Al2O3 Nanoparticles Research Articles

Modelling to predict performance and emission parameters of hydrogen, additive and nano-particles blended fuel in a dual-fuel diesel engine through artificial neural network

The depleted state of fossil fuels has led to the need to find an alternate solution for the utilization of transportation vehicles. The use of hydrogen, fuel additives, and nanoparticles has been part of the research in the recent past. Additionally, the use of artificial neural network was applied to anticipate the results for the optimization of the work and output, which has also been a study of interest recently. In the current work, different blends of diesel with hydrogen, TGME as a fuel additive, and Al2O3 nanoparticles were utilized to check for the best performance and the least emissions. The best performance was seen with the inclusion of TGME in diesel along with hydrogen, while the use of nanoparticles increased CO formation. An improvement in the BTE was also found with the blends of TGME and nanoparticles in diesel along with hydrogen. The usage of TGME along with H2 performed the best in terms of BTE (15.8%) and while the least emission of NOx, HC, and CO was found with the combination of diesel and H2. The artificial neural network was applied afterwards to predict the results using the obtained data from the experimental results. It was found that the values of regression coefficients for BTE and ITE were close to 1 (0.99 for BTE and 0.98 for ITE). In the above cases, the value of the mean square error was also observed to be least. Furthermore, the results for the regression coefficient of emissions were close to 1 for NOx (0.94), HC (0.89), and CO (0.93) with minimum possible mean square errors in all the cases. The results showed that they were in line with the predicted data as well as the available literature for the anticipation of the obtained results.

Enhanced heat transfer rate on the flow of hybrid nanofluid through a rotating vertical cone: a statistical analysis

The recent study needs the optimal conditions for maximizing heat transfer rate with minimizing energy consumption. This is a basic objective of several industries in their production processes along with in improving the efficiency in electronic gadgets. Therefore, hybrid nanofluid plays an important role in enhancing heat transport phenomena. The current study investigates the improved heat transfer properties of a water-based hybrid nanofluid containing Al2O3 and Cu nanoparticles flowing through a rotating vertical cone embedded in a porous medium. The convective flow is enhanced by a magnetic field and thermal radiation, contributing to the complexity of the flow dynamics. However, the dimensional physical quantities are transformed to non-dimensional parameters by the implementation of suitable similarity rules. Furthermore, the transformed equations are numerically solved using a fourth-order Runge-Kutta shooting method. Henceforth, to get the optimal heat transfer rate, a robust statistical technique called response surface methodology (RSM) and for the validation a hypothetical test is organized by using analysis of variance. The parametric behavior is conducted via graphs and the physical description is presented briefly. Further, the major outcomes of the study are: both the particle concentrations attenuate the axial velocity whereas the fluid temperature enhances significantly. Increasing radiative heat augments the heat transport phenomena and the observation reveals that the case of hybrid nanofluids overrides the case of nanofluids.

Green Synthesis of Biochar@Al2O3 Nanocomposite from Waste Melia azedarach Fruit Biomass Pyrolysis: A Sustainable Solution for Photocatalytic Methylene Blue Dye Degradation

In this work, a green and sustainable approach used for synthesis of novel biochar@Al2O3 nanocomposite through pyrolysis of Melia azedarach (chinaberry) biomass coupled with Al2O3 nanoparticles from Phyllanthus emblica seed extract. The synthesized nanocomposite was analysed by UV-Vis spectroscope, FTIR, SEM, EDX and XRD were used to authenticate the distinct properties of the biochar@Al2O3 nanocomposite. These techniques are further used to examine the nanocomposite after photocatalytic degradation of methylene blue. Additionally, the scavenger impacts on dye degradation, stability and the potential reusability of the biochar@Al2O3 nanocomposite were examined in detail. The investigation evaluating the photocatalytic capability of biochar@Al2O3 nanocomposite for methylene blue degradation in wastewater revealed an impressive degradation efficiency of 97.36 %. Furthermore, after five cycles of reuse the nanocomposite retained a substantial degradation efficiency of 84.59 %. This research highlights the importance of presenting an efficient and eco-friendly method for water purification, emphasizing the role of biochar@Al2O3 nanocomposites in addressing environmental pollution through innovative nanomaterial applications. Significantly progresses was made in the development of sustainable materials for wastewater treatment, in particular the promising potential of the biochar@Al2O3 nanocomposite in methylene blue dye degradation.

