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.

The field of bio-nanotechnology has seen significant advancements in recent years, particularly in the synthesis and application of bio-nanoparticles (BNPs). This review focuses on the green synthesis of BNPs using biological entities such as plants, bacteria, fungi, and algae. The utilization of these organisms for nanoparticle synthesis offers an eco-friendly and sustainable alternative to conventional chemical and physical methods, which often involve toxic reagents and high energy consumption. Phytochemicals present in plant extracts, unique metabolic pathways, and biomolecules in bacteria and fungi, and the rich biochemical composition of algae facilitate the production of nanoparticles with diverse shapes and sizes. This review further explores the wide-ranging applications of BNPs in various fields like therapeutics, fuel cells, energy generation, and wastewater treatment. In therapeutics, BNPs have shown efficacy in antimicrobial, anti-inflammatory, antioxidant, and anticancer activities. In the energy sector, BNPs are being integrated into fuel cells and other energy generation systems like bio-diesel to improve efficiency and sustainability. Their catalytic properties and large surface area enhance the performance of these devices. Wastewater treatment is another critical area where BNPs are employed for the removal of heavy metals, organic pollutants, and microbial contaminants, offering a cost-effective and environmentally friendly solution to water purification. This comprehensive review highlights the potential of bio-nanoparticles synthesized through green methods. It highlights the need for further research to optimize synthesis processes, understand mechanisms of action, and expand the scope of their applications. BNPs can be utilized to address advantages and some of the pressing challenges in medicine, energy, and environmental sustainability, paving the way for innovative and sustainable technological advancements in future prospects.

The efficiency, durability, and overall performance of a car engine are influenced by several critical factors. The quality and properties of engine oil play a crucial role, and oil is used in internal combustion engines for lubrication and cooling purposes. This research study aimed to compare the impact of fullerene-C₆₀ (99.5%), Fe₂O₃, and TiO₂ nanoparticles on the thermal properties of C.A.L.T.E.X. red engine oil with grades 10W30, 20W40, and 20W50. This study focused on the effect of a nanoparticle concentration of 0.01 wt.% in different engine oil grades at various temperature values of 30–120 °C. The nanofluids were prepared using the two-step direct mixing method, employing a magnetic stirrer and an ultrasonicator, ensuring uniform distribution of nanoparticles in the base fluids. The thermal conductivity, thermal diffusivity, and volumetric heat capacity of the base fluids and nanofluids were measured using the FLUCON LAMBDA thermal conductivity meter. Additionally, flash points were measured using the flash point tester. It was concluded that the thermal properties of TiO₂ and Fe₂O₃ showed considerable enhancement; in contrast, fullerene only showed a 212 °C flash point.

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.

Motion Capture (MoCap) has become an integral tool in fields such as sports, medicine, and the entertainment industry. The cost of deploying high-end equipment and the lack of expertise and knowledge limit the usage of MoCap from its full potential, especially at beginner and intermediate levels of sports coaching. The challenges faced while developing affordable MoCap systems for such levels have been discussed in order to initiate an easily accessible system with minimal resources.

This study investigates the impact of incorporating TiO₂ nanoparticles into two types of oils at different temperatures and with varying volume fractions: transformer oil (NYTRO LIBRA) and virgin coconut oil (manufactured by Govi Aruna Pvt. Ltd., Gampaha, Sri Lanka). The nanofluids were prepared using a two-step method by adding CTAB (cetyltrimethylammonium bromide) surfactant. To minimize nanoparticle agglomeration, this study employed relatively low-volume fractions. Thermal properties by means of thermal conductivity, thermal diffusivity, and volumetric heat capacity were measured in accordance with ASTM (American Society for Testing and Materials) standard methods using a multifunctional thermal conductivity meter (LAMBDA thermal conductivity meter). The measured thermal conductivity values were compared with theoretical models and previous research findings. It was confirmed that the modification of thermal properties was enhanced by doping TiO₂ nanoparticles with different volume fractions.