Potent antibacterial activity of MXene–functionalized graphene nanocomposites

Two dimensional (2D) nanomaterials display properties with significant biological utility (e.g., antimicrobial activity). In this study, MXene–functionalized graphene (FG) nanocomposites with Ti3C2Tx in varying ratios (FG : Ti3C2Tx, 25 : 75%, 50 : 50%, and 75 : 25%) were prepared and characterized via scanning electron microscopy, scanning electron microscopy-energy dispersive X-ray (SEM-EDX), high-resolution transmission electron microscopy (HRTEM), and zeta potential analysis. Their cytotoxicity was assessed using immortalized human keratinocytes (HaCaT) cells at three different timepoints, and antibacterial activity was assessed using Gram-positive Methicillin resistant Staphylococcus aureus, MRSA, and Gram-negative neuro-pathogenic Escherichia coli K1 (E. coli K1) in vitro. The nanomaterials and composites displayed potent antibacterial effects against both types of bacteria and low cytotoxicity against HaCaT cells at 200 μg mL−1, which is promising for their utilization for biomedical applications

Insight into the investigation of diamond nanoparticles suspended therminol 55 nanofluids on concentrated photovoltaic/thermal solar collector

Nanofluids are identified as advanced working fluids in the solar energy conversion field with superior heat transfer characteristics. This research work introduces carbon-based diamond nanomaterial and Therminol®55 oil-based nanofluids for implementation in a concentrated photovoltaic/thermal (CPV/T) solar collector. This study focuses on the experimental formulation, characterization of properties, and performance evaluation of the nanofluid-based CPV/T system. Thermo-physical (thermal conductivity, viscosity, and rheology), optical (UV-vis and FT-IR), and stability (Zeta potential) properties of the formulated nanofluids are characterized at 0.001–0.1 wt.% concentrations of dispersed particles using experimental assessment. The maximum photo-thermal energy conversion efficiency of the base fluid is improved by 120.80% at 0.1 wt.%. The thermal conductivity of pure oil is increased by adding the nanomaterial. The highest enhancement of 73.39% is observed for the TH-55/DP nanofluid. Furthermore, dynamic viscosity decreased dramatically across the temperature range studied (20–100 °C), and the nanofluid exhibited dominant Newtonian flow behavior, with viscosity remaining nearly constant up to a shear rate of 100 s−1. Numerical simulations of the nanofluid-operated CPV/T collector have disclosed substantial improvements. At a concentrated solar irradiance of 5000 W/m2 and an optimal flow rate of 3 L/min, the highest thermal and electrical energy conversion efficiency enhancements are found to be 11 and 1.8%, respectively

Improved thermophysical characteristics of a new class of ionic liquid + diethylene glycol/Al2O3 + CuO based ionanofluid as a coolant media for hybrid PV/T system

The purpose of this experimental research is to develop a new class of nanofluid as a replacement of conventional water based nanofluid for medium temperature range as PV/T coolant application. For the first time, hybridized Al2O3 + CuO nanoparticles were dispersed into the binary mixture of ionic liquid (IL) and diethylene glycol (DEG) without the addition of any stabilizing agents or surfactants. The formulated Ionanofluid posed excellent dispersion stability together with better thermal stability compared to water-based nanofluid, as evidenced from thermogravimetric analysis. The experimental thermal conductivity assessment showed a maximum of 41.8 % enhancement together with a 31 % penalty in pressure drop at 0.15 wt% concentration. A hybrid PVT system is constructed to numerically examine the effect of Ionanofluid as an active cooling medium under the COMSOL Multiphysics environment. Ionanofluids as coolants in a PVT panel showed a maximum of 69 % thermal efficiency at 0.15 wt% Al2O3 + CuO, higher than 63 % (0.10 wt% Al2O3 + CuO), 58 % (0.05 wt% Al2O3 + CuO), and 56 % (pure IL + DEG). The PV panel temperature was reduced from 65 to 40 °C when IL + DEG was replaced with 0.15 wt% Al2O3 + CuO. At the same concentrations, an electrical efficiency of nearly 12.7 % was observed, representing a 29.91 % improvement over IL + DEG at a flow rate of 4LPM. The formulated Ionanofluid performed thermally better than water but somewhat lower than water-based nanofluids like MWCNT/Water. Nevertheless, Ionanofluid's electrical efficiency was better than MWCNT/Water. Ionanofluid can be a viable alternative to water-based nanofluids for medium-temperature-based coolant applications. © 2022 Elsevier Lt

Review on thermal energy storage and eutectic nitrate salt melting point

In solar concentrates, thermal energy (TES) storage has a significant function (CSP). This article will discuss the forms of TES and TES content, focusing on the material for latent heat storage. Sensitive heat storage, latent heat storage and chemical reaction thermal storage classes can divide TES into three classes. Among the thermophysical properties for CSP is the latent heat storage content, which is used by more researchers. Dividing latent heat storage material into material for the organic, inorganic and eutetic phases change material (PCM). There are an advantage and downside to any form of storage material. Thermal stability at high temperature and low cost, however the specific heat capacity of the sensible heat storage material is very low compared to the latent heat storage materials.

