general perspective, the conditions under which the thrust vector angle can vary from +180° to −180° in any direction within a complete geometric sphere, including thrust reversal. Conceptual design using computational fluid dynamics (CFD) techniques considers kinematic schemes with variable lengths and flexible links. This study demonstrates the technical feasibility of controlled energy distribution through multidirectional ejector channels, including the maintenance of constant pressure at the nozzle apparatus inlet. Potential modernization strategies for the Laval nozzle incorporating a rotary diffuser were examined. The research outcomes are patented and aimed at developing a digital twin of the jet system for training artificial intelligence based on the philosophy of science and technology and Euler’s methodology within interdisciplinary works. The findings are primarily applicable to research and development efforts focused on creating energy-efficient oil and gas production systems. Furthermore, the research results can be applied to the development of advanced maneuverable unmanned vehicles and robotics for various purposes. Full article