Unsustainable fossil fuels are mainly used to generate power in compression ignition (CI) engines in industry now. Due to fossil fuel depletion and potential environmental hazards, it is necessary for researchers to find alternative energy resources to adequately substitute hydrocarbon fossil fuels in current engines. A huge number of studies have focused on the use of renewable fuels in CI engines along with conventional petroleum fuels. Therefore, this paper aimed to analyze the effect of gaseous fuels added to CI engines as a supplement, such as H₂, biogas and syngas, in dual fuel mode with diesel as an alternative fuel. This paper analyzed several important characteristics, on which engine evaluation of CI engines using gaseous fuel as an additive is based, such as combustion, performance and emissions, and compared them with those of CI engines operating in single-fuel mode. The findings of numerous empirical studies are shown in graphs of particular parameters, which were crucial for investigating and assessing the case. The main conclusions indicated that gaseous fuel enrichment caused slight decline of performance in CI dual-fuel engine but actually improved emissions. In addition, this paper thoroughly analyzed various methods to assess the performance of biogas in CI dual-fuel engines and investigated dangerous emission pollution.

Thermal Energy Storage (TES) system has emerged as a promising solution of energy demand and supply management, which stores excess thermal energy and releases it when energy demand is high, making it an efficient and cost-effective energy storage solution when combined with renewable energy sources, such as solar and wind power. This study aimed to evaluate the thermal performance of TES units using Computational Fluid Dynamics (CFD) simulations in the ANSYS CFX software package. After comparing the heat storage capacity of conventional Phase Change Material (PCM) and iron oxide/paraffin wax composite (2%) using industrial residual water, temperature distribution plots and heat flux data were generated in simulations for both cases. Addition of iron oxide nanoparticles significantly improved the heat absorption performance of TES units. Both materials initially exhibited a higher heat absorption rate, which gradually decreased over time. CFD data analysis revealed that iron oxide/paraffin wax material enhanced heat absorption performance by up to 1.3%, which demonstrated the potential of iron oxide nanoparticles in improving the efficiency of TES system and highlighted the advantages of TES system combined with renewable energy sources. By improving heat absorption properties, the incorporation of iron oxide nanoparticles had the potential to increase the lifespan of TES units and significantly reduced maintenance and replacement expenses. This breakthrough, along with the cost savings and energy efficiency offered by TES technology, may encourage its widespread application, thus reducing reliance on fossil fuels and promoting sustainable energy practices.

This paper aimed to analyze the properties of rubber agglomerate panel, a heterogeneous material. After making three adjustments using three classical differential fractional models, namely, the Scott-Blair model, the generalized fractional Maxwell model (FMM), and the 1D standard fractional viscoelastic order for fluids (SFVOF), this paper assessed the number of parameters in those models for rubber agglomerate panel, made from rubber grains and urea thermoplastic elastomer (TPE). Combining data published from an undergraduate thesis with Microsoft Excel software and the solver command, this paper obtained better sample results using four parameters, rather than two or three complicated material function equations. Data of Ribeiro Alves in 2019 came from hardness experiments. Then this paper transformed deformation data into creep compliance in accordance with equation $J(t)=\varepsilon / t$ (mm/s), and obtained graphical adjustment representations, parameter values, and eventually adjustment equations. However, results from the modified FMM and 1D SFVOF were more comparable, and certain hypotheses were investigated to choose the better model. It was determined that the generalized FMM fit the data the best for this time period. With a certain margin of error, this model could be used for constructing new recycled materials and rubber agglomerate panel using Salvadori equipment. However, it is suggested that new and recent materials should be tested in order to solve environmental problems.

This study examines the energy and exergy performance of the Khoy dual fuel combined cycle power plant, focusing on dual pressure heat recovery steam generators (HRSGs). The aim is to identify an optimal design through the development of a thermodynamic model using ASPEN PLUS software. In the simulation, isentropic efficiencies of high-pressure and low-pressure steam turbines, gas turbines, and compressors are assumed to be 0.85, 0.80, 0.85, and 0.85, respectively. Various practical parameters, such as compressor pressure, condenser pressure, high-pressure steam turbine pressure, and outlet and inlet temperatures of superheaters and turbines, are investigated for their effects on energy and exergy efficiencies. The analysis reveals that combustion chamber I and combustion chamber II contribute the highest amounts of exergy destruction, accounting for 21.80% and 21.50% of the total exergy destruction, respectively. These areas are identified as requiring improvement. Based on the findings, an optimal design is presented, resulting in significant enhancements in energy and exergy efficiencies. The energy efficiency experiences a remarkable increase of 8.75%, while the exergy efficiency demonstrates a substantial improvement of 22.04%. This underscores the superiority of the optimized power plant configuration and provides valuable insights for designers, engineers, and power plant operators. In conclusion, this study advances the understanding of the energy and exergy performance of the Khoy dual fuel combined cycle power plant and offers guidance for optimizing its design and operation.

The development of an effective cooling system is paramount for the optimal design of high altitude Unmanned Aerial Vehicles (UAVs). These vehicles often operate at or near supersonic speeds in thin atmospheric conditions to generate sufficient lift. It is emphasized that the necessity for air-cooling mandates the incorporation of cooling ducts into the initial design, striving for a balance between low-speed, high-density cooling air for efficient heat rejection, minimal drag, or even potential thrust augmentation. The proposition is that dedicated, meticulously optimized cooling air pathways may facilitate superior performance at high altitudes. The abstract further underscores that the longevity and efficiency of solar panels, commonplace in solar-powered UAVs, are substantially temperature-dependent. As such, high-altitude cooling poses a complex challenge. For conventionally fueled jet-powered UAVs, fuel may serve as a viable heat sink, necessitating a design approach that integrates Peltier cells within electronic components. An alternative approach involves the installation of a subsonic Meredith duct within the primary air intake of the main turbo engine. This duct operates by reducing air speed at the face of a high-efficiency air-to-liquid radiator and then expanding the heated air into a nozzle, making the application of radiators feasible, even for supersonic UAVs. The feasibility of deploying the Meredith duct with direct exposure to external air in subsonic UAVs is also explored. This investigation thus sheds light on innovative cooling mechanisms for UAVs operating at high altitudes, potentially leading to improved efficiency and lifespan of critical components. The findings are poised to enhance the understanding of UAV design and operation, contributing to their overall performance and effectiveness.