Review of Ti3C2Tx MXene Nanofluids: Synthesis, Characterization, and Applications

MXene-based nanofluids are important because of their thermal and rheological properties, influencing scientific and industrial applications. MXenes, made of titanium carbides and nitrides, are investigated for nanofluid enhancement. This review covers MXene nanofluid creation, characterization, and application. To produce nanoscale MXene particles, two-dimensional materials are dissolved and dispersed in a base fluid. The stability and efficacy of MXene nanofluids depend on production methods, such as chemical exfoliation, electrochemical etching, and mechanical delamination. Improved heat transfer coefficients and thermal conductivity from MXene nanofluids help resolve heat transfer, energy efficiency, and thermal control problems. This extensive review also addresses long-term safety and the necessity for standardized characterization methodologies, helping researchers optimize MXene-based nanofluids in many technological fields

Experimental analysis on the performance, combustion/emission characteristics of a DI diesel engine using hydrogen in dual fuel mode

Among alternative fuels, hydrogen has significant promise as both a fuel and a carrier of energy. Hydrogen is projected to be a key alternative fuel in the near future to meet stringent pollution standards. Internal combustion (IC) engines, gas turbine, and aerospace industries use hydrogen as a fuel because it is non-toxic, odorless with high calorific value (CV), and combustible across a wide temperature range while also being a long-term renewable and less polluting energy source. The objective of this study is to investigate the impact of using different hydrogen rations on combustion behaver, engine performance, and emission characteristics in a dual fuel compressed ignition (CI) diesel engine. The tests were performed at speeds of 1500, 2000, and 2500 rpm at difference operating conditions. Hydrogen was introduced at flow rates of 21.4, 28.5, 36.2, 42.8, and 49.6 L per minute for each load. The findings reveal that hydrogen flow rate of 21.4 l/min and 42.8 l/min gives significant impact to engine coefficient of variation (COV) and the performance of the engine. In addition, the emissions level of CO, CO2 and smoke were improved at the same flow rate. Moreover, the break thermal efficiency (BTE) has shown significant improvement at 21.4 l/min of hydrogen flow rate due to the reduction in combustion length and the movement of the combustion phasing toward the ideal phase. The use of hydrogen as alternative energy has important role as a future green energy source

High Thermoelectric Performance of Multiwalled Carbon Nanotubes based Ionogels

Ionogels have emerged as promising thermoelectric materials with Seebeck coefficient 2–3 orders of magnitude higher than Seebeck coefficient of their inorganic counter parts. However, they suffer from the problem of low ionic conductivity, which can be improved with the addition of inorganic nanofillers to the ionogels. In the present work, thermoelectric performance of multiwall carbon nanotubes (MWCNTs) based ionogels (IGs) has been investigated. IGs were synthesized via in situ radical polymerization of polyethylene glycol 200 dimethacrylate (PEG200DMA) difunctional monomer in the presence of 1-butyl-3-methyl imidazolium tetrafluoroborate (an ionic liquid) and MWCNTs. Three composites namely MWCNTs-0.25, MWCNTs-0.5 and MWCNTs-1 were prepared having the concentration of MWCNTs by 0.25, 0.5 and 1 wt% respectively. A remarkable 75.3% enhancement in ionic conductivity was achieved for the MWCNTs-1 wt% ionogel compared to the base IG at 40 °C. This substantial improvement can be attributed to the "breathing polymer chain model," which describes the dissociation of ion aggregates due to the interaction between the ionic liquid and polymer chains. In terms of thermoelectric performance amongst the MWCNT ionogels, 0.25 wt% MWCNT-based ionogels was the optimized concentration with very high Seebeck coefficient of 1.70 mV/K and power factor of 4.1 µW/m. K along with excellent thermal stability up to 386 °C. These high-performing ionogels hold great promise for efficient utilization of low-grade thermal energy

Green Engineering with Nanofluids: Elevating Energy Efficiency and Sustainability

