Green synthesis of copper oxide (CuO) nanoparticles offers a sustainable alternative to conventional chemical methods that often involve toxic reagents and harsh conditions. This study investigates the use of Tithonia diversifolia, an invasive species in Sri Lanka, as a bioreductant for the eco-friendly fabrication of CuO nanoparticles. Using copper sulfate (CuSO₄·5H₂O) as a precursor, eight treatments were conducted by varying precursor concentration, temperature, and reaction time to determine optimal conditions. A visible color change in the reaction mixture initially indicated nanoparticle formation. Among all the conditions, treatment T4 (5 mM CuSO₄, 80 °C, 2 h) yielded the most favorable results in terms of stability, morphology, and crystallinity. UV-Vis spectroscopic analysis confirmed the synthesis, with absorbance peaks between 265 and 285 nm. FTIR analysis revealed organic functional groups and characteristic metal–oxygen vibrations in the fingerprint region (500–650 cm⁻¹), confirming formation. SEM imaging showed that particles were mainly spherical to polygonal, averaging 125–150 nm. However, dynamic light scattering showed larger diameters (~240 nm) due to surface capping agents. Zeta potential values ranged from −16.0 to −28.0 mV, indicating stability. XRD data revealed partial crystallinity with CuO-specific peaks. These findings support the potential of T. diversifolia in green nanoparticle synthesis, suggesting a low-cost, eco-conscious strategy for future applications.

Leading sugar-producing nations have been generating high volumes of sugarcane bagasse ash (SCBA) as a by-product. SCBA has the potential to be used as a partial replacement for ordinary Portland cement (OPC) in concrete, from thereby, mitigating several adverse environmental effects of cement while keeping the cost of concrete low. The majority of the microstructure of SCBA is composed of SiO₂, Al₂O₃, and Fe₂O₃ compounds, which can provide pozzolanic properties to SCBA. In this paper, literature on the enhancement of the mechanical properties of SCBA-incorporating concrete is analyzed. Corresponding process parameters of the SCBA production process and properties of SCBA are compared in order to identify relationships between the entities. Furthermore, methods, including sieving, post-heating, and grinding, can be used to improve pozzolanic properties of SCBA, through which the ideal SCBA material parameters for concrete can be identified. Evidence in the literature on the carbon footprint of the cement industry is utilized to discuss the possibility of reducing CO₂ emissions by using SCBA, which could pave the way to a more sustainable approach in the construction industry. A review of the available research conducted on concrete with several partial replacement percentages of SCBA for OPC is discussed.

Nanofluids, fluids with different suspended nanoparticles, have shown improved thermo-physical properties in recent research outputs, and they have emerged as promising alternatives for the industrial fluids used in numerous heat exchange applications. Much research has been conducted around the world to develop heat transfer fluids with optimum thermo-physical properties with the help of nanotechnology, especially in the 21st century. Following the latest research outcomes, nanofluids with base fluids of industrially used coolants, such as water, engine oil, transformer oil, electronic coolants, etc., have shown imposing thermo-physical properties compared to their base fluid. Identifying the nanofluids with high performances and lesser practical obstacles to be used as heat transfer fluids is vital. This paper reviews the thermo-physical property improvements of nanofluid properties, such as thermal conductivity, viscosity, density, specific heat capacity, and flash point, along with their theoretical models. Recent studies on using surfactants to improve the stability of nanofluids are also included in this review. The next part of the study reviews the latest research outputs on the thermo-physical properties of nanofluids in applications in engineering disciplines. Later, research on molecular dynamics simulations of nanofluids are discussed. As the final section, this paper presents Nanofluid research related to neural network modeling. Cumulatively, this paper presents a comprehensive review of recent nanofluids research, along with theoretical developments. This review is a cumulative study of the recent studies of nanofluid research in different disciplines. Most of the recent reviews focused on specific applications of nanofluids and do not cover the field from the basics of the nanofluids to their applications. However, this review covers all the aspects of the nanofluid field, along with several important engineering applications.