Improving energy storage performance of PbZrO3-Al2O3 composite thin films by regulating distribution of Al2O3 nanoparticles

Improving energy storage performance of PbZrO3-Al2O3 composite thin films by regulating distribution of Al2O3 nanoparticles

Exploring the potential of anti-bacterial and conductive ZnO–Al2O3/SPES proton exchange membrane applied in MFC for sustainable energy generation and sugar beet industry effluent treatment

This research introduces a novel approach wherein a sulfonated polyethersulfone (SPES) membrane is modified using bio-synthesized ZnO–Al2O3 nanoparticles (ZANPs). This modified membrane serves as a proton exchange membrane (PEM) within a dual-chamber microbial fuel cell (MFC) for energy production and sugar beet industry effluent treatment. We fabricated ZANPs/SPES membranes through a phase inversion process, varying the ZANPs loadings from 0.5 to 4.0 wt%. The ZANPs underwent analysis using a range of methods, including FTIR, EDS, SEM, and XRD, and the PEMs were thoroughly studied through several analyses, such as FTIR, SEM, EDS, AFM, water contact angle, water uptake, zeta potential, oxygen permeability, ion exchange capacity, proton conductivity, COD removal, coulombic efficiency, and anti-bacterial efficiency. According to the findings, ZANPs exhibited significant benefits for modified PEMs, such as improved proton conductivity, ion exchange capacity, and anti-bacterial capability. The MFC utilizing PEM with 4.0 wt% of ZANPs (ZANPs4.0/SPES) demonstrated a peak power output of 142.75 mW/m2 and a maximum current of 413 mA/m2. The values observed were notably elevated compared to the MFC that used commercial Nafion 117. The ZANPs4.0/SPES also had a maximum ion exchange capacity of 2.75 meq/g and 3.91 mS/cm proton conductivity among the fabricated PEMs compared to Nafion117, which only had 1.07 mS/cm proton conductivity and ion exchange capacity of 0.89 meq/g. Modified membranes improved COD removal from sugar beet industry effluent by up to 98.22 % and had a higher coulombic efficiency of up to 39.26 %. The anti-bacterial efficiency of ZANPs4.0/SPES was over 97 % against two types of bacteria. As per the research findings, it is confirmed that the ZANPs/SPES membranes can function efficiently in dual-chamber MFCs.

Fabrication and characterization of Ti-12Mo/xAl2O3 bio-inert composite for dental prosthetic applications.

Introduction: Titanium (Ti)-molybdenum(Mo) composites reinforced with ceramic nanoparticles have recently significant interest among researchers as a new type of bio-inert material used for dental prosthetic applications due to its biocompatibility, outstanding physical, mechanical and corrosion properties. The current work investigates the impact of alumina (Al2O3) nanoparticles on the properties of the Ti-12Mo composite, including microstructure, density, hardness, wear resistance, and electrochemical behavior. Methods: Ti-12Mo/xAl2O3 nanocomposites reinforced with different Al2O3 nanoparticles content were prepared. The composition of each sample was adjusted through the mechanical milling of the elemental constituents of the sample for 24h under an argon atmosphere. The produced nanocomposite powders were then cold-pressed at 600 MPa and sintered at different temperatures (1,350°C, 1,450°C, and 1,500°C) for 90min. Based on density measurements using the Archimedes method, the most suitable sintering temperature was found to be 1,450°C. The morphology and chemical composition of the milled and sintered composites were analyzed using back-scattering scanning electron microscopy (SEM) and X-ray diffraction (XRD). Results and Discussion: The results showed that the addition of Mo increased the Ti density from 99.11% to 99.46%, while the incorporation of 15wt% Al2O3 in the Ti-12Mo composite decreased the density to 97.28%. Furthermore, the Vickers hardness and wear behavior of the Ti-Mo composite were enhanced with the addition of up to 5 wt% Al2O3. The sample contains 5 wt% Al2O3 exhibited a Vickers hardness of 593.4HV, compared to 320HV for pure Ti, and demonstrated the lowest wear rate of 0.0367mg/min, compared to 0.307mg/min for pure Ti. Electrochemical investigations revealed that the sintered Ti-12Mo/xAl2O3 nanocomposites displayed higher corrosion resistance against a simulated artificial saliva (AS) solution than pure Ti. The concentrations of Ti, Mo, and Al ions released from the Ti-12Mo/xAl2O3 nanocomposites in the AS solution were within the safe levels. It was found from this study that; the sample of the composition Ti-12Mo/5wt%Al2O3 exhibited appropriate mechanical properties, biocompatibility, corrosion resistance against the AS solution with acceptable ion concentration released in the biological fluids. Therefore, it can be considered as a new bio-inert material for potential applications in dental prosthetics.