Colloidal suspensions of nanoparticles in a base fluid, known as nanofluids, have gained attention as a promising green technology with a lot of promise to address issues with sustainability and energy efficiency in a variety of industries. The main features and uses of nanofluids as a sustainable solution are summarized in this paper. Due to their high thermal conductivity and high surface area to volume ratio, nanoparticles give off exceptional thermal and heat transmission capabilities. They are a desirable option for boosting the effectiveness of heat exchange systems, such as refrigeration, air conditioning, and cooling in electronic equipment, due to their improved qualities. Higher heat transfer rates and lower energy consumption can be achieved by using nanofluids as coolants or heat transfer fluids, which lowers greenhouse gas emissions and energy expenditures. Nanofluids have also found use in the realm of renewable energy, where they can improve the performance of geothermal and solar thermal collectors. The capture and conversion of renewable energy sources can be greatly enhanced by using nanofluids as working fluids in these systems, helping to create a greener and more sustainable energy landscape. Additionally, environmental cleanup and pollution management could benefit from the use of nanofluids. They are appropriate for uses including wastewater treatment, oil spill cleanup, and air purification because of their special features that allow for effective heat transfer and pollutant absorption. Furthermore, nanofluids can significantly contribute to lowering the amount of water and energy used in industrial operations, thus advancing sustainability objectives. The numerous uses of nanofluids as a green technology are highlighted in this paper, with an emphasis on their potential to improve energy efficiency, lessen environmental impact, and contribute to a more sustainable future. As this area of study and development develops, nanofluids will be in a position to play a crucial part in resolving the urgent problems of our day

Enhancing stability and tribological applications using hybrid nanocellulose-copper (II) oxide (CNC-CuO) nanolubricant: An approach towards environmental sustainability

The primary aim of the present study is to assess the stability and efficacy of hybrid nanocellulose (CNC) and copper (II) oxide (CuO) nanoparticles when integrated into engine oil as a lubricant for piston ring-cylinder liner applications. The assessment of system stability was conducted by employing zeta potential measurements. Furthermore, the coefficient of friction and specific wear rate were determined by using hydrodynamic lubrication in circumstances characterised by high speed and low load, as well as boundary lubrication in situations characterised by low speed and high load. The trials used a specially constructed friction and wear testing device miming the contact geometry between piston rings and cylinder liners in an internal combustion engine. Alongside SAE 40 oil, several nanoparticle concentrations (0.1%, 0.3%, 0.5%, 0.7%, and 0.9% added to SAE 40) were examined. The stability of the nanolubricant increased from 0.1% to 0.5% concentration and then declined at 0.9% concentration, according to the zeta potential data. The graph showed that the 0.5% concentration of the nanolubricant had the highest mean zeta potential, indicating exceptional stability. The CNC-CuO nanolubricants showed notable reductions in the friction coefficient regarding tribological performance. The friction coefficient reduced between 33% and 44% in mixed lubrication and 48% and 50% in boundary lubrication. There was a 9–13% decrease in the friction coefficient when hydrodynamic lubrication was used. The CNC-CuO nanolubricant only showed light scuffing, while the SAE 40 sample showed severe exfoliation and scuffing. Wear rates had been enhanced by 33.5%. Overall, the 0.5% concentration of CNC-CuO nanoparticles improved the engine oil's thermophysical properties and performance

Enhancing Lubrication Efficiency and Wear Resistance in Mechanical Systems through the Application of Nanofluids: A Comprehensive Review

Due to its potential to increase lubrication effectiveness and reduce wear, nanofluids have drawn substantial interest in the field of mechanical systems. Colloidal suspensions of nanoparticles dispersed across a base fluid to create nanofluids. This comprehensive study's goal is to examine recent developments, scientific discoveries, and possible applications of nanofluids in tribology. The scientific and technical characteristics of materials which move in relation to one another are the subject of the academic topic of tribology. The aim of this review paper includes a thorough investigation of phenomena like lubrication mechanism, wear and friction. Because of their unique features at the nanoscale, nanoparticles offer a special opportunity to mitigate enduring problems in tribological systems. This review critically evaluates the process utilized to create nanofluids, examines their tribological properties, and considers how they affect the effectiveness of how mechanical systems function. The higher lubrication effectiveness and wear resistance are the main points of attention. This study also investigates several methods for characterizing nanofluids to examine their behavior. The assessment also emphasizes important elements that affect the effectiveness of nanofluids, including the composition, concentration, size, and choice of nanoparticles, in addition to the choice of the base fluid. This study examines many problems and probable future endeavors within the industry, encompassing inquiries pertaining to long-term durability, and scalability. The primary objective of this review paper is to conduct a comprehensive analysis of the current state of nanofluid research within the domain of tribology. The objective is to foster further progress and encourage the extensive adoption of nanofluids as an innovative lubricating technology