Water ingression is a critical issue in honeycomb composite structures, which could result in catastrophic structural failure. In the aviation industry, they are widely used to manufacture critical aircraft structural components including fuselage, wings, and flight control surfaces. Catastrophic failure of these structures would be disastrous, thus identifying water accumulation in earlier stages of the defect is necessary. The conventional non-destructive testing method is thermography which is performed using handheld thermography cameras by manually accessing the specific areas. This method of inspection has been identified to be a risky, costly, time-consuming, and inspector-dependent technique. This paper describes using a wall-climbing robotic platform that can be controlled remotely to access and perform the inspection on a targeted structural area replacing the manual process. The designed wall-climbing inspection robot onboard a heat pump to stimulate the composite surface to an adequate temperature and, an infrared sensor to feed the real-time temperature data via Bluetooth serial communication to a remote computer system to be processed into a thermal image and evaluated to determine the presence of water. The results obtained from the thermographic sensor are validated with the comparison of the Fluke thermography camera.

The poor thermal and physical properties of conventional engine oils limit vehicle performance and durability. This research aims to investigate the effect of nanoparticles such as fullerene C₆₀, titanium dioxide (TiO₂), iron oxide (Fe₂O₃), and reduced graphene oxide (rGO) nanoparticles on 10W30 Mobil engine oil. In this study, the effect of nanoparticle concentrations at different mass fractions (0.01, 0.05, and 0.1) was examined within the temperature range 30–120 °C. The nanofluids were prepared using a two-step direct mixing method and thermal properties were measured using a LAMBDA thermal conductivity meter, which uses the transient hot wire method according to the ISO standards. Due to the low concentrations of the nanofluids, surfactants were not required at all, and the stability of the nanofluids was visually monitored over a period of four weeks. Accordingly, the largest improvement in thermal conductivity occurred with TiO₂/10W30 at a mass fraction of 0.1 wt.% at 80 °C, and the specific heat capacity improved due to Fe₂O₃/10W30 addition at a mass fraction of 0.1 at 70 °C; these were 5.8% and 14.4%, respectively, for the base oil. Thermal diffusivity remained largely unaffected by the addition of the nanoparticles, and fullerene C₆₀ showed no significant effect on any thermal property. It was concluded that the thermal properties of the engine oil were considerably enhanced by the added nanoparticles at different weight fractions and temperature values.

Generally, paper-pulp-based materials are emerging in the packaging industry due to their high degree of biodegradability. Along with agricultural byproducts as an alternative, using additive or secondary materials in various processes and products has been a solution for implementing sustainability in material utilization. However, biodegradable materials still need to be improved due to the lack of properties which are essential for their use as packaging material. Currently, a number of research attempts have focused on enhancing the mechanical and thermal properties to increase the effectivity of those biodegradable materials for use as packaging material. The objective of this study is to analyze the effectivity of using sugarcane bagasse ash (SCBA) and wheat flour (starch) as a strengthening and thermal resistive additive. Due to its proven nano range particle size and fibrous nature, this material could positively affect the material properties. A total of twelve samples were prepared by varying the weight fraction of SCBA, white flour, and paper pulp. A compression molding method was used to prepare cylindrical samples with a diameter of 50 mm and a height of 55 mm under a compression load of 2 tonnes. Wet molded cylindrical blocks were oven-dried at 105 °C for 48 h to remove excessive moisture from the samples. Subsequently, all the samples were dried further until no significant weight loss was observed after the drying process to ensure their uniform moisture conditions. The prepared samples were tested for compressive strength using a Universal Testing Machine (UTM). Both load and compressive stress acting on each sample were plotted against the deflection of the sample. For the analysis, the deflection of each sample was measured at 8.6 kN load and the sample with 10% SCBA and 12.5% starch exhibited the least displacement among all additives. The results show that the samples with 10% SCBA and 12.5% starch also had the highest compressive strength compared to the other samples. Further, samples with the same amount of SCBA were analyzed for thermal resistivity and to obtain the thermal behavior of samples which is crucial in food packaging.Overall, most of the SCBA and starch mixed samples showed superior compressive strength compared to the pure paper-pulp-based sample.