Analysis of a CRDI diesel engine powered by ternary fuel blends (diesel, biodiesel, and pentanol) doped with alumina nano-additives

Environmental constraints associated with fossil fuels have driven researchers to find a novel, potential and environmentally benign alternative fuel. Biodiesel, vegetable oil, and alcohol have gained rapid momentum thanks to their renewable nature and comparable energy contents in recent years. Accordingly, a Ternary fuel blend is prepared comprising three fuels namely diesel, biodiesel, and pentanol. Waste cooking oil was identified as the source for biodiesel and Pentanol was chosen among various alcohol alternatives due to improved energy density, reduced toxicity. These are endorsed to the enhancement in surface area-volume ratio of nano additives which boosts the catalytic combustion activity and also causing lesser fuel to take part in combustion for maintaining a constant engine speed. The experimentation is done with ternaryfuel blends with varying pentanol and biodiesel concentrations of diesel, biodiesel and pentanol). Upon experimentation, it was observed that, ternary fuel blend ‘TF’ comprising 70% diesel, 20% biodiesel and 10% pentanol, yielded best performance and was used for doping of Alumina oxide (Al2O3) nano additives. The Al2O3 nanoparticles were doped with ternary blends at fractions of 10 ppm, 20 ppm, and 30 ppm. It was observed that 20 ppm Al2O3 nanoparticle blended TF blend improved BTE and lowered BSFC by about 12.01% and 22.57% respectively. The performance tremendously along with lowered the CO emission by 49.21%, HC emission by 18.91% and smoke opacity by 9.02%.

Thermal performance evaluation of the parabolic trough solar collector using nanofluids: A case study in the desert of Algeria

The use of Parabolic Trough Solar Collector (PTSC) is currently the best option for widespread application in industries operating at temperatures from 60 to 400 °C. Numerous studies have been conducted to enhance the thermal performance of the PTSC using synthetic oils as heat transfer fluids. In this study, the thermal performance of parabolic collectors was enhanced using Metallic Oxide Nanofluids (CuO, SiO2, Al2O3, TiO2) based on Therminol VP-1™ at 4 % volumetric concentration as heat-transmitting fluids. A thermal model was developed and validated through experimental and theoretical study, while the results showed good compatibility in the outlet temperature with an error rate of 0.184 % for experimental and 0.29 % for theoretical studies. Moreover, various theoretical models of the thermal properties of nanofluids were analyzed to determine the model that matches and simulates this study. The findings indicated that nanofluids enhanced the thermal efficiency of the PTSC system compared to pure Therminol VP-1™. Specifically, CuO/Therminol VP-1™ demonstrated the most significant improvement, increasing thermal efficiency by 1.03 %. Furthermore, the results also showed that the addition of CuO, TiO2, Al2O3, and SiO2 nanoparticles led to an increase in outlet temperature by 9.57 %, 6.04 %, 5.21 %, and 3.08 %, respectively.

Sustainable Al2O3 nanoparticles in catalytic pyrolysis: Unlocking high-yield bio-oil from Melia azedarach fruit biomass with comprehensive physicochemical analysis

The catalytic pyrolysis of Melia azedarach fruit biomass in the presence of aluminium oxide (Al2O3) nanoparticles was studied using a fixed bed reactor. Cost-effective and sustainable Al2O3 nanoparticles were employed as a catalyst in biomass pyrolysis and these nanoparticles were synthesized by using the extract of Phyllanthus emblica seeds as a reducing and capping agent. The confirmation of fabricated Al2O3 nanoparticles was analyzed by EDS, SEM and XRD characterization techniques. The potential effects of pyrolysis process parameters including catalyst dose, temperature and time were investigated. The optimized catalytic bio-oil was further characterized by FTIR spectroscopy. Moreover, physiochemical analyses were also performed to examine the bio-oil properties as fuel. This study demonstrates that catalytic bio-oil produced from Melia azedarach fruit biomass has the potential to be used as a substitute for fossil fuel for the generation of energy and industrial applications.

Eco-Friendly Synthesis of Al2O3 Nanoparticles: Comprehensive Characterization Properties, Mechanics, and Photocatalytic Dye Adsorption Study

Metal and metal oxide nanoparticles are gaining traction in inorganic catalysis and photocatalysis, driving the development of eco-friendly methods. This study introduces an eco-friendly and cost-effective approach for synthesizing Al2O3 nanoparticles (NPs) using extracts derived from the leaves of Calligonum comosum L. The primary objective of this investigation is to assess the photocatalytic efficacy of the synthesized catalyst in addressing organic pollutants. The Al2O3 NPs exhibit a spherical morphology with crystalline arrangements, as evidenced by an average crystallite size of 25.1 nm in the XRD analysis. The band gap energy of the Al2O3 NPs is determined to be 2.86 eV. In terms of mechanical properties, the Al2O3 NPs show significant potential in enhancing both flexural and compressive properties, thereby making them a viable choice for improving the mechanical performance of composites. Notably, the Young’s modulus of the hybrid composite (comprising plant material and Al2O3 NPs) exhibits a remarkable increase of 34.4% in flexion and 78.3% in compression compared to the plant material alone. The catalytic performance of the Al2O3 NPs is evaluated using methylene blue (MB) as a cationic dye and Rose Bengal (RB) as an anionic dye. Impressively, the Al2O3 NPs demonstrate degradation efficiencies of 98.2% for MB and 90.5% for RB. The degradation processes occur under solar light irradiation, with a contact time of 120 m, a maintained pH of 7, and a temperature of 25 °C. This study found that Al2O3 nanoparticles are a promising, cost-effective, and environmentally friendly option for water treatment.

A numerical simulation of heat transfer performance on MHD nanofluids in porous metal for enhancing CPU cooling efficiency

The main goal of this study is to enhance CPU cooling efficiency using nanofluids, and the novelty of the study lies in the investigation of heat transfer and convective flow of MHD nanofluid through porous metal structures and foam heat sink/source to improve CPU cooling efficiency. The governing equations for the flow model are solved using the BVP4C with MATLAB package through shooting techniques. The effects of various parameters on velocity, temperature fields, HT and drag force are discussed through graphical simulations. The results indicate that as the Reynolds and Darcy numbers rise, fluid flow velocity undergoes unique alterations. Higher Reynolds and Darcy numbers result in cooler temperatures, while higher heat generation lead to warmer temperatures.Boosting Prandtl number improves HT by 52% with Cu nanoparticles, whereas elevating heat generation values reduce HT by 6.43% more efficiently with Cu nanoparticles than Al2O3 nanoparticles. Raising the Hartmann number would boost drag force, but the Darcy number opposes it. An increase in Hartmann number leads to a decrease in HT by 30.16% for Al2O3-H2O nanofluids and 47.81% for Cu-H2O nanofluids. The findings contribute to the development of advanced computing devices, paving the way for more efficient and reliable electronic systems in various applications.

In Vitro Evaluation of DNA Damage Induction by Silver (Ag), Gold (Au), Silica (SiO2), and Aluminum Oxide (Al2O3) Nanoparticles in Human Peripheral Blood Mononuclear Cells.

Nanoparticles (NPs) are increasingly applied in a wide range of technological and medical applications. While their use offers numerous benefits, it also raises concerns regarding their safety. Therefore, understanding their cytotoxic effects and DNA-damaging properties is crucial for ensuring the safe application of NPs. In this study, DNA-damaging properties of PVP-coated silver, silica, aluminum oxide (13 nm and 50 nm), and gold (5 nm and 40 nm) NPs in human peripheral blood mononuclear cells (PBMCs) were investigated. NPs' internalization and induction of reactive oxygen species were evaluated using flow cytometry. Cytotoxic properties were determined using a dual acridine orange/ethidium bromide staining technique while DNA-damaging properties were assessed using an alkaline comet assay. We observed that Ag, SiO2, and both sizes of Al2O3 NPs were efficiently internalized by human PBMCs, but only PVP-AgNPs (at 10-30 µg/mL) and SiO2 NPs (at concentrations > 100 µg/mL) induced significant DNA damage after a 24 h exposure. In contrast, the uptake of both sizes of gold nanoparticles was limited, though they were able to cause significant DNA damage after a 3 h exposure. These findings highlight the different responses of human PBMCs to various NPs, emphasizing the importance of their size, composition, and internalization rates in nanotoxicology testing.

Characterization of Nanoparticles in Ethanolic Suspension Using Single Particle Inductively Coupled Plasma Mass Spectrometry: Application for Cementitious Systems.

Single particle inductively coupled plasma mass spectrometry (spICP-MS) is a well-established technique to characterize the size, particle number concentration (PNC), and elemental composition of engineered nanoparticles (NPs) and colloids in aqueous suspensions. However, a method capable of directly analyzing water-sensitive or highly reactive NPs in alcoholic suspension has not been reported yet. Here, we present a novel spICP-MS method for characterizing the main cement hydration product, i.e., calcium-silicate-hydrate (C-S-H) NPs, in ethanolic suspensions, responsible for cement strength. The method viability was tested on a wide range of NP compositions and sizes (i.e., from Au, SiO2, and Fe3O4 NP certified reference materials (CRMs) to synthetic C-S-H phases with known Ca/Si ratios and industrial cement hardening accelerators, X-Seed 100/500). Method validation includes comparisons to nanoparticle tracking analysis (NTA) and transmission/scanning electron microscopy (TEM/SEM). Results show that size distributions from spICP-MS were in good agreement with TEM and NTA for CRMs ≥ 51 nm and the synthetic C-S-H phases. The X-Seed samples showed significant differences in NP sizes depending on the elemental composition, i.e. CaO and SiO2 NPs were bigger than Al2O3 NPs. PNC via spICP-MS was successfully validated with an accuracy of 1 order of magnitude for CRMs and C-S-H phases. The spICP-MS Ca/Si ratios matched known ratios from synthetic C-S-H phases (0.6, 0.8, and 1.0). Overall, our method is applicable for the direct and element-specific quantification of fast nucleation and/or mineral formation processes characterizing NPs (ca. 50-1000 nm) in alcoholic suspensions.

Investigation on Mechanical Properties of Kevlar Fiber and Al2O3 – SiC used Nano-polymer Composite

Kevlar is a synthetic fiber that has become well-known all over the globe because of its many industrial uses. It functions well as a composite material and is mostly used in conjunction with other materials. This study discusses the fabrication of epoxy composites with different proportions of Al2O3 and SiC nanoparticles with Kevlar fiber. In this process, SiC, and Al2O3 nanoparticles were added to Kevlar fiber and fabricated the composite by a compressed moulding machine for shear, tensile and impact tests. From these test results, incorporating Al2O3 and SiC nanoparticles with Kevlar fiber under various compositions (1% to 4%) influences the composite mechanical behaviour such as strength. KBS 2 has the highest tensile strength of the four sample composites, measuring 5628 N/cm2, among the Kevlar fiber reinforced polymer composites containing epoxy resin. This is the highest value among the composite samples. Additionally, it is worth seeing that the shear strength of the Kevlar fiber-reinforced polymer composite featuring the KAS 2 value of 7735 N/cm2 has the highest value from the other composite including the KAS 1, KAS 3 and KAS 4. Moreover, the Kevlar fiber-reinforced polymer composite with KAS 2 (4.76 J) exhibits a larger impact strength than the composite with KAS 3 (3.42 J), KAS 1 (4.26 J, and KAS 4 (4.54 J). The findings indicate that Kevlar fiber reinforced with 3% Al2O3 and 2% SiC nanoparticles (KAS 2) exhibits superior strength and rigidity compared to the other nanoparticle combinations utilised in Kevlar fiber composites.

Advanced electrochemical synthesis and characterization of Al2O3 nanoparticles embedded in polyaniline matrix for optoelectronic applications

Nanocomposite materials, featuring conducting polymers and aluminum oxide nanoparticles (Al2O3-NPs), are revolutionizing various fields including biomedicine, optoelectronic devices, and dye adsorption. In this study, we report on the synthesis of Al2O3 nanoparticles embedded in a Polyaniline (PANI) matrix for the fabrication of Al2O3/PANI nanocomposite films. The electrodeposition method was employed to deposit these films onto ITO-glass substrates, with concentrations ranging from 5 % to 20 %. The optical properties of the nanocomposites were analyzed using UV–Vis spectroscopy, allowing the determination of the refractive index and absorption coefficients. In addition, the Scherrer equation was used to calculate the average crystallite size, providing insight into the microscopic, ordered regions within the material. With increasing nanoparticle concentration in PANI-Al2O3 nanocomposites, Tauc plots revealed an increase in energy band gaps from 3.70 eV to 3.85 eV. Additionally, optical bandgap energies increased in PANI- Al2O3 nanocomposites, while electrical conductivities decreased with higher Al2O3 NPs content. Incorporation of Al2O3 NPs reduced the degree of conjugated π-bonds in PANI and disrupted the ordered structure of polymer chains. Moreover, the SEM analysis confirmed that the nanocomposite films had a dense, fiber-like structure. Further analysis of FTIR and XRD data revealed interactions between Al2O3 nanoparticles and PANI chains. At lower concentrations, minimal interaction was observed, while higher concentrations resulted in enhanced molecular interactions, leading to improved chain stretching, molecular packing, and larger crystallite sizes. As a result of Al2O3 nanoparticle incorporation, the nanocomposites exhibited conductivity values ranging from 0.12 to 0.02 S cm−1. These engineered nanocomposite films, characterized by high crystallinity, varied electrical conductivities, and controlled band gaps, show promising potential as active components in next-generation optoelectronic devices.

Numerical and neural network approaches to heat transfer flow in MHD dissipative ternary fluid through Darcy-Forchheimer permeable channel

The study of heat transfer in fluid flows across permeable media is critical in many engineering applications, including energy systems, cooling technologies, and chemical processes. This study aims to explore the impact of joule heating and heat transfer flow of an MHD dissipative ternary fluid through a channel embedded in a Darcy-Forchheimer permeable medium. Additionally, the utilization of ternary hybrid nanofluids, composed of a base fluid and three nanoparticles Al2O3, MoS2, and Cu has emerged as a promising avenue for augmenting thermal conductivity and heat transfer rates. The governing equations are transformed into a set of coupled ordinary differential equations by employing similarity variables and simplified by bvp4c and artificial neural network (ANN) model approaches. Results reveal that significant enhancement in the velocity field at the lower channel wall and reductions at the upper wall, while fluid temperature decreases with increasing Prandtl number. Further, the heat transfer rate increases with an increase in the Prandtl number and magnetic field whereas the skin friction decays with an increase in the magnetic field. Meanwhile, the comparison was carried out for the temperature field by using bvp4c & ANN and the results are strongly correlated.

The Nanoparticle-induced Zener Pinning Effect on Strain-softening in a Cold-Worked Cu-Al2O3 Composite with 0.1 wt.% Al Content

The thermo-stability of microstructure during isothermal annealing at 900 °C and 1000 °C in a cold-worked Cu-Al2O3 composite with 0.1 wt.% Al content and its effect on resistance to softening were investigated in this paper. The results reveal that the microstructure following cold deformation consists of a Cu matrix with a refined grain size and high-density dislocations, accompanied by dispersed Al2O3 nanoparticles exhibiting an extremely low volume fraction. During isothermal annealing at 900 °C, the Al2O3 nanoparticles can strongly restrict the migration of the dislocations and suppress the recrystallization of the fine-grained Cu matrix by the Zener pinning effect. Furthermore, the presence of pinned dislocations facilitates the formation of sub-grain boundaries comprising high-density dislocations. Consequently, the Cu-Al2O3 composite with 0.1 wt.% Al content exhibits remarkable thermo-stability in its microstructure due to the incorporation of Al2O3 nanoparticles, resulting in a significantly elevated softening temperature of up to 1000 °C and thereby demonstrating excellent resistance against softening. However, the observed phenomenon of softening after isothermal annealing at 1000 °C for 5 hours can be attributed to extensive recrystallization growth that promotes twin boundary formation, primarily caused by the weakening Zener pinning effect resulting from Oswald ripening of Al2O3 and rod-like Al2O3 formation.

Tribological Properties of Nano-Scale Al2O3 Particles with Different Shapes as Lubricating Oil Additives

Enhancing lubrication across various tribological systems in the maritime industry is essential for improving safety, efficiency, and environmental sustainability. Al2O3 nanoparticles, employed as additives in lubricating oils, demonstrate favorable tribological properties including anti-wear and anti-friction characteristics. In this work, nano-scale γ-Al2O3 particles with different shapes, i.e., nanosheet, nanorod, nanosphere, and irregular-shaped nanoparticles, were prepared and calcinated forming the same crystalline phase with nanoscale size, which dispersed well in lubricating oil. The tribological properties of Al2O3 nanoparticles as lubricating oil additives were examined using block-on-ring wear tests, and the effects of the particle shape and particle concentration were investigated. The results indicated that the frictional properties are largely influenced by the particle shape and the concentration of the Al2O3 additives, with the optimal concentration being around 0.1 wt% for each shape. The lubricating oil with nanosheet additives presented the best tribological performance, followed by those with nanorod, nanosphere, and irregular-shaped Al2O3 nanoparticle additives. Al2O3 nanosheets as the lubricating oil additives reduced the stress effect on the friction surface because of their larger bearing area and are inter-particle-sheared during sliding due to the movement of friction pairs, which can further improve the tribological properties compared to other shapes.

Dielectric Characterization and Machine Learning-Based Predictions in Polymer Composites with Mixed Nanoparticles

Our research described in this manuscript investigated the dielectric properties and structural characteristics of Bisphenol-A epoxy resin composites infused with various concentrations (5 wt.%, 10 wt.%, and 15 wt.%) of hybrid nanofillers, namely alumina (Al2O3) and zinc oxide (ZnO). Ultrasonic dispersion was utilized to integrate the nanofillers into the resin matrix. Structural properties were assessed using X-ray diffraction (XRD), which confirmed the presence of the Al2O3 and ZnO nanoparticles within the epoxy matrix. Dielectric properties were measured over a frequency range of 104 Hz to 2 MHz. The results provide new insights into the polarization mechanisms and structural characteristics of these composites, highlighting their potential for enhanced dielectric performance in high-frequency applications. To further understand and predict these dielectric properties, the CatBoost and LightGBM regression models were employed to predict the dielectric constant (ε'), loss tangent (tan δ), and AC conductivity (σac) of these composites. The models demonstrated strong predictive accuracy, with performance metrics, including Mean Absolute Error (MAE), Root Mean Square Error (RMSE), and R-squared (R2), indicating the robustness and accuracy of the models in predicting the dielectric properties of the composites. The study’s findings underscore the significant potential of Bisphenol-A epoxy resin composites with hybrid nanofillers for high-frequency dielectric applications.

Investigation of combination of heat storage container and thermosyphon solar system in existence of nanomaterial

This research explores the combination of fins into thermosyphon solar collectors to enhance energy efficiency. The storage system includes a finned container filled with nanomaterial (a blend of Al2O3 nanoparticles and paraffin (RT30)), while the fluid circulating within the tube consists of a homogeneous mixture of copper nanoparticles and water. Unsteady laminar flow within a three-dimensional domain, incorporating gravitational forces, has been modeled. The numerical approach has undergone rigorous validation, demonstrating strong agreement with both experimental and numerical data. Effects of fin installation and nano-powder dispersion have been investigated across various scenarios. At t = 60 min, the liquid fraction (LF) is approximately 2.08 times higher in the system with fins compared to the simple case. LF progressively increases over time, reaching a value 3.1 times higher at t = 60 min compared to t = 30 min. The temperature of the nanofluid in the tank rises over time. Despite the enhanced nanofluid temperature in the tube due to fin presence, a decrease occurs within the domain due to accelerated melting rate in the container. Incorporation of nanoparticles into paraffin shows an improvement in LF by approximately 11.66 % in the presence of fins.